JPH10279511A - Production of bisphenol a - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a high-purity bisphenol compound, capable of removing impurities derived from a trace of an acid and an acid catalyst, suppressing decomposition and discoloration resulting from an acid and reducing corrosion of an apparatus. SOLUTION: Phenol is reacted with acetone in the presence of an acidic catalyst, the acidic catalyst is removed from the prepared crude product to give a reaction mixture. At least a part of the reaction mixture is brought into contact with a solid zinc compound. An adduct of phenol to bisphenol A is separated from the reaction mixture prepared by removing the catalyst from the obtained crude product to give a mother liquor, at least a part of the mother liquor is brought into contact with the solid zinc compound and recycled to a reaction system to produce bisphenol A.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a method for producing bisphenol A. Bisphenol A is useful as a raw material for polycarbonate resins and epoxy resins useful as engineering plastics, and its demand is increasing. For these uses, colorless and highly pure bisphenol A is required.

[0002]

2. Description of the Related Art A bisphenol compound is obtained by reacting a phenol compound with a carbonyl compound in the presence of an acid catalyst. Representative examples of the acid catalyst include an inorganic acid such as hydrochloric acid and a cation exchange resin. Further, a sulfur compound may be used as a promoter. The reaction product contains by-products such as an unreacted phenol compound, an unreacted carbonyl compound, produced water, a catalyst, and a coloring substance in addition to the bisphenol compound. As a method of obtaining a bisphenol compound having high purity from the reaction product, for example, when a soluble acid catalyst such as hydrochloric acid is used, unreacted acetone is generally obtained from the reaction product by distillation under reduced pressure,
It is removed together with the generated water. However, distillation leaves a trace amount of an acidic substance (acid catalyst), which causes problems such as corrosion of the apparatus, decomposition of products in a later step, and deterioration of hue. In the case of using a cation exchange resin, the removal of the catalyst is easier than in the case of using a soluble acid. The same problem as in the case of using.

[0003] As a method for removing the residual acid catalyst in the reaction product, Japanese Patent Publication No. 5-44,932 discloses a method in which a mixture obtained by removing an acid catalyst from a reaction product is converted into a weak base having a pyridyl group as an exchange group. A method for contacting with a ionic ion exchange resin is disclosed. JP-A-5-201,905 discloses that a mother liquor obtained during crystallization of a 1: 1 adduct of phenol and bisphenol A is isomerized and then reacted with a basic ion-exchange resin to obtain an acidic solution. A method for removing impurities is disclosed. JP-A-1-156,937 discloses a method of contacting a crude bisphenol A product or a mother liquor obtained during crystallization of a 1: 1 adduct of phenol and bisphenol A with a basic anion exchange resin. Is disclosed. Also, Japanese Patent Publication No. 57-14,329 discloses that
A method is disclosed for separating an acidic agent from the reaction product and contacting it with a material selected from the group consisting of activated carbon and activated earth. JP-A-4-117,341 discloses a method in which a mixture obtained by removing an acidic catalyst from a reaction product or a mother liquor obtained during crystallization of a 1: 1 adduct of phenol and bisphenol A is brought into contact with a solid magnesium compound. Is disclosed.

However, in the method of removing the residual acid catalyst using an anion exchange resin, exchange groups are eliminated similarly to the case where a cation exchange resin is used as a catalyst for the reaction, which causes a new contamination. Become. In addition, when an adsorbent such as activated carbon is used, there is a problem that its removal ability is low.In addition, when a solid magnesium compound is used, a complex oxide having a high removal efficiency has a problem in the oxide. There is a problem that components are mixed into the system and cause new contamination.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to suppress the decomposition and coloring of bisphenol A caused by an acid and to reduce equipment corrosion by removing trace acids and impurities derived from an acid catalyst. Another object of the present invention is to provide a method for producing a high-purity bisphenol compound.

[0006]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention solves the above problem by solidifying at least a part of a reaction product obtained by removing an acidic catalyst from a reaction mixture or a mother liquor obtained by separating an adduct of phenol and bisphenol A. The present inventors have found that the object of the present invention can be achieved by contacting with a zinc compound and efficiently removing trace acids and impurities caused by the acid, thereby completing the present invention. That is, the gist of the present invention is that a phenol and acetone are reacted in the presence of an acidic catalyst, and a reaction product obtained by removing an acid catalyst from the obtained crude product, or
This is a method for producing bisphenol A, which comprises contacting a residual acidic substance in a recycle stream with a solid zinc compound.

