Catalyst-Free Gas-Phase Fluorination of Chloropropane
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Solution Overview
Problem
Current processes for preparing 2-chloro-3,3,3-trifluoropropene (HCFC-1233xf) suffer from low yield, high catalyst costs, and unsatisfactory selectivity, making them unsuitable for industrial-scale production.
Innovation Solution
A process involving a reaction between a chloropropane or chloropropene compound and hydrogen fluoride in the gas phase without a catalyst at elevated temperatures, using specific chlorine-containing compounds as starting materials, to achieve high yield and selectivity in a single step.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a catalyst is used for fluorination of 1,1,2,3-tetrachloropropene, then the reaction rate increases, but the cost increases and selectivity decreases
Solution Approach 1:
The patent removes the catalyst from the reaction system entirely. Instead of using a chromium-based catalyst that increases cost and reduces selectivity, the invention uses a catalyst-free approach with specific chlorine-containing compounds as starting materials, achieving high yield and selectivity without catalyst costs
Solution Approach 2:
The patent changes the reaction parameters by using specific chlorine-containing compounds (formulae 1, 2, or 3) as starting materials instead of conventional 1,1,2,3-tetrachloropropene. This parameter change in the starting material structure enables the reaction to proceed without catalyst while maintaining high reaction efficiency and selectivity
2Speed
If a catalyst is used for fluorination, then the reaction rate increases, but the yield decreases due to multiple products
Solution Approach 1:
The patent eliminates the catalyst that causes unwanted side reactions. By using a catalyst-free system with specific starting materials, the reaction achieves high selectivity for the target product HCFC-1233xf, avoiding the formation of multiple by-products that occur with catalytic processes
Solution Approach 2:
The invention changes the chemical parameters by selecting specific chlorine-containing compounds with particular structures (formulae 1, 2, or 3) as starting materials. This structural parameter change ensures that the fluorination reaction proceeds selectively to form only the desired HCFC-1233xf product, achieving both high yield and high selectivity simultaneously
3Reliability
If conventional fluorination process is used, then the process is established, but the reaction time is long and conditions are severe
Solution Approach 1:
The patent optimizes reaction parameters by using specific starting materials (formulae 1, 2, or 3) that react rapidly with hydrogen fluoride. This parameter change in the starting material structure enables the reaction to proceed under mild conditions with short reaction time, while maintaining process stability through controlled reaction conditions
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 method enables efficient and economical production of HCFC-1233xf with high yield and selectivity, suitable for industrial-scale production, eliminating the drawbacks of previous processes.
Implementation Method 1
subjecting, in the absence of a catalyst, at least one chlorine-containing compound selected from the group consisting of chloropropane represented by formula (1), chloropropene represented by formula (2), and chloropropene represented by formula (3), to a reaction with hydrogen fluoride
Data Source
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AI summary
The present invention provides a process for preparing 2-chloro-3,3,3-trifluoropropene including subjecting, in the absence of a catalyst, at least one chlorine-containing compound selected from the group consisting of chloropropane represented by formula (1): CClX2CHClCH2Cl, wherein each X is the same or different and each represents Cl or F, chloropropene represented by formula (2): CClY2CCl=CH2, wherein each Y is the same or different and each represents Cl or F, and chloropropene represented by formula (3): CZ2=CClCH2Cl, wherein each Z is the same or different and each represents Cl or F, to a reaction with hydrogen fluoride under heating in a gas phase. According to the present invention, 2-chloro-3,3,3-trifluoropropene (HCFC-1233xf) can be effectively prepared by an easy and economically advantageous process that is suitable for industrial scale production.