ES2357865T3 - PROCESS TO PRODUCE ISOCIANATES. - Google Patents

Abstract

Process for producing an isocyanate, which comprises reacting a carbamic acid ester and an aromatic hydroxy compound to obtain an aryl carbamate having a group derived from the aromatic hydroxy compound; and subjecting the aryl carbamate to a decomposition reaction, in which the aromatic hydroxy compound is an aromatic hydroxy compound that is represented by the following formula (1) and which has a substituent R 1, at least, in an ortho position of a hydroxyl group: in which ring A represents an aromatic hydrocarbon ring in the form of a single or multiple rings that can have a substituent and that have 6 to 20 carbon atoms; R 1 represents a different group of a hydrogen atom in the form of an aliphatic alkyl group having 1 to 20 carbon atoms, an aliphatic alkoxy group having 1 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, an aryloxy group having 6 to 20 carbon atoms, an aralkyl group having 7 to 20 carbon atoms or an aralkyloxy group having 7 to 20 carbon atoms, the group containing a selected atom between a carbon atom, an oxygen atom and a nitrogen atom; and R 1 can join A to form a ring structure.

Description

Technical sector

The present invention relates to a process for producing isocyanate. Technical background

Isocyanates are widely used as raw materials in the production of products such as polyurethane foam, paints and adhesives. The main process of industrial production of isocyanates involves reacting amines with phosgene (phosgene method), and almost all the amount of isocyanates produced worldwide are produced according to the phosgene method. However, the phosgene method presents numerous problems.

First, this method requires the use of a large amount of phosgene as a raw material. Phosgene is extremely toxic and requires special handling precautions to prevent the exposure of those who handle it, and also requires special devices to detoxify waste.

Secondly, since highly corrosive hydrogen chloride is produced in large quantities as a byproduct of the phosgene method, in addition to requiring a process to detoxify hydrogen chloride, in many cases the hydrolytic chlorine is contained in the isocyanates produced, which It can have a detrimental effect on the weather resistance and heat resistance of polyurethane products in the case of the use of isocyanates produced using the phosgene method.

Based on this background, a process has been sought to produce isocyanates that do not use phosgene. An example of a method for producing isocyanate compounds without using phosgene that has been proposed involves thermal decomposition of carbamic acid esters. It has long been known that isocyanates and hydroxy compounds are obtained by thermal decomposition of esters of carbamic acid (see, for example, Berichte der Deutschen Chemischen Gesellschaft [Reports of the German Chemical Society], Vol. 3, p. 653 , 1870). The basic reaction is illustrated by the following formula:

image 1

(where R represents an organic residue that has a valence of a, R ’represents a monovalent organic residue, and a represents an integer of 1 or more).

The thermal decomposition reaction represented by the aforementioned formula is reversible, and unlike the equilibrium thereof that is shifted to the carbamic acid ester on the left side at low temperatures, the isocyanate side and the hydroxy compound becomes predominantly at high temperatures. Therefore, it is necessary to carry out the thermal decomposition reaction of the carbamic acid ester at high temperatures. In addition, in the case of alkyl carbamates in particular, since the reaction rate is faster for the inverse thermal decomposition reaction, namely the reaction by which alkyl carbamate is formed from isocyanate and alcohol, the ester of carbamic acid ends up forming before the isocyanate and alcohol formed by thermal decomposition separate, thus frequently leading to an apparent difficulty in the progression of the thermal decomposition reaction.

On the other hand, the thermal decomposition of alkyl carbamates is susceptible to the simultaneous appearance of various irreversible side reactions, such as undesirable thermal denaturation reactions for alkyl carbamates or condensation of isocyanates formed by thermal decomposition. Examples of these side reactions include a reaction in which urea bonds are formed as represented by the following formula (2), a reaction in which carbodiimides are formed as represented by the following formula (3), and a reaction in which isocyanurates are formed as represented by the following formula (4) (see, Berichte der Deutschen Chemischen Gesellschaft [Reports of the German Chemical Society], Vol. 3, p. 653, 1870 and Journal of American Chemical Society [Journal of the American Chemical Society], Vol. 81, p. 2138, 1959):

image 1

In addition to these side reactions that lead to a reduction in the yield and selectivity of the target isocyanate, in the production of polyisocyanates in particular, these reactions can make long-term operation difficult as a result of, for example, causing precipitation of polymer solids. that clog the reaction vessel.

Various methods have been proposed to solve these problems. For example, a method has been proposed to produce polyisocyanate in which an alkyl polycarbamate, in which the ester groups are composed of alkoxy groups corresponding to a primary alcohol, is subjected to a transesterification reaction with a secondary alcohol to produce a alkyl polycarbamate in which the ester groups are composed of alkoxy groups corresponding to the secondary alcohol, followed by thermal decomposition of the alkyl polycarbamate (see, for example, International Publication No. WO 95/23484).

In this method it is described that the thermal decomposition temperature of the alkyl polycarbamate can be adjusted to a lower temperature by passing through an alkyl polycarbamate in which the ester groups are composed of alkoxy groups corresponding to the secondary alcohol, thus resulting in the effect of being able to inhibit the precipitation of the polymer solid. However, the reverse reaction rate between the polyisocyanate formed by the thermal decomposition reaction of the alkyl polycarbamate and the secondary alcohol remains rapid, thereby leaving the problem of inhibiting the formation of alkyl polycarbamate by the reverse reaction unresolved. .

An alternative method has been disclosed by which, in the production of aromatic isocyanates, for example, an aromatic alkyl polycarbamate and an aromatic hydroxy compound are subjected to a transesterification reaction to produce an aromatic aryl polycarbamate, followed by the thermal decomposition of aromatic aryl polycarbamate to produce an aromatic isocyanate (see, for example, US Patent No. 3,992,430). This method describes the effect of being able to adjust the temperature of thermal decomposition to a lower temperature by passing through an aromatic aryl polycarbamate. However, also in the case of this aromatic aryl polycarbamate, at temperatures such as those at which the transesterification reaction or thermal decomposition reaction is carried out, there are many cases in which secondary reactions such as those described above continue to occur, thus leaving the problem of improving isocyanate performance unresolved. Furthermore, it is known that thermal decomposition of N-substituted aromatic urethanes in the gas phase or liquid phase frequently results in the occurrence of various undesirable side reactions (see, for example, U.S. Patent No. 4,613,466 ).

EP1640357 discloses a process for producing hexamethylene diisocyanate comprising reacting 1,6-hexamethylenediamine with diphenyl carbonate to form the diphenyl ester intermediate of N, N'-hexanediylbis-carbamic acid followed by thermal decomposition of this intermediate to give hexamethylene diisocyanate.

Rudolf Leuckart "Über einige Synthesen mittelst Phenylcyanat" Journal fur Praktische Chemie ["About Synthesis by means of phenyl cyanate" Journal of Practical Chemistry], vol. 41, 1890, pages 301-329, discloses the thermal decomposition of orthotoluyl ester of phenylcarbamic acid to phenyl cyanate and ortho-cresol and the partial thermal decomposition of thymyl ester of phenylcarbamic acid in phenyl cyanol and thymol. Characteristics of the invention Problems to be solved by the invention

As described above, currently there are hardly any methods to produce industrial-scale polyisocyanates with favorable performance without using the extremely toxic phosgene.

An objective of the present invention is to disclose a process that allows isocyanates to be produced stably for a long period of time with high yield without

5 the appearance of the various problems found in the prior art when isocyanates are produced without using phosgens. Means to solve the problems

In view of the above, as a result of performing

In exhaustive studies on the problems mentioned above, the inventors of the present invention found that a production process in which a carbamic acid ester and a specific aromatic hydroxy compound undergo a transesterification reaction to produce an aryl carbamate, followed from

Subjecting the aryl carbamate to a thermal decomposition reaction to produce isocyanate allows solving the aforementioned problems, thereby leading to the completion of the present invention.

Specifically, the present invention discloses the following:

[1] a process for producing an isocyanate, comprising the

steps of: reacting a carbamic acid ester and an aromatic hydroxy compound to obtain an aryl carbamate having

A group derived from the aromatic hydroxy compound; and subjecting the aryl carbamate to a decomposition reaction, in which the aromatic hydroxy compound is an aromatic hydroxy compound that is represented by the following formula (5) and which has at least one R1 substituent in a

30 ortho position of a hydroxyl group:

image 1

(in which ring A represents an aromatic hydrocarbon ring in the form of a single or multiple rings that

they can have a substituent and they have 6 to 20 carbon atoms; R1 represents a different group of a hydrogen atom in the form of an aliphatic alkyl group having 1 to 20 atoms

5 carbon, an aliphatic alkoxy group having 1 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, an aryloxy group having 6 to 20 carbon atoms, an aralkyl group having 7 to 20 carbon atoms or an aralkyloxy group having 7 to 20 atoms of

10 carbon, the group containing an atom selected from a carbon atom, an oxygen atom and a nitrogen atom; and R1 can join A to form a ring structure),

[2] the process according to item [1], in which the hydroxy compound

Aromatic is a compound represented by the following formula (6):

image 1

(where ring A and R1 are the same as defined above, R2 represents a hydrogen atom or an aliphatic alkyl group

20 having 1 to 20 carbon atoms, an aliphatic alkoxy group having 1 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, an aryloxy group having 6 to 20 carbon atoms , an aralkyl group having 7 to 20 carbon atoms or aralkyloxy group having 7 to 20 atoms, containing

25 the aliphatic alkyl, aliphatic alkoxy, aryl, aryloxy, aralkyl and aralkyloxy groups an atom selected from a carbon atom, an oxygen atom and a nitrogen atom, and R2 can be attached to A to form a ring structure),

[3] the process according to item [2], in which in formula (6), a

The total number of carbon atoms constituting R1 and R2 is 2 to 20,

[4] the process according to any of items [1] to [3], wherein the A ring of the aromatic hydroxy compound comprises a structure containing at least one structure selected from the group consisting of a benzene ring, a naphthalene ring and an anthracene ring,

[5] the process according to item [4], wherein the aromatic hydroxy compound is a compound represented by the following formula (7):

image 1

(in which R1 and R2 are the same as defined above, and each of R3, R4 and R5 independently represents an atom of

10 hydrogen or an aliphatic alkyl group having 1 to 20 carbon atoms, an aliphatic alkoxy group having 1 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, an aryloxy group having 6 to 20 carbon atoms, an aralkyl group having 7 to 20 carbon atoms or a group

Aralkyloxy having 7 to 20 carbon atoms, containing the groups aliphatic alkyl, aliphatic alkoxy, aryl, aryloxy, aralkyl and aralkyloxy an atom selected from a carbon atom, an oxygen atom and a nitrogen atom),

[6] the process according to item [5], in which the hydroxy compound

Aromatic is such that in formula (7), each of R1 and R4 independently represents a group represented by the following formula (8), and R2, R3 and R5 represent a hydrogen atom:

image 1

25 (in which X represents a branched structure selected from the structures represented by the following formulas (9) and (10):

image 1

(where R6 represents a linear or branched alkyl group having 1 to 3 carbon atoms),

[7] the process according to item [5], wherein the aromatic hydroxy compound is such that in formula (3), R 1 represents a linear or branched alkyl group having 1 to 8 carbon atoms, and each of R2 and R4 independently represents a hydrogen atom or a linear or branched alkyl group having 1 to 8 carbon atoms,

[8] the process according to any of items [1] to [7], wherein the carbamic acid ester is an aliphatic carbamic acid ester, and a low boiling component formed with the aryl carbamate is a aliphatic alcohol,

[9] the process according to item [8], wherein the aliphatic carbamic acid ester is an aliphatic polycarbamic acid ester,

[10] the process according to item [8], which also includes the stages

of: continuously supplying the aliphatic carbamic acid ester and aromatic hydroxy compound to a reaction vessel to react to the aliphatic carbamic acid ester and aromatic hydroxy compound within the reaction vessel; recovering a low boiling component formed in the form of a gaseous component; and continuously withdrawing a reaction liquid containing aryl carbamate and the aromatic hydroxy compound from a lower part of the reaction vessel,

[11] the process according to any of items [1] to [10], in which the decomposition reaction is a thermal decomposition reaction, and is a reaction in which a corresponding isocyanate and an aromatic hydroxy compound are formed at from aryl carbamate,

[12] the process according to item [11] in which at least one isocyanate compound and aromatic hydroxy compound formed by the thermal decomposition reaction of aryl carbamate is recovered in the form of a gaseous component,

[13] the process according to item [8], wherein the aliphatic carbamic acid ester is a compound represented by the following formula (11):

image2

(in which R7 represents a group selected from the group consisting of an aliphatic group having 1 to 20 carbon atoms and an aromatic group having 6 to 20 carbon atoms, the group containing an atom selected from an atom of

15 carbon, an oxygen atom and a nitrogen atom, and having a valence of n, R8 represents an aliphatic group having 1 to 8 carbon atoms and containing an atom selected from a carbon atom, an oxygen atom and a nitrogen atom, and

20 n represents an integer from 1 to 10),

[14] the process according to item [13], wherein the aliphatic carbamic acid ester is such that R8 in the compound represented by the formula (11) is a group selected from the group consisting of an alkyl group having 1 to 20 atoms of

25 carbon and a cycloalkyl group having 5 to 20 carbon atoms,

[15] the process according to item [14], in which the aliphatic carbamic acid ester is at least one compound selected from the group consisting of compounds represented by the

30 following formulas (12), (13) and (14): (in which R8 is the same as defined above),

image 1

[16] an aryl polycarbamate represented by the following formula (15), (16) or (17):

image3

(in which a ring B represents a structure that can have

a substituent and containing at least one structure selected from the group consisting of a benzene ring, a naphthalene ring and an anthracene ring, R9 represents a different group of a hydrogen atom in form

5 of an aliphatic alkyl group having 1 to 20 carbon atoms, an aliphatic alkoxy group having 1 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, an aryloxy group having 6 at 20 carbon atoms, an aralkyl group having 7 to 20 carbon atoms or a group

10 aralkyloxy having 7 to 20 carbon atoms, the group containing an atom selected from a carbon atom, an oxygen atom and a nitrogen atom, and R10 represents an aliphatic alkyl group having 1 to 20 carbon atoms , an aliphatic alkoxy group having 1 to 20 atoms of

15 carbon, an aryl group having 6 to 20 carbon atoms, an aryloxy group having 6 to 20 carbon atoms, an aralkyl group having 7 to 20 carbon atoms or an aralkyloxy group having 7 to 20 carbon atoms, containing the groups aliphatic alkyl, aliphatic alkoxy, aryl, aryloxy,

20 aralkyl and aralkyloxy an atom selected from a carbon atom, an oxygen atom and a nitrogen atom),

[17] aryl polycarbamate according to item [16], which is represented by the following formula (18), (19) or (20): (in which R9 represents a different group of a hydrogen atom in the form of an aliphatic alkyl group having 1 to 20 carbon atoms, an aliphatic alkoxy group having 1 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, an aryloxy group having 6 to 20 carbon atoms, an aralkyl group having 7 to 20 carbon atoms or an aralkyloxy group having 7 to 20 carbon atoms, the group containing an atom selected from a carbon atom, an oxygen atom and an atom of nitrogen, and each of R10, R11, R12 and R13 independently represents a hydrogen atom or an aliphatic alkyl group having 1 to 20 carbon atoms, an aliphatic alkoxy group having 1 to 20 carbon atoms, a group aryl having 6 to 20 carbon atoms, an aryloxy group that has from 6 to 20 carbon atoms, an aralkyl group having 7 to 20 carbon atoms or an aralkyloxy group having 7 to 20 carbon atoms, containing the aliphatic alkyl, aliphatic alkoxy, aryl, aryloxy, aralkyl and aralkyloxy groups an atom selected from a carbon atom, an oxygen atom and a nitrogen atom). Advantageous effect of the invention

image 1

image 1

According to the present invention, an isocyanate can be efficiently produced without using phosgene. Brief description of the drawings

Figure 1 shows a conceptual drawing showing an apparatus

Continuous production to produce carbonic acid ester

according to an embodiment of the present invention;

Figure 2 shows a conceptual drawing showing an apparatus

transesterification reaction according to an embodiment of the

present invention;

Figure 3 shows a conceptual drawing showing an apparatus

of thermal decomposition reaction according to an embodiment of the present invention; Figure 4 shows a conceptual drawing showing a thermal decomposition reaction apparatus according to an embodiment of the present invention; Figure 5 shows a conceptual drawing showing an isocyanate production apparatus according to an embodiment of the present invention; Figure 6 shows the 1 H-NMR spectrum of the di (2,4-ditert-butylphenyl) ester of N, N'-hexanediyl bis-carbamic acid obtained in step (3-4) of Example 3 of the present invention ; and, Figure 7 shows the 13C-NMR spectrum of the N, N'-hexanediyl-bis-carbamic acid di (2,4-ditert-butylphenyl) ester obtained in step (3-4) of Example 3 of the present invention

Description of the reference numbers: (figure 1) -101-, -107-: distillation column, -102-: column type reaction vessel, -103-, -106-: thin film evaporator, -104- : autoclave, -105-: decarbonization tank, -111-, -112-, -117-: kettle, -121-, -123-, -126-, -127-: condenser, -1-, -9- : supply pipe, -2-, -4-, -5-, -6-, -7-, -8-, -10-, -11-, -12-, -13-, -14-: pipe transfer, -3-, -15-: recovery pipe, -16-: extraction pipe, -17-: feed pipe. (Figure 2) -201-: feed tank, -202-: thin film evaporator, -203-: distillation column, -204-: condenser, -21-, -22-, -23-, -24- , -25-, -26-, -27-, -28-, -29-: transfer pipe (figure 3) -301-: feed tank, -302-: thin film evaporator, -303-: column distillation, -304-: kettle, -305-: condenser, -31-, -32-, -33-, -34-, -35-, -36-, -37-, -38-, -39- , transfer pipe (figure 4) -401-: feed tank, -402-: thin film evaporator, -403-, -404-: distillation column, -405-, -407-, condenser, -406- , -408-: kettle, -41-, -42-, -43-, -44-,

-45-, -46-, -47-, -48-, -49-, -50-, -51-, -52-, -53-: pipe transfer (figure 5) -601-, -604-: agitation tank, -602-, -605-, -608-: tank,

5 -603-, -606-, -609-: thin film evaporator, -607-, -610-: distillation column, -611-, -613-: condenser, -612-: kettle, -61-, -62-, -63-, -64-, -65-, -66-, -67-, -68-, -69-, -70-, -71-, -72-, -73-, -74 -, -75-, -76-, -77-, -78-, -79-, -80-, -81-: transfer pipe

10 Best Mode for Carrying Out the Invention A detailed explanation of the best way to carry out the present invention (to be referred to as the present embodiment) is disclosed below. In addition, the present invention is not limited to the following present embodiment,

15 but can be modified in various ways within the scope of its essence. The isocyanate production process of the present embodiment is a process for producing isocyanates comprising the steps of: reacting a carbamic acid ester and a

Aromatic hydroxy compound to obtain an aryl carbamate having a group derived from the aromatic hydroxy compound; and subject the aryl carbamate to a decomposition reaction; wherein the aromatic hydroxy compound uses an aromatic compound that has a specific composition.

An example of the detailed reaction scheme of the present embodiment is indicated below. However, the isocyanate production process as claimed in the present invention is not limited to the following reaction scheme.

30 Table 1

image 1

To begin, an explanation of

those compounds used in the production process of isocyanate of the present embodiment. <Aromatic hydroxy compounds>

The aromatic hydroxy compounds used in the isocyanate production process of the present embodiment are aromatic hydroxy compounds that are represented by the following formula (5) and that have at least one substituent at an ortho site relative to a hydroxy group:

image 1

10 (in which ring A represents an aromatic hydrocarbon ring in the form of a single or multiple rings and having a substitute and having 6 to 20 carbon atoms;

R1 represents a different group of a hydrogen atom in the form of an aliphatic alkyl group having 1 to 15 carbon atoms, an aliphatic alkoxy group having 1 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, an aryloxy group having 6 to 20 carbon atoms, an aralkyl group having 7 to 20 carbon atoms or an aralkyloxy group having 7 to 20 carbon atoms, containing the

20 group an atom selected from a carbon atom, an oxygen atom and a nitrogen atom, and R1 can be attached to A to form a ring structure).

Examples of R1 in formula (1) above include aliphatic alkyl groups in which the number of carbon atoms that constitute the group is a number selected from integers from 1 to 20, such as a methyl group, an ethyl group , a propyl group (isomers), a butyl group (isomers), a pentyl group (isomers), a hexyl group (isomers), a heptyl group (isomers), an octyl group (isomers), a nonyl group (isomers), A decyl group (isomers), a dodecyl group (isomers), an octadecyl group (isomers) or the like; aliphatic alkoxy groups in which the number of carbon atoms constituting the group is a number selected from integers from 1 to 20, such as a

methoxy group, an ethoxy group, a propoxy group (isomers), a group

butyloxy

(isomers), a group pentyloxy (isomers), a group

hexyloxy

(isomers), a group heptyloxy (isomers), a group

octyloxy

(isomers), a group nonyloxy (isomers), a group

decyloxy (isomers), a dodecyloxy group (isomers), an octadecyloxy group (including isomers) or the like; aryl groups in which the number of carbon atoms constituting the group is from 6 to 20, such as a phenyl group, a methylphenyl group (isomers), an ethylphenyl group (isomers), a propylphenyl group (isomers), a group butylphenyl (isomers), a pentylphenyl group (isomers), a hexylphenyl group (isomers), a heptylphenyl group (isomers), an octylphenyl group (isomers), a nonylphenyl group (isomers), a decylphenyl group (isomers), a biphenyl group (isomers), a dimethylphenyl group (isomers), a diethylphenyl group (isomers), a dipropylphenyl group (isomers), a dibutylphenyl group (isomers), a dipentylphenyl group (isomers), a dihexylphenyl group (isomers), a diheptylphenyl group ( isomers), a terphenyl group (isomers), a trimethylphenyl group (isomers), a triethylphenyl group (isomers), a tripropylphenyl group (isomers), a tributhenyl phenyl group (isomers) or the like; aryloxy groups in which the number of carbon atoms constituting the group is from 6 to 20, such as a phenoxy group, a methylphenoxy group (isomers), an ethylphenoxy group (isomers), a propylphenoxy group (isomers), a group butylphenoxy (isomers), a penthenophenoxy group (isomers), a hexylphenoxy group (isomers), a heptylphenoxy group (isomers), an octylphenoxy group (isomers), a nonylphenoxy group (isomers), a decylphenoxy group (isomers), a phenylphenoxy group (isomers), a dimethylphenoxy group (isomers), a diethylphenoxy group (isomers), a dipropylphenoxy group (isomers), a dibutylphenoxy group (isomers), a dipenthenophenoxy group (isomers), a dihexylphenoxy group (isomers), a diheptylphenoxy group isomers), a diphenylphenoxy group (isomers), a trimethylphenoxy group (isomers), a triethylphenoxy group (isomers), a tripropylphenoxy group (isomers), a tributhephenoxy group (isomers) or the like; aralkyl groups in which the number of carbon atoms constituting the group is 7 to 20, such as a phenylmethyl group, a phenylethyl group (isomers), a phenylpropyl group (isomers), a phenylbutyl group (isomers), a group phenylpentyl (isomers), a phenylhexyl group (isomers), a phenylheptyl group (isomers), a phenyloctyl group (isomers), a phenylnonyl group (isomers) or the like; and aralkyloxy groups in which the number of carbon atoms that constitute the group is from 7 to 20, such as a phenylmethoxy group, a phenylethoxy group (isomers), a phenylpropyloxy group (isomers), a phenylbutyloxy group (isomers), a phenylpentyloxy group (isomers), a phenylhexyloxy group (isomers), a phenylheptyloxy group (isomers), a phenyloctyloxy group (isomers), a phenylnonyloxy group (isomers) or the like.

