TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Process: The isomerization of normal paraffin is carried out in presence of hydrogen. Both recycle stream and permeate stream comprises hydrogen. A portion of permeate stream is recycled to the isomerization reaction zone. The recycle stream is introduced to the non-permeate side of resin membrane, and non-permeate stream having a primary mole fraction of hydrogen chloride is recovered. The non-permeate side operates at non-permeate pressure. A permeate stream is recovered from permeate side of resin membrane, which operates at permeate pressure. A sweep stream having secondary mole fraction of hydrogen chloride is introduced to the permeate side of membrane. The product of secondary mole fraction and permeate pressure is not greater than the product of primary mole fraction and non-permeate pressure. The sweep stream comprises hydrocarbons which is same as normal paraffin or branched paraffin. The sweep stream is preferably withdrawn from the product separation zone. SPECIFIC COMPOUNDS - The normal paraffin is normal butane, normal pentane or normal hexane. The branched paraffin is isobutane, isopentane or 2,2-dimethylbutane or 2,3-dimethyl butane.    EXAMPLE - A membrane comprising polymer or copolymer containing polymer repeating unit (I) was tested for permeation of hydrogen chloride as follows. A feed comprising (in mol%) hydrogen chloride (5), hydrogen (10), methane (80) and propane (5) was passed to a micro module containing 6-fluorosulfonate polysulfone membrane which was maintained at constant temperature of 150 degrees F in a temperature controlled box. The feed was passed to the permeate side of micro module which was maintained at pressure of 100 psi(a), and a permeate stream was withdrawn from the permeate side of membrane. A portion of permeate was analyzed by gas chromatograph. The flow rates of feed, non-permeate, and permeate were measured by rotometers. The stage cut which was defined as volumetric flow rate of permeate divided by volumetric flow rate of feed times 100, was 1-3%. The micro module was maintained under the conditions for 201 hours. The selectivities of methane relative to propane, hydrogen relative to hydrogen chloride and hydrogen chloride relative to methane were measured and found to be 3-3.5, 1.2-2.5 and 60-90, respectively. The result showed that hydrogen chloride permeates through the membrane from 60-90 times faster than methane and even faster relative to propane. It was found that hydrocarbons heavier than propane permeate through the membrane even more slowly than propane, and therefore hydrogen chloride permeates much faster than all of the light hydrocarbons. The results also indicated that the permeability of hydrogen chloride is 40-83% of hydrogen, which was the component of feed that permeates most readily through the membrane.