Zirconium Modified Silica Catalyst for Methacrylic Acid Production
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Solution Overview
Problem
Current catalysts for producing ethylenically unsaturated carboxylic acids or esters, such as acrylic acids or esters, suffer from low selectivity and rapid catalyst surface sintering during the condensation of carboxylic acids or esters with formaldehyde, leading to reduced reaction efficiency and catalyst lifespan.
Innovation Solution
A modified silica catalyst support is developed, featuring zirconium and/or hafnium oxide moieties derived from monomeric or dimeric modifier metal sources, which improves catalytic metal binding and selectivity, and retards catalyst surface sintering by maintaining a high proportion of monomeric or dimeric modifier metal atoms on the silica surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional catalysts are used for the condensation of carboxylic acids or esters with formaldehyde, then the reaction can proceed, but the catalyst exhibits low selectivity and rapid surface sintering
Solution Approach 1:
The patent modifies the physical and chemical parameters of the silica support by incorporating specific amounts of metal oxides (0.1-10 wt% Al2O3, TiO2, ZnO, or ZrO2) to change the surface properties, acidity, and structural stability of the catalyst, thereby improving both selectivity and resistance to sintering
Solution Approach 2:
The patent creates composite catalyst materials by combining silica support with metal oxide modifiers to form a composite structure that leverages the properties of both materials: silica provides the base structure and porosity, while metal oxides enhance selectivity and prevent sintering through their electronic and structural effects
2Productivity
If the catalyst surface area is increased to improve reaction efficiency, then productivity increases, but the catalyst surface sintering accelerates reducing lifespan
Solution Approach 1:
The patent applies metal oxide modifiers beforehand to the silica support to create a protective layer that cushions against sintering effects during high-temperature reactions, allowing the catalyst to maintain high surface area and activity for extended periods without rapid degradation
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 modified silica catalysts exhibit enhanced selectivity and reduced sintering, resulting in improved efficiency and extended catalyst lifespan for the production of ethylenically unsaturated carboxylic acids or esters, specifically methacrylic acid and methyl methacrylate.
Implementation Method 1
a modified silica catalyst support is developed, featuring zirconium and/or hafnium oxide moieties derived from monomeric or dimeric modifier metal sources, which improves catalytic metal binding
Implementation Method 2
retards catalyst surface sintering by maintaining a high proportion of monomeric or dimeric modifier metal atoms on the silica surface
Implementation Method 3
a process for the production of ethylenically unsaturated carboxylic acids or esters, particularly α, β unsaturated carboxylic acids or esters, more particularly acrylic acids or esters such as (alk)acrylic acids or alkyl (alk)acrylates particularly (meth)acrylic acids or alkyl (meth)acrylates such as methacrylic acid (MA) and methyl methacrylate (MMA) by the condensation of carboxylic acid or esters with formaldehyde or a source thereof such as dimethoxymethane in the presence of such catalysts
Data Source
AI summary
A catalyst has a modified silica support and comprises a modifier metal, zirconium and/or hafnium, and a catalytic metal on the modified support. The catalyst has at least a proportion, typically, at least 25%, of modifier metal present in moieties having a total of up to 2 modifier metal atoms. The moieties may be derived from a monomeric and/or dimeric cation source.A method of production:provides a silica support with isolated silanol groups with optional treatment to provide isolated silanol groups (—SiOH) at a level of <2.5 groups per nm2;contacting the optionally treated silica support with a monomeric zirconium or hafnium modifier metal compound to effect adsorption onto the support; andoptionally calcining the modified support for a time and temperature sufficient to convert the monomeric zirconium or hafnium compound adsorbed on the surface to an oxide or hydroxide of zirconium or hafnium in preparation for catalyst impregnation.