Summary In the reaction of propylene with sulfuric acid, no primary ester is formed. Peroxides do not cause the formation of primary normal amyl hydrogen sulfate from pentene- 1. The addition of sulfuric acid, using 85-90% acid to propylene and pentene-1, differs from the addition of hydrogen bromide in forming no primary derivatives. The addition of sulfuric acid to pentene-2 gives sulfuric esters of both pentanol-2 and pentanol-3.