Sodium allyl-sulphonate prodn. - from allyl chloride and aq. sodium sulphite soln., with pH control, useful as monomer

摘要

Prodn. of Na allysulphonate (I) comprises first adding a 10-40% excess of allyl chloride (II) to an aq. soln. of Na2-SO3 prewarmed to 33-70 degrees C. The reaction is then carried out with vigorous stirring at 1-2.3 bar and pH kept at 7-11 pref. 9-10 (by adding NaOH) until practically all the Na2-SO3 has been consumed. Pref. the Na2SO3 is satd., i.e. 28% for a starting temp of 33 degrees C to 23.5% for one of 70 degrees C. The starting temp. is pref. lower than the required reaction temp. and the necessary heat is supplied by the exothermic reaction; esp. the starting temp. is about 44 degrees C and the reaction temp. 50-60 degrees C. (I) is comonomer esp. for acrylonitrile. Highly conc. Na2SO3 solns. can be used so energy consumption during work up is reduced. Reaction is rapid and selectivity high with hydrolysis of (II) reduced to 0.3-1.4% depending on temp.