Process for the production of esters from vegetable oils or animal oils alcohols

• US 5,908,946 A
• Filed: 08/08/1997
• Issued: 06/01/1999
• Est. Priority Date: 08/08/1996
• Status: Expired due to Term

• Current Assignee: Institut Francais Du Petrole
• Original Assignee: Institut Francais Du Petrole
• Inventors: Leporq, Serge, Rouxel, Jean-Jacques, Hillion, Gerard, Stern, Robert
• Primary Examiner(s): Killos, Paul J.
• Assistant Examiner(s): PARSA, JAFAR F
• Application Number:
  US08/908,983
• Time in Patent Office: 662 Days
• Field of Search: 554/167, 554/168
• US Class Current: 554/167
• CPC Class Codes: C07C 67/03 by reacting an ester group with a hydroxy group
• CPC Class Codes: C07C 69/52 Esters of acyclic unsaturated carboxylic acids having the esterified carboxyl group bound to an acyclic carbon atom
• CPC Class Codes: C10L 1/02 essentially based on components consisting of carbon, hydrogen, and oxygen only
• CPC Class Codes: C11C 3/003 by esterification of fatty acids with alcohols C11C3/02 takes precedence

Abstract

For the production of linear monocarboxylic acid esters with 6 to 26 carbon atoms vegetable oils or animal oils, which may or may not be neutral, are reacted with monoalcohols having a low molecular weight, for example 1 to 5 carbon atoms, in the presence of a catalyst that is selected from among zinc oxide, mixtures of zinc oxide and aluminum oxide, and the zinc aluminates that correspond to the formula:

ZnAl.sub.2 O.sub.4, x ZnO, y Al.sub.2 O.sub.3

(with x and y each being in the range of 0-2) and having more particularly a spinel type structure, thereby enabling the direct production in one or more stages, of an ester that can be used as a fuel or combustible and a pure glycerine.

Claims

1. Process for the production of at least one fatty acid ester and glycerine, characterized in that it comprises

the reaction of a vegetable or animal oil with an aliphatic monoalcohol that contains 1 to 18 carbon atoms, in the presence of at least one catalyst comprising a mixture of zinc oxide, aluminum oxide, and zinc aluminates that corresponds to the formula:

ZnAl₂ O₄, x ZnO, y Al₂ O₃, where each of x and y are each between 0 and 2, and wherein at least 10% of total ZnO is in the form of ZnAl₂ O₄ ;

the elimination of substantially all excess monoalcohol; and

the separation of the fatty acid ester from glycerine.

2. A process according to claim 1, wherein said aliphatic monoalcohol contains 1 to 5 carbon atoms.

3. A process according to claim 1, wherein said catalyst comprises a zinc spinel or zinc aluminate, and the operation is carried out at a temperature of between 170°

C. and 250°

C., at a pressure of less than 100 bar, and with excess monoalcohol relative to oil/alcohol stoichiometry.

4. A process according to claim 1, wherein said catalyst comprises an zinc oxide in the form of powder, extrudates, or balls and the operation is carried out at a temperature of between 170 and 250°

C., at a pressure of less than 100 bar, and with excess monoalcohol relative to oil/alcohol stoichiometry.

5. A process according to claim 1, wherein the catalyst has a surface area of 10 to 200 m² /g, a pore volume of 0.2 to 1.2 cm³ /g, and a pore distribution of between 0.01 and 0.1 micron.

6. A process according to claim 5, wherein the catalyst has a surface area of 50 to 200 m2/g and a pore volume that is greater than 0.3 cm3/g.

7. A process according to claim 1, wherein the reaction is employed discontinuously.

8. A process according to claim 1, wherein the reaction is employed continuously, either in a fixed bed or with serial autoclaves and decanters.

9. A process according to claim 8, wherein the reaction is employed in a fixed bed, with VVH of 0.3 to 3.

10. A process according to claim 1, comprising the following successive steps:

(a) conducting an initial transesterification with at least 80-85% conversion of the oil into fatty acid ester;

(b) evaporating and recovering excess monoalcohol;

(c) decanting resultant glycerine and ester mixture, wherein said ester mixture comprises fatty acid esters and unreacted or partially reacted oil;

(d) said ester mixture being separated from said glycerine and recycled into a second stage transesterification between a portion of the monoalcohol that is recovered in step (b) and unreacted or partially reacted oil in said ester mixture; and

(e) re-evaporating the excess monoalcohol from the second transesterification step, and decanting and separating the resultant glycerine and the fatty acid ester.

11. A process according to claim 1, wherein the starting oil is an acidic oil, and a preliminary glycerolysis operation is conducted to obtain with a catalyst used for the transesterification, free fatty acid at a temperature of between 180 and 220°

C. and at a pressure of equal to or less than 1 bar.

12. A process according to claim 1, wherein the ester that is obtained is purified by being passed over a resin, an adsorbent earth, and/or active carbon.

13. A process according to claim 1, wherein the resultant ester is purified either by distillation or by washing with methanol glycerine to reduce the monoglyceride content.

14. A process according to claim 1, wherein to produce the ethyl ester, ethyl alcohol is mixed with a proportion of 1 to 50% of methanol is used.

15. A process according to claim 1, wherein the glycerine that is obtained after evaporation of the alcohol undergoes final purification by being passed over a resin, an adsorbent earth, and/or active carbon.

16. A fuel ester obtained by a process according to claim 1, containing a sterol ester content of less than 0.2% and a monoglyceride content of 0.5-5% and being essentially free of diglycerides and trigylcerides.

17. A glycerine obtained by a process according to claim 1, having a purity of greater than 99.5%.

18. A process according to claim 9, wherein the reaction is conducted at a VVH of 0.5 to 2.

19. A process according to claim 1, wherein the glycerine obtained has a purity of greater than 99.5%.

20. A process according to claim 1, wherein at least 20% of total ZnO is in the form of ZnAl₂ O₄.

21. A process according to claim 1, wherein at least 30% of total ZnO is in the form of ZnAl₂ O₄.