METHOD FOR PROTECTING GLYCEROL ALKYL ETHERS FROM OXIDATION
Method of protecting glycerol alkyl ethers from oxidation, comprising steps (a.) and (b.): a. providing a glycerol alkyl ether of the general formula (Ia) or (Ib): R—O—CH 2 —CHOH—CH 2 OH (Ia) or H—O—CH 2 —CHOR—CH 2 OH (Ib) wherein, in general formula (Ia) or (Ib), R is C 3 -C 18 branched or unbranched alkyl or alkenyl group, optionally substituted by a hydroxyl, C 1 -C 4 alkoxy group, or both, and the C 3 -C 18 alkyl group is optionally interrupted by oxygen atoms, or R is a C 6 -C 10 aromatic hydrocarbon, optionally substituted by a hydroxyl, C 1 -C 4 alkoxy group, or both, and b. adding to the glycerol alkyl ether of step (a.) one or more compound selected from general formula (II): wherein each of R 1 -R 10 is hydrogen, hydroxyl, alkyl hydroxyl, alkoxy, alkyl ether, alkyl ester or glycoside, wherein the alkyl, alkoxy, and alkyl portion of the ester contains 1-4 carbon atoms, optionally branched, and the ester of the alkyl ester contains 1-5 carbon atoms, optionally branched.
1 . A method of protecting glycerol alkyl ethers from oxidation, comprising step (a.) and step (b.):
a. providing a glycerol alkyl ether of the general formula (Ia) or (Ib):
R—O—CH 2 —CHOH—CH 2 OH (Ia) or
H—O—CH 2 —CHOR—CH 2 OH (Ib)
wherein, in general formula (Ia) or (Ib), R is a C 3 -C 18 alkyl or alkenyl group, in which the alkyl or alkenyl group is branched or unbranched, unsubstituted or substituted by one or more hydroxyl, one or more C 1 -C 4 alkoxy groups, or both one or more hydroxyl and one or more C 1 -C 4 alkoxy groups, and the C 3 -C 18 alkyl group, whether branched or unbranched, unsubstituted or substituted, is optionally interrupted by up to four oxygen atoms, or R is a C 6 -C 10 aromatic hydrocarbon, unsubstituted or substituted by one or more hydroxyl, one or more C 1 -C 4 alkoxy groups, or both one or more hydroxyl and one or more C 1 -C 4 alkoxy groups, and
b. adding to the glycerol alkyl ether of the general formula (Ia) or (Ib) one or more compound selected from general formula (II):
wherein, in the general formula (II), each of R 1 -R 10 is independently selected from hydrogen, hydroxyl, alkyl hydroxyl, alkoxy, alkyl ether, alkyl ester and glycoside, wherein the alkyl, the alkoxy and the alkyl portion of the alkyl ester contains from 1 to 4 carbon atoms, branched or unbranched, and the ester of the alkyl ester contains from 1 to 5 carbon atoms, branched or unbranched.
2 . The method of claim 1 wherein, in the general formula (Ia) or (Ib), R is a branched or unbranched C 4 -C 12 alkyl group.
3 . The method of claim 1 wherein, in the general formula (Ia) or (Ib), R is 2-ethylhexyl.
4 . The method of claim 1 wherein, in the general formula (Ia) or (Ib), R is n-octyl.
5 . The method of claim 1 wherein, in the general formula (Ia) or (Ib), R is 2-octyl.
6 . The method of claim 1 wherein, in the general formula (Ia) or (Ib), R is heptyl.
7 . The method of claim 1 wherein, in the general formula (Ia) or (Ib), R is isoamyl.
8 . The method of claim 1 wherein, in the one or more compound selected from the general formula (II), each of R 1 -R 10 is independently selected from hydrogen, hydroxyl, alkyl hydroxyl and alkoxy.
9 . The method of claim 1 wherein, in the general formula (Ia) or (Ib), R is a branched or unbranched C 4 -C 12 alkyl group and in the one or more compound selected from the general formula (II), each of R 1 -R 10 is independently selected from hydrogen, hydroxyl, C 1 -C 4 alkyl hydroxyl and C 1 -C 4 alkoxy.
10 . The method of claim 1 wherein the one or more compound selected from the general formula (II) is one or a combination of two or more of hesperetin, naringenin, taxifolin, epicatechin, isokuranetin, eriodictyol, aromadendrin, aromadedrin, acacetin, isocutellarein, luteolin, kaempferol, quercetin, apigenin, diosmetin, chrysoeriol, chrysin, and galangin.
11 . The method of claim 1 wherein in the general formula (Ia) or (Ib), either R is 2-ethylhexyl or R is n-octyl or R is 2-octyl, and the one or more compound selected from the general formula (II), is one or a combination of two or more of hesperetin, naringenin, eriodyctiol, taxifolin, epicatechin, isokuranetin, aromadendrin, aromadedrin, acacetin, isocutellarein, luteolin, kaempferol, quercetin, apigenin, diosmetin, chrysoeriol, chrysin, and galangin.
12 . The method of claim 1 wherein, in the general formula (Ia) or (Ib), R is a branched or unbranched C 4 -C 12 alkyl group and in the one or more compound selected from the general formula (II), R 1 , R 3 , R 6 , R 7 and R 10 are H, R 2 and R 4 are OH, R 5 and R 9 are H or OH, and Fe is OH or C 1 -C 4 alkoxy.
13 . The method of claim 1 wherein the compound of general formula (II) comprises a flavanone, a flavonol, a flavone, a polymethoxylated flavanone, a polymethoxylated flavonol, a polymethoxylated flavone, a glycoside of a flavanone, a glycoside of a flavonol, a glycoside of a flavone, or a mixture of any two or more of the foregoing.
14 . The method of claim 1 wherein the compound of general formula (II) comprises one or a mixture of two or more of compounds having the general formulae (IIa), (IIb), or (IIc):
wherein, in the general formulae (IIa), (IIb), and (IIc), each of R 1 -R 10 are as defined above for the compound of general formula (II).
15 . The method of claim 1 wherein the composition contains from about 50 ppm to about 50000 ppm of the compound of general formula (II), based on the content of the compound of general formula (Ia) or (Ib).
16 . The method of claim 1 wherein the compound of general formula (Ia) or (Ib) is provided at a purity of at least 95%, prior to addition of the compound of general formula (II).