[0007]

DETAILED DESCRIPTION OF THE INVENTION Bisphenol A is prepared by dehydrating and condensing 2 mol of a phenol compound and 1 mol of a carbonyl compound in the presence of acetone and a stoichiometric excess of phenol, generally in the presence of an acid catalyst. can get.
In this reaction, the molar ratio of phenol to acetone is usually 4 to
12 and a reaction temperature of 0 to 120 ° C., preferably 40 ° C.
It is performed in the range of 100 ° C. The reaction pressure is usually from normal pressure to 5 kg / cm ² . As the acid catalyst, a soluble acid such as hydrochloric acid or an insoluble acid such as a strongly acidic ion exchange resin is used.

When a soluble acid is used as a catalyst,
The reaction product is heated to a temperature of about 110 ° C. to 120 ° C. under reduced pressure to remove the catalyst, product water, and phenol, and then separated from the mother liquor by centrifugation as an adduct of bisphenol A and phenol. Bisphenol A can be obtained by thermal decomposition to A. Since the mother liquor from which the adduct of phenol and bisphenol A has been removed contains unreacted raw materials and bisphenol A, this mother liquor is recycled into the reaction system. When an insoluble acid such as an ion exchange resin is used, unreacted phenol and generated water are removed by vacuum distillation after separating the catalyst, and bisphenol A is obtained in the same manner as when a soluble acid is used as the catalyst. Can be.

The solid zinc compound in the present invention includes:
Zinc oxides, hydroxides, carbonates, sulfates, phosphates, complex oxides, complex salts and the like can be mentioned. Specifically, Zn
O, Zn (OH) ₂ , ZnCO ₃ , ZnSO ₄ , Zn ₃
(PO ₄ ) ₂ , ZnP ₂ , Zn (ClO ₄ ) ₂ , ZnS
e, ZnS, ZnTe, ZnTiO ₃ , ZnWO ₄ , Z
nCl ₂ , ZnBr ₂ , 3Zn (OH) ₂ .2ZnCO
₃ , CaO-ZnO and the like. These zinc compounds may be used alone or as a mixture of two or more. Further, the zinc compound may be supported on a carrier such as silica, alumina, activated carbon, or the like, or may be used as a mixture. Such a zinc compound has a wide usable temperature range and does not elute impurities into the reaction system.

The contact method may be a continuous method or a batch method.
The processing temperature is generally about 40 to 200 ° C, preferably 40 to 180 ° C. Although it depends on the type of zinc compound used, the amount of the zinc compound is about 0.01 to 20% by weight, preferably 0.1 to 10% by weight, based on the amount of the processing solution in the case of a batch type. The contact time is 0.
It is about 05 to 10 hours, preferably about 0.1 to 5 hours. In the continuous method, SV is 0.01 to 30 hr ^-1 ,
Preferably it is about 0.05 to 20 hr ^-1 .

In the method of the present invention, removal of trace amounts of acid and impurities caused by acid by contact with a solid zinc compound can be carried out by the following method. That is, [1] acetone and excess phenol are reacted in the presence of an acidic catalyst to obtain crude bisphenol A, the catalyst is removed from the reaction solution, and unreacted phenol, acetone, impurities and the like are removed by distillation. At least a part of the reaction solution is brought into contact with a solid zinc compound to remove residual acidic components. Alternatively, the treatment with the solid zinc compound can be performed before the distillation step of phenol or the like.

After the treatment with the solid zinc compound, high-purity BPA can be obtained by a known method. For example, a method of recovering bisphenol A by cooling the liquid to be treated to crystallize bisphenol A as an adduct with phenol, separating the crystals and removing phenol from the adduct, or A method can be used in which phenol is removed from the treatment liquid, and then bisphenol A is distilled and recrystallized with a solvent.

Alternatively, [2] when bisphenol A is isolated by crystallization after the catalyst removal step and the phenol distillation step, bisphenol A or an adduct of phenol and bisphenol A is separated by filtration or centrifugation. After the resulting mother liquor is brought into contact with the solid zinc compound, it can be recycled to the reaction system. As described above, in the method of contacting with the solid zinc compound of the present invention,
Since no impurities are eluted in the reaction system, the mother liquor can be effectively recycled.

