	US 12,110,269 B2
	Process for preparing dialkyl carbonate and alkanediol
Kai Jürgen Fischer, Amsterdam (NL); and Evert Van Der Heide, Amsterdam (NL)
Assigned to Shell USA, Inc., Houston, TX (US)
Appl. No. 17/311,826
Filed by SHELL OIL COMPANY, Houston, TX (US)
PCT Filed Dec. 16, 2019, PCT No. PCT/EP2019/085266 § 371(c)(1), (2) Date Jun. 8, 2021, PCT Pub. No. WO2020/126989, PCT Pub. Date Jun. 25, 2020.
Claims priority of application No. 18213317 (EP), filed on Dec. 18, 2018.
Prior Publication US 2022/0017450 A1, Jan. 20, 2022
Int. Cl. C07C 68/065 (2020.01); C07C 29/48 (2006.01); C07C 68/08 (2006.01)

CPC C07C 68/065 (2013.01) [C07C 68/08 (2013.01)]

9 Claims

1. A process for the preparation of a dialkyl carbonate and an alkanediol, comprising:

(a) reacting an alkylene carbonate and an alkanol to obtain a product mixture containing unconverted alkylene carbonate, unconverted alkanol, dialkyl carbonate, alkanediol and an ether alkanol impurity;

(b) separating unconverted alkylene carbonate and alkanediol from the product mixture to obtain a top stream containing unconverted alkanol, dialkyl carbonate and the ether alkanol impurity;

(d) separating unconverted alkanol from the top stream obtained in step (b) to obtain a bottom stream containing dialkyl carbonate and the ether alkanol impurity; and

(e) subjecting the bottom stream obtained in step (d) to extractive distillation using an extraction solvent to obtain a top stream comprising dialkyl carbonate and a bottom stream comprising the extraction solvent and the ether alkanol impurity, wherein the extraction solvent is an organic compound containing one or more hydroxyl groups and one or more ester moieties and/or ether moieties; and

(f) removing the ether alkanol impurity from the bottom stream obtained in step (e) and recycling the extraction solvent to step (e).