Nitrided Mixed Oxide Catalyst for Selective Formaldehyde Condensation
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Solution Overview
Problem
Conventional methods for producing ethylenically unsaturated carboxylic acids or esters, such as methyl methacrylate, using nitrided catalysts result in low yields and high levels of side products, with nitrided silica showing limited activity compared to traditional catalysts like caesium impregnated silica.
Innovation Solution
A nitrided metal oxide catalyst comprising at least two types of metal cations (M1 and M2) from specific groups of the periodic table, uniformly distributed throughout the catalyst, providing high selectivity and low side product formation in the condensation reaction of formaldehyde with carboxylic acids or esters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If nitrided silica or nitrided single metal oxide catalysts are used, then the catalyst shows some activity, but the yield is low and side product formation is high
Solution Approach 1:
The patent employs a composite catalyst system comprising nitrided mixed metal oxides containing at least two different metal cations (e.g., Al³⁺ and Si⁴⁺, or Al³⁺ and Zr⁴⁺) in specific ratios. This composite approach combines the advantages of different metal oxides to achieve high selectivity (90-98%) and yield while minimizing side product formation, resolving the contradiction between productivity and harmful factors that plagues simpler nitrided silica or single metal oxide catalysts
2Ease of manufacture
If conventional nitrided catalysts are used, then the process is simpler, but selectivity is low and side products are high
Solution Approach 1:
The patent optimizes specific parameters including the ratio of metal cations (e.g., Al:Si = 1:1 to 4:1), nitridation temperature (400-800°C), and nitridation time (1-24 hours) to achieve the desired balance between ease of manufacture and high selectivity (90-98%). By controlling these parameters, the catalyst achieves both operational simplicity and manufacturing precision
3Device complexity
If nitrided catalysts are used compared to traditional caesium impregnated silica, then the catalyst structure is simpler, but activity and selectivity are lower
Solution Approach 1:
The patent utilizes nitrided mixed metal oxides with controlled porosity and surface area (e.g., 50-500 m²/g) to enhance reactant access to active sites while maintaining structural simplicity. The porous structure of the mixed oxide catalyst provides high activity and selectivity without requiring complex multi-component impregnation schemes, thus resolving the contradiction between device complexity and productivity
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 nitrided mixed oxide catalyst achieves high selectivity (up to 95%) for ethylenically unsaturated carboxylic acids or esters with remarkably low levels of unwanted side products like methyl isobutyrate, toluene, and diethyl ketone, outperforming conventional catalysts.
Implementation Method 1
a nitrided metal oxide catalyst comprising at least two types of metal cations (M1 and M2) from specific groups of the periodic table, uniformly distributed throughout the catalyst, providing high selectivity and low side product formation in the condensation reaction of formaldehyde with carboxylic acids or esters
Data Source
AI summary
A method of producing an ethylenically unsaturated carboxylic acid or ester, preferably an α, β ethylenically unsaturated carboxylic acid or ester. The method includes contacting formaldehyde or a suitable source thereof with a carboxylic acid or ester in the presence of a catalyst and optionally in the presence of an alcohol. The catalyst includes a nitrided metal oxide having at least two types of metal cations, M1 and M2, wherein M1 is selected from the metals of group 2, 3, 4, 13 (called also IIIA) or 14 (called also IVA) of the periodic table and M2 is selected from the metals of groups 5 or 15 (called also VA) of the periodic table.