Fluorinated Olefin Production with Selective Catalytic Conversion
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Solution Overview
Problem
Existing methods for producing hydrofluorocarbons, such as hydrofluoroalkenes, face challenges in safety, high costs, and low yields, particularly due to the use of hydrogen gas and inefficient conversion processes.
Innovation Solution
A method involving the conversion of CH2=CClCF3 to CF3CF2CH3 and subsequently to CF3CF=CH2 through fluorination and dehydrohalogenation reactions, using catalysts like Cr2O3 and FeCl3/C, with controlled reaction conditions to achieve high selectivity and yield.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If hydrogen gas is used to convert fluorinated alcohols to fluorine containing olefins, then high yield is achieved, but safety risks and production costs increase due to handling hydrogen gas at high temperature
Solution Approach 1:
The patent replaces expensive and dangerous hydrogen gas with a more economical and safer alternative reagent system. The invention uses sulfur tetrafluoride (SF4) or gaseous inorganic fluorinating agents instead of hydrogen gas, eliminating the need for costly hydrogen production facilities and reducing safety risks associated with high-temperature hydrogen handling.
Solution Approach 2:
The patent changes the reaction parameters and reagents used in the fluorination process. Instead of using hydrogen gas at high temperature, the invention employs sulfur tetrafluoride or other inorganic fluorinating agents under different reaction conditions, thereby achieving high yield without the safety and cost issues of hydrogen handling.
2Ease of manufacture
If pyrolysis of methyl chloride and tetrafluoroethylene is used to make fluorine containing olefins, then the process is simple, but yield is low and large amounts of unwanted byproducts are formed
Solution Approach 1:
The patent introduces sulfur tetrafluoride (SF4) or other inorganic fluorinating agents as intermediaries in the fluorination process. These intermediaries enable selective fluorination of the substrate to produce the desired fluorine-containing olefin with high yield, avoiding the formation of unwanted byproducts that occur in direct pyrolysis methods.
Solution Approach 2:
The patent changes the reaction conditions and reagents from direct pyrolysis to a controlled fluorination process using sulfur tetrafluoride or other inorganic fluorinating agents. This parameter change maintains process simplicity while dramatically improving yield and reducing byproduct formation.
3Quantity of substance
If conventional fluorination methods are used, then fluorinated compounds are produced, but conversion efficiency and selectivity are insufficient
Solution Approach 1:
The patent uses sulfur tetrafluoride (SF4) or gaseous inorganic fluorinating agents as intermediaries that provide controlled and selective fluorination. These intermediaries react with the substrate to produce the desired fluorinated product with high conversion efficiency and selectivity, avoiding the formation of unwanted isomers or byproducts.
Solution Approach 2:
The patent optimizes reaction parameters including temperature, pressure, and reagent ratios to achieve high conversion efficiency and selectivity. By controlling these parameters and using specific inorganic fluorinating agents, the process achieves superior conversion rates and product selectivity compared to conventional methods.
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 method achieves high conversion rates and selectivity for hydrofluoropropenes, addressing safety and cost concerns by optimizing reaction conditions and catalyst use.
Implementation Method 1
using catalysts like Cr2O3 and FeCl3/C, with controlled reaction conditions to achieve high selectivity and yield
Implementation Method 2
subsequently converting the CF3CF2CH3 (245cb) to a compound of Formula (II) (CF3CF=CH2 (1234yf))
Data Source
AI summary
Disclosed are processes for the production of fluorinated olefins, preferably adapted to commercialization of CF3CF=CH2 (1234yf). Three steps may be used in preferred embodiments in which a feedstock such as CCl2=CClCH2Cl (which may be purchased or synthesized from 1,2,3-trichloropropane) is fluorinated (preferably with HF in gas-phase in the presence of a catalyst) to synthesize a compound such as CFaCCI=CH2, preferably in a 80-96% selectivity. The CF3CCl=CH2 is preferably converted to CF3CFClCH3 (244-isomer) using a SbCl5 as the catalyst which is then transformed selectively to 1234yf, preferably in a gas-phase catalytic reaction using activated carbon as the catalyst. For the first step, a mixture of Cr2O3 and FeCl3/C is preferably used as the catalyst to achieve high selectivity to CF3CCl=CH2 (96%). In the second step, SbCls/C is preferably used as the selective catalyst for transforming 1233xf to 244-isomer, CF3CFClCH3. The intermediates are preferably isolated and purified by distillation and used in the next step without further purification, preferably to a purity level of greater than about 95%.