JP4376727B2 - Bisphenol isomerization catalyst - Google Patents

Description

  The present invention relates to a method for isomerizing by-products in the production of bisphenols.

  Bisphenols, especially 2,2-bis (4-hydroxyphenyl) propane (hereinafter referred to as p, p′-BPA) is useful as a raw material for polycarbonate resins and epoxy resins, and its demand has been greatly increased in recent years. It is growing.

  p, p'-BPA is usually produced by reacting phenol and acetone in the presence of a homogeneous acid or solid acid catalyst. In the reaction, in addition to the desired product, by-products such as 2- (2-hydroxyphenyl) -2- (4-hydroxyphenyl) propane (hereinafter referred to as o, p′-BPA), chromans, and trisphenol. Is a factor that reduces the yield of the target p, p′-BPA. The p, p′-BPA produced by the reaction is, for example, by removing unreacted acetone and by-product water by distillation or the like, and then bonding the equimolar amount of p, p′-BPA and phenol by lowering the temperature. The adduct crystals are precipitated, separated from the mother liquor, and then purified by removing phenol from the adduct crystals. Further, since p, p′-BPA is also present in the filtrate discharged from the crystallization stage, in order to improve the yield, this filtrate is usually concentrated and further crystallized to obtain p, p′-BPA. Measures are taken such as recovering BPA or circulating a part of the filtrate to the reaction step or the purification step. Here, in order to further improve the yield, for example, among impurities contained in the filtrate discharged from the crystallization step, p, p′-BPA such as o, p′-BPA and trisphenol can be relatively easily performed. It is necessary to isomerize a substance that can be converted into isomerization in the presence of an acidic catalyst.

  As the catalyst in the isomerization reaction, it is well known to use a sulfonic acid type strongly acidic ion exchange resin and a sulfonic acid type strongly acidic ion exchange resin partially modified with lower aminothiols such as 2-aminoethanethiol. It has been. However, when these catalysts are used, there is a problem that the rate of isomerization is slow, and an undesired product is generated due to decomposition of bisphenols in the reaction, resulting in a decrease in yield.

  As a measure for improving the reaction rate and selectivity in isomerization, there is a method of using an acidic ion exchange resin modified with a modifier. JP-A-57-98229 discloses a strongly acidic cation exchange resin modified with mercapto lower alkylpyridine as a catalyst for improving the isomerization reaction rate (Patent Document 1). JP-A-01-135736 describes that a catalyst obtained by modifying a strongly acidic cation exchange resin with an alkyl mercaptoamine containing two mercapto groups in the molecule is used for isomerization (patent). Reference 2). Further, JP 05-293382 discloses a catalyst obtained by modifying a strongly acidic ion exchange resin with mercapto-thiadiazoles or mercapto-benzothiazolidines, and JP 05-271132 discloses a strongly acidic ion exchange resin with mercapto-thiazoles. The reformed catalyst is clearly shown (Patent Document 3 and Patent Document 4). However, all of these catalysts have the disadvantage that the modifier is expensive and the catalyst price is high.

An object of the present invention is to provide an inexpensive and effective catalyst for allowing an isomerization reaction to proceed at a high speed and with a reduced amount of undesirable products.
JP 57-98229 A JP-A-01-135736 JP 05-293382 A JP 05-271132 A

    The present invention relates to an isomerization catalyst for bisphenols, and an object of the present invention is to provide a low-cost ion exchange resin catalyst that allows the reaction to proceed efficiently while suppressing the amount of by-products generated by the decomposition of bisphenols.

  As a result of intensive studies to solve the above problems, the present inventors have found that the acidic functional group of the acidic ion exchange resin has a cationic compound of (formula 1) and / or (formula 2) and / or a cationic nitrogen-containing compound. By using a modified acidic ion exchange resin ion-bonded with a heterocyclic compound as a catalyst, it is possible to increase the selectivity of bisphenols without losing activity in the isomerization reaction of by-products generated in the bisphenol production process. The present inventors have found that this can be done and have completed the present invention.

