Method of producing lower alcohols from glycerol

• US 20050244312A1
• Filed: 03/24/2005
• Published: 11/03/2005
• 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 7,663,004 B2
• Time in Patent Office: Days
• US Class Current: 422/198
• 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:

combining a glycerol-containing feedstock that contains 50% or less by weight water with a catalyst that is capable of hydrogenating glycerol to form a reaction mixture; and

heating the reaction mixture to a temperature ranging from 150°

to 250°

C. over a reaction time interval ranging from 2 to 96 hours at a pressure ranging from 1 and 25 bar.

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

3. The process of claim 1, wherein the catalyst used in the step of combining 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, further comprising a step of removing reaction product vapors that form during the step of heating.

5. The process of claim 4, comprising a step of condensing the vapors to yield a liquid reaction product.

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.

14. A composition for use as an antifreeze, deicing agent, or anti-icing agent produced from the crude glycerol byproduct of the C₁ to C₄ alkyl alcohol alcoholysis of a glyceride comprised of:

on a water-free basis, from about 0.5% to about 60% glycerol, and from about 20% to about 85% propylene glycol.

15. The composition of claim 14 including

on a water-free basis, from about 10% to about 35% glycerol, from about 40% to about 75% propylene glycol, and from about 0.2% to about 10% C₁ to C₄ alkyl alcohol.

16. The antifreeze composition of claim 14 including from about 1% to 15% residue by-product from a reaction of glycerol.

17. A process for producing antifreeze from a crude glycerol byproduct of a C₁ to C₄ alkyl alcohol alcoholysis of a glyceride, comprising the steps of:

neutralizing the crude glycerol to achieve a pH between 5 and 12,

separating C₁ to C₄ alcohol and water from the crude glycerol such that the combined concentrations of water and C₁ to C₄ alcohols is less than about 5(wt) %; and

contacting the separated crude glycerol with a hydrogenation catalyst and hydrogen at a pressure of between about 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 the glycerol of between 60 and 90%.

18. The process according to claim 17, wherein the contacting pressure ranges from 1 to 20 bar.

19. The process according to claim 18 wherein separating the C₁ to C₄ alcohol and water is achieved by flash separation at a temperature greater than about 60°

C.

20. The process according to claim 17 wherein separating the C₁ to C₄ alcohol and water is achieved by thermal diffusion.

21. The process according to claim 17, including the further steps of:

neutralizing the glycerol with an adsorbent salt to form a substantially insoluble salt and

separating solid salts generated during neutralization from liquids.

22. The process according to claim 17 wherein said hydrogenation catalyst contains at least one metal from the group consisting of palladium, nickel, zinc, copper, platinum, rhodium, chromium, and ruthenium.

23. A process for converting glycerol to acetol with high selectivity, comprising the steps of:

combining a glycerol-containing feedstock with less than 50% by weight water with a catalyst that is capable of dehydrating glycerol to form a reaction mixture; and

heating the reaction mixture to a temperature ranging from 170°

to 270°

C. over a reaction time interval ranging from 0 to 24 hours at a pressure ranging from 0.2 and 25 bar.

24. The process of claim 23, wherein the glycerol-containing feedstock used in the step of combining contains from 0% to 15% water in glycerol by weight.

25. The process of claim 23, wherein the catalyst used in the step of combining is a heterogeneous catalyst selected from the group consisting of palladium, nickel, rhodium, copper, zinc, chromium and combinations thereof.

26. The process of claim 23, further comprising a step of removing reaction product vapors that form during the step of heating.

27. The process of claim 26, comprising a step of condensing the vapors to yield liquid reaction product.

28. The process of claim 27, wherein the temperature used in the heating step ranges from 180°

C. to 240°

C.

29. The process of claim 28, wherein the pressure used in the heating step ranges from 0.5 to 3 atmospheres,

30. The process of claim 27, wherein the step of condensing occurs using a condenser operating at a temperature ranging from 0°

C. to 140°

C.

