JPH05148189A - Production of aromatic carbonic acid esters - Google Patents

Abstract

PURPOSE:To obtain the subject compound useful as a raw material for polycarbonate resin, etc., in high selectivity and in high yield by subjecting a carbonic acid dialkyl ester, etc., to ester exchange reaction in the presence of a specific catalyst. CONSTITUTION:A carbonic acid dialkyl ester or a carbonic acid alkyl aryl ester is subjected to ester exchange reaction by using a catalyst which is pretreated by heating at 120-250 deg.C in the presence of 3-100 molar times a phenol and 1-20 molar times a carbonic acid dialkyl ester and/or a carbonic acid alkyl aryl ester of a catalyst as a treatment before reaction and comprises one or more compounds of element selected from rare earth elements such as Yb, Tm, Ho, Dy, Tb, Sm, Nd and Pr as the catalyst.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for producing carbonic acid esters by a transesterification method. More specifically, a method for producing a carbonic acid alkylaryl ester and / or a carbonic acid diaryl ester by reacting a carbonic acid dialkyl ester with a phenol and its acyl ester in the presence of a specific catalyst, or a carbonic acid alkylaryl ester and a phenol And a method for producing carbonic acid diaryl esters from the acyl esters thereof. Carbonic acid diaryl esters, such as diphenyl carbonate, are industrially important as raw materials for polycarbonate resins and the like.

[0002]

2. Description of the Related Art There are various methods for producing carbonic acid alkylaryl esters and / or carbonic acid diaryl esters by transesterification of phenols and their acyl esters with carbonic acid dialkyl esters or carbonic acid alkylaryl esters. It is disclosed in. The transesterification reaction represented by the chemical formulas (I, II) is an equilibrium reaction (in the formulas I and II, X is hydrogen or an acyl group), but the elimination occurs in the reaction transition state in the formula. Highly functional aryloxy group (ArO-)
However, since the elimination is performed in preference to the alkoxy group (RO-) to give a product (Ar represents an aryl group and R represents an alkyl group), the equilibrium reaction is largely biased to the raw material system. Therefore,
These transesterification reactions also have a very slow reaction rate,
It also has a problem that the product yield is very low.

[0003]

[Chemical 1]

[0004]

[Chemical 2]

To promote such a transesterification reaction,
In order to carry out the desired product in high yield and high selectivity, known techniques are for carrying out a nucleophilic reaction to a carbonyl group of a carbonic acid dialkyl ester or a carbonic acid alkylaryl ester of a phenol and its acyl ester. In addition, it is common to use a catalyst that increases the reaction rate. The use of catalysts in the known art is disclosed in the following publications. In JP-A-51-105032, Ti is used.
System, Al system, Pb system of JP-A-57-176932, Sn system of JP-A-60-169444, etc., but most of them have the reaction activity of the catalyst or the yield and selectivity of the target product. There is a problem that it is low. Further, in Japanese Patent Application Laid-Open No. 1-265064, lanthanoid series and S
c, Cr, Mo, W, Mn, Au, Ga, In, Bi,
Although various catalyst systems such as Te are shown, in addition to the fact that the temperature and pressure of the reaction conditions are high and the reaction conditions are severe,
There is a problem that the catalytic activity, the yield of the target product and the selectivity are low.

[0006]

DISCLOSURE OF THE INVENTION The present inventors have diligently studied the above problems, and in the transesterification reaction of phenols and their acyl esters with carbonic acid dialkyl esters or carbonic acid alkylaryl esters, the formation of the desired product The present invention has been accomplished by studying catalysts and reaction conditions with high yield of products and high selectivity, and finding catalysts and reaction conditions with which high effects can be obtained.

