Vicinal Diol Separation via Acetalization and Hydrolysis
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Solution Overview
Problem
There is a lack of cost-effective methods for separating mixtures of polyols, particularly vicinal diols with close boiling points, which makes conventional distillation ineffective due to similar boiling points.
Innovation Solution
The method involves reacting the polyol mixture with an aldehyde or ketone acetalization agent to form acetal reaction products with wider boiling point differences, allowing for easier separation through distillation or phase partitioning, followed by hydrolysis to recover the purified polyols.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional distillation is used to separate polyols, then the separation process is simple, but the separation is ineffective due to similar boiling points
Solution Approach 1:
The patent changes the chemical parameters of the polyol mixture by converting it into acetal derivatives through reaction with aldehydes or ketones. This transformation fundamentally alters the boiling point characteristics of the components, creating sufficient boiling point differences that enable effective distillation separation. The parameter change approach resolves the contradiction by modifying the substance properties rather than changing the separation method itself.
Solution Approach 2:
The patent introduces acetalization agents (aldehydes or ketones) as intermediary substances that temporarily transform the polyol components into separable acetal derivatives. These intermediaries act as mediators that enable separation by creating differential volatility, after which they are removed through hydrolysis to recover the original polyols. This intermediary approach allows simple distillation to achieve high purity separation.
2Manufacturing precision
If acetalization reaction is performed to form separable products, then separation becomes easier, but additional reaction steps are required
Solution Approach 1:
The patent implements continuous operation where the acetalization reaction, distillation separation, and hydrolysis steps are conducted in a continuous manner rather than batch processing. This continuity maintains productive action throughout the process, minimizing idle time and maximizing throughput. The useful action of separation is maintained continuously through the integrated process design.
Solution Approach 2:
The patent merges multiple unit operations into an integrated process flow where acetalization, distillation, and hydrolysis are combined in sequence. By merging these steps into a coordinated process rather than separate batch operations, the overall productivity is improved while maintaining the separation benefits of the acetalization approach.
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 approach enables the cost-effective separation of polyols with close boiling points by converting them into more easily separable acetal products, which can then be hydrolyzed back to their original form, achieving high purity and efficiency.
Implementation Method 1
forming in the reactor via an acid-catalyzed reaction: (i) a first acetalization product comprising a reaction product between the first polyol reactant and the acetalization reactant
Implementation Method 2
The polyol mixture is reacted with an aldehyde or ketone acetalization agent to form one or more corresponding acetal reaction products
Implementation Method 3
separating a reactor product mixture comprising the first acetalization product, the second acetalization product, and the water into (i) a water-immiscible product comprising the first acetalization product and the second acetalization product, and (ii) an aqueous product comprising the water
Implementation Method 4
hydrolyzing the first product to form the first polyol reactant from the first acetalization product; and hydrolyzing the second product to form the second polyol reactant from the second acetalization product
Implementation Method 5
allowing for easier separation through distillation or phase partitioning
Data Source
AI summary
The disclosure relates to methods for separating mixtures of polyols, in particular mixtures of two of more different vicinal diols having close boiling points, thus making them difficult or impossible to separate using conventional distillation techniques. The polyol mixture is reacted with an aldehyde or ketone acetalization agent to form one or more acetals as corresponding acetalization reaction products. The acetalization reaction products are more easily separable either from each other (such as via distillation) or from an unreacted vicinal diol (such as via extraction, settling, or other phase separation). After separation, hydrolysis is performed on the acetalization reaction products to recover the vicinal diols as separate, purified components. The methods provide cost-effective processes for separating different polyols originally formed in admixture.