That is, the present invention is an acidic ion exchange resin in which at least one cationic compound selected from the following (A), (B), and (C) is ionically bonded in a method for isomerizing by-products generated in the production of bisphenols. Is used as a catalyst.
(A) Cationic compound represented by (Formula 1)

(In the formula, A represents a nitrogen atom or a phosphorus atom, and R1, R2, R3, and R4 each independently represent hydrogen or an alkyl group having 1 to 20 carbon atoms that does not include any of a mercapto group and a mercapto group equivalent. Or an aryl group, and at least one of R1, R2, R3, and R4 is other than a hydrogen atom)
(B) Cationic compound represented by (Formula 2)

(Wherein R5, R6, and R7 each independently represents an alkyl group or aryl group having 1 to 20 carbon atoms, which does not include any of a mercapto group and a mercapto group equivalent)
(C) A cationic nitrogen-containing heterocyclic compound containing neither a mercapto group nor a mercapto group equivalent.

  According to the method of the present invention, the by-product produced in the production of bisphenols can be isomerized to the desired bisphenols at a low cost and in a high yield.

  Examples of the acidic ion exchange resin used in the present invention include those of a type in which a sulfo group is introduced into a styrene-divinylbenzene copolymer, generally called a strong acidic ion exchange resin, and a perfluoroalkyl sulfone such as Nafion. Examples include acid-based resins. An ion exchange resin having a sulfone group introduced into a styrene-divinylbenzene copolymer is preferably used. Typically, sulfonic acid type styrene-divinylbenzene ion exchange resins are commercially available under the trade names such as Levacit (Bayer), Dowex (Dow Chemical), Amberlite (Rohm and Haas Company), etc. Has been. Styrene-divinylbenzene ion exchange resins include a resin having a fine network structure (gel type) and a resin having a huge network structure (macroporous type), and any of these resins can be used. .

  The modified acidic ion exchange resin in the present invention ion-bonds the cationic compound and / or the cationic nitrogen-containing heterocyclic compound represented by (Formula 1) and / or (Formula 2) to the above acidic ion exchange resin. Can be obtained.

(In the formula, A represents a nitrogen atom or a phosphorus atom, and R1, R2, R3, and R4 each independently represent hydrogen or an alkyl group having 1 to 20 carbon atoms and containing neither a mercapto group nor a mercapto group equivalent. Or an aryl group, and at least one of R1, R2, R3, and R4 is other than a hydrogen atom)

(In the formula, R5, R6, and R7 each independently represent an alkyl group or an aryl group having 1 to 20 carbon atoms that does not include any of a mercapto group and a mercapto group equivalent)

  At this time, a method of ion-exchanging an acidic ion exchange resin with a cationic compound represented by (formula 1) can be used, but an acidic ion represented by a charge neutral compound represented by (formula 3) is used as a precursor. It may be cationized by contacting with an exchange resin. Similarly, the ion exchange resin may be ion-exchanged with a cationized nitrogen-containing heterocyclic compound, or the neutral precursor nitrogen-containing heterocyclic compound may be cationized by contacting with the acid ion-exchange resin. You can also.

(In the formula, A represents a nitrogen atom or a phosphorus atom, and R 1, R 2, and R 3 are each independently an alkyl group or aryl having 1 to 20 hydrogen atoms or containing no mercapto group or mercapto group equivalent) And at least one of R 1, R 2 and R 3 is other than a hydrogen atom).

  In the cationic compound represented by (formula 1) used in the present invention, A in the formula represents a nitrogen atom or a phosphorus atom, and R 1, R 2, R 3, and R 4 are each independently hydrogen or 1 carbon atom. An alkyl group or an aryl group having 1 to 16 carbon atoms, preferably 1 to 16 carbon atoms, more preferably 1 to 12 carbon atoms, and containing neither a mercapto group nor a mercapto group equivalent, and R1, R2, R3 And at least one of R4 is an alkyl group having 1 to 20 carbon atoms, preferably 1 to 16 carbon atoms, more preferably 1 to 12 carbon atoms, and containing neither a mercapto group nor a mercapto group equivalent. Or it is an aryl group. The structure of R1, R2, R3, and R4 is not particularly limited as long as neither the mercapto group nor the mercapto group equivalent is included, and includes amino group, ammonium group, carbonyl group, carboxyl group, sulfonyl group, It may have a functional group such as a sulfone group, a hydroxyl group, a nitrile group, a nitro group or an alkoxy group, or a halogen atom. R1, R2, R3 and R4 may be bonded to each other to form a ring. The mercapto group equivalent refers to a precursor that generates a mercapto group, and examples thereof include thiazolidines and thioethers. As the compound represented by (Formula 1), tetramethylammonium chloride, tetraethylphosphonium chloride, tetraphenylphosphonium chloride and the like are preferably used. As the charge neutral compound represented by (Formula 3), trimethylamine, triethylamine, triphenylphosphine, or the like is preferably used.