[0007]

Means for Solving the Problems In order to find a more industrially advantageous production method, the present inventors have conducted diligent research to solve the above-mentioned problems, and have a high yield and a high selectivity of a reaction target substance. The present invention is achieved by finding the catalyst and the reaction conditions obtained in the above. The present invention provides a method for producing an aromatic carbonic acid ester, which comprises transesterifying a carbonic acid dialkyl ester or a carbonic acid alkylaryl ester with a phenol or its acyl ester in the presence of a compound of a rare earth element as a catalyst. A compound in which the alkyl group is a lower aliphatic group having 1 to 4 carbon atoms and the aryl group is a phenyl group or a substituted phenyl group having 7 to 15 carbon atoms, and a rare earth element Yb, Tm, H is used as a catalyst.
o, Dy, Tb, Sm, Nd, Pr, a compound of one or more elements selected from the above is used, and as a reaction pretreatment, 3 to 100 moles of phenols and In the presence of 20 times moles of carbonic acid dialkyl esters and / or carbonic acid alkylaryl esters,
A carbonic acid alkylaryl ester characterized by being produced by further adding a raw material of a carbonic acid dialkylester and / or a carbonic acid alkylaryl ester by using the catalyst pretreated by heating at 120 to 250 ° C. and carrying out a transesterification reaction. And a method for producing carbonic acid diaryl esters.

Next, a detailed description of the present invention will be given below.
The phenols used in the present invention are those represented by Ar-OH. The Ar (aryl group) used here is, in addition to an unsubstituted aromatic group such as phenyl, naphthyl and pyridine, a substituted aromatic group represented by the following formula (III) (where R ′ is a lower alkyl group, Alkoxy group, aryloxy group, nitro group, cyano group, formyl group, aromatic group,
When a substituent such as halogen is shown, 1 is an integer of 1 to 5, m is an integer of 1 to 7, n is an integer of 1 to 4, and when l, m and n are 2 or more, R ′ is the same. It doesn't matter if they are different. ).

[0009]

[Chemical 3]

Phenols as specific raw materials include phenol, o, m, p-chlorophenol, methylchlorophenol, dimethylphenol, dimethylchlorophenol, cresol, o, m, p-phenoxyphenol, o, m, p-nitrophenol, o, m, p-cyanophenol, o, m, p-phenylphenol,
o, m, p-ethylphenol, o, m, p-butylphenol, o, m, p-methoxyphenol, o, m,
p-Cresol, dibutylphenol, 8-naphthol, 2-naphthol, 2-pyridinol, 3-pyridinol are used. Phenol is particularly preferable.

The acyl ester of phenol as a specific raw material used in the present invention is represented by the general formula Ar-O-COR ". Here, Ar is the same as described above, but R ″ is an alkyl group containing isomers such as methyl, ethyl, propyl, butyl, pentyl, and hexyl, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, methylcyclohexyl, methyl. A cycloalkyl group such as cyclobutyl and cyclohexylmethyl, an aromatic alkyl group such as benzyl and phenethyl, and hydrogen. Specific examples of the acyl ester of phenol as a raw material include formic acid ester, acetic acid ester, propionic acid ester, butyric acid ester, isobutyric acid ester, and valeric acid ester. Phenyl formate and phenyl acetate are particularly preferable.

The carbonic acid dialkyl ester as a specific raw material used in the present invention is represented by the general formula R--O.
-CO ₂ · R ″. Where R is
It is an alkyl group including isomers such as methyl, ethyl, propyl, butyl, allyl and butenyl. R ″ is the same as described above, and R and R ″ may be the same or different. Specifically, dimethyl carbonate, diethyl carbonate, dipropyl carbonate, diisopropyl carbonate, diallyl carbonate, dinormal butyl carbonate, disec-butyl carbonate,
These are di-tert-butyl carbonate and ethylene carbonate. Dimethyl carbonate is particularly preferable.

Carbonic acid alkyl aryl esters as specific raw materials used in the present invention are represented by the general formula R--O--C.
It is represented by O ₂ · Ar. Where R and Ar
Is the same as above. Specifically, methylphenyl carbonate, ethylphenyl carbonate, propylphenyl carbonate, isopropylphenyl carbonate, normal butylphenyl carbonate, sec-butylphenyl carbonate, tert-butylphenyl carbonate, allylphenyl carbonate, methyltolyl carbonate, ethyl tolyl carbonate. is there.
Particularly preferred is methylphenyl carbonate.

The carbonic acid diaryl esters, which are the desired products of the present invention, are represented by the general formula Ar--O--CO ₂ .Ar. Ar here is also the same as above.
Specifically, they are diphenyl carbonate, ditolyl carbonate, di (chlorophenyl) carbonate, di (methylphenyl) carbonate, and dinaphthyl carbonate.

