Compounds of the structure R(SCH.sub.2 CHOHCH.sub.2 X).sub.n when n=1 to 4 and R is a hydrocarbon, ether, ester, acetal, hydroxy aliphatic, hydroxy aromatic, imide or amide group or halogenated derivatives thereof are prepared by reacting 1-halo-3-mercapto-2-propanol with an aliphatically unsaturated compound using free radical initiators as catalysts. The compounds in which R is an unsaturated or polyunsaturated aliphatic hydrocarbon group of 2 to 24 carbon atoms, or an unsaturated or polyunsaturated cycloaliphatic group, and those in which the aliphatic or cycloaliphatic group is connected through two or more of the polyunsaturated to two or more --S--CH.sub.2 CHOHCHCl groups, and compounds where R is an alkylene or polyalkylene substituted aromatic group and the hydroxy, thioalkyl, alkoxy, aryloxy, ester, carbamidoalkyl and sulfamidoalkyl, halogenated derivatives of said groups are new compounds. The thioether halohydrins can be converted to epoxides. The process utilizing a radioactive energy source as a catalyst is new.