Process for purification of methyl methacrylate using molecular sieve membranes

Patent metadata

Field	Value
Publication number	US-9487469-B2
Application number	US-201313963677-A
Country	US
Kind code	B2
Filing date	Aug 9, 2013
Priority date	Aug 9, 2013
Publication date	Nov 8, 2016
Grant date	Nov 8, 2016

Abstract

A method for separating the components of a mixture containing methyl methacrylate, water, and methanol in which the mixture is dehydrated in a first stage membrane unit, producing a dehydrated mixture. Methanol in the dehydrated mixture is removed in a second stage membrane unit, producing a retentate stream containing methyl methacrylate and substantially no said methanol.

First claim

We claim:

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 12 Al 12 Si 12 O 48 •27H 2 O,
b) Si x Al y P z O 2 , where x=0.01-0.98, y=0.01-0.60, z=0.01-0.52,
c) microporous aluminophosphates; and
the second stage membrane unit comprises a hydrophilic membrane having a faujasite structure.

2. The method of claim 1 , wherein said dehydrated mixture is provided to a polishing adsorption column in which any remaining trace amounts of water are removed.

3. The method of claim 1 , wherein said first stage membrane unit comprises a hydrophilic zeolite A membrane.

4. The method of claim 1 , wherein said second stage membrane unit comprises a zeolite FAU membrane.

5. The method of claim 2 , wherein said polishing adsorption column contains a column packing material comprising 3A zeolites.

6. The method of claim 1 , wherein said methanol is recycled to a methyl methacrylate production process.

7. A method for separating the components of a mixture containing methyl methacrylate, water, and methanol comprising the steps of:
dehydrating said mixture in a first stage membrane unit, producing a dehydrated mixture; and removing said methanol from said dehydrated mixture in a second stage membrane unit, producing a retentate stream containing said methyl methacrylate and 5.0 wt % said methanol;
wherein the first stage membrane unit comprises a small-pore hydrophilic membrane having pore sizes of about 0.35 to about 0.45 nanometers selected from the group consisting of the following, and combinations thereof:
a) Na 12 Al 12 Si 12 O 48 •27H 2 O,
b) Si x Al y P z O 2 , where x=0.01-0.98, y=0.01-0.60, z=0.01-0.52,
c) microporous aluminophosphates; and
the second stage membrane unit comprises a hydrophilic membrane having a faujasite structure.

8. The method of claim 7 , wherein said first stage membrane unit comprises a hydrophilic zeolite A membrane.

9. The method of claim 7 , wherein said second stage membrane unit comprises a zeolite FAU membrane.

10. The method of claim 7 , wherein said dehydrated mixture is provided to a polishing adsorption column in which any remaining trace amounts of said water are removed.

11. The method of claim 10 , wherein said polishing adsorption column contains a column packing material comprising 3A zeolites.

12. The method of claim 7 , wherein at least a portion of said methanol removed from said dehydrated mixture is recycled for use in the production of said methyl methacrylate.

13. The method of claim 7 , wherein the small-pore hydrophilic membrane has a thickness of greater than about 20 μm.

Assignees

• Li Shiguang
• Zhou Shaojun
• Yu Miao
• Gas Tech Inst
• Univ Colorado Regents

Inventors

• Li Shiguang
• Zhou Shaojun
• Yu Miao

Classifications

• C07C67/56 Primary

  by solid-liquid treatment; by chemisorption · CPC title

• C07C69/54

  Acrylic acid esters; Methacrylic acid esters · CPC title