Accession Number : AD0287737

Title :   THE ACID DISSOCIATION OF MERCAPTANS

Corporate Author : MINNESOTA UNIV MINNEAPOLIS

Personal Author(s) : KREEVOY,MAURICE M.

Report Date : 15 SEP 1961

Pagination or Media Count : 1

Abstract : A large number of acid dissociation constants of mercaptans were measured by one or two of three methods: pH titration, spectrophotometric determination using the UV absorption of the mercaptide ion, and gas solubility in neutral and basic solutions. For non-conjugated mercaptans other than H2S acid dissociation constants are correlated with high precision. Conjugated mercaptans (thiophenol and thiolacetic acid) are stronger than predicted by 1.3 powers of ten. This is attributed to resonance stabilization of the anion. No Baker-Nathan or resonance effects were found. The rate of proton abstraction from 2-mercaptoethanol by hydroxide ion and other bases was measured. The reaction is diffusion controlled in the case of OH ion but slower in the case of other bases. Proton recapture by the mercaptide is diffusion controlled if hydronium ion is the donor but not with other acids. Proton exchange is not measurably acid catalyzed. (Author)

Descriptors :   *THIOLS, DISSOCIATION, HYDROXIDES, IONS, PROTONS, SPECTROPHOTOMETERS, ULTRAVIOLET RADIATION

Distribution Statement : APPROVED FOR PUBLIC RELEASE