JP5563887B2 - Carbonate processing method - Google Patents

Description

  The present invention relates to a method for treating carbonate, and more particularly, to a method for treating carbonate such as dialkyl carbonate, diaryl carbonate, and alkylaryl carbonate.

  Carbonates such as dialkyl carbonates, diaryl carbonates and alkylaryl carbonates are used as various industrial raw materials, and industrially react with amines, urea and / or N-unsubstituted carbamic acid esters and alcohols (carbamates). It is known as a by-product when a carbamate is produced by reaction.

  For example, an organic polyamine, urea and alcohol are reacted in the presence of a dialkyl carbonate, alkyl carbamate to give a polyurethane (carbamate), while from the reaction mixture containing the resulting polyurethane (carbamate), the alcohol, dialkyl carbonate There has been proposed a method of removing nates and alkyl carbamates and recycling them to the reaction step of organic polyamine, urea and alcohol (see, for example, Patent Document 1).

  In this method, an organic polyamine, urea and alcohol are reacted to obtain a polyurethane (carbamate) as a main product, while a dialkyl carbonate and alkyl carbamate obtained as a by-product are reacted with an organic polyamine, urea and alcohol. In this case, a dialkyl carbonate and an organic polyamine are separately reacted to form polyurethane (carbamate).

JP-A-6-25136

  However, in the above reaction, carbonates such as dialkyl carbonates obtained as by-products are significantly inferior in reactivity to amines compared to urea and N-unsubstituted carbamic acid esters. Even if dialkyl carbonate is recycled, it is difficult to industrially produce polyurethane (carbamate) efficiently.

  On the other hand, industrially, it is desired to effectively use various carbonates containing such by-products.

  The objective of this invention is providing the processing method of carbonate for utilizing carbonate efficiently.

  In order to achieve the above object, the method for treating carbonate according to the present invention is to decompose at least one carbonate selected from the group consisting of dialkyl carbonate, diaryl carbonate and alkylaryl carbonate into alcohol by contacting with high pressure high temperature water. It is characterized by doing.

  In the carbonate treatment method of the present invention, it is preferable to obtain the carbonate by a carbamation reaction between an amine, urea and / or an N-unsubstituted carbamic acid ester, and an alcohol.

  In the carbonate treatment method of the present invention, the carbonate is preferably obtained by further coarsely separating the carbonate from a low-boiling component containing N-unsubstituted carbamic acid ester and carbonate separated after the carbamate reaction. It is.

  In the carbonate treatment method of the present invention, it is preferable that the carbonate contains an N-unsubstituted carbamic acid ester.

  In the carbonate treatment method of the present invention, it is preferable to use the alcohol obtained by decomposing the carbonate as a raw material component for the carbamate reaction.

  In the carbonate treatment method of the present invention, it is preferable that the N-unsubstituted carbamic acid ester is roughly separated from the low-boiling component and used as a raw material component for the carbamate reaction.

  According to the method for treating carbonate of the present invention, since carbonate can be decomposed into alcohol, carbonate can be used industrially effectively.

It is a schematic block diagram which shows one Embodiment of the plant by which the processing method of the carbonate of this invention is employ | adopted.

  In the carbonate processing method of the present invention, the carbonate is brought into contact with high-pressure and high-temperature water to decompose into alcohol.

  As the carbonate, at least one selected from the group consisting of dialkyl carbonate, diaryl carbonate and alkylaryl carbonate is used.

  The dialkyl carbonate is represented by the following general formula (1), for example.

R ¹ OCOOR ² (1)
(In the formula, R ¹ and R ² are the same or different from each other and represent an alkyl group.)
In the above formula (1), examples of the alkyl group represented by R ¹ and R ² include methyl, ethyl, n-propyl, iso-propyl, n-butyl, iso-butyl, sec-butyl, tert-butyl, C1-C8 linear or branched saturated hydrocarbon groups such as pentyl, hexyl, heptyl, octyl, iso-octyl, 2-ethylhexyl, for example, C5-C10 fats such as cyclohexyl and cyclododecyl Examples thereof include cyclic saturated hydrocarbon groups.

  More specifically, as such a dialkyl carbonate, for example, symmetric dialkyl carbonate such as dimethyl carbonate, diethyl carbonate, di (n-) propyl carbonate, di (n-) butyl carbonate, dicyclohexyl carbonate, dicyclododecyl carbonate, Examples include asymmetric dialkyl carbonates such as methyl ethyl carbonate, methyl (n-) propyl carbonate, ethyl (n-) propyl carbonate, methyl cyclohexyl carbonate, and cyclohexyl cyclododecyl carbonate.

  The diaryl carbonate is represented by the following general formula (2), for example.

R ³ OCOOR ⁴ (2)
(In the formula, R ³ and R ⁴ are the same or different from each other and each represents an aryl group which may have a substituent.)
In the above formula (2), examples of the aryl group which may have a substituent represented by R ³ and R ⁴ include 6 to 6 carbon atoms such as phenyl, tolyl, xylyl, biphenyl, naphthyl, anthryl and phenanthryl. 18 aryl groups are mentioned. Examples of the substituent include a hydroxyl group, a halogen atom (eg, chlorine, fluorine, bromine and iodine), a cyano group, an amino group, a carboxyl group, an alkoxy group (eg, methoxy, ethoxy, propoxy, butoxy, etc.) Alkoxy groups having 1 to 4 carbon atoms, etc.), aryloxy groups (for example, phenoxy groups, etc.), alkylthio groups (for example, alkylthio groups having 1 to 4 carbon atoms such as methylthio, ethylthio, propylthio, butylthio, etc.) and arylthio groups (For example, a phenylthio group etc.) etc. are mentioned. Further, when a substituent is substituted with a plurality of aryl groups, each substituent may be the same as or different from each other.

  More specifically, examples of such diaryl carbonates include symmetric diaryl carbonates such as diphenyl carbonate, ditolyl carbonate, and dixylyl carbonate, for example, asymmetric diaryl carbonates such as phenyltolyl carbonate and phenylxylyl carbonate. .

  The alkylaryl carbonate is represented by, for example, the following general formula (3).

R ⁵ OCOOR ⁶ (3)
(In the formula, R ⁵ represents an alkyl group, and R ⁶ represents an aryl group which may have a substituent.)
In the above formula (3), examples of the alkyl group represented by R ⁵ include the above-described alkyl groups.

In the above formula (3), examples of the aryl group which may have a substituent represented by R ⁶ include an aryl group which may have the above-described substituent.

  More specific examples of such alkyl aryl carbonates include methyl phenyl carbonate, ethyl phenyl carbonate, methyl tolyl carbonate, and methyl xylyl carbonate.

  These carbonates can be used alone or in combination of two or more.

  As the carbonate, dialkyl carbonate is preferably used.

  In this invention, carbonate can be manufactured by a well-known method, for example, and a commercial item can also be used for it.

  And in order to make carbonate contact high pressure high temperature water, while supplying carbonate in a well-known pressure-resistant heat-resistant tank, high pressure high temperature water is supplied.

  The high-pressure high-temperature water is pressurized to a high pressure, that is, 3 to 30 MPa, preferably 6 to 25 MPa, more preferably 6 to 20 MPa, and high temperature, that is, 190 to 350 ° C., preferably 200 to 300 ° C. Heated water that is heated and pressurized by known methods.

  In addition, the decomposition pressure (inside tank pressure) of carbonate is 3 to 30 MPa, preferably 6 to 25 MPa, and more preferably 6 to 20 MPa. Moreover, the decomposition temperature (inside tank temperature) of carbonate is 190-350 degreeC, Preferably, it is 200-300 degreeC.

