Preparation of alkenyl sulfonates

Claim 1

The process of neutralizing a sulfonation product mixture comprising alkenyl sulfonic acids wherein the alkenyl moiety is a propene or butene polymer having a number average molecular weight of about 250 to about 500 and sultones of said polymer with ammonia or sodium hydroxide, said sulfonation product mixture obtained by continuously treating a liquid propene or butene polymer having a number average molecular weight of about 250 to about 500 with gaseous sulfur trioxide which process comprises the steps of: first treating at atmospheric pressure said sulfonation product mixture at a temperature in the range of from about 100° to about 170°F with an amount of ammonia or aqueous sodium hydroxide sufficient to neutralize said sulfonic acid and provide a basic mixture comprising ammonium or sodium alkenyl sulfonates and said polymer sultones; and thereafter heating at atmospheric pressure said basic mixture to a temperature in the range of from about 290° to about 340°F to remove any water in said mixture and holding at atmospheric pressure, while maintaining the basicity of said mixture above pH 7, the anhydrous basic mixture at said temperature for a period of time sufficient to reduce the sultone content of said basic mixture and form additional alkenyl sulfonates whereby a liquid neutralized product mixture, substantially free of hydroxy alkyl sulfonates, comprising ammonium or sodium alkenyl sulfonates is obtained.