Alkanediol Acylation Route for Safe Mononitrate Production
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Solution Overview
Problem
Existing methods for producing ω-nitrooxy-C3-10 alkane-1-ols, such as 3-nitrooxypropanol, face challenges in industrial scale production due to poor selectivity, safety concerns with explosive organic nitrates, and increased processing costs in multi-step processes, necessitating a safer and more economical solution.
Innovation Solution
A three-step process involving acylation of α,ω-alkanediol with an acylating agent, followed by nitrate ester formation and hydrolysis, with recycled reaction components and controlled molar ratios, using inert solvents and continuous reactors to enhance safety and yield.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If direct nitrate ester formation of α,ω-alkanediols is used, then the production route is simplified, but selectivity deteriorates and safety worsens due to explosive dinitrate formation
Solution Approach 1:
The patent divides the acylation process into multiple stages with intermediate separation. The acylation reaction is segmented into: (i) initial acylation to form monoacylates and diacylates, (ii) separation of diacylates for recycle, and (iii) continued acylation to reach high conversion. This segmentation prevents runaway reactions and improves safety while maintaining selectivity.
Solution Approach 2:
The patent introduces an intermediary separation and recycling step for diacylated products. The diacylates are separated from the reaction mixture and recycled back to the acylation reactor, acting as an intermediary that prevents their accumulation and potential decomposition while improving overall process selectivity and safety.
2Manufacturing precision
If interim protection by acetylation followed by nitrate ester formation is used, then safety and selectivity improve, but productivity deteriorates due to additional reaction steps
Solution Approach 1:
The patent recovers and recycles unreacted starting materials and intermediates from the acylation reaction. The separation unit operably connected to the acylation reactor enables recovery of unreacted α,ω-alkanediol and monoacylates, which are recycled back to the reactor. This reduces material loss and improves overall yield while maintaining the safety benefits of the stepwise process.
Solution Approach 2:
The patent implements a continuous process where the acylation reactor and separation unit operate in continuous mode. The recycled streams are continuously fed back to the reactor, maintaining continuous useful action and improving productivity compared to batch processes with multiple discrete steps.
3Quantity of substance
If traditional acylation with water removal is used, then reaction equilibrium shifts forward, but loss of substance increases due to evaporative losses
Solution Approach 1:
The patent recovers water from the acylation reaction system through the separation unit and recycles it back to the reactor. This water recovery and recycling approach maintains the forward shift of reaction equilibrium (improving conversion) while minimizing evaporative losses by capturing and reusing the water that would otherwise be lost.
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 high yields of ω-nitrooxy-C3-10alkane-1-ols while maintaining reaction stability and ensuring process safety, allowing for quantitative recovery of reactants and solvents.
Implementation Method 1
A process for the acylation of an α,ω-alkanediol, preferably 1,3-propanediol, with an acylation agent (acylation reaction)
Implementation Method 2
nitrate ester formation of the resulting α,ω-C3-10alkanediol monoacylate with a nitrating agent to form a α,ω-C3-10alkanediol mononitrate monoacylate
Implementation Method 3
hydrolysis of the acyl group to obtain the respective α,ω-C3-10alkanediol mononitrate
Data Source
AI summary
The invention relates to a safe and efficient process for the for the acylation of an α,ω-alkanediol, which can be used in the manufacture of ω-nitrooxy-C3-10alkane-1-ols. The process is safer to operators and allows to obtain advantageous yields on industrial scale.