Herbicidal Oil Dispersion Stability via Segmented Solvent System
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Solution Overview
Problem
Combining fluroxypyr and sulfonylurea herbicides into a single stable formulation has been challenging due to their differing chemical, biological, and physicochemical properties, leading to instability and degradation issues, particularly with sulfonylureas like metsulfuron methyl, which affects storage stability and compatibility.
Innovation Solution
An oil dispersion comprising a non-aqueous solvent system with metsulfuron methyl as a sodium salt suspended and fluroxypyr-meptyl dissolved, using isobornyl acetate as a solvent that maintains stability, prevents settling, and allows for easy resuspension, while avoiding compatibility issues and enabling the inclusion of additional adjuvants.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If fluroxypyr and sulfonylurea herbicides are combined into a single formulation, then convenience for end users and weed control spectrum are improved, but storage stability and chemical compatibility deteriorate due to differing physicochemical properties
Solution Approach 1:
The formulation segments the herbicide components into distinct functional phases: fluroxypyr-meptyl dissolved in aromatic hydrocarbon solvent forms the continuous oil phase, while metsulfuron methyl is suspended as discrete particles. This segmentation allows each component to maintain its optimal chemical environment, preventing degradation while enabling combined application.
Solution Approach 2:
The aromatic hydrocarbon solvent acts as an intermediary medium that dissolves fluroxypyr-meptyl and suspends metsulfuron methyl particles, facilitating compatibility between the two herbicides. The solvent system mediates the interaction between components with differing solubility requirements, maintaining formulation stability during storage.
2Ease of operation
If metsulfuron methyl is formulated in liquid formulations, then ease of application is improved, but hydrolysis and degradation increase due to chemical instability
Solution Approach 1:
The formulation changes the physical state of metsulfuron methyl from dissolved to suspended particulate form, and uses a non-aqueous aromatic hydrocarbon solvent system. This parameter change reduces water availability for hydrolysis reactions while maintaining liquid formulation properties for easy application and mixing.
3Productivity
If aromatic hydrocarbon solvents are used to enhance fluroxypyr penetration, then herbicide efficacy is improved, but sulfonylurea degradation is accelerated due to chemical incompatibility
Solution Approach 1:
The formulation applies local quality by providing different micro-environments for each herbicide: fluroxypyr-meptyl is dissolved in the aromatic hydrocarbon continuous phase where it can penetrate leaf waxes effectively, while metsulfuron methyl is suspended as particles protected from direct contact with the solvent, reducing degradation while maintaining penetration efficacy.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The formulation exhibits excellent physical stability, ease of application, high biological effectiveness, and crop compatibility, with improved chemical stability and reduced sedimentation, effectively delivering the herbicides without decomposition.
Implementation Method 1
metsulfuron methyl as a sodium salt suspended in the solvent system
Implementation Method 2
fluroxypyr-meptyl, dissolved in the solvent system
Implementation Method 3
SUs are known to be unstable as they have a tendency to hydrolyse via cleavage at the sulfonylurea bridge
Data Source
AI summary
The present invention provides a herbicidal oil dispersion comprising: a non-aqueous solvent system; a sulfonylurea, as the alkali metal salt or alkaline earth metal salt thereof, suspended in the non-aqueous solvent system; and at least one of fluroxypyr, fluroxypyr-meptyl, or fluroxypyr- butoxypropyl dissolved in the non-aqueous solvent system. The invention also relates to the use of isobornyl acetate for suspending the alkali metal salt or alkaline earth metal salt of a sulfonylurea in a herbicidal oil dispersion.