Branched chain hydrocarbons, which are in vapor state under hydrogenation conditions, are added to the H2 and C oxide. Isobutane, isobutylene, isopentane, the methylbutenes and methylpentenes, 2,2-dimethylbutane, and 2,3-dimethylbutane are examples of hydrocarbons of the preferred volatility range. A mixture may be used, but recycling of the unreacted branch-chain hydrocarbon in substantial absence of straight- chain hydrocarbons is simplified if only a single branched hydrocarbon has been used. It is believed that the branched-chain hydrocarbon reacts with the methylene radicals at the catalyst surface to produce branched chain hydrocarbons of higher molecular weight rather than essentially straight chain hydrocarbons such as are produced from CO and H2 alone. It is desirable to use at least 5 mol. percent of isobutane, based on the C oxide in the reaction mixture and corresponding amounts of other branched chain hydrocarbons amounts of 5-15 mol. percent are suitable for obtaining a substantially modified reaction product. However, a large excess of the branched-chain hydrocarbons, such as, 100-1,000 mol. percent may be used to minimize the formation of the usual C oxide hydrogenation products. The usual hydrogenation procedure is used.
PEXTON, S. See abs. 912.