Agrochemical composition
The present invention provides a co-crystal of sulfentrazone and a triazinone herbicide and process for preparation thereof. The present invention also provides an agrochemical composition comprising said co-crystal and process of preparation of an agrochemical composition and method of controlling weeds with said compositions.
1 . A co-crystal comprising sulfentrazone and metribuzin, wherein the co-crystal is characterized by a powder X-ray diffraction pattern comprising at least one peak at a diffraction angle of 2θ value of 7.8°, 11.8°, 14.1°, 17.8°, 22.1°, 23.4° and 24.4° (±0.2), and wherein the sulfentrazone and metribuzin are present in said co-crystal in a molar ratio of from 1:9 to 9:1.
2 . The co-crystal as claimed in claim 1 , wherein said sulfentrazone and metribuzin are present in a molar ratio from 2:1 to 1:2.
3 . The co-crystal as claimed in claim 1 , wherein said co-crystal is characterized by at least one of following: a DSC thermogram comprising an endothermic peak with an onset at 107.3° C. and a peak at 110.5° C.; or a single crystal X-ray diffraction having lattice parameters:
a=22.2825(4) A, b=10.5240(2) A, c=11.4659(2) A, a=90°, b=93.5058°(7) and g=90°.
4 . A process for preparing the co-crystal of claim 1 , comprising solution crystallization or grinding or heating or solvent drop grinding or melt crystallization or mixing sulfentrazone and metribuzin in an aqueous condition.
5 . The process as claimed in claim 4 , comprising preparing a solution of sulfentrazone and metribuzin using an organic solvent, water, or a mixture of water and an organic solvent, and triturating or precipitating with an anti-solvent to obtain said co-crystal of sulfentrazone and metribuzin.
6 . The process as claimed in claim 5 , wherein said solvent is selected from the group consisting of aliphatic alcohols, ketones, esters, ethers, polar protic solvents, polar aprotic solvents, halogenated solvents, aliphatic hydrocarbon, and aromatic hydrocarbons; and said anti-solvent is selected from the group consisting of aliphatic and aromatic hydrocarbon solvents.
7 . The process as claimed in claim 4 , wherein said process comprises heating a mixture of sulfentrazone and metribuzin to melt and obtain said co crystal of sulfentrazone and metribuzin.
8 . An agrochemical composition comprising the co-crystal of claim 1 .
9 . The composition as claimed in claim 8 , wherein said co-crystal comprises 10-90% of sulfentrazone and 90-10% of metribuzin by weight of the composition.
10 . The composition as claimed in claim 8 , wherein said composition is a liquid composition.
11 . An agrochemical formulation comprising the composition of claim 8 , in the form of a suspension concentrate.
12 . A process for preparing an agrochemical composition comprising the co-crystal of claim 1 , said process comprising: a) pre-treatment to sulfentrazone and metribuzin to form the co crystal; and b) admixing the co-crystal of step (a) with agrochemically acceptable excipients to obtain said composition.
13 . The process as claimed in claim 12 wherein said agrochemical process comprises: a) pre-treatment to sulfentrazone and metribuzin by heating followed by cooling the mixture to room temperature to obtain the co-crystal; and b) admixing the co-crystal of step (a) with agrochemical excipients in presence of water to obtain a homogeneous agrochemical composition.
14 . The process for preparing the agrochemical composition as claimed in claim 11 , comprising a) preparing an aqueous mixture of agrochemically suitable excipients to obtain a homogeneous solution, b) adding metribuzin and sulfentrazone in the homogeneous solution of step (a) to obtain a slurry; c) optionally milling the slurry, d) heating the slurry of step (b) or (c) and cooling to room temperature, e) optionally charging other agrochemical excipient to the slurry of step (d), and mixing to provide a homogeneous agrochemical composition.
15 . A method of controlling weeds comprising applying to a plant, or its habitat, plant seed or soil, a herbicidally effective amount of the co-crystal of claim 1 .