CN108395374B - Process for producing diaryl carbonate - Google Patents
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- CN108395374B CN108395374B CN201710760626.6A CN201710760626A CN108395374B CN 108395374 B CN108395374 B CN 108395374B CN 201710760626 A CN201710760626 A CN 201710760626A CN 108395374 B CN108395374 B CN 108395374B
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Abstract
The invention provides a process for producing a diaryl carbonate, which can remove water which causes deterioration of a catalyst in a process for producing a diaryl carbonate without using a special apparatus. The method for producing a diaryl carbonate of the present invention is a method for producing a diaryl carbonate from an aromatic monohydroxy compound and a dialkyl carbonate comprising a compound represented by the following formula (1) in the presence of a catalyst, wherein the dialkyl carbonate contains the compound represented by the formula (1) in an amount of 0.01 to 1000 mass ppm relative to the dialkyl carbonate as a raw material (in the formula (1), R1, R2, and R4 each independently represent an aliphatic group having 1 to 20 carbon atoms, and R3 represents a hydrogen atom or an aliphatic group having 1 to 20 carbon atoms).
Description
Technical Field
The present invention relates to an industrial process for producing a diaryl carbonate. More specifically, the present invention relates to a method for efficiently removing water present in a diaryl carbonate production process.
Background
Diaryl carbonates are known to be produced by the reaction of dialkyl carbonates or phosgene with aromatic monohydroxy compounds.
There are various methods for producing dialkyl carbonate as a raw material. A typical dialkyl carbonate is dimethyl carbonate, and the following methods are exemplified as a method for producing dimethyl carbonate: a method for producing dimethyl carbonate from carbon dioxide, ethylene oxide and methanol (hereinafter referred to as "EO method"); a method for producing dimethyl carbonate from carbon dioxide, propylene oxide and methanol (hereinafter referred to as "PO method"); and a method for producing dimethyl carbonate from carbon monoxide, oxygen and methanol (hereinafter referred to as "CO method").
In addition, the following methods have been developed in recent years: a method for producing methyl nitrite from nitrogen monoxide, oxygen and methanol, and producing dimethyl carbonate by reacting the methyl nitrite with carbon monoxide (hereinafter referred to as "MN method"); a method for producing dimethyl carbonate from urea and methanol (hereinafter referred to as "direct urea method" and "indirect urea method").
A method for producing a diaryl carbonate by reacting a dialkyl carbonate with an aromatic monohydroxy compound is a typical production method of a diaryl carbonate. However, the presence of water in the diaryl carbonate production process has a problem of causing deterioration of the catalyst. The reason why water is present in the diaryl carbonate production step is that water is produced as a by-product during the production reaction of the aromatic monohydroxy compound, and this by-product water is contained in the aromatic monohydroxy compound as a raw material and is directly supplied to the diaryl carbonate production step.
It is known that water present in the diaryl carbonate production process deteriorates a catalyst used in the diaryl carbonate production process, and thus lowers the reaction efficiency, that is, lowers the amount of diaryl carbonate produced as a finished product. Therefore, a method for removing water present in the diaryl carbonate production process has been studied. For example, patent document 1 describes a method of removing water by distillation in the front stage of the reactor, and patent document 2 describes a method of removing water by using a stripping column containing a stripping agent.
Documents of the prior art
Patent document 1: japanese laid-open patent publication No. 2002-322130
Patent document 2: japanese Kohyo publication 2002-525346
Disclosure of Invention
Problems to be solved by the invention
However, although the methods of patent document 1 and patent document 2 can remove water present in the diaryl carbonate production process, both methods require special equipment.
The present invention has been made in view of the above circumstances, and an object thereof is to provide a method for easily removing water present in a diaryl carbonate production step without using a special apparatus such as a preceding distillative removal column or a stripping column.
Means for solving the problems
The present inventors have conducted extensive studies to solve the above problems and as a result, have found that water in a diaryl carbonate production process can be efficiently removed without using a special apparatus by allowing 0.01 to 1,000 mass ppm of a compound represented by the following general formula (1) to be present in a dialkyl carbonate as a raw material, thereby completing the present invention.
Namely, the present invention is as follows.
[1]
A process for producing a diaryl carbonate from an aromatic monohydroxy compound and a dialkyl carbonate containing a compound represented by the following formula (1) in the presence of a catalyst, wherein,
the dialkyl carbonate contains 0.01 to 1000 mass ppm of the compound represented by the formula (1) in the dialkyl carbonate as a raw material.
[ CHEM 1]
(in the formula (1), R1, R2 and R4 independently represent an aliphatic group having 1-20 carbon atoms, and R3 represents a hydrogen atom or an aliphatic group having 1-20 carbon atoms.)
[2]
The process for producing a diaryl carbonate according to [1], wherein the compound represented by the formula (1) is a dialkoxyalkane.
[3] The process for producing a diaryl carbonate according to [2], wherein the dialkoxyalkane is dimethoxypropane.
[4]
The process for producing a diaryl carbonate according to any one of [1] to [3], wherein the dialkyl carbonate is dimethyl carbonate.
ADVANTAGEOUS EFFECTS OF INVENTION
The present invention can effectively remove water that causes catalyst degradation in a diaryl carbonate production process, and can prevent a reduction in the amount of diaryl carbonate produced due to catalyst degradation.
Drawings
FIG. 1 is a flowchart showing an example of a production apparatus used in the method for producing a diaryl carbonate according to the present embodiment.
Description of the symbols
1: supply line for dialkyl carbonate to the 1 st continuous multi-stage distillation column 101
2: bottom component extraction line of the 1 st continuous multi-stage distillation column 101
3: bottom component extraction line of the 2 nd continuous multi-stage distillation column 102
4: overhead component extraction line of the 2 nd continuous multi-stage distillation column 102
5: overhead component extraction line of the 1 st continuous multi-stage distillation column 101
6: bottom component extraction line of the 3 rd continuous multi-stage distillation column 103
7: overhead component extraction line of the 3 rd continuous multi-stage distillation column 103
8: supply line of aromatic monohydroxy compound to 2 nd continuous multi-stage distillation column 102
9: liquid supply line to 2 nd continuous multi-stage distillation column 102
101: 1 st continuous multi-stage distillation column
102: 2 nd continuous multi-stage distillation column
103: 3 rd continuous multi-stage distillation column
Detailed Description
The mode for carrying out the invention of the present application (hereinafter referred to as "the present embodiment") will be described in further detail below, but the present invention is not limited thereto, and various modifications can be made without departing from the gist thereof.
The present embodiment provides a process for producing a diaryl carbonate from an aromatic monohydroxy compound and a dialkyl carbonate containing a compound represented by formula (1) in the presence of a catalyst, wherein,
the dialkyl carbonate contains 0.01 to 1000 mass ppm of the compound represented by the formula (1) in the dialkyl carbonate as a raw material.
[ CHEM 2]
(in the formula (1), R1, R2 and R4 independently represent an aliphatic group having 1-20 carbon atoms, and R3 represents hydrogen or an aliphatic group having 1-20 carbon atoms.)
Examples of the aliphatic group having 1 to 20 carbon atoms include an alkyl group, an alkenyl group, an alkynyl group, and an aryl group.
Examples of the alkyl group include chain alkyl groups such as a methyl group, an ethyl group, a propyl group (including isomers), a butyl group (including isomers), a pentyl group (including isomers), a hexyl group (including isomers), a heptyl group (including isomers), an octyl group (including isomers), a nonyl group (including isomers), a decyl group (including isomers), and a cyclohexylmethyl group; cyclic alkyl groups such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl and cycloheptyl; and so on.
Examples of the alkenyl group include a vinyl group, a propenyl group (including isomers), a butenyl group (including isomers), a pentenyl group (including isomers), a hexenyl group (including isomers), and the like.
Examples of the alkynyl group include an ethynyl group, a propynyl group (including each isomer), a butynyl group (including each isomer), a pentynyl group (including each isomer), a hexynyl group (including each isomer), and the like.
Examples of the aryl group include a phenyl group and a naphthyl group.
