JPH047035A - Catalyst for ester-exchange reaction and preparation of aromatic carbonic acid diester using the catalyst - Google Patents

Abstract

PURPOSE:To obtain a highly selective and active catalyst for ester-exchange reaction which is useful for obtaining aromatic carbonic acid diester from alkylcarbonic acid diester and a phenolic compound by selecting from metal containing metallic aluminum, aluminum phenoxide, and aluminum methoxide. CONSTITUTION:A catalyst for ester-exchange reaction is obtained by selecting from a metal containing at least metallic aluminum, aluminum phenoxide, and aluminum methoxide. The metal containing metallic aluminum covers metal aluminum itself and aluminum alloys containing metallic aluminum. The state of the metal catalyst may be either flaky powders or granules. The aimed catalyst for ester-exchange reaction is used for ester-exchange reaction of alkylcarbonic acid diester or aryl-alkylcarbonic acid diester with a phenolic compound and an aromatic carbonic acid diester is obtained highly selectively.

Description

Detailed Description of the Invention [Industrial Field of Application] The present invention provides a transesterification catalyst useful for obtaining an aromatic carbonate diester by transesterification of an alkyl carbonate diester with a phenol compound, etc. The present invention relates to a method for producing the aromatic carbonic acid diester used.

[Prior Art and Problems to be Solved by the Invention] Aromatic carbonic acid diesters are used as raw materials for synthetic resins such as polycarbonate and isocyanate-1 compounds. This aromatic carbonic acid diester is obtained by a transesterification reaction between an alkyl carbonic diester and a phenol compound. Various catalyst systems have been proposed for the transesterification catalyst used in this reaction. For example, JP-A-56-123948 discloses Ti-based and AI-based catalysts, and JP-A-56-40708 proposes trialkylsus compounds.

However, all of these catalysts have insufficient catalytic activity and selectivity, and are likely to be accompanied by side reactions. Therefore, in the transesterification reaction using the above catalyst, side reactants such as dialkyl ether, diaryl ether, and alkylaryl ether are likely to be produced, resulting in a decrease in the yield of aromatic carbonic acid diester.

Therefore, an object of the present invention is to achieve high catalytic activity and selectivity in a transesterification reaction in which an alkyl carbonate diester or an aryl-alkyl carbonate diester is transesterified with a phenol compound or its acyl ester.
It is an object of the present invention to provide a catalyst for transesterification reaction which can obtain aromatic carbonic acid diesters in good yield.

Another object of the present invention is to provide a manufacturing method that can efficiently obtain an aromatic carbonic acid diester.

[Structure of the Invention] To achieve the above object, the present invention provides a catalyst for transesterification selected from a metal containing at least metallic aluminum, aluminum phenoxide, and aluminum methoxide.

The present invention also provides a method for producing an aromatic diester carbonate, in which the transesterification reaction between an alkyl diester carbonate or an aryl-alkyl diester carbonate and a phenol compound or an acyl ester thereof is carried out in the presence of the above catalyst for transesterification reaction. do.

In the catalyst for transesterification of the present invention, the metal containing at least metallic aluminum includes a single metallic aluminum and an aluminum alloy containing metallic aluminum. Further, the aluminum alloy is not particularly limited as long as it is an alloy containing metal aluminum, for example, CuS
Zn, Ni, Fe, Co, Sn, Cr, Mn, Mo
, Mg, and at least one metal.

Although the proportion of aluminum alloy is not particularly limited and can be selected within a wide range, the aluminum content is usually about 5 to 95% by weight, preferably about 25 to 75% by weight. The metal catalyst may be in the form of foil powder, granules, blocks, lines, or rods, and exhibits high catalytic activity regardless of its form.

Further, the catalyst for transesterification of the present invention includes aluminum phenoxide and aluminum methoxide. These compounds also exhibit high catalytic activity.

At least one of these catalysts for transesterification may be used.

The transesterification catalyst of the present invention is suitably used in the reaction of transesterifying an alkyl carbonate diester or an aryl-alkyl carbonate diester with a phenol compound or its acyl ester to obtain an aromatic carbonate diester.

