Hydrolysis of methyl esters for production of fatty acids
| Title: | Hydrolysis of methyl esters for production of fatty acids |
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| Patent Number: | 5,508,455 |
| Publication Date: | April 16, 1996 |
| Appl. No: | 08/324,272 |
| Application Filed: | October 14, 1994 |
| Abstract: | The present invention relates to an improved process for preparing fatty acids from alkyl, preferably methyl esters via acid hydrolysis by using ratios of water/ester/acid catalyst to form single phase reaction mixtures wherein the initial stoichiometric ratio of water to ester is at least about 1:1. These ratios are represented by the ternary phase diagram of FIG. 1 for a preferred C.sub.6 -C.sub.14 alkylbenzene sulfonic acid catalyst having mid-point attachment of the alkyl chain to the benzene ring. |
| Inventors: | Gibson, Michael S. (Loveland, OH) |
| Assignees: | The Procter & Gamble Company (Cincinnati, OH) |
| Claim: | What is claimed is |
| Claim: | 1. A process for the production of fatty acids comprising the following steps |
| Claim: | (a) mixing specific ratios of fatty acid ester or mixtures thereof, with water and acid catalyst to form a single phase reaction mixture; and |
| Claim: | (b) heating the single phase reaction mixture to a temperature of from about 70.degree. C. to about 110.degree. C.; |
| Claim: | wherein the acid catalyst is substituted or non-substituted linear alkyl benzene sulfonic acid; wherein the initial stoichiometric ratio of water to ester is at least about 1:1; wherein the initial stoichiometric ratio of any residual amount of carboxylic acid, as a fatty acid ester impurity, to ester is less than 1:1 when said carboxylic acid contains less than 6 carbon atoms; wherein the ratios of acid catalyst/water/ester are the points in the area enclosed by the straight lines connecting points A (6.5/8.5/85) (catalyst/water/ester), B (90/0/10), C (96/2/2), D (1/97/2), E (21/49.5/29.5), F (11/27/62), G (8/24/68), and A (6.5/8.5/85), of FIG. 1, in order, excluding the shaded area, wherein the reaction mixture is essentially free of C.sub.2 -C.sub.5 carboxylic acid, and wherein the fatty acid ester has the formula: ##STR6## wherein R is a saturated or unsaturated aliphatic chain having from 5 to 20 carbon atoms, and R.sup.2 is a saturated or unsaturated aliphatic chain having from 1 to 4 carbon atoms. |
| Claim: | 2. The process of claim 1 wherein the ratios of acid catalyst/water/ester are the points in the area enclosed by the straight lines connecting points A (6.5/8.5/85) (catalyst/water/ester), K (50/4/46), L (50/22/28), M (36/29/35), N (36/33/31), O (18/42/40), F (11/27/62), G (8/24/68), and A (6.5/8.5/85) FIG. 1, in order. |
| Claim: | 3. The process of claim 2 wherein the ratios of catalyst/water/ester are the points in the area enclosed by the straight lines connecting points A (6.5/8.5/85), H (32/6/62), I (32/24/44), J (14/33/53), F (11/27/62), G (8/24/68), and A (6.5/8.5/85) FIG. 1, in order. |
| Claim: | 4. The process of claim 3 wherein the temperature of (b) is from about 95.degree. C. to about 110.degree. C. |
| Claim: | 5. The process of claim 1 wherein R is from about 6 to about 14 carbon atoms, and R.sup.2 is from about 1 to 2 carbon atoms. |
| Claim: | 6. The process of claim 5 wherein R is from 6 to about 12 carbon atoms, and R.sup.2 is a methyl group. |
| Claim: | 7. The process of claim 1 wherein the acid catalyst is recovered from the reaction mixture by the following steps |
| Claim: | (a) distilling the unreacted water, methanol and unreacted ester under vacuum; and |
| Claim: | (b) distilling the fatty acid product away from the product of (a) under vacuum. |
| Claim: | 8. The process of claim 7 wherein the temperature does not exceed about 163.degree. C. (325.degree. F.) for reaction mixtures containing C.sub.8 -C.sub.12 fatty acids. |
| Claim: | 9. The process of claim 8 wherein the temperature does not exceed about 150.degree. C. (302.degree. F.). |
| Claim: | 10. A process for the production of fatty acids comprising the following steps |
| Claim: | wherein the reaction mixture is essentially free of C.sub.2 -C.sub.5 carboxylic acid, wherein the initial stoichiometric ratio of water to ester is at least about 1:1; wherein the initial stoichiometric ratio of any residual amount of carboxylic acid, as a fatty acid ester impurity, to ester is less than 1:1 when said carboxylic acid contains less than 6 carbon atoms; wherein the ratios of acid catalyst/water/ester are the points in the area enclosed by the straight lines connecting points A (6.5/8.5/85) (catalyst/water/ester), B (90/0/10), C (96/2/2), D (1/97/2), E (21/49.5/29.5), F (11/27/62), G (8/24/68), and A (6.5/8.5/85), of FIG. 1, in order, excluding the shaded area; the acid catalyst is a substituted or non-substituted linear alkyl benzene sulfonic acid of the formula: ##STR7## wherein R.sup.3 is an alkyl group having from 1 to 20 carbon atoms, and mixtures thereof, and wherein the fatty acid ester has the formula: ##STR8## wherein R is a saturated or unsaturated aliphatic chain having from 5 to 20 carbon atoms, and R.sub.2 is a saturated or unsaturated aliphatic chain having from 1 to 4 carbon atoms. |
| Claim: | 11. The process of claim 10 wherein R.sup.3 is an alkyl group with from about 6 to 14 carbon atoms, and mixtures thereof. |
| Claim: | 12. The process of claim 11 wherein R.sup.3 is an alkyl group having from about 11 to 13 carbon atoms, and mixtures thereof. |
| Claim: | 13. The process of claim 10 wherein the R.sup.3 group is attached to the benzene ring. at the middle one-half of the alkyl chain. |
| Current U.S. Class: | 554/160 |
| Current International Class: | C11C 104 |
| Patent References Cited: | 601603 March 1898 Twitchell 1068079 July 1913 Reuter 1082662 December 1913 Twitchell 1298563 March 1919 Reuter 1576005 March 1926 Schrauth 1622974 March 1927 Richardson et al. 2042411 May 1936 Peirce 3907884 September 1975 Lynn et al. 4185027 January 1980 Logan et al. 4218386 August 1980 Logan et al. 4747969 May 1988 Rupilius et al. 5053535 October 1991 Shima et al. 5128070 July 1992 Sedelies et al. |
| Primary Examiner: | Dees, Jose G. |
| Assistant Examiner: | Barts, Samuel |
| Attorney, Agent or Firm: | Krivulka, Thomas G. Aylor, Robert B. Yetter, Jerry J. |
| Accession Number: | edspgr.05508455 |
| Database: | USPTO Patent Grants |
| Language: | English |
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