H2S removal from natural gas or from gases produced by the petroleum industry typically involves air oxidation of HS into elemental sulfur and water. The rate of the anthraquinone reduction and sulfur formation reaction in the first stage of the HysulfSM process was studied. Details of the 2-tert-butylanthraquinone (TBAQ) to H2TBAQ reaction mechanism were studied using cyclic voltammetry and an electrochemical cell. When the H2S concentration was maintained constant through out the test, the rate was dependant only on the TBAQ concentration and a plot typical of a first order reaction was obtained. Computational analysis and reaction data suggested that the initial step of the reaction requires the anthraquinone diradical and the formation of an HS- species. The formation of these species is necessary to provide a good match between the TBAQ LUMO and HS- HOMO energy levels. Solvent polarity was not the primary factor that affected the TBAQ conversion. The ability of the solvent to complex with the H2S and/or the TBAQ to alter their respective HOMO and LUMO energy levels might be a requirement. Tertiary amides, e.g., N-methyl-2-pyrrolidinone or N,N-dimethylacetamide, are better solvents for TBAQ reduction than secondary amides, cyclic ethers, alcohols, or lactones. This is an abstract of a paper presented at the ACS Fuel Chemistry Meeting (Washington, DC Fall 2005).