  The cationic compound represented by (formula 2) used in the present invention is such that R5, R6, and R7 each independently have 1 to 20 carbon atoms, preferably 1 to 16 carbon atoms, An alkyl group or an aryl group having 1 to 12 carbon atoms and containing neither a mercapto group nor a mercapto group equivalent is preferable. The structure of R5, R6, and R7 is not particularly limited as long as neither the mercapto group nor the mercapto group equivalent is included, and includes amino group, ammonium group, carbonyl group, carboxyl group, sulfonyl group, sulfone group And may have a functional group such as a hydroxyl group, a nitrile group, a nitro group or an alkoxy group, or a halogen atom. R5, R6, and R7 may be bonded to each other to form a ring. As the compound represented by (Formula 2), trimethylsulfonium iodide is preferably used.

  The cationic nitrogen-containing heterocyclic compound used in the present invention does not contain a mercapto group and / or a mercapto group equivalent. Further, the number of ring members of the ring containing the nitrogen atom of this cationic nitrogen-containing heterocyclic compound is preferably 3 to 8, and more preferably 5 to 7. In addition, this compound may be a monocyclic compound or a polycyclic compound having a condensed ring, and further may have one nitrogen atom or two or more nitrogen atoms. Examples of the cationic nitrogen-containing heterocyclic compound or a neutral precursor thereof include compounds having a pyridine ring, compounds having a pyrrole ring, etc., and preferably pyridine, N-methylpyridine, pyrrole, N-methylpyrrole. Etc. are used.

  As the modified acidic ion exchange resin in the present invention, one of the cationic compound represented by (Formula 1), the cationic compound represented by (Formula 2) or the cationic nitrogen-containing heterocyclic compound is used alone. Alternatively, a plurality of types may be used in combination, and the cationic compound represented by (Formula 1) and / or the cationic compound represented by (Formula 2) and / or the cationic nitrogen-containing complex. In addition to the ring compound, it may be partially neutralized with other cations such as ammonium cation or metal cation. In general, the cationic compound and the cationic nitrogen-containing heterocyclic compound represented by (Formula 1) are commercially available at a lower cost than the cationic compound represented by (Formula 2), and When a compound having a sulfur atom is mixed into a product, it may cause coloring of bisphenols and deteriorate the quality. Therefore, the cationic compound and / or the cationic nitrogen-containing heterocyclic compound represented by (formula 1) It is desirable to use an ion exchange resin modified with.

  Preparation of the modified acidic ion exchange resin catalyst in the present invention is carried out by using a cationic compound represented by (formula 1) and / or a cationic compound represented by (formula 2) and / or immediately before being finally used in the reaction. It is sufficient that the cationic nitrogen-containing heterocyclic compound and the functional group are ionically bonded, and the cationic compound and / or the cationic nitrogen-containing heterocyclic compound in such a state can be prepared directly or using a precursor. I do not care. For example, in the case of amines, viridines, and pyrroles, not only gases and aqueous solutions thereof, but also hydrochlorides, sulfates, acetates, sulfur trioxide complexes, etc. can be dissolved in a solvent, and ammoniums and phosphoniums can be used. Chlorides, bromides, iodides, hydroxides and the like may be used by dissolving them in a solvent.

  The reforming method is not particularly limited. For example, as a simple method, a method in which it is dissolved in a solvent such as water or an organic solvent and contacted in a liquid phase can be used. When a volatile substance is used, it is modified by contacting with an ion exchange resin in a gas phase. It doesn't matter if you do quality. Furthermore, after neutralizing the ion exchange resin with an equivalent or excess amount of a cationic compound or its precursor, the ion exchange resin is brought into contact with an acidic solution to partially return it to an acid form. A method that takes the form of an acidic ion exchange resin may be used. Also, the contact method of the resin with the modifier is a batch type in which the resin is suspended in the container and the solution of the modifier is injected, and the resin is filled in the reaction container and the modifier solution is distributed. Although a method such as an equation is conceivable, any method may be used. In the modification, in order to uniformly introduce the modifier into the resin, it is desirable that the contact time between the resin and the modifier solution is at least 10 minutes.

