HCFO-1233xf Hydrofluorination Catalyst Management
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Solution Overview
Problem
Current methods for producing 2,3,3,3-tetrafluoropropene (HFO-1234yf) face challenges such as high costs and yield losses due to the formation of 1,1,1,2,2-pentafluoropropane (HFC-245cb) in the production of 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) from 2-chloro-3,3,3-trifluoropropene and hydrogen fluoride, which deactivates catalysts and requires additional separation steps.
Innovation Solution
A process involving the reaction of 2-chloro-3,3,3-trifluoropropene with hydrogen fluoride in a liquid phase reaction vessel using a liquid phase hydrofluorination catalyst, with periodic or continuous addition of fresh catalyst in small increments to maintain HCFC-244bb conversion above 80% and minimize HFC-245cb formation below 20%, effectively controlling the selectivity and extending the reaction duration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a liquid phase hydrofluorination catalyst is used to produce HCFC-244bb from HCFO-1233xf and HF, then the conversion of HCFO-1233xf can be maintained above 80%, but the formation of HFC-245cb increases to over 20% causing yield loss and catalyst deactivation
Solution Approach 1:
The patent applies periodic action by periodically adding small increments of fresh hydrofluorination catalyst to the reaction system. This periodic catalyst addition maintains high HCFO-1233xf conversion (above 80%) while controlling HFC-245cb formation (below 20%) by preventing catalyst deactivation and maintaining optimal reaction conditions throughout the extended reaction period
Solution Approach 2:
The patent employs parameter changes by adjusting the catalyst amount dynamically during the reaction process. By changing the catalyst concentration through periodic additions, the reaction selectivity is optimized to favor HCFC-244bb production over HFC-245cb formation, thereby improving yield while maintaining high conversion
2Productivity
If the reaction is extended to maintain high conversion, then productivity improves, but catalyst deactivation occurs leading to increased HFC-245cb formation
Solution Approach 1:
The patent applies the discarding and recovering principle by periodically removing deactivated catalyst portions and replacing them with fresh catalyst. This allows the reaction to proceed for extended durations maintaining high productivity while recovering and replacing only the deactivated catalyst portions, thus maintaining overall catalyst performance and reliability
Solution Approach 2:
The patent uses periodic catalyst addition to counteract catalyst deactivation during extended reaction periods. This periodic replenishment of active catalyst maintains reliable catalytic function throughout the extended reaction duration, enabling sustained high productivity without significant HFC-245cb formation
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 approach enhances the conversion of 2-chloro-3,3,3-trifluoropropene to 2-chloro-1,1,1,2-tetrafluoropropane while reducing the formation of 1,1,1,2,2-pentafluoropropane, thereby improving yield and process efficiency, allowing for prolonged operation with maintained catalyst performance.
Implementation Method 1
reacting 2-chloro-3,3,3-trifluoropropene with hydrogen fluoride, in a liquid phase reaction vessel in the presence of a liquid phase hydrofluorination catalyst
Data Source
Figure 1
AI summary
The present process relates to a method for minimizing the formation of 1,1,1,2,2-pentafluoropropane in a liquid phase reaction of 2-chloro-3,3,3-trifluoropropene and HF in the presence of a hydrofluorination catalyst comprising: (a) reacting HF with sufficient amount of 2-chloro-3,3,3-trifluoropropene in the presence of a hydrofluorination catalyst under conditions effective to form 2-chloro-1,1,1,2-tetrafluoropropane, the hydrofluorination catalyst being present in sufficient amounts to catalyze said reaction and the 2-chloro-1,1,1,2-tetrafluoropropane being formed with both a conversion of greater than 80% and a 1,1,1,2,2-pentafluoropropane selectivity lower than 20%; and (b) maintaining the 2-chloro-1, 1, 1, 2-tetrafluoropropane being formed with both a conversion of about 80% or more and a 1,1,1,2,2-pentafluoropropane selectivity of about 20% or less by adding said hydrofluorination catalyst to the reactor in small increments.