An integrated combination isomerization and liquid phase adsorptive separation process for C₅ and C₆ hydrocarbons is given increased efficiency and cost effectiveness while also improving the product quality by eliminating the columns for the sepaation of desorbent material from extract and raffinate streams. In this arrangment a C₅+ naphtha stream (10) is split into a heavy hydrocarbon stream (14) comprising normal hexane and higher boiling hydrocarbons and an isomerization zone feedstream (18) comprising isohexane and lower boiling hydrocarbons. The heavy hydrocarbon stream (14) goes directly to a deisohexanizer column (16). The isomerization zone feedstream (18) is combined with the extract stream (20) from an adsorptive separation section (30) to form a combined feed (24). C₅ and C₆ hydrocarbons in the combined feed (24) are isomerized (26) and passed directly into the adsorption section (30). In the adsorption section (30) normal hydrocarbons are selectively adsorbed on an adsorbent material, and a raffinate stream (32) comprising desorbent and isoparaffins is passed to the deisohexanizer column (16). A desorbent stream (30) is recovered as a side cut from the deisohexanizer column and supplies the desorbent (40) for the adsorption section (30). Any desorbent (22) in excess of that required for the adsorption section is combined with the isomerization zone feed (18). The extract stream (20) that is combined with the isomerization zone feed (18), is recovered from adsorption section (30). A bottoms stream (38) comprising C₇ and higher boiling hydrocarbons is withdrawn from the bottom of the deisohexanizer column (16). A high octane isomerate (34) is taken overhead from the deisohexanizer as a product stream.
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