NBPT Solubility in Alkylene Glycol Ether Solvents

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Solution Overview

Problem

The use of N-(n-butyl) thiophosphoric triamide (NBPT) as a urease inhibitor in fertilizers faces challenges due to its difficulty in solubilization in concentrated solutions and its instability when exposed to water, leading to decomposition and handling issues, including stickiness and caking of urea-based granular fertilizers.

Innovation Solution

A composition comprising NBPT combined with alkylene glycol alkyl ether solvents, which enhances solubility, stability, and reduces health risks, allowing for improved handling and storage of urease inhibitors in agricultural applications, while avoiding the use of potentially hazardous solvents like N-methylpyrrolidone and polyvinylpyrrolidone.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If NBPT is combined with water or hydroxyl-containing solvents to improve solubility, then solubility is enhanced, but stability deteriorates due to decomposition

Engineering Contradiction:

Improvesolubility of NBPTVSAvoidstability of NBPT

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

The patent changes the chemical parameter of the solvent system by selecting alkylene glycol alkyl ethers with specific molecular structures (containing ether oxygens and hydroxyl groups in controlled positions) that provide solubility without triggering NBPT decomposition. This parameter change resolves the contradiction by finding a solvent composition that satisfies both solubility and stability requirements.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent uses alkylene glycol alkyl ethers as intermediary substances that mediate between NBPT and water. These ethers act as co-solvents that facilitate NBPT dissolution while protecting it from direct contact with water and hydroxyl groups that would cause decomposition, thus resolving the solubility-stability contradiction.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Ease of manufacture

If concentrated solutions of NBPT are prepared to reduce transportation costs, then economic efficiency is improved, but solubility deteriorates due to precipitation

Engineering Contradiction:

Improveeconomic efficiencyVSAvoidsolubility of NBPT

Core Design Contradiction:

Ease of manufactureVSQuantity of substance

Solution Approach 1:

The patent modifies the solvent composition parameters by using specific ratios of alkylene glycol alkyl ethers combined with water, creating a solvent system with optimized solubilizing capacity that maintains NBPT in solution at high concentrations without precipitation, thus achieving both economic efficiency and solubility.

Inventive Principle:

Principle #35Parameter changes

3Quantity of substance

If traditional solvents like NMP or PVP are used to improve solubility, then solubility is enhanced, but safety deteriorates due to health risks

Engineering Contradiction:

Improvesolubility of NBPTVSAvoidhealth risks

Core Design Contradiction:

Quantity of substanceVSObject-affected harmful factors

Solution Approach 1:

The patent replaces expensive and hazardous solvents (NMP, PVP) with safer, more environmentally friendly alkylene glycol alkyl ethers that are biodegradable and have lower toxicity. This substitution maintains solubility performance while eliminating health risks, resolving the contradiction between solubility enhancement and safety.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

4Reliability

If NBPT is stored in aqueous solutions to maintain stability, then stability is improved, but handling deteriorates due to stickiness and caking

Engineering Contradiction:

Improvestability of NBPTVSAvoidhandling properties

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The patent adjusts the solvent system parameters by controlling the ratio of alkylene glycol alkyl ether to water and selecting specific ether chain lengths, which modifies the physical properties of the solution to prevent stickiness and caking during storage and handling while maintaining NBPT stability.

Inventive Principle:

Principle #35Parameter changes

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 alkylene glycol alkyl ether solvent system improves the stability and solubility of NBPT, reducing decomposition and handling issues, providing a safer, more effective, and cost-efficient urease inhibitor formulation for agricultural use, with enhanced resistance to solidification at low temperatures and improved miscibility with urea-based fertilizers.

Implementation Method 1

A composition comprising N-(n-butyl) thiophosphoric triamide and an alkylene glycol alkyl ether solvent

Methodology Applied

Scientific EffectSolvation: Solvation

Data Source

PatentUS9199884B2Liquid compositions containing urease inhibitors and glycol alkyl ethers and methods of making a use thereof

Publication Date: 2015.12.01 KOCH AGRONOMIC SERVICES LLC

AI summary

The present invention provides improved solvent systems for the preparation of liquid formulations of urease or nitrification inhibitors, specifically NBPT, comprising alkylene glycol alkyl ethers. The solvent systems provided good solubility of the urease inhibitor as well as at least one of improved stability, lower flammability, lower toxicity, improved cold temperature storage, improved handling, improved adsorption onto and/or solubility with solid media such as UFP or urea. Methods of making and using the compositions are also provided.