Mo-Fe-Al-P Oxide Catalyst for Low-Temperature Methanol Oxidation
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Solution Overview
Problem
Existing catalysts for methanol oxidation to formaldehyde suffer from low activity, high reaction temperatures, and instability, leading to reduced catalyst life and insufficient formaldehyde selectivity.
Innovation Solution
A catalyst with the formula MoFe a Al b P c O x, where a=0.25-0.5, b=0.001-0.2, and c=0.001-0.6, prepared by mixing molybdenum, iron, aluminum, and phosphoric acid solutions, followed by aging, drying, and calcination, enables lower reaction temperatures and improved stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the reaction temperature is raised to ensure high methanol conversion (>98.5%), then the methanol conversion is improved, but the molybdenum in the catalyst sublimes and runs off, causing further decline in catalyst activity
Solution Approach 1:
The patent changes the chemical composition parameters of the catalyst by introducing aluminum and phosphorus elements in specific ratios (a=0.25-0.5, b=0.001-0.2, c=0.001-0.6), which modifies the catalyst's properties to achieve high methanol conversion at lower temperatures, thereby preventing molybdenum sublimation and improving catalyst stability
Solution Approach 2:
The patent creates a composite oxide catalyst containing molybdenum, iron, aluminum, and phosphorus (MoFe a Al b P c O x) where the synergistic interaction between these elements enhances catalyst activity and stability, allowing operation at lower temperatures while maintaining high conversion rates
2Productivity
If the reaction temperature is raised to improve catalyst activity, then the methanol conversion is improved, but the formaldehyde selectivity decreases and by-products increase
Solution Approach 1:
The patent optimizes the chemical composition parameters of the catalyst by controlling the ratios of a, b, and c in the formula MoFe a Al b P c O x, which creates an optimal catalytic environment for selective formaldehyde production at lower temperatures, preventing over-oxidation to CO and CO2
Solution Approach 2:
The patent introduces aluminum and phosphorus elements that create specific local active sites on the catalyst surface with optimized electronic and geometric properties, enhancing the selectivity toward formaldehyde while maintaining high conversion activity
3Quantity of substance
If existing iron-molybdenum catalysts are used, then the process can produce highly concentrated formaldehyde, but the catalyst activity is low and requires high reaction temperatures
Solution Approach 1:
The patent develops a multi-element composite catalyst (MoFe a Al b P c O x) that combines the formaldehyde production capability of iron-molybdenum with the activity-enhancing properties of aluminum and phosphorus, achieving both high formaldehyde concentration and high catalyst activity at lower temperatures
Solution Approach 2:
The patent modifies the catalyst composition parameters by introducing Al and P elements in controlled amounts, which enhances the catalytic activity and lowers the operating temperature while maintaining the ability to produce highly concentrated formaldehyde
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 methanol conversion (98.5%) with stable formaldehyde selectivity (96.0-97.0%) at reduced temperatures (220-261°C), maintaining activity over extended periods.
Implementation Method 1
a catalyst for catalytic selective oxidation of methanol to formaldehyde with low reaction temperature and steady activity
Implementation Method 2
followed by firing
Implementation Method 3
calcination
Data Source
AI summary
Disclosed are a composite oxide catalyst, a preparation method therefor, and a use thereof. The catalyst has the following general formula: MoFeaAlbPcOx, wherein a=0.25-0.5, b=0.001-0.2, c=0.001-0.6, and x is a number satisfying the valence of the general formula. The catalyst of the present invention has excellent low-temperature performance and thus has a long service life.