Patent ID: 7029556
Filing Date: 2006-04-18
Classification: C07C

Abstract:
1. A process for purifying a (meth)acrylic monomer selected from the group consisting of (meth)acrylic acids and esters thereof, comprising conducting distillation in the presence of at least one polymerization inhibitor requiring an introduction of oxygen and/or an inhibitor exhibiting better efficacy in the presence of oxygen for the stabilization of resultant liquid phase, the improvement comprising conducting the distillation in a distillation column in the presence of introduced gaseous NO 2 , with an oxygen/organic vapor ratio (w/w) of between 0.0002 and 0.03, and with an NO 2 /organic vapor ratio (w/w) of between 0.01×10 −6 and 50×10 −6 .