A scheme of an industrial process for preparing a solvent by fractional distillation and catalytic hydrofining of the C-5-C-7 fraction on a reactivated spent platinum-alumina isomerization catalyst was proposed for use in the manufacture of ethylene-propylene-diene rubbers. The process allows a high efficiency of removal of trace sulfur-containing, unsaturated, and aromatic compounds from the solvent to be attained and several desired products to be simultaneously obtained.