Method of producing lower alcohols from glycerol

• US 20080315151A1
• Filed: 08/28/2006
• Published: 12/25/2008
• 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, Suppes, Galen J.
• Granted Patent: US 8,017,816 B2
• Time in Patent Office: Days
• US Class Current: 252/73
• 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
• 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: C12C 11/02 Pitching yeast

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 converting glycerol to acetol with high selectivity, comprising the steps of:

contacting a glycerol-containing material with a catalyst that is capable of hydrogenating glycerol, in order to form a reaction mixture; and

establishing conditions for reaction of the reaction mixture that include a temperature within a range from 150°

C. to 250°

C. and a pressure within a range from 0.02 bar to 25 bar, and

reacting the reaction mixture under the conditions for reaction to dehydrate the glycerol with resultant formation of acetol as a reaction product.

2. The process of claim 1, wherein the glycerol-containing feedstock used in the step of providing contains from 0% to 50% water by weight.

3. The process of claim 1, wherein the catalyst used in the step of contacting contains at least one element from Groups I or VIII of the Periodic Table.

4. The process of claim 1, wherein the catalyst used in the step of contacting is a heterogeneous catalyst including at least one material selected from the group consisting of palladium, nickel, rhodium, copper, zinc, chromium and combinations thereof.

5. The process of claim 1, wherein the pressure condition for reaction used in the step of reacting includes maintaining a partial pressure of hydrogen that is effective to deter the acetol reaction product during formation from scavenging hydrogen from other hydrocarbon materials in the reaction mixture.

6. The process of claim 5, wherein the partial pressure of hydrogen sufficiently low to prevent substantial conversion of acetol to propylene glycol.

7. The process of claim 6 wherein the partial pressure of hydrogen is less than about 0.1 bar.

8. The process of claim 1, wherein the glycerol-containing material is in liquid phase and further comprising a step of removing reaction product during the step of reacting, in order to separate the acetol reaction product from the reaction mixture.

9. The process of claim 8, wherein the step of removing reaction product includes facilitating selective release of acetol as vapor from the reaction mixture by action of partial pressure through contact with a gas that is essentially inert to the reaction mixture and the acetol reaction product.

10. The process of claim 9, wherein the gas includes nitrogen.

11. The process of claim 9 including a step of condensing the acetol reaction product from the gas to form liquid acetol.

12. The process of claim 11, wherein the step of condensing occurs in a first condenser that operates at a temperature within a range from 25°

C. to 150°

C.

13. The process of claim 12, wherein the first condenser operates at a temperature within a range from 25°

C. to 60°

C.

14. The process of claim 11, further comprising a step of using the liquid acetol as an intermediate by further reacting the acetol to form a second reaction product.

15. The process of claim 14, wherein the step of further reacting includes introducing a hydrogen-containing gas to the liquid acetol at sufficient partial pressure for catalyzed reaction with the acetol to form propylene glycol as the second reaction product.

16. The process of claim 15, further comprising a step of removing the propylene glycol from the liquid by action of the gas under conditions of partial pressure that facilitate selective removal of propylene glycol.

17. The process of claim 16, further comprising a step of condensing the propylene glycol from the gas in a second condenser to provide liquid propylene glycol

18. The process of claim 17, wherein the step of further reacting yields unused hydrogen and further comprising a step of recycling the unused hydrogen back to the liquid acetol.

19. The process of claim 8, wherein the step of removing reaction product vapors includes facilitating release of reaction product as vapor from the reaction mixture by contact with a gas that is further reactive with the acetol reaction product.

20. The process of claim 19, further comprising a step of catalytically reacting the gas with the acetol reaction product to form a second reaction product.

21. The process of claim 20, wherein the gas includes hydrogen.

22. The process of claim 21, wherein the step of catalytically reacting includes reacting the hydrogen with the acetol reaction product to form propylene glycol.

23. The process of claim 1, further comprising contacting the reaction mixture with hydrogen at sufficient partial pressure of hydrogen to further react the acetol with the hydrogen for resultant formation of propylene glycol by hydrogenation

24. The process of claim 1, wherein the temperature condition of the reacting step exists within a range from 180°

C. to 220°

C.

