Process for preparing an 1,2-alkylene carbonate

Patent metadata

Field	Value
Publication number	US-2016108017-A1
Application number	US-201514953836-A
Country	US
Kind code	A1
Filing date	Nov 30, 2015
Priority date	Apr 23, 2007
Publication date	Apr 21, 2016
Grant date	—

Abstract

The invention relates to a process for preparing an 1,2-alkylene carbonate comprising
(i) contacting carbon dioxide, an 1,2-alkylene oxide and a carbonation catalyst in a reactor to produce a crude reactor effluent containing carbon dioxide, light components, 1,2-alkylene carbonate and catalyst; (ii) separating carbon dioxide and light components from the crude reactor effluent to form a bottoms stream containing 1,2-alkylene carbonate and catalyst; (iii) distilling the bottoms stream formed in step (ii) to form a first distillation overhead stream containing 1,2-alkylene carbonate and a first distillation bottoms stream containing catalyst, and recycling at least part of the first distillation bottoms stream to the reactor; and (iv) distilling the first distillation overhead stream to form a second distillation overhead stream and a second distillation bottoms stream containing 1,2-alkylene carbonate, and recycling at least part of the second distillation overhead stream to the reactor.

First claim

What is claimed is:

1 . A process for preparing an 1,2-alkylene carbonate comprising
(i) contacting carbon dioxide, an 1,2-alkylene oxide and a carbonation catalyst in a reactor to produce a crude reactor effluent containing carbon dioxide, light components, 1,2-alkylene carbonate and catalyst; (ii) separating carbon dioxide and light components from the crude reactor effluent to form a bottoms stream containing 1,2-alkylene carbonate and catalyst; (iii) distilling the bottoms stream formed in step (ii) to form a first distillation overhead stream containing 1,2-alkylene carbonate and a first distillation bottoms stream containing catalyst, and recycling at least part of the first distillation bottoms stream to the reactor; and (iv) distilling the first distillation overhead stream to form a second distillation overhead stream and a second distillation bottoms stream containing 1,2-alkylene carbonate, and recycling at least part of the second distillation overhead stream to the reactor.

2 . The process according to claim 1 , wherein an 1,2-alkylene diol is used as a solvent for the carbonation catalyst.

3 . The process according to claim 2 , wherein the first and second distillation overhead streams contain 1,2-alkylene diol.

4 . The process according to claim 3 , wherein at least part of the first distillation bottoms stream and at least part of the second distillation overhead stream are mixed prior to recycling to step (i).

5 . The process according to claim 1 , wherein at least part of the light components and/or carbon dioxide separated in step (ii) is recycled to the reactor.

6 . The process according to claim 1 , wherein an 1,2-alkylene carbonate is used as a solvent for the carbonation catalyst.

7 . A process according to claim 6 , wherein the first distillation bottoms stream contains part of 1,2-alkylene carbonate.

8 . The process according to claim 1 , wherein the carbonation catalyst comprises a tetra-alkylphosphonium bromide.

9 . The process according to claim 1 , wherein the 1,2-alkylene oxide is ethylene oxide and/or propylene oxide.

10 . The process according to claim 2 , wherein the 1,2-alkylene diol is monoethylene glycol and/or monopropylene glycol.

11 . The process according to claim 2 , wherein the 1,2-alkylene oxide is ethylene oxide and the 1,2-alkylene diol is monoethylene glycol.

12 . The process according to claim 2 , wherein the 1,2-alkylene oxide is propylene oxide and the 1,2-alkylene diol is monopropylene glycol.

13 . The process according to claim 1 , further comprising
(v) contacting at least part of the second distillation bottoms stream formed in step (iv) with an alkanol to obtain a reaction mixture containing an 1,2-alkylene diol and a dialkylcarbonate; and (vi) recovering 1,2-alkylene diol and dialkylcarbonate.

14 . The process according to claim 13 , wherein step (v) is performed in the presence of a heterogeneous transesterification catalyst.

15 . The process according to claim 13 , wherein the alkanol is methanol, ethanol or isopropanol.

Assignees

• Shell Oil Co

Inventors

• Nisbet Timothy Michael
• Vaporciyan Garo Garbis

Classifications

• B01J31/0268

  Phosphonium compounds, i.e. phosphine with an additional hydrogen or carbon atom bonded to phosphorous so as to result in a formal positive charge on phosphorous · CPC title

• C07D317/36 Primary

  Alkylene carbonates; Substituted alkylene carbonates · CPC title

• Y02P20/584

  Recycling of catalysts · CPC title