NBPT Liquid Solvent Composition for Fertilizer Stability
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Solution Overview
Problem
Current urease inhibitors, particularly N-(n-butyl)thiophosphoric triamide (NBPT), face challenges such as instability due to moisture and temperature, poor solubility, and difficulty in homogeneous application on fertilizers, leading to inefficient ammonia reduction and environmental issues.
Innovation Solution
A liquid composition comprising 15-35 wt% NBPT, 25-45 wt% glycerine, and 30-50 wt% benzyl alcohol or N,N-dimethylacetamide as solvents, with a minor amount of acid blue dye, is developed to enhance stability and ease of application, ensuring low odor and safety while maintaining effectiveness as a urease inhibitor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If NBPT is used as a urease inhibitor, then ammonia release is reduced, but NBPT decomposes due to moisture and elevated temperatures
Solution Approach 1:
The patent introduces a solvent system as an intermediary medium to carry NBPT from the solid state to the application site. The solvent acts as a mediator that prevents direct contact between NBPT and moisture/heat while enabling delivery to the target location, thus resolving the contradiction between stability and effectiveness.
Solution Approach 2:
The patent changes the physical state of NBPT from solid to dissolved form in a solvent system. This parameter change (solid→liquid dissolution) allows NBPT to be applied in a stable, non-decomposing form while maintaining its urease inhibition activity, addressing both stability and effectiveness requirements.
2Object-generated harmful factors
If NBPT is applied directly to urea fertiliser, then urease activity is inhibited, but homogeneous coating is difficult to achieve due to poor water solubility
Solution Approach 1:
The solvent system serves as an intermediary that enables uniform distribution and coating of NBPT on fertiliser surfaces. By dissolving NBPT in the solvent, the patent achieves homogeneous coating that would be impossible with solid NBPT alone, thus resolving the contradiction between effectiveness and coating uniformity.
3Quantity of substance
If organic solvents are used to dissolve NBPT, then solubility is improved, but toxicity, volatility and flammability increase
Solution Approach 1:
The patent carefully selects and adjusts solvent parameters (type, concentration, molecular structure) to achieve NBPT dissolution while minimizing harmful properties. By optimizing these parameters, the patent resolves the contradiction between solubility and safety, finding a balance point where NBPT is sufficiently dissolved but harmful effects are minimized.
4Stability of the object's composition
If NBPT solutions are stored at sub-zero temperatures, then crystallisation is prevented, but manufacturing cost increases
Solution Approach 1:
The patent modifies the solvent system parameters (composition, concentration ratios, additive selection) to lower the crystallisation temperature of the NBPT solution. This parameter change allows storage at milder temperatures without crystallisation, reducing manufacturing and storage costs while maintaining solution stability.
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 composition achieves high stability at various temperatures and maintains NBPT levels within 0.5% during storage and application, effectively reducing urease activity and ammonia release, thus addressing the environmental and agronomic concerns associated with urea decomposition.
Implementation Method 1
it is necessary to use NBPT solutions in a suitably selected system of organic solvents... they should meet basic criteria such as low odour, high solubility and NBPT stability
Implementation Method 2
These compounds act by blocking three active sites of the urease enzyme by forming bonds with two nickel atoms and an oxygen atom from the carbamate bridge linking both metals, thereby preventing the urea molecule from reaching the nickel atom
Implementation Method 3
no adsorption on the surface of fertilisers constitutes a significant problem
Data Source
AI summary
A liquid composition for application on solid fertilisers, wherein the composition contains an active substance in the form of N-(n-butyl)thiophosphoric triamide, and a solvent system, and a dye and characterised in that the solvent system comprises an organic solvent from the triol group, and at least one co-solvent selected from benzyl alcohol and N,N-dimethylacetamide. A method of manufacture of the liquid composition, wherein the method comprises: • mixing the active substance and the solvent system at a temperature up to 40°C to dissolve the active substance, and then • adding the dye and stirring and heating at a temperature up to 40°C to dissolve the dye. A use of the liquid composition as an additive to amide nitrogen containing fertilisers.