METHOD FOR PRODUCING ISOPRENE Russian patent published in 1998 - IPC

FIELD: petrochemical synthesis, in particular, production of isoprene. SUBSTANCE: isoprene is produced by liquid-phase reaction of formaldehyde with isobutylene or with mixture of isobutylene with tert-butyl alcohol and/or methyl tert-butyl ether in water medium in the presence of acid, catalyst and inert organic solvent in two stages: at the first stage at temperature of 30-90 C, and at the second stage, at 110-145 C. Supplied to the first stage is isobutylene or its mixtures with tert-butyl alcohol and/or methyl tert-butyl ether, or their mixtures with isobutylene. Reagents are supplied to the reactors of the first and second stages by direct flow through mixers of rotary and/or static type. Reaction mixture after the second stage is separated into oil and water layers at 50-90 C. Oil layer is washed with water, then, solvent is separated and recirculated to the second stage, and isoprene is separated too. Water layer is evaporated in vacuum and recirculated to the first stage. EFFECT: higher isoprene yield, reduced corrosion of apparatuses and improved technical-and-economic indices of the process. 16 cl, 1 dwg