Patent ID: 7939597

Claim:
A process for preparation of a polymer by polymerization of acrylic acid, comprising the following steps: A heating an aqueous glycerine solution before entry into a dehydration reactor to a temperature of from about 250° C. to 310° C. to form glycerine; B transporting the glycerine of step A to the dehydration reactor; C dehydrating the glycerine of step B to an acrolein-comprising dehydration product wherein the dehydrating occurs along a path wherein the glycerine concentration decreases, wherein along this path a pressure change occurs, and different flow rates exist; D gas phase oxidating of the acrolein-comprising dehydration product to obtain an acrylic acid-comprising monomer gas; E bringing into contact of the monomer gas with a quench agent to obtain an acrylic acid-comprising quench phase; F working-up the quench phase to obtain an acrylic acid-comprising monomer phase; and G polymerizing the acrylic acid-comprising monomer phase; wherein during the dehydration a liquid phase a1 and a gas phase a2 is present, wherein in the liquid phase a1, a plurality of gas bubbles is generated wherein the dehydration occurs at least partially in the liquid phase.