Mixed Metal Oxide Catalyst Preparation with Nitrogen Precursor
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Solution Overview
Problem
Existing catalysts for the ammoxidation of propylene and isobutylene to produce nitriles and oxidation to acrolein/acrylic acid have limitations in conversion efficiency and ammonia utilization, with typical bismuth-molybdenum-iron catalysts not effectively utilizing ammonia to produce valuable nitrile products.
Innovation Solution
A process for preparing a mixed metal oxide catalyst with a specific complex composition, including a heat-decomposable nitrogen-containing compound added during catalyst preparation, which enhances the conversion of propylene and isobutylene to nitriles and improves ammonia utilization efficiency by calculating the relative ratios of elements like Mo, Bi, Fe, and Ce, and incorporating elements such as sodium, potassium, and nickel, and calcining the catalyst particles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional bismuth-molybdenum-iron catalysts are used for ammoxidation, then the catalyst structure is simple and easy to manufacture, but the ammonia utilization efficiency is low and conversion to nitriles is limited
Solution Approach 1:
The patent applies preliminary action by adding a heat-decomposable nitrogen-containing compound during catalyst preparation before calcination. This preliminary incorporation of nitrogen sources into the catalyst structure enables improved ammonia utilization efficiency and higher nitrile conversion during actual operation, without complicating the overall manufacturing process
Solution Approach 2:
The patent changes the chemical composition parameters of the catalyst by incorporating heat-decomposable nitrogen-containing compounds and adjusting the ratios of metal oxides (Bi, Mo, Fe, Ce, Na, K, Ni). These parameter changes transform the catalyst's ability to utilize ammonia, achieving nitrogen insertion measures greater than 100 and significantly improving conversion to valuable nitrile products
2Productivity
If complex multiple-step catalyst preparation processes are used, then catalyst performance improves, but manufacturing complexity and process time increase
Solution Approach 1:
The patent merges the nitrogen incorporation step with the existing catalyst preparation process by adding heat-decomposable nitrogen-containing compounds during the mixing or drying stages before calcination. This consolidation achieves improved ammonia utilization efficiency without requiring separate additional process steps, thereby reducing overall preparation time
3Productivity
If conventional catalysts are used, then the process is simple to operate, but valuable nitrile products are not produced efficiently with low nitrogen insertion
Solution Approach 1:
The patent applies preliminary action by pre-incorporating nitrogen-containing compounds into the catalyst structure before use. This preliminary nitrogen incorporation enables the catalyst to achieve nitrogen insertion measures greater than 100 during ammoxidation, efficiently producing valuable nitrile products without complicating the operational process
Solution Approach 2:
The patent creates a composite catalyst material combining metal oxides (Bi, Mo, Fe, Ce, Na, K, Ni) with heat-decomposable nitrogen-containing compounds. This composite structure enhances the catalyst's ability to insert nitrogen into propylene, achieving high nitrogen insertion measures and efficient nitrile production while maintaining reasonable compositional complexity
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 higher overall conversion of propylene to nitriles, such as acrylonitrile and hydrogen cyanide, with improved ammonia utilization efficiency, characterized by a nitrogen insertion measure (α) greater than 100 and low ammonia burn, indicating efficient production of valuable products while minimizing by-products.
Implementation Method 1
a heat-decomposable nitrogen containing compound is added during the preparation of the catalyst prior to a calcination step
Implementation Method 2
Catalysts containing oxides of iron, bismuth and molybdenum, promoted with suitable elements, have long been used for the conversion of propylene and/or isobutylene at elevated temperatures in the presence of ammonia and oxygen
Implementation Method 3
combining source compounds of the metals which comprise the metal oxide catalyst to form a catalyst precursor, drying the catalyst precursor to form catalyst particles, and calcining the catalyst particles to yield the catalyst
Data Source
AI summary
A process for preparation of catalysts for the production of acrylonitrile, acetonitrile and hydrogen cyanide comprising contacting at an elevated temperature, propylene, ammonia and oxygen in the vapor phase in the presence of a catalyst, said catalyst comprising a complex of metal oxides wherein a heat-decomposable nitrogen containing compound is added during the process for the preparation of the catalyst.