Continuous prepn. of uniform polyethers - from alkylene oxide and poly:ol, in divided reaction zone, esp. for use in making polyurethane

摘要

Continuous process is described for the prepn. of polyethers by reaction of an epoxyalkane on a polyol in presence of an alkali metal catalyst is carried out in a reaction zone divided into is not 6 sections. The monomer, and the polyol contg. in soln. 1-20 wt. % (calculated as KOH) of an alkali metal alcoholate, with 0.05-0.5 wt. % of water, are fed upwards into the first section; the molar ratio of epoxyalkane in the first section is 1:1.5. The prod. is purified, or is reacted with another epoxyalkane, followed by purification, to give block copolymers. A uniform prod. is obtd. The process and plant are relatively simpler. A relatively smaller condenser can be used, since the amt. of unreacted epoxyalkane vapour is relatively low 4-5x lower.