25. The process of claim 24, wherein the pressure condition of the heating step exists within a range from 1.0 to 18 bar.

26. The process of claim 1, further comprising a step of adding a hydrogen co-reagent to promote conversion of acetol to a propylene glycol reaction product, with flow of gas including the hydrogen to strip propylene glycol reaction product from the reaction mixture.

27. The process of claim 26, comprising a step of condensing liquid propylene glycol from the gas by use of a condenser and recycling unused hydrogen from the condenser back to the reaction mixture.

28. The process of claim 1, wherein the reaction time of the reacting step persists for a duration within a range from 0.001 hour to 8 hours.

29. The process of claim 1, wherein the reaction time of the heating step exists within a range from 0.002 to 1 hours.

30. The process of claim 1, wherein the reaction time of the heating step exists within a range from 0.05 to 0.5 hours.

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

32. The composition of claim 31 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.

33. The antifreeze composition of claim 32 including from about 1% to 15% residue by-product from a reaction of glycerol.

34. 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, 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) %;

contacting the separated crude glycerol 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 the glycerol of between 60 and 90%.

35. The process according to claim 34, wherein the contacting pressure exists within a range from 1 to 20 bar.

36. The process according to claim 34 wherein the separating of C₁ to C₄ alcohol and water is achieved by flash separation at a temperature greater than about 60°

C.

37. The process according to claim 34 wherein the separating of C₁ to C₄ alcohol and water is achieved by thermal diffusion.

38. The process according to claim 34, 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.

39. The process of claim 34, wherein the hydrogenation catalyst used in the step of contacting contains at least one element from Groups I or VIII of the Periodic Table.

40. The process according to claim 34 wherein the hydrogenation catalyst contains at least one metal from the group consisting of palladium, nickel, zinc, copper, platinum, rhodium, chromium, and ruthenium.

41. A process for reacting a three-carbon or greater sugar or polysaccharide to form an alcohol product having a boiling point less than 200°

C., comprising the steps of;

contacting a polyhydric feedstock with a catalyst, where the polyhydric feedstock contains at least one of glycerol, sugar and polysaccharide material, in order to form a reaction mixture; and

heating the reaction mixture to a temperature in a range from 150°

C. to 270°

C. at a pressure within in a range from 0.02 to 25 bar to with resultant alcohol product formation.

42. The process of claim 41, wherein the dehydration catalyst used in the step of contacting contains at least one element from Groups I or VIII of the Periodic Table.

43. The process according to claim 42 wherein the dehydration catalyst contains from 5 wt % to 95 wt % chromium.

44. The process according to claim 43 where the dehydration catalyst is comprised of reduced forms of compositions of copper expressed as CuO and chromium expressed as Cr₂O₃ at 30-80 wt % of CuO and 20-60 wt % of Cr₂O₃.

45. The process according to claim 44 where the dehydration catalyst compositions are expressed as Cr₂O₃ at 40-60 wt % of CuO and 40-50 wt % of Cr₂O₃.

46. The process according to claim 41 including a step of selecting the feedstock to yield the alcohol product as acetol.

47. The process according to claim 41 including a step of selecting the feedstock to yield the alcohol product as a propanediol.

48. The process according to claim 41 including a step of selecting the feedstock to yield the alcohol product as a glycol.

49. The process according to claim 41 the reaction mixture is in liquid phase containing less than 50 wt % water and including a step of removing the alcohol product from the reaction mixture as a vapor effluent.

50. The process according to claim 49 wherein the step of removing the alcohol product entails feeding a gas to a reactor that contains the reaction mixture for stripping of the reaction product from the reaction mixture as vapor effluent and removing at least part of the gas together with the vapor effluent from the reactor.

51. The process according to claim 50 including a step of condensing at least part of the alcohol product from the gas to form an alcohol condensate.

52. The process according to claim 51 wherein a vapor condensate effluent is in part comprised of the gas feed and the vapor condensate effluent is recycled to the reactor.

53. The process according to claim 52 where the alcohol condensate is reacted in a second reactor to form a propanediol product.

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

55. The process of claim 54, wherein the improvement further comprises condensing the product vapor to form a condensate and catalytically reacting the condensate to form a second product.

