JPH0465868B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing phenolphthaleins by reacting phthalic anhydride with phenols. Conventionally, phenolphthaleins are produced by heating phthalic anhydride and phenols in the presence of a large amount of a condensing agent such as sulfuric acid, zinc chloride, or thionyl chloride. However, in this conventional method, a large amount of the condensing agent is disposable, which poses problems in terms of cost, environment, etc. As a way to solve these shortcomings,
In recent years, a method has been devised in which phthalic anhydride and phenols are heated in the presence of a cation exchange resin. In this method, the cation exchange resin can be easily separated and recovered from the reaction product and can be reused in the next reaction, but the problem is that the reaction rate is extremely slow. For example, U.S. Pat.
In the method described in No. 4252725, the yield of phenolphthalein is 13.1% even when the reaction is carried out at 120°C.
and the reaction reaches equilibrium. Furthermore, even when a large amount of triphenyl phosphite was added as a dehydration condensation agent, the yield improved only to 19.0%. In view of the above-mentioned circumstances, the present inventors have made intensive studies to solve these problems, and have found that when a specific heat-resistant cation exchange resin is used as a catalyst, the yield of phenolphthaleins is lower than that of the prior art. The present invention was achieved based on the discovery that there is a marked increase compared to the above. That is, with the styrene-divinylbenzenesulfonic acid type cation exchange resin used in the conventional technology, the resin itself has low heat resistance and it is difficult to raise the reaction temperature above a certain temperature. When using a specific cation exchange resin having the following properties, the reaction can be carried out at high temperatures, and phenolphthaleins can be produced in high yield. The method of the present invention will be explained in detail below. Examples of the heat-resistant cation exchange resin used in the present invention include the following substances. polyvinylbenzyl sulfonic acid

[Formula] S content 5-16wt% (described in Japanese Patent Publication No. 46-28415) Poly(ar-halobinylbenzenesulfonic acid)

