JPH07224008A - Production of aromatic carbonic acid estr - Google Patents

Abstract

PURPOSE:To provide a method for efficiently obtaining an aromatic carbonic acid ester by reacting phosgene or an aromatic-carbonic acid monoester chloride with an alkali metallic salt of an aromatic hydroxy compound. CONSTITUTION:This method for producing an aromatic carbonic acid ester is to use a reciprocation rotating type stirrer in reacting an aqueous solution of an alkali metallic salt of an aromatic hydroxy compound with phosgene or an aromatic carbonic acid monoester chloride in the presence of an organic solvent and producing the aromatic carbonic acid ester. Thereby, the aromatic carbonic acid ester can be obtained at a high rate of reaction in high yield by using the reciprocation rotating type stirrer.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for producing an aromatic carbonic acid ester. More specifically, the present invention uses a reciprocating rotary stirrer as a stirrer when an aromatic carbonic acid ester is produced by reacting phosgene or an aromatic carbonic acid monoester chloride with an alkali metal salt of an aromatic hydroxy compound. The present invention relates to a method for efficiently producing an aromatic carbonic acid ester. Aromatic carbonate is useful as a raw material for aromatic polycarbonate by the melt transesterification method.

[0002]

2. Description of the Related Art Conventionally, aromatic carbonates have been produced by reacting an aromatic hydroxy compound with phosgene. The most commonly used method at present is to react phosgene with an alkali metal salt of an aromatic hydroxy compound in a solution of a heterogeneous layer of water and dichloromethane. However, since dichloromethane has a low boiling point, it is difficult to handle, and there are some drawbacks such as a chlorine compound generated by decomposition of dichloromethane itself corrodes the apparatus and pollutes the environment.

On the other hand, as a method not using dichloromethane, a method using toluene is shown in British Patent No. 841654, but when toluene is used, dispersibility with water is poor unlike in the case of dichloromethane, It is described that the reaction rate is significantly slowed down. As a method of solving this, a method of stirring at a high speed of 8000 rpm,
Two examples of methods of adding a surfactant are described. In order to obtain a sufficient reaction rate, a high speed rotation of 8000 rpm is required, and in the method of adding a surfactant,
Although the reaction is fast, a large amount of a surfactant is added, which makes it difficult to separate the organic layer from the aqueous layer after the reaction, which is an insufficient industrial technique.

[0004]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention As described above, the method using dichloromethane has problems of corrosion of the equipment and environmental pollution. On the other hand, the method which has been examined up to now as a method not using dichloromethane has a reaction rate. However, the problems such as the need for a special reaction apparatus that is slow and requires high-speed stirring have not been solved, and the method using dichloromethane as a solvent has not been surpassed.

An object of the present invention is to provide a method for producing an aromatic carbonate ester at a high reaction rate and a high yield without using dichloromethane as a solvent.

[0006]

Means for Solving the Problems As a result of intensive studies to solve the above problems, the present inventors have found that a reciprocating rotary stirrer is used in the reaction to obtain a high yield and a high yield. It was found that it is possible to produce an aromatic carbonic acid ester with a good reaction rate, and the present invention has been completed.

That is, according to the present invention, an aqueous solution of an alkali metal salt of an aromatic hydroxy compound is reacted with phosgene or an aromatic carbonic acid monoester chloride in the presence of an organic solvent,
This is a method of using a reciprocating rotary stirrer as a stirrer when producing an aromatic carbonate ester.

The stirring device used in the present invention is not particularly limited as long as it is reciprocatingly rotated, such as the number of rotations, the angle of rotation and the shape of the blade, but the number of rotations is 100 to 1000 cp.
m, and a rotation angle of 50 to 180 degrees is usually used.

The aromatic hydroxy compound used in the present invention is one in which hydroxy is directly bonded to an aromatic ring, and examples thereof include phenol, cresol, xylenol, dimethylphenol, trimethylphenol, tetramethylphenol, ethylphenol, Alkylphenols such as propylphenol, benzylphenol, bisphenol A; arylphenols such as phenylphenol, biphenol; halogenated phenols such as chlorophenol, bromophenol, dichlorophenol, dibromophenol; methylchlorophenol, ethylchlorophenol, ethyl Alkyl- and halogen-substituted phenols such as chlorophenol, methyl bromophenol, ethyl bromophenol; anisole, pheno Phenol, include bound phenol alkyl or aryl group through a heteroatom, such as phenyl thiophenol, it contained these include also the respective isomers.

