METHOD FOR PRODUCTION OF ISOPRENE Russian patent published in 1997 - IPC

FIELD: production of high molecular weight compounds. SUBSTANCE: method involves interaction of isobutylene (comprising in C₄ hydrocarbon fraction) with water. The process is carried out in the presence of acid catalyst, it is followed by isolation of main portion of thus prepared tert-butanol by rectification. Then interaction of tert-butanol with formaldehyde is carried out in the presence of acid catalyst at elevated temperature and at increased pressure. Reaction mass is separated into aqueous and oil layers, thus prepared isoprene and isobutylene being isolated of oil layer. Portion of isobutylene (its quantity being 10-100 %) being isolated of oil layer is fed to the stage of hydration of isobutylene. Said portion is used for extraction of tert-butanol (its quantity being 5-50 mass %) and thus prepared extract is returned into reactor for synthesis of isoprene. Extraction is preferably carried out at 60-90 C in counterflow regime in column having efficiency 2-5 theoretical plates. EFFECT: improved efficiency of the method. 2 cl, 2 tbl