JPH09255607A - Production of bisphenol a - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prolong the life of an acidic ion-exchange resin catalyst used in this process by removing compounds causing catalyst deterioration in the raw materials. SOLUTION: This production process comprises the reaction step where an excessive amount of phenol and acetone are allowed react with each other in the prensece of an acidic ion-exchange resin catalyst to form bisphenol-A, the crystal sparation step where the formed bisphenol-A is precipitated in the from of crystalline adduct with phenol and the purification step where the adduct crystals and subjected to phenol-removal treatment to give purified bisphenol-A. In this process, the phenol prepared by purifying the phenol from the crystal separation step by adsorption treatment is used at last as a part of the phenol to be allowed to reach with acetone and the amount of the adsorbent is 3-25vol.% based on the ion-exchange resin catalyst.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing bisphenol A.

[0002]

2. Description of the Related Art Bisphenol A is obtained by reacting acetone with an excess amount of phenol in the presence of a reaction catalyst such as an acidic ion exchange resin. The obtained reaction mixture contains bisphenol A, phenol and a small amount of by-products. After removing low-boiling substances such as acetone and water, the reaction mixture is cooled to precipitate adduct crystals of bisphenol A and phenol, which crystals are separated from the mother liquor by means such as filtration, and then desorbed. A method of recovering bisphenol A by treating with phenol is common. In such a method, since excess phenol is separated as a mother liquor, it is common to reuse it. This mother liquor contains not only phenol but also bisphenol A and other by-products. Since some of the by-products cause catalyst deterioration, it is desirable that the concentration of these by-products be low. For example, Japanese Patent Laid-Open No. 62-201833 teaches that a part of the mother liquor is purged to prevent the increase of impurities. However, increasing the amount of purging eventually leads to an increase in the raw material consumption rate, which is not desirable in terms of cost. Therefore, a method of removing the compound causing catalyst deterioration from the system without increasing the amount of purge is desired. Further, Japanese Patent Laid-Open No. 6-172241 discloses
In a method for producing bisphenol A using a sulfonic acid type ion exchange resin modified with an alkyl-SH group,
It is taught that the catalyst activity is retained for a long period of time by adding water to the mixture of acetone and phenol prior to the reaction. However, in a system using a normal acidic ion exchange resin and ethyl mercaptan as a reaction accelerator, the addition of water to the raw material causes a marked decrease in the acetone conversion rate. Therefore, a better method of extending the catalyst life without reducing the acetone conversion is desired.

[0003]

SUMMARY OF THE INVENTION It is an object of the present invention to remove a catalyst deterioration-causing compound contained in a raw material and extend the life of an acidic ion exchange resin catalyst to be used.

[0004]

In order to solve the above problems, the inventors of the present invention have conducted extensive studies as to a method for producing bisphenol A which prolongs the life of an acidic ion exchange resin catalyst. It was found that the objective can be achieved by bringing the starting phenol into contact with an adsorbent having an adsorption ability for a compound causing catalyst deterioration, and then carrying out the main reaction. That is, the present invention is a method for producing bisphenol A from phenol and acetone by reacting it in the presence of a reaction catalyst, in which a raw material phenol is brought into contact with an adsorbent, and the amount of the adsorbent used in the reaction catalyst is 3 to 2
The method for producing bisphenol A is characterized in that the content is 5% by volume. The reaction is carried out by reacting acetone with an excess amount of phenol in the presence of a reaction catalyst such as an acidic ion exchange resin. This reaction can be performed under any known conditions. A reaction accelerator may be added. One of the methods for recovering bisphenol A from the reaction mixture is one in which low boiling substances such as acetone and water are separated from the reaction mixture, and then crystals of an adduct of bisphenol A and phenol are precipitated and filtered. Is a method of dephenolizing the adduct by separating the adduct and mother liquor. Among the components separated when the bisphenol A is recovered, unreacted acetone and phenol are reused as raw materials. Acetone is recovered from the step of separating the low boiling point component from the reaction mixture by a means such as distillation, and most of the phenol is recovered as the mother liquor. In the mother liquor at this time, if the amount of by-products is small, the total amount may be returned to the reaction step as raw material phenol without purification, but if the total amount is returned as it is, by-products will accumulate and adversely affect the quality of bisphenol A. The rest is purified and recovered in the step of removing the by-product from the system. Therefore, a part of the mother liquor is reused as the raw material phenol without being purified, but since the by-product in the mother liquor also contains the compound that causes the deterioration of the acidic ion exchange resin catalyst, Needs to be removed. It is known that the compounds that cause catalyst deterioration are removed to the outside of the system along with by-products when purged, but at the same time, bisphenol A in the mother liquor is also removed to the outside of the system, increasing the amount of purification in this step. If this happens, the raw material consumption rate will deteriorate and it will be economically disadvantageous.

Therefore, the inventors of the present invention can prevent deterioration of the catalyst with time by carrying out the main reaction after contacting the raw material phenol containing the recovered mother liquor with an adsorbent having an adsorption ability for the compound causing the catalyst deterioration. It has been found that an extension of catalyst life can be achieved. Since the compound that causes catalyst deterioration is considered to be an aromatic compound, any adsorbent may be used as long as it is a hydrophobic organic substance or a porous inorganic substance, but physically or chemically with respect to the mother liquor to be contacted. A stable one is preferable. Specifically, acidic ion exchange resins, crosslinked polystyrene resins, activated carbon, zeolite, silica-alumina, silica gel, alumina, activated clay, etc. are suitable, but acidic ion exchange resins similar to the reaction catalyst of bisphenol A are most suitable. preferable. Further, as the acidic ion exchange resin, any of gel type, porous type and high porous type can be used.