The compound represented by the formula (1) may be used alone, or 2 or more compounds may be used in combination.
Among the aliphatic groups having 1 to 20 carbon atoms, preferred are chain alkyl groups, alkenyl groups and alkynyl groups having 1 to 6 carbon atoms, and more preferred are chain alkyl groups having 1 to 3 carbon atoms.
Examples of the compound represented by the formula (1) include, for example, 2-dimethoxypropane in which all of R1, R2, R3 and R4 are aliphatic groups having 1 carbon atom; and dialkoxyalkanes such as 1, 1-dimethoxypropane in which R1 and R4 are aliphatic groups having 1 carbon atom, R2 is an aliphatic group having 2 carbon atoms, and R3 is hydrogen. Among dialkoxyalkanes, dimethoxypropane is preferred.
[ CHEM 3]
2, 2-dimethoxypropane
[ CHEM 4 ]
1, 1-dimethoxypropane
In the dialkyl carbonate in the present embodiment, 2, 2-dimethoxypropane and 1, 1-dimethoxypropane are preferably contained in an amount of 0.01 to 1000 mass ppm in the dialkyl carbonate as a raw material. The mass ratio of 2, 2-dimethoxypropane to 1, 1-dimethoxypropane is not particularly limited, and is preferably 20: 1-1: 20. more preferably 10: 5-10: 1.
the mechanism of removing water present in the diaryl carbonate production step from the compound represented by the above formula (1) is considered as follows. In the following, 1-dimethoxypropane and 2, 2-dimethoxypropane are used as examples, but the present embodiment is not limited to these dialkoxyalkanes.
1, 1-dimethylpropane is reacted with water according to the following reaction scheme to give the hemiacetal.
[ CHEM 5 ]
2, 2-dimethylpropane reacts with water according to the following reaction formula to produce a hemiacetal.
[ CHEM 6 ]
The hemiacetal formed is then subjected to dealcoholation to form aldehydes and ketones according to the following reaction scheme.
[ CHEM 7 ]
The aldehydes and ketones generated by the above reaction are removed from a distillation column or the like provided in the diaryl carbonate production step for purifying the diaryl carbonate or the like. Therefore, the smaller the number of carbon atoms of R1, R2, R3 and R4 in the compound represented by the formula (1), the lower the boiling point of the reaction product of water and the compound represented by the formula (1), and therefore, the separation by a distillation column or the like is easy.
The compound represented by the above formula (1) may be added to dialkyl carbonate as a raw material of diaryl carbonate, or the compound represented by the above formula (1) by-produced by, for example, the following reaction may be left in dimethyl carbonate as a raw material in a step of producing dialkyl carbonate, thereby lowering the distillation separation efficiency and load.
[ CHEM 8 ]
The concentration of the compound represented by the formula (1) contained in the dialkyl carbonate is 0.01 to 1000 mass ppm, preferably 1 to 200 mass ppm. When the concentration of the compound represented by the above formula (1) is less than 0.01 ppm by weight, water remains in the diaryl carbonate production step, and the effects of the present invention may not be sufficiently obtained. When the concentration of the compound represented by the above formula (1) is higher than 1000 mass ppm, the compound represented by the above formula (1) may undergo a side reaction with the aromatic monohydroxy compound or the like, and the reaction product thereof may be mixed as an impurity into the diaryl carbonate to lower the purity of the diaryl carbonate, and may adversely affect the color tone or the like of the aromatic polycarbonate produced using the diaryl carbonate as a raw material.
The dialkyl carbonate as a raw material can be produced by any one of the following methods: a method for producing dimethyl carbonate from carbon dioxide, ethylene oxide and methanol (EO method); a method for producing dimethyl carbonate from carbon dioxide, propylene oxide and methanol (PO method); a method for producing dimethyl carbonate from carbon monoxide, oxygen and methanol (CO method); a method for producing methyl nitrite from nitrogen monoxide, oxygen and methanol, and producing dimethyl carbonate by reacting the methyl nitrite with carbon monoxide (MN method); a process for producing dimethyl carbonate from urea and methanol (direct urea process, indirect urea process), wherein the dialkyl carbonate is represented by the formula (2).
RaOCOORa (2)
Here, RaRepresents an alkyl group having 1 to 10 carbon atoms, an alicyclic group having 3 to 10 carbon atoms, or an aralkyl group having 6 to 10 carbon atoms. As such RaExamples thereof include alkyl groups such as methyl, ethyl, propyl (including isomers), allyl, butyl (including isomers), butenyl (including isomers), pentyl (including isomers), hexyl (including isomers), heptyl (including isomers), octyl (including isomers), nonyl (including isomers), decyl (including isomers), and cyclohexylmethyl; alicyclic groups such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl and cycloheptyl; aralkyl groups such as benzyl, phenethyl (including isomers), phenylpropyl (including isomers), phenylbutyl (including isomers), and methylbenzyl (including isomers). These alkyl groups, alicyclic groups, and aralkyl groups may be substituted with other substituents, for example, lower alkyl groups, lower alkoxy groups, cyano groups, halogens, and the like, and may have an unsaturated bond.
As having such RaExamples of the dialkyl carbonate of (a) include dimethyl carbonate, diethyl carbonate, dipropyl carbonate (including isomers), diallyl carbonate, dibutylene carbonate (including isomers), dibutyl carbonate (including isomers), dipentyl carbonate (including isomers), dihexyl carbonate (including isomers), diheptyl carbonate (including isomers), and dioctyl carbonate (including isomers)Isomers), dinonyl carbonate (including isomers), didecyl carbonate (including isomers), dicyclopentyl carbonate, dicyclohexyl carbonate, bicycloheptyl carbonate, dibenzyl carbonate, diphenylethyl carbonate (including isomers), dipropyl carbonate (including isomers), di (phenylbutyl) carbonate (including isomers), di (chlorobenzyl) carbonate (including isomers), di (methoxybenzyl) carbonate (including isomers), di (methoxymethyl) carbonate, di (methoxyethyl) carbonate (including isomers), di (chloroethyl) carbonate (including isomers), di (cyanoethyl) carbonate (including isomers), and the like.
Among them, R is preferable in the present embodimentaA dialkyl carbonate containing a halogen-free alkyl group having 4 or less carbon atoms, and more preferably dimethyl carbonate. Further, a dialkyl carbonate produced in a substantially halogen-free state is more preferable, and for example, a dialkyl carbonate produced from an alkylene carbonate substantially containing no halogen and an alcohol substantially containing no halogen is preferable.
The dialkyl carbonate may contain impurities such as ethers, esters, alcohols, carbonates, and alkanes. The impurities in the dialkyl carbonate are not particularly limited, and examples thereof include the following impurities.
0.01-50 mass ppm of dimethyl ether
0.01 to 50 mass ppm of 2-methoxypropene
0.01 ppm-50 ppm of 1, 1-dimethoxyethane
0.01-50,000 mass ppm of methanol
0.01 to 50 mass ppm of methyl propionate
0.01-50 ppm by mass of 3, 3-dimethoxy-1-propene
0.01-50 mass ppm of 1, 4-dioxane
0.01-500 ppm by mass of ethyl methyl carbonate
0.01 to 500 ppm by mass of bis (2-methoxyethyl) carbonate
0.01-50 mass ppm of toluene
0.01-50 ppm by mass of methyl 3-butyrate
0.01 to 50 mass ppm of 2-ethyl-4-methyl-1, 3-dioxole
0.01-50 ppm by mass of cycloheptatriene
0.01-50 ppm by mass of 1-methoxy-2-propanol
0.01 to 50 mass ppm of diethylene glycol diethyl ether
0.01 ppm-50 ppm dodecane
Tetradecane 0.01-50 ppm by mass
0.01 to 50 mass ppm of hexadecane
Octadecane 0.01-50 mass ppm
0.01-50 ppm by mass of eicosane
The aromatic monohydroxy compound as a raw material in the present embodiment is not particularly limited as long as it is a compound in which a hydroxyl group is directly bonded to an aromatic group, and examples thereof include a compound represented by the following formula (3).