Examples of ring A in the formula (1) above include a benzene ring, a naphthalene ring, an anthracene ring, a phenanthrene ring, a naptacene ring, a chromene ring, a pyrene ring, a ring of triphenylene, a pentalene ring, a blue ring, a heptalene ring, an indacene ring, a biphenylene ring, an acenaphthylene ring, an aceantrylene ring, an acephenatrylene ring or the like, preferred examples include rings selected from the group consisting of a benzene ring, a naphthalene ring and an anthracene ring. In addition, these rings may have a substituent other than the R1 mentioned above, whose examples include aliphatic alkyl groups in which the number of carbon atoms constituting the group is a number selected from integers from 1 to 20, such as a methyl group , an ethyl group, a propyl group (isomers), a butyl group (isomers), a pentyl group (isomers), a hexyl group (isomers), a heptyl group (isomers), an octyl group (isomers), a nonyl group (isomers), a decyl group (isomers), a dodecyl group (isomers), an octadecyl group (isomers) or the like; aliphatic alkoxy groups in which the number of carbon atoms constituting the group is a number selected from integers from 1 to 20, such as a methoxy group, an ethoxy group, a propoxy group (isomers), a group

butyloxy

(isomers), a group pentyloxy (isomers), a group

hexyloxy

(isomers), a group heptyloxy (isomers), a group

octyloxy

(isomers), a group nonyloxy (isomers), a group

decyloxy (isomers), a dodecyloxy group (isomers), an octadecyloxy group (isomers) or the like; aryl groups in which the number of carbon atoms constituting the group is from 6 to 20, such as a phenyl group, a methylphenyl group (isomers), an ethylphenyl group (isomers), a propylphenyl group (isomers), a group butylphenyl (isomers), a pentylphenyl group (isomers), a hexylphenyl group (isomers), a heptylphenyl group (isomers), an octylphenyl group (isomers), a nonylphenyl group (isomers), a decylphenyl group (isomers), a biphenyl group (isomers), a dimethylphenyl group (isomers), a diethylphenyl group (isomers), a dipropylphenyl group (isomers), a dibutylphenyl group (isomers), a dipentylphenyl group (isomers), a dihexylphenyl group (isomers), a diheptylphenyl group ( isomers), a terphenyl group (isomers), a trimethylphenyl group (isomers), a triethylphenyl group (isomers), a tripropylphenyl group (isomers), a tributhenyl phenyl group (isomers) or the like; aryloxy groups in which the number of carbon atoms constituting the group is from 6 to 20, such as a phenoxy group, a methylphenoxy group (isomers), an ethylphenoxy group (isomers), a propylphenoxy group (isomers), a group butylphenoxy (isomers), a penthenophenoxy group (isomers), a hexylphenoxy group (isomers), a heptylphenoxy group (isomers), an octylphenoxy group (isomers), a nonylphenoxy group (isomers), a decylphenoxy group (isomers), a phenylphenoxy group (isomers), a dimethylphenoxy group (isomers), a diethylphenoxy group (isomers), a dipropylphenoxy group (isomers), a dibutylphenoxy group (isomers), a dipenthenophenoxy group (isomers), a dihexylphenoxy group (isomers), a diheptylphenoxy group isomers), a diphenylphenoxy group (isomers), a trimethylphenoxy group (isomers), a triethylphenoxy group (isomers), a tripropylphenoxy group (isomers), a tributhephenoxy group (isomers) or the like; aralkyl groups in which the number of carbon atoms constituting the group is 7 to 20, such as a phenylmethyl group, a phenylethyl group (isomers), a phenylpropyl group (isomers), a phenylbutyl group (isomers), a group phenylpentyl (isomers), a phenylhexyl group (isomers), a phenylheptyl group (isomers), a phenyloctyl group (isomers), a phenylnonyl group (isomers) or the like; and aralkyloxy groups in which the number of carbon atoms that constitute the group is from 7 to 20, such as a phenylmethoxy group, a phenylethoxy group (isomers), a phenylpropyloxy group (isomers), a phenylbutyloxy group (isomers), a phenylpentyloxy group (isomers), a phenylhexyloxy group (isomers), a phenylheptyloxy group (isomers), a phenyloctyloxy group (isomers) and a phenylnonyloxy group (isomers).

In addition, the aromatic hydroxy compounds may preferably be used either an aromatic hydroxy compound having a substituent in an ortho position relative to a hydroxyl group or an aromatic hydroxy compound having substituents in two ortho positions relative to a hydroxyl group, such as in the compounds represented by the following formula (6):

image 1

(in which ring A and R1 are the same as defined

10 above, R2 represents an aliphatic alkyl group having 1 to 20 carbon atoms, an aliphatic alkoxy group having 1 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, an aryloxy group that it has 6 to 20 carbon atoms, a

Aralkyl group having 7 to 20 carbon atoms or an aralkyloxy group having 7 to 20 atoms, containing the groups aliphatic alkyl, aliphatic alkoxy, aryl, aryloxy, aralkyl and aralkyloxy atoms selected from a carbon atom, an atom of oxygen and a nitrogen atom, and R2 can bind to A

20 to form a ring structure). Examples of R2 in the aforementioned formula (6) include a hydrogen atom; aliphatic alkyl groups in which the number of carbon atoms constituting the group is a number selected from integers from 1 to 20,

25 such as a methyl group, an ethyl group, a propyl group (isomers), a butyl group (isomers), a pentyl group (isomers), a hexyl group (isomers), a heptyl group (isomers), an octyl group ( isomers), a nonyl group (isomers), a decyl group (isomers), a dodecyl group (isomers), a group

Octadecyl (isomers) or the like; aliphatic alkoxy groups in which the number of carbon atoms constituting the group is a number selected from integers from 1 to 20, such as a methoxy group, an ethoxy group, a propoxy group (isomers), a butyloxy group (isomers ), a pentyloxy group (isomers), a hexyloxy group (isomers), a heptyloxy group (isomers), an octyloxy group (isomers), a nonyloxy group (isomers), a decyloxy group (isomers), a dodecyloxy group (isomers) , an octadecyloxy group (isomers) or the like; aryl groups in which the number of carbon atoms constituting the group is from 6 to 20, such as a phenyl group, a methylphenyl group (isomers), an ethylphenyl group (isomers), a propylphenyl group (isomers), a group butylphenyl (isomers), a pentylphenyl group (isomers), a hexylphenyl group (isomers), a heptylphenyl group (isomers), an octylphenyl group (isomers), a nonylphenyl group (isomers), a decylphenyl group (isomers), a biphenyl group (isomers), a dimethylphenyl group (isomers), a diethylphenyl group (isomers), a dipropylphenyl group (isomers), a dibutylphenyl group (isomers), a dipentylphenyl group (isomers), a dihexylphenyl group (isomers), a diheptylphenyl group ( isomers), a terphenyl group (isomers), a trimethylphenyl group (isomers), a triethylphenyl group (isomers), a tripropylphenyl group (isomers), a tributhenyl phenyl group (isomers) or the like; aryloxy groups in which the number of carbon atoms constituting the group is from 6 to 20, such as a phenoxy group, a methylphenoxy group (isomers), an ethylphenoxy group (isomers), a propylphenoxy group (isomers), a group butylphenoxy (isomers), a penthenophenoxy group (isomers), a hexylphenoxy group (isomers), a heptylphenoxy group (isomers), an octylphenoxy group (isomers), a nonylphenoxy group (isomers), a decylphenoxy group (isomers), a phenylphenoxy group (isomers), a dimethylphenoxy group (isomers), a diethylphenoxy group (isomers), a dipropylphenoxy group (isomers), a dibutylphenoxy group (isomers), a dipenthenophenoxy group (isomers), a dihexylphenoxy group (isomers), a diheptylphenoxy group isomers), a diphenylphenoxy group (isomers), a trimethylphenoxy group (isomers), a triethylphenoxy group (isomers), a tripropylphenoxy group (isomers), a tributhephenoxy group (isomers) or the like; aralkyl groups in which the number of carbon atoms constituting the group is 7 to 20, such as a phenylmethyl group, a phenylethyl group (isomers), a phenylpropyl group (isomers), a phenylbutyl group (isomers), a group phenylpentyl (isomers), a phenylhexyl group (isomers), a phenylheptyl group (isomers), a phenyloctyl group (isomers), a phenylnonyl group (isomers) or the like; and aralkyloxy groups in which the number of carbon atoms that constitute the group is from 7 to 20, such as a phenylmethoxy group, a phenylethoxy group (isomers), a phenylpropyloxy group (isomers), a phenylbutyloxy group (isomers), a phenylpentyloxy group (isomers), a

5 phenylhexyloxy group (isomers), a phenylheptyloxy group (isomers), a phenyloctyloxy group (isomers), a phenylnonyloxy group (isomers) or the like.

In the case where the aromatic hydroxy compounds used in the isocyanate production process of the present embodiment are aromatic hydroxy compounds having substituents in two ortho positions relative to a hydroxyl group, aromatic hydroxy compounds are preferably used in which the number Total carbon atoms constituting R1 and R2 are 2 to 20 among the compounds represented by the formula

15 mentioned above (6). There are no particular limitations to the combinations of R1 and R2 provided that the total number of carbon atoms constituting R1 and R2 is 2 to 20.

Examples of said aromatic hydroxy compounds include compounds represented by the following formula 20 (7):

image 1

(in which R1 and R2 are the same as defined above, and each of R3, R4 and R5 independently represents an atom of

Hydrogen or an aliphatic alkyl group having 1 to 20 carbon atoms, an aliphatic alkoxy group having 1 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, an aryloxy group having 6 to 20 carbon atoms, an aralkyl group having 7 to 20 carbon atoms or a group

Aralkyloxy having 7 to 20 carbon atoms, containing the groups aliphatic alkyl, aliphatic alkoxy, aryl, aryloxy, aralkyl and aralkyloxy an atom selected from a carbon atom, an oxygen atom and a nitrogen atom). In particular, compounds are preferably used

aromatic hydroxy in which each of R1 and R4 in the aforementioned formula (7) independently represents a group represented by the following formula (8) and R2, R3 and R5 represent hydrogen atoms, or aromatic hydroxy compounds in which R1 in the aforementioned formula (7) it is a linear or branched alkyl group having 1 to 8 carbon atoms and each of R2 and R4 independently represents a hydrogen atom or a linear or branched alkyl group having 1 to 8 carbon atoms:

image2

(in which X represents a branched structure selected from the structures represented by the following formulas (9) and (10):

image 1

15 (in which R6 represents a linear or branched alkyl group having 1 to 3 carbon atoms). Examples of such aromatic hydroxy compounds include 2-ethylphenol, 2-propylphenol (isomers), 2-butylphenol (isomers), 2-pentylphenol (isomers), 2-hexylphenol (isomers), 2

20 heptylphenol (isomers), 2,6-dimethylphenol, 2,4-diethylphenol, 2,6-diethylphenol, 2,4-dipropylphenol (isomers), 2,6-dipropylphenol (isomers), 2,4-dibutylphenol (isomers), 2 , 4-dipentylphenol (isomers), 2,4-dihexylphenol (isomers), 2,4-diheptylphenol (isomers), 2-methyl-6-ethylphenol, 2-methyl-6-propylphenol (isomers),

25 2-methyl-6-butylphenol (isomers), 2-methyl-6-pentylphenol (isomers), 2-ethyl-6-propylphenol (isomers), 2-ethyl-6-butylphenol (isomers), 2-ethyl-6-pentylphenol (isomers), 2-propyl-6-butylphenol (isomers), 2-ethyl-4-methylphenol (isomers), 2-ethyl-4-propylphenol (isomers), 2-ethyl-4-butylphenol (isomers), 2-ethyl-4- pentylphenol (isomers), 2-ethyl-4-hexylphenol (isomers), 2-ethyl-4-heptylphenol (isomers), 2-ethyl-4-octylphenol (isomers), 2-ethyl-4-phenylphenol (isomers), 2-ethyl-4-cumylphenol (isomers), 2-propyl-4-methylphenol (isomers), 2-propyl-4-ethylphenol (isomers), 2-propyl-4-butylphenol (isomers), 2-propyl-4-pentylphenol (isomers), 2-propyl-4- hexylphenol (isomers), 2-propyl-4-heptylphenol (isomers), 2-propyl-4-octylphenol (isomers), 2-propyl-4-phenylphenol (isomers), 2-propyl-4-cumylphenol (isomers), 2 -butyl-4-methylphenol (isomers), 2-butyl-4-ethylphenol (isomers), 2-butyl-4-propylphenol (isomers), 2-butyl-4-pentylphenol (isomers), 2-butyl-4-hexylphenol (isomers), 2-butyl-4-he ptilphenol (isomers), 2-butyl-4-octylphenol (isomers), 2-butyl-4-phenylphenol (isomers), 2-butyl-4-cumylphenol (isomers), 2-pentyl-4-methylphenol (isomers), 2 -pentyl-4-ethylphenol (isomers), 2-pentyl-4-propylphenol (isomers), 2-pentyl-4-butylphenol (isomers), 2-pentyl-4-hexylphenol (isomers), 2-pentyl-4-heptylphenol (isomers), 2-pentyl-4octylphenol (isomers), 2-pentyl-4-phenylphenol (isomers), 2-pentyl4-cumylphenol (isomers), 2-hexyl-4-methylphenol (isomers), 2-hexyl4-ethylphenol ( isomers), 2-hexyl-4-propylphenol (isomers), 2-hexyl4-butylphenol (isomers), 2-hexyl-4-pentylphenol (isomers), 2-hexyl4-heptylphenol (isomers), 2-hexyl-4-octylphenol (isomers), 2-hexyl4-phenylphenol (isomers), 2-hexyl-4-cumylphenol (isomers), 2-heptyl4-methylphenol (isomers), 2-heptyl-4-ethylphenol (isomers), 2-heptyl-4-propylphenol ( isomers), 2-heptyl-4-butylphenol (isomers), 2-heptyl-4-pentylphenol (isomers), 2-heptyl-4-hexylphenol (isomers), 2-heptyl-4-octylphenol (isomers), 2-heptyl-4 -fen ilphenol (isomers), 2-heptyl-4-cumylphenol (isomers), 2,4,6-trimethylphenol, 2,6-dimethyl4-ethylphenol, 2,6-dimethyl-4-propylphenol (isomers), 2,6-dimethyl -4butylphenol (isomers), 2,6-dimethyl-4-pentylphenol (isomers), 2,6

dimethyl-4-hexylphenol

(isomers), 2,6-dimethyl-4-phenylphenol

(isomers),

2,6-dimethyl-4-cumylphenol  (isomers), 2,4,6

triethylphenol,

2,6-diethyl-4-methylphenol, 2,6-diethyl-4-propylphenol

(isomers), 2,6-diethyl-4-butylphenol (isomers), 2,6-diethyl-4pentylphenol (isomers), 2,6-diethyl-4-hexylphenol (isomers), 2,6diethyl-4-phenylphenol (isomers ), 2,6-diethyl-4-cumylphenol (isomers), 2,4,6, -tripropylphenol (isomers), 2,6-dipropyl-4-ethylphenol (isomers), 2,6-dipropyl-4-methylphenol ( isomers), 2,6-dipropyl-4-butylphenol (isomers), 2,6-dipropyl-4-pentylphenol (isomers), 2,6-dipropyl-4-hexylphenol (isomers), 2,6-dipropyl-4-phenylphenol (isomers) , 2,6-Dipropyl-4-cumylphenol (isomers), 2,4-dimethyl-6-ethylphenol, 2-methyl-4,6-diethylphenol, 2-methyl-4-propyl-6-ethylphenol (isomers), 2-methyl -4-Butyl-6-ethylphenol (isomers), 2-methyl-4-pentyl-6-ethylphenol (isomers), 2-methyl-4-hexyl-6-ethylphenol (isomers), 2-methyl-4-phenyl-6- ethylphenol (isomers), 2-methyl-4cumyl-6-ethylphenol (isomers), 2,4-dimethyl-6-propylphenol (isomers), 2-methyl-4,6-dipropylphenol (isomers), 2-methyl-4- ethyl-6-propylphenol (isomers), 2-methyl-4-butyl-6-propylphenol (isomers), 2-methyl-4-pentyl-6-propylphenol (isomer s), 2-methyl-4-hexyl-6-propylphenol (isomers), 2-methyl-4-phenyl-6-propylphenol (isomers), 2-methyl-4cumyl-6-propylphenol (isomers), 2,4- dimethyl-6-butylphenol (isomers), 2-methyl-4,6-dibutylphenol (isomers), 2-methyl-4-propyl6-butylphenol (isomers), 2-methyl-4-ethyl-6-butylphenol (isomers), 2-methyl-4-pentyl-6-butylphenol (isomers), 2-methyl-4-hexyl-6-butylphenol (isomers), 2-methyl-4-phenyl-6-butylphenol (isomers), 2-methyl-4-cumyl-6-butylphenol (isomers), 2,4-dimethyl-6-pentylphenol, 2-methyl-4,6-dipentylphenol, 2-methyl-4-propyl-6-pentylphenol (isomers), 2-methyl-4-butyl-6-pentylphenol (isomers), 2-methyl-4-ethyl-6-pentylphenol (isomers), 2-methyl-4-hexyl-6-pentylphenol (isomers), 2-methyl-4-phenyl-6-pentylphenol (isomers), 2-methyl -4cumyl-6-pentylphenol (isomers), 2,4-dimethyl-6-hexylphenol, 2-methyl4,6-dihexylphenol, 2-methyl-4-propyl-6-hexylphenol (isomers), 2-methyl-4-butyl-6 -hexylphenol (isomers), 2-methyl-4-pentyl-6hexylphenol (isomers), 2-methyl-4-ethyl-6-hexylphenol (isomers), 2-methyl-4-phenyl- 6-hexylphenol (isomers), 2-methyl-4-cumyl-6-hexylphenol (isomers), 2-ethyl-4-methyl-6-propylphenol (isomers), 2,4-diethyl-6-propylphenol (isomers), 2- ethyl-4,6-dipropylphenol (isomers), 2-ethyl-4-butyl-6-propylphenol (isomers), 2-ethyl-4-pentyl-6-propylphenol (isomers), 2-ethyl-4-hexyl-6-propylphenol (isomers ), 2-ethyl-4-heptyl-6-propylphenol (isomers), 2-ethyl-4-octyl-6propylphenol (isomers), 2-ethyl-4-phenyl-6-propylphenol (isomers), 2-ethyl-4-cumyl-6 -propylphenol (isomers), 2-ethyl-4-methyl-6-butylphenol (isomers), 2,4-diethyl-6-butylphenol (isomers), 2-ethyl-4,6-dibutylphenol (isomers), 2-ethyl-4 -propyl-6-butylphenol (isomers), 2-ethyl-4-pentyl-6-butylphenol (isomers), 2-ethyl-4-hexyl-6-butylphenol (isomers), 2-ethyl-4-heptyl-6-butylphenol ( isomers), 2-ethyl-4-octyl-6-butylphenol (isomers), 2-ethyl-4-phenyl-6-butylphenol (isomers), 2-ethyl-4-cumyl-6-butylphenol (isomers), 2-ethyl- 4-methyl6-pentylphenol (isomers), 2,4-diethyl-6-pentylphenol (isomers), 2-ethyl-4,6-dipentylphenol (isomers), 2-ethyl -4-butyl-6-pentylphenol (isomers), 2-ethyl-4-propyl-6-pentylphenol (isomers), 2-ethyl-4hexyl-6-pentylphenol (isomers), 2-ethyl-4-heptyl-6- pentylphenol (isomers), 2-ethyl-4-octyl-6-pentylphenol (isomers), 2-ethyl-4phenyl-6-pentylphenol (isomers), 2-ethyl-4-cumyl-6-pentylphenol (isomers), 2- ethyl-4-methyl-6-hexylphenol (isomers), 2,4-diethyl-6-hexylphenol (isomers), 2-ethyl-4,6-dihexylphenol (isomers), 2-ethyl4-propyl-6-hexylphenol (isomers), 2-ethyl-4-pentyl-6-hexylphenol (isomers), 2-ethyl-4-butyl-6-hexylphenol (isomers), 2-ethyl-4-heptyl-6-hexylphenol (isomers), 2-ethyl-4-octyl -6-hexylphenol (isomers), 2-ethyl-4-phenyl-6-hexylphenol (isomers), 2-ethyl-4-cumyl6-hexylphenol (isomers), 2-propyl-4-methyl-6-butylphenol (isomers) , 2,4-dipropyl-6-butylphenol (isomers), 2-propyl-4,6-dibutylphenol (isomers), 2-propyl-4-ethyl-6-butylphenol (isomers), 2-propyl-4-pentyl-6- butylphenol (isomers), 2-propyl-4-hexyl-6-butylphenol (isomers), 2-propyl-4-heptyl-6-butylphenol (isomers), 2-propyl-4octyl-6- butylphenol (isomers), 2-propyl-4-phenyl-6-butylphenol (isomers) and 2-propyl-4-cumyl-6-butylphenol (isomers) or the like.

The inventors of the present invention surprisingly discovered that by using the specific aromatic hydroxy compounds as described above, esters of aromatic carbamic acid, which were conventionally considered to be unstable, are capable of inhibiting side reactions such as those described above in a reaction of transesterification and / or thermal decomposition reaction that will be described later. Although the mechanism by which the aromatic hydroxy compound inhibits side reactions is unclear, the inventors of the present invention assumed that in the case where, for example, R 'is a group derived from the aromatic hydroxy compound in the reaction by which forms a urea bond represented by the aforementioned formula (2), the substituent in the ortho position with respect to the hydroxyl group sterically protects the urethane bond, thereby impeding the reaction between a different carbamic acid ester and the urethane bond .

The aromatic hydroxy compounds are preferably aromatic hydroxy compounds having a standard boiling point higher than the standard boiling point of a hydroxy compound corresponding to an aliphatic alkoxy group, aryloxy group or aralkyloxy group which comprises the ester group of the carbamic acid ester Described below. The term "standard boiling point", as referred to herein

The invention indicates the boiling point at 1 atmosphere. <Carbamic acid esters>

There are no particular limitations with respect to the carbamic acid ester used in the isocyanate production process of the present embodiment, and preferably it is used

10 an aliphatic carbamic acid ester. Examples of aliphatic carbamic acid esters include compounds represented by the following formula (11):

image 1

(in which R7 represents a group selected from the group

15 composed of an aliphatic group having 1 to 20 carbon atoms and an aromatic group having 6 to 20 carbon atoms, the group containing an atom selected from a carbon atom and an oxygen atom, and having a number of atoms equal to an,

R8 represents an aliphatic group having 1 to 8 carbon atoms containing an atom selected from a carbon atom and an oxygen atom, and n represents an integer from 1 to 10). In the formula (11) above, n is preferably a

A number selected from whole numbers of 2 or more, and more preferably an aliphatic polycarbamic acid ester in which n is 2.

Examples of R7 in the formula (11) include linear hydrocarbon groups such as methylene, dimethylene, trimethylene, tetramethylene, pentamethylene, hexamethylene, octamethylene or the like; unsubstituted acyclic hydrocarbon groups such as cyclopentane, cyclohexane, cycloheptane, cyclooctane, bis (cyclohexyl) alkane or the like; alkyl substituted cyclohexanes such as methylcyclopentane, ethylcyclopentane, methylcyclohexane

(isomers), ethylcyclohexane (isomers), propylcyclohexane (isomers), butylcyclohexane (isomers), pentylcyclohexane (isomers), hexylcyclohexane (isomers) or the like; dialkyl substituted cyclohexanes such as dimethylcyclohexane (isomers), diethylcyclohexane (isomers), dibutylcyclohexane (isomers) or the like; Trialkyl-substituted cyclohexanes such as 1,5,5-trimethylcyclohexane, 1,5,5-triethylcyclohexane, 1,5,5-tripropylcyclohexane (isomers), 1,5,5-tributylcyclohexane (isomers) or the like; monoalkyl substituted benzenes such as toluene, ethylbenzene, propylbenzene or the like; dialkyl substituted benzenes such as xylene, diethylbenzene, dipropylbenzene or the like; and aromatic hydrocarbons such as diphenylalkane, benzene or the like. In particular, hexamethylene, phenylene, diphenylmethane, toluene, cyclohexane, xylene, methylcyclohexane, isophorone and dicyclohexylmethane are preferably used.

Examples of R8 include alkyl groups in which the number of carbon atoms constituting the group is selected from an integer from 1 to 8, such as a methyl group, an ethyl group, a propyl group (isomers), a group butyl (isomers), a pentyl group (isomers), a hexyl group (isomers), a heptyl group (isomers), an octyl group (isomers)

or similar; and cycloalkyl groups in which the number of carbon atoms constituting the group is selected from an integer from 5 to 14, such as a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, a dicyclopentyl group (isomers ), a dicyclohexyl group (isomers), a cyclohexylcyclopentyl group or the like.

Examples of alkyl polycarbamates represented by the aforementioned formula (11) include alkyl carbamates such as N, N'hexanediyl-bis-carbamic acid dimethyl ester, N, N'hexanediyl-bis-carbamic acid diethyl ester, ester N, N'hexanediyl-bis-carbamic acid dibutyl acid (isomers), N, N'-hexanediyl-bis-carbamic acid dipethyl ester (isomers), N, N'-hexanediyl-bis-carbamic acid dihexyl ester (isomers) ), N, N'-hexanediyl-bis-carbamic acid dioctyl ester (isomers), dimethyl-4,4'-methylene-dicyclohexyl carbamate, diethyl-4,4'methylene-dicyclohexyl carbamate, dipropyl-4 carbamate , 4'-Methylenedicyclohexyl (isomers), dibutyl-4,4'-methylene tricyclohexyl carbamate (isomers), dipentyl-4,4'-methylenedicyclohexyl carbamate (isomers), dihexyl-4,4'-methylene tricyclohexyl carbamate (isomers) , diheptyl-4,4'-methylenedicyclohexyl carbamate (isomers), carbamate of dioctyl-4,4'-methylenedicyclohexyl (isomers), methyl ester of 3 (methoxycarbonylamino-methyl) -3,5,5-trimethylcyclohexylcarbamic acid, ethyl ester of 3- (ethoxycarbonylamino-methyl) -3,5,5-trimethylcyclohexylcarbamic acid, 3 (propyloxycarbonylamino-methyl) -3,5,5-trimethylcyclohexylcarbamic acid (isomers), 3- (butyloxycarbonylaminomethyl) -3,5,5-trimethylcyclohexylcarbamic acid (isomers), pentyl ester of 3- ( Phenyloxycarbonylamino-methyl) -3,5,5-trimethylcyclohexylcarbamic acid (isomers), 3-hexyl ester of hexyl oxycarbonylamino-methyl) -3,5,5-trimethylcyclohexylcarbamic acid (isomers), 3- (heptyloxycarbonylaminomethyl) -3.5, heptyl ester 5-Trimethylcyclohexylcarbamic (isomers), 3- (octyloxycarbonylamino-methyl) octyl ester -3,5,5-trimethylcyclohexylcarbamic acid (isomers), toluene dicarbamic acid dimethyl ester (isomers), toluendicarbamic acid diethyl ester (isomer) meros), toluendicarbamic acid dipropyl ester (isomers), toluendicarbamic acid dibutyl ester (isomers), toluendicarbamic acid dipethyl ester (isomers), toluendicarbamic acid dihexyl ester (isomers), toluendicarbamic acid isomeric diheptyl ester (isomers) of toluendicarbamic acid (isomers), dimethyl ester of N, N '- (4,4'metanediyl-diphenyl) -biscarbamic acid, diethyl ester of N, N' (4,4'-methanediyl-diphenyl) -biscarbamic acid, ester N, N '- (4,4'-methanediyl diphenyl) -biscarbamic acid dipropyl, N, N' - (4,4'-methanediyl diphenyl) -biscarbamic acid dibutyl ester N, N '- (4,4'-methanediyl diphenyl) biscarbamic acid, N, N' - (4,4'-methanediyl diphenyl) biscarbamic acid dihexyl ester, N, N '- (4,4' diheptyl acid ester) -methanediyl diphenyl) -biscarbamic acid, dioctyl ester of N, N '- (4,4'methanediyl-dif enil) -biscarbamic or the like.

