Patent ID: 9487469
Filing Date: 2016-11-08
CPC Classification: C07C

Claim Text:
1. A method for separating methyl methacrylate from a mixture containing said methyl methacrylate, methanol, and water comprising the steps of: providing said mixture to a first stage membrane unit in which said mixture is dehydrated, producing a dehydrated mixture containing said methyl methacrylate and said methanol; and providing said dehydrated mixture to a second stage membrane unit in which said methanol is removed from said dehydrated mixture, producing a permeate stream containing said methanol and a retentate stream containing in a range of about 95% to about 100 wt % said methyl methacrylate; wherein the first stage membrane unit comprises a small-pore hydrophilic membrane having a thickness of greater than about 20 μm and pore sizes of about 0.35 to about 0.45 nanometers selected from the group consisting of the following, and combinations thereof: a) Na b) Si c) microporous aluminophosphates; and the second stage membrane unit comprises a hydrophilic membrane having a faujasite structure.