Polybutylene glycol di:ester prepn. - by polymerising THF in presence of carboxylic acid anhydride and fixed catalyst bed of fuller's earth

摘要

In the parent patent polybutylene glycol dicarboxylic acid ester of formula RCOO-(CH2CH2CH2CH3)-n COR1 (I) (where R and R1 are alkyl, carboxy contg. opt. ethylenicall unsatd. aliphatic gp. or a carboxy contg. aromatic gp. and n is 2-200) is prepd. by polymerising THF in the presence of carboxylic acid anhydrides (II) and Fuller's earth (III) with a water content 3wt. as a catalyst. In this addition the catalyst is in a fixed catalyst bed and is contacted with a mixt. of THF and the anhydride. (III) pressed and dried at 100 degrees C is not destroyed by the THF or (II) but maintains its shape for a very long time e.g. =1 year, maintains its original shape and shows no abrasion. Since removal of the powdered catalyst in the absence of air is no longer required, the process is simplified and the quality of the prod. esp. colour and polymerisation degree, are improved and can be reproduced. (III) remains active continuously so long as highly pure THF is used.