Sulfole® 90 mercaptan is also known as tert-nonyl mercaptan. This product is a mixture of highly branched C9H19 alkyl mercaptan isomers, produced by the addition of hydrogen sulfide to propylene trimer. It is used as a chemical intermediate to introduce tertiary C9H19 alkyl-thio substituents into molecules. Another use is as a chain transfer agent to control molecular weight of polymeric systems undergoing free-radical polymerization.