Method for purifying (meth)acrylic monomers by distillation
AssigneeArkema Inc.
InventorsMichel Fauconet, Stephane Lepizzera
Life of this patent
Estimating the term…
Abstract
The invention concerns a method of purifying a (meth) acrylic monomer selected among (meth) acrylic acids and their esters, by distillation in the presence of at least a polymerisation inhibitor requiring input of oxygen and/or an inhibitor having better efficacy in the presence of oxygen for stabilizing the liquid phase. The invention is characterized in that the distillation is performed in the presence of a NO2 gas, with an oxygen/organic vapor (p/p) ratio ranging between 0.02 and 3%, and with a NO2 condensed organic vapor (p/p) ratio ranging between 0.01 and 50 ppm.
Claims17
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 NO2, with an oxygen/organic vapor ratio (w/w) of between 0.0002 and 0.03, and with an NO2/organic vapor ratio (w/w) of between 0.01×10−6 and 50×10−6.
Dependencies are inferred from the claim text.