Propylene Oxide Purification via Distillation and Amine Reaction
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Solution Overview
Problem
Current methods for purifying propylene oxide are inefficient, leading to the accumulation of toxic reaction products and reagents in the recycling acetonitrile solvent stream, and require high amounts of expensive ion exchange resins, while failing to selectively separate carbonyl compounds based on their separability.
Innovation Solution
A process involving a stream of propylene oxide, acetonitrile, water, and a carbonyl compound is subjected to distillation, followed by reaction with an amino compound, and subsequent distillation to separate propylene oxide efficiently, avoiding pollution and reducing reagent consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional distillation methods are used to separate propylene oxide from carbonyl compounds, then separation is achieved, but toxic reaction products accumulate in the recycling solvent stream
Solution Approach 1:
The distillation process is segmented into multiple sections with different functions: a first section performs initial separation, while a second section specifically removes carbonyl compounds. This segmentation allows each section to be optimized for its specific separation task, preventing toxic accumulation while maintaining high purification efficiency.
Solution Approach 2:
An intermediary substance (amine compound) is introduced to react with carbonyl compounds forming intermediate products that are easier to separate. This intermediary enables selective removal of carbonyl compounds without affecting propylene oxide, thus preventing toxic accumulation in the recycling stream.
2Manufacturing precision
If high amounts of ion exchange resins are used to remove carbonyl compounds, then purification is improved, but reagent consumption and cost increase
Solution Approach 1:
The method changes the chemical parameters by using amine compounds that form reversible intermediates with carbonyl compounds. This allows for selective removal with much lower reagent consumption compared to ion exchange resins, while maintaining high purification quality through controlled reaction conditions.
Solution Approach 2:
The amine compound is applied locally in the second distillation section where carbonyl compounds concentrate. This localized application achieves effective purification with minimal reagent consumption, avoiding the need for large quantities required by ion exchange methods.
3Productivity
If conventional single-stage distillation is used, then process simplicity is maintained, but separation efficiency for carbonyl compounds is insufficient
Solution Approach 1:
The distillation process is divided into two functional sections: the first section handles bulk separation of propylene oxide from the reaction mixture, while the second section specifically targets carbonyl compound removal. This segmentation achieves high separation efficiency without requiring complex multi-column systems.
Solution Approach 2:
The first distillation section performs preliminary separation to concentrate carbonyl compounds in a specific stream before the second section applies the amine compound for selective removal. This preliminary action simplifies the overall process by pre-concentrating the target compounds, reducing the complexity of the purification step.
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 process effectively separates propylene oxide from carbonyl compounds like acetone and propionaldehyde, minimizing the accumulation of toxic substances and reducing reagent usage, thereby enhancing purification efficiency and environmental safety.
Implementation Method 1
separating propylene oxide from the stream S0 by distillation, comprising (ii.1) subjecting the stream S0 to distillation conditions in a first distillation unit
Implementation Method 2
reacting the carbonyl compound comprised in the side stream S1b with an organic compound comprising an amino group -NH2, wherein a reaction product of the organic compound comprising a carbonyl group and the organic compound comprising an amino group is obtained
Implementation Method 3
separating propylene oxide from the reaction product of the organic compound comprising a carbonyl group and the organic compound comprising an amino group in a second distillation unit
Data Source
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AI summary
The present invention is related to a process for purifying propylene oxide, comprising (i) providing a stream SO comprising propylene oxide, acetonitrile, water, and an organic compound comprising a carbonyl group -C(=O)-, wherein said organic compound comprising a carbonyl group -C(=O)- comprises one or more of acetone and propionaldehyde; (ii) separating propylene oxide from the stream SO by distillation, comprising (11.1) subjecting the stream S0 to distillation conditions in a first distillation unit, obtaining a gaseous top stream S1 c which is enriched in propylene oxide compared to the stream S0, a liquid bottoms stream S1a which is enriched in acetonitrile and water compared to the stream S0, and a side stream S1b comprising propylene oxide which is enriched in the carbonyl compound compared to the stream S0; (11.2) reacting the carbonyl compound comprised in the side stream S1b with an organic compound comprising an amino group -NH2 obtaining a reaction product of the organic compound comprising a carbonyl group and the organic compound comprising an amino group; (11.3) separating propylene oxide from the reaction product of the organic compound comprising a carbonyl group and the organic compound comprising an amino group in a second distillation unit, obtaining a gaseous top stream S3a which is enriched in propylene oxide and a liquid bottoms stream S3b which is enriched in the reaction product of the organic compound comprising a carbonyl group and the organic compound comprising an amino group; (11.4) introducing the top stream S3a which is enriched in propylene oxide propylene oxide into the first distillation unit.