The prohibition on use of tetraethyllead and the requirement of significantly reducing the aromatic hydrocarbon Content make it necessary to incorporate large quantities of branched C-5-C-6 paraffins in gasolines. These compounds can be obtained by isomerization of the corresponding linear paraffins, components of the stable condensate manufactured at gas processing plants (GPP). The skilled use and improvement of the properties of gas condensate are an important practical problem.