Daicel Chemical Industries, Ltd.

Chlorine Engineers Corp., Ltd.

Tadayuki Mitani

Mamoru Endo

Noboru Kamei

Mitsuhiro Kouno

Hiroyuki Harada

Masaaki Ichino

Kazuhiro Hirao

Takashi Hiramoto

A process produces sorbic acid by hydrolyzing a polyester with an aqueous hydrochloric acid solution having a concentration of 15% by weight or less under the application of pressure or at a temperature of 100&deg; C. or higher, which polyester is obtained by reaction between crotonaldehyde and ketene. In this process, the polyester may be hydrolyzed with a 3 to 10% by weight aqueous hydrochloric acid solution at a temperature of from 115&deg; C. to 140&deg; C. A reaction mixture after hydrolysis of the polyester may be subjected to solid-liquid separation and the resulting filtrate may be recycled and reused in the hydrolysis reaction of the polyester. This process can significantly reduce the amount of tar formed during decomposition of the polyester, can produce sorbic acid in a high yield, and can reduce the load on the treatment of waste filtrates formed during purification operation.

Process for producing sorbic acid

A process for producing glyoxylic acid is disclosed which comprises oxidizing glyoxal with an aqueous oxidizing agent composition obtained from nitric acid and a nonoxidizing strong acid present in a concentration of 6 to 40 wt. % in the reaction mixture. Preferably, the nonoxidizing strong acid is hydrochloric acid and the reaction is carried out while nitric acid is gradually added to the reaction mixture so that the concentration of said nitric acid in said reaction mixture does not exceed 1 wt. % during the reaction.

Process for producing glyoxylic acid

A process for the preparation of glyoxylic acid is disclosed which comprises reacting an aqueous solution of glyoxal with chlorine. The reaction is preferably carried out under pressure, under the condition that the hydrochloric acid concentration in the aqueous solution of glyoxal is 1 to 15%. The reaction can be carried out in the presence of a catalytically effective amount of bromine as a catalyst.

Process for preparation of glyoxylic acid

A process for producing glyoxalic acid which comprises electrolytically oxidizing glyoxal in an electrolytic cell comprising at least one anode, at least one cathode and at least one cation exchange membrane therebetween to define an anode compartment(s) and a cathode compartment(s) therein, using an aqueous solution containing glyoxal and halogen ions as an anolyte solution and an aqueous solution containing an inorganic or organic electrolyte as a catholyte solution.

Growing community of inventors

Arai, Japan

Tadayuki Mitani