| 摘要 |
<p>Process for preparing aqueous solutions of unsaturated quaternary ammonium salts in accordance with formula H2C=C(R3)-C(O)-A-R4-N<+>(R1)(R2)(R), X<-> from at least one (meth)acrylic monomer (II) having the formula H2C=C(R3)-C(O)-A-R4-N(R1)(R2) and from at least one quaternizing agent (III) having formula RX, in the presence of at least one polymerization inhibitor. Said process is characterized in that the reaction is performed at a temperature between 10 DEG C and 80 DEG C, in that (a) in a first stage all or part of the quaternizing agent (3) required for the reaction is introduced in the reactor, said agent (2) being in a liquid state in the reaction conditions, (b) at least one (meth)acrylic monomer (II) is added, and (c) as soon as between 0 and 30 % of the stoichiometry of the (meth)acrylic monomer(s) has been introduced in the reactor, the remainder of the quaternizing agent (III) is added continuously and simultaneously, the remainder of the (meth)acrylic monomers and water until the desired concentration of unsaturated quaternary ammonium salts (I) is obtained, (d) and in the event that the quaternizing agent (III) is in the gaseous state at the reaction temperature, the reaction is effected in the presence of oxygen and a pressure is imposed so that the quaternizing agent is in the liquid state, and at the end of the reaction, the pressure is progressively reduced to atmospheric pressure, and simultaneously a ratio is established between the total gas volume flow at the output of the reactor and the volume flow of the oxygen introduced in the reactor, said ratio being less than 100.</p> |
