METHOD FOR SYNTHESIS OF ISOBUTENE, ISOPRENE AND POSSIBLY TERTBUTANOL Russian patent published in 2010 - IPC C07C11/18 C07C11/09 C07C31/12 C07C1/24 C07C29/04 

FIELD: chemistry.

SUBSTANCE: invention relates to a method for synthesis of isobutene, isoprene and possibly tertbutanol from isobutene-containing C₄-fraction(s), involving hydration of isobutene in C₄-fraction(s), distillation of unreacted C₄-hydrocarbons from tert-butanol, dehydration of tert-butanol, bringing isobutene-containing C₄-fractions and possibly tert-butanol into contact with aqueous solution(s) of formaldehyde and acid, distillation of at least the remaining C₄-hydrocarbons and decomposition of intermediate products at high temperature with formation and subsequent extraction of isoprene and isobutene, characterised by that the initial isobutene-containing fraction(s) is at least partially hydrated on a sulfo-cation catalyst in a hydration unit with moderate supply of water in an amount which compensates for its consumption in the reaction with isobutene and output as part of an organic layer which mainly contains a mixture of unreacted C₄-hydrocarbons and tert-butanol formed during isobutene conversion ranging from 40 to 80%, a distillation stream mainly containing tert-butanol is extracted from at least part of the said organic layer, as well as a stream of unreacted C₄-hydrocarbons containing from 10 to 40% isobutene, which is brought into contact with aqueous solution(s) of formaldehyde and acid and intermediate products formed after distillation of at least the remaining C₄-hydrocarbons are subjected to liquid-phase or gas-phase catalytic decomposition at high temperature with formation of isoprene, isobutene and by-products, and the said stream which mainly contains tert-butanol is at least partially fed into the intermediate product decomposition zone directly and/or after coming into contact with at least aqueous solution(s) of formaldehyde and acid in an additional reaction zone, and the remaining part of the said stream which mainly contains tert-butanol is dehydrated to obtain isobutene.

EFFECT: use of the method reduces supply of water and associated power consumption.

8 cl, 1 dwg, 6 ex