| 摘要 |
FIELD: purification methods for polycarboxylic acid derivatives. SUBSTANCE: method of purifying C-C-di- and polycarboxylic acid esters or their anhydrides and C-C- alifatic monoatomic alcohols prepared in presence of organotitanium catalysts including neutralization of raw ester with aqueous alkali agent solution at elevated temperature, live superheated steam treatment, sorbent treatment, and filtration has the following features. As alkali agent, sodium hydroxide is used in amounts 2- 15% based on weight of reaction mixture. Neutralization of raw esters and steam treatment are performed simultaneously at 50-110 C, steam temperature being 130-250 C and its amount being 5-40 wt % based on reaction mixture. Prior to be sorbent-treated, mixture is dehydrated and, after filtration, treated with steam overheated to 170-250 C under residual pressure 20-200 torr. If necessary, additional filtration may be carried out after the 2nd steam treatment. Yield of product is 99.7%. EFFECT: achieved one-percent increase in yield, improved appearance and color index of product. 4 cl, 3 tbl |
