Extractive Distillation for cis-1,1,1,4,4,4-Hexafluoro-2-butene Purification
Solution Overview
Problem
Conventional distillation methods are ineffective for separating cis-1,1,1,4,4,4-hexafluoro-2-butene from chlorofluoroolefins due to the formation of azeotropes and similar boiling points, leading to incomplete separation and contamination issues in the production of hydrofluoroolefins.
Innovation Solution
An extractive distillation process using a C6 to C14 linear or branched alkane, cyclic alkane, alkene, diene, chloroalkane, or other specified compounds as extractive agents to alter the relative volatility of cis-1,1,1,4,4,4-hexafluoro-2-butene and chlorofluoroolefins, allowing for their effective separation in a distillation column.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional distillation is used to separate cis-1,1,1,4,4,4-hexafluoro-2-butene from chlorofluoroolefins, then the process is simple and equipment is minimal, but complete separation is impossible due to azeotrope formation and similar boiling points
Solution Approach 1:
An extractive agent is introduced as an intermediary substance into the distillation system. This agent selectively interacts with chlorofluoroolefin impurities through complexation or solvation, altering their volatility characteristics. The extractive agent acts as a mediator that enables separation of azeotropic mixtures by creating temporary chemical associations that change the relative volatility between desired product and impurities, allowing complete separation that would otherwise be impossible with conventional distillation alone.
Solution Approach 2:
The relative volatility parameter of the mixture components is changed by introducing the extractive agent. This chemical modification of the system changes the vapor-liquid equilibrium characteristics, creating sufficient volatility difference between cis-1,1,1,4,4,4-hexafluoro-2-butene and chlorofluoroolefin impurities. The extractive agent temporarily modifies physicalchemical parameters of the impurities during distillation, enabling separation at ordinary boiling points without requiring extreme conditions or complex multi-stage processes.
2Productivity
If conventional distillation is used, then energy consumption is low and process is simple, but separation efficiency is insufficient and product contamination occurs
Solution Approach 1:
The extractive agent serves as a chemical intermediary that enhances separation efficiency by selectively binding to impurity molecules. This intermediary mechanism creates stronger interaction differences between product and impurity, amplifying the separation effect per theoretical stage. The extractive agent enables more efficient mass transfer and sharper separation fronts, achieving higher purity products with fewer distillation stages, thereby improving productivity without proportionally increasing energy consumption.
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 a high purity of cis-1,1,1,4,4,4-hexafluoro-2-butene by reducing chlorofluoroolefin concentrations to less than 1 ppm, overcoming the limitations of conventional distillation and enabling the production of environmentally friendly hydrofluoroolefins.
Implementation Method 1
An extractive distillation process using a C6 to C14 linear or branched alkane, cyclic alkane, alkene, diene, chloroalkane, or other specified compounds as extractive agents to alter the relative volatility of cis-1,1,1,4,4,4-hexafluoro-2-butene and chlorofluoroolefins, allowing for their effective separation in a distillation column.
Implementation Method 2
contacting said first mixture with at least one extractive agent, to form a second mixture; distilling said second mixture
Data Source
AI summary
A process for separating cis-1,1,1,4,4,4-hexafluoro-2-butene from a first mixture comprising cis-1,1,1,4,4,4-hexafluoro-2-butene and at least one chlorofluoroolefin is disclosed. The process involves the steps of contacting the mixture with at least one extractive agent, to form another mixture, distilling the mixture; and recovering cis-1,1,1,4,4,4-hexafluoro-2-butene substantially free of chlorofluoroolefin.