| 摘要 |
Esters or linear polyesters of molecular weight at least 400 and below 5000, are purified by passing a stream downwardly through a fractionating column with a gas-liquid contacting means and an inert gas stream upwardly at a temperature at least 100 DEG C. and a linear velocity of from 3 to 100 feet per second, and collecting the ester or polyester at the base. The ester is preferably preheated to 100 DEG to 250 DEG C. and is neutralized before or after the stripping stage. Superheated steam, nitrogen, methane and propane may be the inert gases and esters specified are didecyl and dioctyl phthalate, bis - (2,2,4 - trimethylpentyl) azelate, 2,2,4-trimethylpentane - 1,3 - dipelargonate, glycerine triesters and the pelargonate of trimethylol propane and the polyesters are reaction products of a diol and dicarboxylic acid terminated with a monohydric alcohol or monocarboxylic acid and lists of glycols, dicarboxylic acids and terminating compounds are given. The invention is also particularly applicable to esters prepared from dicarboxylic acid and glycol monoesters with a secondary hydroxyl group in the 3-position, in the presence of tin catalysts and compounds of lower boiling point are stripped from the product.ALSO:Linear polyesters of molecular weight at least 400 and below 5000 are purified by passing a stream downwardly through a fractionating column with a gas-liquid contacting means, and an insert gas stream upwardly at a temperature at least a 100 DEG C. and a linear velocity of from 3 to 100 feet per second, and collecting the polyester at the base. The ester is preferably preheated at 100 to 250 DEG C. and is neutralized before or after the stripping stage. Superheated steam, nitrogen, methane and propane may be the inert gases and polyesters specified are the reaction products of a diol and dicarboxylic acid terminated with a monohydric alcohol or a monocarboxylic acid and lists of glycols, dicarboxylic acids and terminating compounds are given. The invention is also particularly applicable to esters prepared from dicarboxylic acid and glycol monoesters with a seconday hydroxyl group in the 3-position in the presence of tin catalysts and compounds of lower boiling point are stripped from the product. |
