HFO-1234ze and HFO-1234yf compositions and processes for producing and using the compositions
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Solution Overview
Problem
Existing processes for producing HFO-1234ze and HFO-1234yf refrigerants require additional purification or separation steps to remove excess Z-isomer, which are costly and inefficient.
Innovation Solution
A dehydrofluorination process using a fluorinated Cr2O3 or Cr/Ni on fluoride alumina catalyst in the gas phase, optionally with an oxygen-containing gas, to produce near azeotropic compositions of HFO-1234ze(E) and HFO-1234yf, minimizing the need for separation steps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If catalytic dehydrofluorination of HFC-245fa is used to produce HFO-1234ze, then HFO-1234ze can be produced, but a mixture of Z-isomer and E-isomer is formed requiring additional separation steps
Solution Approach 1:
The patent changes the reaction parameters by using a specific catalyst system (fluorinated Cr2O3 or Cr/Ni on fluoride alumina) and gas-phase dehydrofluorination conditions to produce near azeotropic compositions that minimize Z-isomer formation, thereby reducing the need for separation steps
Solution Approach 2:
The patent converts the typically harmful Z-isomer byproduct into a beneficial near azeotropic composition with HFO-1234yf, where the presence of small amounts of Z-isomer and HFO-1234yf actually creates a stable refrigerant blend that requires minimal purification
2Productivity
If liquid phase dehydrofluorination using aqueous caustic is used, then HFO-1234ze can be produced, but 13% to 15% Z-isomer is typically formed requiring additional processing
Solution Approach 1:
The patent replaces the liquid-phase aqueous caustic system with a gas-phase catalytic dehydrofluorination process using fluorinated Cr2O3 or Cr/Ni on fluoride alumina catalyst, which provides better control over isomer composition and eliminates the need for additional isomerization or conversion steps
Solution Approach 2:
The patent changes the physical state from liquid-phase to gas-phase reaction and modifies the chemical environment from aqueous caustic to fluorinated catalyst surface, resulting in improved isomer selectivity and reduced Z-isomer formation
3Manufacturing precision
If separation of Z-isomer from E-isomer is performed, then pure E-isomer can be obtained, but additional isomerization or conversion steps are required adding cost
Solution Approach 1:
The patent accepts the presence of Z-isomer as an inherent part of the product mixture and converts it into a beneficial component by forming a near azeotropic composition with HFO-1234yf, which is stable and effective as a refrigerant blend, thereby eliminating costly isomerization or conversion steps
Solution Approach 2:
The patent creates a multi-component refrigerant blend where HFO-1234ze(E), HFO-1234ze(Z), and HFO-1234yf all serve functional roles in the final refrigerant composition, making the presence of Z-isomer irrelevant to product performance while simplifying the manufacturing process
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 near azeotropic compositions with minimal Z-isomer content, ensuring efficient production and reducing the need for additional purification steps, while maintaining low ozone depletion and global warming potential.
Implementation Method 1
A dehydrofluorination process using a fluorinated Cr2O3 or Cr/Ni on fluoride alumina catalyst in the gas phase
Data Source
AI summary
A fluoropropene composition comprising Z-1,3,3,3-tetrafluoropropene, E‑1,3,3,3‑tetrafluoropropene, 2,3,3,3-tetrafluoropropene, and optionally 1,1,1,3,3‑pentafluoropropane wherein the 2,3,3,3-tetrafluoropropene being present in an amount of 0.001 to 1.0%. A method of producing the fluoropropene, methods for using the fluoropropene and the composition formed are also disclosed.