The catalyst of the present invention comprises rare earth elements Yb and T.
A compound of one or more elements selected from m, Ho, Dy, Tb, Sm, Nd and Pr is used. Examples of these catalyst compounds include halides, oxides, hydrides, alkoxy compounds, sulfuric acid compounds, nitric acid compounds, acetylacetonato compounds, cyclopentadienyl compounds, carbonyl compounds, cyano compounds, alkyl compounds and phosphines of the above elements. Used as a complex, an amine complex, an ether complex, etc., and a carboxylic acid compound is excluded because it has no effect. These may be hydrates or anhydrides, but anhydrides are preferred. These compounds may be used alone or in combination of two or more.

As the above-mentioned catalyst, specifically, PrC
l ₃ , Pr (NO ₃ ) ₃ , Pr ₂ (SO ₄ ) ₃ , Pr
(Thd) ₃ (thd = 1,2,2,6,6-tetramethyl-3,5-heptanedionato), Pr (fod) ₃
(Fod = 6,6,7,7,8.8.8-hetafluoro-2,2-dimethyl-3,5-octanedionate), N
dCl ₃ , NdF ₃ , Nd (NO ₃ ) ₃ , Nd ₂ O ₃ ,
Nd ₂ (SO ₄ ) ₃ , SmCl ₃ , Sm (NO ₃ ) ₃ ,
Sm ₂ O ₃ , Sm ₂ (SO ₄ ) ₃ , TbCl ₃ , Tb
(NO ₃ ) ₃ , Tb ₂ (SO ₄ ) ₃ , DyCl ₃ , Dy
(NO ₃ ) ₃ , Dy ₂ O ₃ , Dy ₂ (SO ₄ ) ₃ , Ho
_{Cl 3, Ho (NO 3)} 3, Ho 2 (SO 4) 3, Ho
₂ O ₃ , Ho (thd) ₃ , Ho (fod) ₃ , TmC
l ₃ , Tm (NO ₃ ) ₃ , Tm ₂ (SO ₄ ) ₃ , Tm ₂
O ₃ , YbCl ₃ , Yb (NO ₃ ) ₃ , Yb ₂ (S
O ₄ ) ₃ , Yb ₂ O ₃ , Yb (thd) ₃ , Yb (fo
d) ₃ is used. Among them, the halogen compound PrCl
_{3, YbCl 3, TmCl 3,} HoCl 3, SmC
I ₃ , NdCl ₃ are preferred.

It is particularly important that the catalyst used in the present invention is subjected to a pretreatment reaction of heating and refluxing in the presence of the above compounds and phenols and a small amount of carbonic acid dialkyl esters. The phenols used for this pretreatment are
It is preferably the same as the raw material used for the transesterification reaction. The addition amount of phenols in the pretreatment is optimally 3 to 100 times mol, preferably 3 to 50 times mol, relative to the amount of catalyst, and when the addition amount is large, carbonic acid dialkyl esters are diluted and the reaction rate is slow, If it is too small, the selectivity will deteriorate. The carbonic acid dialkyl ester used in the pretreatment is also preferably the same as the raw material used in the transesterification reaction.

In the pretreatment reaction, the amount of the carbonic acid dialkyl ester added is optimally 1 to 20 times mol, preferably 1 to 10 times mol, with respect to the amount of catalyst in order to enhance the catalytic activity effect, and the addition amount is small. And the carbonic acid dialkyl ester are diluted, the reaction rate is slow, and if the amount is large, the selectivity deteriorates.
The heating temperature is optimally 120 to 250 ° C., especially 15
0 to 180 ° C. is preferable, and when the reaction temperature is low, the reaction rate is slow, and when it is high, the selectivity deteriorates. Heating reflux time is 0.5
The reaction is carried out for 3 to 3 hours, preferably 1 to 2.5 hours. The reaction time is short, the yield is poor, and the reaction time is long, the selectivity is deteriorated.

In this reaction, the amount of the catalyst used in the transesterification reaction is 10 ^-5 to 2 times the molar ratio of the phenol and its acyl ester, and preferably 10 ^-3 to 10.
The amount is ^-1 times the molar ratio. When the amount is small, the reaction rate is slow, and when the amount is large, the production cost is economically increased, which is not preferable. The charging ratio of the phenols and their acyl esters to the carbonic acid dialkyl esters or carbonic acid alkylaryl esters is optimally in a molar ratio of 50: 1 to 1:50, but in particular 5: 1 to 1: 5. Amount is preferred.

