Mixed Metal Oxide Catalyst Support for Propylene Dimerization
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Solution Overview
Problem
Catalysts for dimerization of olefins, particularly those using alkali metal on carbonate supports, suffer from long induction times and structural degradation, limiting their effectiveness and selectivity in producing branched aliphatic alkenes.
Innovation Solution
A mixed metal oxide support with less than 50 wt.% carbonate, incorporating Column 1 metals, Column 3 or 4 metals, or lanthanide metals, is used to stabilize the alkali metal catalyst, enhancing selectivity and durability for producing branched aliphatic alkenes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If alkali metal on carbonate support catalysts are used for dimerization, then high selectivity for branched alkenes is achieved, but long induction time (10 hours or more) occurs
Solution Approach 1:
The patent changes the chemical composition parameters of the support material by incorporating mixed metal oxides (alumina, silica, magnesia, titania, zirconia, hafnia) in specific ratios with alkali metal carbonates. This compositional modification enables the catalyst to achieve high selectivity without requiring long induction periods, directly resolving the contradiction between selectivity and time.
2Manufacturing precision
If alkali metal on carbonate support catalysts are used, then high selectivity is achieved, but structural degradation occurs during use
Solution Approach 1:
The patent creates a composite catalyst system where alkali metal carbonate is supported on a mixed metal oxide framework. The multiple metal oxides work synergistically to provide both the catalytic activity for high selectivity and the structural stability to prevent degradation during operation, resolving the contradiction between selectivity and stability.
3Productivity
If metallic potassium is used as catalyst, then dimerization activity is achieved, but the nature of supporting material is strongly limited
Solution Approach 1:
The patent develops a universal catalyst system where alkali metal (not limited to potassium) can be supported on multiple types of metal oxide supports. The mixed metal oxide framework provides a versatile platform that accommodates different alkali metals and maintains catalytic activity, thereby expanding the range of compatible supporting materials while preserving dimerization 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
The solution significantly reduces induction time and prevents structural collapse, achieving high selectivity for branched alkenes like 4-methyl-1-pentene, with selectivity rates exceeding 90% after 6 hours.
Implementation Method 1
A discovery has been made that addresses at least some of the problems associated with catalysts used for dimerization of olefins to produce hydrocarbons having a higher carbon number
Implementation Method 2
reacting a feed stream that includes aliphatic alpha olefins (e.g., olefins having a carbon number of 1 to 5, 2 to 4, or about 3) with a supported alkali metal or alkali metal composite catalyst to produce the branched aliphatic alkene
Data Source
AI summary
Catalysts for producing a branched aliphatic alkene are described. The catalyst can include a catalytic alkali metal or alkali metal composite on a mixed metal oxide support that includes a Column 1 metal and at least one of a Column 3 metal, a Column 4 metal or a lanthanide. The catalyst can have less than 50 wt. % of a metal carbonate. Methods of producing branched aliphatic alkenes by contacting the catalyst of the present invention with an aliphatic alpha olefin are also described.