Metal Oxyfluoride Supported Catalyst for Fluoroolefin Hydrogenation
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Solution Overview
Problem
Existing catalysts for hydrogenating fluoroolefins are prone to deactivation due to hydrogenolytic cleavage of carbon-fluorine bonds, leading to the generation of HF, which attacks common support materials like alumina and silica, and are not regenerable once deactivated.
Innovation Solution
Supporting metal catalysts on metal oxyfluorides or metal fluorides, such as CrF3, TiF4, and ZrF4, which are resistant to HF and allow for regenerability, with a method involving the preparation of a slurry, calcination, and reduction to form a supported catalyst with a specific metal loading.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If Pd/Al2O3 or Pd/silica catalysts are used for hydrogenation of fluoroolefins, then hydrogenation activity is improved, but catalyst stability deteriorates due to HF attack causing structure change and deactivation
Solution Approach 1:
The patent introduces a protective coating layer comprising metal fluoride or metal oxyfluoride as an intermediary between the Pd catalyst and the HF environment. This coating acts as a barrier that prevents direct contact between HF and the catalyst support, thereby protecting the catalyst structure while maintaining hydrogenation activity. The coating is applied by contacting the catalyst with aqueous KF solution followed by drying and calcination to form a protective surface layer.
Solution Approach 2:
The patent creates a composite catalyst structure by combining Pd metal particles supported on alumina or silica with a surface coating of metal fluoride or metal oxyfluoride. This composite structure integrates the high hydrogenation activity of Pd with the HF resistance of metal fluorides, achieving both productivity and reliability requirements.
2Reliability
If carbon supported metal catalysts are used to resist HF attack, then catalyst stability is improved, but regenerability deteriorates as they cannot be regenerated once deactivated
Solution Approach 1:
The patent changes the chemical composition parameters of the catalyst surface by introducing metal fluoride or metal oxyfluoride coatings with specific fluorine content (0.1-10 wt%). This parameter adjustment provides both HF resistance and maintains the ability to regenerate the catalyst through standard calcination and reduction procedures, unlike carbon-supported catalysts.
3Ease of manufacture
If metal oxides are used as catalyst supports, then ease of manufacture is improved, but catalyst stability deteriorates due to unstable activity in fluoroolefin hydrogenation
Solution Approach 1:
The patent applies a metal fluoride or metal oxyfluoride coating as an intermediary layer on conventional metal oxide supports like alumina and silica. This coating mediates the interaction between the catalyst and the reactive fluoroolefin/HF environment, providing stable activity while allowing the use of easily manufactured metal oxide supports.
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 catalysts exhibit stable activity and can be regenerated, maintaining high conversion and selectivity in hydrogenation reactions, as demonstrated by the efficient production of hydrofluorocarbons with improved resistance to HF attack.
Implementation Method 1
Catalytic hydrogenation of fluoroolefins is frequently used in producing hydro fluorocarbons as useful products and/or intermediates. Various metals, such as Pd, supported on a substrate have long been recognized as highly effective hydrogenation catalysts.
Implementation Method 2
The method involving the preparation of a slurry, calcination, and reduction to form a supported catalyst with a specific metal loading.
Implementation Method 3
contacting said support catalyst with a gaseous composition comprising H2 to activate said supported catalyst
Implementation Method 4
A method for hydrogenation of fluoroolefins
Data Source
AI summary
A support of metal oxyfluoride or metal halide for a metal-based hydrogenation catalyst useful in hydrogenating fluoroolefins is provided.