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

contacting an acetol-containing feedstock that contains 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 between 50°

to 250°

C. at a pressure between 1 and 500 bar to form propylene glycol.

57. The process of claim 56, wherein the catalyst used in the step of combining contains at least one element from Groups I or VII of the Periodic Table.

58. The process of claim 56, wherein the acetol-containing feedstock used in the step of combining contains from 0% to 35% water in acetol by weight.

59. The process of claim 56, 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.

60. The process of claim 56, wherein the temperature used in the heating step exists within a range from 150°

C. to 220°

C.

61. The process of claim 56, wherein the pressure during the reaction is greater than 25 bar and acetol is present in a liquid phase.

62. The process of claim 56, wherein the acetol-containing feedstock is produced from a process operated at a pressure less than 5 bars.

63. The process of claim 62, wherein the reactor is of a type selected from the group including slurry batch reactor, trickle bed reactor, and teabag reactor.

64. A process for converting glycerol to a product at high selectivity to propylene glycol and low selectivity to ethylene glycol, comprising:

providing a gas phase reaction mixture that is essentially free of liquid and contains

glycerol with a partial pressure of glycerol in a range from 0.01 bars and 0.5 bars of glycerol, and

hydrogen with a partial pressure of hydrogen between 0.01 and 25 bars of hydrogen,

the reaction mixture being maintained at a total pressure between 0.02 and 25 bars; and

contacting the gas phase reaction mixture with a heterogeneous catalyst at a temperature between 150°

C. and 280°

C. to form propylene glycol.

65. The process of claim 64, wherein the heterogeneous catalyst used in the step of contacting contains at least one element from Groups I, VI, and VIII of the Periodic Table.

66. The process of claim 64, wherein the heterogeneous catalyst used in the step of reacting contains at least one metal selected from the group consisting of copper and chromium.

67. The process of claim 66, wherein the heterogeneous catalyst is a copper chromite catalyst.

68. The process of claim 64, wherein the temperature of the contacting step is within a range from 180°

C. to 240°

C.

69. The process of claim 64, wherein the pressure of the contacting step is within a range from 1 bar to 10 bars.

70. The process of claim 64, wherein a reaction product formed from the reaction mixture contains acetol.

71. The process of claim 70, wherein acetol is removed from the reaction product and recycled to form a mixture with the glycerol feed.

72. The process of claim 64 including a step of contacting a glycerol containing feed with a gas in an evaporating step at a temperature between 150°

C. and 280°

C. to evaporate glycerol to form a reactor feed.

73. The process of claim 72 wherein the contacting of glycerol with the gas occurs at a temperature within a range from 200°

C. to 260°

C.

74. The process of claim 73 wherein the temperature range is from 210°

C. to 230°

C.

75. The process of claim 72 wherein the glycerol feed contains a non-volatile salt and the evaporating step partially separates the non-volatile salt from the glycerol.

76. The process of claim 72 including the step of recycling the gas through a condenser that separates the reaction product from the gas.

77. The process of claim 64 wherein reaction conditions of the contacting step include a partial pressure of glycerol being

less than glycerol'"'"'s dew point partial pressure in the reaction mixture,

and greater than one fourth the dew point partial pressure in the reaction mixture.

78. The process of claim 77 wherein the partial pressure of glycerol is greater than half the dew point partial pressure in the reaction mixture.

79. The process of claim 64 wherein the reaction conditions of the contacting step includes the temperature being less than 230°

C.

80. The process of claim 64 further comprised of at least two reaction steps where a first reaction step has reaction temperatures greater than 200°

C. and the second reaction step has temperatures less than 220°

C. and

where the glycerol concentration entering the second reaction step is less than half the glycerol concentration entering the first reaction step.

81. The process of claim 80 wherein the first reaction step has reaction temperatures greater than 210°

C. and the second reaction step has temperatures less than 210°

C.

84. The process of claim 81 where the partial pressure of glycerol is less than glycerol'"'"'s dew point partial pressure in the reaction mixture and

greater than one fourth the dew point partial pressure in the reaction mixture.

85. The process of claim 84 where the partial pressure of glycerol is greater than half the dew point partial pressure in the reaction mixture.

