Process for obtaining and product acrylic monomers useful in the preparation of cationic flocculants

Claim 1

A process for preparing a highly concentrated aqueous quaternary acrylic ester monomer solution which is directly polymerizable to form hard, transparent, water-soluble, high molecular weight cationic acrylic polymers and which comprises a major content of a salt of a monomeric compound of formula I ##STR2## wherein R represents hydrogen or methyl, A represents an alkylene group containing 1 to 3 carbon atoms, R 1 and R 2 are the same or different and each represents an alkyl group containing 1 to 4 carbon atoms, and R 3 represents a lower alkyl or benzyl group, said process comprising the steps of: (a) reacting an aqueous mixture containing about 50 to about 90% of a compound of formula II ##STR3## wherein R 1 , R 2 , R and A are as defined above, with a quaternizing agent of formula R 3 X, wherein R 3 is as defined above and X is halogen or the --CH 3 SO 4 group at a temperature of between about 10° and about 70° C. whereby a crude aqueous solution of a salt of a compound of formula I is obtained; (b) treating said crude aqueous solution with a water-insoluble solvent in order to obtain a mixture comprising a purified aqueous phase containing the salt of the compound of formula I and being substantially free of impurities of unreacted starting materials and of impurities which induce the formation of water-insoluble polymers, and an organic phase containing the water-insoluble solvent and said impurities; (c) separating the organic base of said mixture from the purified aqueous phase; and, (d) further purifying said purified aqueous phase and recovering therefrom a highly concentrated clear aqueous solution of the salt of the compound of formula I sufficiently free of said impurities and organic solvents said aqueous solution being directly polymerizable into a hard, transparent, water-soluble, high molecular weight cationic acrylic polymer.