  Moreover, as high-pressure high-temperature water, a hydrolysis ratio (mass ratio of high-pressure high-temperature water / carbonate) is controlled to, for example, 0.5 to 30, preferably 1 to 15.

  As a result, the carbonate is hydrolyzed by high-pressure and high-temperature water, and as a decomposition product, a corresponding alcohol, more specifically, an alcohol represented by the following general formula (4) is generated, and carbon dioxide and the like are by-produced. To do.

R ⁷ -OH (4)
(In the formula, R ⁷ represents R ¹ or R ^{2 in} the above formula (1), R ³ or R ^{4 in} the above formula (2), R ⁵ or R ^{6 in} the above formula (3).)
In such a carbonate treatment method, for example, as a by-product in a reaction (carbamation reaction) in which a carbamate is obtained by reacting an amine, urea and / or N-unsubstituted carbamic acid ester, and an alcohol. The resulting carbonate can also be used.

  By using the carbonate obtained as a by-product in the carbamate reaction, the carbonate can be effectively used.

  In the carbamation reaction, the amine includes, for example, a primary amine.

  The primary amine is an amino group-containing organic compound having one or more primary amino groups, and is represented by, for example, the following general formula (5).

_{^{R 8 - (NH 2) n}} (5)
(In the formula, R ⁸ is an aliphatic hydrocarbon group having 1 to 15 carbon atoms in total, an alicyclic hydrocarbon group having 3 to 15 carbon atoms, or an aromatic ring-containing hydrocarbon group having 6 to 15 carbon atoms in total. N represents an integer of 1 to 6.)
In the above formula (5), R ⁸ contains an aliphatic hydrocarbon group having 1 to 15 carbon atoms in total, an alicyclic hydrocarbon group having 3 to 15 carbon atoms in total, and an aromatic ring containing 6 to 15 carbon atoms in total. Selected from hydrocarbon groups. R ⁸ may contain a stable bond such as an ether bond, a thioether bond or an ester bond in the hydrocarbon group, or may be substituted with a stable functional group (described later). Good.

In R ⁸ , examples of the aliphatic hydrocarbon group having 1 to 15 carbon atoms in total include 1 to 6-valent linear or branched aliphatic hydrocarbon groups having 1 to 15 carbon atoms in total. .

In the above formula (5), examples of the primary amine in which R ⁸ is an aliphatic hydrocarbon group having 1 to 15 carbon atoms include aliphatic amines having 1 to 15 carbon atoms.

  Examples of such aliphatic amines include methylamine, ethylamine, n-propylamine, iso-propylamine, butylamine, pentylamine, hexylamine, n-octylamine, 2-ethylhexylamine, decylamine, dodecylamine, tetra Linear or branched aliphatic primary monoamines such as decylamine, such as 1,2-diaminoethane, 1,3-diaminopropane, 1,4-diaminobutane (1,4-tetramethylenediamine), 1 , 5-diaminopentane (1,5-pentamethylenediamine), 1,6-diaminohexane (1,6-hexamethylenediamine), 1,7-diaminoheptane, 1,8-diaminooctane, 1,9-diaminononane 1,10-diaminodecane, 1,12-diaminododecane, , 2,4-trimethylhexamethylenediamine, 2,4,4-trimethylhexamethylenediamine, aliphatic primary diamine such as tetramethylenediamine, for example, 1,2,3-triaminopropane, triaminohexane, triamino Nonane, triaminododecane, 1,8-diamino-4-aminomethyloctane, 1,3,6-triaminohexane, 1,6,11-triaminoundecane, 3-aminomethyl-1,6-diaminohexane, etc. And aliphatic primary triamines.

In R ⁸ , examples of the alicyclic hydrocarbon group having 3 to 15 carbon atoms include 1 to 6-valent alicyclic hydrocarbon groups having 3 to 15 carbon atoms.

  The alicyclic hydrocarbon group only needs to contain one or more alicyclic hydrocarbons in the hydrocarbon group. For example, the alicyclic hydrocarbon includes, for example, an aliphatic hydrocarbon group. Etc. may be combined. In such a case, the amino group in the primary amine may be directly bonded to the alicyclic hydrocarbon, or may be bonded to the aliphatic hydrocarbon group bonded to the alicyclic hydrocarbon. Or both.

In the above formula (5), examples of the primary amine in which R ⁸ is an alicyclic hydrocarbon group having 3 to 15 carbon atoms include alicyclic amines having 3 to 15 carbon atoms.

  Examples of such alicyclic amines include alicyclic primary monoamines such as cyclopropylamine, cyclobutylamine, cyclopentylamine, cyclohexylamine, and hydrogenated toluidine, such as diaminocyclobutane, isophoronediamine (3-aminomethyl- 3,5,5-trimethylcyclohexylamine), 1,2-diaminocyclohexane, 1,3-diaminocyclohexane, 1,4-diaminocyclohexane, 1,3-bis (aminomethyl) cyclohexane, 1,4 -Bis (aminomethyl) cyclohexane, 4,4'-methylenebis (cyclohexylamine), 2,5-bis (aminomethyl) bicyclo [2,2,1] heptane, 2,6-bis (aminomethyl) bicyclo [ 2,2,1] heptane, hydrogenated 2,4-tolylenediamine, water Alicyclic primary diamines, such as 2,6-tolylenediamine, for example, an alicyclic primary triamine such as triamino-cyclohexane.

In R ⁸ , examples of the aromatic ring-containing hydrocarbon group having 6 to 15 carbon atoms include 1 to 6-valent aromatic ring-containing hydrocarbon groups having 6 to 15 carbon atoms in total.

  The aromatic ring-containing hydrocarbon group only needs to contain one or more aromatic hydrocarbons in the hydrocarbon group. For example, the aromatic hydrocarbon includes, for example, an aliphatic hydrocarbon group. It may be bonded. In such a case, the amino group in the primary amine may be directly bonded to the aromatic hydrocarbon, or may be bonded to the aliphatic hydrocarbon group bonded to the aromatic hydrocarbon. Both may be used.

In the above formula (5), examples of the primary amine in which R ⁸ is an aromatic ring-containing hydrocarbon group having 6 to 15 carbon atoms include aromatic amines having 6 to 15 carbon atoms and 6 to 15 carbon atoms. And araliphatic amines.

  Examples of such aromatic amines include aniline, o-toluidine (2-methylaniline), m-toluidine (3-methylaniline), p-toluidine (4-methylaniline), 2,3-xylidine (2 , 3-dimethylaniline), 2,4-xylidine (2,4-dimethylaniline), 2,5-xylidine (2,5-dimethylaniline), 2,6-xylidine (2,6-dimethylaniline), 3 Aromatic primary monoamines such as 1,4-xylidine (3,4-dimethylaniline), 3,5-xylidine (3,5-dimethylaniline), 1-naphthylamine, 2-naphthylamine, for example, 2,4-tolylene Amine (2,4-diaminotoluene), 2,6-tolylenediamine (2,6-diaminotoluene), 4,4'-diphenylmethanediamine 2,4′-diphenylmethanediamine, 2,2′-diphenylmethanediamine, 4,4′-diphenyletherdiamine, 2-nitrodiphenyl-4,4′-diamine, 2,2′-diphenylpropane-4,4′- Diamine, 3,3′-dimethyldiphenylmethane-4,4′-diamine, 4,4′-diphenylpropanediamine, m-phenylenediamine, p-phenylenediamine, naphthylene-1,4-diamine, naphthylene-1,5- Examples include diamines and aromatic primary diamines such as 3,3′-dimethoxydiphenyl-4,4′-diamine.

