Neutral Polymer Binder Synthesis Without Hazardous Diisocyanates
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Solution Overview
Problem
Existing methods for synthesizing neutral polymeric binding agents (NPBA) for energetic materials, such as composite solid propellants, involve hazardous diisocyanates, which are not compliant with REACH regulations and pose processing challenges.
Innovation Solution
A one-pot synthesis process using carbonyldiimidazole and propargylamine to produce a compound of formula (I), with specific reaction conditions and solvent choices to ensure compliance with REACH regulations and improve safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If diisocyanates are used to synthesize NPBA, then the synthesis follows conventional methods, but the process becomes hazardous and non-compliant with REACH regulations
Solution Approach 1:
The patent extracts and removes the hazardous diisocyanate component from the synthesis process, replacing it with carbonyldiimidazole and propargylamine. This substitution eliminates the harmful factors associated with diisocyanates while maintaining the ability to produce NPBA through an alternative chemical pathway that complies with REACH regulations.
Solution Approach 2:
The patent introduces carbonyldiimidazole as an intermediary reagent that facilitates the formation of isocyanate equivalents without using actual diisocyanates. This intermediary approach allows the synthesis to proceed through a safer chemical route, where carbonyldiimidazole reacts with hydroxyl groups to form imidazolidinone intermediates that subsequently react with propargylamine to yield the desired NPBA product.
2Object-affected harmful factors
If a multi-step synthesis process is used to avoid hazardous reagents, then safety improves, but the process complexity and purification difficulty increase
Solution Approach 1:
The patent merges multiple synthetic steps into a streamlined sequence using carbonyldiimidazole and propargylamine. The combination of these two reagents allows the synthesis to proceed through interconnected reactions that can be monitored and controlled in a unified manner, reducing the overall process complexity compared to traditional multi-step approaches while maintaining safety.
Solution Approach 2:
The patent utilizes parameter changes, specifically the use of excess propargylamine (1.5-6 equivalents), to drive the reaction to completion and simplify purification. By adjusting the stoichiometric parameters and using excess of one reagent, the process achieves quantitative yields and facilitates easier product isolation, thereby reducing process complexity.
3Reliability
If conventional NPBA synthesis is used, then the method is well-established, but the reagents are toxic and require complex purification
Solution Approach 1:
The patent employs reagents and intermediates that are easily disposable or easily removed from the final product. The use of carbonyldiimidazole and propargylamine generates byproducts that can be readily separated, and the excess reagents can be removed through simple purification steps, thereby reducing purification difficulty and substance loss.
Solution Approach 2:
By changing the reaction parameters to use excess propargylamine (1.5-6 equivalents), the patent ensures complete conversion of the polymer hydroxyl groups and simplifies the purification process. The excess propargylamine and its reaction byproducts can be easily removed, achieving quantitative yields with minimal purification steps compared to conventional methods.
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 process achieves quantitative yields, uses low-toxicity reagents, and facilitates easy purification, providing a safe and efficient method for producing NPBA suitable for energetic materials.
Implementation Method 1
the reaction of a compound of formula (II) with carbonyldiimidazole, in excess, optionally in the presence of a solvent to afford an intermediate compound of formula (III)
Implementation Method 2
the reaction of the compound obtained in step a) with an excess of propargylamine, optionally in the presence of a solvent
Data Source
AI summary
This disclosure relates to a process for the synthesis of a compound of formula (I): in which w, x, y, and z are as defined in the description. The process includes the reaction of a compound of formula (II): with carbonyldiimidazole, and the reaction of the resulting compound with propargylamine.