Copper-Phosphorous Acid Composition Stability at Neutral pH
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Solution Overview
Problem
Aqueous compositions containing copper ions and phosphorous acid are unstable at low pH, leading to precipitate formation and stability issues, which affects their commercial viability for controlling plant diseases.
Innovation Solution
Formulations with a pH of 6 to 10, comprising copper ions, phosphorous acid, and specific amines such as alkylamines and alkanolamines, stabilize the compositions, ensuring no detectable precipitate formation for at least one month.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the pH of the composition is lowered to increase copper ion solubility and disease control efficacy, then the antimicrobial effectiveness is improved, but the composition stability deteriorates due to precipitate formation
Solution Approach 1:
The patent applies parameter changes by adjusting the pH to a higher range (6-10) instead of using low pH, and by modifying the copper source from simple salts to basic copper carbonate or sulfate. This parameter change resolves the contradiction by maintaining copper ion availability for disease control while preventing precipitate formation through the buffer capacity of the higher pH range and the controlled solubility of basic copper compounds.
Solution Approach 2:
The patent uses composite materials by combining basic copper carbonate or sulfate with phosphorous acid and potassium carbonate in specific ratios. This composite approach creates a synergistic system where the basic copper compound provides sustained copper ion release, phosphorous acid enhances disease control, and potassium carbonate maintains pH stability, thereby achieving both efficacy and stability simultaneously.
2Reliability
If high concentrations of copper are used to enhance disease control, then the antimicrobial activity is improved, but the copper solubility decreases leading to precipitation
Solution Approach 1:
The patent changes the chemical form of copper from simple soluble salts to basic copper carbonate or sulfate, which have controlled solubility characteristics. This parameter change allows high concentrations of copper to be present in the composition while maintaining solubility through the basic salt structure, preventing precipitation while preserving antimicrobial activity.
Solution Approach 2:
The patent applies local quality by creating a localized high-copper environment at the application site through controlled dissolution of basic copper carbonate or sulfate. The copper ions are released gradually where needed for disease control, while the bulk composition remains stable with lower free copper ion concentration, thus achieving high antimicrobial activity without overall solubility problems.
3Reliability
If phosphorous acid and copper ions are combined at high concentrations for enhanced disease control, then the efficacy is improved, but the composition becomes unstable with precipitate formation
Solution Approach 1:
The patent applies parameter changes by adjusting the pH to a higher range (6-10) and using basic copper carbonate or sulfate instead of simple copper salts. This parameter change resolves the incompatibility between high concentrations of phosphorous acid and copper ions by creating a chemical environment where both can coexist at high concentrations without precipitating, thereby maintaining both efficacy and stability.
Solution Approach 2:
The patent uses composite materials by formulating a specific combination of basic copper carbonate or sulfate, phosphorous acid, and potassium carbonate in defined ratios. This composite system creates chemical compatibility between the components, where the basic copper compound and phosphorous acid work synergistically for disease control while potassium carbonate maintains pH stability, preventing precipitate formation even at high concentrations.
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 stable compositions effectively control various fungal and bacterial plant pathogens, demonstrating improved shelf life and efficacy in disease management.
Implementation Method 1
aqueous compositions comprising copper ions, phosphorous acid and/or a salt thereof and various amines were not stable at low pH (1-3). In contrast, certain compositions having a pH of from about 6-10 were stable
Implementation Method 2
Mixtures containing high amounts of phosphorous acid in combination with significant amounts of dissolved copper ions near neutral pH may be difficult to stabilize
Data Source
AI summary
The present application relates to aqueous compositions for controlling a plant disease caused by a phytopathogenic organism, to methods of preparing such compositions and to uses of such compositions, for example for controlling a plant disease caused by a phytopathogenic organism. The aqueous compositions comprise copper ions, phosphorous acid and/or a salt thereof and an effective amount of an amine selected from an alkylamine, an alkanolamine and mixtures thereof. The pH of the compositions is from about 6 to about 10.