PURPOSE: A mixture of the subject compd. of a large average particle size and is isomer 2-methacryloyloxy3-hydroxypropyltrimethylammonium chloride monomer.

CONSTITUTION: Methacrylic acid and epichlorhydrine are reacted in the presence of a catalytic amount of MAHTAC (the subject compd. and its isomer) at a temperature of 65-90°C for 5-7 hours and the reaction product is reacted with a trimethylamine in MAHTAC and a non-solvent to MAHTAC at a temperature of 55-70°C for 4-10 hours to obtain the subject compd. MAHTAC is recycled to the initial stage of the process as it is not only the final product but works as a catalyst and species enhancing the total reaction. The reaction is performed in the presence of a polymerization such as p-methoxyphenol. The obtain crystalline monomer has an average size of larger than 40 μ (especially 40-200 μ), a purity of more than 94% and useful for the production of water-soluble polymers having antistatic, coagulating and water processing properties.