Ar3OH(3)
(in formula (3), Ar3Represents an aromatic group having 5 to 30 carbon atoms. )
Examples of the compound represented by formula (3) include various alkylphenols such as phenol, cresol (including isomers), xylenol (including isomers), trimethylphenol (including isomers), tetramethylphenol (including isomers), ethylphenol (including isomers), propylphenol (including isomers), butylphenol (including isomers), diethylphenol (including isomers), methylethylphenol (including isomers), methylpropylphenol (including isomers), dipropylphenol (including isomers), methylbutylphenol (including isomers), pentylphenol (including isomers), hexylphenol (including isomers), and cyclohexylphenol (including isomers); various alkoxyphenols such as methoxyphenol (including various isomers) and ethoxyphenol (including various isomers); aralkyl phenols such as phenylpropyl phenol (including isomers); naphthols (including isomers) and various substituted naphthols; heteroaromatic monohydroxy compounds such as hydroxypyridine (including isomers), hydroxycoumarin (including isomers), and hydroxyquinoline (including isomers).
These aromatic monohydroxy compounds may be used in the form of 1 or a mixture thereof. Among these aromatic monohydroxy compounds, Ar is preferred in the present embodiment3Is an aromatic monohydroxy compound formed of an aromatic group having 6 to 10 carbon atoms, and is more preferably phenol. Among these aromatic monohydroxy compounds, in the present embodiment, an aromatic monohydroxy compound substantially free of halogen is preferable.
In addition, the aromatic monohydroxy compound usually contains water in the range of 0 to 500 mass ppm, but the effect of the present invention is not hindered.
The diaryl carbonate produced by the present embodiment is generally a compound represented by the following formula (4).
Ar4-OCOO-Ar5(4)
(wherein Ar is4、Ar5Each independently represents a 1-valent aromatic group. )
Ar4And Ar5Wherein the 1-valent aromatic group represents a 1-valent carbocyclic or heterocyclic aromatic group in the Ar4、Ar5In the method for producing a diaryl carbonate according to the present embodiment, 1 or more hydrogen atoms may be substituted with another substituent which does not affect the reaction in the method for producing a diaryl carbonate according to the present embodiment, for example, a halogen atom, an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, a phenyl group, a phenoxy group, a vinyl group, a cyano group, an ester group, an amide group, a nitro group, or the like. Ar (Ar)4、Ar5May be the same or different. As a 1-valent aromatic radical Ar4And Ar5As representative examples thereof, there may be mentioned phenyl, naphthyl, biphenyl and pyridyl. They may be substituted with 1 or more of the substituents described above. As preferred Ar4And Ar5Examples thereof include groups represented by the following formula (5).
[ CHEM 9 ]
A preferred diaryl carbonate is a substituted or unsubstituted diphenyl carbonate represented by the following formula (6).
[ CHEM 10 ]
(in the formula, R9And R10Each independently represents a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, a cycloalkyl group having 5 to 10 ring-forming carbon atoms or a phenyl group, p and q are integers of 1 to 5, and when p is 2 or more, each R9Each may be different, when q is 2 or more, each R10Each may be different. )
Among the diaryl carbonates, non-substituted diphenyl carbonate, or symmetrical diaryl carbonates such as lower alkyl-substituted diphenyl carbonate like dibenzyl carbonate and di-t-butylphenyl carbonate are preferable, and non-substituted diphenyl carbonate is more preferable. These diaryl carbonates may be used alone or in combination of 2 or more.
The amount ratio of the dialkyl carbonate to the aromatic monohydroxy compound used as the raw material in the present embodiment is preferably 0.1 to 10 in terms of a molar ratio. If the amount is outside the above range, the amount of the unreacted raw material remaining is increased relative to the predetermined amount of the target diaryl carbonate produced, and therefore, it is inefficient, and a large amount of energy is required for recovering the unreacted raw material. From this viewpoint, the molar ratio of the dialkyl carbonate to the aromatic monohydroxy compound is more preferably 0.5 to 5, still more preferably 0.8 to 3, and still more preferably 1 to 2.
Specifically, the method for producing a diaryl carbonate according to the present embodiment is preferably a method for producing a diaryl carbonate comprising the steps of: (i) feeding a dialkyl carbonate containing 0.01 to 1000 mass ppm of a compound represented by formula (1) into a 1 st continuous multi-stage distillation column, continuously distilling the dialkyl carbonate, withdrawing aldehydes and/or ketones generated by the reaction of the compound represented by formula (1) with water from the top of the column, and withdrawing a mixture containing the dialkyl carbonate and the compound represented by formula (1); (ii) (ii) continuously feeding the mixture obtained in the step (i) and the aromatic monohydroxy compound into a 2 nd continuous multi-stage distillation column in which a catalyst is present; (iii) a step of reacting the dialkyl carbonate and the aromatic monohydroxy compound in the 2 nd continuous multi-stage distillation column to produce an alcohol and an alkylaryl carbonate; (iv) continuously withdrawing the produced 2 nd low boiling point reaction mixture containing the alcohol from the upper part of the 2 nd continuous multi-stage distillation column and continuously withdrawing the produced 2 nd high boiling point reaction mixture containing the alkylaryl carbonates from the lower part of the 2 nd continuous multi-stage distillation column in a liquid state; (v) continuously feeding the 2 nd high boiling point reaction mixture into a 3 rd continuous multi-stage distillation column connected to the 2 nd continuous multi-stage distillation column in the presence of a catalyst, and reacting the mixture in the 3 rd continuous multi-stage distillation column to produce dialkyl carbonates and diaryl carbonates; and (vi) continuously withdrawing the produced 3 rd column low boiling point reaction mixture containing dialkyl carbonates from the upper part of the 3 rd continuous multi-stage distillation column, and continuously withdrawing the produced 3 rd column high boiling point reaction mixture containing diaryl carbonates from the lower part of the 3 rd continuous multi-stage distillation column in a liquid state.
In the above-mentioned method for producing a diaryl carbonate, it is preferable that the aldehydes and/or ketones produced by the reaction of the compound represented by the formula (1) with water be extracted from the top of the column in a gaseous state in the 1 st continuous multi-stage distillation column, the 2 nd continuous multi-stage distillation column, and the 3 rd continuous multi-stage distillation column.
The 2 nd low-boiling reaction mixture is preferably supplied to the 1 st continuous multi-stage distillation column, and the 3 rd column low-boiling reaction mixture is preferably supplied to the 2 nd continuous multi-stage distillation column. The 2 nd low boiling point reaction mixture and the 3 rd column low boiling point reaction mixture may contain, for example, 1 or more selected from the group consisting of alcohols, dialkyl carbonates, aromatic monohydroxy compounds, compounds represented by formula (1), water, and the like.
Examples of the catalyst used in the present embodiment include 1 or more selected from the group consisting of the following lead compounds, copper group metal compounds, alkali metal complexes, zinc complexes, cadmium complexes, iron group metal compounds, zirconium complexes, lewis acid compounds, organic tin compounds, and the like.
< lead Compound >
Examples of the lead compound include:
PbO、PbO2、Pb3O4lead oxides, etc.;
PbS、Pb2s and other lead sulfides;
Pb(OH)2、Pb2O2(OH)2lead hydroxides, etc.;
Na2PbO2、K2PbO2、NaHPbO2、KHPbO2and the like plumbites;
Na2PbO3、Na2H2PbO4、K2PbO3、K2[Pb(OH)6]、K4PbO4、Ca2PbO4、CaPbO3lead acid salts;
PbCO3、2PbCO3·Pb(OH)2carbonates of lead and their alkaline salts;
Pb(OCOCH3)2、Pb(OCOCH3)4、Pb(OCOCH3)2·PbO·3H2lead salts of organic acids such as O and carbonates or basic salts thereof;
Bu4Pb、Ph4Pb、Bu3PbCl、Ph3PbBr、Ph3pb (or Ph)6Pb2)、Bu3PbOH、Ph3Organolead compounds such as PbO (Bu represents a butyl group, and Ph represents a phenyl group);
Pb(OCH3)2、(CH3O)Pb(OPh)、Pb(OPh)2lead alkoxides and lead aryloxides;
lead alloys such as Pb-Na, Pb-Ca, Pb-Ba, Pb-Sn and Pb-Sb;
lead minerals such as galena and sphalerite, and hydrates of their lead compounds; and so on.