Among these, alkyl carbamates are preferably used in which R 7 in the formula (11) above is a group selected from the group consisting of an alkyl group having 1 to 20 carbon atoms and a cycloalkyl group having 5 to 20 carbon atoms, while alkyl carbamates represented by any of the following formulas (12) to (14) are used particularly preferably:

image3

(in which R8 is the same as defined above).

Examples of alkyl polycarbamates represented by the formula (12) include dimethyl ester of N, N'hexanediyl-bis-carbamic acid, diethyl ester of N, N 'acid

10 Hexanediyl bis-carbamic acid, N-hexanediyl bis-carbamic acid dibutyl ester (isomers), N-N-N-hexanodiyl bis-carbamic acid dipethyl ester (isomers), N, N 'dihexyl acid ester -hexanediyl bis-carbamic acid (isomers) and dioctyl ester of N, N'-hexanediyl bis-carbamic acid (including isomers).

In addition, examples of alkyl polycarbamates represented by formula (13) include dimethyl-4,4'methylene-dicyclohexyl carbamate, diethyl-4,4'-methylenedicyclohexyl carbamate, dipropyl-4,4'-methylene carbamate -dicyclohexyl (isomers), dibutyl-4,4'-methylene-dicyclohexyl carbamate

20 (isomers), dipentyl-4,4'-methylene-dicyclohexyl carbamate (isomers), dihexyl-4,4'-methylene-dicyclohexyl carbamate (isomers), diheptyl-4,4'-methylene-dicyclohexyl carbamate ( isomers) and dioctyl-4,4'-methylene-dicyclohexyl carbamate (isomers). In addition, examples of alkyl polycarbamates represented by the formula (14) include alkyl polycarbamates such as 3- (methoxycarbonylaminomethyl) -3,5,5-trimethylcyclohexylcarbamic acid methyl ester, 3- (ethoxycarbonylamino-methyl) ethyl ester -3,5,5-trimethylcyclohexylcarbamic,

5-Propyl ester of 3- (propyloxycarbonylamino-methyl) -3,5,5-trimethylcyclohexylcarbamic acid (isomers), butyl ester of 3 (butyloxycarbonylamino-methyl) -3,5,5-trimethylcyclohexylcarbamic acid (isomers), pentyl ester of 3- (pentyloxycarbonylaminomethyl) -3,5,5-trimethylcyclohexylcarbamic (isomers), hexyl ester

10 3- (hexyloxycarbonylamino-methyl) -3,5,5-trimethylcyclohexylcarbamic acid (isomers), 3- (heptyloxycarbonylamino-methyl) -3,5,5-trimethylcyclohexylcarbamic acid (isomers), 3- (octyl ester of 3- ( octyloxycarbonylaminomethyl) -3,5,5-trimethylcyclohexylcarbamic (isomers) or the like.

A known method can be used to produce carbamic acid esters. For example, carbamic esters can be produced by reacting amine compounds with carbon monoxide, oxygen and aliphatic alcohols or aromatic hydroxy compounds, or by reacting amine compounds with urea and

20 aliphatic alcohols or aromatic hydroxy compounds. In the present embodiment, carbamic acid esters are preferably produced by reacting carbonic acid esters and amine compounds.

An explanation of the production of alkyl carbamates by reacting dialkyl carbonates and amine compounds is given below.

The dialkyl carbonates represented by the following formula (21) can be used as dialkyl carbonates:

image4

(where R17 represents a linear or branched alkyl group having 1 to 8 carbon atoms).

Examples of R17 include alkyl groups in the form of aliphatic hydrocarbon groups in which the number of carbon atoms constituting the group is a number selected from an integer from 1 to 8, such as a methyl group, an ethyl group, a propyl group (isomers), a butyl group (isomers), a pentyl group (isomers), a hexyl group (isomers), a heptyl group (isomers), an octyl group (isomers) or the like. Examples of such dialkyl carbonates include dimethyl carbonate, diethyl carbonate, dipropyl carbonate (isomers), dibutyl carbonate (isomers), dipentyl carbonate (isomers), dihexyl carbonate (isomers), diheptyl carbonate (isomers ) and dioctyl carbonate (isomers). Among these, a dialkyl carbonate is particularly preferably used in the

10 that the number of carbon atoms that constitute the alkyl groups is a number selected from an integer from 4 to 6.

The amine compounds represented by the following formula (22) are preferably used as amine compounds:

image5

(in which R7 represents a group selected from the group consisting of an aliphatic group having 1 to 20 carbon atoms and an aromatic group having 6 to 20 carbon atoms, the group containing an atom selected from an atom of

20 carbon and an oxygen atom, and having a valence of n, and n represents an integer from 1 to 10). In the above formula (22), a polyamine compound is used in which n is preferably 1 to 3 and, more preferably, n is 2.

Examples of said polyamine compounds include aliphatic diamines such as hexamethylene diamine, 4,4'methylenebis (cyclohexylamine) (isomers), cyclohexanediamine (isomers), 3-aminomethyl-3,5,5-trimethylcyclohexylamine (isomers) or the like; and aromatic diamines such as phenylenediamine

30 (isomers), toluendiamine (isomers), 4,4'-methylenedianiline (isomers) or the like. Among these, aliphatic diamines such as hexamethylene diamine, 4,4'methylenebis (cyclohexylamine) (isomers), cyclohexanediamine (isomers), 3-aminomethyl-3,5,5-trimethylcyclohexylamine (isomers) are used or

35, while more preferably, 4,4'methylenebis (cyclohexylamine) and 3-aminomethyl-3,5,5 are used

32

trimethylcyclohexylamine.

The reaction conditions vary according to the compounds that react and, although dialkyl carbonate is preferably in excess based on the amino groups of the amine compound to accelerate the reaction rate and complete the reaction rapidly to a stoichiometric proportion of the dialkyl carbonate. with respect to amino groups of the amine compound in a range of 2 to 1000 times, the range preferably ranges between 2 and 100 times and more preferably between 2.5 and 30 times considering the reaction vessel. The reaction temperature is generally in the normal temperature range (20 ° C) to 300 ° C, and although higher temperatures are preferred to accelerate the reaction rate, since, conversely, undesirable reactions may occur at high temperatures, the temperature The reaction is preferably in the range of 50 to 150 ° C. A known cooling apparatus or heating apparatus may be installed in the reaction vessel to maintain a constant reaction temperature. In addition, although variable depending on the types of compounds used and the reaction temperature, the reaction pressure may be a reduced pressure, normal pressure.

or increased pressure, and the reaction is generally carried out at a pressure in the range between 20 and 1 x 106 Pa. There are no particular limitations regarding the reaction time (residence time in the case of a continuous method), and it is generally of 0.001 to 50 hours, preferably 0.01 to 10 hours and more preferably 0.1 to 5 hours. In addition, the reaction can also be completed by confirming that a desired amount of alkyl carbamate has been formed by, for example, liquid chromatography after sampling the reaction liquid. In the present embodiment, a catalyst may be used as necessary, and examples of catalysts that may be used include organic metal compounds and inorganic compounds of tin, lead, copper or titanium, and basic catalysts such as alkali metal alkylates or alkaline earth metals in the form of methylates, ethylates and butyrates (isomers) of lithium, sodium, potassium, calcium or barium. Although the use of a reaction solvent is not necessarily required in the present embodiment, a suitable inert solvent is preferably used as a reaction solvent in order to facilitate the reaction process, the examples of which include alkanes such as hexane (isomers), heptane (isomers), octane (isomers), nonane (isomers), decane (isomers) or the like; aromatic hydrocarbons and alkyl-substituted aromatic hydrocarbons such as benzene, toluene, xylene (isomers), ethylbenzene, diisopropylbenzene (isomers), dibutylbenzene (isomers), naphthalene or the like; aromatic compounds substituted by a halogen or a nitro group such as chlorobenzene, dichlorobenzene (isomers), bromobenzene, dibromobenzene (isomers), chloronaphthalene, bromonaphthalene, nitrobenzene, nitronaphthalene or the like; polycyclic hydrocarbon compounds such as diphenyl, substituted diphenyl, diphenylmethane, terphenyl, anthracene, dibenzyl toluene or the like; aliphatic hydrocarbons such as cyclohexane, cyclopentane, cyclooctane, ethylcyclohexane or the like; ketones such as methyl ethyl ketone, acetophenone or the like; esters such as dibutyl phthalate, dihexyl phthalate, dioctyl phthalate, benzylbutyl phthalate or the like; ethers and thioethers such as diphenyl ether, diphenyl sulfide or the like; and sulfoxides such as dimethylsulfoxide, diphenylsulfoxide or the like. These solvents can be used alone or two or more types can be used in the form of a mixture. In addition, dialkyl carbonate used in excess based on the amino groups of the amine compound is also preferably used as a solvent in the reaction.

A known tank reactor, column reactor or distillation column can be used as a reaction vessel, and although known materials can be used for the reaction vessel and the pipes provided, they have no detrimental effect on the starting substances or reagents, SUS304, SUS316 or SUS316L and the like can preferably be used, since they are economical. <Transesterification reaction>

In the isocyanate production process of the present embodiment, esters of carbamic acid and aromatic hydroxy compounds are first reacted to obtain aryl carbamates having a group derived from aromatic hydroxy compounds. This reaction involves an exchange between an aliphatic alkoxy group or aralkyloxy group that constitutes the ester group of the carbamic acid ester and an aryloxy group derived from the aromatic hydroxy compounds which results in the formation of the corresponding aryl carbamate and a hydroxy compound derived from the carbamic acid ester (and is referred to as a transesterification reaction in the present description).

Although variables according to the compounds that were reacted, the reaction conditions of this transesterification reaction are such that the aromatic hydroxy compound is used in the range of 2 to 1000 times the ester group of the carbamic acid ester when expressed as the proportion stoichiometric As a result of thorough studies, the inventors of the present invention surprisingly discovered that by using aromatic hydroxy compounds having a substituent at least in an ortho position with respect to the hydroxyl group in this transesterification reaction, as described above, the side reactions, as described above, attributable to the carbamic acid ester and / or product in the form of the aryl carbamate can be inhibited in the transesterification reaction. In the transesterification reaction, although the aromatic hydroxy compound is preferably used in excess based on the ester group of the carbamic acid ester to inhibit side reactions attributable to the carbamic acid ester and / or product in the form of the aryl carbamate, as well as to allowing the reaction to complete quickly, the aromatic hydroxy compound is preferably used in the range of 2 to 100 times and preferably in the range of 5 to 50 times considering the size of the reaction vessel. The reaction temperature is generally in the range of 100 to 300 ° C, and although higher temperatures are preferred to increase the reaction rate, since, conversely, there may be a greater susceptibility to the occurrence of secondary reactions at high temperatures, The reaction temperature is preferably in the range of 150 to 250 ° C. A known cooling apparatus or heating apparatus may be installed in the reaction vessel to maintain a constant reaction temperature. In addition, although variable depending on the types of compounds used and the reaction temperature, the reaction pressure may be reduced pressure, normal pressure or increased pressure, and the reaction is generally carried out at a pressure in the range of 20 to 1 x 106 Pa There are no particular limitations regarding the reaction time (residence time in the case of a continuous method) and it is generally from 0.001 to 100 hours, preferably from 0.01 to 50 hours and more preferably from 0.1 to 30 hours. In addition, the reaction can also be completed by confirming that a desired amount of aryl carbamate has been formed by, for example, liquid chromatography after sampling the reaction liquid. In the present embodiment, the catalyst is used from 0.01 to 30% by weight and preferably from 0.5 to 20% by weight based on the weight of the carbamic acid ester. For example, organic metal catalysts such as dibutyltin dilaurate, ferrous octoate or stannous octoate, or amines such as 1,4-diazabicyclo [2,2,2] octane, triethylenediamine or triethylamine are suitable for use, while catalysts of Organic metal such as dibutyltin dilaurate, ferrous octoate or stannous octoate are particularly preferred. These compounds can be used alone or two or more types can be used as a mixture. Although the use of a reaction solvent is not necessarily required in the present embodiment, a suitable inert solvent is preferably used as a reaction solvent in order to facilitate the reaction process, examples of which include alkanes such as hexane (isomers ), heptane (isomers), octane (isomers), nonane (isomers), decane (isomers) or the like; aromatic hydrocarbons and alkyl-substituted aromatic hydrocarbons such as benzene, toluene, xylene (isomers), ethylbenzene, diisopropylbenzene (isomers), dibutylbenzene (isomers), naphthalene or the like; aromatic compounds substituted by a halogen or a nitro group such as chlorobenzene, dichlorobenzene (isomers), bromobenzene, dibromobenzene (isomers), chloronaphthalene, bromonaphthalene, nitrobenzene, nitronaphthalene or the like; polycyclic hydrocarbon compounds such as diphenyl, substituted diphenyl, diphenylmethane, terphenyl, anthracene, dibenzyl toluene (isomers) or the like; aliphatic hydrocarbons such as cyclohexane, cyclopentane, cyclooctane, ethylcyclohexane or the like; ketones such as methyl ethyl ketone, acetophenone or the like; esters such as dibutyl phthalate, dihexyl phthalate, dioctyl phthalate, benzylbutyl phthalate or the like; ethers and thioethers such as diphenyl ether, diphenyl sulfide or the like; and sulfoxides such as dimethylsulfoxide, diphenylsulfoxide or the like; and silicone oil. These solvents can be used alone or two or more types can be used as a mixture.

As described above, although the transesterification reaction in the present embodiment involves the exchange between the aliphatic alkoxy group that constitutes the ester group of the carbamic acid ester and the aryloxy group derived from the aromatic hydroxy compound that results in the formation of corresponding aryl carbamates and alcohols, the transesterification reaction is an equilibrium reaction. Thus, to efficiently produce aryl carbamates by this transesterification reaction, it is preferred to remove the products from the reaction system. Since the compounds having the lowest standard boiling point in the reaction system are the alcohols formed by the transesterification reaction, the alcohols are preferably removed from the reaction system by a method such as distillation separation.

In addition, the transesterification reaction is preferably performed with a continuous method to allow the transesterification reaction to run efficiently. Specifically, a method is preferably used in which carbamic acid esters and aromatic hydroxy compounds are continuously supplied to the reaction vessel to carry out the transesterification reaction, the alcohols formed are removed from the reaction vessel in the form of the components. gaseous, and the reaction liquids containing the aryl carbamates formed and the aromatic hydroxy compounds are continuously removed from the bottom of the reaction vessel. In the case of performing the transesterification reaction according to this method, in addition to promoting the transesterification reaction, there is also the surprising effect of being able to improve the final yield of isocyanates by inhibiting side reactions as described above.

Although known materials can be used for the reaction vessel and the pipes used to carry out the transesterification reaction, provided they have no detrimental effect on the starting substances or reagents, SUS304, SUS316 or SUS316L and the like can preferably be used, since they are economical There are no particular limitations regarding the type of reaction vessel, and a known tank reactor or column reactor can be used. Preferably, a reaction vessel is used which is provided with pipes to extract a low boiling reaction mixture containing alcohol formed in the transesterification reaction of the reaction vessel in the form of the gaseous components, and to remove mixed liquids containing aryl carbamates and aromatic hydroxy compounds produced from the bottom of the reaction vessel in the form of a liquid. Various known methods are used for said reaction vessel, examples of which include types that use reaction vessels containing a stirring tank, a multi-stage stirring tank, a distillation column, a multi-stage distillation column, a multitubular reactor, a continuous multistage distillation column, a filled column, a thin film evaporator, a reactor provided with a support inside, a forced circulation reactor, a falling film evaporator, a falling drop evaporator , a drip flow reactor, a column of bubbles, and types that use combinations thereof. Methods using the thin film evaporator or column reactor are preferred from the viewpoint of effectively shifting the balance to the side of the products, while a structure having a large gas-liquid contact area is preferred to be capable of quickly transferring the alcohol formed to the gas phase.

The multi-stage distillation column refers to a distillation column that has multiple stages in which the number of theoretical distillation plates is 2 or more, and any multi-stage distillation column can be used as long as it allows continuous distillation . Any multi-stage distillation column may be used as a multi-stage distillation column, provided that it is ordinarily used as a multi-stage distillation column, examples of which include column types of dishes using a bubbling plate, a porous plate plate, a valve plate, a counter-current plate or the like, and types of filled column, filled with various types of fillers such as a Raschig ring, a Lessing ring, a polar piece ring, a Berl saddle, an Interlock saddle, a Dixon fill, a McMahon fill, Helipack, a Sulzer fill, Mellapak or the like. Any filled column may be used, provided that the column is filled with known filler materials as described above. In addition, a type of combination plate-fill column is also preferably used, which combines a part of plates with the filled part with the filling materials. The reaction vessel is preferably provided with a pipe for supplying a mixture containing the esters of carbamic acid and aromatic hydroxy compounds, a pipe for removing the components of the gas phase containing alcohols formed by the transesterification reaction, and a pipe for extracting mixed liquids containing the esters of carbamic acid and aromatic hydroxy compounds, and the pipe for removing the components of the gas phase containing the alcohols is preferably in a location that allows the components of the gas phase to be removed in the container of reaction, and the pipe for extracting the mixed liquids containing the aryl carbamates and the aromatic hydroxy compounds is particularly preferably located below it.

A pipe for supplying inert gas and / or liquid inert solvent from the bottom of the reaction vessel can be joined separately and, in the case where the mixed liquids containing the formed aryl carbamates and the aromatic hydroxy compounds contain esters of unreacted carbamic acid, a pipe can be attached to recirculate all or a part of the mixed liquids to the reaction vessel. See that, in the case of use of the inert solvent mentioned above, the inert solvent may be in the form of a gas and / or a liquid.

The gaseous components containing alcohols extracted from the reaction vessel can be purified using a known method, such as a distillation column, and the attached azeotropic and / or aromatic hydroxy compound and the like can be recycled. A device can be added to each pipe for

temper, cool or heat, considering the obstruction and Similar. <Aryl carbamates>

The aryl carbamates preferably produced by the transesterification reaction are aryl carbamates represented by any of the following formulas (15) to (17):

image 1

(in which ring B represents a structure that can have

A substituent and containing at least one structure selected from the group consisting of a benzene ring, a naphthalene ring and an anthracene ring, R9 represents a different group of a hydrogen atom in the form of an aliphatic alkyl group which has 1 to 20 atoms of

15 carbon, an aliphatic alkoxy group having 1 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, an aryloxy group having 6 to 20 carbon atoms, an aralkyl group having 7 at 20 carbon atoms or an aralkyloxy group having 7 to 20 carbon atoms, containing the

20 group an atom selected from a carbon atom, an oxygen atom and a nitrogen atom, and 40

R10 represents an aliphatic alkyl group having 1 to 20 carbon atoms, an aliphatic alkoxy group having 1 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, an aryloxy group having 6 at 20 carbon atoms, a group

5 aralkyl having 7 to 20 carbon atoms or an aralkyloxy group having 7 to 20 carbon atoms, the groups containing aliphatic alkyl, aliphatic alkoxy, aryl, aryloxy, aralkyl and aralkyloxy containing an atom selected from a carbon atom, an oxygen atom and a nitrogen atom).

Among these, the aryl carbamates most preferably produced are aryl carbamates represented by any of the following formulas (18) to (20):

image 1

(in which R9 represents a different group of an atom of

Hydrogen in the form of an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, an aryloxy group having 6 to 20 carbon atoms, an aralkyl group having 7 to 20 carbon atoms or an aralkyloxy group having 7 to 20 carbon atoms, the group containing an atom selected from a carbon atom, an oxygen atom and a nitrogen atom, and each of R10, R11, R12 and R13 independently represents a hydrogen atom or an aliphatic alkyl group having 1 to 20 carbon atoms, an aliphatic alkoxy group having 1 to 20 carbon atoms , an aryl group having 6 to 20 carbon atoms, an aryloxy group having 6 to 20 carbon atoms, an aralkyl group having 7 to 20 carbon atoms or an aralkyloxy group having 7 to 20 atoms carbon, containing the aliphatic alkyl groups, alkox and aliphatic, aryl, aryloxy, aralkyl and aralkyloxy an atom selected from a carbon atom, an oxygen atom and a nitrogen atom).

Examples of aryl polycarbamates represented by formula (18) include bis (2-ethylphenyl) N, N'-hexanediyl bis-carbamic acid, bis (2-propylphenyl) N, N'-hexanediyl- acid bis (2-propylphenyl) ester bis-carbamic (isomers), bis (2-butylphenyl) ester of N, N'-hexanediyl-bis-carbamic acid (isomers), bis (2-pentylphenyl) ester of N, N'-hexanediyl-bis-carbamic acid (isomers) , bis (2-hexylphenyl) ester of N, N'-hexanediylbis-carbamic acid (isomers), bis (2-octylphenyl) ester of N, N'-hexanediyl-bis-carbamic acid (isomers), bis (2-cumphenylphenyl) ester of N, N'-hexanediyl-bis-carbamic acid, bis (2,4-diethylphenyl) N, N'-hexanediyl-bis-carbamic acid ester, bis (2,4-dipropylphenyl) ester of N, N ' -hexanediyl biscarbamic acid (isomers), bis (2,4-dibutylphenyl) N, N'-hexanediyl bis-carbamic acid (isomers), bis (2,4-dipentylphenyl) ester of N, N'-hexanediyl-bis -carbamic ( isomers), bis (2,4-dihexylphenyl) ester of N, N'hexanediyl bis-carbamic acid (isomers), bis (2,4-dioctylphenyl) ester of N, N'-hexanediyl-bis-carbamic acid (isomers ), bis (2,4-dicumphenylphenyl) ester of N, N'-hexanediyl-bis-carbamic acid (isomers), bis (2,6-dimethylphenyl) ester of N, N'hexanediyl-bis-carbamic acid, bis (2) ester , 6-diethylphenyl) N, N'-hexanediyl bis-carbamic acid (isomers), bis (2,6-dipropylphenyl) ester of N, N'-hexanediyl bis-carbamic acid (isomers), bis (2,4) ester , 6-trimethylphenyl) of N, N'hexanediyl-bis-carbamic acid, bis (2,3,6-trimethylphenyl) ester of N, N'-hexanediyl-bis-carbamic acid, bis (2,4,6-triethylphenyl) ester of N, N'-hexanediyl bis-carbamic acid, and bis (2,4,6-tripropylphenyl) ester of N, N'-hexanediyl biscarbamic acid (isomers). Further, examples of alkyl polycarbamates represented by the formula (19) include bis (2-ethylphenyl) -4,4'-methylene-dicyclohexyl carbamate, bis (2-propylphenyl) -4,4'-methylene-dicyclohexyl carbamate ( isomers), bis (2-butylphenyl) -4,4'-methylene-dicyclohexyl carbamate (isomers), bis (2-pentylphenyl) -4,4'-methylene-dicyclohexyl carbamate (isomers), bis (2) carbamate -hexylphenyl) -4,4'-methylene-dicyclohexyl (isomers), bis (2-heptylphenyl) -4,4'-methylenedicyclohexyl carbamate (isomers), bis (2-octylphenyl) -4,4'methylene- carbamate dicyclohexyl (isomers), bis (2-cumylphenyl) 4,4'-methylene-dicyclohexyl carbamate (isomers), bis (2,4diethylphenyl) -4,4'-methylene-dicyclohexyl carbamate, bis (2,4-dipropylphenyl) carbamate ) -4,4'-methylene-dicyclohexyl (isomers), bis (2,4-dibutylphenyl) -4,4'-methylene-dicyclohexyl carbamate (isomers), bis (2,4-dipentylphenyl) -4, carbamate 4'-methylene-dicyclohexyl (isomers), bis (2,4-dihexylphenyl) carbamate - 4,4'-Methylenedicyclohexyl (isomers), bis (2,4-diheptylphenyl) -4,4'methylene-dicyclohexyl carbamate (isomers), bis (2,4-dioctylphenyl) -4,4'-methylene-dicyclohexyl carbamate ( isomers), bis (2,4-dicumylphenyl) -4,4'-methylene-dicyclohexyl carbamate, bis (2,6-dimethylphenyl) -4,4'-methylene-dicyclohexyl carbamate (isomers), bis ( 2,6-Diethylphenyl) -4,4'-methylene-dicyclohexyl (isomers), bis (2,6-dipropylphenyl) -4,4'-methylenedicyclohexyl carbamate (isomers), bis (2,4,6-) carbamate trimethylphenyl) 4,4'-methylene-dicyclohexyl (isomers), bis (2,4,6-triethylphenyl) -4,4'-methylene-dicyclohexyl carbamate (isomers) and bis (2,4,6-tripropylphenyl) carbamate - 4,4'-methylene-dicyclohexyl (isomers). In addition, examples of alkyl polycarbamates represented by formula (20) include 3- ((2-ethylphenoxy) carbonylamino-methyl) -3,5,5-trimethylcyclohexylcarbamic acid (2-ethylphenoxy) carbonate ester, (2-propylphenyl) ester of 3 - ((2-Butylphenoxy) carbonylamino-methyl) -3,5,5-trimethylcyclohexylcarbamic acid ((2-propylphenoxy) carbonylamino-methyl) -3,5,5-trimethylcyclohexylcarbamic (isomers), (2-butylphenoxy) carbonylamino-methyl) -3,5,5-trimethylcyclohexylcarbamic acid (isomers) ), 3 - ((2-penthenophenoxy) carbonylamino-methyl) -3,5,5-trimethylcyclohexylcarbamic acid (isomers), (2-hexylphenoxy) carbonylamino- (2-penthephenoxy) ester methyl) -3,5,5-trimethylcyclohexylcarbamic acid (isomers), 3- ((2-heptylphenoxy) carbonylamino-methyl) -3,5,5-trimethylcyclohexylcarbamic acid (isomers) ester, (2-octylphenyl) acid ester 3 - ((2-Octylphenoxy) carbonylamino-methyl) -3,5,5-trimethylcyclohexylcarbamic acid (isomers), 3 - ((2-cumyl) (2-cumyl) Phenoxy) carbonylamino-methyl) -3,5,5-trimethylcyclohexylcarbamic acid (isomers), 3- ((2,4-diethylphenoxy) carbonylamino-methyl acid) -3,5,5-trimethylcyclohexylcarbamic acid ester (2) , 3 - ((2,4-Dipropylphenoxy) carbonylamino-methyl) -3,5,5-trimethylcyclohexylcarbamic acid (isomers), 3- (2,4-dibutylphenoxy) ) Carbonylamino-methyl) -3,5,5-trimethylcyclohexylcarbamic acid (isomers), (2,4-dipentylphenoxy) carbonylaminomethyl) -3,5,5-trimethylcyclohexylcarbamic acid (isomers) ester (2) , 3 - ((2,4-Dihexylphenoxy) carbonylaminomethyl) -3,5,5-trimethylcyclohexylcarbamic acid (isomers), 3 ((2,4-diheptylphenoxy) carbonylaminomethyl) - 3,5,5-Trimethylcyclohexylcarbamic (isomers), (2,4-dioctylphenoxy) carbonylaminomethyl) -3,5,5-trimethylcyclohexylcarbamic acid (isomers), ester (2,4-dicyl-phenyl) Nyl) 3 - ((2,4-dicumylphenoxy) carbonylaminomethyl) -3,5,5-trimethylcyclohexylcarbamic acid, (2,6-dimethylphenoxy) carbonylaminomethyl) -3.5, 5 - Trimethylcyclohexylcarbamic acid, (2,6-diethylphenoxy) carbonylaminomethyl) -3,5,5-trimethylcyclohexylcarbamic acid ester (2,6-diethylphenoxy), 3 ((2,6-dipropylphenoxy) ) carbonylaminomethyl) -3,5,5-trimethylcyclohexylcarbamic acid (isomers), (2,4,6-trimethylphenoxy) carbonylaminomethyl) -3,5,5-trimethylcyclohexylcarbamic acid ester ((2,4,6-trimethylphenoxy) 2,4,6-triethylphenyl) 3- ((2,4,6-triethylphenoxy) carbonylamino acid

methyl) -3,5,5-trimethylcyclohexylcarbamic,

and ester (2,4,6

tripropylphenyl)

of the acid 3 - ((2,4,6

tripropylphenoxy) carbonylamino-methyl) -3,5,5

trimethylcyclohexylcarbamic (isomers).

