Fluoroolefin Separation from HF via Liquid-Liquid Extraction
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Solution Overview
Problem
The separation of fluoroolefins from mixtures with hydrogen fluoride is challenging due to the formation of azeotropes, making existing methods like distillation and aqueous scrubbing ineffective, leading to waste production and high costs.
Innovation Solution
A liquid-liquid extraction process using extractants such as hydrocarbons, chlorocarbons, and perfluorocarbons to selectively separate fluoroolefins from hydrogen fluoride, with the extractant having a lower or higher density than the fluoroolefin-HF mixture, allowing for the recovery of pure fluoroolefin and hydrogen fluoride products.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If aqueous scrubbing is used to separate fluoroolefins from HF, then the separation effectiveness is improved, but large amounts of scrubbing solutions are required and excessive waste is produced
Solution Approach 1:
The patent changes the physical-chemical parameters of the extraction system by using organic solvents with specific properties (density different from fluoroolefin-HF mixture, appropriate solubility parameters) to achieve separation without the waste issues of aqueous scrubbing. The extractant is selected based on parameters like density, solubility, and chemical inertness to resolve the contradiction between effective separation and waste minimization.
2Reliability
If aqueous scrubbing is used to separate fluoroolefins from HF, then the separation effectiveness is improved, but additional equipment is needed to dry the wet fluoroolefin produced
Solution Approach 1:
The patent extracts HF from the fluoroolefin mixture using an organic extractant that preferentially dissolves HF, separating it into a distinct phase. This extraction approach avoids the wet product problem of aqueous scrubbing because the extractant can be easily separated from the fluoroolefin product, eliminating or reducing the need for drying equipment.
3Device complexity
If distillation is used to separate fluoroolefins from HF, then the separation process is simplified, but the method is ineffective due to azeotrope formation
Solution Approach 1:
The patent introduces an intermediary substance (extractant) that mediates the separation between fluoroolefins and HF. This extractant preferentially interacts with HF, forming an extract phase that separates from the fluoroolefin-rich raffinate phase, thereby achieving effective separation without the limitations of direct distillation of the azeotropic mixture.
4Device complexity
If decantation is used to separate fluoroolefins from HF, then the process is simple, but the separation is ineffective due to azeotrope formation
Solution Approach 1:
The patent employs an extractant as an intermediary that enables effective separation. The extractant is added to the fluoroolefin-HF mixture, where it preferentially dissolves HF, creating two immiscible phases that can be easily decanted. This maintains the simplicity of decantation while overcoming the ineffectiveness caused by azeotrope formation.
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 fluoroolefins from hydrogen fluoride, reducing waste and operational costs by using liquid-liquid extraction with specific extractants, enabling the recovery of high-purity products.
Implementation Method 1
The separation of fluoroolefins from these mixtures is not always easily accomplished because many fluoroolefins form an azeotrope with HF. Existing methods of distillation and decantation are very often ineffective for the separation of these compounds. Aqueous scrubbing may be effective, but requires the use of large amounts of scrubbing solutions and produces excessive waste and a wet product that must then be dried.
Data Source
AI summary
Disclosed is a process for separating fluoroolefin from a composition comprising HF and fluoroolefin, said process comprising extracting said composition with an extractant. Also disclosed is a composition comprising HF, at least one fluoroolefin, and at least one extractant.