The aromatic diester carbonate represented by the general formula [m] is an alkyl carbonate diester or an aryl-alkyl carbonate diester represented by the general formula CI], and a phenol compound represented by the general formula [11] or its acyl ester. Obtained by transesterification reaction of

[I] [■Ko> (A r O) 2 C= 0 [m] (wherein, R1 and R2 are the same or different and have a carbon number of 1
〜]0 represents an alkyl group or an aryl group which may have a substituent. Ar represents an aryl group which may have a substituent. R3 represents a hydrogen atom or an acyl group. However, R1 and R2 are not aryl groups which may have a substituent at the same time. ) The alkyl group of the compound represented by the general formula [1] is, for example, a linear or Examples include branched alkyl groups.

The alkyl groups R1 and R2 may be different from each other.

Among these alkyl groups, alkyl groups having 1 to 4 carbon atoms, particularly methyl groups, are preferred.

Examples of the aryl group include phenyl, naphthyl, and anthryl groups. Examples of substituents include chlorine,
Bromine, iodine, etc. l\rogen atoms: methyl, ethyl,
Alkyl groups such as propyl, isopropyl, butyl groups;
Cycloalkyl group such as cyclohexyl group; methoxy,
Alkoxy groups such as ethoxy, propoxy, isopropoquine, and fudoquin; cycloalkyloxy groups such as cyclohexyloxyne; aryloxy groups such as phenoxy and naphthoxy; aralkyl groups such as benzyl and phenethyl; nitro groups; Basic examples include. One or more of these substituents may be substituted at any position of the aryl group.

Examples of the compound represented by the general formula [I] include:
Dimethyl carbonate, diethyl carbonate, dipropyl carbonate, diisopropyl carbonate, dibutyl carbonate, cyhequin carbonate, dioctyl carbonate, methyl phenyl carbonate diester, ethyl carbonate
Examples include phenyl carbonate diester, propyl-phenyl carbonate diester, isopropyl-phenyl carbonate diester, butyl-phenyl carbonate diester. Among these compounds, a particularly preferred compound is dimethyl carbonate.

In the compound represented by the general formula [11], examples of the aryl group which may have a substituent include the same groups as mentioned above. Examples of the acyl group include acyl groups corresponding to the alkyl groups described above. Among the compounds represented by the general formula [■], a preferred compound is phenol.

The production method of the present invention is preferably applied to the transesterification reaction between an alkyl carbonate diester and a phenol compound, which is industrially easy and advantageous.

It is possible to change the ratio of the compound represented by the general formula [1] and the compound represented by the general formula [11] in an arbitrary ratio, and preferably the molar ratio is about 1:2 to 1:10. It is.

In the transesterification reaction, the catalyst for the transesterification reaction can be used in a wide range that does not hinder the progress of the reaction. The amount of catalyst is usually 0.001 to 1, based on the total reaction mixture.
．． 0 mol/fl, preferably 0.01-0.1 mol/g
That's about it.

The transesterification reaction between the compound represented by the general formula [1] and the compound represented by the general formula [11] is usually an equilibrium reaction. Therefore, in order to allow the reaction to proceed smoothly, it is preferable to remove part of the product, for example, the alcohol produced, continuously or intermittently before the reaction. The reaction temperature can be determined depending on the type and composition of the compound represented by the general formula [I] and the compound represented by the general formula [n], the reaction pressure, etc., and is usually 50 to 200°C, preferably is 70-1
The temperature is about 50°C.

The aromatic carbonic acid diester obtained by the transesterification reaction can be isolated by a conventional separation and purification method.

[Effects of the Invention] The catalyst for transesterification of the present invention has high catalytic activity and selectivity, and can obtain aromatic carbonic acid diesters in good yield.

Further, the method for producing an aromatic carbonate diester of the present invention suppresses side reactions and can efficiently produce an aromatic carbonate diester.

[Examples] The present invention will be explained in more detail based on Examples below.

Example 1 Phenol 244.7mM, dimethyl carbonate 55°6m
M, 0.14 g of aluminum foil (5.5 mg atoms as aluminum), and 30 g of Hensen were placed in a 200 ml Mitsulo reaction flask, and a 50 ml Soxhlet extractor filled with 40 g of molecular sieves 4A was connected to the top of the flask.

Further, a condenser was provided above the extractor, and the reaction solution was heated under reflux at a temperature of 85 to 90° C. for 8 hours.

