Abstract: Hydrogen 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.