Silica Carrier Composition for High-Surface-Area Catalyst Support
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Solution Overview
Problem
Existing silica carriers for catalysts face issues with poor versatility, require special apparatus, have insufficient BET specific surface area, and may interact with catalyst components, reducing their activity.
Innovation Solution
A method involving kneading fumed silica, silica gel, and colloidal silica, followed by molding and calcining, to create a silica carrier with a high BET specific surface area and pore volume, enhancing catalytic activity and selectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a silica carrier is treated with a hydrosilane compound at high temperature, then the activation treatment is eliminated, but the method requires special apparatus and has poor versatility
Solution Approach 1:
The invention changes the chemical composition parameters of the silica carrier by incorporating specific metal oxides (magnesium, calcium, aluminum) in controlled amounts during the sol-gel process. This compositional modification eliminates the need for subsequent activation treatments while maintaining broad applicability across different catalyst systems, resolving the contradiction between manufacturing simplicity and method versatility
2Volume of stationary object
If silicic acid solution is added during production to increase pore volume, then pore volume is improved, but BET specific surface area becomes insufficient
Solution Approach 1:
The invention employs a dual-pore structure design where mesopores (2-50 nm) and macropores (50 nm to 1 μm) coexist in the silica carrier. This hierarchical porous architecture, achieved through controlled sol-gel processing with metal oxide additives, simultaneously provides sufficient pore volume for catalyst support and maintains high BET specific surface area for effective catalytic activity, resolving the contradiction between pore volume and surface area
3Temperature
If silica containing magnesium or talc structure is used to achieve heat resistance and large surface area, then heat resistance and surface area are improved, but catalyst component activity is reduced due to interaction
Solution Approach 1:
The invention precisely controls the concentration parameters of metal oxides, limiting magnesium oxide to 0.1-5 mass% and aluminum oxide to 0.1-5 mass% in the silica carrier. This quantitative control prevents harmful interactions with catalyst components while maintaining the desired heat resistance and surface area properties, thereby resolving the contradiction between thermal stability and catalytic activity
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 resulting silica carrier supports catalytic components effectively, leading to high-performance catalysts for reactions like ethyl acetate production from ethylene and acetic acid, with improved activity and selectivity.
Implementation Method 1
a silane compound or a sulfate ester compound is added to a silicic acid solution to adjust the pH of the silica gel slurry, thereby causing a sol-gel reaction
Implementation Method 2
drying said gel to remove the solvent from the solvent-rich phase by evaporation, thereby forming the macropores
Implementation Method 3
removing said template component from the dried gel by thermal decomposition or extraction, thereby forming the mesopores within the skeleton phase
Data Source
Figure 1~2
Figure 3
AI summary
To provide a silica carrier exhibiting high activity and selectivity when a catalytic component is supported thereon. The method for producing the silica carrier includes kneading fumed silica obtained by a combustion method, silica gel obtained by a gel method, and colloidal silica obtained by a sol-gel method or a water glass method, molding the resulting kneaded product, and calcining the resulting molded body. The silica carrier has, in the measurement of pore size distribution, mesopores with a pore size of 2 to 50 nm and macropores with a pore size of more than 50 nm and 1,000 nm or less.