HFO-1234yf Production via Chromium Oxide Catalysis
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Solution Overview
Problem
Current processes for producing 2,3,3-tetrafluoropropene (HFO-1234yf) are inefficient, requiring expensive reagents, severe reaction conditions, and low yields, making them unsuitable for industrial-scale production.
Innovation Solution
A single-step process using a fluorine-containing propane, such as CF2ClCF2CH3, contacted with chromium oxides or iron fluorides in a gas phase, in the presence of oxygen and hydrogen fluoride, to produce HFO-1234yf with improved selectivity and yield.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If hydrogen fluoride is used in large excess (18 mol per mol of starting material) to prepare HFO-1234yf using chromium oxyfluoride, then the reaction can proceed, but the efficiency deteriorates due to poor atom economy and high reagent consumption
Solution Approach 1:
The patent changes the molar ratio parameter from the conventional 18:1 (HF:starting material) to a much lower ratio, achieving the same reaction efficiency with significantly reduced hydrogen fluoride consumption. This parameter optimization directly resolves the contradiction between productivity and substance loss.
2Ease of manufacture
If zinc is used as reagent in ethanol to produce HFO-1234yf in a single-step process, then the reaction proceeds, but the process becomes unsuitable for industrial-scale production due to high cost and large waste production
Solution Approach 1:
The patent replaces expensive zinc reagent with a catalyst system that can be used in small amounts and potentially regenerated. This substitution makes the process economically viable for industrial-scale production while maintaining ease of manufacture.
Solution Approach 2:
The catalytic system allows for potential recovery and reuse of the catalyst, reducing waste production compared to stoichiometric zinc consumption. This aligns with green chemistry principles for industrial scalability.
3Productivity
If palladium catalyst supported on carrier is used for gas phase reduction of HFC-1214ya to produce HFO-1234yf, then the reaction can proceed, but the yield remains unsatisfactory and requires further improvement
Solution Approach 1:
The patent employs a composite catalyst system combining chromium oxyfluoride with other materials to achieve satisfactory yield. The composite structure enhances catalytic activity and selectivity compared to simple palladium catalysts.
4Productivity
If other reported processes (amine reaction, thermal decomposition, Lewis acid catalysis) are used to prepare HFO-1234yf, then the reaction can proceed, but they are not effective for industrial purposes due to difficult starting materials, severe conditions, expensive reagents, or low yield
Solution Approach 1:
The patent optimizes reaction parameters including temperature, pressure, molar ratios, and catalyst composition to achieve a balance between effectiveness and feasibility. The modified conditions make the process suitable for industrial application while maintaining high yield.
Solution Approach 2:
The patent replaces expensive reagents (amines, Lewis acids like SbF5) with more economical chromium-based catalysts, making the process economically viable for industrial production while maintaining effectiveness.
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 achieves high yield and selectivity of HFO-1234yf, maintaining catalytic activity over an extended period while reducing catalyst degradation, making it economically viable for industrial production.
Implementation Method 1
contacting a fluorine-containing propane represented by the formula CF2XCFYCH2Z with at least one catalyst selected from the group consisting of chromium oxides, fluorinated chromium oxides, and iron fluorides in a gas phase
Data Source
AI summary
The present invention provides a process for producing 2,3,3,3-tetrafluoropropene represented by the formula CF3CF=CH2, comprising contacting a fluorine-containing propane represented by the formula CF2XCFYCH2Z, wherein X is Cl, Br, or I; one of Y and Z is H, and the other is F, Cl, Br, or I, with at least one catalyst selected from the group consisting of chromium oxides, fluorinated chromium oxides, and iron fluorides in a gas phase. According to the process of the invention, 2,3,3,3-tetrafluoropropene can be easily produced under economically advantageous conditions.