The aromatic carbonic acid monoester chloride used in the present invention is an ester of chloroformic acid and the above aromatic hydroxy compound.

Any ratio of water to the organic layer may be used, but it is usually in the range of 1:10 to 10: 1, more preferably in the range of 1: 5 to 5: 1. .

As the organic solvent in the present invention, any organic solvent which is immiscible with water can be used, but from the viewpoint of stability during the reaction and high solubility of the product, an aromatic hydrocarbon is preferable. Specifically, benzene, toluene, xylene, ethylbenzene, chlorobenzene, etc. can be mentioned.

In the present invention, a tertiary amine can be used as a catalyst. The addition amount is 0.01 to 2.0% by weight based on the aromatic hydroxy compound. Three
As the primary amine, those known per se are used.
Examples include triethylamine, tripropylamine, tributylamine, pyridine and the like.

The reaction temperature for carrying out the present invention is about -20 to 60 ° C., preferably about 0 to 40 ° C., in consideration of hydrolysis stability of raw materials, handling safety, reaction rate and the like.

There is no particular limitation on the shape of the reactor used, and a commonly used reactor is used, but a baffle plate or the like can be attached if necessary in order to enhance the dispersibility. is there.

In the case of the method of the present invention, the reaction solution immediately separates into an aqueous layer and an organic layer after the stirring is completed. Therefore, the organic layer is separated, washed with water, and then the organic layer is distilled to remove the solvent and the like. Thus, the desired diphenyl carbonate can be easily obtained.

[0017]

EXAMPLES The method of the present invention will be explained by the following examples, but the present invention is not limited to these examples.

Example 1 A stainless steel cylindrical container (200 mmφ × 200 mm, content 6 L) equipped with a stirrer, a dropping funnel and a thermometer,
Phenol 216.75g (2.30mol), sodium hydroxide 106.37
g (2.66 mol), hydrosulfite 0.09 g (0.50 mmol),
A solution of 0.50 g (4.94 mmol) of triethylamine and 1000 g of water was previously cooled to 15 ° C. or lower and then added, and a solution of 43.34 g of bibenzyl (internal standard) in 1300.20 g of toluene was added. Also add phenyl chloroformate 37 to the dropping funnel.
8.64 g (2.42 mol) was prepared.

The above reactor was placed in a water bath having a bath temperature of about 30 ° C., the liquid temperature was adjusted to 27-28 ° C., and phenyl chloroformate was required for 15 minutes from the dropping funnel while stirring with a reciprocating rotary stirring device. And dropped. The liquid temperature was maintained at 30 ± 1 ° C. during the dropping and the reaction. The stirring was temporarily stopped every 5 minutes from the end of the dropping, and about 0.5 ml of the separated toluene phase was sampled and diluted with 10 ml of acetone, and then diphenyl carbonate in the reaction mixture was analyzed by gas chromatography using an internal standard solution. Was quantified. The results are shown in Table-1.

The reciprocating rotary stirring device (manufactured by Shimazaki Seisakusho, trade name "Agitator SV") used in this embodiment has a rotation speed of 800 cpm, a rotation angle of 90 degrees, and two stirring blades with triangular blades (blade length 80 mm). Are paired with each other and intersect at 90 degrees, and the distance between the blades is 20 mm.

Comparative Example 1 A one-way rotary stirring was used as a stirring device and the number of rotations was 4
The same procedure as in Example 1 was performed except that the speed was set to 00 rpm. The rotation speed of the one-way rotary stirring was set to 400 rpm, which is half the rotation speed of the stirrer, because the rotation of the stirring shaft in one cycle of the stirrer was 1/2 rotation. The results are shown in Table-1. (Below margin)

[Table 1]

[0022]

According to the method of the present invention, by using a reciprocating rotary stirrer, the desired diphenyl carbonate can be obtained with high yield and high reaction rate.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Katsushige Hayashi 22 Wadai, Tsukuba City, Ibaraki Prefecture Mitsubishi Gas Chemical Co., Ltd.

Claims (2)

[Claims] 1. A reciprocating rotary type stirring device for producing an aromatic carbonate by reacting an aqueous solution of an alkali metal salt of an aromatic hydroxy compound with phosgene or an aromatic carbonate monoester chloride in the presence of an organic solvent. A method for producing an aromatic carbonic acid ester, which comprises using a stirrer. 2. The method according to claim 1, wherein the organic solvent is an aromatic hydrocarbon.