< Compounds of copper group metals >
Examples of the compound of a copper group metal include:
CuCl、CuCl2、CuBr、CuBr2、CuI、CuI2、Cu(OAc)2、Cu(acac)2copper oleate, Bu2Cu、(CH3O)2Cu、AgNO3AgBr, silver picrate, AgC6H6ClO4、[AuC≡C-C(CH3)3]n、[Cu(C7H8)Cl]4Salts and complexes of copper group metals (acac represents an acetylacetone chelating ligand); and so on.
< complexes of alkali metals >
Examples of the alkali metal complex include:
Li(acac)、LiN(C4H9)2alkali metal complexes; and so on.
< Complex of Zinc >
Examples of the zinc complex include:
Zn(acac)2zinc complexes; and so on.
< Complex of cadmium >
Examples of the cadmium complex include:
Cd(acac)2and cadmium complexes; and so on.
< Compound of iron group Metal >
Examples of the compound of an iron group metal include:
Fe(C10H8)(CO)5、Fe(CO)5、Fe(C4H6)(CO)3co (trimethylbenzene)2(PEt2Ph)2、CoC5F5(CO)7、Ni-π-C5H5Complexes of iron group metals such as NO and ferroceneA compound; and so on.
< zirconium Complex >
Examples of the zirconium complex include:
Zr(acac)4zirconium complexes such as zirconocene; and so on.
< Lewis acid-based Compound >
Examples of the lewis acid compound include:
AlX3、TiX3,TiX4、VOX3、VX5、ZnX2、FeX3、SnX4(where X is a halogen, acetoxy, alkoxy, aryloxy group) or the like Lewis acid and Lewis acid-generating transition metal compound; and so on.
< organotin compounds >
Examples of the organotin compound include:
(CH3)3SnOCOCH3、(C2H5)3SnOCOC6H5、Bu3SnOCOCH3、Ph3SnOCOCH3、Bu2Sn(OCOCH3)2、Bu2Sn(OCOC11H23)2、Ph3SnOCH3、(C2H5)3SnOPh、Bu2Sn(OCH3)2、Bu2Sn(OC2H5)2、Bu2Sn(OPh)2、Ph2Sn(OCH3)2、(C2H5)3SnOH、Ph3SnOH、Bu2SnO、(C8H17)2SnO、Bu2SnCl2organotin compounds such as BuSnO (OH); and so on.
The metal-containing compound described above is used as a catalyst. These catalysts may be solid catalysts fixed in the multistage distillation column or soluble catalysts dissolved in the reaction system.
These catalyst components may be reacted with organic compounds present in the reaction system, for example, aliphatic alcohols, aromatic monohydroxy compounds, alkyl aryl carbonates, diaryl carbonates, dialkyl carbonates, or the like, or may be subjected to heat treatment with raw materials or products before the reaction.
When the diaryl carbonate production step is carried out using a soluble catalyst dissolved in the reaction system, among these catalysts, a catalyst having high solubility in the reaction solution under the reaction conditions is preferable. Preferable catalysts include PbO and Pb (OH) from the viewpoint of solubility in the reaction solution2、Pb(OPh)2；TiCl4、Ti(OMe)4、(MeO)Ti(OPh)3、(MeO)2Ti(OPh)2、(MeO)3Ti(OPh)、Ti(OPh)4；SnCl4、Sn(OPh)4、Bu2SnO、Bu2Sn(OPh)2；FeCl3、Fe(OH)3、Fe(OPh)3And the like, or a treated product obtained by treating these catalysts with phenol, a reaction solution, or the like.
The catalyst used in the 2 nd continuous multi-stage distillation column and the catalyst used in the 3 rd continuous multi-stage distillation column may be the same type or different types, and the same type of catalyst is preferred. The catalyst is more preferably the same kind of catalyst that can be dissolved in both reaction solutions. When the catalyst is of the same kind and is soluble in both reaction liquids, the catalyst is usually extracted from the lower part of the 2 nd continuous multi-stage distillation column together with an alkyl aryl carbonate or the like in a state of being dissolved in the high boiling point reaction mixture in the 2 nd continuous multi-stage distillation column and directly supplied to the 3 rd continuous multi-stage distillation column, and therefore, this is a preferred embodiment. If necessary, the catalyst may be newly added to the 3 rd continuous multi-stage distillation column.
The 1 st, 2 nd and 3 rd continuous multi-stage distillation columns are preferably distillation columns having trays and/or packings as internals. The internal means are those portions of the distillation column which are actually in gas-liquid contact. As the tray, for example, a bubble-cap tray, a perforated tray, a valve tray, a counter-current tray, a superfrac tray, a max rectification tray (maxfrac tray), and the like are preferable. Examples of the fillers include irregular fillers such as Raschig rings, Lesinc rings, pall rings, saddle fillers, Intel rock saddles, Dieckel rings, Memagawa fillers, and Heli-park fillers; orifice plate corrugated packing (Mellapak), GemPak, Techno-Pak, Flexi-Pak, Sulzer packing, Goodroll packing, Glitchgrid, and the like. As the 1 st, 2 nd and 3 rd continuous multi-stage distillation columns, a multi-stage distillation column having a tray part and a part filled with a packing in combination may also be used.
In the following, the term "number of stages of internals" means the number of stages in the case of trays and the number of theoretical stages in the case of packings. Thus, in the case of combining a multistage distillation column having a tray section and a section filled with a packing, the number of stages of the internals is the sum of the number of trays and the theoretical number of stages.
The reaction time of the transesterification reaction in the diaryl carbonate production step may be equivalent to the average residence time of each reaction liquid in the 2 nd continuous multi-stage distillation column and the 3 rd continuous multi-stage distillation column, and may vary depending on the shape or number of stages of the internal parts of each distillation column, the amount of raw material supplied, the kind or amount of catalyst, the reaction conditions, and the like, and the reaction time in each of the 2 nd continuous multi-stage distillation column and the 3 rd continuous multi-stage distillation column is usually 0.01 to 10 hours, preferably 0.05 to 5 hours, and more preferably 0.1 to 3 hours.
The reaction temperature of the 2 nd continuous multi-stage distillation column can be adjusted by the kind of raw material used, the kind or amount of catalyst, and is usually in the range of 100 to 350 ℃. From the viewpoint of increasing the reaction rate, it is preferable to increase the reaction temperature, but a high reaction temperature is not preferable because side reactions are likely to occur, and by-products such as alkylaryl ethers increase. The reaction temperature in the 2 nd continuous multi-stage distillation column is preferably in the range of 130 to 280 ℃, more preferably 150 to 260 ℃, and still more preferably 180 to 250 ℃ from the viewpoint of enhancing the reaction rate and suppressing side reactions.
The reaction temperature of the 3 rd continuous multi-stage distillation column can be adjusted by the kind of raw material used, the kind or amount of catalyst, and is usually in the range of 100 to 350 ℃. From the viewpoint of increasing the reaction rate, it is preferable to increase the reaction temperature, but a high reaction temperature is not preferable because side reactions are likely to occur, and for example, by-products such as an alkyl aryl ether, a Fries rearrangement product of an alkyl aryl carbonate or diaryl carbonate as a raw material or a product, or a derivative thereof increase. The reaction temperature in the 3 rd continuous multi-stage distillation column is preferably in the range of 130 to 280 ℃, more preferably 150 to 260 ℃, and still more preferably 180 to 250 ℃ from the viewpoint of enhancing the reaction rate and suppressing side reactions.
The pressure of the 1 st continuous multi-stage distillation column can be adjusted by the kind or composition of the raw material compound used, the reaction temperature, etc., and may be any of reduced pressure, normal pressure and increased pressure, and usually the column top pressure is preferably 0.1Pa to 2X 10 Pa7Pa, more preferably 105Pa～107Pa, more preferably 2X 105Pa～5×106Pa range.