The aryl carbamates produced in the transesterification reaction may undergo the subsequent thermal decomposition reaction while remaining a mixed liquid containing aryl carbamates and aromatic hydroxy compounds that are removed from the reactor, or the aryl carbamates may undergo the reaction. of thermal decomposition after purification of the mixed liquid. A known method can be used to purify the aryl carbamate from the reaction liquid, examples of which include the removal of the aromatic hydroxy compounds by distillation, solvent washing and purification of the aryl carbamates by crystallization.

Since the aryl carbamates of the present embodiment are esters of carbamic acid composed of aromatic hydroxy compounds and isocyanates, the thermal decomposition temperature is low as is generally known. In addition, the aryl carbamates of the present embodiment are, surprisingly, extremely resistant to the occurrence of side reactions (such as a reaction that results in the formation of a urea bond as described above) at high temperatures (such as 180oC) at which thermal decomposition is performed. Although the mechanism by which side reactions are inhibited is unclear, as described above, it is assumed that a substituent in the ortho position relative to the hydroxyl group sterically protects a urethane bond, thereby impeding the reaction between a different carbamic acid ester and urethane bond.

In addition, although the aromatic hydroxy compounds formed by the thermal decomposition reaction of the aryl carbamates of the present embodiment are aromatic hydroxy compounds having a substituent in the ortho position with respect to a hydroxyl group, since the reaction rate between Aromatic hydroxy compounds and isocyanates are surprisingly slow, specifically the reverse reaction rate in the thermal decomposition reaction is slow, when the thermal decomposition reaction is carried out in aryl carbamates, there is the advantage of being able to easily separate the aromatic hydroxy compounds and Isocyanates <Thermal decomposition reaction of aryl carbamates>

An explanation of the decomposition reaction of aryl carbamate of the present embodiment is given below.

The decomposition reaction of the present embodiment is a thermal decomposition reaction whereby isocyanates and corresponding aromatic hydroxy compounds are formed from aryl carbamates.

The reaction temperature is generally in the range of 100 to 300 ° C, and although a high temperature is preferred to increase the reaction rate, since secondary reactions, as described above, can be caused in reverse by carbamates of aryl and / or the reaction products in the form of isocyanates, the reaction temperature is preferably in the range of 150 to 250 ° C. A known cooling apparatus or heating apparatus may be installed in the reaction vessel to maintain a constant reaction temperature. In addition, although variable depending on the types of compounds used and the reaction temperature, the reaction pressure may be reduced pressure, normal pressure or increased pressure, and the reaction is usually carried out at a pressure in the range of 20 to 1 x 106 Pa There are no particular limitations regarding the reaction time (residence time in the case of a continuous method) and it is generally from 0.001 to 100 hours, preferably from 0.01 to 50 hours and more preferably from 0.1 to 30 hours. A catalyst can be used in the present embodiment, and the catalyst is used from 0.01 to 30% by weight and preferably from 0.5 to 20% by weight based on the weight of the aryl carbamates. For example, organic metal catalysts such as dibutyltin dilaurate, ferrous octoate, stannous octoate or the like, or amines such as 1,4-diazabicyclo [2,2,2] octane, triethylenediamine, triethylamine or the like are suitable for use as catalysts while that organic metal catalysts such as dibutyltin dilaurate, ferrous octoate, stannous octoate or the like are particularly preferred. These compounds can be used alone or two or more types can be used as a mixture. In the case of use of the catalysts in the transesterification reaction mentioned above, the catalysts contained in the mixed liquid after the transesterification reaction can be used as a catalyst in the thermal decomposition reaction or catalysts can be added again to the aryl carbamates when the thermal decomposition reaction is performed. Although the use of a reaction solvent is not necessarily required in the present embodiment, a suitable inert solvent can be used as a reaction solvent in order to facilitate the reaction process, examples of which include alkanes such as hexane (isomers), heptane (isomers), octane (isomers), nonane (isomers), decane (isomers) or the like; aromatic hydrocarbons and alkyl-substituted aromatic hydrocarbons such as benzene, toluene, xylene (isomers), ethylbenzene, diisopropylbenzene (isomers), dibutylbenzene (isomers), naphthalene or the like; aromatic compounds substituted by a halogen or a nitro group such as chlorobenzene, dichlorobenzene (isomers), bromobenzene, dibromobenzene (isomers), chloronaphthalene, bromonaphthalene, nitrobenzene, nitronaphthalene or the like; polycyclic hydrocarbon compounds such as diphenyl, substituted diphenyl, diphenylmethane, terphenyl, anthracene, dibenzyl toluene (isomers) or the like; aliphatic hydrocarbons such as cyclohexane, cyclopentane, cyclooctane, ethylcyclohexane or the like; ketones such as methyl ethyl ketone, acetophenone or the like; esters such as dibutyl phthalate, dihexyl phthalate, dioctyl phthalate, benzylbutyl phthalate or the like; ethers and thioethers such as diphenyl ether, diphenyl sulfide or the like; and sulfoxides such as dimethylsulfoxide, diphenylsulfoxide or the like; and, silicone oil. These solvents can be used alone or two

or more types can be used as a mixture.

As described above, although the thermal decomposition reaction of the present embodiment is a reaction whereby the corresponding isocyanates and aromatic hydroxy compounds are formed from aryl carbamates, the thermal decomposition reaction is an equilibrium reaction. Thus, to efficiently obtain isocyanates in this thermal decomposition reaction, it is preferred to remove at least one of the products of this thermal decomposition reaction in the form of the isocyanates and the aromatic hydroxy compounds of the thermal decomposition reaction system in form of a gaseous component by a method such as distillation. If the isocyanates or aromatic hydroxy compounds are removed as the gaseous components, it can be determined arbitrarily according to the compounds used, and, for example, the respective standard boiling points of the isocyanates and the aromatic hydroxy compounds are compared, followed by removal of compounds that have the lowest standard boiling point in the form of gaseous components.

Aryl carbamates are also susceptible to the occurrence of side reactions as described above, in the case where they are kept at high temperature for a long period of time, although to a much lesser extent than esters of carbamic acid. In addition, the aforementioned side reactions can also be induced by the isocyanates formed by the thermal decomposition reaction. Thus, the time during which aryl carbamates and isocyanates are maintained at high temperature is preferably as short as possible, and the thermal decomposition reaction is preferably carried out by the continuous method. The continuous method refers to a method in which aryl carbamates are continuously supplied to a reaction vessel where they undergo a thermal decomposition reaction and, at a minimum, the isocyanates or aromatic hydroxy compounds formed are removed from the reaction vessel in the form of a gaseous component.

Although known materials may be used for the reaction vessel and the pipes used to carry out the thermal decomposition reaction, provided they have no detrimental effect on aryl carbamate or products in the form of aromatic hydroxy compounds and isocyanates, SUS304, SUS316 or SUS316L and the like can preferably be used since they are economical. There are no particular limitations regarding the type of reaction vessel, and a known tank reactor or column reactor can be used. Preferably a reaction vessel is used which is provided with pipes to extract a low boiling mixture containing at least the isocyanates or aromatic hydroxy compounds formed in the thermal decomposition reaction of the reaction vessel in the form of the components. gaseous, and to remove mixed liquids containing unreacted aryl carbamates and compounds not extracted in the form of gaseous components from the bottom of the reaction vessel. Various known methods are used for such reaction vessels, the examples of which include types that use reaction vessels containing a stirring tank, a multi-stage stirring tank, a distillation column, a multi-stage distillation column, a reactor multitubular, a continuous multi-stage distillation column, a filled column, a thin film evaporator, a reactor provided with a support inside, a forced circulation reactor, a falling film evaporator, a falling drop evaporator, a drip flow reactor or a bubbling column, and types that use combinations thereof. The methods using the thin film evaporator or the column reactor are preferred, from the point of view of rapidly removing low boiling components from the reaction system, while a structure having a large gas-liquid contact area It is preferred to quickly transfer the low boiling components formed to the gas phase.

The reaction vessel is preferably provided with a pipe for supplying aryl carbamates, a pipe for removing a gaseous component containing at least isocyanates or aromatic hydroxy compounds formed by the thermal decomposition reaction, and a pipe for removing A mixed liquid containing the non-removed compounds as a gaseous component and unreacted aryl carbamates, the pipe for removing the gaseous components containing at least the isocyanates or aromatic hydroxy compounds is preferably located in a location that allows the Gaseous components in the reaction vessel are removed, and the pipe for extracting the mixed liquids containing the non-removed compounds as gaseous components and the unreacted aryl carbamates is particularly preferably located beneath it.

In addition, a pipe for supplying inert gas and / or liquid inert solvent from the bottom of the reaction vessel can be joined separately, and a pipe can also be attached to recirculate all or a part of the mixed liquid containing aryl carbamates without react and the compounds not removed as gaseous components to the reaction vessel. Equipment for tempering, cooling or heating can be added to each pipe, considering the obstruction and the like. In addition, in the case of use of the inert solvent mentioned above, the inert solvent may be in the form of a gas and / or a liquid.

The isocyanate obtained by the production process mentioned above can preferably be used as raw material for the production of polyurethane foam, paints, adhesives and the like. Since this process allows isocyanates to be produced efficiently without using extremely toxic phosgene, the present invention is extremely industrially significant. EXAMPLES

Although a detailed explanation of the present invention is disclosed below based on examples thereof, the scope of the present invention is not limited by these examples. <Analytical methods> 1) NMR analysis

Device: JNM-A400 FT-NMR system, JEOL Ltd., Japan

(one)

 Preparation of 1 H and 13 C NMR analysis samples

Approximately 0.3 g of sample solution was weighed, followed by the addition of approximately 0.7 g of heavy chloroform (99.8%, Aldrich Corp., United States) and approximately 0.05 g of internal standard in the form of tetramethyltin (guaranteed reagent, Wako Pure Chemical Industries, Ltd., Japan) and mixed until uniform to obtain solutions used as NMR analysis samples.

(2)

 Quantitative analysis

Analyzes were performed for each standard and quantitative analyzes were performed on the sample analysis solutions based on the resulting calibration curve. 2) Liquid chromatography

Device: LC-10AT system, Shimadzu Corp., Japan

Column: Silica-60 column, Tosoh Corp., Japan, two columns connected in series

Development solvent: Mixed liquid of

hexane / tetrahydrofuran (80/20) (v / v) Solvent flow rate: 2 ml / minute Column temperature: 35oC Detector: R.I. (refractometer)

(one)

 Analysis samples by liquid chromatography

Approximately 0.1 g of sample was weighed, followed by the addition of approximately 1 g of tetrahydrofuran (dehydrated, Wako Pure Chemical Industries, Ltd .; Japan) and approximately 0.02 g of internal standard in the form of bisphenol A (guaranteed reagent , Wako Pure Chemical Industries, Ltd., Japan) and mixed until uniform to obtain solutions used as analysis samples by liquid chromatography.

(2)

 Quantitative analysis

Analyzes were performed for each standard and quantitative analyzes were performed on the sample analysis solutions based on the resulting calibration curve. 3) Gas chromatography

Device: GC-2010, Shimadzu Corp., Japan Column: DB-1 column, Agilent Technologies Corp., United States, length: 30 m, internal diameter: 0.250 mm, film thickness: 1.00 m

Column temperature: Maintained at 50oC for 5 minutes, followed by a speed increase of 10oC / minute at 200oC; maintained at 200oC for 5 minutes, followed by speed increase of 10oC / minute up to 300oC

  Detector: FID

(one)

 Analysis samples by gas chromatography

Approximately 0.05 g of sample was weighed, followed by the addition of approximately 1 g of acetone (dehydrated, Wako Pure Chemical Industries, Ltd., Japan) and approximately 0.02 g of internal standard in the form of toluene (dehydrated, Wako Pure Chemical Industries, Ltd., Japan) and mixed until uniform to obtain solutions used as gas chromatography analysis samples.

(2)

 Quantitative analysis

Analyzes were performed for each standard and quantitative analyzes were performed on the sample analysis solutions based on the resulting calibration curve. [Reference Example 1] Production of bis (3-methylbutyl) carbonate Stage (I-1): Production of dialkyltin catalyst

625 g (2.7 moles) of di-n-butyltin oxide (Sankyo Organic Chemicals Co., Ltd., Japan) and 2020 g (22.7 moles) of 3-methyl-1-butanol (Kuraray Co., Ltd., Japan) in a 5000 ml pear-shaped volumetric flask. The flask was connected to an evaporator (R-144, Shibata Co., Ltd., Japan) to which an oil bath was connected (OBH-24, Masuda Corp., Japan) equipped with a temperature regulator, a pump vacuum (G50A, Ulvac Inc., Japan) and a vacuum controller (VC-10S, Okano Seisakusho Co., Ltd., Japan). The outlet of the purge valve of this evaporator was connected to a pipe containing nitrogen gas flowing at a normal pressure. After closing the evaporator purge valve to reduce the pressure inside the system, the purge valve gradually opened to allow nitrogen to flow into the system and return to normal pressure. The oil bath temperature was adjusted to approximately 145 ° C, the flask was immersed in the oil bath and evaporator rotation began. After heating for approximately 40 minutes in the presence of nitrogen at atmospheric pressure leaving the evaporator purge valve open, the distillation of 3-methyl-1-butanol containing water began. After maintenance in this state for 7 hours, the purge valve was closed, the pressure inside the system was gradually reduced, and the excess of 3-methyl-1-butanol was distilled with the pressure inside the system from 74 to 35 kPa . When the fraction no longer appeared, the flask was removed from the oil bath. After allowing the flask to cool to approximately room temperature (25 ° C), the flask was removed from the oil bath, the purge valve was opened gradually and the pressure inside the system was returned to atmospheric pressure. 1173 g of reaction liquid were obtained in the flask. Based on the results of 119Sn-, 1H- and 13C-NMR analysis, it was confirmed that 1,1,3,3-tetra-n-butyl1,3-bis (3-methylbutyloxy) diestanoxane had been obtained at a yield 99% based on di-n-butyltin oxide. The same procedure was then repeated 12 times to obtain a total of 10335 g of 1,1,3,3-tetra-n-butyl-1,3-bis (3-methylbutyloxy) diestanoxane. Stage (I-2): Production of bis (3-methylbutyl) carbonate

Bis (3-methylbutyl) carbonate was produced in a continuous production apparatus as shown in Figure 1. 1,1,3,3-tetrabutyl-1,3-bis (3-methylbutyloxy) diestanoxane produced in the manner described above, it was supplied at a speed of 4388 g / h from a transfer pipe -4- into a column-type reaction vessel -102- filled with the Metal Gauze CY filler (Sulzer Chemtech Ltd., Switzerland) and that it had an internal diameter of 151 mm and an effective length of 5040 mm, and purified 3-methyl-1-butanol was supplied with a distillation column -101- at the speed of 14953 g / h from a transfer pipe -2- . The temperature of the liquid inside the reaction vessel -102- was controlled at 160 ° C by means of a heater and a kettle -112-, and the pressure was adjusted to approximately 120 kPa-G with a pressure control valve. The residence time in the reaction vessel was approximately 17 minutes. 3-Methyl-1-butanol containing water was pumped at the rate of 15037 g / h from the top of the reaction vessel via a transfer pipe -6-, and 3-methyl-1-butanol at the rate of 825 g / h through the supply pipe -1-, to the distillation column -101- filled with the Metal Gauze CY filler and provided with a kettle -111- and a condenser -121- to carry out purification by distillation. At the top of the distillation column -101-, a fraction containing a high concentration of water was condensed by the condenser -121- and recovered from a recovery pipe -3-. Purified 3-methyl-1-butanol was pumped into the column-type reaction vessel -102- by transfer pipe -2- located at the bottom of the distillation column -101-. An alkyl alkyl tin alkoxide catalyst composition containing di-n-butyl-bis (3-methylbutyloxy) tin and 1,1,3,3-tetra-n-butyl-1,3bis (3-methylbutyloxy) diestanoxane was obtained from the bottom of the column-type reaction vessel -102-, and was supplied to a thin film evaporator -103- (Kobelco Eco-Solutions Co., Ltd., Japan) by means of a transfer pipe -5-. The 3-methyl1-butanol was removed by distillation in the thin film evaporator -103- and returned to the column-type reaction vessel -102- by a condenser -123-, a transfer pipe -8- and the pipeline transfer -4-. The alkyl tin alkoxide catalyst composition was pumped from the bottom of the thin film evaporator -103- through a transfer pipe -7- and supplied to an autoclave -104- while adjusting the di-n-butyl flow rate. -bis (3-methylbutyloxy) tin and 1,1,3,3-tetra-n-butyl-1,3-bis (3-methylbutyloxy) diestanoxane at about 5130 g / h. Carbon dioxide was supplied to the autoclave via a transfer pipe -9- at the rate of 973 g / h, and the pressure inside the autoclave was maintained at 4 MPa-G. The temperature inside the autoclave was set at 120 ° C, the residence time was adjusted to approximately 4 hours, and a reaction was carried out between the carbon dioxide and the alkyl tin alkoxide catalyst composition to obtain a reaction liquid containing carbonate of bis (3-methylbutyl). This reaction liquid was transferred to a decarbonization tank -105 through a transfer pipe -10- and a control valve to remove residual carbon dioxide, and the carbon dioxide was recovered from a transfer pipe -11-. Subsequently, the reaction liquid was transferred to a thin film evaporator (Kobelco Eco-Solutions Co., Ltd., Japan) -106- adjusted to approximately 142oC and approximately 0.5 kPa via a transfer pipe -12- and supplied while adjusting the flow rate of 1,1,3,3-tetra-n-butyl-1,3-bis (3-methylbutyloxy) diestanoxane to approximately 4388 g / h to obtain a fraction containing bis (3- carbonate) methylbutyl). On the other hand, the evaporation residue was circulated to the column-type reaction vessel -102- through the transfer pipe -13- and the transfer pipe -4- while adjusting the flow rate of 1,1,3, 3-tetra-n-butyl-1,3-bis (3-methylbutyloxy) diestanoxane at about 4388 g / h. The fraction containing bis (3-methylbutyl) carbonate was supplied to a distillation column -107- filled with the Metal Gauze CY filler and equipped with a kettle -117- and a condenser -127- by a condenser -126-y a transfer pipe -14-at the speed of 959 g / h followed by distillation purification to obtain 99% by weight of bis (3-methylbutyl) carbonate from a recovery pipe -16- at the speed of 944 g / h. When the alkyl tin alkoxide catalyst composition of a transfer pipe -13- was analyzed by 119Sn-, 1H- and 13C-NMR analysis, it was found to contain 1,1,3,3-tetra-n-butyl-1, 3-bis (3-methylbutyloxy) diestanoxane but did not contain di-n-butyl-bis (3-methylbutyloxy) tin. After performing the aforementioned continuous operation for approximately 240 hours, the alkyl tin alkoxide catalyst composition was extracted from an extraction pipe -16- at the rate of 18 g / h, while 1,1,3,3 -tetra-n-butyl-1,3-bis (3-methylbutyloxy) diestanoxane produced according to the above process was supplied from a feed pipe -17- at the rate of 18 g / h. [Reference example 2] Production of dibutyl carbonate Stage (II-1): Production of dialkyltin catalyst

692 g (2.78 mol) of di-n-butyl tin oxide and 2000 g (27 mol) of 1-butanol (Wako Pure Chemical Industries, Ltd., Japan) were placed in a 3000 ml pear-shaped volumetric flask. The flask containing the suspension-like white mixture was attached to an evaporator to which an oil bath equipped with a temperature regulator, a vacuum pump and a vacuum controller was connected. The outlet of the purge valve of this evaporator was connected to a pipe containing nitrogen gas flowing at normal pressure. After closing the evaporator purge valve to reduce the pressure inside the system, the purge valve gradually opened to allow nitrogen to flow into the system and return to normal pressure. The oil bath temperature was adjusted to approximately 126 ° C, the flask was immersed in the oil bath and evaporator rotation began. After rotation and heating for approximately 30 minutes under normal pressure leaving the evaporator purge valve open, the mixture boiled and the distillation of the low boiling component began. After maintaining it in this state for 8 hours, the purge valve was closed, the pressure inside the system was gradually reduced, and the low residual boiling component was removed by distillation with the pressure inside the system from 76 to 54 kPa. When the low boiling component no longer appeared, the flask was removed from the oil bath. The reaction liquid was in the form of a transparent liquid. The flask was subsequently removed from the oil bath, the purge valve was opened gradually and the pressure inside the system was returned to normal pressure. 952 g of reaction liquid were obtained in the flask. Based on the results of the 119Sn-, 1H- and 13C-NMR analyzes, a product was obtained in the form of 1,1,3,3-tetra-n-butyl-1,3-di (n-butyloxy) diestanoxane a 99% yield based on di-n-butyltin oxide. The same procedure was then repeated 12 times to obtain a total of 11480 g of 1,1,3,3-tetra-n-butyl-1,3-di (butyloxy) diestanoxane.