31. The process of claim 30, wherein the condenser operates at a temperature ranging from 25°

C. to 60°

C.,

32. The process of claim 26, comprising a subsequent step of contacting the acetol with a hydrogen co-reagent to promote conversion of glycerol to propylene glycol,

33. The process of claim 32, comprising a step of recycling unused hydrogen from the condenser back to the subsequent step reaction mixture.

34. The process of claim 33, wherein the reaction time of the subsequent step reaction ranges from 0.2 to 24 hours.

35. The process of claim 34, wherein the reaction time of the subsequent step reaction ranges from 1 to 6 hours.

36. A process for converting a three-carbon or greater sugar or polysaccharide to an alcohol product having a boiling point less than 200 C, comprising the steps of:

combining a sugar or polysaccharide-containing feedstock with less than 50% by weight water with a catalyst that is capable of dehydrating glycerol to form a reaction mixture; and

heating the reaction mixture to a temperature ranging from 170°

to 270°

C. over a reaction time interval ranging from 0.5 to 24 hours at a pressure ranging from 0.2 and 25 bar.

37. The process according to claim 36 where the catalyst contains from 5 wt % to 95 wt % chromium.

38. The process according to claim 37 where the catalyst is comprised of compositions of copper expressed as CuO and chromium expressed as Cr₂O₃ at 30-80 wt % of CuO and 20-60 wt % of Cr₂O₃.

39. The process according to claim 37 where the catalyst compositions are expressed as Cr₂O₃ at 40-60 wt % of CuO and 40-50 wt % of Cr₂O₃.

40. The process according to claim 36 where the alcohol product is acetol.

41. The process according to claim 36 where the alcohol product is acrolein.

42. The process according to claim 36 where the alcohol product is a propanediol.

43. The process according to claim 36 where the alcohol product is removed as a vapor effluent and the reaction mixture is a liquid.

44. The process according to claim 43 where a gas feed enters the reactor and at least part of the gas exits the reactor in the vapor effluent.

45. The process according to claim 44 where the vapor effluent flows to a condenser and at least part of the alcohol product is condensed forming an alcohol condensate.

46. The process according to claim 45 where a vapor condensate effluent is in part comprised of the gas feed and the vapor condensate effluent is recycled to the reactor.

47. The process according to claim 45 where the alcohol condensate is reacted in a second reactor to form propanediol product.

48. In a liquid phase catalytic reaction process, the improvement comprising:

catalytically reacting an organic reagent that is distributed in the liquid phase to form a first product that has a boiling point of at least 20°

C. lower in temperature than does the reactant; and

removing the product by distillation and separation of product vapor as the reaction proceeds.

49. The process of claim 48, wherein the improvement further comprises condensing the product vapor to form a condensate and catalytically reacting the c condensate to form a second product.

50. The process of claim 48, wherein the step of catalytically reacting produces a residue that reduces the effectiveness of a catalyst facilitating the reaction, and further comprising hydrogen treatment of the catalyst to prolong the catalyst life by reduction of residue while the reaction is underway.

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

combining an acetol-containing feedstock with less than 50% by weight water with a catalyst that is capable of hydrogenating acetol to form a reaction mixture; and

heating the reaction mixture to a temperature ranging from 50°

to 250°

C. over a reaction time interval ranging from 0 to 24 hours at a pressure ranging from 1 and 25 bar.

52. The process of claim 51, wherein the acetol-containing feedstock used in the step of combining contains from 0% to 35% water in acetol by weight.

53. The process of claim 51, wherein the catalyst used in the step of combining is a heterogeneous catalyst selected from the group consisting of palladium, nickel, rhodium, copper, zinc, chromium and combinations thereof.

54. The process of claim 51, wherein the temperature used in the heating step ranges from 150°

C. to 220°

C.

55. The process of claim 51, wherein the pressure used in the heating step ranges from 10 to 20 bar.