Chromium Catalyst System for Olefin Trimerization and Tetramerization
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Solution Overview
Problem
Existing catalyst systems for olefin oligomerization are limited to only trimerization and lack the capability to selectively tetramerize olefins, requiring complex solvent removal processes and resulting in reduced thermal stability and selectivity.
Innovation Solution
A catalyst system comprising a ligand compound, a chromium compound, and a metal alkyl compound, with a specific molar ratio, that enables both trimerization and tetramerization of olefins in a homogeneous liquid phase reaction, using an inert solvent and controlling the electronic and steric environment around the transition metal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a catalyst system is prepared in an unsaturated hydrocarbon solvent to maintain thermal stability and selectivity, then catalyst activity and selectivity are improved, but additional solvent removal processes and filtering steps are required
Solution Approach 1:
The patent changes the solvent parameter from unsaturated hydrocarbon to saturated hydrocarbon, which fundamentally alters the catalyst preparation environment. This parameter change allows the catalyst to maintain its active species formation while eliminating the need for subsequent solvent removal and filtering processes, thus resolving the contradiction between catalyst selectivity and process complexity
Solution Approach 2:
The invention extracts and removes the problematic unsaturated hydrocarbon solvent from the catalyst preparation process by replacing it with a saturated hydrocarbon solvent. This extraction eliminates the harmful effects of unsaturated solvents (black precipitate formation, need for filtering) while preserving the desired catalyst performance
2Ease of manufacture
If the catalyst system is prepared in a saturated hydrocarbon solvent to simplify the process, then the solvent removal process is eliminated, but the thermal stability of the catalyst is degraded and selectivity is reduced
Solution Approach 1:
The patent optimizes specific parameters of the saturated hydrocarbon solvent (such as molecular structure, boiling point, and chemical inertness) to ensure they are compatible with catalyst active species formation. This refined parameter adjustment allows the saturated solvent to provide both process simplicity and catalyst stability simultaneously
3Productivity
If existing catalyst systems are used for olefin oligomerization, then trimerization can be achieved, but tetramerization capability is lost and by-product formation increases
Solution Approach 1:
The patent creates a composite catalyst system combining chromium compound, aluminum alkyl, and pyrrole ligand in specific ratios within a saturated hydrocarbon solvent. This composite formulation synergistically enhances both trimerization and tetramerization capabilities while suppressing by-product formation through the coordinated interaction of all components
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 system achieves high selectivity and activity in producing 1-hexene and 1-octene with improved thermal stability and reduced by-product formation, eliminating the need for solvent removal processes.
Implementation Method 1
a catalyst system comprising a ligand compound, a chromium compound, and a metal alkyl compound, with a specific molar ratio, that enables both trimerization and tetramerization of olefins
Data Source
AI summary
Disclosed are a novel catalyst system which is a catalyst system for selectively oligomerizing olefin including ethylene and may trimerize and tetramerize olefin, different from the catalyst system for olefin oligomerization reported until now, and a method for preparing an olefin oligomer using same. The present invention provides a catalyst system for olefin oligomerization, including a ligand compound represented by Formula 1 or 2; a chromium compound; and a metal alkyl compound, and a method for preparing an olefin oligomer using same.