JPH05117189A - Production of bisphenol a - Google Patents

Abstract

PURPOSE:To obtain the subject compound useful as a raw material for epoxy resin and polycarbonate resin in high purity by removing crystal of the adduct of bisphenol A and phenol from the reactional product of phenol and acetone and recycling the remaining mother liquor to the reactional system. CONSTITUTION:Phenol is made to react with acetone in the presence of an acidic catalyst. The acidic catalyst and then the crystal of the adduct of bisphenol A and phenol are removed from the obtained reactional product and bisphenol is recovered from the adduct crystal. The remaining mother liquor is subjected to catalytic hydrogenation treatment and recycled to the main process to obtain the objective colorless high-purity bisphenol A.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a process for producing 2,2-bis (4-hydroxyphenyl) propane known as bisphenol A. Bisphenol A is a compound useful as a raw material for epoxy resins and polycarbonate resins, and its use and demand have increased in recent years. In order to obtain a high quality resin, colorless and highly pure bisphenol A is required.

[0002]

2. Description of the Related Art Bisphenol A is usually produced by reacting phenol and acetone in the presence of an acidic catalyst. In addition to bisphenol A, the reaction product contains unreacted phenol, unreacted acetone, a catalyst, reaction product water, and reaction by-products such as coloring substances. Hydrochloric acid and a strongly acidic cation exchange resin are typical examples of the acidic catalyst. Further, a sulfur-containing compound may be used as a cocatalyst (Japanese Patent Publication No. 45-10337).
46-19953).

Highly pure bisphenol A from the reaction product
As one of the methods for recovering, a catalyst from the reaction product,
After removing the reaction product water and a part of unreacted phenol by distillation or the like, the remaining liquid mixture is cooled to crystallize bisphenol A as an adduct having a molar ratio of 1: 2 with phenol. After separating the adduct from the mother liquor containing the reaction by-product, phenol is removed to recover bisphenol A. In the mother liquor from which the adduct has been separated, a large amount of bisphenol A remains in addition to unreacted raw materials and reaction by-products, so that this mother liquor can be recycled to the reaction system.

However, the reaction by-products such as dianine compounds, polyphenols, and coloring substances such as isopropenylphenol and the like react with the raw material phenol and acetone when they are circulated as they are, and become high molecular weight to be accumulated in the system, thus adducts and However, there is a problem that the purity and the hue of the product are deteriorated. Therefore, it is necessary to remove the coloring component when the mother liquor is recycled to the reaction system. Conventionally, in order to remove the coloring components when the mother liquor is recirculated, a decolorization method by adsorption using an acidic cation exchange resin is known. There is a problem in that the cation exchange resin must be periodically washed to remove the colored component (JP-B-55-34779).

On the other hand, as a method for improving the hue (decoloring) by hydrogenation treatment, ethylene glycols (Japanese Patent Laid-Open Publication No.
0-178834), glycerins (JP-A-61-61)
No. 166832) has been reported. As a method for hydrogenating a compound having an aromatic ring, JP-B-57-
Japanese Patent No. 40811 has been reported, but this method is to obtain a cycloalkyl by reducing an aromatic ring.

[0006]

SUMMARY OF THE INVENTION The object of the present invention is to provide a method for producing bisphenol A which can reduce the above-mentioned drawbacks in producing bisphenol A, that is, the content of coloring substances in the mother liquor. Especially. Another object of the present invention is to increase the amount of a coloring substance such as isopropenylphenol in the system when the mother liquor is circulated as it is, and further to accumulate and accumulate the coloring component by continuing the recirculation of the mother liquor, and thus the crystals and It is to reduce deterioration of the purity and hue of the product.

[0007]

According to the present invention, phenol and acetone are reacted in the presence of an acidic catalyst to remove the acidic catalyst and then the adduct crystals of bisphenol A and phenol from the resulting reaction product. Then, bisphenol is recovered from the adduct crystals, and the remaining mother liquor is subjected to catalytic hydrogenation treatment and then recycled to the main step, which is a method for producing bisphenol A.

