Azeotropic Distillation for 2-Alkoxyethanol Removal
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Solution Overview
Problem
Current methods for separating 2-alkoxyethanol from its azeotropic mixture with (2-alkoxyethyl) vinyl ether are inefficient, leading to decreased vinyl ether yield and requiring excessive energy and solvent use, especially for high-boiling vinyl ethers where boiling point differences are small, making it difficult to predict optimal azeotropic solvents for specific systems.
Innovation Solution
The use of specific azeotropic solvents such as alkanes and cycloalkanes with 7 to 8 carbon atoms, like normal heptane and isooctane, in azeotropic distillation to efficiently separate 2-alkoxyethanol from mixtures with (2-alkoxyethyl) vinyl ether, while minimizing vinyl ether loss and optimizing yield.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If distillation is performed under different pressure conditions to separate azeotropic mixture, then separation is achieved, but the yield of vinyl ether decreases because the main component distilled from the upper portion is vinyl ether
Solution Approach 1:
The patent introduces a third component (azeotropic solvent) as an intermediary substance that forms an azeotropic mixture with the alcohol to enable separation. This mediator allows the alcohol to be removed without directly distilling the vinyl ether, thus maintaining high yield while achieving purification.
Solution Approach 2:
The patent changes the compositional parameter of the mixture by adding a third component (azeotropic solvent) to alter the azeotropic behavior. This parameter change enables selective removal of alcohol while preserving vinyl ether in the bottom product, resolving the contradiction between separation purity and yield.
2Manufacturing precision
If alkali metal salt is added to destroy azeotropy, then separation becomes possible, but alkali metal alcoholate precipitates as solid in distillation column making continuous process difficult
Solution Approach 1:
The patent employs a water-soluble organic compound as a temporary, disposable azeotropic agent that can be easily removed from the system. This disposable mediator forms the necessary azeotropic mixture during distillation but does not accumulate or precipitate, enabling continuous operation unlike permanent additives.
Solution Approach 2:
The patent changes the chemical nature of the azeotropic agent from alkali metal salt (which forms insoluble alcoholates) to water-soluble organic compounds (which remain soluble). This parameter change in the agent's solubility characteristics prevents precipitation and enables continuous process operation.
3Manufacturing precision
If water is used as extraction solvent for distillation, then separation is achieved, but vinyl ether is lost by hydrolysis and yield decreases
Solution Approach 1:
The patent uses a water-soluble organic compound as an intermediary extraction solvent that is immiscible with vinyl ether. This mediator allows selective extraction of alcohol while leaving vinyl ether in the organic phase, preventing hydrolysis loss that occurs with water as the extraction solvent.
4Manufacturing precision
If glycol or glycol monoether containing water is used as extraction solvent, then distillation is enabled, but large amount of energy is required to recover and reuse raw material alcohol
Solution Approach 1:
The patent changes the solvent system from water-containing glycol/glycol monoether to a water-soluble organic compound that forms a two-phase system. This parameter change in solvent composition enables easier separation and lower energy consumption for alcohol recovery and reuse.
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 allows for easy and efficient removal of 2-alkoxyethanol, maintaining high vinyl ether yield and purity, and is suitable for industrial use due to the thermal stability and low toxicity of the solvents used.
Implementation Method 1
adding one or more azeotropic solvents selected from the group consisting of alkanes having 7 to 8 carbon atoms and cycloalkanes having 7 to 8 carbon atoms to a mixture containing the 2-alkoxyethanol and the (2-alkoxyethyl) vinyl ether, and subjecting the resulting mixture to azeotropic distillation
Implementation Method 2
an azeotropic mixture of water and vinyl ether is obtained from the top of the column, and separated into an oil phase and an aqueous phase by a decanter
Data Source
AI summary
To provide a method capable of easily and efficiently removing a 2-alkoxyethanol from a mixture containing the 2-alkoxyethanol and a (2-alkoxyethyl) vinyl ether while suppressing a decrease in the yield of (2-alkoxyethyl) vinyl ether.A method for removing a 2-alkoxyethanol, including the step of adding one or more azeotropic solvents selected from the group consisting of alkanes having 7 to 8 carbon atoms and cycloalkanes having 7 to 8 carbon atoms to a mixture containing the 2-alkoxyethanol represented by the following formula (1)R—O—CH2CH2OH (1)where R represents an alkyl group having 1 to 4 carbon atoms, and a (2-alkoxyethyl) vinyl ether represented by the following formula (2)R—O—CH2CH2O—CH═CH2 (2)where R has the same meaning as R in the formula (1),and subjecting the resulting mixture to azeotropic distillation.