METHOD OF ISOPRENE PRODUCTION Russian patent published in 1997 - IPC

FIELD: rubber industry. SUBSTANCE: isoprene is produced by way of liquid-phase interaction of formaldehyde with isobutylene and/or trimethylcarbinol in presence of aqueous solution of acid catalyst at elevated temperature and pressure in two consecutive reaction zones, in the first of which process is carried out at 80-110 C and pressure 15-20 atm and in the second one, respectively, 125-170 C and 5-15 atm taking off water from the top of second-zone reactor in amount 30-65% based on weight of water fed into the first reaction zone. From the top of the second reaction zone, isoprene-containing reaction products are also taken off. Reactor of the first reaction zone may constitute one or several hollow apparatuses, whereas in the second reaction zone, reaction- separation apparatus may be utilized. With successive connection of first-zone reactors, reaction mixture after each of them but the last can be cooled to temperature by 5-15 C lower than that on outlet of the next reactor. Reaction mixture, prior to be fed into second-zone reactor, may be heated to temperature of its introduction point. EFFECT: enhanced efficiency of process. 5 cl, 1 tbl