[0014]

EXAMPLES The method of the present invention will be specifically described below with reference to examples. Unless otherwise specified, the concentration in% in the examples is the concentration by weight. Example 1 850 g of phenol and 87 g of acetone were condensed in the presence of a hydrochloric acid catalyst, and the crude product was dried at 70 mmHg and 120 ° C.
To remove hydrochloric acid, product water, unreacted acetone, and unreacted phenol. The composition of the obtained liquid was as follows. Phenol 64% Bisphenol A 34% o, p 'isomer 0.5% Other by-products 1.5% 2% zinc oxide powder was added to the bisphenol A crude reaction solution having the above composition at 125 ° C. The mixture was stirred for 5 hours.
After filtering the zinc oxide, the iron content was analyzed by a colorimetric method, and the chlorine content was analyzed by a potentiometric titration method (precipitation titration method).
As a result, both the iron content and the acid content were reduced and the hue was improved as compared to before the treatment. Table 1 shows the results. Next, phenol was removed from the treated solution by distillation, and water was added to cool the solution to obtain an adduct of phenol and bisphenol A. Further distillation was performed to obtain bisphenol A, but decomposition of the product did not occur, and bisphenol A having a good melt color was obtained.

Example 2 The same operation as in Example 1 was performed except that the solid zinc compound was changed from zinc oxide to zinc sulfide. Table 1 shows the results.

Example 3 The addition amount of zinc oxide was 1 wt% with respect to the crude reaction solution of Example 1.
%, And the same operation and analysis as in Example 1 were performed. Table 1 shows the results. Comparative Example 1 The same operation as in Example 1 was performed except that the solid zinc compound was not added. Table 1 shows the results.

[0017]

[Table 1]

EXAMPLE 4 100 ml of zinc oxide pellets (3/16 ") are packed in a jacketed packed bed (27 m.times.30 cm) and the mixture of Example 1 at 125 DEG C., SV = 6.6-14. .8h
The liquid was passed under the condition of r ⁻¹ , and the impurity concentration before and after the treatment was measured 5 hours later. Table 2 shows the results.

[0019]

[Table 2]

Example 5 A mixed solution having a phenol / acetone molar ratio of 10 was added to a stationary reactor filled with a sulfonic acid type ion exchange resin partially neutralized with mercaptoethylamine at 70 ° C.
V. Was passed through so as to be 2 hr ^-1 to continuously carry out a reaction. The crude product was distilled under reduced pressure to remove generated water, unreacted acetone, and unreacted phenol. When the obtained liquid was subjected to the same operation as in Example 1 and the treatment liquid was analyzed by the same method, neither the acid component nor the iron component was detected in this liquid. Next, phenol was removed from the treated solution by distillation, and water was added to cool the solution to obtain an adduct of phenol and bisphenol A. Further distillation was performed to obtain bisphenol A, but decomposition by impurities did not occur, and bisphenol A having a good melting color was obtained.

Example 6 The crude product stream obtained in Example 1 was added with water without contact with the solid zinc compound and then cooled to precipitate crystals of an adduct of bisphenol A and phenol, which were separated by filtration. A mother liquor having the following composition was recovered. Phenol 75% bisphenol A 22% o, p 'isomer 1.1% other by-products 1.9% 2% zinc oxide powder was added to this mother liquor,
h. After filtering the solid zinc compound, the results of analysis of iron and acid content are shown in Table 3. ,

[0022]

[Table 3]

Example 7 The crude product obtained in Example 5 was subjected to distillation under reduced pressure to remove produced water, unreacted acetone and unreacted phenol. After adding water thereto, the mixture was cooled to precipitate crystals of an adduct of bisphenol A and phenol, separated by filtration and the mother liquor was recovered. 2% zinc oxide powder was added to the mother liquor, and the mixture was stirred at 125 ° C. for 5 hours. After filtration of the catalyst, iron and acid content were analyzed, but none were detected.

[0024]

According to the present invention, since the present invention has the above-described structure, it is possible to prevent the decomposition of the bisphenol compound during high-temperature treatment such as distillation,
Generation of a coloring substance can be suppressed. Further, corrosion of the device can be reduced and contamination of the product can be prevented.

Claims (2)

[Claims] 1. A bisphenol comprising reacting phenol with acetone in the presence of an acidic catalyst, and contacting at least a part of a reaction mixture obtained by removing the acidic catalyst from the obtained crude product with a solid zinc compound. A production method. 2. A phenol and acetone are reacted in the presence of an acidic catalyst, and an adduct of phenol and bisphenol A is separated from a reaction mixture obtained by removing the catalyst from the obtained crude product. A method for producing bisphenol A, comprising recirculating the reaction mixture after contacting with a solid zinc compound.