Abstract: The present invention provides a process for the preparation of 5-(4'-chloro-5'-sulfamoyl-2'-thenylamino)-phenyltetrazole by condensing 5-(4'-chloro-5'-sulfamoyl-2'-aminophenyl)-tetrazole with thiophene-2-aldehyde in the presence of an acid catalyst and reducing the 5-[4'-chloro-5'-sulfamoyl-2'-(thenylidene-2-amino)-phenyl]tetrazole so obtained with a boranate, wherein the condensation is carried out in dimethyl sulfoxide as solvent, with azeotropic distilling off of the water formed and the reduction is carried out in the same medium, without isolation of the 5-[4'-chloro-5'-sulfamoyl-2'-(thenylidene-2-amino)-phenyl]-tetrazole.

Abstract: The process for the chromatographic fractionation of whey comprising passing whey through a column of an ion exchange material, thereafter passing water through said column as eluant, and collecting the aqueous effluent from said column as a plurality of fractions. Advantageously the ion exchange material is a polystyrene resin containing sulfonic acid groups neutralized with calcium ions and cross-linked with about 2 to 4% by weight of divinyl-benzene, and the eluant is demineralized water.