Ammonium Dinitramide Synthesis via Acetone-Water Solvent
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Solution Overview
Problem
Current methods for producing ammonium dinitramide (ADN) face challenges such as potassium contamination, which is difficult and expensive to remove, and the formation of guanylurea sulfate (GUS) that slows down reaction rates and can drive reactions backwards, reducing yields.
Innovation Solution
Reacting guanylurea dinitramide (GUDN) with ammonium sulfate in a solution of acetone and water, which increases GUDN solubility, reduces water usage by up to 70%, and facilitates stable precipitation of GUS, allowing for higher yields and easier filtration, while operating at lower temperatures and avoiding azeotropes with water.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If potassium hydroxide is used to produce potassium dinitramide, then ADN can be produced through ion exchange with ammonium sulfate, but potassium contamination remains in the product which is difficult and expensive to remove
Solution Approach 1:
The invention extracts and removes potassium from the system by replacing potassium hydroxide with ammonium hydroxide as the base reagent. This eliminates the introduction of potassium ions that would contaminate the ADN product, thereby achieving high purity without requiring additional removal steps.
Solution Approach 2:
The invention introduces ammonium hydroxide as an intermediary substance that facilitates the formation of ADN without introducing contaminating cations. The ammonium ion serves as a temporary mediator that can be easily removed or converted, leaving pure ADN product.
2Productivity
If guanylurea sulfate is formed as a byproduct in water or water-alcohol solution, then the reaction can proceed, but the soluble GUS slows down the reaction rate and can drive the reaction backwards
Solution Approach 1:
The invention utilizes phase transition by changing the solvent system to acetone-water, which causes guanylurea sulfate to precipitate out of solution as a solid phase. This removal from the liquid phase prevents it from interfering with the reaction equilibrium and drives the reaction forward to completion.
Solution Approach 2:
The invention changes the solvent composition parameter from water or water-alcohol to acetone-water mixture. This parameter change fundamentally alters the solubility characteristics, causing GUS to precipitate while maintaining reactant solubility, thereby improving both reaction rate and yield.
3Ease of manufacture
If large amounts of water are used in the reaction mixture, then the reaction can proceed with current methods, but removal of water from the product is a main contributor to production cost and environmental impact
Solution Approach 1:
The invention changes the solvent parameter from water-based to acetone-based mixture. Acetone has lower boiling point and different evaporation characteristics compared to water, reducing the energy required for solvent removal and decreasing environmental impact from water discharge.
Solution Approach 2:
The invention uses acetone as a substitute solvent that copies the necessary solvent functions (dissolving reactants, facilitating reaction) but with superior properties for ease of removal and reduced environmental burden compared to water.
4Ease of manufacture
If alcohols are used as solvents in current processes, then the reaction can proceed, but alcohols form azeotropes with water upon evaporation making recycling difficult
Solution Approach 1:
The invention employs acetone as a disposable-like solvent that can be easily evaporated and removed without requiring complex recycling infrastructure. While acetone may be replaced rather than recycled in some implementations, this eliminates the need for sophisticated azeotropic distillation equipment.
Solution Approach 2:
Acetone serves as an intermediary solvent that performs the necessary dissolving and reaction facilitation functions but can be easily separated from the final product through simple evaporation, unlike alcohol-water azeotropes that require complex separation equipment.
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
This method achieves yields close to 90% ADN with reduced water consumption, lower energy costs, and improved process efficiency by stabilizing GUS precipitation and allowing ADN to remain in solution, enhancing safety and reducing environmental impact.
Implementation Method 1
The acetone increases the solubility of GUDN, which increases the yield for a certain volume of reaction mixture
Implementation Method 2
GUS is poorly soluble in acetone and in aqueous acetone. The use of acetone results in a stable precipitation of GUS, which ensures that the reaction proceeds to a high yield
Implementation Method 3
GUDN is reacted with AS in a reaction solution of acetone and water and ADN is formed in the reaction solution through an ion exchange reaction
Implementation Method 4
Acetone does not, in difference from alcohols that are used in previously known processes, form azeotropes with water upon evaporation. No azeotropes and a low boiling point of acetone make it easy to recycle acetone by ordinary distillation
Data Source
AI summary
The invention concerns a method for making ammonium dinitramide from guanylurea dinitramide in one single process step. Guanylurea dinitramide is reacted with an ammonium sulfate in a reaction solution comprising water and acetone and an ion exchange gives ammonium dinitramide. By using acetone the yield is increased compared to known processes as formed guanylurea sulfate is poorly soluable in a water-acetone solution and precipitates, while guanylurea dinitramide has higher solubility in the solution than in only water. The guanylurea sulfate precipitate formed in the reaction solution that contains acetone is less sticky than if formed in water or in a water-alcohol solution and therefore easier to filter off. The use of acetone also allows lower process temperatures to be used than in previously known methods for producing guanylurea dinitramide. Conclusively, the method gives a higher yield, demands considerable smaller amounts of solvent and allows lower process temperatures to be used than in any formerly known process.