Unsaturated quaternary ammonium salts preparation, for making cationic polymers for use as flocculating agents, comprises quaternization of N,N-dimethylaminoethylacrylate with methyl- or benzyl chloride in presence of water

摘要

A process for preparing unsaturated quaternary ammonium salts comprises quaternization of N,N-dimethylaminoethylacrylate with methyl- or benzyl chloride in the presence of water. A process for preparing aqueous solutions of unsaturated quaternary ammonium salts of formula (I) consists of reacting N,N-dimethylaminoethylacrylate (ADAME) with a quaternizing agent of formula R-Cl (II) in the presence of water. R = methyl or benzyl The process comprises: (a) charging 5-60 % of the total ADAME to a reactor, adjusting the air pressure in the reactor to 0.5-3 bars and conducting the reaction by introducing continuously at 35-65 deg C (II), water and the remaining ADAME until a solution containing the required concentration of the salt (I) in water is obtained, the reactants being introduced such that: (1) the introduction of water is commenced when 0-30 (10-20) wt. % of the total required amount of (II) has been introduced; (2) the introduction of the remaining ADAME is commenced when 20-80 (30-70) % of the total required amount of (II) has been introduced and (3) the pressure at the end of the reaction may reach 9 bars; then (b) releasing the pressure in the reactor whilst maintaining a constant level of oxygen by simultaneous introduction of air, then after returning to atmospheric pressure, eliminating residual quaternizing agent (II).