Chromium Oxyfluoride Catalyst for High Z/E Ratio HFC-1225ye
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Solution Overview
Problem
There is a need for new manufacturing processes for the production of tetrafluoropropenes and pentafluoropropenes, particularly with a high Z/E ratio, as existing methods do not efficiently produce the preferable Z isomer of 1,2,3,3-pentafluoropropene (HFC-1225ye) used as a refrigerant.
Innovation Solution
A process involving the dehydrofluorination of 1,1,1,2,2,3-hexafluoropropane using a chromium oxyfluoride catalyst with low alkali metal content, where the catalyst is prepared by treating Cr2O3 with HF or hydrofluorocarbons, and the product mixture is separated to achieve a high Z/E ratio of HFC-1225ye.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional chromium oxide catalysts are used for dehydrofluorination, then the reaction can proceed, but the Z/E ratio of HFC-1225ye is low
Solution Approach 1:
The patent applies parameter changes by modifying the catalyst composition parameters - specifically limiting alkali metal content to 2000 ppm or less and controlling fluorine-to-chromium ratio. This resolves the contradiction by adjusting chemical composition parameters to achieve high Z/E ratio (superior manufacturing precision) while maintaining a practical catalyst preparation process (acceptable ease of manufacture).
Solution Approach 2:
The patent applies local quality by creating specific active sites on the catalyst surface with controlled alkali metal distribution. The non-uniform distribution of alkali metals (kept at 2000 ppm or less) creates localized active sites that selectively promote Z-isomer formation, resolving the contradiction between achieving high Z/E ratio and maintaining simple catalyst preparation.
2Productivity
If trivalent chromium oxide catalyst is used, then dehydrofluorination reaction occurs, but production efficiency is insufficient
Solution Approach 1:
The patent applies composite materials by combining chromium oxide with controlled amounts of alkali metals (≤2000 ppm) and adjusting fluorine content. This creates a composite catalyst structure that enhances productivity through synergistic effects while maintaining reliability through the stable chromium oxide framework. The composite nature allows simultaneous achievement of high production efficiency and catalyst stability.
Solution Approach 2:
The patent applies parameter changes by optimizing the fluorine-to-chromium ratio and limiting alkali metal content to 2000 ppm or less. These parameter adjustments resolve the contradiction by creating a catalyst with enhanced activity (improved productivity) while the controlled composition maintains structural stability (preserved reliability).
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 produces HFC-1225ye with a high Z/E ratio, enhancing the efficiency of refrigerant production and meeting the demand for reduced global warming potential refrigerants.
Implementation Method 1
contacting 1,1,1,2,2,3-hexafluoropropane with a chromium oxyfluoride catalyst having an alkali metal content of 2000 ppm or less in a reactor to obtain a product mixture comprising 1,2,3,3,3-pentafluoropropene (HFC-1225ye)
Data Source
AI summary
A process is disclosed for making CF3CF=CHF. The process involves contacting at least one hexafluoropropane selected from the group consisting of CF3CF2CH2F and CF3CHFCHF2 with a chromium oxyfluoride catalyst in a reactor to obtain a product mixture comprising CF3CF=CHF, and recovering CF3CF=CHF from the product mixture. A process is disclosed for making CF3CH=CHF. The process involves contacting CF3CH2CHF2 with a chromium oxyfluoride catalyst in a reactor to obtain a product mixture comprising CF3CH=CHF, and recovering CF3CH=CHF from the product mixture. A process is disclosed for making CF3CF=CH2. The process involves contacting CF3CF2CH3 with a chromium oxyfluoride catalyst in a reactor to obtain a product mixture comprising CF3CF=CH2, and recovering CF3CF=CH2 from the product mixture.