ISOBUTANE-FORMALDEHYDE ISOPRENE PRODUCTION PROCESS Russian patent published in 1999 - IPC

FIELD: rubber monomer production. SUBSTANCE: process consists in oxidation of isobutane with air or another oxygen-containing mixture at elevated temperature and subsequent separation of unoxidized isobutane and bringing isobutylene and/or tert-butanol into contact with aqueous solution of formaldehyde in presence of acid catalyst. Oxidation of isobutane is carried out under conditions ensuring its conversion predominantly into tert-butanol or mixture of tert-butanol with tert-butyl hydroperoxide (0.01-0.99 wt %). When tert-butyl hydroperoxide is present in oxidation product, it is converted into tert-butanol which is then freed from isobutane and the latter is returned into oxidation zone. Tert-butanol is brought into contact with formaldehyde optionally together with isobutylene and the latter, when separated from reaction mixture, is returned into isoprene synthesis zone. Tert-butyl peroxide is converted into tert-butanol in presence of epoxidation catalyst containing metal salts and/or oxides and/or hydroxides at 70 to 170 C in contact with alkenes containing more than 5 carbon atoms. Resultant tert-butanol, prior to be fed into isoprene synthesis zone, is distilled. In the last subzone of isoprene synthesis zone temperature is maintained by at least 20 C higher than that in the first subzone. EFFECT: improved economical efficiency. 5 cl, 4 dwg, 1 tbl