ISOPRENE PRODUCTION PROCESS Russian patent published in 1999 - IPC

FIELD: rubber monomer production. SUBSTANCE: isoprene is produced by liquid-phase interaction of isobutylene and/or tert-butanol with formaldehyde solution in presence of acid catalysts in at least two reaction zones wherein synthesis of isoprene precursors and their decomposition into isoprene are effected. Decomposition occurs in presence of organic solvent, in particular, 4,4- dimethyldioxane and/or 4-methyl-5,6-methyldihydropyran and/or other isoprene synthesis by-products having boiling temperatures above 80 C, preferably above 120 C, or mixed solvent with boiling temperature higher than 65 C. From the stream directed into decomposition zone, C₄- hydrocarbons are advantageously distilled off. Organic and/or aqueous streams isolated after decomposition are directed into additional conversion zone where additional amounts of isoprene are formed in presence of acid catalyst. A part of separated aqueous stream can be brought into contact with isobutylene-containing fraction in presence of acid catalyst to give tert-butanol, which is then directed as starting material into isoprene precursors' synthesis zone. EFFECT: enhanced process efficiency. 7 cl, 3 dwg, 1 tbl