The amount of adsorbent is 3 by volume with respect to the reaction catalyst.
-25% is preferable. If it is less than 3%, the life of the adsorbent is too short and the adsorbent must be replaced frequently, which is not preferable in operation. If it exceeds 25%, not only is the adsorber too large in terms of equipment, but also the operating cost for exchanging the adsorbent increases, which is not preferable.

The adsorbent is generally packed in a vessel as a fixed bed, but it may be used as a fluidized bed. In addition, the adsorbent preferably has a small particle size in order to maximize the adsorption area, but if it is too small, pressure loss when it is packed in a container as a fixed bed causes a problem.
mm is preferable, and 0.2 to 1 mm is more preferable. The position at which the adsorbent is brought into contact with the raw material phenol is a line where the mother liquor is separated from the crystal separation step and recovered as the raw material phenol, or a line immediately before the acetone is mixed with the raw material phenol.

When the temperature at which the raw material phenol and the adsorbent are brought into contact with each other is high, it is not preferable because impurities are generated by a side reaction between the raw material phenol and the adsorbent, and when the temperature is low, the viscosity of the raw material phenol is low. Is increased, which causes a problem of pressure loss of the container filled with the adsorbent as the fixed bed, which is not preferable. Specifically, the temperature is preferably 50 to 120 ° C, more preferably 60 to 80 ° C. In addition, normal raw material phenol
The adsorbent is brought into contact with the adsorbent as a fixed bed in a container filled with the adsorbent, and the higher the space velocity at that time, the smaller the adsorbent filling amount can be, but the risk of insufficient adsorption of the compound causing the catalyst deterioration. There is. On the contrary, if the space velocity is slow, the adsorbent filling amount increases, which is not economical. The specific space velocity is LHSV
Is preferably ¹ to 50 Hr ^−1, more preferably 3 to
It is 30 Hr ^-1 .

The adsorbent will break through with time when it is brought into contact with the raw material phenol for a long time. In this case, if the adsorbent is washed with a washing liquid containing no compound causing catalyst deterioration, the adsorbent can be repeatedly used. The cleaning liquid used in this case is preferably phenol recovered in the distillation step in the bisphenol A production facility or commercially available phenol produced in an industrial scale production facility.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, the catalyst deterioration-causing compound contained in the recovered raw material phenol is removed by the adsorbent before the excess phenol is reacted with acetone, so that the catalyst deterioration can be prevented. It is estimated that the catalyst life is extended.

[0011]

【Example】

Reference Example 1 After separating low-boiling substances such as acetone and water from the reaction mixture,
Precipitated crystals of adduct of bisphenol A and phenol, filtered mother liquor (phenol 85%, bisphenol A 8%, 2,4-isomer 5%, other impurities 2%) 6
6 g of the adsorbent was added to 00 g, and the mixture was stirred at 60 ° C. for 5 hours for adsorption treatment, and then the adsorbent was removed by filtration, and the mother liquor was mixed with an acidic ion exchange resin (Am produced by Rome & Haas Co.
2 g of berlyst31) was added, and the mixture was stirred at 80 ° C. for 24 hours to poison the acidic ion exchange resin. This acidic ion-exchange resin was collected by filtration, and 18 g of phenol was added to it.
Acetone (0.79 g) and ethyl mercaptan (38 mg) were added, and the mixture was stirred at 70 ° C. for 2 hours to carry out a reaction. As the adsorbent in the adsorption treatment, cross-linked polystyrene resin, zeolite, activated carbon and acidic ion exchange resin were used. The acetone conversion rate at this time is shown in Table 1. Comparative Example 1 The same experiment as in Reference Example 1 was performed except that the adsorption treatment of the recovered mother liquor was not performed. The acetone conversion is also shown in Table 1. (Below margin)

[Table 1] Example 2 A glass tube having a temperature controller was charged with 5 ml of an acidic ion exchange resin (SK-104H manufactured by Mitsubishi Chemical) and 75 ° C.
The same mother mother liquor as described above was continuously circulated at 50 ml / Hr while maintaining the above temperature to perform adsorption treatment. 30 parts by weight of acetone was added to 1000 parts by weight of the recovered mother liquor subjected to this adsorption treatment as a raw material, and 2 parts by weight of ethylimcaptan as a reaction accelerator was added to prepare an acidic ion exchange resin (SK-1 manufactured by Mitsubishi Chemical Corporation).
04H) at 50 ° C. in a flow reactor filled with 50 ml,
50 ml / Hr was continuously charged and reacted. Table 2 shows the transition of the acetone conversion rate for each number of days passed through the flow reactor. Comparative Example 2 The same experiment as in Example 2 was performed except that the adsorption treatment of the recovered mother liquor was not performed. Similarly, Table 2 shows the transition of the acetone conversion rate for each number of days passed through the flow reactor.

[Table 2]

[0012]

According to the present invention, the catalyst deterioration-causing compound is adsorbed and removed, and the deterioration of the catalyst activity can be prevented. As a result, the life of the catalyst is extended, and the number of times of replacement of the catalyst can be reduced.

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Claims (2)

[Claims] 1. Excess phenol and acetone are reacted in the presence of an acidic ion-exchange resin catalyst to produce bisphenol A, which is sent to a crystal separation step in which it is precipitated as an adduct crystal with phenol, and the separated bisphenol A and phenol are separated. In the method for producing bisphenol A in which purified bisphenol A is recovered by dephenolizing adduct crystals, at least a part of the phenol to be reacted with acetone is obtained by adsorption-treating the raw material phenol obtained from the crystal separation step, The method for producing bisphenol A, wherein the adsorbent used in this adsorption treatment is 3 to 25% by volume with respect to the acidic ion exchange resin catalyst. 2. The method for producing bisphenol A according to claim 1, wherein the adsorbent is the same as the acidic ion exchange resin used for reacting phenol and acetone.