Silyl-Modified Metal Oxide Carrier for Long-Chain Olefin Epoxidation
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Solution Overview
Problem
Existing methods for epoxidizing olefins using hydrogen peroxide and solid oxidation catalysts face challenges with low conversion rates and selectivity, particularly when olefins have long carbon chains.
Innovation Solution
A method involving a solid oxidation catalyst with a transition metal supported on a metal oxide carrier having a silyl group, where the carrier is a metal oxide with a silyl group represented by R1R2R3Si—, and the transition metal is preferably tungsten, is used to enhance catalytic activity and achieve high yield and selectivity for epoxides.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a conventional epoxidation catalyst (heteropolyacid with surface-treated carrier) is used, then short-chain olefins achieve high conversion rate and selectivity, but long-chain olefins show greatly reduced catalytic activity and olefin conversion rate
Solution Approach 1:
The invention changes the chemical parameters of the carrier surface by introducing silyl groups with specific hydrocarbon chains (at least one of R1, R2, R3 being a hydrocarbon group with 3 or more carbon atoms). This modification alters the surface properties to enhance interaction with long-chain olefins, thereby maintaining high catalytic activity and selectivity across different olefin chain lengths while achieving high conversion rates
Solution Approach 2:
The invention creates a composite catalyst system combining transition metal (tungsten) with a modified metal oxide carrier that has silyl groups grafted onto its surface. This composite structure integrates the oxidative capability of tungsten with the enhanced olefin interaction properties of the silyl-modified carrier, resolving the contradiction between conversion rate and adaptability to different chain lengths
2Manufacturing precision
If existing solid oxidation catalysts are used for epoxidation, then the process can proceed, but both olefin conversion rate and selectivity for epoxides remain low
Solution Approach 1:
The invention applies local quality modification by introducing silyl groups specifically on the carrier surface that interact with the olefin substrates. The hydrocarbon groups in the silyl moieties create localized hydrophobic regions that preferentially interact with the olefin double bonds, enhancing both selectivity for epoxide formation and conversion rate simultaneously
Solution Approach 2:
The silyl-modified carrier acts as an intermediary between the transition metal active sites and the olefin substrates. The hydrocarbon groups in the silyl groups facilitate substrate adsorption and orientation, while the metal sites perform the oxidation, thereby achieving both high conversion and high selectivity through cooperative catalysis
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 enables high olefin conversion rates and selectivity for epoxides even with long-chain olefins, improving the efficiency of the epoxidation process.
Implementation Method 1
reacting an olefin with an oxidant in the presence of a solid oxidation catalyst, wherein the solid oxidation catalyst comprises a transition metal and a carrier that supports the transition metal
Implementation Method 2
the carrier is a metal oxide having a silyl group represented by the following general formula (1): R1R2R3Si—
Data Source
AI summary
The present invention provides: a method for producing an epoxyalkane capable of obtaining an epoxide in a high yield while attaining a high olefin conversion rate and a high selectivity for epoxides even when an olefin includes a long carbon chain, and a solid oxidation catalyst used in the method. The method for producing an epoxyalkane of the present invention comprises reacting an olefin with an oxidant in the presence of a solid oxidation catalyst, wherein the solid oxidation catalyst comprises a transition metal and a carrier that supports the transition metal, and the carrier is a metal oxide having a silyl group represented by the following general formula (1):R1R2R3Si— (1)wherein R1, R2, and R3 are each independently a single bond, a hydrocarbon group, a halogenated hydrocarbon group, an alkoxy group, or a halogen, and at least one of R1, R2, and R3 is a hydrocarbon group having 3 or more carbon atoms or a halogenated hydrocarbon group having 3 or more carbon atoms.