METHOD OF PREPARING ALKYLBENZENE Russian patent published in 1999 - IPC

FIELD: oil refining and petrochemical industries. SUBSTANCE: propane, isobutane and n-propane fractions are recovered from liquefied saturated petroleum gas. Propane-propylene and butane-butylene fractions are recovered from liquified unsaturated petroleum gas. Propane fraction containing 75% by volume of propane is subjected to separation at pressure of 1.3-1.5 MPa and at top temperature of 38-45 C and bottom temperature of 65-75 C to obtain in column still isobutane-containing fraction containing at least 75% by volume of isobutane is mixed with isobutane fraction containing at least 90% by volume of isobutane and is directed to reactor unit of sulfuric acid alkylation set-up. Isobutane fraction is alkylated with butane-butylene fraction in the presence of concentrated sulfuric acid continuously fed into reactor with spent sulfuric acid withdrawn for regeneration at isobutane to olefin volumetric ratio of at least 5:1 in stream flowing into reactor at temperature from 2 to 7 C. EFFECT: increased yield of alkylbenzene. 2 cl, 4 ex, 1 tbl