Process for the preparation of unsaturated quaternary ammonium salts

A process for preparing an unsaturated quaternary ammonium salt represented by the general formula (I):

• (CH.sub.2 .dbd.CR.sub.1 --COOCH.sub.2 CH.sub.2 NR.sub.2 R.sub.3 R.sub.4).sup.30 X.sup.-
• where R.sub.1 is --H or --CH.sub.3, R.sub.2 and R.sub.3 are --CH.sub.3 or --C.sub.2 H.sub.5, R.sub.4 is --CH.sub.3 or --C.sub.2 H.sub.5, and X is Cl, Br, or I, by reacting an unsaturated tertiary amine represented by the general formula (II):
• CH.sub.2 .dbd.CR.sub.1 --COOCH.sub.2 CH.sub.2 NR.sub.2 R.sub.3
• wherein R.sub.1, R.sub.2 and R.sub.3 are as defined above, with a halogenated hydrocarbon in an aqueous medium, characterized in that:
• (i) the reaction is carried out at a concentration of the unsaturated tertiary amine in the aqueous medium of 78 to 91% by weight to produce the unsaturated quaternary ammonium salt at a concentration in the aqueous medium of 82-93% by weight, and the reaction temperature is elevated so that it reaches 65.degree. to 90.degree. C. at the time of completion of the reaction and so controlled that no precipitation of the crystals of the unsaturated quaternary ammonium salt occurs and
• (ii) the reaction product solution obtained is cooled by attaching it, either immediately or after mixing with the reaction product solution which has already been cooled to a temperature lower than that of said reaction product solution, in the form of a thin film onto a cooled glass-lined or chromium-plated solid surface to precipitate the unsaturated quaternary ammonium salt crystals to form the desired slurry.