Efficient conversion of thiols to disulfides by 2,3-tetrapyridinoporphyarzinocobalt(III) catalyzed aerobic oxidation

PETR 146

Phillip D. Voegel, phillip.voegel@selu.edu and Jacob Shaffer. Department of Chemistry & Physics, Southeastern Louisiana University, SLU 10878, Hammond, LA 70402
Metal pyridinoporphyrazines and phthalocyanines have been known for some time catalysts for sweetening of petroleum products. Lack of solubility makes preparation of fixed bed reactors containing these catalysts difficult. To achieve efficient surface coverage, sulfate and carboxylic acid derivatized phthalocyanines have been synthesized. However, increased solubility in the aqueous alkaline solution causes the catalysts to leach from the reactor bed limiting the amount of time before the catalyst must be replenished. 2,3-tetrapyridinoporphyarzinocobalt(III) ([Co(2,3-TPyP)]) catalyzes the facile conversion of primary and secondary thiols such as 1-octanethiol and cyclohexyl mercaptan to their respective disulfides. GC/MS analysis of extracted aqueous alkaline solution following aerobic oxidation clearly demonstrates complete conversion of thiol to disulfide without additional products. [Co(2,3-TPyP)] has been electrodeposited onto the surface of a reticulated vitreous carbon electrode from DMSO and will be employed as a fixed bed reactor for aerobic oxidation of thiols under ambient temperature conditions with excess oxygen.