Stage (II-2): Dibutyl carbonate production

Carbonic acid ester was produced in a continuous production apparatus as shown in Figure 1. 1,1,3,3-tetra-n-butyl-1,3-di (n-butyloxy) diestanoxane produced in the product was supplied. step (II-1) at the speed of 4201 g / ha from the transfer pipe -4- into a column-type reaction vessel filled with the Mellapak 750Y filler (Sulzer Chemtech Ltd., Switzerland) and which had an internal diameter of 151 mm and an effective length of 5040 mm, and purified 1-butanol was supplied with the distillation column -101- to a column-type reaction vessel -102- at the speed of 24717 g / h from the feed pipe 2. The temperature of the liquid inside the reaction vessel was controlled at 160 ° C by means of a heater and a kettle -112-, and the pressure was adjusted to approximately 250 kPa-G with a pressure control valve. The residence time in the reaction vessel was approximately 10 minutes. 1-butanol containing water at the speed of 24715 g / h from the top of the reaction vessel was pumped through the transfer pipe -6-, and 1-butanol at the speed of 824 g / h through the feed pipe 1, to the distillation column -101- filled with the Metal Gauze CY filler (Sulzer Chemtech Ltd., Switzerland) and equipped with the kettle -111- and the condenser -121- to perform the distillation purification. At the top of the distillation column -101-, a fraction containing a high concentration of water was condensed by the condenser -121- and recovered from the transfer pipe -3-. Purified 1-butanol was pumped through the transfer pipe -2 located at the bottom of the distillation column -101-. An alkyl-alkoxide alkoxide catalyst composition containing di-n-butyltin di-n-butoxide and 1,1,3,3-tetra-n-butyl-1,3-di (n-butyloxy) diestanoxane was obtained from the bottom of the column-type reaction vessel -102-, and was supplied to the thin film evaporator -103- (Kobelco Eco-Solutions Co., Ltd., Japan) by means of a transfer pipe -5-. The 1-butanol was removed by distillation in the thin film evaporator -103- and returned to the column-type reaction vessel -102- through the condenser -123-, the transfer pipe -8- and the transfer pipe - 4-. The alkyl tin alkoxide catalyst composition was pumped from the bottom of the thin film evaporator -103 through the transfer pipe -7- and supplied to the autoclave -104- while adjusting the flow rate of the active components in the form of dibutoxide. dibutyltin and 1,1,3,3-tetra-n-butyl-1,3-di (n-butyloxy) diestanoxane at about 4812 g / h. Carbon dioxide was supplied to the autoclave via the feed line -9- at the rate of 973 g / h, and the pressure inside the autoclave was maintained at 4 MPa-G. The temperature inside the autoclave was set at 120 ° C, the residence time was adjusted to approximately 4 hours, and a reaction was carried out between the carbon dioxide and the alkyl tin alkoxide catalyst composition to obtain a reaction liquid containing carbonate of dibutyl This reaction liquid was transferred to the decarbonization tank -105- through the transfer line -10- and a control valve to remove residual carbon dioxide, and the carbon dioxide was recovered from the transfer line -11-. Subsequently, the reaction liquid was pumped to the thin film evaporator -106- (Kobelco Eco-Solutions Co., Ltd., Japan) adjusted to approximately 140oC and approximately 1.4 kPa via the transfer pipe -12- and supplied while adjusting the flow rate of 1,1,3,3-tetra-n-butyl-1,3-di (n-butyloxy) diestanoxane to approximately 4201 g / h to obtain a fraction containing dibutyl carbonate. On the other hand, the evaporation residue was circulated to the column-type reaction vessel -102- through the transfer pipe -13- and the transfer pipe -4- while adjusting the flow rate of 1,1,3,3 -tetra-n-butyl-1,3-di (n-butyloxy) diestanoxane at about 4201 g / h. The fraction containing dibutyl carbonate was supplied to the distillation column -107- filled with the Metal Gauze CY filler (Sulzer Chemtech Ltd., Switzerland) and equipped with the kettle -117- and the condenser -127- via the condenser - 126- and a transfer pipe -14- at the rate of 830 g / h, followed by purification by distillation to obtain 99% by weight of bis (3-methylbutyl) carbonate from the recovery pipe -16- at the speed of 814 g / h. When the alkyl tin alkoxide catalyst composition of the transfer pipe -13- was analyzed by 119Sn-, 1H- and 13C-NMR analysis, it was found to contain 1,1,3,3-tetra-n-butyl-1, 3-di (n-butyloxy) diestanoxane but did not contain di-n-butyltin di-n-butoxide. After performing the aforementioned continuous operation for approximately 600 hours, the alkyl tin alkoxide catalyst composition was extracted from the extraction line -16- at the rate of 16 g / h, while 1,1,3 was supplied, 3-tetra-n-butyl-1,3-di (n-butyloxy) diestanoxane produced in step (II-1) from the feed line -17- at the rate of 16 g / h. [Example 1] Stage (1-1): Production of di (3-methylbutyl) ester of N, N’-hexanediyl-bis-carbamic acid

1818 g (9.0 moles) of bis (3-methylbutyl) carbonate and 208.8 g (1.8 moles) of hexamethylenediamine (Aldrich Corp., United States) were placed in a 5-mouth four-volume volumetric flask. He placed a stirrer in the flask, and a Dimroth condenser and a three-way valve were attached to the flask. After replacing the interior of the system with nitrogen, the four-mouth flask was immersed in an oil bath (OBH-24, Masuda Corp., Japan) heated to 80 ° C followed by the addition of 3.5 g of sodium methoxide (solution in 28% methanol, Wako Pure Chemical Industries, Ltd., Japan) to start the reaction. Samples of the reaction liquid were properly collected and subjected to NMR analysis, and the reaction was interrupted at the point where hexamethylenediamine was no longer detected. As a result of the analysis of the resulting solution by liquid chromatography, it was found that the solution contained 29.9% by weight of di (3-methylbutyl) ester of N, N’-hexanediyl-bis-carbamic acid. Stage (1-2): Distillation of the low boiling component

The solution obtained in step (1-1) was placed in a 5 l volumetric flask equipped with a three-way valve, a condenser, a distillate manifold and a thermometer, and the inside of the flask was replaced by vacuum nitrogen . The flask was immersed in an oil bath heated to approximately 130 ° C. Distillation was performed while gradually reducing the pressure in the flask to a final pressure of 0.02 kPa. 1410 g of distillate were obtained. As a result of the analysis by gas chromatography, it was discovered that the distillate was a solution containing 78.3% by weight of bis (3-methylbutyl) carbonate and 21.4% by weight of isoamyl alcohol. In addition, as a result of the analysis of the resulting distillation residue in the flask by liquid chromatography, it was discovered that the distillation residue contained 98.0% by weight of di (3-methylbutyl) ester of N, N'-hexanediyl-bis acid -carbamic Step (1-3): Production of di (2,4-di-tert-amylphenyl) ester of N, N'-hexanediyl-bis-carbamic acid by transesterification

A transesterification reaction was performed in a reaction apparatus as shown in Figure 2.

111 g of dibutyltin dilaurate (chemical quality, Wako Pure Chemical Industries, Ltd., Japan) and 4119 g of 2,4-di-tert-amylphenol (Tokyo Chemical Industry Co., Ltd., Japan) were added to 618 g of the distillation residue obtained in step (1-2) and stirred to obtain a homogeneous solution which was then placed in a feed tank -201-. A thin film distillation apparatus -202- (Kobelco Eco-Solutions Co., Ltd., Japan) having a heat conducting surface area of 0.2 m2 was heated to 240 ° C, and the interior of the film distillation apparatus Fine was replaced by a nitrogen atmosphere at atmospheric pressure. The solution was supplied to the thin film distillation apparatus via the supply line -21- at the speed of approximately 1200 g / h. A mixed gas containing 3-methyl-1-butanol and 2,4-di-tertamilfenol was extracted from a pipe -25- provided on top of the thin film distillation apparatus -202-, and supplied to a column Distillation -203- filled with the Metal Gauze CY filler (Sulzer Chemtech Ltd., Switzerland). 3-Methyl-1butanol and 2,4-di-tert-amylphenol were separated in the distillation column -203-, and 2,4-di-tert-amylphenol was returned to the top of the distillation apparatus in thin film -202- by means of a pipe -26- provided at the bottom of the distillation column -203-. The reaction liquid was extracted from a pipe -22- provided in the lower part of the thin film distillation apparatus -202- and returned to the feed tank -201- by a pipe -23-.

After performing this step for 62 hours, the reaction liquid was extracted from a pipe -24-. 4532 g of extracted liquid were extracted, and 304 g of solution was recovered from a pipe -27- provided on top of the distillation column -203-.

As a result of the analysis of the reaction liquid extracted by liquid chromatography, it was found that the reaction liquid contained 24.2% by weight of di (2,4-ditert-amylphenyl) ester of N, N'-hexanediyl- acid bis-carbamic. In addition, as a result of the analysis of the solution recovered from the pipeline -27- by 1 H- and 13 C-NMR analysis, the solution was found to contain 98% by weight of 3-methyl-1-butanol. Step (1-4): Production of hexamethylene diisocyanate by thermal decomposition of the di (2,4-di-tert-amylphenyl) ester of N, N’-hexanediyl-bis-carbamic acid

A thermal decomposition reaction was performed in a reaction apparatus as shown in Figure 2.

A thin film distillation apparatus -302- (Kobelco Eco-Solutions Co., Ltd., Japan) having a heat conducting surface area of 0.2 m2 was heated to 200 ° C and the pressure inside the film distillation apparatus Fine was adjusted to approximately 1.3 kPa. The solution obtained in step (1-3) was placed in a feed tank -301- and supplied to the thin film distillation apparatus at a speed of approximately 980 g / h via a pipe -31-. A liquid component was extracted from a pipe -33- provided at the bottom of the thin film distillation apparatus -302- and returned to the feed tank -301- by a pipe -34-. A gaseous component containing hexamethylene diisocyanate and 2,4-di-tert-amylphenol was extracted from a pipe -32- provided on top of a thin film distillation apparatus -302-. The gaseous component was introduced into a distillation column -303- followed by separation into hexamethylene diisocyanate and 2,4di-tert-amylphenol, and a part of 2,4-di-tert-amylphenol was returned to the feed tank -301 - through the pipe -34- through a pipe -36- provided at the bottom of the distillation column -303-. When this reaction was carried out for 13 hours, 266 g of a solution was recovered from a pipeline -35-, and as a result of the analysis of the solution by 1 H- and 13 C-NMR analysis, the solution was found to contain 99% by weight of hexamethylene diisocyanate. The yield based on hexamethylene diamine was 88%. [Example 2] Step (2-1): Production of di (3-methylbutyl) ester of N, N’-hexanediyl-bis-carbamic acid

A solution containing 12.8% by weight of di (3-methylbutyl) ester of N, N'-hexanediyl-bis-carbamic acid was obtained by performing the same method as in step (1-1) of Example 1 with the exception of the addition of 2230 g of 3-methyl-1-butanol to a four-mouth volumetric flask of 5 l and then the addition of 1515 g (7.5 mol) of bis (3-methylbutyl) carbonate and 174 g (1.5 moles) of hexamethylenediamine to this and the use of 28.9 g of sodium methoxide. The solution was passed through a column filled with an ion exchange resin (Amberlyst 15 Dry, Rohm and Haas Co., United States) and 3919 g of solution was recovered. Stage (2-2): Distillation of the low boiling point component

3373 g of a distillate were obtained by performing the same method as in step (1-2) of Example 1 with the exception of using the solution obtained in step (2-1) instead of the solution obtained in step (1-1). As a result of the analysis by gas chromatography, it was found that the distillate contained 27.0% by weight of bis (3-methylbutyl) carbonate and 72.9% by weight of 3-methyl-1-butanol. In addition, as a result of the analysis by liquid chromatography, the distillation residue in the flask was found to contain 92.1% by weight of di (3-methylbutyl) ester of N, N'hexanediyl-bis-carbamic acid. Step (2-3): Production of di (2,4-di-tert-butylphenyl) ester of N, N'-hexanediyl-bis-carbamic acid by transesterification

3351 g of a reaction liquid was extracted from the pipeline -24- using the same method as in step (1-3) of Example 1 with the exception of the use of 544 g of the distillation residue obtained in step (2 -2) instead of the distillation residue obtained in step (1-2), using 92 g of dibutyltin dilaurate, using 2999 g of 2,4-di-tertbutylphenol (Wako Pure Chemical Industries, Ltd., Japan) in place 2,4-di-tert-amylphenol, and performing the reaction for 70 hours. In addition, 246 g of a solution of the pipe -27-provided on top of the distillation column -203- was recovered. The extracted reaction liquid contained 24.2% by weight of di (2,4-di-tert-butylphenyl) ester of N, N’-hexanediyl biscarbamic acid. Step (2-4): Production of hexamethylene diisocyanate by thermal decomposition of di (2,4-di-tert-butylphenyl) ester of N, N’-hexanediyl-bis-carbamic acid

225 g of a pipe solution -35-were recovered by performing the same method as in step (1-4) of Example 1 in a reaction apparatus as shown in Figure 2 with the exception of heating the distillation apparatus in thin film -302- at 200oC, adjusting the pressure inside the thin film distillation apparatus to approximately 1.3 kPa, supplying the solution obtained in step (2-3) to the thin film distillation apparatus at the speed of approximately 980 g / h through the pipeline -31-, and performing the reaction for 11 hours. As a result of the solution analysis by 1 H- and 13 C-NMR analysis, it was found that the solution contained 99% by weight of hexamethylene diisocyanate. The yield based on hexamethylenediamine was 89%. [Example 3] Step (3-1): Production of di (3-methylbutyl) ester of N, N’-hexanediyl-bis-carbamic acid

2754 g of a solution containing 21.6% by weight of di (3-methylbutyl) ester of N, N'hexanediyl bis-carbamic acid were obtained by performing the same method as in step (1-1) of Example 1 with the exception of the use of 2545 g (12.6 mol) of bis (3-methylbutyl) carbonate and 209 g (1.8 mol) of hexamethylenediamine together with the stirrer, and using 3.5 g of sodium methoxide . Stage (3-2): Distillation of the low boiling point component

2150 g of a distillate were obtained by performing the same method as in step (1-2) of Example 1 with the exception of using the solution obtained in step (3-1) instead of the solution obtained in the step (1-1). As a result of the distillate analysis by gas chromatography, it was found that the distillate contained 85.6% by weight of bis (3-methylbutyl) carbonate and 14.0% by weight of 3-methyl-1-butanol. In addition, as a result of the analysis by liquid chromatography, it was found that the distillation residue in the flask contained 98.4% by weight of di (3-methylbutyl) ester of N, N’-hexanediyl-bis-carbamic acid. Step (3-3): Production of di (2,4-di-tert-amylphenyl) ester of N, N’-hexanediyl-bis-carbamic acid by transesterification

4834 g of a reaction liquid were extracted from the pipeline -24- by performing the same method as in step (1-3) of Example 1 with the exception of using 602 g of the distillation residue obtained in step (3 -2) instead of the distillation residue obtained in step (1-2), using 109 g of dibutyltin dilaurate, using 4431 g of 2,4-di-tertamilfenol and performing the reaction for 70 hours. In addition, 297 g of a solution of the pipe -27- provided on top of the distillation column -203- were recovered. The extracted reaction liquid contained 22.2% by weight of di (2,4-ditert-amylphenyl) ester of N, N'-hexanediyl-bis-carbamic acid. Stage (3-4): Distillation of 2,4-di-tert-amylphenol

A vacuum pump and a vacuum controller were attached to a molecular distillation apparatus having a jacketed heating unit driven by oil circulation

(molecular80 molecular distillation apparatus, Asahi Seisakusho Co., Ltd., Japan), and the purge line of the vacuum controller was connected to a gaseous nitrogen pipe. The air inside the molecular distillation apparatus was replaced by nitrogen and the heating unit was heated to 150 ° C with an oil circulator. The pressure in the molecular distillation apparatus was reduced to 0.3 kPa, and the solution obtained in step (3-3) was introduced into the molecular distillation apparatus at the rate of approximately 5 g / minute while the scraper of the molecular distillation apparatus at approximately 300 rpm to distill the 2,4-di-tert-amylphenol. 1291 g of a high boiling substance were recovered in a high boiling sample collector maintained at 120 ° C and as a result of the analysis by liquid chromatography, it was found to contain 83.1% by weight of di ester ( 2,4-di-tert-amylphenyl) of N, N'-hexanediyl-bis-carbamic acid. Step (3-5): Production of hexamethylene diisocyanate by thermal decomposition of di (2,4-di-tert-amylphenyl) ester of N, N’-hexanediyl-bis-carbamic acid

A thermal decomposition reaction was performed in a reaction apparatus as shown in Figure 2.

290 g of a pipe solution -35-were recovered by performing the same method as in step (1-4) of Example 1 with the exception of the introduction of a mixed liquid in the form of a suspension comprising a mixture of 1289 g of the substance containing the carbamic acid ester obtained in step (3-4) and 3422 g of benzylbutyl phthalate (guaranteed reagent, Wako Pure Chemical Industries, Ltd., Japan) in the feed tank -301-, supplying it to the thin film distillation apparatus at the speed of approximately 980 g / h and reacting it for 14 hours. As a result of the solution analysis by 1 H- and 13 C-NMR analysis, it was found that the solution contained 99% by weight of hexamethylene diisocyanate. The yield based on hexamethylene diamine was 83%. [Example 4] Step (4-1): Production of dibutyl ester of N, N’hexanediyl-bis-carbamic acid

A solution containing 30.8% by weight of N, N'-hexanediyl-bis-carbamic acid dibutyl ester was obtained by performing the same method as in step (1-1) of Example 1 with the exception of the use 1479 g (8.5 mol) of dibutyl carbonate produced according to the method of Reference Example 2 and 197 g (1.7 mol) of hexamethylene diamine (Aldrich Corp., United States), and using 3.3 g of methoxide sodium (28% solution in methanol, Wako Pure Chemical Industries, Ltd., Japan) in a 5-liter four-volume volumetric flask. Stage (4-2): Distillation of the low boiling point component

1156 g of a distillate were obtained, performing the same method as in step (1-2) of Example 1 with the exception of using the solution obtained in step (4-1) instead of the solution obtained in the stage (1-1). As a result of the analysis by gas chromatography, it was found that the distillate contained 78.5% by weight of dibutyl carbonate and 20.8% by weight of n-butanol. Furthermore, as a result of the analysis by liquid chromatography, the distillation residue in the flask was found to contain 98.8% by weight of N, N’-hexanediyl-bis-carbamic acid dibutyl ester. Step (4-3): Production of di (2,4-di-tert-amylphenyl) ester of N, N’-hexanediyl-bis-carbamic acid by transesterification

4929 g of a reaction liquid was extracted from the pipeline -24- using the same method as in step (1-3) of Example 1 with the exception of the use of the distillation residue obtained in step (4-2) instead of the distillation residue obtained in step (1-2), using 82 g of dibutyltin dilaurate, adding 4566 g of 2,4-di-tertamilphenol followed by stirring to obtain a homogeneous solution which was then introduced into the feeding tank -201-, heating the thin film distillation apparatus -202- which had a conductive surface area of heat of 0.2 m2 at 240oC and reacting for 86 hours. 233 g of a solution of the pipe -27- provided in the upper part of the distillation column -203- were recovered.

When the extracted reaction liquid was analyzed by liquid chromatography, it was found that the reaction liquid contained 20.4% by weight of di (2,4-di-tertamilphenyl) ester of N, N'-hexanediyl-bis acid -carbamic In addition, when the solution recovered from the pipeline -27- was analyzed by 1 H- and 13 C-NMR analysis, it was found that the solution contained 99.9% by weight of 1-butanol. Step (4-4): Production of hexamethylene diisocyanate by thermal decomposition of di (2,4-di-tert-amylphenyl) ester of N, N’-hexanediyl-bis-carbamic acid

A thermal decomposition reaction was performed in a reaction apparatus as shown in Figure 2.

248 g of a pipe solution -35-were recovered by performing the same method as in step (1-4) of Example 1 with the exception of the use of the solution extracted from the pipe -24- in step (4 -3) instead of the solution extracted from the pipe -24- in step (1-3) and reacting for 14 hours. As a result of the solution analysis by 1 H- and 13 C-NMR analysis, it was found that the solution contained 99% by weight of hexamethylene diisocyanate. The yield based on hexamethylene diamine was 87%. [Example 5] Step (5-1): Production of dibutyl ester of N, N’hexanediyl-bis-carbamic acid

2091 g of a solution containing 26.2% by weight of N, N'-hexanediyl biscarbamic acid dibutyl ester were obtained by performing the same method as in step (1-1) of Example 1 with the exception of using 1879 g (10.8 mol) of dibutyl carbonate and 209 g (1.8 mol) of hexamethylenediamine, adding a stirrer and adding 3.5 g of sodium methoxide. Stage (5-2): Distillation of the low boiling point component

1537 g of a distillate were obtained by performing the same method as in step (1-2) of Example 1 with the exception of using the solution obtained in step (5-1) instead of the solution obtained in step (1-1). As a result of the analysis by gas chromatography, it was found that the distillate contained 82.9% by weight of dibutyl carbonate and 16.6% by weight of n-butanol. Furthermore, as a result of the analysis by liquid chromatography, the distillation residue in the flask was found to contain 99.0% by weight of N, N’-hexanediyl-bis-carbamic acid dibutyl ester. Step (5-3): Production of di, 2,6-dimethylphenyl ester of N, N’-hexanediyl bis-carbamic acid by transesterification

3554 g of a reaction liquid were extracted from the pipeline -24- using the same method as in step (1-3) of Example 1 with the exception of the use of 548 g of the distillation residue obtained in step (5). -2) instead of the distillation residue obtained in step (1-2), using 3142 g of 2,6-dimethylphenol (Aldrich Corp., United States) instead of 2,4-ditert-amylphenol, using 109 g of dilaurate of dibutyltin, adjusting the temperature of the thin film distillation apparatus -202- at 200oC and carrying out the reaction for 225 hours. In addition, 239 g of a solution of the pipe -27-provided on top of the distillation column -203- was recovered. The extracted reaction liquid contained 18.7% by weight of di (2,6-dimethylphenyl) ester of N, N'-hexanediyl-bis-carbamic acid. Step (5-4): Production of hexamethylene diisocyanate by thermal decomposition of di (2,6-dimethylphenyl) ester of N, N’-hexanediyl-bis-carbamic acid

A thermal decomposition reaction was performed in a reaction apparatus as shown in Figure 4.

A thin film distillation apparatus -402- (Kobelco Eco-Solutions Co., Ltd., Japan) having a heat conducting surface area of 0.2 m2 was heated to 200 ° C and the pressure inside the film distillation apparatus Fine was adjusted to approximately 1.3 kPa. The solution obtained in step (5-3) was placed in a feed tank -401- and supplied to the thin film distillation apparatus at the speed of approximately 680 g / h via a pipe -41-. A liquid component was extracted from a pipe -43- provided in the lower part of the thin film distillation apparatus -402- and returned to the feed tank -401- by a pipe -44-. A gaseous component containing hexamethylene diisocyanate and 2,6-dimethylphenol was extracted from a pipe -42- provided on top of the thin film distillation apparatus -402-. The gaseous component was introduced into a distillation column -403- followed by the separation in hexamethylene diisocyanate and 2,6-dimethylphenol, 2,6-dimethylphenol was extracted from a pipe -45- by the top of the column of distillation -403-, and a gaseous component containing hexamethylene diisocyanate was extracted from a pipe -47-provided in the distillation column -403-. On the other hand, a high-boiling substance was extracted from a pipe -46- provided at the bottom of the distillation column, and a part was returned to the feed tank -401- through the pipe -44- . The gaseous component containing hexamethylene diisocyanate extracted from the pipeline -47- was pumped to a distillation column -404-, and the hexamethylene diisocyanate was removed by distillation and separated into the distillation column -404-. A high boiling substance was extracted from a pipe -48- provided in the distillation column -404-, and a part was returned to the feed tank -401- through the pipe -44-. On the other hand, a gaseous component was extracted from a pipe -49-, and hexamethylene diisocyanate was extracted from a pipe -52- by a condenser. After reacting for 11 hours, 249 g of a solution containing 99% by weight of hexamethylene diisocyanate was recovered from the pipeline -47-. The yield based on hexamethylenediamine was 82%. [Example 6] Step (6-1): Production of N, N’hexanediyl-bis-carbamic acid dimethyl ester

A solution containing 39.0% by weight of N, N'-hexanediyl-bis-carbamic acid dimethyl ester therein was obtained by performing the same method as in step (1-1) of Example 1 with the exception of the use of 765 g (8.5 moles) of dimethyl carbonate (Aldrich Corp., United States) and 197 g (1.7 moles) of hexamethylene diamine, and using 3.3 g of sodium methoxide in a volumetric flask of four mouths of 2 l. Stage (6-2): Distillation of the low boiling point component

582 g of a distillate were obtained by performing the same method as in step (1-2) of Example 1 with the exception of using the solution obtained in step (6-1) instead of the solution obtained in step (1-1). As a result of the analysis by gas chromatography, it was found that the distillate contained 80.8% by weight of dimethyl carbonate and 17.9% by weight of methanol. In addition, as a result of the analysis by liquid chromatography, the distillation residue in the flask was found to contain 98.9% by weight of N, N’-hexanediyl-bis-carbamic acid dimethyl ester. Step (6-3): Production of di (2,4-di-tert-amylphenyl) ester of N, N’-hexanediyl-bis-carbamic acid by transesterification

4517 g of a reaction liquid were extracted from the pipeline -24- using the same method as in step (1-3) of Example 1 with the exception of the use of 376 g of the distillation residue in the flask obtained in the step (6-2) instead of the distillation residue in the flask obtained in step (1-2), using 82 g of dibutyltin dilaurate, using 4161 g of 2,4-di-tert-amylphenol and performing the reaction for 86 hours 100 g of a solution of the pipe -27- provided on top of the distillation column -203- were recovered.

