HFIP Distillation with Protic Solvent for Tetrahydroquinoline Separation
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Solution Overview
Problem
The separation of hexafluoroisopropanol from 4-substituted 1,2,3,4-tetrahydroquinolines is difficult due to hydrogen bonding, leading to inefficient recycling and the formation of undesired decomposition products at harsh distillation conditions.
Innovation Solution
A process involving the addition of a protic solvent such as water, methanol, or ethanol to the mixture before distillation allows for efficient separation of hexafluoroisopropanol from 4-substituted 1,2,3,4-tetrahydroquinolines, achieving a residual hexafluoroisopropanol content below 10% by weight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If HFIP is recovered by conventional distillation methods, then HFIP can be obtained from reaction mixtures, but the process requires excessive energy input and time due to the high boiling points and close boiling point differences of the components
Solution Approach 1:
The patent introduces a solvent system (comprising ethyl acetate, n-heptane, and water in specific ratios) as an intermediary medium to enable extraction distillation. This solvent system selectively interacts with HFIP and the tetrahydroquinoline derivative, creating solvates that have different volatilities from the original components, thereby facilitating separation at lower energy input compared to conventional distillation of the pure components.
Solution Approach 2:
The process utilizes phase transition phenomena through extraction distillation, where the solvent system creates soluble complexes that change the volatility characteristics of HFIP. By controlling the phase behavior of the solvent mixture and the solute-solvent complexes, the patent achieves separation at temperatures lower than the boiling points of the original components, reducing energy consumption.
2Manufacturing precision
If conventional distillation is used to separate HFIP from tetrahydroquinoline derivatives, then separation can be achieved, but the process is time-consuming due to the high boiling points and close boiling point differences
Solution Approach 1:
The solvent system acts as a mediator that creates soluble complexes with different volatility characteristics. This intermediary approach allows for faster separation by creating larger volatility differences between the complexed HFIP and the tetrahydroquinoline derivative, enabling quicker distillation cycles while maintaining high separation purity.
Solution Approach 2:
The patent changes the physical-chemical parameters of the mixture by introducing a multi-component solvent system. This changes the effective boiling behavior of the components through solvate formation, creating more favorable volatility differences that accelerate the distillation process while maintaining separation efficiency.
3Reliability
If conventional distillation methods are applied to HFIP mixtures, then HFIP can be recovered, but the process is economically unattractive due to high energy consumption and long processing times
Solution Approach 1:
The solvent system serves as an economically beneficial intermediary that enables recovery of HFIP at lower energy costs and faster processing rates. The specific composition of ethyl acetate, n-heptane, and water is chosen to optimize both the separation efficiency and the economic feasibility of the process.
Solution Approach 2:
By utilizing extraction distillation with controlled phase transitions of the solvent system, the patent achieves reliable HFIP recovery through a process that is economically attractive due to reduced energy consumption and shorter processing times compared to conventional distillation 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 effectively recovers hexafluoroisopropanol to below 0.1% by weight, maintaining the stability of 4-substituted 1,2,3,4-tetrahydroquinolines and avoiding decomposition.
Implementation Method 1
Process for distillative recovery of 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP) from mixtures with 4- substituted 1,2,3,4-tetrahydroquinolines
Implementation Method 2
heating the mixture to a temperature of from 50° C. to 100° C. and distilling off the HFIP
Data Source
AI summary
The invention relates to a process for distillative recovery of 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP) from an initial mixture comprising 1,1,1,3,3,3-hexafluoro-2-propanol and at least one 4-substituted 1,2,3,4- tetrahydroquinoline, wherein a protic solvent selected from the group consisting of water, alcohols having a boiling point at 1 bar of 115 °C or less, and mixtures thereof is added to the initial mixture to obtain a distillation mixture, and the distillation mixture is subjected to distillation.