Anilide Herbicide Suspension Stability via Anionic Surfactant
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Solution Overview
Problem
Formulating stable, water-based suspension concentrates of sparingly soluble anilide herbicides is challenging due to Ostwald ripening, which leads to particle size growth, crystal formation, and instability, affecting shelf-life and application efficacy.
Innovation Solution
A stable agrochemical composition comprising a dispersed phase of pre-treated anilide herbicide and a continuous aqueous phase with at least one anionic surfactant, where the anilide herbicide is pre-treated through heat processes to stabilize the molecule, and the composition is formulated as a suspension concentrate with controlled particle size distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If anilide herbicide is formulated as aqueous suspension concentrate, then water-based dispersion is achieved, but Ostwald ripening causes particle size growth and crystal formation
Solution Approach 1:
The patent introduces a specific dispersant as an intermediary substance between the anilide herbicide particles and water. This dispersant adsorbs onto the particle surfaces, providing steric or electrostatic repulsion that prevents particle aggregation and Ostwald ripening, thereby maintaining stable particle size distribution in the aqueous suspension concentrate.
Solution Approach 2:
The patent modifies the surface properties of anilide herbicide particles through treatment with specific dispersants, changing parameters such as surface charge, hydrophilicity, and surface energy. These parameter changes prevent particle aggregation and crystal growth, enabling stable water-based formulations without Ostwald ripening.
2Ease of manufacture
If conventional surfactants are used to facilitate dispersion, then dispersion is improved, but solubility modification leads to aqueous phase instability
Solution Approach 1:
The patent employs specific dispersants that function effectively at low concentrations and provide stable dispersion without long-term solubility issues. These dispersants are selected to provide sufficient stabilization during the product shelf life without causing delayed solubility changes or phase separation.
Solution Approach 2:
The dispersant acts as an intermediary that facilitates particle-water interaction without significantly altering the solubility equilibrium of the anilide herbicide. This prevents the harmful effect of modified solubility while achieving good dispersion.
3Object-affected harmful factors
If particles are suspended in aqueous medium, then inhalation danger is reduced, but particle settling occurs during storage
Solution Approach 1:
The dispersant serves as an intermediary that provides repulsive forces between particles, counteracting gravitational settling. This creates a kinetically stable suspension where particles remain dispersed during storage, eliminating both inhalation risks and settling problems.
Solution Approach 2:
The patent creates a dynamic equilibrium in the suspension where repulsive forces from the dispersant continuously counteract gravitational attraction, preventing particle settling while maintaining safe water-based formulation for reduced inhalation exposure.
Data Source
AI summary
The present invention provides a stable agrochemical composition including a dispersed phase comprising an anilide herbicide; a continuous aqueous phase; and at least one anionic surfactant. The present invention also provides a process of preparing stable agrochemical compositions and methods of application thereof.