When the extracted reaction liquid was analyzed by liquid chromatography, it was found that the reaction liquid contained 22.1% by weight of di (2,4-di-tertamilphenyl) ester of N, N'-hexanediyl-bis acid -carbamic In addition, when the solution recovered from the pipeline -27- was analyzed by 1 H- and 13C-NMR analysis, it was found that the solution contained 99.4% by weight of methanol. Step (6-4): Production of hexamethylene diisocyanate by thermal decomposition of di (2,4-di-tert-amylphenyl) ester of N, N’-hexanediyl-bis-carbamic acid

242 g of a pipe solution -35-were recovered by performing the same method as in step (1-4) of Example 1 with the exception of the use of the solution extracted from the pipe -24- in step (6 -3) instead of the solution extracted from the pipe -24- in step (1-3), and performing the reaction for 13 hours. As a result of the solution analysis by 1 H- and 13 C-NMR analysis, it was found that the solution contained 99% by weight of hexamethylene diisocyanate. The yield based on hexamethylene diamine was 85%. [Example 7] Step (7-1): Production of N, N’hexanediyl-bis-carbamic acid dimethyl ester

934 g of a solution containing 42.4% by weight of N, N'-hexanediyl biscarbamic acid dimethyl ester was obtained by performing the same method as in step (1-1) of Example 1 with the exception of use of 729 g (8.1 mol) of dimethyl carbonate and 209 g (1.8 mol) of hexamethylenediamine, and using 0.35 g of sodium methoxide. Stage (7-2): Distillation of the low boiling point component

533 g of a distillate were obtained by performing the same method as in step (1-2) of Example 1 with the exception of using the solution obtained in step (7-1) instead of the solution obtained in step (1-1). As a result of the analysis by gas chromatography, it was found that the distillate contained 77.8% by weight of dimethyl carbonate and 20.6% by weight of methanol. Furthermore, as a result of the analysis by liquid chromatography, the distillation residue in the flask was found to contain 99.7% by weight of N, N’-hexanediyl-bis-carbamic acid dimethyl ester. Step (7-3): Production of di, 2,6-di-methylphenyl ester of N, N’-hexanediyl-bis-carbamic acid by transesterification

3537 g of a reaction liquid were extracted from the pipeline -24- using the same method as in step (1-3) of Example 1 with the exception of the use of 395 g of the distillation residue obtained in step (7 -2) instead of the distillation residue obtained in step (1-2), using 108 g of dibutyltin dilaurate, using 3133 g of 2,6-dimethylphenol instead of 2,4-di-tert-amylphenol, heating the thin film distillation apparatus -202- at 200oC and carrying out the reaction for 250 hours. In addition, 100 g of a pipe solution -27- provided on top of the distillation column -203- was recovered. The extracted reaction liquid contained 18.3% by weight of di (2,6-di-methylphenyl) ester of N, N'hexanediyl-bis-carbamic acid. Step (7-4): Production of hexamethylene diisocyanate by thermal decomposition of di (2,6-di-methylphenyl) ester of N, N’-hexanediyl-bis-carbamic acid

243 g of a solution containing 99% by weight of hexamethylene diisocyanate was recovered from the pipeline -52- by performing the same method as in step (5-4) of Example 5 with the exception of the use of the reaction liquid obtained from the pipe -24- in step (7-3) instead of the solution obtained in step (5-3), and performing the reaction for 16 hours. The yield with respect to hexamethylenediamine was 81%. [Example 8] Step (8-1): Production of (3-methylbutyl) ester of 3 - ((3-methylbutyl) oxycarbonylamino-methyl) -3,5,5-trimethylcyclohexylcarbamic acid

1980 g (9.8 mol) of bis (3-methylbutyl) carbonate and 239 g (1.8 mol) of 3-aminomethyl-3,5,5-trimethylcyclohexylamine (Aldrich Corp., United States) were placed in a four-volumetric flask 5 l mouths, a stirrer was placed in the flask, and a Dimroth condenser and a three-way valve were attached to the flask. After replacing the interior of the system with nitrogen, the four-mouth flask was immersed in an oil bath (OBH-24, Masuda Corp., Japan) heated to 100 ° C followed by the addition of 2.7 g of sodium methoxide (solution in 28% methanol, Wako Pure Chemical Industries, Ltd., Japan) to start the reaction. The samples of the reaction liquid were properly collected and subjected to NMR analysis, and the reaction was stopped at the point where 3-aminomethyl3,5,5-trimethylcyclohexylamine was no longer detected. As a result of the analysis of the resulting solution by liquid chromatography, it was found that the solution contained 23.9% by weight of (3-methylbutyl) ester of 3- ((3-methylbutyl) oxycarbonylamino-methyl) 3,5,5 -trimethylcyclohexylcarbamic.

Stage (8-2): Distillation of the low boiling point component

1683 g of a distillate were obtained by performing the same method as in step (1-2) of Example 1 with the exception of using the solution obtained in step (8-1) instead of the solution obtained in step (1-1). As a result of the analysis by gas chromatography, it was found that the distillate contained 85.4% by weight of bis (3-methylbutyl) carbonate and 13.8% by weight of 3-methyl-1-butanol. In addition, as a result of the analysis by liquid chromatography, the distillation residue in the flask was found to contain 99.4% by weight of 3- ((3-methylbutyl) oxycarbonylaminomethyl) -3.5 (3-methylbutyl) oxycarbonylaminomethyl) -3.5 , 5-trimethylcyclohexylcarbamic. Step (8-3): Production of 3- ((2,4-di-tert-amylphenyl) oxycarbonylamino-methyl) -3,5,5-trimethylcyclohexylcarbamic acid (2,4-di-tert-amylphenyl) ester by transesterification

5034 g of a reaction liquid were extracted from the pipeline -24- and 221 g of a solution of the pipeline -27- provided at the top of the distillation column -203- was recovered by performing the same method as in the step (1-3) of Example 1 with the exception of the use of 530 g of the distillation residue obtained in step (8-2) instead of the distillation residue obtained in step (1-2), using 84 g of dibutyltin dilaurate, using 4645 g of 2,4-di-tertamilfenol, heating the thin film distillation apparatus -202- to 240oC, supplying the solution to the thin film distillation apparatus via the feed line -21- to the speed of approximately 1200 g / h, and performing the reaction for 75 hours.

When the extracted reaction liquid was analyzed by liquid chromatography, it was found that the reaction liquid contained 17.2% by weight of 3- ((2,4-di-2,4-di-tertamilphenyl) ester -tert-amylphenyl) oxycarbonylaminomethyl) -3,5,5-trimethylcyclohexylcarbamic. In addition, when the solution recovered from the pipeline -27- was analyzed by 1 H- and 13 C-NMR analysis, it was found that the solution contained 99% by weight of 3-methyl-1-butanol. Step (8-4): Production of isophorone diisocyanate by thermal decomposition of 3- ((2,4-di-tert-amylphenyl) oxycarbonylamino-methyl) (2,4-di-tert-amylphenyl) pentyl acid ester - 3,5,5trimethylcyclohexylcarbamic

257 g of a solution containing 99% by weight of isophorone diisocyanate were recovered from the pipeline -52- by performing the same method as in step (5-4) of Example 5 with the exception of heating the distillation apparatus in thin film -402- at 200oC, adjusting the pressure in the thin film distillation apparatus to approximately 1.3 kPa, introducing the solution obtained in step (8-3) into the feed tank -401-, supplying the apparatus of thin film distillation through the pipeline -41- at the speed of approximately 680 g / h, and performing the reaction for 11 hours. The yield based on 3-aminomethyl-3,5,5-trimethylcyclohexylamine was 83%. [Example 9] Step (9-1): Production of butyl ester of 3 (butyloxycarbonylamino-methyl) -3,5,5-trimethylcyclohexylcarbamic acid

The same method as in step (8-1) of Example 8 was performed with the exception of the use of 2349 g (13.5 mol) of dibutyl carbonate, 255 g (1.5 mol) of 3-aminomethyl- 3,5,5trimethylcyclohexylamine and 2.9 g of sodium methoxide. As a result of the analysis of the resulting solution by liquid chromatography, it was found that the solution contained 20.0% by weight of 3- (butyloxycarbonylamino-methyl) -3,5,5-trimethylcyclohexylcarbamic acid butyl ester inside. Stage (9-2): Distillation of the low boiling point component

2075 g of a distillate were obtained by performing the same method as in step (1-2) of Example 1 with the exception of using the solution obtained in step (9-1) instead of the solution obtained in the step (1-1). As a result of the analysis by gas chromatography, it was found that the distillate contained 89.2% by weight of dibutyl carbonate and 10.0% by weight of n-butanol. In addition, as a result of the analysis by liquid chromatography, the distillation residue in the flask was found to contain 98.7% by weight of 3- (butyloxycarbonylamino-methyl) -3,5,5-trimethylcyclohexylcarbamic acid butyl ester. Step (9-3): Production of 3- ((2,4-di-tert-butylphenyl) oxycarbonylamino-methyl) -3,5,5-trimethylcyclohexylcarbamic acid (2,4-di-tert-butylphenyl) ester by transesterification

4077 g of a reaction liquid were extracted from the pipeline -24- and 197 g of a solution of the pipeline -27- provided on top of the distillation column -203- was recovered by performing the same method as in the step (1-3) of Example 1 with the exception of the use of 525 g of the distillation residue obtained in step (9-2), using 89 g of dibutyltin dilaurate, using 3751 g of 2,4-di-tertbutylphenol to obtain a homogeneous solution, by heating the thin film distillation apparatus -202- to 240 ° C, replacing the inside of the thin film distillation apparatus with nitrogen at atmospheric pressure, supplying the solution to the thin film distillation apparatus via the supply -21- at the speed of approximately 1200 g / h and carrying out the reaction for 84 hours.

When the recovered reaction liquid was analyzed by liquid chromatography, it was discovered that the liquid from

reaction

contained he 20.7% in weight from ester (2,4-di-tert

butylphenyl)

of the acid 3 - ((2,4-di-tert

butylphenyl) oxycarbonylamino-methyl) -3,5,5

trimethylcyclohexylcarbamic. In addition, when the solution recovered from the pipeline -27- was analyzed by 1 H- and 13 C-NMR analysis, it was found that the solution contained 98% by weight of 1-butanol. Step (9-4): Production of isophorone diisocyanate by thermal decomposition of 3- ((2,4-di-tert-butylphenyl) oxycarbonylamino-methyl) -3 (2,4-di-tert-butylphenyl) oxycarbonylamino-methyl) -3 , 5.5 trimethylcyclohexylcarbamic

271 g of a solution containing 99% by weight of isophorone diisocyanate were recovered from the pipeline -52- by performing the same method as in step (5-4) of Example 5 with the exception of heating the distillation apparatus in thin film -402- at 200oC, adjusting the pressure in the thin film distillation apparatus to approximately 1.3 kPa, introducing the solution obtained in step (9-3) into the feed tank -401-, supplying the apparatus of thin film distillation through the pipeline -41- at the speed of approximately 680 g / h, and performing the reaction for 11 hours. The yield based on 3-aminomethyl-3,5,5-trimethylcyclohexylamine was 82%.

[Example 10] Step (10-1): Production of butyl ester of 3 (butyloxycarbonylamino-methyl) -3,5,5-trimethylcyclohexylcarbamic acid

A solution containing 25.1% by weight of 3- (butyloxycarbonylamino-methyl) -3,5,5-trimethylcyclohexylcarbamic acid butyl ester was obtained by performing the same method as in step (8-1) of Example 8 with the exception from the use of 1949 g (11.2 mol) of dibutyl carbonate, 272 g (1.6 mol) of 3-aminomethyl-3,5,5-trimethylcyclohexylamine and 3.1 g of sodium methoxide. Stage (10-2): Distillation of the low boiling point component

1657 g of a distillate were obtained by performing the same method as in step (1-2) of Example 1 with the exception of using the solution obtained in step (10-1) instead of the solution obtained in the step (1-1). As a result of the analysis by gas chromatography, it was found that the distillate contained 85.7% by weight of dibutyl carbonate and 13.4% by weight of n-butanol. In addition, as a result of the analysis by liquid chromatography, the distillation residue in the flask was found to contain 98.9% by weight of 3- (butyloxycarbonylamino-methyl) -3,5,5-trimethylcyclohexylcarbamic acid butyl ester. Step (10-3): Production of 3- ((2,4,6-tri-methylphenyl) oxycarbonylamino-methyl) -3,5,5-trimethylcyclohexylcarbamic acid (2,4,6-tri-methylphenyl) ester by transesterification

3067 g of a reaction liquid were extracted from the pipeline -24- and 208 g of a solution of the pipeline -27- provided on top of the distillation column -203- was recovered by performing the same method as in the step (1-3) of Example 1 with the exception of the addition of 76 g of dibutyltin dilaurate to 560 g of the distillation residue obtained in step (10-2), adding 2645 g of 2,4,6-trimethylphenol ( Aldrich Corp., United States) and using them in the form of a homogeneous solution, heating the thin film distillation apparatus -202- to 220oC, replacing the inside of the thin film distillation apparatus with nitrogen at atmospheric pressure, supplying the solution to thin film distillation apparatus via the supply line -21- at the speed of approximately 120 g / h and carrying out the reaction for 180 hours.

When the extracted reaction liquid was analyzed by liquid chromatography, it was discovered that the liquid from

reaction

contained he 22.7% in weight from ester (2,4,6

trimethylphenyl)

of the acid 3 - ((2,4,6-tri

methylphenyl) oxycarbonylamino-methyl) -3,5,5

trimethylcyclohexylcarbamic. In addition, when the solution recovered from the pipeline -27- was analyzed by 1 H- and 13 C-NMR analysis, it was found that the solution contained 99% by weight of 1-butanol. Step (10-4): Production of isophorone diisocyanate by thermal decomposition of 3- ((2,4,6-trimethylphenyl) oxycarbonylamino-methyl) -3,5,5-trimethylcyclohexylcarbamic acid ester (2,4,6-trimethylphenyl)

286 g of a solution containing 99% by weight of isophorone diisocyanate were recovered from the pipeline -52- by performing the same method as in step (5-4) of Example 5 with the exception of heating the distillation apparatus in thin film -402- at 200oC, adjusting the pressure in the thin film distillation apparatus to approximately 1.3 kPa, introducing the solution obtained in step (10-3) into the feed tank -401-, supplying the apparatus of thin film distillation through the pipeline -41- at the speed of approximately 680 g / h, and carrying out the reaction for 14 hours. The yield based on 3-aminomethyl-3,5,5-trimethylcyclohexylamine was 81%. [Example 11] Step (11-1): Production of methyl ester of 3 (methyloxycarbonylamino-methyl) -3,5,5-trimethylcyclohexylcarbamic acid

A solution containing 33.6% by weight of 3- (methyloxycarbonylamino-methyl) -3,5,5-trimethylcyclohexylcarbamic acid methyl ester was obtained by performing the same method as in step (8-1) of Example 8 with the exception from the use of 1323 g (14.7 mol) of dimethyl carbonate, 357 g (2.1 mol) of 3-aminomethyl-3,5,5-trimethylcyclohexylamine and 4.1 g of sodium methoxide. Stage (11-2): Distillation of the low boiling point component

1111 g of a distillate were obtained by performing the same method as in step (1-2) of Example 1 with the exception of using the solution obtained in step (11-1) instead of the solution obtained in the step (1-1). As a result of the analysis by gas chromatography, it was found that the distillate contained 86.7% by weight of dimethyl carbonate and 11.3% by weight of methanol. In addition, as a result of the analysis by liquid chromatography, the distillation residue in the flask was found to contain 99.1% by weight of 3- (methyloxycarbonylamino-methyl) -3,5,5-trimethylcyclohexylcarbamic acid methyl ester. Step (11-3): Production of 3- ((2,4,6-tri-methylphenyl) oxycarbonylaminomethyl) -3,5,5-trimethylcyclohexylcarbamic acid ester (2,4,6-tri-methylphenyl) by transesterification

A transesterification reaction was performed in a reaction apparatus as shown in Figure 2.

4457 g of a reaction liquid were extracted from the pipeline -24- and 118 g of a solution of the pipeline -27- provided on top of the distillation column -203- was recovered by performing the same method as in the step (1-3) of Example 1 with the exception of the addition of 99 g of dibutyltin dilaurate and 4006 g of 2,4,6-trimethylphenol to 567 g of the distillation residue obtained in step (11-2) and using them in the form of a homogeneous solution, by heating the thin film distillation apparatus -202- at 220 ° C, replacing the inside of the thin film distillation apparatus with nitrogen at atmospheric pressure, supplying the solution to the thin film distillation apparatus via the pipe supply -21- at the speed of approximately 1200 g / h and carrying out the reaction for 90 hours.

When the reaction liquid was analyzed by liquid chromatography, it was found that the reaction liquid contained 20.5% by weight ester (2,4,6-trimethylphenyl) of 3- ((2,4,6-) tri-methylphenyl) oxycarbonylamino-methyl) -3,5,5-trimethylcyclohexylcarbamic. In addition, when the solution recovered from the pipeline -27- was analyzed by 1 H- and 13C-NMR analysis, it was found that the solution contained 99% by weight of methanol. Step (11-4): Production of isophorone diisocyanate by thermal decomposition of 3- ((2,4,6-trimethylphenyl) oxycarbonylamino-methyl) -3,5,5-trimethylcyclohexylcarbamic acid ester (2,4,6-trimethylphenyl)

368 g of a solution containing 99% by weight of isophorone diisocyanate from the pipeline -47- were recovered by performing the same method as in step (5-4) of Example 5 with the exception of heating the distillation apparatus in thin film -402- at 200oC, adjusting the pressure in the thin film distillation apparatus to approximately 1.3 kPa, introducing the solution obtained in step (11-3) into the feed tank -401-, supplying the apparatus of thin film distillation through the pipeline -41- at the speed of approximately 900 g / h, and carrying out the reaction for 13 hours. The yield based on 3-aminomethyl-3,5,5-trimethylcyclohexylamine was 79%. [Example 12] Step (12-1): Production of bis (3-methylbutyl) -4,4’methylene-dicyclohexyl carbamate

1313 g (6.5 mol) of bis (3-methylbutyl) carbonate and 273 g (1.3 mol) of 4,4'methylenebis (cyclohexylamine) (Aldrich Corp., United States) were placed in a four-mouth volumetric flask of 5 l, an agitator was placed in the flask, and a Dimroth condenser and a three-way valve were attached to the flask. After replacing the interior of the system with nitrogen, the four-mouth flask was immersed in an oil bath (OBH-24, Masuda Corp., Japan) heated to 100 ° C followed by the addition of 2.5 g of sodium methoxide to start the reaction. The samples of the reaction liquid were properly collected and subjected to NMR analysis, and the reaction was interrupted at the point where 4.4'methylenebis (cyclohexylamine) was no longer detected. As a result of the analysis of the resulting solution by liquid chromatography, it was found that the solution contained 34.3% by weight of bis (3-methylbutyl) -4,4'-methylene-dicyclohexyl carbamate. Stage (12-2): Distillation of the low boiling point component

1034 g of a distillate were obtained by performing the same method as in step (1-2) of Example 1 with the exception of using the solution obtained in step (12-1) instead of the solution obtained in the step (1-1). As a result of the analysis by gas chromatography, it was found that the distillate contained 77.8% by weight of bis (3-methylbutyl) carbonate and 21.2% by weight of 3-methyl-1-butanol. In addition, as a result of the analysis by liquid chromatography, the distillation residue in the flask was found to contain 99.0% by weight of bis (3-methylbutyl) -4,4'-methylenedicyclohexyl carbamate. Step (12-3): Production of bis (2,4-di-tertamilphenyl) -4,4’-methylene-dicyclohexyl carbamate by transesterification

4702 g of a reaction liquid were extracted from the pipeline -24- and 210 g of a solution of the pipeline -27- provided on top of the distillation column -203- was recovered by performing the same method as in the step (1-3) of Example 1 with the exception of the addition of 79 g of dibutyltin dilaurate and 4358 g of 2,4-di-tert-amylphenol to 547 g of the distillation residue obtained in step (12-2) and using them in the form of a homogeneous solution, by heating the thin film distillation apparatus -202- at 260 ° C, replacing the inside of the thin film distillation apparatus with nitrogen at atmospheric pressure, supplying the solution to the thin film distillation apparatus by the supply line -21- at the speed of approximately 1200 g / h and carrying out the reaction for 58 hours.

When the reaction liquid was analyzed by liquid chromatography, it was found that the reaction liquid contained 18.2% by weight of bis (2,4-di-tertamilphenyl) -4,4'-methylene-dicyclohexyl carbamate. In addition, when the solution recovered from the pipeline -27- was analyzed by 1 H- and 13 C-NMR analysis, it was found that the solution contained 99% by weight of 3-methyl-1-butanol. Step (12-4): Production of hexamethylene diisocyanate by thermal decomposition of bis (2,4-di-tert-amylphenyl) 4,4’-methylene-dicyclohexyl carbamate

287 g of a substance containing 99% by weight of 4,4'-methylene di (cyclohexyl isocyanate) were recovered from the pipeline -47- by performing the same method as in step (5-4) of Example 5 with the except for heating the thin film distillation apparatus -402- at 210oC, adjusting the pressure in the thin film distillation apparatus to approximately 0.13 kPa, introducing the solution obtained in step (12-3) into the tank feed -401-, supplying the thin film distillation apparatus via the pipe -41- at the speed of approximately 680 g / h, and carrying out the reaction for 11 hours. The yield based on 4,4’-methylenebis (cyclohexylamine) was 84%. [Example 13] Step (13-1): Production of bis (3-methylbutyl) -4,4’methylene-dicyclohexyl carbamate

A solution containing 29.4% by weight of bis (3-methylbutyl) -4,4'-methylene-dicyclohexyl carbamate was obtained by performing the same method as in step (12-1) of Example 12 with the exception from the use of 1818 g (9.0 mol) of bis (3-methylbutyl) carbonate, 315 g (1.5 mol) of 4,4'methylenebis (cyclohexylamine) and 2.9 g of sodium methoxide. Stage (13-2): Distillation of the low boiling point component

1490 g of a distillate were obtained by performing the same method as in step (1-2) of Example 1 with the exception of using the solution obtained in step (13-1) instead of the solution obtained in the step (1-1). As a result of the analysis by gas chromatography, it was found that the distillate contained 82.6% by weight of bis (3-methylbutyl) carbonate and 16.8% by weight of 3-methyl-1-butanol. In addition, as a result of the analysis by liquid chromatography, the distillation residue in the flask was found to contain 98.0% by weight of bis (3-methylbutyl) -4,4'-methylenedicyclohexyl carbamate. Step (13-3): Production of bis (2,4-di-tertbutylphenyl) -4,4'-methylene-dicyclohexyl carbamate by transesterification

4987 g of a reaction liquid were extracted from the pipeline -24- and 238 g of a solution of the pipeline -27- provided on top of the distillation column -203- was recovered by performing the same method as in the step (1-3) of Example 1 with the exception of the addition of 90 g of dibutyltin dilaurate and 4511 g of 2,4-di-tert-butylphenol to 633 g of the distillation residue obtained in step (13-2) and using them in the form of a homogeneous solution, heating the thin film distillation apparatus -202-to 240 ° C, replacing the inside of the thin film distillation apparatus with nitrogen at atmospheric pressure, supplying the solution to the thin film distillation apparatus by the supply line -21 at the speed of approximately 1200 g / h and carrying out the reaction for 78 hours.

When the reaction liquid was analyzed by liquid chromatography, it was found that the reaction liquid contained 18.3% by weight of bis (2,4-di-tertbutylphenyl) -4,4'-methylene-dicyclohexyl carbamate. In addition, when the solution recovered from the pipeline -27- was analyzed by 1 H- and 13 C-NMR analysis, it was found that the solution contained 99% by weight of 3-methyl-1-butanol. Step (13-4): Production of 4,4’-methylene-di (cyclohexyl isocyanate) by thermal decomposition of bis (2,4-di-tertbutylphenyl) -4,4’-methylene-dicyclohexyl carbamate

325 g of a substance containing 99% by weight of 4,4'-methylene di (cyclohexyl isocyanate) were recovered from the pipe -52- by performing the same method as in step (5-4) of Example 5 with the except for heating the thin film distillation apparatus -402- at 210oC, adjusting the pressure in the thin film distillation apparatus to approximately 0.13 kPa, introducing the solution obtained in step (13-3) into the tank feed -401-, supplying the thin film distillation apparatus via the pipe -41- at the speed of approximately 680 g / h, and carrying out the reaction for 14 hours. The yield based on 4,4’-methylenebis (cyclohexylamine) was 83%. [Example 14] Stage (14-1): Production of dibutyl-4,4’-methylenedicyclohexyl carbamate

A solution containing 29.0% by weight of dibutyl-4,4'-methylene-dicyclohexyl carbamate was obtained by performing the same method as in step (12-1) of Example 12 with the exception of the use of 1696 g (9.8 moles) of dibutyl carbonate, 315 g (1.5 moles) of 4,4'-methylenebis (cyclohexylamine) and 2.9 g of sodium methoxide. Stage (14-2): Distillation of the low boiling point component

1409 g of a distillate were obtained by performing the same method as in step (1-2) of Example 1 with the exception of using the solution obtained in step (14-1) instead of the solution obtained in step (1-1). As a result of the analysis by gas chromatography, it was found that the distillate contained 84.0% by weight of dibutyl carbonate and 14.9% by weight of n-butanol. In addition, as a result of the analysis by liquid chromatography, the distillation residue in the flask was found to contain 97.3% by weight of dibutyl-4,4′-methylene-dicyclohexyl carbamate. Step (14-3): Production of bis (2,6-dimethylphenyl) 4,4’-methylene-dicyclohexyl carbamate by transesterification

3923 g of a reaction liquid were extracted from the pipeline -24- and 194 g of a solution of the pipeline -27- provided on top of the distillation column -203- was recovered by performing the same method as in the step (1-3) of Example 1 with the exception of the addition of 89 g of dibutyltin dilaurate and 3447 g of 2,6-dimethylphenol to 595 g of the distillation residue obtained in step (14-2) and using them in the form of a homogeneous solution, by heating the thin film distillation apparatus -202- at 200 ° C, replacing the inside of the thin film distillation apparatus with nitrogen at atmospheric pressure, supplying the solution to the thin film distillation apparatus via the supply line -21- at the speed of approximately 1200 g / h and performing the reaction for 350 hours.

