HF Alkylation process

In a process for the acid-catalyzed alkylation of an isoparaffin with an olefin alkylating agent wherein the hydrocarbon phase of the alkylation reaction mixture comprising alkylate, unreacted isoparaffin and at least trace amounts of acid, and field paraffins comprising isoparaffins, n-paraffins and olefins, are introduced into a common fractionation column wherein said alkylate, n-paraffins and isoparaffins are separated at conditions conducive to olefin polymerization, the improvement which comprises:

• (a) initially treating said field paraffins in contact with a siliceous material effecting the separation of said olefins from said field paraffins;
• and,
• (b) thereafter introducing said field paraffins into said common fractionation column together with said hydrocarbon phase of said alkylation reaction mixture.