A gas treating process is disclosed. Hydrogen sulfide and carbon dioxide are removed from a hydrocarbon vapor stream by absorption into an aqueous carbonate solution. Hydrogen sulfide picked up by the circulating carbonate solution is oxidized to produce liquid sulfur, which is withdrawn. The carbonate solution is then stripped to release carbon dioxide and produce the lean carbonate solution used for absorption. By-product thiosulfate formed in the oxidation step is eliminated by reaction with hydrogen sulfide. Metal phthalocyanines are used as the catalyst for the elimination of thiosulfate and for the oxidation of hydrogen sulfide.