PROCESS FOR SEPARATING NORMAL AND ISOPARAFFINS

An improved process for separating normal paraffins from a feed stream containing a mixture of normal paraffins, isoparaffins and aromatic hydrocarbons to produce a normal paraffin product stream having a reduced concentration of contaminant aromatic hydrocarbons. The general process comprises the steps of contacting the feed stream with an adsorbent comprising a crystalline aluminosilicate wherein normal paraffins are adsorbed within the pores of the adsorbent and contaminant araomatics are adsorbed on the surface of the adsorbent and subsequently contacting the adsorbent with a desorbent material to remove both adsorbed normal paraffins and contaminant aramatics. The improvement resides in using a two-stage desorption step in which a first desorbent material contacts the adsorbent and removes surface-adsorbed aromatic contaminants and then a second desorbent material contacts the adsorbent to remove normal paraffins adsorbed within the pores of the adsorbent.