  Examples of such araliphatic amines include araliphatic primary monoamines such as benzylamine, such as 1,3-bis (aminomethyl) benzene, 1,4-bis (aminomethyl) benzene, 1,3. -Tetramethylxylylenediamine (1,3-di (2-amino-2-methylethyl) benzene), 1,4-tetramethylxylylenediamine (1,4-bis (2-amino-2-methylethyl) And aromatic aliphatic primary diamines such as benzene).

In the above formula (5), examples of the functional group that may be substituted for R ⁸ include a nitro group, a hydroxyl group, a mercapto group, an oxo group, a thioxo group, a cyano group, a carboxy group, and an alkoxy-carbonyl group (for example, Methoxycarbonyl group, alkoxycarbonyl group having 2 to 4 total carbon atoms such as ethoxycarbonyl group), sulfo group, halogen atom (for example, fluorine, chlorine, bromine, iodine, etc.), lower alkoxy group (for example, methoxy group, ethoxy group) , Propoxy group, butoxy group, iso-butoxy group, sec-butoxy group, tert-butoxy group, etc.), aryloxy group (for example, phenoxy group), halogenophenoxy group (for example, o-, m-, or p-chloro) Phenoxy group, o-, m- or p-bromophenoxy group), lower alkylthio group (eg For example, a methylthio group, an ethylthio group, an n-propylthio group, an iso-propylthio group, an n-butylthio group, a tert-butylthio group, etc., an arylthio group (eg, a phenylthio group), a lower alkylsulfinyl group (eg, a methylsulfinyl group) , Ethylsulfinyl group etc.), lower alkylsulfonyl group (eg methylsulfonyl group, ethylsulfonyl group etc.), arylsulfonyl group (eg phenylsulfonyl etc.), lower acyl group (eg formyl group, acetyl group etc.), aryl Examples thereof include a carbonyl group (for example, a benzoyl group).

In the above formula (5), these functional groups may be substituted in plural for R ^8, and when the functional group is substituted in plural for R ⁸ , the functional groups may be the same as each other. , Each may be different.

  In the above formula (5), n represents, for example, an integer of 1 to 6, preferably 1 or 2, and more preferably 2.

  These amines can be used alone or in combination of two or more.

As the amine, preferably, in the above formula (5), R ⁸ is a primary amine which is an alicyclic hydrocarbon group having 3 to 15 carbon atoms, and R ⁸ is an aromatic ring-containing hydrocarbon having 6 to 15 carbon atoms. Primary amines that are groups, and more specifically, alicyclic amines having 3 to 15 carbon atoms, aromatic amines having 6 to 15 carbon atoms, and araliphatic amines having 6 to 15 carbon atoms. Is mentioned.

  Moreover, what becomes a manufacturing raw material of the isocyanate (after-mentioned) used industrially as an amine is also preferable, As such a primary amine, 1, 5- diamino pentane, 1, 6- diamino hexane, isophorone diamine, 1,3-bis (aminomethyl) cyclohexane, 1,4-bis (aminomethyl) cyclohexane, 4,4′-methylenebis (cyclohexylamine), 2,5-bis (aminomethyl) bicyclo [2,2 , 1] heptane, 2,6-bis (aminomethyl) bicyclo [2,2,1] heptane, 2,4-tolylenediamine (2,4-diaminotoluene), 2,6-tolylenediamine (2, 6-diaminotoluene), 4,4'-diphenylmethanediamine, 2,4'-diphenylmethanediamine, 2,2'-diphenylmethanedia , Naphthylene-1,5-diamine, 1,3-bis (aminomethyl) benzene, 1,4-bis (aminomethyl) benzene, 1,3-tetramethylxylylenediamine, 1,4-tetramethylxylylenediamine And particularly preferably, isophorone diamine, 2,4-tolylenediamine (2,4-diaminotoluene), 2,6-tolylenediamine (2,6-diaminotoluene), 4,4′-. Diphenylmethanediamine, 2,4′-diphenylmethanediamine, 2,2′-diphenylmethanediamine, naphthylene-1,5-diamine, 1,3-bis (aminomethyl) benzene, 1,4-bis (aminomethyl) benzene, 1 , 3-tetramethylxylylenediamine, 1,4-tetramethylxylylenediamine.

  N-unsubstituted carbamic acid ester is a carbamic acid ester in which the nitrogen atom in the carbamoyl group is not substituted by a functional group (that is, the nitrogen atom is bonded to two hydrogen atoms and one carbon atom). For example, it is represented by the following general formula (6).

_{^{R 7 O-CO-NH 2}} (6)
(In the formula, R ⁷ has the same meaning as R ^{7 in the} formula (4)).
In the above formula (6), ^{R 7} is as defined and ^{R 7} in the formula (4), i.e., ^{R 1} or ^{R 2, R 3} or ^{R 4} in the formula (2) of the above formula (1), the R ⁵ or R ⁶ in Formula (3) is shown, and more specifically, the above-described alkyl group (the alkyl group in Formula (1) or Formula (3) above) or the substituent described above. The aryl group which may have (the aryl group which may have the substituent in the said Formula (2) and the said Formula (3)) is shown.

Examples of the N-unsubstituted carbamic acid ester in which R ⁷ is the above-described alkyl group in the above formula (6) include, for example, methyl carbamate, ethyl carbamate, n-propyl carbamate, iso-propyl carbamate, carbamic acid. n-butyl, iso-butyl carbamate, sec-butyl carbamate, tert-butyl carbamate, pentyl carbamate, hexyl carbamate, heptyl carbamate, octyl carbamate, iso-octyl carbamate, 2-ethylhexyl carbamate, etc. Saturated hydrocarbon N-unsubstituted carbamic acid esters such as alicyclic saturated hydrocarbon N-unsubstituted carbamic acid esters such as cyclohexyl carbamate and cyclododecyl carbamate.

In the above formula (6), examples of N-unsubstituted carbamic acid ester in which R ⁷ is an aryl group which may have the above-described substituent include phenyl carbamate, tolyl carbamate, and xylyl carbamate. And aromatic hydrocarbon N-unsubstituted carbamic acid esters such as biphenyl carbamate, naphthyl carbamate, anthryl carbamate, phenanthryl carbamate, and the like.

  These N-unsubstituted carbamic acid esters can be used alone or in combination of two or more.

The N-unsubstituted carbamic acid ester is preferably an N-unsubstituted carbamic acid ester in which R ⁷ is an alkyl group in the above formula (6).

  The N-unsubstituted carbamic acid ester used as a raw material component for the carbamate reaction will be described in detail later, but preferably a low-boiling component (described later) separated after the carbamate reaction (N-unsubstituted carbamic acid ester). And N-unsubstituted carbamic acid ester obtained by further separation from (including carbonate).

  The alcohol is, for example, a primary to tertiary monohydric alcohol, and is represented by, for example, the following formula (7).

R ⁷ -OH ⁽⁷⁾
(In the formula, R ⁷ has the same meaning as R ^{7 in the} formula (4)).
In the above formula (7), ^{R 7} is as defined and ^{R 7} in the formula (4), i.e., ^{R 1} or ^{R 2, R 3} or ^{R 4} in the formula (2) of the above formula (1), the R ⁵ or R ⁶ in Formula (3) is shown, and more specifically, the above-described alkyl group (the alkyl group in Formula (1) or Formula (3) above) or the substituent described above. The aryl group which may have (the aryl group which may have the substituent in the said Formula (2) and the said Formula (3)) is shown.

In the above formula (7), examples of the alcohol in which R ⁷ is the above alkyl group include methanol, ethanol, n-propanol, iso-propanol, n-butanol (1-butanol), iso-butanol, sec-butanol. Linear or branched saturated hydrocarbon alcohols such as tert-butanol, pentanol, hexanol, heptanol, octanol, iso-octanol, 2-ethylhexanol, for example, alicyclic such as cyclohexanol, cyclododecanol, etc. Examples include saturated hydrocarbon alcohols.

