Magnesium-Modified Zeolite Catalyst for Caprolactam Production
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Solution Overview
Problem
Existing methods for producing ε-caprolactam by Beckmann rearrangement of cyclohexanone oxime in a gas phase using zeolite catalysts suffer from low initial catalytic activity and a decline in activity over time, leading to unsatisfactory productivity.
Innovation Solution
A zeolite catalyst containing a silicon element and at least one alkaline earth metal element, such as calcium, strontium, barium, or magnesium, with a concentration of 3 ppm to 10000 ppm by mass is used to maintain high catalytic activity over a long period.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional zeolite catalysts are used for Beckmann rearrangement, then the process can proceed, but the initial catalytic activity is low and productivity is unsatisfactory
Solution Approach 1:
The patent changes the chemical composition parameters of the zeolite catalyst by incorporating specific alkaline earth metal elements (Ca, Sr, Ba, Mg) at optimized concentrations. This parameter modification transforms the catalyst's properties to achieve both high initial activity and sustained performance over time, directly resolving the productivity-reliability contradiction
Solution Approach 2:
The invention creates a composite catalyst system by combining silicon-containing zeolite with alkaline earth metal elements. This composite structure synergistically enhances both the initial catalytic activity and the long-term stability, enabling sustained high productivity without activity decline
2Duration of action of moving object
If conventional zeolite catalysts are used, then the reaction can proceed, but catalytic activity lowers with the passage of time
Solution Approach 1:
The patent performs preliminary modification of the zeolite catalyst structure by incorporating alkaline earth metal elements before the Beckmann rearrangement reaction. This pre-treatment establishes a stable catalytic framework that maintains consistent activity throughout the reaction duration, preventing the typical activity decline over time
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 method achieves high initial catalytic activity and sustained productivity with enhanced selectivity of ε-caprolactam, maintaining conversion rates above 99% for extended periods.
Implementation Method 1
a method of Beckmann-rearranging cyclohexanone oxime in a gas phase using zeolite as a catalyst
Data Source
Figure 1~2
Figure 3
AI summary
A production method of ε-caprolactam, comprising a step of Beckmann-rearranging cyclohexanone oxime in a gas phase in the presence of a zeolite catalyst containing a silicon element and at least one element selected from the group consisting of alkaline earth metal elements and a magnesium element, wherein the concentration of the above-described element in the zeolite catalyst is 3 ppm by mass or more and 10000 ppm by mass or less.