The temperature of the 1 st continuous multi-stage distillation column is not particularly limited as long as it is a temperature at which aldehydes and/or ketones generated by the reaction of the compound represented by the formula (1) and water can be distilled off.
The reaction pressure of the 2 nd continuous multi-stage distillation column can be adjusted by the kind or composition of the raw material compound used, the reaction temperature, and the like, and may be any of reduced pressure, normal pressure, and increased pressure, and usually, the column top pressure is preferably 0.1Pa to 2X 10 Pa7Pa, more preferably 105Pa～107Pa, more preferably 2X 105Pa～5×106Pa range.
The reaction pressure in the 3 rd continuous multi-stage distillation column can be adjusted by the kind and composition of the raw material compound used, the reaction temperature, and the like, and may be any of reduced pressure, normal pressure, and increased pressure, and usually, the column top pressure is preferably 0.1Pa to 2X 10 Pa7Pa, more preferably 103Pa～106Pa, more preferably 5X 103Pa～105Pa range.
As the 2 nd continuous multi-stage distillation column in the diaryl carbonate production step, 2 or more distillation columns may be used. In this case, 2 or more distillation columns may be connected in series, in parallel, or in a combination of series and parallel.
The material constituting the 1 st, 2 nd and 3 rd continuous multi-stage distillation columns used in the diaryl carbonate production step is mainly a metal material such as carbon steel or stainless steel, and stainless steel is preferred in view of the quality of the produced diaryl carbonate.
An aromatic polycarbonate may be produced using the aromatic dihydroxy compound and the diaryl carbonate produced in the present embodiment as raw materials. For example, the following methods can be mentioned: the aromatic polycarbonate is produced by using a horizontal polymerization vessel such as a guide contact flow type polymerization vessel for polymerizing a molten prepolymer while allowing the molten prepolymer to flow down along the surface of a guide, or a horizontal polymerization vessel having a rotation axis of a stirring paddle in a horizontal direction.
The following is a specific description of a method for producing an aromatic polycarbonate by polymerizing a molten prepolymer produced by reacting an aromatic dihydroxy compound and a diaryl carbonate using a guide contact flow type polymerizer, but the present embodiment is not limited to the method described below.
The aromatic dihydroxy compound used in the production of the aromatic polycarbonate is a compound represented by formula (7).
HO-Ar-OH (7)
(wherein Ar represents a 2-valent aromatic group.)
The aromatic group Ar having a valence of 2 is preferably, for example, a group represented by the formula (8).
-Ar1-Y-Ar2- (8)
(wherein Ar is1And Ar2Each independently represents a carbon number of 5 to 70A 2-valent carbocyclic or heterocyclic aromatic group, and Y represents a 2-valent alkyl group having 1 to 30 carbon atoms. )
2-valent aromatic radical Ar1、Ar2In the above reaction, 1 or more hydrogen atoms may be substituted with another substituent which does not affect the reaction, for example, a halogen atom, an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, a phenyl group, a phenoxy group, a vinyl group, a cyano group, an ester group, an amide group, a nitro group or the like. As a heterocyclic aromatic group preferred specific example, can be cited has 1 or 2 or more ring-forming nitrogen atoms, oxygen atoms or sulfur atoms of aromatic groups. 2-valent aromatic radical Ar1、Ar2For example, a substituted or unsubstituted phenylene group, a substituted or unsubstituted biphenylene group, a substituted or unsubstituted pyridylene group or the like is mentioned. The substituents herein are as described above.
The alkyl group Y having a valence of 2 is, for example, an organic group represented by the following formula.
[ CHEM 11 ]
(in the formula, R1、R2、R3、R4Each independently represents hydrogen, an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, a cycloalkyl group having 5 to 10 ring-forming carbon atoms, a carbocyclic aromatic group having 5 to 10 ring-forming carbon atoms, or a carbocyclic aralkyl group having 6 to 10 carbon atoms. k represents an integer of 3 to 11, R5And R6Each X is independently selected from hydrogen and alkyl having 1 to 6 carbon atoms, and X is carbon. In addition, in R1、R2、R3、R4、R5、R6In the above reaction, 1 or more hydrogen atoms may be substituted with other substituent(s), for example, a halogen atom, an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, a phenyl group, a phenoxy group, a vinyl group, a cyano group, an ester group, an amide group, a nitro group, or the like, within a range not affecting the reaction. )
Examples of the 2-valent aromatic group Ar include groups represented by the following formula.
[ CHEM 12 ]
(in the formula, R7、R8Each independently represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, a cycloalkyl group having 5 to 10 ring-forming carbon atoms or a phenyl group, m and n are integers of 1 to 4, and when m is 2 to 4, each R is7Each may be the same or different, and when n is 2 to 4, R8Each may be the same or different. )
In addition, the 2-valent aromatic group Ar may be a group represented by the following formula.
-Ar1-Z-Ar2-
(wherein Ar is1And Ar2As mentioned above, Z represents a single bond or-O-, -CO-, -S-, -SO2-、-SO-、-COO-、-CON(R1) An equivalent 2-valent radical. R1As described above. )
Examples of the 2-valent aromatic group Ar include groups represented by the following formula.
[ CHEM 13 ]
(in the formula, R7、R8M and n are as described above. )
Specific examples of the aromatic group Ar having a valence of 2 include a substituted or unsubstituted phenylene group, a substituted or unsubstituted naphthylene group, a substituted or unsubstituted pyridylene group and the like.
The aromatic dihydroxy compound may be one kind alone or two or more kinds. Typical examples of the aromatic dihydroxy compound include bisphenol a and 2, 2-bis (3-methyl-4-hydroxyphenyl) propane. Further, as the aromatic dihydroxy compound, a 3-valent aromatic trihydroxy compound for introducing a branched structure may be used in combination.
In the production process of the aromatic polycarbonate, the ratio of the aromatic dihydroxy compound to the diaryl carbonate (charging ratio) may be adjusted depending on the kind of the aromatic dihydroxy compound and the diaryl carbonate to be used, the polymerization conditions such as the polymerization temperature, and the like, and the diaryl carbonate is used in a ratio of usually 0.9 to 2.5 mol, preferably 0.95 to 2.0 mol, and more preferably 0.98 to 1.5 mol, based on 1 mol of the aromatic dihydroxy compound.
The molten prepolymer in the production process of the aromatic polycarbonate is a melt during polymerization having a lower polymerization degree than the aromatic polycarbonate having a target polymerization degree, and may be an oligomer. Since the mixture of the aromatic dihydroxy compound and the diaryl carbonate can be reacted only by heating and melting, the mixture is substantially a molten prepolymer. The number average molecular weight of the molten prepolymer used in the production process of the aromatic polycarbonate is not particularly limited as long as it is molten at the polymerization temperature, and the number average molecular weight varies depending on the chemical structure. The number average molecular weight of the molten prepolymer is preferably 500 to 100,000, more preferably 500 to 10,000, and still more preferably 1,000 to 8,000.
The material of the polymerization vessel and other reactors in the production process of the aromatic polycarbonate is not particularly limited, and the material constituting at least the inner wall surface of the polymerization vessel or the reactors may be a material selected from stainless steel, nickel, glass, and the like.
The molten prepolymer used in the production process of the aromatic polycarbonate can be obtained by any known method. For example, it can be produced as follows: the molten prepolymer is produced by using 1 or more vertical stirring tanks and removing the aromatic monohydroxy compound by-produced during the reaction while stirring a molten mixture of a predetermined amount of an aromatic dihydroxy compound and a diaryl carbonate under normal pressure and/or reduced pressure at a temperature ranging from about 120 ℃ to about 280 ℃. The following methods are particularly preferred: a molten prepolymer having a desired polymerization degree is continuously produced by using 2 or more vertical stirring tanks connected in series and sequentially increasing the polymerization degree.
