Compositions comprising branched C10 mercaptans selected from the group consisting of 5-methyl-1-mercapto-nonane, 3-propyl-1-mercapto-heptane, 4-ethyl-1-mercapto-octane, 2-butyl-1-mercapto-hexane, 5-methyl-2-mercapto-nonane, 3-propyl-2-mercapto-heptane, 4-ethyl-2-mercapto-octane, 5-methyl-5-mercapto-nonane, and combinations thereof. Compositions comprising C11+ mercaptans, wherein the C11+ mercaptans are characterized by structure R6—SH, wherein R6 is an alkyl group derived from one or more C11+ monoolefins, and wherein the one or more C11+ monoolefins comprise C11 internal monoolefins, C12 internal monoolefins, C13 internal monoolefins, C14 internal monoolefins, 1-tetradecene, 1-hexadecene, or combinations thereof. Compositions comprising branched C10+ mercaptans, wherein the branched C10+ mercaptans are characterized by structure R14—SH, wherein R14 is an alkyl group derived from one or more branched C10 to C30 monoolefins.