Multifunctional mesoporous silica catalyst
The present invention provides bifunctional silica mesoporous materials, including mesoporous silica nanoparticles (“MSN”), having pores modified with diarylammonium triflate and perfluoroaryl moieties, that are useful for the acid-catalyzed esterification of organic acids with organic alcohols.
1. A method for preparing an ester, comprising combining an organic acid, an alcohol, and an acidic mesoporous silicate under conditions wherein the mesoporous silicate catalyzes the formation of the ester of the acid and the alcohol and wherein the silicate comprises diarylammonium triflate groups and perfluoroaryl groups in the pores of said silicate, wherein said groups are linked to the silicate matrix by inert organic groups.
2. A method for preparing a fatty acid (C 1 -C 3 ) alkyl ester from a fatty acid comprising combining a fatty acid, a (C 1 -C 3 ) alcohol, and an acidic mesoporous silicate under conditions wherein the mesoporous silicate catalyzes formation of the corresponding (C 1 -C 3 ) alkyl ester, and wherein the silicate comprises diarylammonium triflate groups and perfluoroaryl groups in the pores thereof, wherein said groups are linked to the silicate matrix by inert organic groups.
3. A method for preparing fatty acid (C 1 -C 3 ) alkyl esters from a feedstock comprising one or more fatty acid glycerol esters and one or more fatty acids comprising combining the feedstock, a (C 1 -C 3 ) alcohol, and an acidic mesoporous silicate under conditions wherein the mesoporous silicate catalyzes the formation of the corresponding fatty acid (C 1 -C 3 ) alkyl esters, and wherein the silicate comprises diarylammonium triflate groups and perfluoroaryl groups in the pores thereof, wherein said groups are linked to the silicate matrix by inert organic groups.
4. The method of claim 1 , 2 or 3 wherein the said diarylammonium triflate groups comprise 2,4,6-trimethylphenyl(phenyl) ammonium triflate moieties.
5. The method of claim 1 , 2 or 3 wherein the perfluoroaryl groups are pentafluorophenyl groups.
6. The method of claim 1 , 2 or 3 wherein the acidic mesoporous silicate is in the form of particles having a diameter of about 100-500 nm.
7. The method of claim 1 , 2 or 3 wherein the pores have a diameter of about 1-5 nm.
8. The method of claims 2 or 3 wherein the fatty acid comprises a C 7 -C 22 fatty acid.
9. The method of claim 3 wherein the ester is a tri-ester of glycerol.
10. The method of claim 9 , wherein the tri-ester comprises one or more C 8 -C 22 fatty acid esters.
11. The method of claim 2 wherein the fatty acid glycerol ester is a glyceride in an animal fat or oil.
12. The method of claim 11 wherein the fatty acid glycerol ester is a glyceride in a vegetable oil.
13. The method of claim 1 , 2 or 3 wherein the alcohol is methanol or ethanol.
14. The method of claim 13 wherein the alcohol is methanol.
15. The method of claim 1 , 2 or 3 wherein the formation of the ester is carried out at a temperature of less than about 150° C.
16. The method of claim 1 , 2 or 3 wherein the inert organic groups are (C 2 -C 10 )alkyl.
17. The method of claim 1 , 2 or 3 wherein aryl is (C 6 -C 10 )aryl.
18. The method of claim 1 , 2 or 3 wherein aryl is phenyl.