The S-H Frequency of the Mercaptans

Abstract

The spectra of one aromatic and two aliphatic mercaptans have been studied in the region between 2.75μ and 4.25μ. In addition to the bands near 3.3μ arising from the carbon-hydrogen linkage, absorption maxima were observed at 3.85μ in benzyl mercaptan, at 3.83μ in $n$-propyl mercaptan, and at 3.80μ in $n$-butyl mercaptan. These bands are attributed to a vibration of the S-H group. The data obtained in the present study are compared with the existing Raman data and with the infra-red bands arising from the O-H group.