REMOVAL OF HYDROGEN SULPHIDE

PCT No. PCT/GB92/01328 Sec. 371 Date Apr. 14, 1994 Sec. 102(e) Date Apr. 14, 1994 PCT Filed Jul. 20, 1992 PCT Pub. No. WO93/02961 PCT Pub. Date Feb. 18, 1993Hydrogen sulphide can be removed from a gaseous stream by contact with a 2,3-dialkyl substituted naphthoquinone in the presence of a catalytic amount of an amine catalyst dissolved in a hydrophobic organic solvent system, with consequential formation of a corresponding quinhydrone and insoluble elemental sulphur. Preferably the total number of carbons in the alkyl substituents is from 2 to 6. Particularly suitable compounds comprise dimethyl and/or ethyl/methyl naphthoquinones. Preferably the amine catalyst has a pK in the range of about 9 to 11.5. Preferred solvent systems comprise mixtures of aromatic hydrocarbons with aliphatic esters such as methyl cyclohexanol acetate or dialkylketones such as diisobutylcarbinol. Advantageously, the naphthoquinone react with hydrogen sulphide significantly faster than do the anthraquinone or tetrahydroanthraquinone compounds hitherto proposed. The insoluble sulphur can be recovered as product and the resultant solution containing a reduced species, believed to be naphthoquinhydrone, can be contacted with an oxygen-containing gas for generation of hydrogen peroxide and reformation of the naphthoquinone. After extraction of the hydrogen peroxide with water, the organic solution is available for contact with further hydrogen sulphide.