As a result of gas chromatography analysis of the reaction solution, it was determined that it was methylphenyl carbonate based on dimethyl carbonate.
A yield of 36.5 mol 96% of diphenyl carbonate was produced with a trace amount of anisole of less than 0.1 mol %.

Comparative Example 1 The same reaction as in Example 1 was carried out except that 55 mM of di-n-butylsulfur oxide was used as a catalyst.

When the reaction solution was analyzed by gas chromatography after heating was stopped, methylphenyl carbonate was found to be 38.1 mol%.
, diphenyl carbonate was produced in a yield of 10.5 mol%. On the other hand, 0.5 mol% or more of side reaction products such as anisole were produced. The amount of this side reaction product is about 5 times or more compared to Example 1.

Comparative Example 2 A reaction similar to Example 1 was carried out except that 5.5 mM of tetrabutoxy titanate was used as a catalyst.

When the reaction solution after heating was stopped was analyzed by gas chromatography, methylphenyl carbonate was found to be 50.5 mol%.
, diphenyl carbonate was produced in a yield of 7.6 mol%. Furthermore, the reaction solution was colored deep red, which was not observed in Example 1 or Comparative Example 1.

Comparative Example 3 Triisopropoxyaluminate 5°5mM as catalyst
The same reaction as in Example 1 was carried out except that .

When the reaction solution after heating was stopped was analyzed by gas chromatography, methylphenyl carbonate was produced in a yield of 50.0 mol% and diphenyl carbonate was produced in a yield of 10.0 mol%. In this comparative example, although the same type of aluminum catalyst was used, the conversion rate of methylphenyl carbonate to diphenyl phonate was low, about 1/4 of that of Example 1. In addition, trace amounts of by-products produced in conjunction with isopropyl alcohol from the catalyst, such as methyl isopropyl carbonate, isopropylphenyl carbonate, and methyl isopropyl ether, were also detected.

Example 2 Phenol 244.7mM, dimethyl carbonate 556mM
M, 0.14 g of aluminum powder (5.5 mg atoms as aluminum), and 30 g of benzene were placed in a 200 ml Mitsuro reaction flask, and heated under reflux for 8 hours in the same manner as in Example].

Analysis of the reaction solution by gas chromatography revealed that it was methylphenyl carbonate based on dimethyl carbonate.
Diphenyl carbonate was produced in a yield of 30.3 mol%, and trace amounts of anisole were less than 0.1 mol%.

Example 3 Phenol 244.7mM, dimethyl carbonate 55°6m
M, nickel-aluminum Raney alloy 0°4g
(11.8 mg atoms as aluminum), benzene 3
0 g was placed in a 200 ml Mitsuro reaction flask, and heated under reflux for 8 hours in the same manner as in Example 1.

As a result of analyzing the reaction solution by gas chromatography, the amount of methylphenyl carbonate was 42% based on dimethyl carbonate.
The yield of diphenyl carbonate was 19.7 mol%, and the trace amount of anisole was less than 0.1 mol%.

Example 4 Phenol 244.7 mM, dimethyl carbonate 55°6 mM, aluminum-copper-zinc alloy (composition ratio A
l: Cu: Zn-50; 45: 5) 0.5
g (9.8 mg atoms as aluminum), benzene 3
0 g was placed in a 200 ml Mitsuro reaction flask, and heated under reflux for 8 hours in the same manner as in Example 1.

Analysis of the reaction solution by gas chromatography revealed that it was methylphenyl carbonate based on dimethyl carbonate.
5 mol 96, diphenyl carbonate was produced in a yield of 17.2 mol %, and anisole was present in trace amounts of less than 0.1 mol %.

Example 5 Phenol 244.7mM, dimethyl carbonate 556mM,
Aluminum triphenoxide powder 2.0g (6
.

Analysis of the reaction solution by gas chromatography revealed that methylphenyl carbonate was 39% based on methyl carbonate.
Cyphenyl carbonate was produced in a yield of 34.6 mol%, and anisole was present in a trace amount of less than 0.1 mol%.

Claims (1)

[Scope of Claims] 1. A catalyst for transesterification selected from a metal containing at least metallic aluminum, aluminum phenoxide, and aluminum methoxide. 2. A method for producing an aromatic diester carbonate, comprising transesterifying an alkyl carbonic diester or an aryl-alkyl carbonic diester with a phenol compound or its acyl ester in the presence of the transesterification catalyst according to claim 1.