Chromium Catalyst System for Olefin Oligomerization
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Solution Overview
Problem
Current methods for oligomerization of olefins to produce linear α-olefins, such as hexene-1, face challenges with low isomeric purity, high energy consumption, and the need for expensive catalyst components, leading to inefficient production and increased costs.
Innovation Solution
A catalyst system comprising a chromium source, a nitrogen-containing ligand, alkylaluminum, and a zinc compound, activated through heating and SHF irradiation or aging, is used for oligomerization, enhancing the selectivity and purity of the target linear α-olefin to 99.9%.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If rectification is used for purification of α-olefins, then isomeric purity is improved, but energy consumption and capital expenditures increase significantly
Solution Approach 1:
The patent changes the chemical composition parameters of the catalyst system by introducing a zinc compound (specifically diethylzinc) in combination with chromium source and nitrogen-containing ligands. This compositional parameter change transforms the catalyst's selectivity properties, enabling high isomeric purity (99.5-99.9%) to be achieved through catalysis rather than energy-intensive rectification processes.
2Manufacturing precision
If expensive components like P-N-P ligands and MAO are used in oligomerization catalyst systems, then selectivity to target α-olefin is improved, but manufacturing cost increases
Solution Approach 1:
The patent replaces expensive, complex ligand systems (P-N-P ligands, MAO) with a simpler, more economical catalyst composition based on chromium source, nitrogen-containing ligands, and zinc compound. This substitution uses cheaper, more accessible materials that achieve comparable or superior selectivity, eliminating the need for costly components while maintaining high α-olefin production efficiency.
Solution Approach 2:
The patent fundamentally changes the catalyst system's compositional parameters by incorporating a zinc compound (diethylzinc) as a key component. This parameter change creates a new catalyst class that achieves high selectivity without requiring expensive P-N-P ligands or modified methylalumoxane, thereby reducing manufacturing costs while maintaining or improving selectivity to target α-olefins.
3Manufacturing precision
If internal olefins are isomerized using heterogeneous catalyst followed by rectification, then isomeric purity is improved, but process complexity and labor intensity increase
Solution Approach 1:
The patent extracts the isomerization function from a separate preprocessing step and integrates it directly into the oligomerization reaction itself. By using a zinc-containing chromium catalyst system, the catalyst selectively produces terminal α-olefins while minimizing internal olefin formation during the oligomerization process. This eliminates the need for subsequent isomerization and rectification steps, simplifying the overall process while achieving high isomeric purity.
4Manufacturing precision
If additional reagents are used for isolation of isomerically pure α-olefin, then isomeric purity is improved, but process cost and time consumption increase
Solution Approach 1:
The patent enables the catalyst system to self-selectively produce high-purity α-olefins through its inherent chemical selectivity. The zinc compound-chromium catalyst system naturally favors the formation of terminal α-olefins over internal isomers during oligomerization, eliminating the need for additional reagents or extensive purification steps. The process achieves high isomeric purity through the catalyst's own properties rather than through auxiliary isolation procedures, saving both time and resources.
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 method significantly increases the isomeric purity of α-olefins, reducing losses during recycling and improving the efficiency and cost-effectiveness of polyolefin production by minimizing by-products and energy consumption.
Implementation Method 1
alkylaluminum or a mixture of the alkylaluminum and the zinc compound is activated by heating and SHF irradiation (microwave irradiation) or by heating separate components, followed by holding (aging) the prepared catalyst system for a certain period of time
Implementation Method 2
alkylaluminum or a mixture of the alkylaluminum and the zinc compound is activated by heating and SHF irradiation (microwave irradiation)
Implementation Method 3
followed by holding (aging) the prepared catalyst system for a certain period of time
Implementation Method 4
catalyst system comprising a chromium source, a nitrogen-containing ligand, alkylaluminum, and a zinc compound
Data Source
AI summary
The invention relates to the field of oligomerization of olefins to produce linear α-olefins, in particular hexene-1, with the use of a catalyst system. The catalyst system comprises a chromium source compound, a nitrogen-containing ligand, alkylaluminum, and a zinc compound, wherein catalyst system is activated during its preparation by 1) heating some and SHF irradiation (microwave irradiation) of alkylaluminum or a mixture of the alkylaluminum and the zinc compound, or by 2) heating alkylaluminum or a mixture of the alkylaluminum and the zinc compound, followed by holding (aging) the prepared catalyst system for a certain period of time.