US 4,091,046 AGranted

Production of isoprene from isobutane

AssigneePhillips Petroleum Company

InventorRolland E. Dixon

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Abstract

Isoamylene is produced from isobutane by cracking isobutane, separating a propylene stream and an isobutylene stream from the cracked product, disproportionating the propylene and isobutylene and separating an isoamylene stream from the disproportionated stream. The isoamylene can be converted into isoprene by dehydrogenation. The isobutane can be produced from normal butane by skeletal isomerization. The ethylene produced during the disproportionation can be dimerized and the butylenes obtained can be either reintroduced into the disproportionation reaction or can be dehydrogenated to butadiene. Isobutane removed from the cracked product, as well as isobutane removed from the disproportionated stream, is recycled into the cracking reaction. Hydrogen produced during the cracking reaction can be used either in the isomerization step for converting normal butane to isobutane, or can be used for hydrogenation of acetylenes produced during the conversion of the normal butene to butadiene.

Claims5

Dependent claims

A process for producing isoprene comprising

a. introducing isobutane into a cracking zone and cracking isobutane in said cracking zone,
b. withdrawing a cracked effluent comprising isobutylene, propylene and isobutane from said cracking zone,
c. introducing said cracked effluent into a first separation zone,
d. withdrawing a propylene stream and an isobutylene stream from said first separation zone,
e. introducing said propylene stream and said isobutylene stream into a disproportionation zone and disproportionating said streams in said disproportionation zone to form isoamylene,
f. withdrawing an effluent from said disproportionation zone,
g. introducing said disproportionated effluent into a second separation zone,
h. withdrawing an ethylene-comprising stream from said second separation zone,
i. passing said ethylene-comprising stream to a dimerization zone and converting ethylene of said ethylene-comprising stream to butylenes,
j. introducing at least a portion of said butylenes into an isomerization zone in which 1-butylene is isomerized into 2-butylene and wherein at least a portion of the butylenes from said isomerization zone are introduced into said disproportiontion zone,
k. withdrawing an isoamylene-comprising stream from said second separation zone, and
l. dehydrogenating isoamylene from said isoamylene-comprising stream in a first dehydrogenation zone to produce isoprene.

9 more elements

Dependencies are inferred from the claim text.