Ester formation of fatty acid and hydroxycarboxylic acid
A process for the transesterification of a fatty acid ester of a lower alcohol and a salt of hydroxycarboxylic acid without making use of organic solvents is provided. The process can also be carried out without added anionic surface active agents.
1. A process for the preparation of a salt of a fatty acid ester of hydroxycarboxylic acid which comprises heating a salt of hydroxycarboxylic acid with a catalyst in admixture with a C8-C24 fatty acid ester of a lower alcohol having 1-4 carbon atoms at a temperature at which there exists a liquid phase and subjecting the mixture to ester interchange whereby the temperature of the process is kept at or below the boiling point of the C8-C24 fatty acid ester of a lower alcohol having 1-4 carbon atoms,
wherein the heating and ester interchange are carried out under conditions such that byproduced water and lower alcohol are removed during the process.
2. The process according to claim 1 , wherein the temperature of the process is kept between the melting temperature of the salt of hydroxycarboxylic acid and the boiling point of the C8-C24 fatty acid ester of a lower alcohol having 1-4 carbon atoms.
3. The process according to claim 1 , wherein the temperature of the process is from 160 to 200° C.
4. The process of according to claim 1 , wherein said hydroxycarboxylic acid is lactic acid.
5. The process according to claim 4 , wherein said salt of hydroxycarboxylic acid is sodium lactate.
6. The process according to claim 1 , wherein said C8-C24 fatty acid ester of a lower alcohol having 1-4 carbon atoms is a C8-C18 fatty acid ester of a lower alcohol having 1-4 carbon atoms.
7. The process according to claim 1 , wherein the lower alcohol of said C8-C24 fatty acid ester has 1-2 carbon atoms.
8. The process according to claim 7 , wherein the C8-C24 fatty acid ester of a lower alcohol having 1-4 carbon atoms is methyl laurate.
9. The process according to claim 8 , wherein said salt of hydroxycarboxylic acid is sodium lactate.
10. The process according to claim 1 , wherein said catalyst is (alkali metal)-OR wherein R is H or Me.
11. The process according to claim 1 , wherein the catalyst is NaOH or NaOMe.
12. The process according to claim 1 , wherein the molar ratio of said salt of hydroxycarboxylic acid to the C8-C24 fatty acid ester of a lower alcohol having 1-4 carbon atoms is from 0.2 to 20 moles per mole.
13. The process according to claim 1 performed in the presence of less than 15 mol. %, based on the number of moles of the salt of hydroxycarboxylic acid, of added surfactant selected from non-ionic surfactant, anionic surfactant and mixtures thereof.
14. The process according to claim 1 performed in the presence of less than 5 mol. % of added surfactant.
15. A process for the preparation of a salt of a fatty acid ester of hydroxycarboxylic acid which consists essentially of heating a salt of hydroxycarboxylic acid with a catalyst in admixture with a C8-C24 fatty acid ester of a lower alcohol having 1-4 carbon atoms at a temperature at which there exists a liquid phase and subjecting the mixture to ester interchange whereby the temperature of the process is kept at or below the boiling point of the C8-C24 fatty acid ester of a lower alcohol having 1-4 carbon atoms, wherein the heating and ester interchange are carried out under conditions such that byproduced water and lower alcohol are removed during the process.