UHF-Activated Chromium Catalyst for Low-Pressure Olefin Trimerization
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Solution Overview
Problem
Existing olefin trimerization and oligomerization catalyst systems require high pressure and result in significant by-product formation, leading to reduced selectivity and increased capital expenditures.
Innovation Solution
A catalyst system is prepared using a chromium source, a nitrogen-containing ligand, and alkylaluminum, with the alkylaluminum component being exposed to UHF radiation to enhance activity and selectivity at lower pressures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional chromium-based catalyst systems are used for olefin trimerization, then catalytic activity can be achieved, but high pressure is required and by-products are formed reducing selectivity
Solution Approach 1:
The patent modifies the chemical parameters of the catalyst system by introducing specific nitrogen-containing ligands (pyrrole derivatives with electron-donating groups) and controlling the Cr:Al ratio and ligand:Cr ratio. These parameter changes enable the catalyst to achieve high selectivity (96-99% hexene-1) at lower ethylene pressures (12-37.4 bar) compared to conventional systems
Solution Approach 2:
The patent creates a composite catalyst system combining chromium salt, nitrogen-containing pyrrole ligand, and alkylaluminum in specific ratios. This composite structure with multiple components working synergistically improves both selectivity and activity while reducing the required operating pressure
2Productivity
If conventional chromium-based catalyst systems are used for olefin trimerization, then the reaction can proceed, but significant by-products are formed leading to reduced target product selectivity
Solution Approach 1:
The patent introduces nitrogen-containing ligands with specific local electronic properties (electron-donating groups at positions 2 and 5 of the pyrrole ring) that create a localized electronic environment around the chromium center. This local modification enhances the catalyst's ability to selectively bind and transform ethylene molecules while minimizing unwanted side reactions that produce by-products
Solution Approach 2:
The patent converts the potential harm of by-product formation into benefit by using the alkylaluminum component not only as an activator but also as a selective promoter that suppresses oligomerization side reactions. The specific Cr:Al ratio control ensures that aluminum species enhance the desired trimerization pathway while minimizing decene and other by-product formation
3Manufacturing precision
If ethylene pressure is reduced to decrease capital expenditures, then operating costs decrease, but the rate of reaction and catalyst productivity drop to low levels
Solution Approach 1:
The patent optimizes multiple parameters simultaneously: the Cr:Al ratio (1:15), ligand:Cr ratio (3:1), and ethylene pressure (12-37.4 bar). These coordinated parameter changes create a catalyst system that maintains high productivity (66,400 g/(g Cr·hr)) even at reduced pressures, resolving the trade-off between pressure reduction and activity maintenance
Solution Approach 2:
The patent performs preliminary activation of the chromium catalyst by alkylaluminum before the actual trimerization reaction. This pre-activation step creates highly active chromium species that can drive the reaction at lower pressures. The catalyst system is prepared in advance with optimal composition to ensure high activity is achieved when the reaction commences at reduced pressure
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 process achieves higher activity and selectivity for olefin trimerization and oligomerization at lower pressures, reducing capital expenditures and by-product formation.
Implementation Method 1
alkylaluminum is exposed to UHF radiation
Data Source
AI summary
The invention relates to the field of producing polymers and copolymers of olefin oligomers produced by a trimerization reaction of olefin monomers. There is disclosed a process which comprises producing olefin oligomers with the aid of a trimerization catalyst system prepared using UHF irradiation for activating individual components of the trimerization catalyst system. The use of the trimerization catalyst system thus improved and having increased activity provides for increased effectiveness in the production of olefin oligomers from ethylene or other olefin monomers, inter alia, at a low pressure of ethylene. The olefin oligomers thus produced are then polymerized or copolymerized using processes known in the art. The technical effect consists in increasing the effectiveness of the production of olefin oligomers which are then used in a polymerization or copolymerization reaction.