SU502004A1 - The method of obtaining 4-hydroxy-4 "-carboxydiphenylsulfone - Google Patents

Description

- SOj / oVСООИ

Naoi

In order to eliminate the above disadvantages of the proposed method, 4-methyl-4chlorodiphenylsulfone is treated with alkali metal dichromate, for example sodium bichromate, in an aqueous medium at 270-290 ° C and the molar ratio between sulfone and bichromate is 1: (1.5-2, 0).

.) - СНз + М2Сг207 .- / OV S02- / OV OO + Сг20з Н.20 aCl

-but

The process can be carried out in the presence of sodium carbonate or sodium hydroxide, followed by separation of the target product in a known manner.

The process takes 1-2 hours as follows:

To increase the yield of the target product, it is advisable at the end of the process to introduce small amounts (up to 1 mol per 1 mol of the starting sulfone) of caustic soda or sodium carbonate. The yield of the target product in this case reaches 95%.

The resulting chromium oxide is easily separated by filtration. Then we can. It can be converted to dichromate by oxidizing the air with oxygen in an aqueous medium in the presence of sodium carbonate or sodium bicarbonate.

The proposed method allows the process of producing 4-hydroxy-4-carboxy-diphenylsulfone in one stage, significantly reducing the process time and the consumption of starting products. In addition, the simultaneous oxidation and hydrolysis allows the use of heat released during the exothermic oxidation reaction to carry out hydrolysis, which occurs at temperatures higher than 200 ° C. A neutral or weakly alkaline medium is maintained in the reaction zone during the simultaneous oxidation and hydrolysis reactions. The proposed method is also characterized by a high yield of the target product (up to 95%).

Example 1. A mixture of 26.6 g (0.1 mol) of 4-methyl-4-chlorodiphenylsulfone, 44.7 g (0.15 mol) of sodium bichromate in the form of Na2Cr2072H2O and 500 ml of water is heated for 2 hours at

270 ° C, then filtered to remove chromium oxide. The filtrate is acidified with 20–30% hydrochloric or sulfuric acid to a pH of 1–2, and the precipitated precipitate is filtered and dried. 24.8 g (89.2%) of the expected product are obtained.

Example 2. Analogously to example 1 of 26.6 g (0.1 mol) of 4-methyl-4-chlorodiphenylsulfone, 44.7 g (0.15 mol) of sodium dichromate in the form of Na2Cr2O7-21120, and 500 ml of water at 280 ° With the addition of 4 g (0.1 mol) of caustic soda in the form of an aqueous solution, 26 g (93.5%) of the desired product are added with 1 hour before the end of the reaction.

Claims (2)

1. A method of producing 4-hydroxy-4-carboxy-diphenylsulfone by oxidizing 4-methyl-4-chlorodiphenylsulfone followed by hydrolysis of the resulting product with heating, characterized in that, in order to simplify the process, 4-methyl 4-chlorodiphenylsulfo is treated with an alkali metal dichromate, for example, dichromate sodium in an aqueous medium at 270–290 ° С and a molar ratio between the initial components 1: (1,5-2,0). 2. A method according to claim 1, characterized in that the process is carried out in the presence of sodium carbonate or sodium hydroxide.