The reaction temperature in this reaction is 120 to 2
Conditions at 50 ° C are possible, and a range of 150 to 200 ° C is particularly preferable. When the temperature is low, the reaction rate is slow, and when the temperature is high, side reactions occur, which is not preferable. The reaction time varies depending on the type of catalyst, the amount of the catalyst used, and the reaction temperature, but is preferably 3 to 24 hours, but from the economical productivity, the reaction time is preferably 3 to 7 hours. .. The reaction may or may not use a solvent in the liquid phase reaction. The reaction pressure can be selected from reduced pressure to increased pressure.

This reaction is an equilibrium reaction as described above,
ROH produced by the equilibrium reaction of transesterification,
Alternatively, it is necessary to remove ROX (R is the same as above and X represents an acyl group) outside the reaction system to form conditions for further shifting the equilibrium to the product system, and therefore distillation is performed. ROH or RO by unit operation
Only X is subjected to reactive distillation, and raw materials for other components are retained in the reaction system by partial condensation. Further, by adding a solvent (an aliphatic hydrocarbon such as hexane, heptane, and cyclohexane, an aromatic hydrocarbon such as benzene) that causes azeotropy with ROH to the reaction system, it is possible to efficiently remove only ROH or ROX. And the equilibrium reaction to the production system can be further promoted.

[0022]

EXAMPLES Next, the present invention will be described more specifically with reference to examples, but the present invention is not limited thereto. Example 1 As a reactor, a 30 ml reactor was placed on top of a 100 ml reactor.
A device equipped with a cm jacketed distillation section, with a thermometer, a reflux section for refluxing the raw material phenol and a condenser section for shunting and condensing the alcohol produced by the evaporated reaction at the top of the distillation section. It was used. Dimethyl carbonate 25 mmol (2.25 g), phenol 50 mmol (4.71 g), YbCl ₃ 2.5 in the reaction vessel.
The catalyst was pretreated by adding mmol (0.70 g), heating the mixture in an oil bath at 170 ° C. under normal pressure, and heating and refluxing for 1.5 hours. After cooling to 60 ° C. or lower, 225 mmol (20.25 g) of dimethyl carbonate was added, and the temperature was raised to 170 ° C. and heated again so that the overhead temperature of the distillation unit did not exceed 80 ° C. while controlling the temperature of the distillation unit. ,
Reactive distillation was performed to distill off methanol produced by the reaction.

After the reaction for 7 hours, the reaction liquid was analyzed by gas chromatography. As a result, the conversion of phenol was 2%.
It was 0.0%, and methylphenyl carbonate (denoted by MPC) and diphenyl carbonate (denoted by DPC) were obtained in yields of 16.4% and 0.7%, respectively, based on phenol. Total yield is 17.1% based on phenol
Met. The overall selection rate of MPC and DPC is 86.0%.
Met. The calculation formulas for the conversion rate, the selectivity, and the yield were calculated by Equation 1, Equation 2, and Equation 3, respectively.

[0024]

[Formula 1]

[0025]

[Formula 2]

[0026]

[Formula 3]

Comparative Example 1 A reaction apparatus similar to that of Example 1 was used, but without heating pretreatment of the catalyst, dimethyl carbonate (DMC) 250 mm
ol (22.5 g), phenol 50 mmol (4.7
1 g) and YbCl ₃ 2.5 mmol (0.70
g) is added, the reactor is heated to 170 ° C. for reaction, and the reaction overhead is distilled while controlling the temperature of the distillation section so that the overhead temperature of the distillation section does not exceed 80 ° C. Left. After reacting in a 170 ° C oil bath for 7 hours,
As a result of analyzing the reaction solution by gas chromatography, the conversion rate of phenol was 4.3%, and methylphenyl carbonate (displayed as MPC) was 3.5 based on phenol.
Obtained in a yield of%. The selectivity was 80.8%.

Examples 2 to 8 The same operation as in Example 1 was carried out except that the type of catalyst was changed. The results are shown in Table 1.