In the formula (7), examples of the alcohol in which R ⁷ is an aryl group which may have the above-described substituent include, for example, phenol, hydroxytoluene, hydroxyxylene, biphenyl alcohol, naphthalenol, anthracenol, Examples include phenanthrenol.

  These alcohols can be used alone or in combination of two or more.

As the alcohol, preferably, in the above formula (7), it includes alcohol R ⁷ is an alkyl group, more preferably, R ⁷ can be mentioned alcohol is an alkyl group having 1 to 8 carbon atoms, more preferably , R ⁷ is an alkyl group having 2 to 6 carbon atoms.

  The alcohol used as a raw material component for the carbamate reaction is preferably an alcohol obtained by decomposing carbonate (the above formula (4)), and more specifically, although it will be described in detail later, it is separated after the carbamate reaction. Examples include alcohols (described later) obtained by further separating carbonates from decomposed low boiling point components (described later) (including N-unsubstituted carbamic acid esters and carbonates) to obtain carbonates.

  The carbonate is obtained as a by-product of the carbamation reaction by blending the above amine, urea and / or N-unsubstituted carbamic acid ester, and alcohol, and preferably reacting in the liquid phase. be able to.

  The mixing ratio of the amine, urea and / or N-unsubstituted carbamic acid ester, and alcohol is not particularly limited and can be appropriately selected within a relatively wide range.

  Usually, the compounding amount of urea and N-unsubstituted carbamic acid ester and the compounding amount of alcohol should be equimolar or more with respect to the amino group of the amine. Therefore, urea and / or the above-mentioned N-unsubstituted Carbamates and alcohols themselves can also be used as reaction solvents in this reaction.

  When urea and / or the above-mentioned N-unsubstituted carbamic acid ester or alcohol is also used as a reaction solvent, an excessive amount of urea and / or the above-mentioned N-unsubstituted carbamic acid ester or alcohol is used as necessary. However, if the excess amount is large, the energy consumption in the separation step after the reaction increases, which is not suitable for industrial production.

  Therefore, the blending amount of urea and / or the above-mentioned N-unsubstituted carbamic acid ester is 0.5 to 20 times mole, preferably 1 to 20 moles, based on one amino group of amine, from the viewpoint of improving the yield of carbamate. 1-10 times mole, More preferably, it is about 1-5 times mole, and the compounding quantity of alcohol is 0.5-100 times mole with respect to one amino group of an amine, Preferably, 1-20 The mole is more preferably about 1 to 10 moles.

  In this reaction, a reaction solvent is not necessarily required. For example, when the reaction raw material is solid or a reaction product is precipitated, for example, aliphatic hydrocarbons, aromatic hydrocarbons, ethers , Nitriles, aliphatic halogenated hydrocarbons, amides, nitro compounds, N-methylpyrrolidinone, N, N-dimethylimidazolidinone, dimethyl sulfoxide, and other reaction solvents to improve operability Can be made.

  Further, the amount of the reaction solvent is not particularly limited as long as the target product carbamate is dissolved, but industrially, it is necessary to recover the reaction solvent from the reaction solution. If the energy consumed for the recovery is reduced as much as possible and the blending amount is large, the reaction substrate concentration decreases and the reaction rate becomes slow. More specifically, it is used in the range of usually 0 to 500 parts by mass, preferably 0 to 100 parts by mass with respect to 1 part by mass of the amine.

  In this reaction, the reaction temperature is appropriately selected, for example, in the range of 100 to 350 ° C, preferably 150 to 300 ° C. When the reaction temperature is lower than this, the reaction rate may decrease. On the other hand, when the reaction temperature is higher than this, the side reaction may increase and the yield of the target product carbamate may decrease.

  The reaction pressure is usually atmospheric pressure, but may be increased when the boiling point of the component in the reaction solution is lower than the reaction temperature, and further reduced as necessary.

  Moreover, reaction time is 0.1 to 20 hours, for example, Preferably, it is 0.5 to 10 hours. If the reaction time is shorter than this, the yield of the target product carbamate may decrease. On the other hand, if it is longer than this, it is unsuitable for industrial production.

  In this method, a catalyst can also be used.

  Although it does not restrict | limit especially as a catalyst, For example, lithium methanolate, lithium ethanolate, lithium propanolate, lithium butanolate, sodium methanolate, potassium tert-butanolate, magnesium methanolate, calcium methanolate, tin chloride ( II), tin chloride (IV), lead acetate, lead phosphate, antimony chloride (III), antimony chloride (V), aluminum acetylacetonate, aluminum-isobutyrate, aluminum trichloride, bismuth chloride (III), copper acetate ( II), copper sulfate (II), copper nitrate (II), bis- (triphenyl-phosphine oxide) -copper chloride (II), copper molybdate, silver acetate, gold acetate, zinc oxide, zinc chloride, zinc acetate, Zinc acetonyl acetate, zinc octoate, Zinc oxide, zinc hexylate, zinc benzoate, zinc undecylate, cerium (IV) oxide, uranyl acetate, titanium tetraisopropanolate, titanium tetrabutanolate, titanium tetrachloride, titanium tetraphenolate, titanium naphthenate, chloride Vanadium (III), vanadium acetylacetonate, chromium chloride (III), molybdenum oxide (VI), molybdenum acetylacetonate, tungsten oxide (VI), manganese chloride (II), manganese acetate (II), manganese acetate (III) , Iron (II) acetate, iron (III) acetate, iron phosphate, iron oxalate, iron (III) chloride, iron (III) bromide, cobalt acetate, cobalt chloride, cobalt sulfate, cobalt naphthenate, nickel chloride, Examples thereof include nickel acetate and nickel naphthenate.

Furthermore, as a catalyst, for example, Zn (OSO ₂ CF ₃ ) ₂ (another notation: Zn (OTf) ₂ , zinc trifluoromethanesulfonate), Zn (OSO ₂ C ₂ F ₅ ) ₂ , Zn (OSO ₂ C ₃ F ₇ ) ₂ , Zn (OSO ₂ C ₄ F ₉ ) ₂ , Zn (OSO ₂ C ₆ H ₄ CH ₃ ) ₂ (p-toluenesulfonic acid zinc), Zn (OSO ₂ C ₆ H ₅ ) ₂ , Zn ( BF ₄ ) ₂ , Zn (PF ₆ ) ₂ , Hf (OTf) ₄ (hafnium trifluoromethanesulfonate), Sn (OTf) ₂ , Al (OTf) ₃ , Cu (OTf) _{2 and the} like are also included.

  These catalysts can be used alone or in combination of two or more.

  Moreover, the compounding quantity of a catalyst is 0.000001-0.1 mol with respect to 1 mol of amines, Preferably, it is 0.00005-0.05 mol. Even if the amount of the catalyst is larger than this, no further significant reaction promoting effect is observed, but the cost may increase due to an increase in the amount of the catalyst. On the other hand, if the blending amount is less than this, the reaction promoting effect may not be obtained.

  In addition, the addition method of a catalyst does not affect reaction activity in any addition method of lump addition, continuous addition, and a plurality of intermittent additions, and is not particularly limited.

  In this reaction, for example, amine, urea and / or N-unsubstituted carbamic acid ester, alcohol, and, if necessary, a catalyst and a reaction solvent are charged into the reaction vessel and stirred or mixed. Good. Then, for example, a carbamate represented by the following general formula (8) is generated as the main product.

