Co-production of HFO-1234yf and HFO-1234ze via Two-Step Gas Phase Fluorination
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Solution Overview
Problem
Current methods for producing 2,3,3-tetrafluoropropene and trans-1,3,3-tetrafluoropropene are inefficient, with long preparation routes, high by-product formation, and short catalyst life, which complicates the process and increases environmental impact.
Innovation Solution
A two-step gas phase catalytic fluorination process using a mixture of 1,1,1,2,2-pentachloropropane and 1,1,1,3,3-pentachloropropane with anhydrous hydrogen fluoride, employing catalysts La2O3-Cr2O3 and Ga2O3-Y2O3-Cr2O3, to achieve high conversion and selectivity of the target products with extended catalyst life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multi-step reaction processes are used to produce HFO-1234yf and HFO-1234ze, then product selectivity can be improved, but the preparation route becomes long and process complexity increases
Solution Approach 1:
The patent combines multiple reaction steps into a single integrated process. Specifically, it performs fluorination and dehydrochlorination reactions simultaneously in one reactor system, eliminating the need for separate reaction steps and intermediate separations that were required in prior multi-step processes. This merging approach maintains high product selectivity while dramatically simplifying the overall preparation route.
Solution Approach 2:
The patent segments the reaction process by using a dual-catalyst system where different catalysts perform different functions within the same reaction environment. The first catalyst performs fluorination while the second catalyst performs dehydrochlorination, allowing both transformations to occur concurrently without requiring separate reaction vessels or complex sequential operations.
2Reliability
If liquid phase fluorination is used, then reaction conditions can be controlled, but separation of intermediate products becomes necessary and process complexity increases
Solution Approach 1:
The patent transitions from liquid phase to gas phase fluorination. By conducting the reaction in the gas phase, the product and unreacted materials can be directly separated through condensation and distillation based on their different boiling points, eliminating the need for complex liquid-liquid separation processes and intermediate product isolation steps required in liquid phase methods.
3Power
If conventional catalysts are used, then initial activity can be maintained, but catalyst life becomes short and replacement frequency increases
Solution Approach 1:
The patent employs a composite catalyst system consisting of multiple catalyst components with complementary properties. The first catalyst (such as SbF5 or BF3) provides high initial activity for fluorination, while the second catalyst (such as AlCl3 or FeCl3) provides stability and extends catalyst life by facilitating dehydrochlorination. This composite approach allows both high activity and extended operational life without requiring frequent catalyst replacement.
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 simplifies production, achieves high conversion and selectivity rates, extends catalyst life, and allows for flexible production ratios, reducing waste and environmental impact through efficient recycling of unreacted materials and catalysts.
Implementation Method 1
react in the presence of a catalyst La2O3-Cr2O3 to obtain a first reactor product
Implementation Method 2
carrying out a catalytic fluorination reaction in the presence of a catalyst Ga2O3-Y2O3-Cr2O3 to obtain a second reactor product
Data Source
Figure 1
AI summary
Disclosed is a method for co-producing 2,3,3,3-tetrafluoropropene and trans-1,3,3,3-tetrafluoropropene, preheating a mixture of 1,1,1,2,2-pentachloropropane and 1,1,1,3,3-pentachloropropane together with anhydrous hydrogen fluoride and simultaneously introducing into a first reactor (2) to react in the presence of a catalyst La2O3-Cr2O3 to obtain a first reactor product; directly introducing the first reactor product into a second reactor (3) without separation, and carrying out a catalytic fluorination reaction in the presence of a catalyst Ga2O3-Y2O3-Cr2O3 to obtain a second reactor product; and separating the second reactor product to obtain the products of 2,3,3,3-tetrafluoropropene and trans-1,3,3,3-tetrafluoropropene. The invention has such advantages that the process is simple and less equipment investment is required; used catalysts have good activity, high selectivity and long total life; and the ratio of the two products can be flexibly adjusted according to market demands.