Eggshell Catalyst for Aromatic Hydrogenation
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Solution Overview
Problem
Existing catalysts for hydrogenating organic compounds, particularly aromatic compounds, face challenges in achieving high conversion rates and selectivity for desired target products while maintaining catalyst stability over long periods.
Innovation Solution
An eggshell catalyst comprising ruthenium, rhodium, palladium, or platinum applied to a silicon dioxide support with specific pore volume, BET surface area, and pore diameter, where the active metal is predominantly present in the outer shell, enhancing activity and selectivity in hydrogenation processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional supported catalysts are used for hydrogenation, then the catalyst can perform the hydrogenation function, but the conversion rate and selectivity for desired target products are insufficient
Solution Approach 1:
The patent applies local quality by creating an eggshell catalyst where the active metal is concentrated in the outer shell region (0-50 μm from surface) rather than uniformly distributed throughout the support. This localized distribution optimizes the catalyst structure to simultaneously achieve high conversion rates through increased active sites at the surface and high selectivity by controlling reaction pathways in the outer shell region, resolving the contradiction between productivity and reliability.
2Duration of action of stationary object
If conventional supported catalysts are used for hydrogenation, then the catalyst can perform the hydrogenation function, but the stability and activity retention over long periods are insufficient
Solution Approach 1:
The eggshell catalyst structure with active metal concentrated in the outer shell (0-50 μm) protects the bulk support material from degradation while maintaining catalytic activity. The localized active metal distribution in the outer shell region enhances stability by preventing bulk support degradation and maintains activity retention through optimized surface exposure, resolving the contradiction between duration of action and reliability.
3Productivity
If the active metal is uniformly distributed throughout the support, then the catalyst structure is simple, but the hydrogenation activity and selectivity are reduced
Solution Approach 1:
The patent implements local quality by concentrating the active metal in the outer shell region (0-50 μm from surface) rather than uniform distribution. This creates a functional gradient structure that enhances hydrogenation activity through optimized surface exposure and maintains selectivity through controlled reaction pathways, while the overall eggshell architecture provides a systematic framework that manages the increased structural complexity.
Solution Approach 2:
The eggshell catalyst represents a composite material system combining the support material (e.g., silica, alumina) with the active metal component in a specific spatial arrangement. The outer shell contains the active metal species while the inner core provides structural support, creating a composite structure that optimizes both activity and selectivity while managing complexity through hierarchical organization.
4Area of stationary object
If the pore size of the support material is small, then the surface area is high, but the mass transfer and accessibility of reactants are limited
Solution Approach 1:
The patent utilizes porous support materials with optimized pore size distribution and pore volume (0.3-1.2 ml/g) to achieve high BET surface area while maintaining efficient mass transfer. The porous structure provides high surface area for active metal dispersion and simultaneously allows adequate reactant accessibility through controlled pore architecture, resolving the contradiction between surface area and mass transfer efficiency.
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 catalyst achieves high conversion and selectivity for hydrogenation of organic compounds, including carbocyclic aromatic groups, with prolonged stability and activity retention, even after extended hydrogenation periods.
Implementation Method 1
The processes described in the prior art for hydrogenation of organic compounds are performed in the presence of appropriate catalysts, especially supported catalysts, i.e. an active metal is applied to a support material
Implementation Method 2
the BET surface area is 280 to 500 m2/g
Data Source
AI summary
The present invention relates to an eggshell catalyst comprising an active metal selected from the group consisting of ruthenium, rhodium, palladium, platinum and mixtures thereof, applied to a support material comprising silicon dioxide, wherein the pore volume of the support material is 0.6 to 1.0 ml/g, determined by Hg porosimetry, the BET surface area is 280 to 500 m2/g, and at least 90% of the pores present have a diameter of 6 to 12 nm, to a process for preparing this eggshell catalyst, to a process for hydrogenating an organic compound which comprises at least one hydrogenatable group using the eggshell catalyst, and to the use of the eggshell catalyst for hydrogenating an organic compound.