^{(R 7 OCONH) n-R} 8 (8)
(Wherein, ^{R 8} is of the same meaning as ^{R 8} in the formula (5), ^{R 7} is the formula of the same meaning as ^{R 7} in (4), n is the same as n in the formula (5) Shows significance.)
In this reaction, ammonia is by-produced.

  In this reaction, when N-unsubstituted carbamic acid ester is blended, for example, an alcohol represented by the following general formula (9) is by-produced.

R ⁷ -OH (9)
(In the formula, R ⁷ has the same meaning as R ^{7 in the} formula (4)).
In this reaction, for example, an N-unsubstituted carbamic acid ester represented by the following general formula (10) is by-produced.

_{^{R 7 O-CO-NH 2}} (10)
(In the formula, R ⁷ has the same meaning as R ^{7 in the} formula (4)).
Furthermore, in this reaction, a carbonate represented by the following general formula (11) is by-produced.

R ⁷ O—CO—OR ⁷ (11)
(In the formula, two R ^{7 s} are the same as or different from each other and have the same meaning as R ^{7 in} formula (4) above)
In the formula (11), two R ^{7 s} are the same as or different from each other, and have the same meaning as R ^{7 in the} formula (4), that is, R ¹ or R ^{2 in} the formula (1), the formula (2) R ³ or R ^{4 in} the above formula (3), R ⁵ or R ^{6 in} the above formula (3), and more specifically, the same or different from each other, and the above alkyl groups (the above formula (1), the above An alkyl group in the formula (3)) or an aryl group which may have the above-described substituent (an aryl group which may have a substituent in the above formula (2) or the above formula (3)). Show.

In the above formula (11), when both R ⁷ are alkyl groups, the carbonate represented by the above formula (11) becomes the dialkyl carbonate represented by the above formula (1).

When R ⁷ is an aryl group which may have any substituent, the carbonate represented by the above formula (11) becomes a diaryl carbonate represented by the above formula (2).

Furthermore, when one R ⁷ is an alkyl group and the other R ⁷ is an aryl group which may have a substituent, the carbonate represented by the above formula (11) is represented by the above formula (3). ) Is an alkyl aryl carbonate.

  In this reaction, either a batch type or a continuous type can be adopted as the reaction type.

  Further, the carbamate (the above formula (8)) is separated from the obtained reaction solution by a known method, and for example, excess (unreacted) urea and / or N-unsubstituted carbamic acid ester, excess (unreacted). ) Alcohol, by-product alcohol (the above formula (9)), N-unsubstituted carbamic acid ester (the above formula (10)), carbonate (the above formula (11)), etc. As separate.

  Then, the carbamate (the above formula (8)) obtained in such a carbamate reaction is used, for example, for the production of isocyanate.

That is, an isocyanate represented by the following general formula (12) corresponding to the above amine by thermally decomposing the carbamate (the above formula (8)) obtained by the above carbamate reaction, and
^{R 8 - (NCO) n (} 12)
(Wherein, ^{R 8} is of the same meaning as ^{R 8} in the formula (5), n represents the same meaning as n in formula (5).)
An alcohol represented by the following general formula (13), which is a by-product, is generated.

R ⁷ -OH (13)
(In the formula, R ⁷ has the same meaning as R ^{7 in the} formula (4)).
This thermal decomposition is not particularly limited, and for example, a known decomposition method such as a liquid phase method or a gas phase method can be used.

  The alcohol obtained by thermal decomposition (the above formula (13)) is preferably used as a raw material component for carbamate reaction after being separated and recovered.

  As described above, alcohol (excess (unreacted) alcohol and by-product alcohol (the above formula (9)) are further separated from the low boiling point component (light boiling component) separated from the reaction solution obtained by the carbamate reaction. ))), N-unsubstituted carbamic acid ester and carbonate are roughly separated by distillation or the like, respectively, alcohol, N-unsubstituted carbamic acid ester and carbonate can be roughly separated and recovered, respectively.

  In this method, alcohol (excess (unreacted alcohol) and by-product alcohol) roughly separated from low-boiling components (light boiling components) is used as a raw material component for carbamate reaction.

  Thereby, the alcohol roughly separated from the low-boiling components (light boiling components) can be used industrially effectively.

  Further, N-unsubstituted carbamic acid ester roughly separated from the low boiling point component (light boiling point component) is used as a raw material component for carbamate reaction.

  Thereby, the N-unsubstituted carbamic acid ester roughly separated from the low boiling point component (light boiling component) can be industrially effectively used.

  In this method, the carbonate roughly separated from the low-boiling component (light boiling component) is contacted with high-pressure high-temperature water and decomposed into alcohol as described above.

  In this case, as described above, when the carbonate is a carbonate (formula (11)) obtained as a by-product by the reaction of an amine, urea and / or N-unsubstituted carbamic acid ester, and alcohol. Produces the alcohol represented by the following general formula (14) as the corresponding alcohol.

R ⁷ -OH (14)
(In the formula, R ⁷ has the same meaning as R ^{7 in the} formula (4)).
That is, by the decomposition of the carbonate roughly separated from the low-boiling component (light boiling component), an alcohol similar to the alcohol represented by the above formula (7), which is a raw material component of the carbamate reaction, is generated.

  In the rough separation of low-boiling components (light boiling components), N-unsubstituted carbamic acid ester may be contained in the carbonate. Even in such a case, the carbonate and the N-unsubstituted carbamic acid ester can be decomposed into alcohol at a time by contacting with high pressure and high temperature water.

  In this method, an alcohol obtained by decomposing carbonate (the above formula (14) is preferably used as a raw material component of the carbamate reaction described above.

  By using the alcohol obtained by decomposing the carbonate roughly separated from the low boiling point component as a raw material component for the carbamate reaction, the carbonate produced as a by-product in the carbamate reaction can be used industrially effectively.

  Thus, according to the method for treating carbonate of the present invention, since carbonate can be decomposed into alcohol, carbonate can be industrially effectively used.

  FIG. 1 is a schematic configuration diagram showing an embodiment of a plant in which the carbonate treatment method of the present invention is employed.

  Hereinafter, an embodiment of a plant in which the above-described carbonate processing method is industrially implemented will be described with reference to FIG. 1.

  In FIG. 1, this plant 1 is an isocyanate production apparatus in which the above-described carbonate processing method is adopted, and includes a reaction apparatus 2, a light boiling distillation apparatus 3, a thermal decomposition apparatus 4, a distillation apparatus 6, The hydrolyzing device 5 is provided.

  The reactor 2 is equipped in the plant 1 to produce carbamate by reaction of an amine, urea and / or N-unsubstituted carbamic acid ester, and alcohol.

  The reaction apparatus 2 includes a reaction tank 7, an amine supply pipe 8 connected to the reaction tank 7, a urea supply pipe 9, a carbamic acid ester supply pipe 11, and an alcohol supply pipe 10.

  The reaction vessel 7 is a carbamation reaction vessel for producing a carbamate by reacting an amine, urea and / or N-unsubstituted carbamic acid ester, and an alcohol, and is capable of controlling temperature and pressure. Consists of heat and pressure resistant container.

  Although not shown in such a reaction tank 7, for example, a catalyst supply pipe for supplying a catalyst to the reaction tank 7, and for replacing the inside of the reaction tank 7 with an inert gas (for example, nitrogen gas, etc.) if necessary. An inert gas supply pipe, a stirring device for stirring the inside of the reaction tank 7, an ammonia discharge pipe for distilling by-produced ammonia out of the system, and the like are provided.

  The amine supply pipe 8 is an amine supply line for supplying amine to the reaction tank 7, and its downstream end is connected to the reaction tank 7. Moreover, although not shown in figure, the upstream edge part is connected to the amine introduction line in which an amine is introduce | transduced.

