Silicon-Aluminium Oxide Olefin Isomerization with Low Oligomerization
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Solution Overview
Problem
Existing catalyst systems are limited in isomerizing olefins with a terminal double bond to those with an internal double bond, and they promote side reactions like oligomerization, especially when using acidic catalysts.
Innovation Solution
A silicon-aluminium mixed oxide catalyst with specific compositions and properties, produced by flame hydrolysis, is used to isomerize C4 to C9 olefins with a terminal double bond to those with an internal double bond, minimizing side reactions and maintaining high selectivity and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If acidic catalyst systems are used for isomerization, then isomerization activity is improved, but oligomerization side reactions increase
Solution Approach 1:
The patent changes the chemical parameter of the catalyst from strongly acidic to weakly acidic by using silicon-aluminum mixed oxides with controlled Al2O3 content (0.01-4% by weight). This parameter change allows the catalyst to provide sufficient isomerization activity while suppressing oligomerization side reactions that occur with stronger acidic catalysts
Solution Approach 2:
The patent uses a composite catalyst material consisting of silicon oxide and aluminium oxide in specific proportions. This composite structure combines the benefits of SiO2 (low acidity, high stability) with Al2O3 (moderate acidity, good activity), achieving a balance between isomerization activity and suppression of harmful side reactions
2Object-generated harmful factors
If basic catalyst systems are used to prevent oligomerization, then side reactions are reduced, but isomerization activity decreases
Solution Approach 1:
The patent optimizes the acidity parameter by using weakly acidic silicon-aluminum mixed oxides instead of strongly acidic or basic catalysts. The controlled Al2O3 content (0.01-4% by weight) provides just enough acid sites for isomerization activity while avoiding the excessive acidity that causes oligomerization, eliminating the need to choose between activity and side reaction suppression
3Productivity
If high temperatures are used to increase conversion rate, then isomerization speed is improved, but catalyst stability decreases
Solution Approach 1:
The patent changes the temperature parameter from high to low operating conditions. The weakly acidic silicon-aluminum mixed oxide catalyst maintains high isomerization activity at low temperatures, which in turn preserves catalyst stability and extends catalyst life, avoiding the deactivation problems associated with high-temperature operation
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 catalyst achieves high selectivity and stability for isomerizing olefins, with minimal oligomerization, allowing efficient conversion at low temperatures and extended catalyst life.
Implementation Method 1
a heterogeneous catalyst which comprises a silicon-aluminium mixed oxide composition is used
Implementation Method 2
causing the silicon and aluminium compounds to be hydrolysed by means of the water formed in the oxyhydrogen flame
Data Source
AI summary
The invention provides a process for the isomerization of C4 to C9 olefins having a terminal double bond to the corresponding olefins having an internal double bond, wherein a heterogeneous catalyst which comprises a silicon-aluminium mixed oxide composition is used.