(Main Step) The raw material phenol and acetone are reacted stoichiometrically in excess of phenol. The molar ratio of phenol and acetone is phenol / acetone = 3.
The range is -30, preferably 5-20. The reaction temperature is usually 30 to 100 ° C., preferably 50 to 80.
° C., the reaction pressure is usually carried out at a gauge pressure of atmospheric pressure ~5kg / cm ^2. As the acidic catalyst, a soluble acid such as hydrochloric acid or an insoluble acid such as a strongly acidic cation exchange resin is used. Furthermore, in order to achieve a practical reaction rate, phenol-soluble mercaptans, for example,
It is also possible to add a lower alkyl mercaptan such as methyl mercaptan or ethyl mercaptan, or a cocatalyst such as thioglycolic acid to the reaction system to increase the reaction rate.

When a soluble acidic catalyst such as hydrochloric acid is used, the reaction product flowing out from the reaction zone is subjected to vacuum distillation, as is well known, to remove hydrochloric acid, unreacted acetone, reaction product water and a small amount of phenol. It becomes a liquid mixture of phenol and bisphenol A. The conditions of vacuum distillation are preferably such that the pressure is 50 to 300 mmHg and the temperature is 70 to 130 ° C. Similarly, when a strongly acidic cation exchange resin is used, unreacted acetone, reaction product water and a small amount of phenol are removed by distillation under reduced pressure to form a liquid mixture. Next, this liquid mixture is cooled to crystallize an adduct of bisphenol A and phenol, and after separating this crystal, phenol in the adduct crystal is removed by a method such as vacuum distillation to recover bisphenol A. To be done.

(Mother liquor treatment) The solution (mother liquor) in which most of bisphenol A has been separated and removed in advance as adduct crystals of bisphenol A and phenol from the reaction product contains not only bisphenol A but also many impurities. I'm out. However, since a large amount of bisphenol A is still present in this mother liquor in addition to unreacted raw materials and reaction by-products, it is preferable to recycle this mother liquor to the reaction system for reuse. However, as described above, a reaction by-product, such as a dianine compound, a coloring substance such as polyphenol and isopropenylphenol, further reacts with the raw material phenol or acetone when circulated as it is, accumulates in the system to have a high molecular weight, Although there is a problem of deteriorating the crystallinity and product purity and hue, the problem can be solved by catalytically hydrogenating the whole amount or a part of the mother liquor in the present invention.

The hydrogenation catalyst used in the catalytic hydrogenation reaction of the mother liquor is usually a carbonyl compound, a carbon-carbon unsaturated compound, an imide or the like having the ability to hydrogenate a so-called double bond to form a single bond. Can be mentioned. However, it is necessary to use the hydrogenation catalyst under conditions where the target product, such as bisphenol A, is not nuclear hydrogenated. A typical example of the catalyst is a nickel catalyst,
Examples thereof include a cobalt catalyst, a copper-chromium catalyst, a platinum group catalyst such as a palladium catalyst, a rhodium catalyst, and a platinum catalyst. These metal catalysts are suitable supports such as aluminum oxide,
Those supported on silicon oxide, pumice, pentonite or magnesium silicate are preferred. A development catalyst such as Raney nickel or Raney cobalt can also be used.

In the hydrogenation treatment of the present invention, the treatment temperature is not particularly limited, but it is generally in the range of 40 to 150 ° C, preferably 50 to 100 ° C. The processing pressure is usually a gauge pressure of 5 to 10 kg / cm ² . As for the reaction system, in consideration of industrial embodiments such as separation of the reaction product and the catalyst, a fixed bed type reaction with a molded catalyst is generally preferred, and the supply rate of the treatment liquid is a liquid space velocity (LH).
A range in which the SV) is 0.1 to 10 hr ^-1 is suitable. When a batch reaction is carried out, it generally depends on the mother liquor, although it varies depending on the reaction temperature, the reaction pressure and the like.
A catalyst amount of 5-10% by weight is suitable. Further, the hydrogen reduction of the present invention is also carried out by a compound such as lithium aluminum hydride, sodium aluminum hydride, potassium borohydride, calcium borohydride, zinc borohydride which decomposes or reacts with water to generate hydrogen. It can be carried out.

