Breaking a methanol/methyl methacrylate azeotrope using pressure swing distillation

Patent metadata

Field	Value
Publication number	US-10144698-B2
Application number	US-201515521798-A
Country	US
Kind code	B2
Filing date	Oct 2, 2015
Priority date	Oct 31, 2014
Publication date	Dec 4, 2018
Grant date	Dec 4, 2018

Abstract

A methanol/MMA azeotrope is broken or avoided by a method comprising the steps of (1) raising the pressure within a first vessel, e.g., a distillation column, that contains a methanol/MMA azeotrope, (2) collecting the azeotrope as a liquid, and then in a second, separate vessel, e.g., another distillation column, (3) raising the pressure sufficiently to allow for the breaking of or avoidance of the azeotrope and the recovery of the methanol.

First claim

What is claimed is:

1. A process for breaking or minimizing a methanol/methyl methacrylate (MMA) azeotrope, the process comprising the steps of:
(A) feeding a liquid stream comprising methanol and MMA to a first distillation column operated at a first pressure and equipped with a reboiler;
(B) separating the liquid stream within the first distillation column into a first distillation column overheads stream comprising a methanol/MMA azeotrope and a first distillation column bottoms stream;
(C) transferring the first distillation column overheads stream to a second distillation column operated at a second pressure, the operating pressure of the second distillation column greater than the operating pressure of the first distillation column;
(D) separating the first distillation column overheads stream within the second distillation column into a second distillation column overheads stream comprising an amount of methanol/MMA azeotrope that is less than the amount of methanol/MMA azeotrope in the first column overheads stream, and a second distillation column bottoms stream; and
(E) recovering at least a part of the second distillation column overheads stream.

2. The process of claim 1 further comprising the step of transferring heat from the second distillation column to the first distillation column by recycling at least a part of the second distillation column overheads stream to the reboiler of the first distillation column.

3. The process of claim 1 in which the methanol/MMA azeotrope is within a product stream of an MMA manufacturing process in which methacrolein and methanol are reacted.

4. The process of claim 1 in which the first distillation column operates at a ratio of pressure to the second distillation column of at least 1 to 5.

5. The process of claim 1 in which an azeotropic agent is not used.

6. The process of claim 1 in which an azeotropic agent is present in the second distillation column.

Assignees

• Dow Global Technologies Llc
• Rohm & Haas

Inventors

• Pendergast John G
• Worley William G
• Hoy Iv Stacy W
• Crosthwaite Jacob M

Classifications

• B01D3/143

  by two or more of a fractionation, separation or rectification step · CPC title

• B01D3/007

  Energy recuperation; Heat pumps · CPC title

• C07C29/82 Primary

  by azeotropic distillation · CPC title

• C07C69/54

  Acrylic acid esters; Methacrylic acid esters · CPC title

• C07C67/54 Primary

  by distillation · CPC title