Method of producing lower alcohols from glycerol

• US 9,404,027 B2
• Filed: 10/21/2013
• Issued: 08/02/2016
• Est. Priority Date: 04/22/2002
• Status: Active Grant

• Current Assignee: Curators of the University of Missouri (University of Missouri)
• Original Assignee: Curators of the University of Missouri (University of Missouri)
• Inventors: Suppes, Galen J.
• Primary Examiner(s): Price, Elvis O
• Application Number:
  US14/058,653
• Publication Number:
  US 20140042358A1
• Time in Patent Office: 1,016 Days
• Field of Search: 568/861
• US Class Current: 1/1
• CPC Class Codes: C07C 27/04 by reduction of oxygen-containing compounds C07C29/14 takes precedence
• 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 31/202 Ethylene glycol
• CPC Class Codes: C07C 31/205 1,3-Propanediol; 1,2-Propanediol
• CPC Class Codes: C07C 31/225 Glycerol
• 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
• CPC Class Codes: C09K 3/185 Thawing materials
• CPC Class Codes: C09K 5/10 Liquid materials
• CPC Class Codes: C09K 5/20 Antifreeze additives therefor, e.g. for radiator liquids for application to surfaces C09K3/18; inhibiting corrosion by liquids C23F11/00
• CPC Class Codes: Y02P 20/52 using catalysts, e.g. selective catalysts

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 pressures 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.

Claims

1. A process for producing antifreeze from a crude glycerol byproduct of either a C₁ to C₄ alkyl alcohol alcoholysis of a glyceride or hydrolysis of a glyceride, the process comprising:

neutralizing the crude glycerol byproduct to achieve a pH between 5 and 12 to form a neutralized crude glycerol byproduct;

separating C₁ to C₄ alcohol and water from the neutralized crude glycerol byproduct such that the combined concentrations of water and C₁ to C₄ alcohols is less than about 5 (wt) %, thereby forming a separated crude glycerol byproduct; and

contacting the separated crude glycerol byproduct with a hydrogenation catalyst and hydrogen at a pressure of between about 0.1 and 200 bar and at a temperature between about 100°

C. and 290°

C. for a period of time sufficient to achieve a conversion of glycerol of between 60 and 90% to form the antifreeze, which comprises, on a water-free basis, from about 0.5% to about 60% glycerol and from about 20% to about 85% propylene glycol.

2. The process according to claim 1, wherein the contacting pressure exists within a range from 1 to 20 bar.

3. The process according to claim 1 wherein the separating of C₁ to C₄ alcohol and water is achieved by flash separation at a temperature greater than about 60°

C. and less than 300°

C.

4. The process according to claim 1 wherein the separating of C₁ to C₄ alcohol and water is achieved by thermal diffusion.

5. The process according to claim 1, wherein the neutralizing comprises forming one or more substantially insoluble salt(s) and separating said insoluble salt(s) from the neutralized crude glycerol byproduct.

6. The process of claim 1, wherein the hydrogenation catalyst contains at least one element from Groups I or VIII of the Periodic Table.

7. The process according to claim 1 wherein the hydrogenation catalyst contains at least one metal from the group consisting of palladium, nickel, zinc, copper, platinum, rhodium, chromium, and ruthenium.

8. The process according to claim 1, wherein the neutralized crude glycerol byproduct has a pH that is from about 5 to about 9.

9. The process according to claim 1, wherein the crude glycerol byproduct comprises an acid catalyst of said C₁ to C₄ alkyl alcohol alcoholysis of a glyceride and the neutralizing comprises neutralizing said acid catalyst with a counter-ion to form a salt of the neutralized alcoholysis catalyst that is soluble in the neutralized crude glycerol byproduct.

10. The process according to claim 9, wherein, on a water-free basis, the glycerol content of the antifreeze is from about 10% to about 35% and the propylene content of the antifreeze is from about 40% to about 75%, and the antifreeze further comprises, on a water-free basis, from about 0.2% to about 10% C₁ to C₄ alkyl alcohol and from about 0.2% to about 5% of the salt of the neutralized alcoholysis catalyst.

11. The process according to claim 10 further comprising adding residue by-products of glycerol conversion reactions to the antifreeze, wherein said residue by-products are soluble in the antifreeze and constitute, on a water-free basis, from about 1% to about 15% of the antifreeze.