Sulfole® 120 mercaptan is a mixture of tertiary mercaptans, predominantly tertiary dodecyl mercaptan (thus the source for its acronym TDM). This product contains highly branched C12H25 alkyl mercaptan isomers, produced by the addition of hydrogen sulfide to propylene tetramer. It is used as a chemical intermediate to introduce bulky C12H25 alkyl-thio substituents into chemical substances. Its major use is as a chain transfer agent to control molecular weight of polymeric systems undergoing free-radical polymerization.