In the aromatic polycarbonate production step, the molten prepolymer is preferably continuously fed to a guide contact flow type polymerizer to continuously produce an aromatic polycarbonate having a desired degree of polymerization. The guide-contact flow-down type polymerizer is a polymerizer which polymerizes a prepolymer by causing the prepolymer to melt and flow down along a guide constituted by a vertical line, and examples thereof include those disclosed in international publication No. 2005/121210, international publication No. 2005/121211, international publication No. 2012/056903, international publication No. 2015/141501, and the like.
In the aromatic polycarbonate production step, the temperature of the reaction for producing an aromatic polycarbonate by polymerizing a molten prepolymer obtained from an aromatic dihydroxy compound and a diaryl carbonate in a guide contact flow down type polymerizer is preferably 80 to 350 ℃, more preferably 100 to 290 ℃, and still more preferably 150 to 270 ℃.
In the production process of an aromatic polycarbonate, the reaction pressure in the polymerization vessel can be adjusted by the kind or molecular weight of the aromatic polycarbonate to be produced, the polymerization temperature, and the like, and for example, when a molten prepolymer is obtained from bisphenol A and diphenyl carbonate and an aromatic polycarbonate is produced from the molten prepolymer, the reaction pressure in the range of 5,000 or less in number average molecular weight is preferably 400Pa to 3,000Pa, and the reaction pressure in the range of 5,000 to 10,000 in number average molecular weight is preferably 50Pa to 500 Pa. When the number average molecular weight is 10,000 or more, the reaction pressure is preferably 300Pa or less, more preferably 20Pa to 250 Pa.
In the production process of an aromatic polycarbonate, an aromatic monohydroxy compound is gradually produced as the polymerization reaction proceeds, and the reaction rate is increased by removing the aromatic monohydroxy compound out of the reaction system. Therefore, the following method is preferably used: a method in which an inert gas such as nitrogen, argon, helium, carbon dioxide, or a lower hydrocarbon gas which does not affect the reaction is introduced into a polymerization reactor, and an aromatic monohydroxy compound which is gradually produced is removed together with these gases; a method of carrying out the reaction under reduced pressure; and so on. In these cases, it is not necessary to introduce a large amount of inert gas into the polymerization reactor, and the inside may be maintained in an inert gas atmosphere.
The following methods are also preferable: the inert gas is absorbed before the molten prepolymer is supplied to the guide contact flow-down type polymerizer, and the inert gas-absorbed molten prepolymer is polymerized.
When the aromatic polycarbonate production process is carried out, an aromatic polycarbonate having a desired degree of polymerization can be produced by only 1 guide-contact flow type polymerizer, and the following is also preferred: a plurality of guide contact flow type polymerizers having 2 or more units are connected in order to increase the polymerization degree in sequence depending on the polymerization degree of the raw material molten prepolymer, the amount of the aromatic polycarbonate produced, and the like. In this case, it is preferable to use a guide and reaction conditions suitable for the polymerization degree of the prepolymer or the aromatic polycarbonate to be produced in each polymerization vessel.
In the aromatic polycarbonate production step, the reaction for producing an aromatic polycarbonate from an aromatic dihydroxy compound and a diaryl carbonate may be carried out without adding a catalyst, or the reaction may be carried out in the presence of a catalyst as necessary in order to increase the polymerization rate.
The catalyst used in the reaction for producing an aromatic polycarbonate is not particularly limited as long as it is a catalyst used in the field, and the following catalysts may be mentioned: hydroxides of alkali metals and alkaline earth metals such as lithium hydroxide, sodium hydroxide, potassium hydroxide, and calcium hydroxide; alkali metal salts, alkaline earth metal salts, and quaternary ammonium salts of boron or aluminum hydrides such as lithium aluminum hydride, sodium borohydride, and tetramethylammonium borohydride; hydrogen compounds of alkali metals and alkaline earth metals such as lithium hydride, sodium hydride, and calcium hydride; alkali metal and alkaline earth metal alkoxides such as lithium methoxide, sodium ethoxide, and calcium methoxide; lithium phenolate, sodium phenolate, magnesium phenolate, LiO-Ar7-OLi、NaO-Ar7-ONa(Ar7Aryl) etc. alkali goldPhenolates of the genus and alkaline earth metals; organic acid salts of alkali metals and alkaline earth metals such as lithium acetate, calcium acetate, sodium benzoate, etc.; zinc compounds such as zinc oxide, zinc acetate, and zinc phenoxide; boric oxide, boric acid, sodium borate, trimethyl borate, tributyl borate, triphenyl borate, (R)1R2R3R4)NB(R1R2R3R4) Or (R)1R2R3R4)PB(R1R2R3R4) Ammonium borate salts or phosphonium borate salts (R)1、R2、R3、R4Boron compounds such as those described above); silicon compounds such as silicon oxide, sodium silicate, tetraalkyl silicon, tetraaryl silicon, diphenylethyl ethoxy silicon and the like; germanium compounds such as germanium oxide, germanium tetrachloride, germanium ethoxide, germanium phenoxide and the like; tin compounds such as tin oxide, dialkyltin carboxylate, tin acetate, tin tributylate, tin compounds bonded with alkoxy group or aryloxy group, and organotin compounds; lead compounds such as lead oxide, lead acetate, lead carbonate, basic carbonate, alkoxide or aryloxide salts of lead and organolead; onium compounds such as quaternary ammonium salts, quaternary phosphonium salts, and quaternary arsenium salts; antimony compounds such as antimony oxide and antimony acetate; manganese compounds such as manganese acetate, manganese carbonate and manganese borate; titanium compounds such as titanium oxide and titanium alkoxides and titanium aryloxides; zirconium compounds such as zirconium acetate, zirconium oxide, alkoxides or aryloxides of zirconium, and zirconium acetylacetonate; and so on.
When a catalyst is used, only 1 kind of the catalyst may be used, or 2 or more kinds may be used in combination. The amount of the catalyst to be used is preferably 10% based on the aromatic dihydroxy compound as the raw material-10Mass% to 1 mass%, more preferably 10-9Mass% to 10-1Further preferably 10% by mass-8Mass% to 10-2The mass% range is selected. In the case of the melt transesterification method, the polymerization catalyst used remains in the product aromatic polycarbonate, and these polymerization catalysts often have an influence on the polymer properties. Therefore, the amount of the catalyst to be used is preferably suppressed as much as possible.
In the production process of an aromatic polycarbonate, a large amount of an aromatic monohydroxy compound produced as a by-product of the reaction is usually continuously withdrawn in a gaseous state, and preferably condensed into a liquid state and recovered, at the time of producing a molten prepolymer or at the time of polymerization by a guide contact flow type polymerizer or the like. It is preferable to perform the aromatic monohydroxy compound recycling step so that the aromatic monohydroxy compound by-produced in the aromatic polycarbonate production step is recycled in the diaryl carbonate production step. In an industrial production process, it is important to recover the total amount or loss of the aromatic monohydroxy compound produced as a by-product as little as possible and recycle and reuse the recovered aromatic monohydroxy compound.
The aromatic monohydroxy compound by-produced and recovered in the production process of an aromatic polycarbonate may contain a part of the diaryl carbonate, and since the purity thereof is high, it may be directly recycled in the production process of the diaryl carbonate. When a small amount of the aromatic dihydroxy compound or a small amount of the oligomer is mixed with the recovered aromatic monohydroxy compound, it is preferable to further perform distillation to remove these high boiling point substances and then recycle them to the diaryl carbonate production step.
The aromatic polycarbonate produced in the aromatic polycarbonate production step has a repeating unit represented by the following formula (9).
[ CHEM 14 ]
(Ar is the same as defined above.)
The aromatic polycarbonate is preferably an aromatic polycarbonate containing 85 mol% or more of a repeating unit represented by the following formula (10) in all repeating units.
[ CHEM 15 ]
The terminal group of the aromatic polycarbonate is usually composed of a hydroxyl group or an aryl carbonate group represented by the following formula (11).
