Method Of Producing Lower Alcohols From Glycerol

• US 20110040132A1
• Filed: 10/18/2010
• Published: 02/17/2011
• Est. Priority Date: 04/22/2002
• Status: Active Grant

• Current Assignee: Renewable Alternatives LLC, Curators of the University of Missouri (University of Missouri)
• Original Assignee: Curators of the University of Missouri (University of Missouri)
• Inventors: Sutterlin, William Rusty, Dasari, Mohanprasad, Suppes, Galen J.
• Granted Patent: US 7,943,805 B2
• Time in Patent Office: Days
• US Class Current: 568/862
• CPC Class Codes: C07C 29/145 with hydrogen or hydrogen-containing gases
• CPC Class Codes: C07C 29/60 by elimination of -OH groups, e.g. by dehydration C07C29/34 takes precedence
• CPC Class Codes: C07C 31/205 1,3-Propanediol; 1,2-Propanediol
• CPC Class Codes: C07C 45/52 by dehydration and rearrangement involving two hydroxy groups in the same molecule
• CPC Class Codes: C07C 49/17 containing hydroxy groups sugars C07H

Abstract

A reactive-separation process converts glycerin into lower alcohols, having boiling points less than 200° C., at high yields. Conversion of natural glycerin to propylene glycol through an acetol intermediate is achieved at temperatures from 150° to 250° C. at a pressure ranging from 1 and 25 bar. The preferred applications of the propylene glycol are as an antifreeze, deicing compound, or anti-icing compound. The preferred catalyst for this process in a copper-chromium powder.

Claims

1. A process for converting glycerol to propylene glycol with high selectivity, comprising the steps of:

heating a glycerol-containing feedstock material in presence of a catalyst that is capable of dehydrating glycerol at a temperature from 170°

C. to 270°

C. and a pressure from 0.2 to 25 atmospheres with hydrogen as a limiting reagent to prevent formation of propylene glycol such that there is resultant formation of acetol in the feedstock material;

liberating the acetol in vapor phase from the feedstock material; and

reacting the acetol in vapor phase with hydrogen in the presence of a catalyst that is capable of hydrogenating acetol at a hydrogen partial pressure ranging from 0.2 to 50 bars to form propylene glycol.

2. The process of claim 1, wherein the glycerol-containing feedstock used in the step of heating contains from 5% to 15% water by weight.

3. The process of claim 1, wherein the catalyst used in the step of heating is a heterogeneous catalyst selected from the group consisting of palladium, nickel, rhodium, copper, zinc, chromium and combinations thereof.

4. The process of claim 1, wherein the step of liberating the acetol includes stripping the acetol by the action of a gas.

5. The process of claim 4, wherein the gas is primarily hydrogen.

6. The process of claim 5, wherein the temperature used in the heating step ranges from 180°

C. to 220°

C.

7. The process of claim 6, wherein the pressure used in the heating step ranges from 5 to 18 atmospheres,

8. The process of claim 5, wherein the step of condensing occurs using a condenser operating at a temperature ranging from 25°

C. to 150°

C.

9. The process of claim 7, wherein the condenser operates at a temperature ranging from 25°

C. to 60°

C.

10. The process of claim 6, comprising a step of adding a hydrogen co-reagent to promote conversion of acetol to propylene glycol,

11. The process of claim 10, comprising a step of recycling unused hydrogen from the condenser back to the reaction mixture.

12. The process of claim 1, wherein the reaction time of the heating step ranges from 4 to 46 hours.

13. The process of claim 1, wherein the reaction time of the heating step ranges from 4 to 28 hours.