Rh/C3N4 Catalyst Immobilization for Acetic Acid Carbonylation
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Solution Overview
Problem
Conventional methods for preparing acetic acid through methanol carbonylation reactions, such as the Monsanto and Cativa processes, face challenges with high energy consumption for catalyst recycling and byproduct treatment, and the Acetica process using a heterogeneous catalyst has reduced catalyst activity compared to homogeneous reactions.
Innovation Solution
A heterogeneous catalyst represented by Rh/C3N4 is developed, where a rhodium complex is immobilized on a mesoporous carbon nitride support using 3-benzoylpyridine, enhancing methanol conversion and acetic acid yield while minimizing catalyst loss and energy consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a homogeneous catalyst is used in the Monsanto or Cativa process, then reactant conversion and selectivity are satisfactory, but catalyst recycling is limited and energy consumption for separation and byproduct treatment is high
Solution Approach 1:
The patent introduces a polymer support as an intermediary carrier to immobilize the rhodium catalyst. This mediator enables the catalyst to function in a heterogeneous form, combining the high activity of homogeneous catalysts with the ease of separation of heterogeneous catalysts, thereby resolving the contradiction between conversion efficiency and energy consumption for separation
Solution Approach 2:
The patent employs a polymer support with porous structure to负载 the rhodium catalyst. The porous structure provides large surface area and active sites for catalysis while maintaining the heterogeneous nature of the catalyst, enabling both high reactant conversion and easy separation through filtration or decantation, thus reducing energy consumption
2Loss of energy
If a heterogeneous catalyst with polymer support is used in the Acetica process, then catalyst recycling is improved, but catalyst activity is slightly decreased compared to homogeneous catalysis
Solution Approach 1:
The patent modifies the polymer support parameters including composition, crosslinking degree, and pore structure to optimize catalyst activity. By adjusting these parameters, the patent achieves high catalyst activity comparable to homogeneous catalysis while maintaining the heterogeneous nature for easy recycling, thus resolving the contradiction between energy efficiency and productivity
Solution Approach 2:
The patent creates a composite catalyst system combining rhodium complex with specifically designed polymer support. This composite structure leverages the synergistic effect between the active rhodium species and the polymer matrix, enhancing catalyst activity while maintaining heterogeneous properties for efficient recycling, thereby resolving the contradiction between energy consumption and productivity
3Stability of the object's composition
If the rhodium active component interacts strongly with the support, then catalyst stability and dispersibility are improved, but catalyst activity may be reduced due to limited accessibility of active sites
Solution Approach 1:
The patent applies local quality by creating regions of different interaction strengths between rhodium and polymer support. The polymer support is designed with specific functional groups that provide localized strong interaction sites for anchoring rhodium while maintaining other regions with weaker interactions that preserve rhodium's catalytic activity and accessibility, thus resolving the contradiction between stability and productivity
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 Rh/C3N4 catalyst exhibits high catalytic activity, facilitates easy catalyst separation, and supports stable long-term performance, making it suitable for mass production of acetic acid through methanol carbonylation reactions.
Implementation Method 1
a heterogeneous catalyst represented by Rh/C3N4, configured such that a complex of a rhodium compound and 3-benzoylpyridine is immobilized on a carbon nitride support
Implementation Method 2
the loss of the catalyst may be minimized due to the physical adsorption of the rhodium precious metal onto the polymer support
Data Source
AI summary
This invention relates to a heterogeneous catalyst represented by Rh/C3N4 configured such that a complex of a rhodium compound and 3-benzoylpyridine is immobilized on a carbon nitride support.