Heterogeneous Catalyst Preparation for Ethylene Oligomerization
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Solution Overview
Problem
Existing industrial processes for producing linear alpha-olefins through ethylene oligomerization face challenges such as large heat release, difficult product separation, and the need for expensive co-catalysts like sodium borohydride or aluminum alkoxide, which reduce selectivity and increase production costs.
Innovation Solution
A novel process for preparing a catalyst by loading a transition metal salt and a bidentate ligand onto a molecular sieve using a fixed bed reactor, where the transition metal is reduced from a first valence state to a second valence state by an active metal promoter, facilitating efficient ethylene oligomerization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If homogeneous catalysts with co-catalysts like sodium borohydride or aluminum alkoxide are used, then catalytic activity is achieved, but production cost increases and selectivity decreases
Solution Approach 1:
The patent extracts and removes the expensive co-catalysts (sodium borohydride, aluminum alkoxide) from the catalytic system while retaining the essential function of the transition metal catalyst. The heterogeneous catalyst system achieves catalytic activity through the transition metal complex immobilized on the support, eliminating the need for additional co-catalysts and thereby reducing production costs.
Solution Approach 2:
The patent changes the physical state and composition parameters of the catalyst system by transitioning from homogeneous to heterogeneous catalysis. This parameter change allows the catalyst to function without expensive co-catalysts, improving both economic viability and selectivity while maintaining catalytic activity.
2Reliability
If homogeneous catalysts are used, then catalytic activity is achieved, but product separation becomes difficult
Solution Approach 1:
The patent extracts the catalyst from the homogeneous phase and immobilizes it on a solid support, creating a heterogeneous system. This extraction allows for easy separation of the catalyst from the product mixture through simple filtration or decantation, eliminating the complex separation procedures required for homogeneous catalysts while preserving catalytic activity.
Solution Approach 2:
The solid support acts as an intermediary carrier that holds the transition metal catalyst. This intermediary enables the catalyst to function in a heterogeneous manner, facilitating easy separation from the liquid or gaseous reaction mixture while maintaining the catalytic function.
3Productivity
If conventional oligomerization processes are used, then linear alpha-olefin is produced, but large heat release occurs
Solution Approach 1:
The patent employs a porous solid support material to carry the catalyst. The porous structure provides large surface area for catalytic activity while the solid matrix facilitates heat dissipation. This allows the exothermic oligomerization reaction to proceed with improved heat management, preventing thermal runaways while maintaining high 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
This process enables the production of heterogeneous catalysts with equal or higher activity and selectivity compared to homogeneous catalysts, while avoiding the use of expensive co-catalysts and improving heat diffusion and catalyst separation.
Implementation Method 1
loading the transition metal onto the molecular sieve through ion exchange
Implementation Method 2
the transition metal in the first valence state at least partially being reduced into a transition metal salt in a second valence state by the active metal promoter
Implementation Method 3
a process for preparing linear alpha-olefin by oligomerization of ethylene by using a transition metal ligand catalyst immobilized on a support
Data Source
AI summary
The present invention relates to a process for preparing a catalyst, wherein the process comprises steps of: 1) providing a molecular sieve, adding an active metal promoter into the molecular sieve, and shaping the molecular sieve into a shaped body, 2) placing the shaped body in a fixed bed reactor, 3) dissolving a transition metal salt in a first valence state and a bidentate ligand into a solvent to prepare a solution, 4) passing the solution and ethylene through the fixed bed reactor charged with the shaped body, loading the transition metal onto the molecular sieve through ion exchange, and at the same time the transition metal in the first valence state at least partially being reduced into a transition metal salt in a second valence state by the active metal promoter, wherein the second valence state is lower than the first valence state, so as to obtain the catalyst.