Fatty ester compositions with improved oxidative stability
View Patent ↗Compositions containing unsaturated fatty esters may be stabilized against atmospheric oxidation by the addition of an antioxidant package containing a phenolic oxidant and a nonphenolic oxygen scavenger, which may be a hydroxylamine, an amine N-oxide, an oxime, or a nitrone. If an amine N-oxide is used, it may be used with or without a phenolic antioxidant. Compositions treated in this manner show good resistance to atmospheric oxidation and resultant viscosity increase.
1. A composition comprising:
a) a fatty ester component constituting at least 50 wt % of the composition and comprising an unsaturated fatty ester; and
b) an antioxidant package comprising a phenolic antioxidant or precursor thereof and a nonphenolic oxygen scavenger or precursor thereof;
wherein the nonphenolic oxygen scavenger or precursor thereof comprises a hydroxylamine, an amine N-oxide, an oxime, a nitrone, or a mixture of any of these.
2. The composition of claim 1 , wherein the nonphenolic oxygen scavenger or precursor thereof comprises a hydroxylamine.
3. The composition of claim 1 , wherein the nonphenolic oxygen scavenger or precursor thereof comprises an amine N-oxide.
4. The composition of claim 1 , wherein the nonphenolic oxygen scavenger or precursor thereof comprises a compound having a vapor pressure greater than 10 Torr at 25° C.
5. The composition of claim 1 , wherein the nonphenolic oxygen scavenger or precursor thereof constitutes from 0.001 to 5 wt % of the composition.
6. The composition of claim 1 , wherein the phenolic antioxidant or precursor thereof comprises hydroquinone.
7. The composition of claim 1 , wherein the phenolic antioxidant or precursor thereof comprises a catechol.
8. The composition of claim 1 , wherein the fatty ester component comprises a biodiesel.
9. The composition of claim 8 , further comprising a petroleum distillate.
10. The composition of claim 1 , wherein the nonphenolic oxygen scavenger or precursor thereof comprises diethylhydroxylamine and triethylamine N-oxide, the phenolic antioxidant comprises hydroquinone, and the fatty ester component comprises biodiesel.
11. A composition comprising:
a) a fatty ester component constituting at least 50 wt % of the composition and comprising an unsaturated fatty ester; and
b) an amine N-oxide.
12. A method of making a stabilized composition, comprising blending together:
a) a fatty ester component comprising an unsaturated fatty ester; and
b) an antioxidant package comprising a phenolic antioxidant or precursor thereof and a nonphenolic oxygen scavenger or precursor thereof;
wherein the nonphenolic oxygen scavenger or precursor thereof comprises a hydroxylamine, an amine N-oxide, an oxime, a nitrone, or a mixture of any of these.
13. The method of claim 12 , wherein the nonphenolic oxygen scavenger or precursor thereof comprises a hydroxylamine.
14. The method of claim 12 , wherein the nonphenolic oxygen scavenger or precursor thereof comprises an amine N-oxide.
15. The method of claim 12 , wherein the nonphenolic oxygen scavenger or precursor thereof comprises a compound having a vapor pressure greater than 10 Torr at 25° C.
16. The method of claim 12 , wherein the nonphenolic oxygen scavenger or precursor thereof constitutes from 0.01 to 5 wt % of the composition.
17. The method of claim 12 , wherein the phenolic antioxidant or precursor thereof comprises hydroquinone.
18. The method of claim 12 , wherein the phenolic antioxidant or precursor thereof comprises a catechol.
19. The method of claim 12 , wherein the fatty ester component comprises a biodiesel.
20. The method of claim 19 , wherein the composition further comprises a petroleum distillate.
21. The method of claim 12 , wherein the nonphenolic oxygen scavenger or precursor thereof comprises diethylhydroxylamine and triethylamine N-oxide, the phenolic antioxidant comprises hydroquinone, and the fatty ester component comprises biodiesel.
22. The method of claim 12 , wherein the phenolic antioxidant or precursor thereof comprises p-benzoquinone.