[Formula] trademark) x/y=2~50 z=1~2 S content 0.5~4.0wt% (described in USP 4053522) Of course, these cation exchange resins have been provided with practical physical properties by appropriate means such as crosslinking. That's good. The heat resistance of these cation exchange resins is such that the performance deterioration rate defined by the formula () is below a certain limit,
In particular, it is essential that the performance deterioration rate after 8 hours in hot water at 180°C is 2.5% or less. Performance reduction rate (%) = (1-total exchange capacity after test/total exchange capacity before test) x 100...() Phenol phthalein that can be produced by the present invention includes phenolphthalein, cresol phthalein, and thymol. Examples include phthalein,
Each is produced by condensing the corresponding phenols and phthalic anhydride. Among them, phenolphthalein has a wide range of uses and is suitable for carrying out the method of the present invention. As the phenols used in the present invention, it is appropriate to use those in which at least one of the ortho-position and the rose-position of the hydroxyl group is not substituted. In the reaction between phenols and phthalic anhydride, it is usually preferable to carry out the reaction with an excess of phenols.
The molar ratio is 2 to 30, more preferably 5 to 20. The amount of cation exchange resin used is preferably about 0.25 to 2 times the molar equivalent of phthalic anhydride based on the exchange capacity. Although it is not necessary to use a particular solvent, an inert solvent such as a hydrocarbon may be used. Good results may be obtained if the reaction is carried out while continuously removing the water produced as a result of the reaction. In the present invention, when producing phenolphthalein by reacting phthalic anhydride with phenols, the reaction temperature is preferably 100°C or higher, more preferably 120°C or higher. The upper limit of the reaction temperature is determined by the heat resistance of the cation exchange resin used; for example, when poly(ar-halobinylbenzenesulfonic acid) is used, the upper limit of the reaction temperature is 150°C.
It is preferable to do the following. The reaction pressure may be normal pressure, preferably under an inert gas flow. EXAMPLES The present invention will be described in more detail below with reference to Examples, but the present invention is not limited to the following Examples unless it exceeds the gist thereof. Examples 1 to 6 Resin manufacturing method () Resin of Example 1 Contains 10% divinylbenzene by weight,
Add 400 ml of methylene dioxide to 100 g of chloromethylated styrene-divinylbenzene crosslinked copolymer (Cl content 22% by weight) having pores with a specific surface area of 41 m ² /g.
After swelling at room temperature for 1 hour, 210 ml of dimethylaniline and 400 ml of demineralized water were added, and the mixture was reacted at 50°C for 5 hours. Then methanol was added to the reaction solution.
Add 200ml, 400g of sodium sulfite, and 300ml of demineralized water,
The reaction was further carried out at 100°C for 18 hours. After the reaction, the resin was separated, thoroughly washed with water, and then dried at 80°C for 8 hours. The resulting resin had 2.34 mmol of sulfonic acid groups per gram. () Resins of Examples 3 to 5 Containing 10% divinylbenzene by weight,
50 g of a styrene-divinylbenzene crosslinked copolymer having a specific surface area of 39 m ² /g and a pore volume of 0.76 ml/g was taken, 300 g of dichloroethane was added thereto, and the mixture was allowed to stand at room temperature for 2 hours to sufficiently swell. Next, 2.5 g of ferric chloride was added, and 100 g of bromine was added slowly so that the temperature did not exceed 20°C. After addition, at 0℃ for 12 hours.
After continuing stirring for an hour, separate the resin, add 1 part of methanol, 2 parts of demineralized water, 1 part of 2N-HCl, 3 parts of demineralized water,
It was washed successively with 1 portion of methanol and dried at 80° C. for 8 hours. Yield: 85.6g. After adding 270 g of dichloroethane to 53.7 g of the brominated cross-linked polystyrene and allowing sufficient swelling, 320 g of 30% olium was added and the mixture was reacted at 30° C. for 12 hours.
After the reaction was completed, 1000 g of water was slowly added and then heated to 90°C to distill off dichloroethane. The resin was then transferred to a column and treated with 4 demineralized water and 5
% saline, 3 parts demineralized water, 4 parts 2N-HCl,
It was washed sequentially with 3 demineralized water. Yield 222ml, amount of sulfonic acid group introduced 2.92meq/g - resin, moisture 60.5%,
The degree of swelling is 3.13ml/g, the introduction rate of sulfonic acid groups is 99% per aromatic ring (0.99 mol of sulfonic acid groups per mol of aromatic ring), and the introduction rate of bromine is 123% by elemental analysis.
% (1.23 mol of bromine atoms per 1 mol of aromatic ring). () Resin of Example 2 A resin was produced in the same manner as in the method for producing the resin of Examples 3 to 5 () except that the divinylbenzene content was 15%. The resulting resin had a sulfonic acid group introduction amount of 2.7 meq/g-resin and a water content of 55%. Reaction A 100 ml glass flask equipped with a stirrer and a reflux condenser was charged with phenol, phthalic anhydride, and the heat-resistant cation exchange resin produced by the above method in the proportions shown in Table 1, and heated under the specified conditions in a nitrogen stream. The reaction was carried out and the product was analyzed by high performance liquid chromatography. The resins used were all converted into acid form with dilute hydrochloric acid, dehydrated, and phenol-swelled. Resin heat resistance test method: Put 20 ml of resin in acid form (H form) and 40 ml of demineralized water into a glass autoclave and heat at 180°C.
heated for an hour. After cooling the autoclave, extract the resin and transfer it to a column with a diameter of 3 cm. 500 ml of 1N hydrochloric acid, 500 ml of demineralized water, 500 ml of 5% NaCl water, 500 ml of demineralized water,
Washed sequentially with 500 ml of 1N hydrochloric acid and 1 portion of demineralized water. 500 ml of 5% NaCl water was passed through the resin over 2 hours, and the column outlet liquid was collected and titrated with 5% NaOH to determine the total amount of sulfonic acid groups in the resin. Separately, the amount of sulfonic acid groups in 20 ml of resin before the test was determined in the same way, and the performance reduction rate was determined from that value ()
Calculated based on the formula. Performance reduction rate (%) = (1-total exchange capacity after test/total exchange capacity before test) x 100...() The results of Examples 1 to 6 above are shown in Table 1. Comparative Example 1 Using commercially available styrene-divinylbenzenesulfonic acid type cation exchange resin SK-106 (manufactured by Mitsubishi Kasei Corporation) as the resin, a reaction was carried out in the same manner as in Examples 1 to 6. Shown in the table. In this case, the reaction solution turned dark and colored, and sulfuric acid due to resin decomposition was detected (barium precipitation method). in this way,
The performance of the resin deteriorated significantly and it was judged that reuse was inappropriate.

【table】

Claims (1)

[Claims] 1. When producing phenolphthaleins by reacting phthalic anhydride and phenols in the presence of an acidic cation exchange resin, the cation exchange resin is 180 defined by the formula (). In warm water at ℃,
1. A method for producing phenolphthaleins, characterized in that a phenolphthalein having a performance decrease rate of 2.5% or less in 8 hours is used. Performance reduction rate (%) = (1 - total exchange capacity after test / total exchange capacity before test) × 100... () 2 Characterized by setting the reaction temperature to 120°C or higher and lower than the heat resistance temperature of the cation exchange resin. A method according to claim 1.