[ CHEM 16 ]
(Ar6Is the same as Ar above3、Ar4The same definition. )
The ratio of hydroxyl groups to arylcarbonate groups is not particularly limited, and is usually 95: 5-5: 95, preferably 90: 10-10: range of 90, more preferably 80: 20-20: 80 in the above range. The aromatic polycarbonate is more preferably an aromatic polycarbonate in which the proportion of carbonate groups in the terminal groups is 60 mol% or more.
In the aromatic polycarbonate produced as described above, the aromatic polycarbonate may be partially branched in the main chain by a different bond such as an ester bond or an ether bond. The amount of the above-mentioned hetero bond is usually 0.005 to 2 mol%, preferably 0.01 to 1 mol%, and more preferably 0.05 to 0.5 mol% based on the carbonate bond. Such an amount of the hetero bond improves the flow characteristics at the time of melt molding without deteriorating the physical properties of other polymers, and is therefore suitable for precision molding, and can be molded even at a relatively low temperature, thereby enabling production of a molded article having excellent properties. It can also shorten the molding cycle and contribute to energy saving during molding.
Examples
The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to the following examples.
[ example 1]
A reaction distillation was performed using an apparatus in which a 1 st continuous multi-stage distillation column 101, a 2 nd continuous multi-stage distillation column 102, and a 3 rd continuous multi-stage distillation column 103 were connected as shown in the flow chart of fig. 1, to produce diphenyl carbonate.
[1 st continuous multistage distillation column 101]
A continuous multi-stage distillation column was used comprising a recovery section of length 17m and internal diameter 1.8m with 16 stages of internals in the interior and a concentrate section of length 25m and internal diameter 1m with 55 stages of internals in the interior. The cross-sectional area of the internal member in the recovery part and the concentration part is about 1.3cm per 1 hole2The number of holes is about 550/m2Perforated plate trays of (1).
[2 nd continuous multistage distillation column 102]
A continuous multi-stage distillation column having a length of 33m and an internal diameter of 5m and having 80 stages of internals therein was used. The cross-sectional area of the internal member per 1 hole is about 1.5cm2The number of pores is about 250/m2Perforated plate trays of (1).
[3 rd continuous multistage distillation column 103]
A continuous multi-stage distillation column having a length of 31m and an internal diameter of 5m and having 30 stages of internals therein was used. As an internal material, 2 pieces (11 stages in total of theoretical plate numbers) of orifice plate corrugated packings (Mellapak) as a regular packing were provided in the upper part, and the cross-sectional area per 1 orifice was set to about 1.3cm in the lower part2The number of pores is about 250/m2Perforated plate trays of (1).
Into a 1 st continuous multi-stage distillation column 101, dimethyl carbonate (100% by mass) to which 12 ppm by mass of 1, 1-dimethoxypropane and 80 ppm by mass of 2, 2-dimethoxypropane were added was charged at 2.5 ton/hr through a line 1, and the pressure at the top of the column was 10X 105The distillation operation was continuously carried out under the conditions of Pa and a reflux ratio of 2.9.
A low boiling point reaction mixture containing methanol (100 mass%) and 7 mass ppm of aldehydes and ketones produced by the reaction of 1, 1-dimethoxypropane, 2-dimethoxypropane and water was withdrawn from the top 5 of the 1 st continuous multi-stage distillation column 101 at 1.8 ton/hr.
A high boiling point reaction mixture containing dimethyl carbonate (71 mass%), phenol (29 mass%), unreacted 1, 1-dimethoxypropane (2 mass ppm) and 2, 2-dimethoxypropane (14 mass ppm) was withdrawn from the bottom 2 of the 1 st continuous multi-stage distillation column 101 at 35 tons/hr and charged into the 2 nd distillation column 102.
Introduction of catalyst Ti (OPh) into the 2 nd continuous multi-stage distillation column 1024So that the Ti concentration in the reaction solution at the bottom of the 2 nd continuous multi-stage distillation column 102 is about 150 ppm by mass, the temperature at the bottom of the column is 226 ℃ and the pressure at the top of the column is 7X 105Pa and a reflux ratio of 0.
Aldehydes and ketones generated by the reaction of 1, 1-dimethoxypropane, 2-dimethoxypropane and water were removed as a gas by venting from the column top 4 of the 2 nd continuous multi-stage distillation column 102, and a low boiling point reaction mixture containing methanol (5 mass%), dimethyl carbonate (65 mass%), phenol (30 mass%), 1-dimethoxypropane (2 mass ppm), 2-dimethoxypropane (9 mass ppm) and water (1 mass ppm) was withdrawn at a flow rate of 34 tons/hour and charged into the 1 st continuous multi-stage distillation column 101.
From the column bottom 3 of the 2 nd continuous multi-stage distillation column 102, a high boiling point reaction mixture containing dimethyl carbonate (29 mass%), phenol (59 mass%), methyl phenyl carbonate (12 mass%), 1-dimethoxypropane (1 mass ppm), 2-dimethoxypropane (6 mass ppm) was withdrawn at a flow rate of 66 tons/hr and charged into the 3 rd continuous multi-stage distillation column 103. The raw material phenol (100 mass%) was charged through a line 8 at a rate of 5.2 ton/hr. The starting phenol contained 10 mass ppm of water.
In the 3 rd continuous multi-stage distillation column 103, a catalyst Ti (OPh)4Introduced into the 3 rd distillation column 103 so that the Ti concentration in the reaction solution at the bottom of the 3 rd continuous multi-stage distillation column 103 is about 1600 ppm by mass, the temperature at the bottom is 205 ℃ and the pressure at the top is 3X 104Pa and a reflux ratio of 0.25.
Aldehydes and ketones generated by the reaction of 1, 1-dimethoxypropane, 2-dimethoxypropane and water were removed as a gas by venting from the column top 7 of the 3 rd continuous multi-stage distillation column 103, and a low boiling point reaction mixture containing dimethyl carbonate (33 mass%), phenol (67 mass%), 1-dimethoxypropane (1 mass ppm), 2-dimethoxypropane (5 mass ppm) and water (1 mass ppm) was withdrawn at a flow rate of 65 tons/hr and charged into the 2 nd continuous multi-stage distillation column 102. The feeding of the low-boiling point reaction mixture into the 2 nd continuous multi-stage distillation column 102 is carried out as follows: the low boiling point reaction mixture is withdrawn through a line 7 at the top of the column 7, and a line 8 for charging the raw material phenol is joined to the line 7 and fed through a line 9.
A high boiling point reaction mixture containing methylphenyl carbonate (44 mass%) and diphenyl carbonate (56 mass%) was continuously withdrawn at 6.6 t/hr from the bottom 6 of the 3 rd continuous multi-stage distillation column 103. The amount of diphenyl carbonate produced was 5.7 ton/hr in terms of diphenyl carbonate as the amount of methyl phenyl carbonate. Continuous operation was stably performed for 5,000 hours under these conditions.
[ example 2]
Diphenyl carbonate was produced under the same conditions as those of the apparatus and operation in example 1 except that the contents of 1, 1-dimethoxypropane and 2, 2-dimethoxypropane in dimethyl carbonate charged through line 1 were changed.
Dimethyl carbonate produced by the PO method was used as dimethyl carbonate charged through line 1. In this case, in the PO method, dimethyl carbonate is synthesized under conditions more increased in the production of 1, 1-dimethoxypropane and 2, 2-dimethoxypropane. Specifically, in the PO method, the synthesis reaction of dimethyl carbonate is carried out under the condition that the catalyst concentration in the dimethyl carbonate synthesis reactor is 2 times the concentration of the catalyst in the reactor. As a result, 1-dimethoxypropane and 2, 2-dimethoxypropane were produced in larger amounts as by-products than usual, and 20 ppm by mass of 1, 1-dimethoxypropane and 90 ppm by mass of 2, 2-dimethoxypropane were contained in dimethyl carbonate.
The amount of diphenyl carbonate produced was 5.7 tons/hr, which is not different from example 1. Continuous operation was stably carried out for 1,000 hours under these conditions.