  The urea supply pipe 9 is a urea supply line for supplying urea to the reaction tank 7, and its downstream end is connected to the reaction tank 7. Further, the upstream end thereof is connected to a urea introduction line through which urea is introduced, although not shown.

  The carbamic acid ester supply pipe 11 is an N-unsubstituted carbamic acid ester supply line for supplying N-unsubstituted carbamic acid ester to the reaction tank 7, and its downstream end is connected to the reaction tank 7. Yes. Further, the upstream end thereof is connected to an N-unsubstituted carbamic acid ester introduction line to which N-unsubstituted carbamic acid ester is introduced, though not shown.

  The carbamic acid ester supply pipe 11 is connected to the downstream end of a carbamic acid ester reflux pipe 28 (described later) in the middle of the flow direction.

  The alcohol supply pipe 10 is an alcohol supply line for supplying alcohol to the reaction tank 7, and its downstream end is connected to the reaction tank 7. Moreover, although not shown in figure, the upstream edge part is connected to the alcohol introduction line into which alcohol is introduced.

  In such an alcohol supply pipe 10, in the middle of the flow direction, a downstream end of an alcohol first reflux pipe 18 (described later), a downstream end of an alcohol second reflux pipe 25, and an alcohol third reflux pipe are provided. 29 (described later) downstream ends are connected.

  In the plant 1, the light boiling distillation apparatus 3 is configured to remove excess (unreacted) alcohol, urea and / or N-unsubstituted carbamic acid ester, alcohol as a by-product, from a reaction liquid obtained in the reaction tank 7. It is equipped to separate low-boiling components (light boiling components) such as N-unsubstituted carbamic acid esters and carbonates.

  The light boiling distillation apparatus 3 includes a light boiling distillation tank 13 and a first reaction liquid transport pipe 12 connected to the light boiling distillation tank 13.

  The light boiling distillation tank 13 is a distillation tank for distilling off the low-boiling components from the reaction solution obtained in the reaction apparatus 2 and is composed of a heat-resistant pressure-resistant vessel capable of controlling temperature and pressure.

  The first reaction liquid transport pipe 12 is a first reaction liquid transport line for transporting the reaction liquid produced in the reaction apparatus 2 to the light boiling distillation tank 13, and its downstream end is light boiling. It is connected to the distillation tank 13. Further, the upstream end thereof is connected to the reaction tank 7 in the reaction apparatus 2.

  The thermal decomposition apparatus 4 is installed in the plant 1 in order to decompose the reaction liquid into isocyanate and alcohol.

  This thermal decomposition apparatus 4 includes a thermal decomposition tank 16, a second reaction liquid transport pipe 15 connected to the thermal decomposition tank 16, an isocyanate discharge pipe 17, and an isocyanate residue discharge pipe 19.

  The thermal decomposition tank 16 is a decomposition tank that heats the reaction liquid obtained in the reaction apparatus 2 and decomposes it into isocyanate and alcohol, and includes a heat-resistant pressure-resistant container that can be controlled in temperature and pressure.

  Although not shown, such a pyrolysis tank 16 is provided with, for example, a solvent supply pipe for supplying a solvent to the pyrolysis tank 16 if necessary.

  The second reaction liquid transport pipe 15 is a second reaction liquid transport line for transporting the reaction liquid from which light boiling components have been distilled off in the light boiling distillation apparatus 3 to the thermal decomposition tank 16, on the downstream side thereof. An end portion is connected to the pyrolysis tank 16. Further, the upstream end thereof is connected to a light boiling distillation tank 13 in the light boiling distillation apparatus 3.

  The isocyanate discharge pipe 17 is an isocyanate discharge line for discharging isocyanate obtained by thermal decomposition of the reaction liquid from the plant 1, and its upstream end is connected to the thermal decomposition tank 16. Moreover, although the downstream edge part is not shown in figure, it is connected to the isocyanate purification line in which isocyanate is refine | purified.

  The isocyanate residue discharge pipe 19 is a residue discharge line for discharging the isocyanate residue (residue obtained by thermal decomposition of the reaction liquid) generated in the thermal decomposition apparatus 4, and its upstream end is connected to the thermal decomposition tank 16. It is connected. Moreover, although the downstream edge part is not shown in figure, it is connected to the isocyanate residue storage tank in which an isocyanate residue is stored.

  In the plant 1, the distillation apparatus 6 is for roughly separating alcohol, N-unsubstituted carbamic acid ester, and carbonate from the low boiling point component (light boiling point) obtained in the light boiling distillation tank 13. It is equipped.

  The distillation apparatus 6 includes a distillation column 26 and a light boiling component transport pipe 14 connected to the distillation column 26.

  The distillation column 26 roughly separates the N-unsubstituted carbamic acid ester from the low boiling point component (light boiling point) obtained in the light boiling distillation apparatus 3, roughly separates the carbonate, and further roughly separates the alcohol. And a known distillation column.

  The light boiling component transport pipe 14 is a light boiling component transport line for transporting the low boiling point component (light boiling component) obtained in the light boiling distillation device 3 to the distillation device 6, and its downstream end portion. Is connected to the distillation column 26. Further, the upstream end thereof is connected to a light boiling distillation tank 13 in the light boiling distillation apparatus 3.

  The hydrolysis apparatus 5 is installed in the plant 1 in order to decompose the carbonate roughly separated by the distillation apparatus 6 into alcohol with high-pressure high-temperature water.

  The hydrolysis apparatus 5 includes a hydrolysis tank 23, a carbonate transport pipe 27 and a water supply pipe 20 connected to the hydrolysis tank 23.

  The hydrolysis tank 23 is a hydrolysis tank for hydrolyzing carbonate into alcohol by bringing carbonate and high-pressure high-temperature water into contact with each other, and is composed of a heat-resistant pressure-resistant vessel capable of controlling temperature and pressure.

  Such a hydrolysis tank 23 is provided with a drain pipe 24 for discharging carbon dioxide by-produced by hydrolysis of carbonate, water used for hydrolysis, and the like from the plant 1.

  Moreover, although not shown in figure, such a hydrolysis tank 23 is equipped with the stirring apparatus etc. for stirring the inside of the hydrolysis tank 23 as needed, for example.

  The carbonate transport pipe 27 is a carbonate transport line for transporting the carbonate recovered in the distillation apparatus 6 to the hydrolysis apparatus 5, and its upstream end is connected to the distillation tower 26. Further, the downstream end thereof is connected to the hydrolysis tank 23 in the hydrolysis apparatus 5.

  In addition, a carbonate pressure pump (not shown) for pressure transporting carbonate toward the hydrolysis tank 23 is interposed in the middle of the carbonate transport pipe 27, if necessary. Further, if necessary, a carbonate pressure pump (FIG. A carbonate heater (not shown) for heating the carbonate is interposed downstream of the carbonate heater.

  The water supply pipe 20 is a water supply line for supplying high-pressure high-temperature water to the hydrolysis tank 23, is composed of a heat-resistant pressure-resistant pipe, and its downstream end is connected to the hydrolysis tank 23. Further, the upstream end is connected to a water supply line to which water (not shown) (process recovery water, ion exchange water, etc.) is supplied.

  Further, a water pressure pump 22 for pressure-transporting high-pressure high-temperature water toward the hydrolysis tank 23 is interposed in the middle of the water supply pipe 20. Further, in the middle of the water supply pipe 20, a water heater 21 for heating water is interposed downstream of the water pressure pump 22.

  Further, the plant 1 further includes an alcohol first reflux pipe 18, an alcohol second reflux pipe 25, an alcohol third reflux pipe 29, and a carbamate ester reflux pipe 28.

