Stabilized herbicidal composition
View Patent ↗A herbicide composition includes a fenoxaprop ester and a weak acid buffer system. The buffer system maintains the herbicidal composition at a pH in the range of 4 to 8. In one non-limiting embodiment, the fenoxaprop ester is fenoxaprop ethyl. The buffer system can include an amine-containing material, such as a tertiary amine. The herbicide composition can include other herbicides, such as weak acid herbicides, for example pyrasulfotole, bromoxynil, and/or bromoxynil esters and can include one or more safeners.
1. A method of improving the stability of an herbicidal composition comprising:
a) combining fenoxaprop ethyl with a buffer system consisting essentially of
i) triethanolamine; and
ii) one or more weak acid herbicides comprising pyrasulfotole to form a stable herbicidal composition,
wherein said fenoxaprop ethyl combined with said buffer system has improved stability relative to an herbicidal composition that contains fenoxaprop ethyl and a weak acid herbicide in combination without said triethanolamine, and
wherein the improved stability of the fenoxaprop ethyl is quantifiable as a decreased amount of fenoxaprop ethyl degradation, as compared to the amount of degradation observed in fenoxaprop ethyl when combined with a weak acid in the absence of triethanolamine.
2. The method of claim 1 wherein said herbicidal composition comprises 3 to 6 wt % pyrasulfotole and 7 to 10 wt % fenoxaprop ethyl.
3. The method of claim 1 wherein said buffer system comprises 1 to 4 wt % triethanolamine.
4. The method of claim 1 , further comprising adding a safener to said composition.
5. The method of claim 4 wherein said safener is selected from the group consisting of mefenpyr, isoxadifen, fenchlorazole and cloquinocet.
6. The method of claim 4 wherein said safener comprises 3 to 6 wt % mefenpyr.
7. The method of claim 1 , wherein the herbicidal composition is an emulsion concentrate formulation.
8. The method of claim 2 , wherein the herbicidal composition is an emulsion concentrate formulation.
9. The method of claim 1 , wherein said herbicidal composition further comprises benzene sulfonic acid calcium salt.
10. The method of claim 1 wherein said herbicidal composition comprises 3 to 6 wt % pyrasulfotole and 7 to 10 wt % fenoxaprop ethyl and 1 to 4 wt % triethanolamine.
11. The method of claim 1 wherein said herbicidal composition comprises:
3 to 6 wt % pyrasulfotole,
7 to 10 wt % fenoxaprop ethyl;
1 to 4 wt % triethanolamine; and
3 to 6 wt % mefenpyr.
12. The method of claim 1 , wherein said buffer system maintains the herbicidal composition at a pH in the range of 4 to 8.
13. The method of claim 1 , wherein said buffer system maintains the herbicidal composition at a pH in the range of 5 to 7.5.
14. The method of claim 1 , wherein said buffer system maintains the herbicidal composition at a pH in the range of 5.8 to 7.5.
15. The method of claim 1 , wherein the stability of fenoxaprop ethyl in said herbicidal composition is improved after 8 weeks of incubation at 0° C. relative to fenoxaprop ethyl in an herbicidal composition without said buffer system.
16. The method of claim 1 , wherein the stability of fenoxaprop ethyl in said herbicidal composition is improved after 8 weeks of incubation at 40° C. relative to fenoxaprop ethyl in an herbicidal composition without said buffer system.
17. The method of claim 1 , wherein the stability of fenoxaprop ethyl in said herbicidal composition is improved after 8 weeks of incubation at 50° C. relative to fenoxaprop ethyl in an herbicidal composition without said buffer system.
18. The method of claim 1 , wherein the buffer system consists of
i) triethanolamine; and
ii) one or more weak acid herbicides comprising pyrasulfotole to form a stable herbicidal composition.
19. A method of improving the stability of an herbicidal composition consisting essentially of:
a) combining fenoxaprop ethyl with a buffer system consisting essentially of
i) triethanolamine; and
ii) one or more weak acid herbicides comprising pyrasulfotole to form a stable herbicidal composition,
wherein said fenoxaprop ethyl combined with said buffer system has improved stability relative to an herbicidal composition that contains fenoxaprop ethyl and a weak acid herbicide in combination without said triethanolamine, and
wherein the improved stability of the fenoxaprop ethyl is quantifiable as a decreased amount of fenoxaprop ethyl degradation, as compared to the amount of degradation observed in fenoxaprop ethyl when combined with a weak acid in the absence of triethanolamine.
20. The method of claim 19 , wherein the buffer system consists of
i) triethanolamine and
ii) one or more weak acid herbicides comprising pyrasulfotole to form a stable herbicidal composition.