NOVELTY - Normal paraffin is isomerized in reaction zone (130) from which portion of effluent stream comprising branched paraffins, hydrocarbons and hydrogen chloride (HCl) is passed to product separation zone (140) to separate paraffin. Portion of recycle stream from zone (140) is passed to separation zone (160) comprising resin membrane with polymer repeating unit (I), to withdraw permeate stream comprising HCl.    USE - For recovery of halide such as hydrogen chloride from streams containing 1-7C hydrocarbons, especially used in the field of hydrocarbon processing for removing hydrogen chloride from light off gas or fuel gas streams in oil refineries.    ADVANTAGE - The sulfonated fluorinated polysulfone membranes are highly selective in permeating hydrogen from mixture of hydrogen and methane. Since the permeance of sulfonated fluorinated polysulfone membranes towards hydrocarbons decreases as the number of carbon atoms in hydrocarbon increases, the, polysulfone membranes are even more selective in permeating hydrogen chloride from a mixture of hydrocarbons that are heavier than methane.    DETAILED DESCRIPTION - Normal paraffin is introduced into isomerization reaction zone and isomerized into branched paraffins having same number of carbon atoms as normal paraffins in presence of chloride-containing catalyst. A reaction effluent stream comprising branched paraffins, 1-7C hydrocarbons and hydrogen chloride are recovered from isomerization reaction zone. A portion of reaction effluent stream is passed to product separation zone to separate the paraffin. A recycle stream comprising hydrogen chloride and hydrocarbons is withdrawn from the separation zone, and a portion of it is passed to membrane separation zone comprising a resin membrane comprising polymer or copolymer containing polymer repeating unit of formula (I). The permeate stream comprising hydrogen chloride is withdrawn from the membrane separation zone and branched paraffins are recovered.    S = sulfonic acid group or its salified form; and    m = average number of polymer repeating units in the polymer or copolymer having molecular weight of above 10000 and degree of substitution of S groups of 0.2-4.    DESCRIPTION OF DRAWING(S) - The figure shows the flow diagram of butane isomerization process.    Isomerization reaction zone (130)    Product separation zone (140)    Membrane separation zone (160)