Process for the decarboxylative ketonization of fatty acids or fatty acid derivatives

1. A process for the decarboxylative ketonization of fatty acids, fatty acid derivatives or mixtures thereof in the liquid phase with metal compounds as catalyst, wherein

a) in a first step, elementary metal or a metal compound and the fatty acid, fatty acid derivative or mixture thereof comprising at least 10 mol %, based on the entire amount of fatty acids or fatty acid derivatives, of fatty acids having 12 carbon atoms or less or derivatives of fatty acids having 12 carbon atoms or less, are mixed in a molar ratio of from 1:0.8 to 1:3.5 (molar ratio metal: carboxyl group equivalent) and reacted for a period P 1 of from 5 min to 24 h at a temperature T 1 of from 100° C. to 270° C. in the substantial absence of added solvents, and

b) thereafter the temperature is raised to a temperature T 2 which is strictly above 270° C. and up to 400° C., and additional fatty acids, fatty acid derivatives or a mixture thereof comprising at least 10 mol %, based on the entire amount of fatty acids or fatty acid derivatives, of fatty acids having 12 carbon atoms or less or derivatives of such fatty acids, is added over a period of time P 2 of from 5 min to 24 h in the substantial absence of added solvents until the molar ratio of fatty acid, fatty acid derivatives or mixtures thereof to metal is in the range of from 6:1 to 99:1.

2. The process according to claim 1 wherein temperature T 1 is from 230° C. to 270° C.

3. The process according to claim 1 wherein temperature T 2 is from 280° C. to 320° C.

4. The process according to claim 3 wherein

temperature T 1 is from 180° C. to 270° C.,

period of time P i is from 5 min to 240 min, and

period of time P 2 is from 1 h to 24 h.

5. The process according to claim 1 wherein temperature T 2 is strictly above 320° C. and up to 360° C.

6. The process in accordance with claim 1 wherein a metal selected from the group consisting of Mg, Ca, Al, Ga, In, Ge, Sn, Pb, As, Sb, Bi, Cd and transition metals having an atomic number of from 21 to 30 or a mixture thereof or an oxide of these metals or a mixture thereof is used.

7. The process in accordance with claim 1 wherein water formed during the reaction is continuously removed from the reaction mixture.

8. The process in accordance with claim 4 wherein step a) is carried out at a temperature T 1 of from 190° C. to 260° C. for a duration of from 15 min to 120 min and the fatty acid, fatty acid derivative or mixture thereof in step b) is added over a period P 2 of from 2 hours to 12 hours.

9. The process in accordance with claim 1 wherein a fatty acid derivative selected from esters and anhydrides is used as starting material.

10. The process in accordance with claim 1 wherein one and only one fatty acid is used as starting material.

11. The process in accordance with claim 1 wherein a fatty acid cut is used as starting material.

12. The process in accordance with claim 11 wherein the acid cut is a coconut oil fatty acid cut.

13. The process in accordance with claim 1 wherein, after the temperature has been raised to T 2 and before the additional fatty acids, fatty acid derivatives or mixture thereof is added over period of time P 2 , said temperature is maintained at temperature T 2 during a period of time P 12 of from 30 min to 300 min.

14. The process in accordance with claim 1 wherein, after the additional fatty acids, fatty acid derivatives or mixture thereof has been added over period of time P 2 , the temperature is maintained at temperature T 2 during a period of time P 23 of from 30 min to 300 min.

15. The process in accordance with claim 1 wherein at the end of step b) the metallic compounds are separated from the products using conventional techniques and then are recycled for the conversion of another batch of fatty acids or fatty acids derivatives or a mixture thereof comprising at least 10 mol %, based on the entire amount of fatty acids or fatty acid derivatives, of fatty acids having 12 carbon atoms or less or derivatives of such fatty acids.

16. The process according to claim 4 , wherein the temperature T 1 is from 210° C. to 260° C.

17. The process in accordance with claim 10 wherein the one and only one fatty acid is capric acid or lauric acid.

18. The process according to claim 1 , wherein an internal ketone manufactured through decarboxylative ketonization of the fatty acid, fatty acid derivative or mixture thereof is subjected to a hydrogenation reaction to manufacture a secondary fatty alcohol.

19. The process according to claim 18 , wherein the secondary fatty alcohol is further converted to an internal olefin by a dehydration reaction.

20. The method according to claim 19 , wherein the internal olefin obtained after the dehydration is sulfonated, followed by an alkaline hydrolysis to obtain an internal olefin sulfonate.