Comparative example 1
The operation was carried out under the same conditions as in example 1 except that 1, 1-dimethoxypropane and 2, 2-dimethoxypropane were not added to dimethyl carbonate charged through the line 1 of the 1 st continuous multi-stage distillation column 101, whereby the amount of diphenyl carbonate produced was reduced to 4.5 ton/hr. This is considered to be because the catalyst activity is lowered by the action of water which is not removed from the diaryl carbonate production process. The continuous operation was stably carried out under these conditions for 1,000 hours.
Comparative example 2
An operation was carried out under the same conditions as in example 1 except that 1 mass% of 1, 1-dimethoxypropane and 1 mass% of 2, 2-dimethoxypropane were added to dimethyl carbonate charged through the line 1 of the 1 st continuous multi-stage distillation column 101 using the same apparatus as in example 1. The amount of diphenyl carbonate produced was 5.7 tons/hr, which was not decreased as compared with examples 1 and 2, but 100 mass ppm of impurities such as 9, 9-dimethylxanthene produced by the reaction of 1, 1-dimethoxypropane, 2-dimethoxypropane and phenol were mixed into diphenyl carbonate.
[ reference example 1]
A molten prepolymer was produced using bisphenol A and the diphenyl carbonate obtained in example 1 as raw materials, and an aromatic polycarbonate was produced using a guide contact flow type polymerizer. The outer shell of the guide contact flow type polymerizer had an inner diameter of 1.5m and a length of 10m, and 180 vertical lines having a diameter of 3mm and a length of 9m were provided inside the guide contact flow type polymerizer.
A molten prepolymer, which was prepared from bisphenol A and the diphenyl carbonate obtained in example 1 (molar ratio relative to bisphenol A: 1.08), and had a number average molecular weight of 5,000 and was maintained at 265 ℃ was continuously fed to the above-mentioned guide contact flow type polymerizer, and polymerization was carried out at 265 ℃ and a pressure of 50 Pa. The molten prepolymer continuously fed flowed down along the vertical line, and polymerization was carried out therewith to produce an aromatic polycarbonate having a number average molecular weight of 13,000.
The obtained aromatic polycarbonate was injection-molded into a flat plate having a thickness of 3.2mm under the conditions of a cylinder temperature of 300 ℃ and a mold temperature of 90 ℃, the plate was placed on a white color correction plate using CR-400 manufactured by konica minolta corporation and measured by a reflection method (measurement diameter 8mm), and the hue (Δ b) was determined from the difference between the b value of the white color correction plate (the b value of the flat plate is the measurement value of the white color correction plate in which the flat plate is placed on the white color correction plate — the measurement value of the white color correction plate), and the hue was determined (the smaller the hue value is, the better the hue is). The color number was 0.1.
[ reference example 2]
An aromatic polycarbonate was produced in the same manner as in reference example 1, except that diphenyl carbonate was used as the diphenyl carbonate obtained in example 2.
A molten prepolymer having a number average molecular weight of 5,000 was produced from bisphenol a and diphenyl carbonate (molar ratio to bisphenol a: 1.08) obtained in example 2, and this molten prepolymer was continuously fed to the above-mentioned guide contact flow type polymerizer to produce an aromatic polycarbonate having a number average molecular weight of 13,000.
The chroma of the obtained aromatic polycarbonate was determined to be 0.1, which was the same as the hue of the aromatic polycarbonate of reference example 1.
[ comparative reference example 3]
An aromatic polycarbonate was produced in the same manner as in reference example 1, except that diphenyl carbonate was used as the diphenyl carbonate obtained in comparative example 2.
A molten prepolymer having a number average molecular weight of 5,000 was produced from bisphenol A and diphenyl carbonate (molar ratio to bisphenol A: 1.08) obtained in comparative example 2, and this molten prepolymer was continuously fed to the above-mentioned guide contact flow type polymerizer to produce an aromatic polycarbonate having a number average molecular weight of 13,000.
The hue of the obtained aromatic polycarbonate was determined to be 0.7, which was inferior to the hue of the aromatic polycarbonate of reference example 1.
Industrial applicability
According to the present invention, water which causes deterioration of a catalyst in a diaryl carbonate production process can be easily removed without using a special apparatus, and therefore, the present invention has industrial applicability in the production of diaryl carbonates.
Claims (7)
1. A process for producing a diaryl carbonate from an aromatic monohydroxy compound and a dialkyl carbonate containing a compound represented by the following formula (1) in the presence of a catalyst,
[ CHEM 1]
In the formula (1), R1, R2 and R4 independently represent a chain alkyl group, an alkenyl group and an alkynyl group having 1 to 6 carbon atoms, R3 represents a hydrogen atom or a chain alkyl group, an alkenyl group and an alkynyl group having 1 to 6 carbon atoms,
wherein the content of the first and second substances,
the dialkyl carbonate contains a compound represented by the formula (1) other than 1, 1-dimethoxyethane in an amount of 1 to 1000 mass ppm based on the dialkyl carbonate as a raw material,
the method comprises the following steps:
a step of feeding a dialkyl carbonate containing 1 to 1000 mass ppm of a compound represented by formula (1) into a 1 st continuous multi-stage distillation column, continuously distilling the dialkyl carbonate, withdrawing aldehydes and/or ketones generated by the reaction of the compound represented by formula (1) with water from the top of the column, and withdrawing a mixture containing the dialkyl carbonate and the compound represented by formula (1); and
a step of continuously supplying the mixture obtained in the step and an aromatic monohydroxy compound into a 2 nd continuous multi-stage distillation column in which a catalyst is present, and reacting the dialkyl carbonate and the aromatic monohydroxy compound in the 2 nd continuous multi-stage distillation column,
and the number of the first and second electrodes,
the catalyst is selected from PbO, Pb (OH)2、Pb(OPh)2；TiCl4、Ti(OMe)4、(MeO)Ti(OPh)3、(MeO)2Ti(OPh)2、(MeO)3Ti(OPh)、Ti(OPh)4；SnCl4、Sn(OPh)4、Bu2SnO、Bu2Sn(OPh)21 or more of the group.
2. The method for producing a diaryl carbonate according to claim 1, wherein the compound represented by the formula (1) is a dialkoxyalkane.
3. The method for producing a diaryl carbonate according to claim 2, wherein the dialkoxyalkane is dimethoxypropane.
4. The method for producing a diaryl carbonate according to any one of claims 1 to 3, wherein the dialkyl carbonate is dimethyl carbonate.
5. The process for producing a diaryl carbonate according to any one of claims 1 to 3, further comprising:
continuously withdrawing a 2 nd high boiling point reaction mixture containing alkyl aryl carbonates from the lower part of the 2 nd continuous multi-stage distillation column in a liquid state, continuously supplying the 2 nd high boiling point reaction mixture to a 3 rd continuous multi-stage distillation column connected to the 2 nd continuous multi-stage distillation column in the presence of a catalyst, and reacting in the 3 rd continuous multi-stage distillation column to produce dialkyl carbonates and diaryl carbonates,
in the step, the catalyst is selected from PbO and Pb (OH)2、Pb(OPh)2；TiCl4、Ti(OMe)4、(MeO)Ti(OPh)3、(MeO)2Ti(OPh)2、(MeO)3Ti(OPh)、Ti(OPh)4；SnCl4、Sn(OPh)4、Bu2SnO、Bu2Sn(OPh)21 or more of the group.
6. A method for producing an aromatic polycarbonate, comprising the steps of:
a step of obtaining a diaryl carbonate by the method according to any one of claims 1 to 5; and
and a step of reacting the obtained diaryl carbonate with an aromatic dihydroxy compound.
7. The method for producing an aromatic polycarbonate according to claim 6, wherein the aromatic monohydroxy compound contains a by-product obtained by a reaction between the diaryl carbonate and the aromatic dihydroxy compound.
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| KR101978568B1 (en) | 2019-05-14 |
| CN108586254A (en) | 2018-09-28 |
| KR20180091682A (en) | 2018-08-16 |
| JP6347859B1 (en) | 2018-06-27 |
| JP2018127404A (en) | 2018-08-16 |
| CN108395374A (en) | 2018-08-14 |
| CN108586254B (en) | 2021-06-18 |
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