Abstract: A convenient method is reported for the preparation of piperazine phosphate, an anthelmintie and pharmaceutical intermediate. p-Toluenesulphonyl chloride, a by-product from saccharin manufacture, was first converted into p-toluenesulphonamide which was then condensed with ethylene dichloride in the presence of anhydrous potassium carbonate to form N,N'-bis-(p-toluenesulphonyl)-piperazine. Hydrolysis with concentrated phosphoric acid gave piperazine acid phosphate; the latter on partial neutralization with sodium or calcium hydroxide gave directly the expected' piperazine phosphate monohydrate, m.p. 224—6℃. Experimental conditions were studied.