Hexavalent Chromium Catalyst for Ambient Hydrocarbon Conversion
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Solution Overview
Problem
Current methods for converting hydrocarbons into alcohols and carbonyls often require harsh conditions or halogens, and existing supported chromium catalysts are limited by high calcination temperatures and chromium loading constraints, which restrict efficiency and yield.
Innovation Solution
The process involves irradiating a hydrocarbon reactant with a supported chromium catalyst in the UV-visible spectrum to reduce chromium, followed by hydrolysis, which allows for the conversion of hydrocarbons into alcohols and carbonyls at ambient temperature, using lower heat treatment temperatures and higher chromium loadings, thereby overcoming traditional catalyst limitations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional supported chromium catalysts are used for converting hydrocarbons to alcohols, then the reaction can proceed, but high calcination temperatures and low chromium loadings are required, which reduce efficiency and yield
Solution Approach 1:
The patent changes the oxidation state parameter of chromium from conventional +3 to +6, which fundamentally alters the catalyst's properties. This parameter change enables the catalyst to function at lower calcination temperatures while achieving higher chromium loadings (up to 10 times higher than conventional catalysts), thereby resolving the contradiction between productivity and temperature requirements
Solution Approach 2:
The patent creates a composite catalyst system by combining hexavalent chromium species with specific support materials (such as silica, alumina, or mixed oxides). This composite structure stabilizes the hexavalent chromium and enables high loadings without requiring high calcination temperatures, thus improving productivity while reducing the temperature constraint
2Productivity
If conventional chromium catalysts are used, then the catalyst structure is stable, but chromium loadings must be kept low, which limits reaction efficiency
Solution Approach 1:
By changing the chromium oxidation state to +6, the patent enables much higher chromium loadings (up to 10 times higher than conventional catalysts) without compromising structural stability. The hexavalent chromium forms stable surface complexes with the support material, allowing high loadings while maintaining catalyst integrity and improving reaction efficiency
Solution Approach 2:
The hexavalent chromium catalyst exhibits multiple functions: it acts as both the active catalytic species and a stable surface complex with the support. This multi-functionality allows high chromium loadings to be maintained without sacrificing stability, thereby improving productivity while increasing the quantity of active chromium species
3Reliability
If traditional alcohol synthesis methods are used, then alcohols can be produced, but harsh reaction conditions or halogens are required, which reduce selectivity and increase environmental impact
Solution Approach 1:
The patent changes the reaction condition parameters by using hexavalent chromium catalysts that enable alcohol synthesis under mild conditions without requiring halogens or harsh reagents. This parameter change improves selectivity while eliminating harmful factors associated with conventional methods
Solution Approach 2:
The patent converts the traditionally problematic hexavalent chromium, which is difficult to stabilize, into a beneficial catalytic species by using it in a photocatalytic system. The light irradiation provides a gentle activation mechanism that avoids harsh conditions while maintaining high selectivity, thus converting a potential harm into a benefit
4Productivity
If high chromium loadings are used to improve efficiency, then more active sites are available, but conventional catalysts require high calcination temperatures that may damage the support structure
Solution Approach 1:
By changing the chromium oxidation state to +6, the patent enables high chromium loadings to be achieved at lower calcination temperatures. The hexavalent chromium forms stable surface complexes that prevent sintering and support degradation, thus maintaining support structure integrity while improving catalyst activity through higher loadings
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 efficiently converts hydrocarbons into alcohols and carbonyls with higher yields and selectivity, achieving conversions up to 100% at ambient temperature without the need for harsh conditions, using lower heat treatment temperatures and allowing for higher chromium loadings than conventional methods.
Implementation Method 1
irradiating the hydrocarbon reactant and a supported chromium catalyst comprising chromium in a hexavalent oxidation state with a light beam at a wavelength in the UV-visible spectrum
Implementation Method 2
hydrolyzing the reduced chromium catalyst to form a reaction product comprising the alcohol compound and/or the carbonyl compound
Data Source
AI summary
Processes for converting a hydrocarbon reactant into an alcohol compound and/or a carbonyl compound are disclosed, and these processes include the steps of irradiating the hydrocarbon reactant and a supported chromium catalyst comprising chromium in a hexavalent oxidation state with a light beam at a wavelength in the UV- visible spectrum to reduce at least a portion of the supported chromium catalyst to form a reduced chromium catalyst, and hydrolyzing the reduced chromium catalyst to form a reaction product comprising the alcohol compound and/or the carbonyl compound. In addition, these processes can further comprise a step of calcining all or a portion of the reduced chromium catalyst to regenerate the supported chromium catalyst.