In the mother liquor treated by the above method, unreacted hydrogen is separated by a gas-liquid separator or the like, if necessary, and then recycled by the following method, and high-purity bisphenol A is added according to a usual method. Can be recovered. First, the liquid to be treated is cooled, bisphenol A is further crystallized from an adduct with phenol, and collected as crystals (second crystal). The crystals are supplied to the main crystallization step, and the mother liquor is collected. It can be recycled to the main reaction system (JP-A-2-833).
No. 83). Secondly, the liquid to be treated is decomposed in the presence of a basic catalyst according to a usual method (Japanese Patent Publication No. 49-48319, etc.) to obtain p-isopropenylphenol and phenol which are decomposition products. The decomposition products can be recombined in the presence of an acidic catalyst to give bisphenol A and then recycled to the main reaction system. Thirdly, the liquid to be treated is treated with an acidic cation exchange resin or a mineral acid such as hydrochloric acid,
After isomerization of by-products such as 2- (2-hydroxyphenyl) -2- (4-hydroxyphenyl) propane (Japanese Patent Publication No. 49-48319), it can be recycled to the main reaction system. .. Furthermore, the process according to the invention is
It can be recycled to the main reaction system after the above-mentioned recombination treatment or after the isomerization treatment with the above-mentioned acidic catalyst. The desired high-purity colorless bisphenol A can be obtained by a usual method through these methods.

[0014]

According to the method of the present invention, the content of the coloring matter in the mother liquor recycle stream can be reduced and the accumulation thereof can be prevented, so that colorless and high quality bisphenol A can be obtained as a product.

[0015]

EXAMPLES Hereinafter, the method of the present invention will be specifically described with reference to Examples. Example 1 A reaction tube with a jacket was prepared by partially neutralizing Amberlyst-31 (manufactured by Rohm and Haas) which is a sulfonic acid type ion exchange resin with mercaptoethylamine.
cc filled. A mixture of phenol and acetone (phenol / acetone = 10 mol / 1 mol) was continuously oiled for 100 hours at a liquid space velocity of 1 hr ⁻¹ while maintaining the temperature of the catalyst layer at 70 ° C. The reaction product liquid extracted from the reactor was measured for absorbance at 420 nm with a spectrophotometer and converted into APHA. APHA was 50, and 2000 g of the unreacted acetone, reaction product water, and reaction By-products and small amounts of phenol were removed. This concentrated solution was cooled to 45 ° C. and then centrifuged with a centrifuge to give 367 g of adduct crystals (recovery rate 60%) and mother liquor 9
It was separated into 81 g. By distilling the obtained adduct crystals under reduced pressure, 256 g of bisphenol A was obtained.

On the other hand, the mother liquor APHA is 114,
120 g of this mother liquor and ₂ g of platinum-Al ₂ O ₃ catalyst are 300 m
The autoclave was charged into the autoclave, the air in the autoclave was replaced with hydrogen, and the mixture was stirred at 500 rpm and the reaction temperature was adjusted to 6
The treatment was carried out at 0 to 65 ° C. for 2 hours while maintaining the hydrogen pressure at 7 kg / cm ² -G. The APHA of this treatment liquid is 75,
The hue was improved. 0.1 g of NaO was added to this treatment liquid.
After H was added, reactive distillation was performed at 200 ° C. under reduced pressure of 200 mmHg to obtain 96 g of a mixture of phenol and p-isopropenylphenol from the top of the column. Amberlyst 31 was added to this mixture, and the mixture was stirred at 70 ° C. to carry out the recombination reaction,
The catalyst was separated to obtain 95 g of the recombined liquid. This recombined solution was mixed with 195 g of the reaction product solution, and vacuum distillation (concentration), crystallization and separation were carried out in the same manner as described above. As a result, the adduct crystals and mother liquor obtained at the first time had the same purity and hue. Got things. The recovery rate of adduct crystals was 60%.

Example 2 As a hydrogenation catalyst, catalytic hydrogenation treatment was carried out in the same manner as in Example 1 except that Raney nickel was used instead of platinum-Al ₂ O ₃ to obtain a treated solution of APHA 91. ..

Example 3 940 g of phenol and 73 g of acetone were mixed, and the reaction was carried out at 55 ° C. for 9 hours while blowing hydrogen chloride gas. The reaction liquid extracted from the reactor was used in Example 1
The same treatment as in (1) was performed to obtain a mother liquor. This mother liquor (APHA
When 121) was subjected to the catalytic hydrogenation treatment in the same manner as in Example 1, a treated solution of APHA 61 was obtained.

Claims (1)

[Claims] 1. Phenol and acetone are reacted in the presence of an acidic catalyst, and the reaction product obtained is used to obtain the acidic catalyst,
Next, crystals of the adduct of bisphenol A and phenol are removed, bisphenol is recovered from the crystals of adduct, and the remaining mother liquor is subjected to catalytic hydrogenation treatment and then recycled to the main step. Method.