  The modification rate of the acidic ion exchange resin in the present invention is 0.1 to 50 mol% of the total sulfonic acid groups. If the reforming rate is too high, the activity decreases due to a decrease in the acid amount of the catalyst, and the isomerization rate decreases. On the other hand, when the reforming rate is lower than 0.1 mol%, the effect of the reforming cannot be obtained sufficiently.

  The isomerization reaction is performed, for example, by bringing the filtrate discharged from the step of separation and purification by solid-liquid separation into contact with a catalyst after crystallization of the target bisphenol in the production process of bisphenols. This isomerizes by-products such as 2- (2-hydroxyphenyl) -2- (4-hydroxyphenyl) propane to the desired bisphenols.

  The reaction is usually carried out in the presence of substantially anhydrous or small amount of water. It is known that the yield of the isomerization reaction is improved by the presence of a small amount of water. On the other hand, since water is adsorbed on the ion exchange resin and decreases the reaction rate, the presence of a large amount of water is not preferable. Preferably, the concentration of water is 0.05 to 1.5% by weight, more preferably 0.1 to 1.0% by weight.

  Although there is no restriction | limiting in particular also about reaction temperature, Preferably it is 40-110 degreeC, More preferably, it is the range of 50-100 degreeC. If the reaction temperature is extremely low, the productivity of the desired bisphenols decreases due to a decrease in the reaction rate. On the other hand, if the reaction temperature is too high, it is not economical because an undesirable by-product of the side reaction leads to an increase in by-products and further to a decrease in catalyst life.

  The present invention can be carried out by any of batch, semi-batch and continuous flow methods. There are various methods for charging the catalyst into the reactor, such as a fixed bed, a fluidized bed, and a suspended fluidized bed, and any method may be used. From the viewpoint of productivity, it is preferable to use a fixed bed reactor.

  Next, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the following examples.

(1) Preparation of the modified ion exchange resin catalyst After 15 grams of dry weight of Lebatit K1221 (manufactured by Bayer) was swollen with water, 1.17 g of triethylamine and 12 ml of 1N hydrochloric acid were ion exchanged while stirring in 300 ml of ion exchange water. A triethylamine aqueous solution dissolved in 150 ml of water was slowly added dropwise. After completion of dropping, the mixture was further stirred for 4 hours, and then the catalyst was recovered by filtration and washed with ion-exchanged water. Then, it vacuum-dried at 80 degreeC for 10 hours or more, and obtained the catalyst 1 with the modification rate of 15%.

  The acid amount of the catalyst can be obtained by a general method for measuring the exchange capacity of an acidic ion exchange resin. In the present invention, 0.3 g of the dry resin was stirred in 50 ml of 10% NaCl aqueous solution for 30 minutes, and the total amount of the filtrate was titrated with 0.1 N NaOH, and obtained from the titration curve. As a result of measuring the acid amount of the catalyst 1 by this method, it was 4.30 meq / g (dry weight basis).

(2) Isomerization reaction A 200 ml round bottom flask was charged with 5.0 g of the catalyst prepared in (1) and 25 g of phenol, and swollen overnight at 80 ° C. Next, after removing acetone and water from the reaction solution obtained by condensing phenol and acetone in the presence of an acid catalyst, crystallization was performed, and after solid-liquid separation when a bisphenol A adduct was obtained, the filtrate was added to the flask, and phenol was further added. In addition, after adjusting so that it might become the reaction liquid composition of Table 1, it was made to react by keeping at 80 degreeC, fully stirring. After 8 hours, stirring was stopped and the reaction solution was sampled and analyzed by liquid chromatography. As a result of the analysis, it was confirmed that the heavy component irreversibly produced by the side reaction of the isomerization reaction increased. This heavy component was also contained in the reaction raw material. The results are shown in Table 1.

