Moisture-Modified Silicoaluminophosphate Catalyst for Methylamine Synthesis
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Solution Overview
Problem
Existing methods for producing methylamine compounds using crystalline silicoaluminophosphate salt molecular sieves face challenges in maintaining high dimethylamine selectivity and long-term catalytic activity, with conventional modification methods being inefficient and sacrificing catalytic activity for improved selectivity.
Innovation Solution
A method involving the adsorption of moisture onto a crystalline silicoaluminophosphate salt molecular sieve followed by thermal modification under controlled conditions of temperature and pressure, specifically 130 to 200°C and 0.1 MPa for 5 to 40 hours, to create a modified catalyst with improved dimethylamine selectivity and sustained activity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional water vapor treatment is applied to modify the catalyst, then dimethylamine selectivity is improved, but catalytic activity is sacrificed
Solution Approach 1:
The invention changes the treatment parameters from conventional water vapor treatment at high temperatures (600-900°C) to a two-step process: first adsorbing controlled amounts of water (5-30 wt%) at lower temperatures, then heating at moderate temperatures (130-200°C) under pressure (0.1 MPa or more) for extended periods (5-40 hours). This parameter transformation achieves homogeneous modification that improves both selectivity and maintains activity, resolving the trade-off between the two properties.
Solution Approach 2:
The invention applies preliminary action by first adsorbing a controlled amount of water onto the catalyst surface before applying thermal treatment. This preliminary water adsorption step creates optimal conditions for subsequent moderate-temperature heating, enabling homogeneous modification without the need for high-temperature water vapor treatment that would otherwise damage catalytic activity. The preliminary water uptake prepares the catalyst structure for gentle thermal modification.
2Stability of the object's composition
If high-temperature water vapor treatment is applied, then catalyst modification is achieved, but treatment conditions become harsh and activity is reduced
Solution Approach 1:
The invention transforms the treatment parameters from high temperature (600-900°C) to moderate temperature (130-200°C) combined with pressure application (0.1 MPa or more) and extended treatment time (5-40 hours). This parameter substitution achieves the required catalyst modification while avoiding the harsh conditions that would reduce catalytic activity. The pressure and time parameters compensate for the lower temperature, maintaining modification effectiveness.
3Manufacturing precision
If conventional modification methods are used, then selectivity is improved, but long-term stability of catalytic performance is insufficient
Solution Approach 1:
The invention applies preliminary water adsorption (5-30 wt%) to prepare the catalyst structure before moderate-temperature thermal treatment. This preliminary action creates a stable modified structure that maintains both high selectivity and long-term catalytic activity. The controlled water uptake at the preliminary stage prevents structural damage that would otherwise occur during harsh treatment, ensuring long-term stability.
Solution Approach 2:
By changing from high-temperature short-duration treatment to moderate-temperature long-duration treatment under pressure, the invention achieves more stable catalyst modification. The extended treatment time (5-40 hours) at moderate temperatures with pressure application allows for gradual, uniform structural changes that enhance long-term stability while maintaining high selectivity and activity.
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
This approach homogeneously modifies the catalyst, enhancing both activity and selectivity in methylamine synthesis reactions, maintaining performance over a long period with milder conditions compared to conventional methods.
Implementation Method 1
adsorbing moisture onto a crystalline silicoaluminophosphate salt molecular sieve
Implementation Method 2
heating it under a pressure of 0.1 MPa or more and at a temperature of 130 to 200°C for 5 to 40 hours
Data Source
AI summary
According to the present invention, a method for producing a catalyst for use in the production of a methylamine compound can be provided, wherein the catalyst comprises a modified crystalline silicoaluminophosphate salt molecular sieve. The method comprises: a moisture control step of adsorbing moisture onto a crystalline silicoaluminophosphate salt molecular sieve in an amount of 5 to 30 wt% of the crystalline silicoaluminophosphate salt molecular sieve; and a step of heating the crystalline silicoaluminophosphate salt molecular sieve having moisture adsorbed thereon under a pressure of 0.1 MPa or more and at a temperature of 130 to 350°C for 5 to 40 hours.