PCP Ligand Chromium Catalyst for Stable 1-Octene Production
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Solution Overview
Problem
Conventional methods for producing 1-octene through ethylene tetramerization using chromium-based catalysts with PNP backbone structure ligands face challenges in maintaining high selectivity and reaction activity over time, with limited understanding of ligand structures and rapid decrease in reaction rate.
Innovation Solution
A chromium-based catalyst system incorporating a P—C—C—P backbone structure ligand, represented by Formula 1, is used for ethylene tetramerization, which maintains high selectivity and activity by avoiding nitrogen in the backbone and optimizing hydrocarbyl group substituents, preventing a decrease in reaction rate over time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional PNP backbone structure ligands are used in chromium-based catalysts, then initial 1-octene selectivity can be achieved, but reaction rate decreases rapidly over time
Solution Approach 1:
The invention changes the fundamental parameter of the ligand backbone structure from PNP (phosphorus-nitrogen-phosphorus) to PCP (phosphorus-carbon-phosphorus). This structural parameter change transforms the catalyst's performance characteristics, maintaining high 1-octene selectivity while preventing the rapid deactivation observed with PNP ligands. The carbon-based backbone provides greater stability and sustained catalytic activity throughout the reaction period.
Solution Approach 2:
The invention creates a composite catalyst system combining chromium metal center with specifically designed PCP ligands featuring hydrocarbyl groups. This composite structure integrates the catalytic activity of chromium with the stability and selectivity-enhancing properties of the PCP ligand framework, achieving both high initial selectivity and sustained reaction rate over time.
2Quantity of substance
If chromium-based catalysts with PNP ligands are used for ethylene tetramerization, then 1-octene production is achieved, but catalyst activity is not maintained constant
Solution Approach 1:
The invention modifies the ligand backbone composition parameter by replacing nitrogen atoms with carbon atoms in the PNP structure, creating a PCP backbone. This parameter change fundamentally alters the catalyst's stability profile, allowing it to maintain constant activity throughout the reaction while continuing to produce high quantities of 1-octene.
Solution Approach 2:
The invention effectively replaces the unstable, short-lived PNP ligand system with a more stable PCP ligand system that acts as a durable, long-lasting catalyst component. This substitution eliminates the need for frequent catalyst replenishment while maintaining high productivity.
3Reliability
If conventional ligand structures are used, then some 1-octene selectivity is achieved, but the understanding of ligand structure-performance relationship is limited
Solution Approach 1:
The invention systematically varies parameters of the PCP ligand structure, specifically the hydrocarbyl groups attached to the phosphorus atoms, to establish structure-performance relationships. By changing these substituent parameters while maintaining the PCP backbone, the invention provides comprehensive information about how ligand structure influences catalyst performance, filling the knowledge gap left by conventional PNP ligand studies.
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 stability for producing 1-octene, maintaining catalytic activity and ensuring a consistent yield of 1-octene, outperforming conventional PNP ligand systems in terms of reaction time stability.
Implementation Method 1
research on methods of producing 1-octene by selectively tetramerizing ethylene through transition metal catalysis has been conducted
Data Source
AI summary
Disclosed herein is a method of preparing 1-octene at high activity and high selectivity while stably maintaining reaction activity by tetramerizing ethylene using a chromium-based catalyst system comprising a transition metal or a transition metal precursor, a cocatalyst, and a P—C—C—P backbone structure ligand represented by (R1)(R2)P—(R5)CHCH(R6)—P(R3)(R4).