Desulfurization of mercaptans to hydrocarbons by carbon monoxide and water in the presence of cobalt carbonyl

Model studies of the desulfurization reactions on metal surfaces and in organometallic complexes

“…Binding of the thiirane in the higher coordination site led to weakening of the C-S bond and to formation of a second C-C bond, consistent with C-S bond weakening and formation of the C=C double bond upon adsorption. Similar results were also seen for the reaction of thietane on M0 (110).~* The third channel, molecular desorption, was also governed by the ring size and amount of ring strain. A fraction of the unstrained cyclic sulfides, tetrahydrothiophene and pentamethylene sulfide, molecularly desorb whereas 100% of the highly strained rings, thiirane and thietane, react.…”

“…Thiolate formation was reported for all cyclic sulfides studied, except for the C2 sulfide, thiirane. For example, ring opening of the highly strained C3 sulfide, thietane, led to propanethiolate formation on Mo ( 110). The propanethiolate intermediate then underwent competing C-S bond hydrogenolysis to form propane and C-S and C-H bond scission to form propene.…”

“…Oligomerization was also seen in the reaction of thiirane with an osmium cluster. 83 In contrast, no oligomerization was seen during the reaction of thietane on Mo- (110), where it is thought to bind in a polynuclear site.…”

Cobalt carbonyl catalyzed reaction of mercaptans with Schiff bases and carbon monoxide

“…However, thioesters of type RCOSCH2R1 are also formed, where CH2R1 arises from the Schiff base. It is interesting to note that aromatic hydrocarbons (2) are not detected in any of these reactions. While most of the R group of the thiol is generally accounted for in these reactions, the fate of some of the Schiff base -particularly the NR" portion -is unknown.…”

“…Benzylic mercaptans and thiophenols can be carbonylated to carboxylic esters, with concurrent desulfurization, by means of cobalt carbonyl in aqueous alcohol (1,2). However, if the latter reaction is conducted in the presence of a conjugated diene, then thioesters are formed in good yields.…”