  Catalyst 2 was obtained in the same manner as in Example 1, except that an aqueous solution of trimethylsulfonium iodide in which 1.47 g of trimethylsulfonium iodide was dissolved in 150 ml of ion-exchanged water was used instead of the aqueous solution of triethylamine. As a result of measuring the acid amount of this catalyst, it was 4.20 meq / g (dry weight basis). In addition, the isomerization reaction was performed under the same conditions as in Example 1 except that catalyst 2 was used instead of catalyst 1. The results are shown in Table 1.

  Catalyst 3 was obtained in the same manner as in Example 1 except that an aqueous pyridine solution in which 0.91 g of pyridine was dissolved in 150 ml of ion-exchanged water was used instead of the aqueous triethylamine solution. As a result of measuring the acid amount of this catalyst, it was 4.25 meq / g (dry weight basis). Further, the isomerization reaction was carried out under the same conditions as in Example 1 except that catalyst 3 was used instead of catalyst 1. The results are shown in Table 1.

[Comparative Example 1]
The isomerization reaction was carried out under the same conditions as in Example 1 except that commercially available Levatite K1221 that had been sufficiently dried as a catalyst and was not modified was used. The results are shown in Table 1. Moreover, it was 5.13 meq / g (dry weight basis) as a result of measuring the acid amount of this commercially available lebacit K1221.

  When this result was compared with Examples 1, 2, and 3, in Examples 1, 2, 3 and Comparative Example 1, all reached isomerization equilibrium at the time of sampling, but the amount of increase in unwanted heavy content was It can be seen that the catalysts 1, 2 and 3 are less than unmodified K1221.

[Comparative Example 2]
The catalyst 4 was obtained in the same manner as in Example 1 except that instead of the triethylamine aqueous solution, a 2-aminoethanethiol hydrochloride aqueous solution in which 1.31 g of 2-aminoethanethiol hydrochloride was dissolved in 150 ml of ion-exchanged water was used. It was. As a result of measuring the acid amount of this catalyst, it was 4.15 meq / g (dry weight basis). In addition, the isomerization reaction was performed under the same conditions as in Example 1 except that catalyst 4 was used instead of catalyst 1. The results are shown in Table 1.

  When this result was compared with Examples 1, 2, and 3, in Examples 1, 2 and 3, the reaction reached equilibrium at the time of sampling, whereas in Comparative Example 2, the reaction did not reach equilibrium, and catalyst 4 was It can be seen that the isomerization rate is slower than that of catalysts 1, 2 and 3.

  By isomerizing impurities produced as a by-product in the production process of bisphenols using the catalyst according to the present invention, the isomerization reaction to the desired bisphenols can proceed efficiently and at low cost. Thus, the yield of the target bisphenol can be improved.

Claims (3)

A by-product produced in the production of bisphenol A, the filtrate discharged from the step of crystallizing bisphenol A from a reaction solution obtained by condensing phenol and acetone in the presence of an acid catalyst, followed by separation and purification by solid-liquid separation. In the method of isomerizing the by-products in
Using the acidic ion exchange resin ion-bonded with at least one cationic compound selected from the following (A), (B), and (C) as a catalyst , the by-product in the filtrate is isomerized. Method.
(A) Cationic compound represented by (Formula 1)

(In the formula, A represents a nitrogen atom or a phosphorus atom, R 1, R 2, R 3, and R 4 are each independently an alkyl group having 1 to 20 hydrogen atoms or a mercapto group and containing neither thiazolidine nor thioether ; Represents an aryl group, and at least one of R1, R2, R3, and R4 is other than a hydrogen atom)
(B) Cationic compound represented by (Formula 2)

(In the formula, R5, R6, and R7 each independently represent a mercapto group having 1 to 20 carbon atoms and an alkyl group or aryl group that does not contain thiazolidine or thioether )
(C) A cationic nitrogen-containing heterocyclic compound containing no mercapto group and any of thiazolidine and thioether .   The method according to claim 1, wherein 0.1 to 50 mol% of all acidic functional groups present in the acidic ion exchange resin are ionically bonded to the cationic compound.   The method according to claim 1 or 2, wherein the acidic ion exchange resin is obtained by introducing a sulfone group into a styrene polymer and / or a styrene-divinylbenzene copolymer.