Heteropoly Acid Catalyst Thermal Stability
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Solution Overview
Problem
Heteropoly acid catalysts used for the oxidation of unsaturated aldehydes to unsaturated carboxylic acids face challenges with thermal stability, deactivating at operating temperatures due to chemical and physical breakdown, which affects their catalytic performance and lifetime.
Innovation Solution
A heteropoly acid catalyst composition with the formula Mo12VaPbCscBidCueSbfOx, where Mo is molybdenum, V is vanadium, P is phosphorus, Cs is cesium, Bi is bismuth, Cu is copper, Sb is antimony, and O is oxygen, with specific valence ranges, is developed to enhance thermal stability and catalytic performance, incorporating cesium, bismuth, and copper for improved stability and activity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If heteropoly acid compounds are used as catalysts for gas phase oxidation of unsaturated aldehydes, then catalytic activity is achieved, but thermal stability deteriorates causing catalyst deactivation at operating temperatures
Solution Approach 1:
The patent applies composite materials by combining heteropoly acid compounds with specific metal oxides (cesium oxide, bismuth oxide, copper oxide, and antimony oxide) to create a composite catalyst system. This composite structure allows the heteropoly acid to provide catalytic activity while the metal oxide components enhance thermal stability and prevent decomposition at operating temperatures, thereby resolving the contradiction between catalytic activity and thermal stability.
Solution Approach 2:
The patent employs parameter changes by optimizing the molar ratios and concentrations of various metal components in the catalyst composition. By adjusting the proportions of heteropoly acid, cesium, bismuth, copper, and antimony, the catalyst achieves both high catalytic activity and improved thermal stability, preventing deactivation while maintaining effectiveness for the oxidation reaction.
2Productivity
If process operating temperatures are used for oxidation reactions, then reaction rate and productivity are improved, but catalyst deactivation occurs due to chemical and physical breakdown
Solution Approach 1:
The patent applies beforehand cushioning by incorporating thermally stable metal oxide components (cesium oxide, bismuth oxide, copper oxide, and antimony oxide) into the catalyst structure before operation. These components act as structural supports and stabilizers that prevent premature decomposition of the heteropoly acid framework, cushioning against thermal stress and chemical degradation during high-temperature oxidation reactions, thus extending catalyst lifetime while maintaining high 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 catalyst composition exhibits high thermal stability and catalytic performance, maintaining activity and selectivity even at elevated temperatures, outperforming existing catalysts by preventing structural degradation and maintaining performance across a wide range of calcination temperatures.
Implementation Method 1
Heteropoly acid compounds are also known as catalysts for the gas phase catalytic oxidation of unsaturated aldehydes to unsaturated carboxylic acids
Implementation Method 2
Presence of cesium along with bismuth, copper and antimony is required for a heteropoly acid compound catalyst with good thermal stability
Data Source
AI summary
The invention is a heteropoly acid compound catalyst composition, a method of making the catalyst composition and a process for the oxidation of saturated and/or unsaturated aldehydes to unsaturated carboxylic acids using the catalyst composition. The catalyst composition is a heteropoly acid compound containing molybdenum, vanadium, phosphorus, cesium, bismuth, copper and antimony. Thermal stability is achieved with higher cesium content (up to less than 3.0) but antimony, copper and bismuth must be present to maintain good activity.The catalyst is made by dissolving compounds of the components of each of the heteropoly acid compounds in a solution, precipitating the heteropoly acid compounds, obtaining a catalyst precursor and calcining the catalyst precursor to form a heteropoly acid compound catalyst.Unsaturated aldehydes, such as methacrolein, may be oxidized in the presence of the heteropoly acid compound catalyst to produce an unsaturated carboxylic acid, such as methacrylic acid.