Abstract
Ctalytic reduction of dithiodiglycolic acid was carried out with molybdenum sulfide catalyst at high pressure.The reaction was started at around 100°C with an initial pressure of hydrogen at 50 atm and gave thioglycolic acid as a main product.The maximum yield was 64.3% at 130°C but it was mixed with unreacted sample.Reduction to acetic acid was accompanied with an increase of temperature and nearly all was converted into acetic acid at 180°C.Comparison of the resul with that of general disulfides indicated that the cleavage of S-S bond of dithiodiglycolic acid was proceeded at low temperature and the mercapto group of thioglycolic acid formed also showed a tendency of cleavage to acetic acid the yield of thioglycolic acid was low for this reason. Comparison of result oi similar reduction of β-dithiodipropionic acid indicated that a characteristic reductive reaction of dithiodiglycolic acid was assumed to the effect of carboxy, group in α-position against the sulfur atom.