When the reaction liquid was analyzed by liquid chromatography, it was found that the reaction liquid contained 16.8% by weight of bis (2,6-dimethylphenyl) 4,4′-methylene-dicyclohexyl carbamate. In addition, when the solution recovered from the pipeline -27- was analyzed by 1 H- and 13 C-NMR analysis, it was found that the solution contained 97% by weight of 1-butanol. Step (14-4): Production of 4,4’-methylene-di (cyclohexyl isocyanate) by thermal decomposition of bis (2,6-dimethylphenyl) -4,4’-methylene-dicyclohexyl carbamate

313 g of a solution containing 99% by weight of 4,4'-methylene di (cyclohexyl isocyanate) was recovered from the pipe -52- by performing the same method as in step (5-4) of Example 5 with the except for heating the thin film distillation apparatus -402- at 210oC, adjusting the pressure in the thin film distillation apparatus to approximately 0.13 kPa, introducing the solution obtained in step (14-3) into the tank feed -401-, supplying the thin film distillation apparatus via the pipe -41- at the speed of approximately 700 g / h, and carrying out the reaction for 15 hours. The yield based on 4,4’-methylenebis (cyclohexylamine) was 80%. [Example 15] Step (15-1): Production of dibutyl-4,4’-methylenedicyclohexyl carbamate

A solution containing 27.0% by weight of dibutyl-4,4'-methylene-dicyclohexyl carbamate was obtained by performing the same method as in step (12-1) of Example 12 with the exception of using 1705 g (9.8 moles) of dibutyl carbonate, 294 g (1.4 moles) of 4,4'-methylenebis (cyclohexylamine) and 0.27 g of sodium methoxide (28% methanol solution, Wako Pure Chemical Industries , Ltd.). Stage (15-2): Distillation of the low boiling point component

1643 g of a distillate were obtained by performing the same method as in step (1-2) of Example 1 with the exception of using the solution obtained in step (15-1) instead of the solution obtained in step (1-1). As a result of the analysis by gas chromatography, it was found that the distillate contained 87.7% by weight of dibutyl carbonate and 11.7% by weight of n-butanol. In addition, as a result of the analysis by liquid chromatography, the distillation residue in the flask was found to contain 99% by weight of dibutyl-4,4′-methylene-dicyclohexyl carbamate. Step (15-3): Production of bis (2-tert-butylphenyl) 4,4’-methylene-dicyclohexyl carbamate by transesterification

4256 g of a reaction liquid was extracted from the pipeline -24- and 181 g of a solution of the pipeline -27- provided on top of the distillation column -203- was recovered by performing the same method as in the step (1-3) of Example 1 with the exception of the addition of 84 g of dibutyltin dilaurate and 3980 g of 2-tert-butylphenol to 562 g of the distillation residue obtained in step (15-2) and using them in the form of a homogeneous solution, by heating the thin film distillation apparatus -202- at 220 ° C, replacing the inside of the thin film distillation apparatus with nitrogen at atmospheric pressure, supplying the solution to the thin film distillation apparatus via the supply pipe -21- at the speed of approximately 1200 g / h and carrying out the reaction for 180 hours.

When the reaction liquid was analyzed by liquid chromatography, it was found that the reaction liquid contained 15.5% by weight of bis (2-tert-butylphenyl) 4,4’-methylene-dicyclohexyl carbamate. In addition, when the solution recovered from the pipeline -27- was analyzed by 1 H- and 13 C-NMR analysis, it was found that the solution contained 99% by weight of 1-butanol. Stage (15-4): Production of 4,4’-methylene-di (cyclohexyl isocyanate) by thermal decomposition of bis (2-tertbutylphenyl) -4,4’-methylene-dicyclohexyl carbamate

287 g of a solution containing 99% by weight of 4,4'-methylene di (cyclohexyl isocyanate) was recovered from the pipe -52- by performing the same method as in step (5-4) of Example 5 with the except for heating the thin film distillation apparatus -402- at 210oC, adjusting the pressure in the thin film distillation apparatus to approximately 0.13 kPa, introducing the solution obtained in step (15-3) into the tank feed -401-, supplying the thin film distillation apparatus via the pipe -41- at the speed of approximately 710 g / h, and carrying out the reaction for 14 hours. The yield based on 4,4’-methylenebis (cyclohexylamine) was 78%. [Example 16] Step (16-1): Production of dimethyl-4,4’-methylenedicyclohexyl carbamate

A solution containing 28.2% by weight of dimethyl-4,4'-methylene-dicyclohexyl carbamate was obtained by performing the same method as in step (1-1) of Example 1 with the exception of the use of 1440 g (16.0 moles) of dimethyl carbonate, 336 g (1.6 moles) of 4,4'-methylenebis (cyclohexylamine) and 1.5 g of sodium methoxide (28% methanol solution, Wako Pure Chemical Industries , Ltd.). Stage (16-2): Distillation of the low boiling point component

1271 g of a distillate were obtained by performing the same method as in step (1-2) of Example 1 with the exception of using the solution obtained in step (16-1) instead of the solution obtained in step (1-1). As a result of the analysis by gas chromatography, it was found that the distillate contained 91.3% by weight of dimethyl carbonate and 7.7% by weight of methanol. In addition, as a result of the analysis by liquid chromatography, the distillation residue in the flask was found to contain 99.4% by weight of dibutyl-4,4′-methylene-dicyclohexyl carbamate. Step (16-3): Production of bis (2,4-di-tertamilphenyl) -4,4’-methylene-dicyclohexyl carbamate by transesterification

5151 g of a reaction liquid was extracted from the pipeline -24- and 88 g of a solution from the pipeline -27- provided on top of the distillation column -203- was recovered by performing the same method as in the step (1-3) of Example 1 with the exception of the addition of 97 g of dibutyltin dilaurate and 4645 g of 2,4-di-tert-amylphenol to 501 g of the distillation residue obtained in step (16-2) and using them in the form of a homogeneous solution, heating the thin film distillation apparatus -202- to 240oC, replacing the inside of the thin film distillation apparatus with nitrogen at atmospheric pressure, supplying the solution to the thin film distillation apparatus by the supply line -21- at the speed of approximately 1200 g / h and carrying out the reaction for 80 hours.

When the reaction liquid was analyzed by liquid chromatography, it was found that the reaction liquid contained 19.5% by weight of bis (2,4-di-tertamphenyl) -4,4'-methylene-dicyclohexyl carbamate. In addition, when the solution recovered from the pipeline -27- was analyzed by 1 H- and 13C-NMR analysis, it was found that the solution contained 99% by weight of methanol. Stage (16-4): Production of 4,4’-methylene-di (cyclohexyl isocyanate) by thermal decomposition of bis (2,4-di-tertamilphenyl) -4,4’-methylene-dicyclohexyl carbamate

The same method was performed as in step (5-4) of Example 5 with the exception of heating the thin film distillation apparatus -402- to 210 ° C, by adjusting the pressure in the thin film distillation apparatus to approximately 0, 13 kPa, introducing the solution obtained in step (16-3) into the feed tank -401-, supplying the thin film distillation apparatus via the pipeline -41- at the speed of approximately 680 g / h, and performing the reaction for 16 hours. 323 g of a solution containing 99% by weight of 4,4′-methylene di (cyclohexyl isocyanate) was recovered from the pipeline -52-. The yield based on 4,4’-methylenebis (cyclohexylamine) was 77%. [Example 17] Step (17-1): Production of bis (3-methylbutyl) ester of toluene-2,4-dicarbamic acid

1818 g (9.0 moles) of bis (3-methylbutyl) carbonate and 220 g (1.8 moles) of 2,4-toluenediamine (Aldrich Corp., United States) were placed in a 5-liter four-mouth volumetric flask , an agitator was placed in the flask, and a Dimroth condenser and a three-way valve were attached to the flask. After replacing the interior of the system with nitrogen, the four-mouth flask was immersed in an oil bath (OBH-24, Masuda Corp., Japan) heated to 80 ° C, followed by the addition of 0.35 g of sodium methoxide ( 28% methanol solution, Wako Pure Chemical Industries, Ltd.) to start the reaction. Samples of the reaction liquid were properly collected and subjected to NMR analysis, and the reaction was stopped at the point where 2,4-toluenediamine was no longer detected. As a result of the analysis of the resulting solution by liquid chromatography, it was found that the solution contained 29.7% by weight of bis (3-methylbutyl) ester of toluene-2,4-dicarbamic acid. Stage (17-2): Distillation of the low boiling point component

1422 g of a distillate were obtained by performing the same method as in step (1-2) of Example 1 with the exception of using the solution obtained in step (17-1) instead of the solution obtained in step (1-1). As a result of the analysis by gas chromatography, it was found that the distillate contained 78.2% by weight of bis (3-methylbutyl) carbonate and 21.2% by weight of 3-methyl-1-butanol. In addition, as a result of the analysis by liquid chromatography, it was found that the distillation residue in the flask contained 98.0% by weight of bis (3-methylbutyl) ester of toluene-2,4-dicarbamic acid. Step (17-3): Production of bis (2,4-di-tert-amylphenyl) ester of toluene-2,4-dicarbamic acid by transesterification

5258 g of a reaction liquid was extracted from the pipeline -24- and 289 g of a solution of the pipeline -27- provided on top of the distillation column -203- was recovered by performing the same method as in the step (1-3) of Example 1 with the exception of the addition of 109 g of dibutyltin dilaurate and 4835 g of 2,4-di-tert-amylphenol to 615 g of the distillation residue obtained in step (17-2) and using them in the form of a homogeneous solution, heating the thin film distillation apparatus -202- to 240oC, replacing the inside of the thin film distillation apparatus with nitrogen at atmospheric pressure, supplying the solution to the thin film distillation apparatus by the supply line -21- at the speed of approximately 1200 g / h and carrying out the reaction for 70 hours.

When the reaction liquid was analyzed by liquid chromatography, it was found that the reaction liquid contained 20.0% by weight of bis (2,4-di-tert-amylphenyl) ester of toluene-2,4-dicarbamic acid . In addition, when the solution recovered from the pipeline -27- was analyzed by 1 H- and 13 C-NMR analysis, it was found that the solution contained 98% by weight of 3-methyl-1-butanol. Step (17-4): Production of toluene-2,4-diisocyanate by thermal decomposition of bis (2,4-di-tert-amylphenyl) ester of toluene-2,4-dicarbamic acid

The same method was performed as in step (1-4) of Example 1 with the exception of heating the thin film distillation apparatus -302- at 200 ° C, adjusting the pressure in the thin film distillation apparatus to approximately 1, 3 kPa, introducing the solution obtained in step (17-3) into the feed tank -301-, supplying the thin film distillation apparatus through the pipeline -31- at the speed of approximately 1000 g / h, and performing The reaction for 15 hours. 267 g of a solution was recovered from the pipeline -35-, and as a result of the solution analysis by 1 H- and 13 C-NMR analysis, it was found that the solution contained 99% by weight of toluene-2,4- diisocyanate The yield based on 2,4-toluenediamine was 85%. [Example 18] Stage (18-1): Production of N, N ’- (4,4’ methanediyl diphenyl) -biscarbamic acid dibutyl ester

1774 g (10.2 mol) of dibutyl carbonate and 336 g (1.7 mol) of 4,4'-methylenedianiline (Aldrich Corp., United States) were placed in a four-mouth volumetric flask of 5 l, He placed a stirrer in the flask, and a Dimroth condenser and a three-way valve were attached to the flask. After replacing the interior of the system with nitrogen, the four-mouth flask was immersed in an oil bath (OBH-24, Masuda Corp., Japan) heated to 80 ° C followed by the addition of 3.3 g of sodium methoxide (solution in 28% methanol, Wako Pure Chemical Industries, Ltd.) to start the reaction. The samples of the reaction liquid were properly collected and subjected to NMR analysis, and the reaction was stopped at the point where 4,4'-methylenedianiline was no longer detected. As a result of the analysis of the resulting solution by liquid chromatography, it was found that the solution contained 30.8% by weight of N, N ′ - (4,4’-methanediyl diphenyl) biscarbamic acid dibutyl ester. Stage (18-2): Distillation of the low boiling point component

1452 g of a distillate were obtained by performing the same method as in step (1-2) of Example 1 with the exception of using the solution obtained in step (18-1) instead of the solution obtained in the step (1-1). As a result of the analysis by gas chromatography, it was found that the distillate contained 82.7% by weight of dibutyl carbonate and 16.6% by weight of 1-butanol. Furthermore, as a result of the analysis by liquid chromatography, the distillation residue in the flask was found to contain 98.5% by weight of N, N '- (4,4'-methanediyl diphenyl) dibutyl ester) - biscarbamic Step (18-3): Production of bis (2,4-di-tert-amylphenyl) ester of N, N ’- (4,4’-methanediyl-diphenyl) -biscarbamic acid by transesterification

4322 g of a reaction liquid were extracted from the pipeline -24- and 226 g of a solution of the pipeline -27- provided on top of the distillation column -203- was recovered by performing the same method as in the step (1-3) of Example 1 with the exception of the addition of 103 g of dibutyltin dilaurate and 3799 g of 2,4-di-tert-amylphenol to 656 g of the distillation residue obtained in step (18-2) and using them in the form of a homogeneous solution, heating the thin film distillation apparatus -202- to 240oC, replacing the inside of the thin film distillation apparatus with nitrogen at atmospheric pressure, supplying the solution to the thin film distillation apparatus by the supply line -21- at the speed of approximately 1200 g / h and carrying out the reaction for 62 hours.

When the reaction liquid was analyzed by liquid chromatography, it was found that the reaction liquid contained 25.3% by weight of bis (2,4-di-tert-amylphenyl) ester of N, N '- (4 , 4'-methanediyl diphenyl) -biscarbamic. In addition, when the solution recovered from the pipeline -27- was analyzed by 1 H- and 13 C-NMR analysis, it was found that the solution contained 99% by weight of 1-butanol. Step (18-4): Production of 4,4'-diphenylmethane diisocyanate by thermal decomposition of bis (2,4-di-tertamilphenyl) ester of N, N '- (4,4'-methanediyl diphenyl) - biscarbamic

When the thin-film distillation apparatus -402-was heated to 210 ° C, the pressure in the thin-film distillation apparatus was adjusted to approximately 0.1 kPa, the solution obtained in step (18-3) was introduced into the feed tank -401-, was supplied to the thin film distillation apparatus via the pipe -41- at the speed of approximately 680 g / h, and the reaction was carried out for 11 hours, 351 g of a solution containing 99% by weight of 4,4'-diphenylmethane diisocyanate of the pipeline -52-. The yield based on 4,4'-methylenedianiline was 83%. [Example 19] Stage (19-1): Production of N, N ’- (4,4’ methanediyl diphenyl) -biscarbamic acid dibutyl ester

A solution containing 26.7% by weight of N, N '- (4,4'-methanediyl diphenyl) -biscarbamic acid dibutyl ester was obtained by performing the same method as in step (18-1) of Example 18 with the exception of the use of 1583 g (9.1 mol) of dibutyl carbonate, 257 g (1.3 mol) of 4,4'methylenedianiline and 2.5 g of sodium methoxide (28% methanol solution , Wako Pure Chemical Industries, Ltd.).

Stage (19-2): Distillation of the low boiling point component

1342 g of a distillate were obtained by performing the same method as in step (1-2) of Example 1 with the exception of using the solution obtained in step (19-1) instead of the solution obtained in the step (1-1). As a result of the analysis by gas chromatography, it was found that the distillate contained 85.5% by weight of dibutyl carbonate and 13.6% by weight of 1-butanol. Furthermore, as a result of the analysis by liquid chromatography, it was discovered that the distillation residue in the flask contained 98.6% by weight of N, N '- (4,4'-methanediyl diphenyl) dibutyl ester - biscarbamic Step (19-3): Production of bis, 2,6-dimethylphenyl ester of N, N ’- (4,4’-methanediyl diphenyl) -biscarbamic acid by transesterification

2824 g of a reaction liquid were extracted from the pipeline -24- and 160 g of a solution of the pipeline -27- provided on top of the distillation column -203- was recovered by performing the same method as in the step (1-3) of Example 1 with the exception of the addition of 74 g of dibutyltin dilaurate and 2441 g of 2,6-dimethylphenol to 475 g of the distillation residue obtained in step (19-2) and using them in the form of a homogeneous solution, by heating the thin film distillation apparatus -202- at 200 ° C, replacing the inside of the thin film distillation apparatus with nitrogen at atmospheric pressure, supplying the solution to the thin film distillation apparatus via the supply line -21- at the speed of approximately 1200 g / h and performing the reaction for 662 hours.

When the reaction liquid was analyzed by liquid chromatography, it was found that the reaction liquid contained 18.9% by weight of bis (2,6-dimethylphenyl) ester of toluene-2,4-dicarbamic acid. In addition, when the solution recovered from the pipeline -27- was analyzed by 1 H- and 13 C-NMR analysis, it was found that the solution contained 99% by weight of 1-butanol. Step (19-4): Production of 4,4’-diphenylmethane diisocyanate by thermal decomposition of bis (2,6-dimethylphenyl) ester of N, N ’- (4,4’-methanediyl diphenyl) -biscarbamic acid

244 g of a solution containing 99% by weight of 4,4'-diphenylmethane diisocyanate were recovered from the pipe -52- by performing the same method as in step (5-4) of Example 5 with the exception of heating of the thin film distillation apparatus -402- at 210oC, adjusting the pressure in the thin film distillation apparatus to approximately 0.1 kPa, introducing the solution obtained in step (19-3) into the feed tank -401 -, supplying the thin film distillation apparatus via the pipe -41- at the speed of approximately 700 g / h, and carrying out the reaction for 13 hours. The yield based on 4,4'-methylenedianiline was 75%. [Example 20] Stage (20-1): Production of N, N'hexanediyl-bis-carbamic acid dibutyl ester

A solution containing 22.7% by weight of N, N'-hexanediyl-bis-carbamic acid dibutyl ester was obtained by performing the same method as in step (1-1) of Example 1 with the exception of the use 2192 g (12.6 mol) of dibutyl carbonate, 209 g (1.8 mol) of hexamethylenediamine and 3.5 g of sodium methoxide (28% methanol solution, Wako Pure Chemical Industries, Ltd.). Stage (20-2): Distillation of the low boiling point component

1845 g of a distillate were obtained by performing the same method as in step (1-2) of Example 1 with the exception of using the solution obtained in step (20-1) instead of the solution obtained in step (1-1). As a result of the analysis by gas chromatography, it was found that the distillate contained 85.9% by weight of dibutyl carbonate and 13.6% by weight of 1-butanol. In addition, as a result of the analysis by liquid chromatography, it was found that the distillation residue in the flask contained 98.6% by weight of N, N ′ - (hexanodiyl) -bis-carbamic acid dibutyl ester. Step (20-3): Production of di (2,6-di-tert-butylphenyl) ester of N, N'-hexanediyl-bis-carbamic acid by transesterification

5395 g of a reaction liquid was extracted from the pipeline -24- and 206 g of a solution of the pipeline -27- provided on top of the distillation column -203- was recovered by performing the same method as in the step (1-3) of Example 1 with the exception of obtaining a homogeneous solution of 550 g of the distillation residue obtained in step (20-3), 109 g of dibutyltin dilaurate and 4950 g of 2,6-di-tert -butylphenol, heating the thin film distillation apparatus -202- at 240oC, and performing the reaction for 86 hours.

When the reaction liquid was analyzed by liquid chromatography, it was found that the reaction liquid contained 14.9% by weight of di (2,6-di-tert-butylphenyl) ester of N, N'-hexanediyl- acid bis-carbamic. In addition, when the solution recovered from the pipeline -27- was analyzed by 1H- and 13C-NMR analysis, it was found that the solution contained 99% by weight of 1butanol. Step (20-4): Production of hexamethylene diisocyanate by thermal decomposition of di (2,6-di-tert-butylphenyl) ester of N, N’-hexanediyl-bis-carbamic acid

The same method as in step (1-4) of Example 1 was performed with the exception of heating the thin film distillation apparatus -302-which was heated to 200 ° C, adjusting the pressure in the thin film distillation apparatus to approximately 1.3 kPa, introducing the solution obtained in step (20-3) that was introduced into the feed tank -301-, supplying the thin film distillation apparatus via the pipe -31- at the speed of approximately 980 g / h, and performing the reaction for 13 hours. 210 g of a solution was recovered from the pipe -35-. As a result of the solution analysis by 1 H- and 13 C-NMR analysis, it was found that the solution contained 99% by weight of hexamethylene diisocyanate. The yield based on hexamethylene diamine was 70%. [Example 21] Step (21-1): Production of di (3-methylbutyl) ester of N, N’-hexanediyl-bis-carbamic acid

A solution containing 24.0% by weight of di (3-methylbutyl) ester of N, N'-hexanediyl-bis-carbamic acid was obtained by performing the same method as in step (1-1) of Example 1 with the exception of the use of 2290 g (11.3 mol) of bis (3-methylbutyl) carbonate, 208.8 g (1.8 mol) of hexamethylenediamine and 3.5 g of sodium methoxide (solution in methanol at 28 %, Wako Pure Chemical Industries, Ltd.). Stage (21-2): Distillation of the low boiling point component

1891 g of a distillate were obtained by performing the same method as in step (1-2) of Example 1 with the exception of using the solution obtained in step (21-1) instead of the solution obtained in step (1-1). As a result of the analysis by gas chromatography, it was found that the distillate contained 83.6% by weight of bis (3-methylbutyl) carbonate and 16.1% by weight of 3-methyl-1-butanol. In addition, as a result of the analysis by liquid chromatography, the distillation residue in the flask was found to contain 98.6% by weight of di (3-methylbutyl) ester of N, N'hexanediyl-bis-carbamic acid. Step (21-3): Production of di (2-phenylphenyl) ester of N, N’-hexanediyl-bis-carbamic acid by transesterification

3977 g of a reaction liquid were extracted from the pipeline -24- and 276 g of a solution of the pipeline -27- provided on top of the distillation column -203- was recovered by performing the same method as in the step (1-3) of Example 1 with the exception of the addition of 110 g of dibutyltin dilaurate and 3545 g of 2-phenylphenol to 606 g of the distillation residue obtained in step (21-2) and using them in the form of a homogeneous solution, heating the thin film distillation apparatus -202- to 240oC, replacing the inside of the thin film distillation apparatus with atmospheric pressure nitrogen, supplying the solution to the thin film distillation apparatus via the supply line -21 - at the speed of approximately 1200 g / h and performing the reaction for 80 hours.

When the reaction liquid was analyzed by liquid chromatography, it was found that the reaction liquid contained 20.0% by weight of di (2-phenylphenyl) ester of N, N’-hexanediyl-bis-carbamic acid. In addition, when the solution recovered from the pipeline -27- was analyzed by 1 H- and 13 C-NMR analysis, it was found that the solution contained 99% by weight of 3-methyl-1-butanol. Step (21-4): Production of hexamethylene diisocyanate by thermal decomposition of di (2-phenylphenyl) ester of N, N’hexanediyl-bis-carbamic acid

241 g of a pipe solution -35-were recovered by performing the same method as in step (1-4) of Example 1 with the exception of heating the thin film distillation apparatus -302- at 200 ° C, adjusting the pressure in the thin film distillation apparatus at approximately 1.3 kPa, introducing the solution obtained in step (21-3) into the feed tank -301-, supplying the thin film distillation apparatus via the pipe -31- at the rate of approximately 980 g / h, and performing the reaction for 13 hours. As a result of the solution analysis by 1 H and 13 C-NMR analysis, it was found that the solution contained 99% by weight of hexamethylene diisocyanate. The yield based on hexamethylenediamine was 80%. [Example 22] Step (22-1): Production of di (3-methylbutyl) ester of N, N’-hexanediyl-bis-carbamic acid

A solution containing 23.8% by weight of di (3-methylbutyl) ester of N, N'-hexanediyl-bis-carbamic acid was obtained by performing the same method as in step (1-1) of Example 1 with the exception of the use of 2163 g (10.7 mol) of bis (3-methylbutyl) carbonate, 197 g (1.7 mol) of hexamethylenediamine and 3.3 g of sodium methoxide (28% methanol solution, Wako Pure Chemical Industries, Ltd.). Stage (22-2): Distillation of the low boiling point component

1783 g of a distillate were obtained by performing the same method as in step (1-2) of Example 1 with the exception of using the solution obtained in step (22-1) instead of the solution obtained in step (1-1). As a result of the analysis by gas chromatography, it was found that the distillate contained 83.5% by weight of bis (3-methylbutyl) carbonate and 16.0% by weight of 3-methyl-1-butanol. In addition, as a result of the analysis by liquid chromatography, the distillation residue in the flask was found to contain 97.1% by weight of di (3-methylbutyl) ester of N, N'hexanediyl-bis-carbamic acid.

Step (22-3): Production of di (2,4-bis (, dimethylbenzyl) phenyl) ester of N, N’-hexanediyl-bis-carbamic acid by transesterification

4689 g of a reaction liquid were extracted from the pipeline -24- and 259 g of a solution of the pipeline -27- provided on top of the distillation column -203- was recovered by performing the same method as in the step (1-3) of Example 1 with the exception of the addition of 103 g of dilaurate of

dibutyltin and 4385 g of 2,4-bis (, -dimethylbenzyl) phenol (Aldrich Corp., United States) at 575 g of the distillation residue obtained in step (22-2) and using them in the form of a homogeneous solution , by heating the thin film distillation apparatus -202- to 240 ° C, replacing the inside of the thin film distillation apparatus with nitrogen at atmospheric pressure, supplying the solution to the thin film distillation apparatus via the supply line -21- a the speed of approximately 1200 g / h and performing the reaction for 80 hours.

