A process for converting mixtures of C.sub.6 to C.sub.30 n-paraffin and n-paraffin by-products to substantially pure n-paraffin which comprises catalytically hydrogenating the mixture at a temperature of from about 600.degree. to 750.degree. F. in the presence of a Group VIII metal on alumina catalyst where the catalyst contains from about 0.05 to 2.0 weight percent of an alkali metal oxide or alkaline earth metal oxide or thallous oxide. The catalyst can additionally contain a Group VIB or VIIB metal.