2-mercaptobenzothiazole

2-Mercaptobenzothiazole is an organosulfur compound with the formula . A white solid, it is a reagent in organic synthesis and, notably, for the sulfur vulcanization of rubber.

==Structure== left|thumb|266x266px|Tautomers and deprotonated form of mercaptobenzothiazole The molecule is planar in shape, with a C=S double bond, so the name mercaptobenzothiazole is a misnomer; a more appropriate name could be benzothiazoline-2-thione. Solution measurements by NMR spectroscopy could not identify the presence of the thiol tautomer that the name implies, instead it exists as a thione/dithiocarbamate and the hydrogen appears on the nitrogen in the gas-phase, solid state, and in solution. Theory indicates that the thione tautomer is about 39 kJ/mol lower in energy than the thiol, and a hydrogen-bonded dimer of the thione has even lower energy. At alkaline pH greater than 7 the deprotonated thiolate form is most abundant. A protonated form could not be observed in the pH range 2-11.