  The alcohol first reflux pipe 18 is an alcohol first reflux line for refluxing the alcohol obtained by thermally decomposing the reaction solution in the thermal decomposition apparatus 4 to the alcohol supply pipe 10 in the reaction apparatus 2. The upstream end is connected to the pyrolysis tank 16, and the downstream end is connected to the alcohol supply pipe 10 in the flow direction.

  The alcohol second reflux pipe 25 is an alcohol second reflux line for refluxing alcohol obtained by hydrolyzing carbonate in the hydrolysis apparatus 5 to the alcohol supply pipe 10 in the reaction apparatus 2, upstream of the alcohol second reflux pipe 25. The side end portion is connected to the hydrolysis tank 23, and the downstream end portion thereof is connected midway in the flow direction of the alcohol supply pipe 10.

  The alcohol third reflux pipe 29 is an alcohol third reflux line for refluxing the alcohol obtained by distilling a low-boiling component (light boiling component) in the distillation apparatus 6 to the alcohol supply pipe 10 in the reaction apparatus 2. The upstream end of the alcohol supply pipe 10 is connected to the distillation column 26 and the downstream end thereof is connected to the middle of the alcohol supply pipe 10 in the flow direction.

  The carbamic acid ester reflux pipe 28 refluxs the N-unsubstituted carbamic acid ester obtained by distilling the low-boiling component (light boiling point) in the distillation apparatus 6 to the carbamic acid ester supply pipe 11 in the reaction apparatus 2. The upstream end of the carbamic acid ester reflux line is connected to the distillation column 26, and the downstream end is connected to the middle of the carbamic acid ester supply pipe 11 in the flow direction.

  Next, this plant 1 produces carbamate and isocyanate, and roughly separates and decomposes the carbonate from the low-boiling components obtained in the production of carbamate, and the obtained alcohol is used again as a raw material component for carbamate reaction. The method used will be described.

  In this method, first, carbamate is produced in the reactor 2.

  In the production of this carbamate, the reaction apparatus 2 is continuously operated, and an amine, which is a carbamate raw material, urea and / or N-unsubstituted carbamic acid ester, and an alcohol, an amine supply pipe 8, and a urea supply pipe 9. And / or from the carbamic acid ester supply pipe 11 and the alcohol supply pipe 10, each of them is pressure-transported at the above-mentioned ratio and continuously supplied to the reaction tank 7. If necessary, a catalyst is supplied from a catalyst supply pipe (not shown) together with these raw material components.

  In this method, the amine, urea and / or N-unsubstituted carbamic acid ester, and alcohol are subjected to a carbamation reaction in the reaction tank 7, whereby the carbamate and by-product alcohol, N-unsubstituted A reaction liquid containing carbamic acid ester and carbonate is obtained.

  The reaction solution thus obtained is supplied to the first reaction solution transport pipe 12 and is pressure-transported to the light boiling distillation apparatus 3.

  Next, in this method, in the light boiling distillation apparatus 3 (light boiling distillation tank 13), for example, excess (unreacted) alcohol, urea and / or N-unsubstituted carbamic acid ester, by-product is produced from the reaction solution. The low-boiling components (light-boiling components) including alcohol, N-unsubstituted carbamic acid ester and carbonate are separated.

  The light boiling component separated in the light boiling distillation tank 13 is introduced into the light boiling component transport pipe 14 and supplied to the distillation apparatus 6.

  In this method, the low-boiling components (light boiling components) supplied to the distillation apparatus 6 are distilled in the distillation column 26, whereby N-unsubstituted carbamic acid ester, carbonate and alcohol (excess (unreacted)). Of alcohol and by-product alcohol).

  The roughly separated N-unsubstituted carbamic acid ester is introduced into the carbamic acid ester reflux pipe 28 and refluxed to the carbamic acid ester supply pipe 11. Thereby, the N-unsubstituted carbamic acid ester is supplied to the reaction tank 7.

  The roughly separated alcohol is introduced into the alcohol third reflux pipe 29 and refluxed to the alcohol supply pipe 10. Thereby, alcohol is supplied to the reaction tank 7.

  Then, the roughly separated carbonate (which may contain an N-unsubstituted carbamic acid ester) is supplied to the carbonate transport pipe 27 and pressure transported to the hydrolysis apparatus 5.

  Next, in this method, the carbonate is hydrolyzed in the hydrolysis apparatus 5.

  In the hydrolysis of carbonate, the hydrolysis apparatus 5 is continuously operated, and the carbonate supplied from the distillation apparatus 6 (distillation tower 26) through the carbonate transport pipe 27 is decomposed in the hydrolysis tank 23 under the above conditions. .

  That is, in this method, the carbonate is pressurized to a supply pressure of, for example, 3 to 30 MPa through the carbonate transport pipe 27 and heated to a supply temperature of, for example, 190 to 350 ° C. 23.

  On the other hand, the water flowing into the water supply pipe 20 from the water supply line is pressure-transported in the water supply pipe 20 toward the hydrolysis tank 23 by the water pressure pump 22 and heated by the water heater 21. . Thereby, the water is pressurized to 3 to 30 MPa and becomes high-pressure high-temperature water heated to 190 to 350 ° C. and flows into the hydrolysis tank 23.

  In the hydrolysis tank 23, for example, the tank temperature (decomposition temperature) is controlled to 190 to 350 ° C. and the tank pressure (decomposition pressure) is 3 to 30 MPa, and a carbonate pressure pump (not shown) and a water pressure pump are used. By the control of 22, the water addition ratio (mass ratio of high-pressure high-temperature water / carbonate) is controlled to, for example, 0.5 to 30.

  Thereby, in the hydrolysis tank 23, carbonate (which may contain N-unsubstituted carbamic acid ester) is continuously hydrolyzed by high-pressure high-temperature water, and a corresponding alcohol is produced as a decomposition product. Further, carbon dioxide produced as a by-product and water used in the hydrolysis are discharged from the plant 1 through the drain pipe 24.

  The produced alcohol is continuously separated, introduced into the alcohol second reflux pipe 25, and refluxed to the alcohol supply pipe 10. Thereby, alcohol is supplied to the reaction tank 7.

  On the other hand, in the light boiling distillation apparatus 3, the reaction liquid obtained as a residue after separating the light boiling component from the reaction liquid is supplied to the second reaction liquid transport pipe 15 and pressure transported to the thermal decomposition apparatus 4. The

  Next, in this method, the reaction solution is thermally decomposed in the thermal decomposition apparatus 4.

  In the thermal decomposition of the reaction liquid, the thermal decomposition apparatus 4 is continuously operated, and the reaction liquid supplied via the second reaction liquid transport pipe 15 is heated and pyrolyzed in the thermal decomposition tank 16 under the above conditions. .

  Thereby, isocyanate and alcohol are obtained as a decomposition liquid, and an isocyanate residue is obtained with isocyanate and alcohol.

  The isocyanate obtained in the pyrolysis tank 16 is discharged through an isocyanate discharge pipe 17 and transported to an isocyanate purification line (not shown).

  On the other hand, the alcohol obtained in the thermal decomposition tank 16 is separated from the decomposition solution, introduced into the alcohol first reflux pipe 18, and refluxed to the alcohol supply pipe 10. Thereby, alcohol is supplied to the reaction tank 7.

  The isocyanate residue obtained in the thermal decomposition tank 16 is transported to an isocyanate residue storage tank (not shown) via an isocyanate residue discharge pipe 19 and temporarily stored in the isocyanate residue storage tank (not shown). Then, for example, incineration processing, disposal processing, recycling processing, and the like are performed.

  And according to such a plant 1, while producing isocyanate continuously, roughly separating alcohol, N-unsubstituted carbamic acid ester, and carbonate obtained as a by-product, the alcohol and N-unsubstituted carbamine The acid ester and further the alcohol obtained by decomposing the carbonate can be refluxed for efficient use.

