Immobilized Mo-W Catalysts for Olefin Cross Metathesis
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Solution Overview
Problem
Current methods for olefin cross metathesis, particularly for producing propylene from 2-butene and ethylene, face challenges in scalability and catalyst recovery, with existing catalysts often requiring complex separation processes that damage their activity.
Innovation Solution
The use of immobilized silica-supported molybdenum-alkylidene or tungsten-alkylidene catalysts allows for the simple separation of catalysts from reaction mixtures via filtration or centrifugation, enabling their reuse in olefin metathesis reactions, particularly in cross metathesis between different olefins.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If homogeneous catalysis is used for olefin cross metathesis, then catalytic activity is achieved, but catalyst separation requires complex processing and catalyst activity is deteriorated
Solution Approach 1:
The catalyst system is segmented into two distinct parts: the active catalytic species (molybdenum or tungsten alkylidene complex) and the solid support (silica). This segmentation allows the catalyst to function as a homogeneous catalytic system for high activity while being physically separable as a heterogeneous system through simple filtration or centrifugation, eliminating complex separation processing and preserving catalyst activity for reuse.
Solution Approach 2:
A solid support (silica) is introduced as an intermediary carrier that anchors the catalytic complex. This intermediary allows the catalyst to maintain its active homogeneous catalytic properties while gaining the physical separability and reusability of heterogeneous catalysts. The support acts as a mediator that enables simple separation through filtration or centrifugation without damaging the catalyst's active sites.
2Duration of action of stationary object
If catalyst is separated from reaction mixture, then catalyst can be reused, but catalyst activity is destroyed or considerably deteriorated
Solution Approach 1:
By segmenting the catalyst into a soluble catalytic complex anchored on an insoluble support, the system enables complete separation of the catalyst from the reaction mixture through simple filtration or centrifugation. The segmented structure ensures that the catalytic active sites remain intact and accessible on the support surface, preventing activity loss during separation and enabling successful reuse in subsequent reactions.
Solution Approach 2:
The solid support serves as a protective intermediary that shields the catalytic complex from degradation during separation processes. The support matrix maintains the structural integrity and chemical stability of the catalytic sites, ensuring that catalyst activity is preserved while enabling repeated separation and reuse cycles without significant activity loss.
3Ease of operation
If simple separation method is used, then catalyst recovery is easy, but catalyst activity may be compromised
Solution Approach 1:
The catalyst system is segmented into a finely divided catalytic complex and a solid support, creating a size-based separation opportunity. This segmentation enables extremely simple separation through basic filtration or centrifugation operations, while the segmented structure ensures that the catalytic active sites remain intact on the support surface, preventing activity compromise during the simple separation process.
Solution Approach 2:
The solid support acts as a protective intermediary that allows simple separation operations to be performed without compromising catalyst activity. The support matrix is designed to maintain the structural and chemical integrity of the catalytic complexes during handling and separation, ensuring that even simple filtration or centrifugation does not damage the active sites or reduce catalyst performance.
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 method facilitates the efficient production of propylene at an industrial scale by maintaining catalyst activity and allowing for easy recovery and reuse, enhancing the scalability and economic viability of olefin cross metathesis processes.
Implementation Method 1
The invention relates to immobilized molybdenum and tungsten catalysts. Said catalysts may be used in olefin cross metathesis.
Data Source
AI summary
Method of forming an olefin from a first olefin and a second olefin in a metathesis reaction, comprising step (i): (i) reacting the first olefin with the second olefin in the presence of a silica supported Mo- or W-alkylidene catalyst, wherein the first olefin and the second olefin are different from one another.