VPO Catalyst ZnO Shaped Body Selectivity Stability
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Solution Overview
Problem
VPO catalysts used for the oxidation of butane to maleic anhydride have low intrinsic activity and high costs due to expensive starting materials, requiring large amounts and needing improvements in activity, selectivity, and mechanical stability.
Innovation Solution
A VPO catalyst in the form of a shaped body with 0.05% to 7.0% Zn, primarily as ZnO, exhibiting specific infrared and X-ray diffraction characteristics, and having enhanced mechanical strength through the addition of ZnO, which stabilizes the catalyst particles and improves catalytic performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If VPO catalyst is used for oxidation of butane to maleic anhydride, then catalytic activity is achieved, but intrinsic activity is low requiring large amounts of catalyst
Solution Approach 1:
The patent modifies the chemical composition parameters of the VPO catalyst by incorporating zinc oxide and adjusting the vanadium phosphorus oxide phase composition. This changes the catalytic properties to achieve higher intrinsic activity, thereby reducing the quantity of catalyst needed while maintaining or improving productivity.
Solution Approach 2:
The patent creates a composite catalyst system combining VPO phase with zinc oxide and other metal oxides (such as molybdenum, lithium, or sodium). This composite structure synergistically enhances the catalytic activity beyond what pure VPO can achieve, allowing reduced catalyst quantity for the same productivity level.
2Productivity
If VPO catalyst is used for oxidation reactions, then catalytic function is achieved, but selectivity needs improvement
Solution Approach 1:
The patent adjusts the chemical composition parameters including zinc oxide content (0.1-5.0 wt%), molybdenum content (0.01-1.0 wt%), and vanadium phosphorus oxide phase composition. These parameter changes optimize the catalyst's selectivity toward maleic anhydride while minimizing unwanted byproducts through controlled chemical transformations.
Solution Approach 2:
The patent introduces specific local chemical environments within the catalyst structure by incorporating zinc oxide and other promoters at controlled concentrations. These localized modifications create specific active sites that favor the desired oxidation pathway to maleic anhydride, improving selectivity by enhancing local reaction conditions.
3Productivity
If VPO catalyst is used for industrial application, then catalytic performance is achieved, but mechanical stability is insufficient
Solution Approach 1:
The patent creates a composite catalyst formulation combining VPO phase with zinc oxide and other metal oxides that not only enhance catalytic performance but also improve mechanical stability. The composite structure provides both chemical activity and physical robustness needed for industrial applications.
Solution Approach 2:
The patent optimizes physical and chemical parameters including particle size distribution, surface area (3-15 m²/g), and composition ratios to achieve a balance between catalytic performance and mechanical stability. These parameter adjustments ensure the catalyst maintains its structural integrity under industrial operating conditions while delivering high performance.
Data Source
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AI summary
The invention relates to a VPO catalyst in the form of a shaped body for oxidation of hydrocarbons with molecular oxygen, especially for oxidation of butane to maleic anhydride with molecular oxygen, wherein the VPO catalyst contains 0.05% by weight to 7.0% by weight of Zn, partly in the form of ZnO, and, in transmission infrared spectroscopy, has a first absorption band having a maximum between 790 cm-1 and 810 cm-1 and possibly a second absorption band having a maximum between 820 cm-1 and 840 cm-1, characterized in that only the first absorption band is present or the intensity of the first absorption band is greater than the intensity of the second absorption band. The invention further relates to a process for producing a VPO catalyst of the invention, comprising the steps of: a) producing a catalyst precursor containing vanadyl hydrogenphosphate, b) forming the catalyst precursor to a shaped body, c) activating the shaped bodies in order to form a VPO phase, characterized in that, after step a), ZnO is mixed with the catalyst precursor.