| abstract |
The invention relates to an improved process for the preparation of metal phthalocyanine sulfonamide catalysts of the formula MPc (SO2 NHR) x useful for sweetening LPG and light petroleum distillates, comprising reacting a metal phthalocyanine. with chlorosulfonic acid at a certain temperature, cooling the mixture by adding 1 to 7 parts of a chloride-type reagent, heating said mixture to obtain the sulfonyl chloride of metal phthalocyanine, isolating said compound by adding the reaction mixture to ice water, reacting the sulfonyl chloride of the isolated metal phthalocyanine with an amine of the general formula H2 NR where R is selected from a hydrogen atom, an aryl group, an alkyl group, and cycloalkyl, in an aqueous or non-aqueous medium or in a mixture thereof, at a certain temperature, in the presence of an acid binding agent, to obtain the desired catalyst. |