Polyoxometalate Catalyst Ligand Removal
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Solution Overview
Problem
Existing catalysts for producing unsaturated carboxylic acids from unsaturated aldehydes face challenges in controlling activity and selectivity, reproducibility, and maintaining high yield and long lifespan, particularly due to issues with catalyst poisons and structural changes during high-temperature drying.
Innovation Solution
A polyoxometalate catalyst with specific metal oxide compositions (Mo12V5.0W2.0Nb0.1Sr1.0Co1.0, Mo12V3.0W3.0Nb0.1Sr1.0Co0.5Fe0.5, and Mo12V1.5W2.0Nb0.1Ni4.0) is developed, supported on an inactive carrier, with controlled ligand sublimation and firing conditions to enhance activity and selectivity, and used in a partial vapor-phase oxidation process in a shell-and-tube heat exchanger.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If high drying temperature (300°C) is used to remove ligands during catalyst preparation, then ligand removal is effective, but catalyst structure changes and catalytic performance decreases
Solution Approach 1:
The patent changes the drying temperature parameter from conventional high temperature (300°C) to low temperature (80-120°C) to prevent catalyst structure degradation while effectively removing ligands through the polyoxometalate framework's inherent stability
Solution Approach 2:
The polyoxometalate framework acts as an intermediary structure that enables ligand removal at low temperatures without compromising the catalyst's structural integrity, serving as a protective scaffold during the drying process
2Temperature
If reducing materials (ammonia) are added to control catalytic activity, then hot spot temperature is lowered and reaction efficiency is maintained, but quantitative control during preparation becomes difficult
Solution Approach 1:
The patent extracts the ammonia addition step from the preparation process, achieving temperature control through the polyoxometalate framework's structural design rather than through additive-based chemical control
Solution Approach 2:
The polyoxometalate framework provides self-regulating temperature control through its inherent structural properties, eliminating the need for external reducing materials and their associated control difficulties
3Productivity
If multiple inorganic salts are added to the catalyst precursor, then catalytic activity is enhanced, but the preparation process becomes more complex and requires additional reduction material removal steps
Solution Approach 1:
The patent merges the ligand removal function with the drying process by utilizing the polyoxometalate framework's stability, eliminating the need for separate reduction material removal steps while maintaining enhanced catalytic activity from multiple inorganic salts
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 exhibits superior activity, selectivity, and reproducibility, producing unsaturated carboxylic acids with high yield and long lifespan by controlling vanadium oxidation states and ligand sublimation, and operates effectively over a wider temperature range.
Implementation Method 1
a catalyst used to prepare unsaturated carboxylic acid from unsaturated aldehyde gas through partial vapor-phase oxidation
Implementation Method 2
which may sublimate, during catalyst calcination, ligands included in a catalyst
Data Source
AI summary
Disclosed are a high-performance polyoxometalate catalyst and a method of preparing the same. More particularly, disclosed are a high-performance polyoxometalate catalyst which may enhance activity and selectivity by controlling the content of vanadium, etc. exhibits superior reproducibility, and may produce unsaturated carboxylic acid with high yield and long lifespan from unsaturated aldehyde, and a method of preparing the same.