82. A process for converting glycerol to a product at high selectivity to propylene glycol and low selectivity to ethylene glycol, comprising:

contacting a gas phase reaction mixture with a heterogeneous catalyst,

wherein the gas phase that contains essentially no liquid and has a partial pressure of glycerol between 0.01 and 0.5 bars of glycerol and a total pressure between 25 and 500 bars; and

establishing a temperature between 150°

C. and 280°

C. to facilitate a reaction.

83. The process of claim 82, wherein the heterogeneous catalyst used in the step of contacting contains at least one element from Groups I or VIII of the Periodic Table.

86. A process for converting glycerol to a product at high selectivity to a mixture of acetol and propylene glycol and low selectivity to ethylene glycol, comprising:

contacting a gas phase reaction mixture with a heterogeneous catalyst,

wherein the gas phase reaction mixture contains essentially no liquid and has a partial pressure of glycerol between 0.01 and 0.5 bars of glycerol and a partial pressure of hydrogen between 0.01 and 25 bars of hydrogen; and

establishing a temperature between 150°

C. and 250°

C. to facilitate a reaction.

87. The process of claim 86, wherein the heterogeneous catalyst used in the step of contacting contains at least one element from Groups I or VIII of the Periodic Table

88. The process of claim 86, wherein the total pressure of reaction between 0.02 and 25 bars

89. The process of claim 88 where the partial pressure of glycerol is

less than glycerol'"'"'s dew point partial pressure in the reaction mixture and

greater than one fourth the dew point partial pressure in the reaction mixture.

90. The process of claim 89 where the partial pressure of glycerol is greater than half the dew point partial pressure in the reaction mixture.

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

combining a glycerol-containing feedstock with a catalyst that is capable of dehydrating glycerol to form a reaction mixture; and

heating the reaction mixture to a temperature between 150°

to 200°

C. at a pressure between 0.02 and 25 bar.

92. The process of claim 91, wherein the catalyst used in the step of combining is contains an element of the subgroups from Group I, Group VI, and/or Group VIII.

93. The process of claim 91, wherein the glycerol-containing feedstock used in the step of combining contains from 0% to 15% water in glycerol by weight.

94. The process of claim 91, 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.

95. The process of claim 91, further comprising a glycerol-containing feedstock with less than 50% by weight water and a step of removing reaction product vapors that form during the step of heating.

96. The process of claim 95, comprising a step of condensing the vapors to yield liquid reaction product.

97. The process of claim 96, wherein the temperature used in the heating step exists within a range from 165°

C. to 185°

C.

98. The process of claim 97, wherein the pressure used in the heating step exists within a range from 0.02 to 2 bars,

99. The process of claim 96, wherein the step of condensing occurs using a condenser operating at a temperature between 0°

C. to 140°

C.

100. A process for purifying a propylene glycol product containing glycol esters converting comprising the steps of:

adding a base to the said propylene glycol product to achieve a pH greater than 8.0 and

distilling the propylene glycol from the product having a pH greater than 8.0.

101. The process of claim 100, wherein the base is selected from the group comprised of sodium hydroxide, potassium hydroxide, and calcium oxide.

102. A reactor for use with highly exothermic reactions comprised of an outer shell containing U-tubes with an orientation such that the U-end of the U-Tubes is facing upward,

said shell having an upper removable head

where catalyst is loaded between shell and tubes from the top by removing the upper head.

103. The reactor of claim 102, wherein an inert packing is placed in the lowest portion of the space between the shell and U-Tubes at a depth between 2 and 24 inches.

104. A process for converting glycerol to a product at high selectivity to acetol, comprising:

providing a gas phase reaction mixture that is essentially free of liquid and contains glycerol with a partial pressure of glycerol in a range from 0.01 bars and 0.5 bars of glycerol and

contacting the gas phase reaction mixture with a heterogeneous catalyst at a temperature between 150°

C. and 240°

C. to form acetol.

105. A process of claim 104 where the catalyst contains an element of Subgroup VI.

106. A process of claim 104 where the total pressure is between 0.02 and 25 bars.

107. The process of claim 104 wherein the gas phase reaction mixture contains a partial pressure of hydrogen between 0.002 and 0.2 bars.