When the reaction liquid was analyzed by liquid chromatography, it was found that the reaction liquid contained 25.8% by weight of di (2,4-bis (, dimethylbenzyl) phenyl) ester of N, N 'acid -hexanodiyl-bis-carbamic. In addition, when the solution recovered from the pipeline -27- was analyzed by 1 H- and 13 C-NMR analysis, it was found that the solution contained 99% by weight of 3-methyl-1-butanol. Stage (22-4): Production of hexamethylene diisocyanate by

thermal decomposition of di (2,4-bis (, dimethylbenzyl) phenyl) ester of N, N’-hexanediyl-bis-carbamic acid

220 g of a pipe solution -35-were recovered by performing the same method as in step (1-4) of Example 1 with the exception of heating the thin film distillation apparatus -302- at 200oC, adjusting the pressure in the thin film distillation apparatus at approximately 1.3 kPa, introducing the solution obtained in step (22-3) into the feed tank -301-, supplying the thin film distillation apparatus via the pipe -31- at the rate of approximately 980 g / h, and performing the reaction for 18 hours. As a result of the solution analysis by 1 H and 13 C-NMR analysis, it was found that the solution contained 99% by weight of hexamethylene diisocyanate. The yield based on hexamethylenediamine was 77%. [Example 23]

Hexamethylene diisocyanate was produced in an apparatus

reaction as shown in figure 5. Stage (23-1): Production process of di (3-methylbutyl) ester of N, N’-hexanediyl-bis-carbamic acid

A stirring tank -601- (internal volume: 5 l) was heated to 80oC. Bis (3-methylbutyl) carbonate was transferred to the stirring tank -601- from a pipe -60- at the speed of 678 g / h with a closed -62- pipe, and a mixed solution of hexamethylenediamine, 3-methyl- 1-butanol and sodium methoxide (28% solution in methanol) (mixing ratio: 50 parts hexamethylenediamine / 50 parts 3-methyl-1-butanol / 0.42 parts sodium methoxide) was transferred simultaneously from a pipe -61- to the speed of 112 g / h. After 4 hours, the pipe -62- was opened with a closed -63- pipe, and the transfer of the reaction liquid to a tank -602- at the speed of 790 g / h was started. The pipe -62- was maintained at 80 ° C to prevent precipitation of solids from the reaction liquid.

When the reaction liquid transferred to a pipeline -602- was analyzed by liquid chromatography, it was found that the reaction liquid contained 20.3% by weight of di (3-methylbutyl) ester of N, N'-hexanediyl-bis acid -carbamic Stage (23-2): Distillation process of the low boiling component

A thin film distillation apparatus -603- (heat conducting surface area of 0.2 m2, Kobelco Eco-Solutions Co., Ltd., Japan) was heated to 150 ° C and the pressure inside the apparatus was adjusted to approximately 0, 02 kPa

The solution stored in the tank -602- was transferred to the thin film distillation apparatus -603- of the pipeline -63- at the speed of 790 g / h where a low boiling component contained in the solution was removed by distillation. The low boiling component that had been removed by distillation was removed from the thin film distillation apparatus -603- by a pipe -64-. On the other hand, a high boiling component was extracted from the thin film distillation apparatus -603- by a pipe -65- maintained at 150oC, and transferred to a stirring tank -604- maintained at 120oC. At the same time, 2,4-di-tert-amylphenol was transferred via a pipe -66- to the stirring tank -604- at the speed of 1306 g / h, and dibutyltin dilaurate was transferred to a stirring tank -604 - through a pipeline -67- at the speed of 29 g / h.

The mixed liquid prepared in the agitation tank -604- was transferred to a tank -605- through a pipe 68 with a closed pipe -69-, and stored in the tank -605-. When the solution stored in the tank -605- was analyzed by liquid chromatography, it was found that the solution contained 10.7% by weight of di (3-methylbutyl) ester of N, N'hexanediyl-bis-carbamic acid. Step (23-3): Production process of di (2,4-di-tertamilphenyl) ester of N, N’-hexanediyl-bis-carbamic acid by transesterification

A thin film distillation apparatus -606- (heat conducting surface area of 0.2 m2, Kobelco Eco-Solutions Co., Ltd., Japan) was heated to 240 ° C.

A transesterification reaction was performed by transferring a mixed liquid of di (3-methylbutyl) ester of N, N'-hexanediyl-bis-carbamic acid, 2,4-di-tert-amylphenol and dibutyltin dilaurate by storing in the tank -605 - to the thin film distillation apparatus -606- through a pipe -69- at the speed of 1496 g / h with a pipe -72- closed. A mixed gas containing 3-methyl-1-butanol and 2,4-di-tert-amylphenol was extracted from a pipe -73- provided on top of the thin film distillation apparatus -606-, and supplied to a distillation column -607-. The 3-methyl-1-butanol and 2,4-ditert-amylphenol were separated in the distillation column -607-, and the 2,4-di-tert-amylphenol was returned to the top of the distillation apparatus in thin film -606- by means of a pipe -74- provided at the bottom of the distillation column -607-. A reaction liquid was extracted from a pipe -70-provided in the lower part of the thin film distillation apparatus -606-, and was supplied to the thin film distillation apparatus -606- by a pipe -71-. When the di (2,4-di-tert-amylphenyl) ester of N, N'-hexanediyl biscarbamic acid in the reaction liquid extracted from the pipe -70-reached 20.3% by weight, the pipe -72 - opened with the pipeline -75- closed and the reaction liquid was transferred to a tank -608-. Step (23-4): Production process of hexamethylene diisocyanate by thermal decomposition of di (2,4-di-tertamilphenyl) ester of N, N’-hexanediyl-bis-carbamic acid

The solution stored in the tank -608- was supplied to a thin film distillation apparatus -609- (0.2 m2 heat conducting surface area, Kobelco Eco-Solutions Co., Ltd., Japan) heated to 200oC and adjusted to an internal pressure of approximately 1.3 kPa through the pipe -75- at the speed of 1395 g / h. A gaseous component containing hexamethylene diisocyanate was extracted from a pipe -77-provided on top of the thin film distillation apparatus -609- and supplied to a distillation column -610-. The distillation separation was carried out in the distillation column -610-, and hexamethylene diisocyanate was recovered from a pipe -79- at the rate of 72 g / h. [Comparative Example 1] Stage (A-1): Production of N, N’hexanediyl-bis-carbamic acid dimethyl ester

1044 g of a solution containing 29.6% by weight of N, N'-hexanediyl biscarbamic acid methyl ester were obtained by performing the same method as in step (1-1) of Example 1 with the exception of use of 882 g (9.8 mol) of dimethyl carbonate and 162 g (1.4 mol) of hexamethylene diamine, adding a stirrer, and using 2.7 g of sodium methoxide. Stage (A-2): Distillation of the low boiling point component

729 g of a distillate was obtained by performing the same method as in step (1-2) of Example 1 with the exception of using the solution obtained in step (A-1) instead of the solution obtained in the step (1-1). As a result of the analysis by gas chromatography, it was found that the distillate contained 87.5% by weight of dimethyl carbonate and 11.7% by weight of methanol. As a result of the analysis by liquid chromatography, the distillation residue in the flask was found to contain 98.2% by weight of N, N’-hexanediyl-bis-carbamic acid dimethyl ester. Step (A-3): Production of diphenyl ester of N, N’hexanediyl-bis-carbamic acid by transesterification

4101 g of a reaction liquid were extracted from the pipeline -24- and 65 g of a solution of the pipeline -27- provided on top of the distillation column -203- was recovered by performing the same method as in the step (1-3) of Example 1 with the exception of using 316 g of the distillation residue obtained in step (A-2) instead of the distillation residue obtained in step (1-2), using 85 g of dibutyltin dilaurate and 3770 g of phenol (for nucleic acid extraction, Wako Pure Chemical Industries, Ltd., Japan), adjusting the heating unit of the thin film distillation apparatus at 180 ° C and performing the reaction for 430 hours. The extracted reaction liquid contained 8.7% by weight of diphenyl ester of N, N'-hexanediyl-bis-carbamic acid. Step (A-4): Production of hexamethylene diisocyanate by thermal decomposition of diphenyl ester of N, N’hexanediyl-bis-carbamic acid

The same method was performed as in step (5-4) of Example 5 with the exception of heating the thin film distillation apparatus -402- at 200 ° C, by adjusting the pressure inside the thin film distillation apparatus to approximately 1, 3 kPa, introducing the solution obtained in step (A-3) into the feed tank -401-, supplying the thin film distillation apparatus through the pipeline -41- at the speed of approximately 680 g / h, and performing The reaction for 11 hours. 134 g of a solution containing 99% by weight of hexamethylene diisocyanate were recovered from the pipeline -47-. The yield based on hexamethylene diamine was 57%. In addition, a black solid adhered to the side walls of the thin film distillation apparatus -402- after step (A-4) was completed. [Comparative Example 2] Stage (B-1): Production of di (3-methylbutyl) ester of N, N’-hexanediyl-bis-carbamic acid

2146 g of a solution containing 23.1% by weight of di (3-methylbutyl) ester of N, N'hexanediyl bis-carbamic acid were obtained by performing the same method as in step (1-1) of Example 1 with the exception of the use of 1970 g (9.8 mol) of bis (3-methylbutyl) carbonate and 174 g (1.5 mol) of hexamethylenediamine, adding a stirrer, and using 2.9 g of sodium methoxide . Stage (B-2): Distillation of the low boiling point component

1631 g of a distillate were obtained by performing the same method as in step (1-2) of Example 1 with the exception of using the solution obtained in step (B-1) instead of the solution obtained in the step (1-1). As a result of the analysis by gas chromatography, it was found that the distillate contained 84.2% by weight of bis (3-methylbutyl) carbonate and 15.4% by weight of 3-methyl-1-butanol. In addition, as a result of the analysis by liquid chromatography, the distillation residue in the flask was found to contain 96.7% by weight of bis (3-methylbutyl) ester of N, N'hexanediyl-bis-carbamic acid. Step (B-3): Production of di (4-methylphenyl) ester of N, N’-hexanediyl-bis-carbamic acid by transesterification

4978 g of a reaction liquid were extracted from the pipeline -24- and 185 g of a solution of the pipeline -27- provided on top of the distillation column -203- was recovered by performing the same method as in the step (1-3) of Example 1 with the exception of the use of 510 g of the distillation residue obtained in step (B-2) instead of the distillation residue obtained in step (1-2), using 91 g of dibutyltin dilaurate and 4645 g of 4-methylphenol (Aldrich Corp., United States), and performing the reaction for 58 hours. The extracted reaction liquid contained 8.1% by weight of di (4-methylphenyl) ester of N, N'-hexanediyl-bis-carbamic acid. Step (B-4): Production of hexamethylene diisocyanate by thermal decomposition of di (4-methylphenyl) ester of N, N’hexanediyl-bis-carbamic acid

A thermal decomposition reaction was performed in a reaction apparatus as shown in Figure 4.

The thin film distillation apparatus -402- (Kobelco Eco-Solutions Co., Ltd., Japan) having a heat conducting surface area of 0.2 m2 was heated to 200 ° C and the pressure inside the film distillation apparatus Fine was adjusted to approximately 1.3 kPa. The solution obtained in step (B-3) was introduced into the feed tank -401- and supplied to the thin film distillation apparatus via the pipeline -41- at the speed of approximately 680 g / h. A liquid component was extracted from the pipe -43- provided in the lower part of the thin film distillation apparatus -402-, and returned to the feed tank -401- by the pipe -44-. A gaseous component containing hexamethylene diisocyanate and 4-methylphenol was extracted from the pipe -42- provided on top of the thin film distillation apparatus -402-. The gaseous component was introduced into the distillation column -403- where hexamethylene diisocyanate and 4methylphenol were separated, 4-methylphenol was extracted from the pipe -45- connected to the top of the distillation column -403-, hexamethylene diisocyanate was extracted from the pipeline -47- provided in an intermediate phase of the distillation column -403-, a high boiling substance was extracted from the pipeline -46- provided at the bottom of the column of distillation -403-, and a part was returned to the feed tank -401- through the pipeline -44-. When the reaction was carried out for 11 hours, 114 g of a solution containing 99% by weight of hexamethylene diisocyanate were recovered from the pipeline -47-. The yield based on hexamethylene diamine was 57%. In addition, a black solid adhered to the side walls of the thin film distillation apparatus -402- after step (B-4) was completed. [Comparative Example 3] Stage (C-1): Production of N, N’hexanediyl-bis-carbamic acid dibutyl ester

1818 g (10.5 mol) of dibutyl carbonate produced using the method of Reference Example 2 and 220 g (1.9 mol) of hexamethylenediamine were placed in a 5-liter four-volume volumetric flask, a stirrer was placed in the flask, and a Dimroth condenser and a three-way valve were attached to the flask. After replacing the interior of the system with nitrogen, the four-mouth flask was immersed in an oil bath (OBH-24, Masuda Corp.) heated to 80 ° C, followed by the addition of 3.7 g of sodium methoxide (solution in 28% methanol, Wako Pure Chemical Industries, Ltd.) to start the reaction. Samples of the reaction liquid were properly collected and subjected to NMR analysis, and the reaction was interrupted at the point where hexamethylenediamine was no longer detected. As a result of the analysis of the resulting solution by liquid chromatography, it was found that the solution contained 28.3% by weight of N, N’-hexanediyl-bis-carbamic acid dibutyl ester. Stage (C-2): Distillation of the low boiling point component

1444 g of a distillate were obtained by performing the same method as in step (1-2) of Example 1 with the exception of using the solution obtained in step (C-1) instead of the solution obtained in the step (1-1). As a result of the analysis by gas chromatography, it was found that the distillate contained 80.9% by weight of dibutyl carbonate and 18.6% by weight of 1-butanol. Furthermore, as a result of the analysis by liquid chromatography, the distillation residue in the flask was found to contain 98.0% by weight of N, N’-hexanediyl-bis-carbamic acid dibutyl ester. Step (C-3): Production of di (4-octylphenyl) ester of N, N’-hexanediyl-bis-carbamic acid by transesterification

6122 g of a reaction liquid was extracted from the pipeline -24- and 182 g of a solution of the pipeline -27- provided on top of the distillation column -203- was recovered by performing the same method as in the step (1-3) of Example 1 with the exception of the use of 594 g of the distillation residue obtained in step (6-3) instead of the distillation residue obtained in step (1-2), adding 114 g of dibutyltin dilaurate and 5611 g of 4-octylphenol and using them in the form of a homogeneous solution, introducing it into the feed tank -201-, heating the thin film distillation apparatus -202- which had a heat conducting surface area of 0 , 2 m2 at 240oC, and performing the reaction for 86 hours.

When the extracted reaction liquid was analyzed by liquid chromatography, it was found that the reaction liquid contained 11.5% by weight of di (4-octylphenyl) ester of N, N’-hexanediyl-bis-carbamic acid. In addition, when the solution recovered from the pipeline -27- was analyzed by 1 H- and 13 C-NMR analysis, it was found that the solution contained 99.0% by weight of 1-butanol. Step (C-4): Production of hexamethylene diisocyanate by thermal decomposition of di (4-octylphenyl) ester of N, N’hexanediyl-bis-carbamic acid

A thermal decomposition reaction was performed in a reaction apparatus as shown in Figure 3.

The thin film distillation apparatus -302- having a heat conducting surface area of 0.2 m2 was heated to 200 ° C and the pressure inside the thin film distillation apparatus was adjusted to approximately 1.3 kPa. The solution obtained in step (C-3) was introduced into the feed tank -301- and was supplied to the thin film distillation apparatus via the pipe -31- at the speed of approximately 980 g / h. A liquid component was extracted from the pipe -33- provided at the bottom of the thin film distillation apparatus -302-, and returned to the feed tank -301- by the pipe -34-. A gaseous component containing hexamethylene diisocyanate and 4-octylphenol was extracted from the pipe -32- provided on top of the thin film distillation apparatus -302-. The gaseous component was introduced into the distillation column -303- where the hexamethylene diisocyanate and 4octylphenol were separated, and a part of 4-octylphenol was returned to the feed tank -301- through the pipe -34- through the pipe -36- provided at the bottom of the distillation column -303-. When the reaction was carried out for 13 hours, 167 g of a solution was recovered from the pipeline -35-, and as a result of the solution analysis by 1 H- and 13 C-NMR analysis, the solution was found to contain 99% by weight of hexamethylene diisocyanate. The yield based on hexamethylenediamine was 53%. In addition, a black solid adhered to the side walls of the thin film distillation apparatus -302- once stage (C-4) was completed. [Comparative Example 4] Stage (D-1): Production of N, N’hexanediyl-bis-carbamic acid dibutyl ester

1914 g (11.0 moles) of dibutyl carbonate produced using the method of Reference Example 2 and 232 g (2.0 moles) of hexamethylenediamine were placed in a 5-liter four-volume volumetric flask, a stirrer was placed in the flask, and a Dimroth condenser and a three-way valve were attached to the flask. After replacing the interior of the system with nitrogen, the four-mouth flask was immersed in an oil bath heated to 80 ° C followed by the addition of 0.37 g of sodium methoxide (28% methanol solution, Wako Pure Chemical Industries, Ltd.) to start the reaction. Samples of the reaction liquid were properly collected and subjected to NMR analysis, and the reaction was interrupted at the point where hexamethylenediamine was no longer detected. As a result of the analysis of the resulting solution by liquid chromatography, it was found that the solution contained 28.3% by weight of N, N’-hexanediyl-bis-carbamic acid dibutyl ester. Stage (D-2): Distillation of the low boiling point component

1532 g of a distillate were obtained by performing the same method as in step (1-2) of Example 1 with the exception of using the solution obtained in step (D-1) instead of the solution obtained in the step (1-1). As a result of the analysis by gas chromatography, it was found that the distillate contained 80.9% by weight of dibutyl carbonate and 18.5% by weight of 1-butanol. Furthermore, as a result of the analysis by liquid chromatography, it was found that the distillation residue in the flask contained 99.5% by weight of N, N’-hexanediyl-bis-carbamic acid dibutyl ester. Step (D-3): Production of di (3-octyloxy) ester of N, N’hexanediyl-bis-carbamic acid by transesterification

4203 g of a reaction liquid were extracted from the pipeline -24- and 250 g of a solution from the pipeline -27- provided on top of the distillation column -203- was recovered by performing the same method as in the step (1-3) of Example 1 with the exception of using 605 g of the distillation residue obtained in step (6-3) instead of the distillation residue obtained in step (1-2), adding 120 g of dibutyltin dilaurate and 3727 g of 3-octanol (Aldrich Corp., United States) and using it in the form of a homogeneous solution, introducing it into the feed tank -201-, heating the thin film distillation apparatus -202- that it had a conductive surface area of heat of 0.2 m2 at 175oC, and carrying out the reaction for 180 hours.

When the extracted reaction liquid was analyzed by liquid chromatography, it was found that the reaction liquid contained 17.1% by weight of di (3-octyloxy) ester of N, N’-hexanediyl-bis-carbamic acid. In addition, when the solution recovered from the pipeline -27- was analyzed by 1 H- and 13 C-NMR analysis, it was found that the solution contained 99.0% by weight of 1-butanol. Step (D-4): Production of hexamethylene diisocyanate by thermal decomposition of di (3-octyloxy) ester of N, N’hexanediyl-bis-carbamic acid

A thermal decomposition reaction was performed in a reaction apparatus as shown in Figure 4.

The thin film distillation apparatus -402- (Kobelco Eco-Solutions Co., Ltd., Japan) having a heat conducting surface area of 0.2 m2 was heated to 200 ° C and the pressure inside the film distillation apparatus Fine was adjusted to approximately 1.3 kPa. The solution obtained in step (D-3) was introduced into the feed tank -401- and was supplied to the thin film distillation apparatus via the pipeline -41- at the speed of approximately 680 g / h. A liquid component was extracted from the pipe -43- provided in the lower part of the thin film distillation apparatus -402-, and returned to the feed tank -401- by the pipe -44-. A gaseous component containing hexamethylene diisocyanate and 3-octanol was extracted from the pipe -42- provided on top of the thin film distillation apparatus -402-. The gaseous component was introduced into the distillation column -403- where the hexamethylene diisocyanate and 3octanol were separated, the 3-octanol was extracted from the pipe -45-connected to the top of the distillation column -403-, hexamethylene diisocyanate was removed from the pipeline -47- provided in an intermediate phase of the distillation column -403-, a high boiling substance was extracted from the pipeline -46- provided in the lower part of the distillation column -403-, and a part was returned to the feed tank -401-through the pipe -44-. When the reaction was carried out for 11 hours, 149 g of a solution containing 99% by weight of hexamethylene diisocyanate were recovered from the pipeline -47-. The yield based on hexamethylenediamine was 45%. In addition, a black solid adhered to the side walls of the thin film distillation apparatus -402- after step (D-4) was completed. Industrial applicability

Since the isocyanate production process according to the present invention makes it possible to efficiently produce isocyanates without using the extremely toxic phosgene, the production process of the present invention is extremely useful from an industrial point of view and has a high commercial value.

Claims (9)

1. Process for producing an isocyanate, comprising the steps of: reacting a carbamic acid ester and a compound 5 aromatic hydroxy to obtain an aryl carbamate having a group derived from the aromatic hydroxy compound; and subjecting the aryl carbamate to a decomposition reaction, wherein the aromatic hydroxy compound is an aromatic hydroxy compound that is represented by the following 10 formula (1) and having a substituent R1, at least, in an ortho position of a hydroxyl group: image 1 wherein ring A represents an aromatic hydrocarbon ring in the form of a single or multiple rings that 15 may have a substituent and having 6 to 20 carbon atoms; R1 represents a different group of a hydrogen atom in the form of an aliphatic alkyl group having 1 to 20 carbon atoms, an aliphatic alkoxy group having 1 to 20 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, an aryloxy group having 6 to 20 carbon atoms, an aralkyl group having 7 to 20 carbon atoms or an aralkyloxy group having 7 to 20 carbon atoms, the group containing an atom selected from a 25 carbon atom, an oxygen atom and a nitrogen atom; and R1 can join A to form a ring structure. 2. A process according to claim 1, wherein the aromatic hydroxy compound is a compound represented by the following formula (2): wherein the ring A and R1 are the same as defined above, R2 represents an atom of hydrogen or an aliphatic alkyl group image 1 5 having 1 to 20 carbon atoms, an aliphatic alkoxy group having 1 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, an aryloxy group having 6 to 20 carbon atoms , an aralkyl group having 7 to 20 carbon atoms or an aralkyloxy group having 7 to 20 atoms, 10 containing the aliphatic alkyl, aliphatic alkoxy, aryl, aryloxy, aralkyl and aralkyloxy groups an atom selected from a carbon atom, an oxygen atom and a nitrogen atom, and R2 can be attached to A to form a ring structure. 3. Process according to claim 2, wherein in the In formula (2), a total number of carbon atoms constituting R1 and R2 is from 2 to 20. 4. Process according to any one of claims 1 to 3, wherein the ring A of the aromatic hydroxy compound comprises a structure containing at least one structure 20 selected from the group consisting of a benzene ring, a naphthalene ring and an anthracene ring. 5. Process according to claim 4, wherein the aromatic hydroxy compound is a compound represented by the following formula (3): image2 wherein R1 and R2 are the same as defined above, and each of R3, R4 and R5 independently represents a hydrogen atom or an aliphatic alkyl group having 1 to 20 carbon atoms, an aliphatic alkoxy group which it has 1 to 20 carbon atoms, an aryl group that has 6 to 20 carbon atoms, an aryloxy group that has 6 to 20 carbon atoms, a group 5 aralkyl having 7 to 20 carbon atoms or an aralkyloxy group having 7 to 20 carbon atoms, the groups containing aliphatic alkyl, aliphatic alkoxy, aryl, aryloxy, aralkyl and aralkyloxy containing an atom selected from a carbon atom, an oxygen atom and a nitrogen atom. 6. Process according to claim 5, wherein the aromatic hydroxy compound is such that in formula (3), each of R1 and R4 independently represents a group represented by the following formula (4), and R2, R3 and R5 represent a hydrogen atom: image3 in which X represents a branched structure selected from the structures represented by the following formulas (5) and (6): image 1 In which R6 represents a linear or branched alkyl group having 1 to 3 carbon atoms. 7. Process according to claim 5, wherein the aromatic hydroxy compound is such that in formula (3), R1 represents a linear or branched alkyl group having from 1 to 8 25 carbon atoms, and each of R2 and R4 independently represents a hydrogen atom or a linear alkyl group or branched having 1 to 8 carbon atoms. 8. A process according to any one of claims 1 to 7, wherein the carbamic acid ester is an aliphatic carbamic acid ester, and a low boiling component formed with the aryl carbamate is an aliphatic alcohol. Process according to claim 8, wherein the aliphatic carbamic acid ester is an aliphatic polycarbamic acid ester. 10. Process according to claim 8, further comprising the steps of: 10 continuously supplying the aliphatic carbamic acid ester and the aromatic hydroxy compound to a reaction vessel to react to the aliphatic carbamic acid ester and the aromatic hydroxy compound within the reaction vessel; Recovering a low boiling component formed in the form of a gaseous component; and continuously extracting a reaction liquid containing aryl carbamate and the aromatic hydroxy compound from a lower part of the reaction vessel. A process according to any one of claims 1 to 10, wherein the decomposition reaction is a thermal decomposition reaction, and is a reaction in which a corresponding isocyanate and an aromatic hydroxy compound are formed from the carbamate of aryl 12. A process according to claim 11, wherein at least one isocyanate compound and aromatic hydroxy compound formed by the thermal decomposition reaction of aryl carbamate is recovered as a gaseous component. 13. A process according to claim 8, wherein the aliphatic carbamic acid ester is a compound represented by the following formula (7): image 1 in which R7 represents a group selected from the group composed of an aliphatic group having 1 to 20 carbon atoms and an aromatic group having 6 to 20 carbon atoms, the group containing an atom selected from a carbon atom, an oxygen atom and a nitrogen atom, and having 5 a valence of n, R8 represents an aliphatic group having 1 to 8 carbon atoms and containing an atom selected from a carbon atom, an oxygen atom and a nitrogen atom, and n represents an integer from 1 to 10. 14. Process according to claim 13, wherein the aliphatic carbamic acid ester is such that R8 in the compound represented by the formula (7) is a group selected from the group consisting of an alkyl group having from 1 to 20 carbon atoms and a cycloalkyl group having 5 to 20 atoms of 15 carbon 15. Process according to claim 14, wherein the aliphatic carbamic acid ester is at least one compound selected from the group consisting of compounds represented by the following formulas (8), (9) and (10): image4 wherein R8 is a group selected from the group consisting of an alkyl group having 1 to 20 carbon atoms and a cycloalkyl group having 5 to 20 carbon atoms.