Molybdenum Composite Oxide Catalyst for Butadiene via Ball Milling
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Solution Overview
Problem
Current methods for preparing molybdenum based oxide catalysts for butadiene production by oxidative dehydrogenation of butene face challenges such as poor repeatability, active ingredient loss, and generation of waste water and gases, which hinder industrial scalability and efficiency.
Innovation Solution
A molybdenum based composite oxide catalyst with the formula BiMoxMyNzOa, where M includes V, Cr, Mn, Fe, Co, Ni, or Cu, and N includes Na, K, Cs, Ca, or Ba, is prepared using a ball milling method that ensures uniform distribution of metal ions and reduces waste, enhancing catalytic activity and selectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the direct drying method is used to prepare the catalyst, then the preparation process is simple, but different metal elements isolate during drying resulting in poor uniformity and complicated crystal phase structure
Solution Approach 1:
The patent applies preliminary action by performing high-energy ball milling of metal oxide precursors before the actual catalyst formation process. This pre-mixing step ensures that different metal elements (Bi, Mo, Fe, Co, Ni, Zn) are uniformly distributed at the nanoscale level before drying and calcination, preventing isolation during subsequent processing steps and ensuring consistent crystal phase structure throughout the catalyst.
2Ease of manufacture
If the direct drying method is used, then the process is simple, but a large amount of waste gases containing nitrogen and chlorine are produced
Solution Approach 1:
The patent changes the chemical composition parameters of the catalyst by replacing traditional nitrogen-based and chlorine-based precursors with oxide precursors. This parameter change eliminates the formation of harmful nitrogen and chlorine-containing waste gases during the drying and firing processes, while still achieving the desired catalyst composition and activity through controlled oxidation during calcination.
3Productivity
If the co-precipitation method is used, then the activity of multi-component bismuth molybdate catalyst is enhanced, but metal ions form complex compounds with ammonium ion resulting in active ingredient loss
Solution Approach 1:
The patent uses high-energy ball milling as an intermediary process between precursor preparation and catalyst formation. This mechanical activation step disperses metal oxide precursors at the nanoscale and creates highly reactive surfaces that facilitate uniform catalyst formation without requiring ammonium ion intermediaries, thereby preventing complex compound formation and active ingredient loss while maintaining high catalytic activity.
4Productivity
If the co-precipitation method is used, then catalyst activity is enhanced, but metal ion-containing waste water is produced requiring special treatment
Solution Approach 1:
The patent changes the preparation approach from wet chemical co-precipitation (which generates metal ion-containing waste water) to a dry high-energy ball milling method using oxide precursors. This parameter change in the preparation process eliminates aqueous waste streams containing metal ions, requiring no special waste water treatment, while still producing highly active catalysts through mechanical activation and controlled calcination.
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 high conversion rates of butene (80-98%) and selectivity for butadiene (90-97%), with improved repeatability and reduced waste production, outperforming conventional methods like co-precipitation and direct drying.
Implementation Method 1
transferring the mixture to a ball mill jar, ball milling same to produce the desired molybdenum based composite oxide catalyst
Implementation Method 2
The catalyst exhibits high conversion rates of butene (80-98%) and selectivity for butadiene (90-97%), outperforming conventional methods like co-precipitation and direct drying
Data Source
AI summary
Disclosed are a molybdenum based composite oxide catalyst, its preparation method and use. The catalyst has the following general formula: BiMoxMyNzOa; wherein M is one of V, Cr, Mn, Fe, Co, Ni and Cu, or a mixture of two or more of V, Cr, Mn, Fe, Co, Ni and Cu in any ratio; N is one of Na, K, Cs, Ca and Ba, or a mixture of two or more of Na, K, Cs, Ca and Ba in any ratio; x=0.5˜20; y=0.05˜20; z=0.01˜5; a is a number satisfying the valance of each atom. The catalyst is prepared by the following method: firstly mixing a certain amount of the lead metal oxides according to the chemical proportion and then grinding the mixture with high-energy ball milling for a period of time to obtain the molybdenum based composite oxide catalyst. The catalyst exhibits excellent performance when using for preparation of butadiene by oxidative dehydrogenation of butene, and the preparation process is simple, controllable, and repeatable. Waste water or waste gas that is difficult to be treated is not produced during preparation.