Olefin Production via Alcohol Dehydration with Aluminum Oxide Catalyst
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Solution Overview
Problem
Existing methods for producing olefins through dehydration reactions face challenges such as difficulty in controlling reactions, reduced yields due to oligomerization, and insufficient suppression of by-products, particularly when using mixtures of alcohols with different carbon chain lengths.
Innovation Solution
A method involving a liquid phase dehydration reaction of primary aliphatic alcohols with 8 to 22 carbon atoms using an acid catalyst containing aluminum oxide, specifically a solid acid catalyst with a high ratio of weak acid sites, to suppress oligomerization and enhance yield.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a silica alumina catalyst is used for dehydration reaction, then the reaction can proceed, but oligomerized products are formed and yield is reduced
Solution Approach 1:
The patent changes the catalyst parameters from conventional silica alumina to a specifically designed solid acid catalyst with controlled acid site distribution (weak acid sites: 30-70 μmol/g, strong acid sites: 0.1-3.0 μmol/g). This parameter change in catalyst acidity suppresses oligomerization while maintaining dehydration reaction efficiency, resolving the contradiction between productivity and harmful by-products.
Solution Approach 2:
The patent applies local quality by creating a catalyst with non-uniform acid site distribution, where weak acid sites are predominant and strong acid sites are minimized. This local differentiation in acid strength across the catalyst surface allows selective promotion of desired dehydration reaction while suppressing oligomerization pathways that require stronger acid sites.
2Productivity
If trifluoromethanesulfonic acid is used as catalyst, then dehydration reaction occurs, but reaction control becomes difficult
Solution Approach 1:
The patent replaces the liquid acid catalyst (trifluoromethanesulfonic acid) with a solid acid catalyst that can be easily separated and reused. The solid catalyst performs the dehydration function effectively but can be filtered out and regenerated, making the reaction easier to control and the catalyst reusable, thus resolving the control difficulty while maintaining productivity.
Solution Approach 2:
The solid acid catalyst acts as an intermediary that facilitates the dehydration reaction without requiring the reactants to be in direct contact with the liquid acid. The solid catalyst surface provides the necessary acid sites for reaction while allowing easy separation, improving reaction control compared to liquid acid systems.
3Adaptability or versatility
If mixture of alcohols with different carbon chain lengths is used, then product diversity increases, but yield reduction occurs due to oligomerization
Solution Approach 1:
The patent changes the catalyst acid site parameters to have a specific distribution profile (predominantly weak acid sites with controlled strong acid sites) that is optimized for handling mixed alcohol feedstocks. This parameter optimization allows the catalyst to process various carbon chain lengths effectively while suppressing oligomerization, thus maintaining both product diversity and high yield.
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 effectively produces olefins with high yield while minimizing oligomerization, improving reaction control and selectivity, and maintaining catalyst efficiency.
Implementation Method 1
subjecting a raw material alcohol to dehydration reaction in the presence of an acid catalyst, the acid catalyst containing a metal oxide containing aluminum
Implementation Method 2
a reaction temperature being 200°C or more and 300°C or less, wherein the dehydration reaction is liquid phase reaction
Data Source
AI summary
A method for producing an olefin, containing subjecting a raw material alcohol to dehydration reaction in the presence of an acid catalyst, in which the acid catalyst contains a metal oxide, the raw material alcohol contains two or more kinds of alcohols having different numbers of carbon atoms each being a primary aliphatic alcohol having 8 or more and 22 or less carbon atoms, and a temperature of the reaction is 200°C or more and 300°C or less.