  As mentioned above, although the processing method of carbonate was demonstrated, such a plant 1 is a pretreatment apparatus for performing pretreatment processes, such as a dehydration process, an intermediate process, a distillation process, and a filtration process in an appropriate position if needed. Further, a post-processing apparatus for performing post-processing steps such as a purification step and a recovery step can be provided.

  EXAMPLES Next, although an Example is given and this invention is demonstrated in more detail, this invention is not limited to an Example at all.

The definitions of conversion and selectivity used in the examples are shown below.
<Conversion rate>
Conversion (%) = (mol number of carbonate consumed) ÷ (mol number of carbonate fed to the reactor−mol number of carbonate discharged from the pressure regulating valve during the reaction) × 100
<Selectivity>
Selectivity (mol%) = (mol number of alcohol produced / 2) ÷ (mol number of carbonate consumed) × 100
Preparation Example 1
(Carbamate reaction)
A mixture of 2,4-diaminotoluene and 2,6-diaminotoluene (mass ratio: 80/20) was added to a 1 L SUS autoclave equipped with a pressure control valve, a reflux condenser, a gas-liquid separator and a stirrer. (Hereinafter referred to as TDA) (80.6 g: 0.661 mol), urea (113 g: 1.88 mol) and 1-butanol (255 g: 3.44 mol) were charged, and further, zinc p-toluenesulfonate as a catalyst was used. (0.64 g: 1.57 mmol) and 1-butanol (23.4 g: 316 mmol) were charged, and the internal pressure was maintained so that the reaction temperature was maintained at 215 ° C. while stirring nitrogen gas at a flow rate of 1 L / min and 500 rpm. Was adjusted with a pressure control valve and reacted for 4 hours to obtain 410 g of a reaction solution.

When a part of the reaction solution was collected and quantified, 2,4-bis (butoxycarbonylamino) toluene was 38.9% by mass, 2,6-bis (butoxycarbonylamino) toluene was 9.48% by mass, -It was confirmed that butanol was 33.2% by mass, butyl carbamate was 13.2% by mass, and dibutyl carbonate was 2.83% by mass.
(Vacuum distillation under reduced pressure)
Into a 500 mL glass four-necked flask equipped with a stirrer and a condenser tube, 387.77 g of the reaction solution obtained by the carbamate reaction was charged, and the inside of the container was up to 2 kPa with a vacuum pump while stirring at 200 rpm. The pressure was reduced. With the circulating water at 25 ° C. flowing through the cooling pipe, the temperature in the container was raised to 100 ° C. to concentrate the reaction solution, and 125.44 g of light boiling components were distilled off.

  As a result of analyzing the distilled light boiling component by high performance liquid chromatography (HPLC) and gas chromatography (GC), it was confirmed that the main component was butanol. Subsequently, the circulating water temperature was set to 70 ° C., the temperature in the container was raised to 180 ° C., and the reaction solution was concentrated to obtain 195.89 g of a brown concentrate and 63.19 g of a light boiling point.

As a result of analyzing this light boiling component by HPLC and GC, it was confirmed that the main components were butyl carbamate and dibutyl carbonate.
(Separation of butyl carbamate and dibutyl carbonate)
63.19 g of a mixture of butyl carbamate and dibutyl carbonate (butyl carbamate: 90.9% by mass, dibutyl carbonate: 9.1% by mass) obtained by distilling off the light-boiling fraction under reduced pressure is equivalent to 20 theoretical plates. The distillate was fed to a distiller having a packing of 5 and was distilled under conditions of a pressure of 20 mmHg to obtain 6.36 g of dibutyl carbonate containing about 10% by mass of butyl carbamate.

Example 1
3.17 g of dibutyl carbonate containing about 10% of butyl carbamate obtained in Preparation Example 1 was charged into a 36 mL SUS autoclave equipped with a thermocouple and a pressure control valve, and the system was further charged with ion-exchanged water. Satisfied.

  The reactor was placed in an electric furnace and reacted for 20 minutes while adjusting with a pressure regulating valve so as to maintain a reaction temperature of 280 ° C and an internal pressure of 20 MPa. The water addition ratio (ion exchange water / dibutyl carbonate mass ratio) at this time was set to 11.

  After the reactor was allowed to cool to room temperature, the recovered reaction solution was analyzed by HPLC. As a result, it was confirmed that the conversion of dibutyl carbonate was 100% and the selectivity for n-butanol was 95.0 mol%. .

Example 2
3.04 g of dibutyl carbonate (DIALCARB M-2 manufactured by Mitsui Chemical Fine Co., Ltd.) was charged into a 36 mL SUS autoclave equipped with a thermocouple and a pressure control valve, and subjected to a decomposition reaction in the same manner as in Example 1.

  After allowing the reactor to cool to room temperature, a part of the reaction solution was collected and quantified by HPLC. As a result, the conversion of dibutyl carbonate was 100% and the selectivity for n-butanol was 92.9 mol%. Was confirmed.

Example 3
Dibutyl carbonate was decomposed by the same method as in Example 2 except that the reaction temperature was 200 ° C.

  After the reactor was allowed to cool to room temperature, the recovered reaction solution was analyzed by HPLC. As a result, it was confirmed that the conversion of dibutyl carbonate was 3.3% and the selectivity for n-butanol was 99 mol% or more. It was.

Example 4
In the same manner as in Example 2, 2.58 g of diphenyl carbonate was charged and decomposed.

  After allowing the reactor to cool to room temperature, a part of the recovered reaction solution was collected and quantified by GC. As a result, the conversion rate of diphenyl carbonate was 100%, and the selectivity of phenol was 99 mol% or more. confirmed.

DESCRIPTION OF SYMBOLS 1 Plant 2 Reaction apparatus 3 Light boiling distillation apparatus 4 Thermal decomposition apparatus 5 Hydrolysis apparatus 6 Distillation apparatus 7 Reaction tank 8 Amine supply pipe 9 Urea supply pipe 10 Alcohol supply pipe 11 Carbamate ester supply pipe 12 Reaction liquid transport pipe 13 Light Distillation tank 14 Light boiling component transport pipe 15 Reaction liquid transport pipe 16 Thermal decomposition tank 17 Isocyanate discharge pipe 18 Alcohol first reflux pipe 19 Isocyanate residue discharge pipe 20 Water supply pipe 21 Water heater 22 Water pressure pump 23 Hydrolysis tank 24 Drain pipe 25 Alcohol second reflux pipe 26 Distillation tower 27 Carbonate transport pipe 28 Carbamate ester reflux pipe 29 Alcohol third reflux pipe

Claims (4)

Dialkyl carbonate, at least one carbonate selected from the group consisting of diaryl carbonates and alkylaryl carbonates, 3～30MPa, and, in contact with the high pressure high temperature water of one hundred ninety to three hundred and fifty ° C., a method of decomposing the alcohol ,
The carbonate is further roughly separated from a low-boiling component containing an N-unsubstituted carbamic acid ester and carbonate separated after a carbamation reaction between an amine, urea and / or an N-unsubstituted carbamic acid ester, and an alcohol. A method for treating carbonate, characterized in that it is obtained by : The method for treating carbonate according to claim 1, wherein the carbonate contains an N-unsubstituted carbamic acid ester. The method for treating carbonate according to claim 1 or 2 , wherein the alcohol obtained by decomposing the carbonate is used as a raw material component of the carbamate reaction. The method for treating carbonate according to any one of claims 1 to 3, wherein the N-unsubstituted carbamic acid ester is roughly separated from the low boiling point component and used as a raw material component for the carbamate reaction.

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