[0029]

[Table 1]

Comparative Example 2 The procedure of Example 1 was repeated except that the catalyst La (OAc) ₃ used in the reference was used. The conversion of phenol was 10.1%, but MPC and diphenyl carbonate (indicated by DPC) which were the target reaction products were hardly formed.

Example 9 (Reaction from MPC to DPC) In the same reactor as in Example 1, 7.5 mmol (0.68 g) of dimethyl carbonate and 7.5 mm of phenol were added.
ol (0.71 g), 2.5 mmol of YbCl ₃
(0.70 g) was added, the mixture was heated in an oil bath at 170 ° C. under normal pressure, and heated and totally refluxed for 1.5 hours to pretreat the catalyst. Next, the pressure was reduced and the remaining DMC was distilled off to prepare a catalyst. After cooling to below 60 ° C, dimethyl carbonate 10
0 mmol (9.0 g), phenyl acetate 100 mmo
1 (13.6 g) was added, and the temperature was raised to 170 ° C. and heated again.
The top temperature of the distillation section is 80 ° C while controlling the temperature of the distillation section.
The reaction was carried out so that the amount of methanol produced by the reaction was distilled off.

After reacting at a reaction temperature of 170 ° C. for 5 hours and cooling, the reaction solution was analyzed by gas chromatography.
The conversion rate of phenyl acetate was 95.4%, and methyl phenyl carbonate (denoted as MPC) and diphenyl carbonate (denoted as DPC) were obtained in yields of 56.4% and 35.1%, respectively, based on phenyl acetate. Was given. The overall yield is 91.5% based on phenyl acetate. MPC and D
The selectivity of the entire PC was 96.8%. The calculation formulas for the conversion rate, the selectivity, and the yield were calculated by Equation 1, Equation 2, and Equation 3, respectively.

Example 10 The same reactor as in Example 1 was charged with dimethyl carbonate 2
5 mmol (2.25 g), phenol 50 mmol
(4.71 g), 2.5 mmol of YbCl ₃ (0.7
0 g), and heated in an oil bath at 170 ° C. under normal pressure,
The catalyst was pretreated by heating and total reflux for 5 hours. Next, the pressure was reduced and the remaining DMC was distilled off to prepare a catalyst.
After standing to cool to 60 ° C or lower, MPC 50 mmol (7.6 g)
Was added and heated again to 170 ° C., and while controlling the temperature of the distillation section, reactive distillation was carried out so that the column top temperature of the distillation section did not exceed 80 ° C., and methanol produced by the reaction was distilled off.

After reacting at 170 ° C. for 1 hour and cooling, the reaction solution was analyzed by gas chromatography.
The yield of DPC based on MPC was 59%. DP
The selectivity of C was 86%.

Comparative Example 3 The procedure of Example 1 was repeated, except that a known representative catalyst, Ti (OPh) _4, was used. The conversion rate of phenol is
It was 11.0%. MPC production was 11.0% yield based on phenol. The MPC selectivity was 100%.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Office reference number FI technical display location B01J 31/12 C07C 68/06 Z 9279-4H // C07B 61/00 300

Claims (1)

[Claims] 1. A method for producing an aromatic carbonic acid ester, which comprises transesterifying a carbonic acid dialkyl ester or an alkyl carbonic acid aryl ester with a phenol or its acyl ester in the presence of a compound of a rare earth element as a catalyst. The alkyl group of has 1 to 4 carbon atoms
Is a lower aliphatic group, and the aryl group is a phenyl group or a substituted phenyl group having 7 to 15 carbon atoms,
As a catalyst, rare earth elements Yb, Tm, Ho, Dy, Tb,
Using a compound of one or more elements selected from Sm, Nd and Pr, as a reaction pretreatment, 3 to 100 times mol of phenols and 1 to 20 times mol of dialkyl carbonate relative to the catalyst are used. 120 to 250 ° C. in the presence of esters and / or alkyl aryl carbonates
A carbonic acid alkylaryl ester and a carbonic acid diaryl carbonate produced by further carrying out a transesterification reaction by further adding a raw material of a carbonic acid dialkyl ester and / or a carbonic acid alkylaryl ester using the catalyst pretreated by heating Method for producing esters.