Chromium Catalyst Oligomerization with Oxygen Additive
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Solution Overview
Problem
Current olefin oligomerization processes face challenges with high costs due to expensive aluminium-containing catalyst activators, low reaction rates at low aluminium concentrations, and excessive polymer formation leading to plant shut-downs and reduced economic performance.
Innovation Solution
Incorporating a non-metal oxygen-containing additive, such as dioxygen, in specific ratios with a chromium-based oligomerization catalyst system to enhance catalyst activity, productivity, and reduce polymer formation, while maintaining economic viability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If aluminium-containing compounds are used as catalyst activators, then catalyst activity is improved, but process cost increases significantly
Solution Approach 1:
The patent replaces expensive aluminium-containing activators with cheaper organic salts (methyl lithium, methyl magnesium bromide) that can be used at lower costs. The invention demonstrates that these alternative activators achieve sufficient catalyst activity without the high costs associated with aluminium compounds, directly addressing the contradiction between productivity and cost.
Solution Approach 2:
The patent changes the chemical composition parameter of the activator from aluminium-containing compounds to organic salts. By modifying the activator type and adjusting concentrations (e.g., using 0.01-10 mol% of chromium catalyst with specific organic salt activators), the process achieves cost reduction while maintaining acceptable catalyst activity and productivity.
2Quantity of substance
If aluminium concentration is reduced to lower cost, then process cost decreases, but reaction rate decreases
Solution Approach 1:
The patent changes the activator chemistry from aluminium-based to organic salt-based systems, which allows operating at lower metal concentrations while maintaining reaction rate. The invention shows that organic salt activators can compensate for reduced aluminium content, preserving reaction speed at lower costs.
Solution Approach 2:
The patent introduces organic salt compounds as intermediary activators that mediate between the chromium catalyst and the olefin substrate. These intermediaries (methyl lithium, methyl magnesium bromide) transfer alkyl groups to the chromium catalyst, maintaining active species formation even at reduced aluminium concentrations, thus preserving reaction rate while lowering cost.
3Productivity
If catalyst activity is increased to improve productivity, then space-time yield improves, but polymer formation increases causing plant shut-downs
Solution Approach 1:
The patent changes multiple parameters including activator type (from aluminium to organic salts), chromium catalyst concentration (0.01-10 mol%), and additive composition to optimize the balance between activity and polymer formation. The invention demonstrates that these parameter changes enable high space-time yields while suppressing polymer formation to acceptable levels.
Solution Approach 2:
The patent converts the previously harmful effect of oxygen (which was removed from the system) into a beneficial additive. By introducing oxygen-containing additives (ketones, aldehydes, carboxylic acids) at controlled concentrations, the invention suppresses polymer formation and improves catalyst stability, turning a harmful factor into a beneficial control mechanism.
4Duration of action of stationary object
If polymer formation is reduced to minimize fouling, then plant run time increases, but catalyst activity may be compromised
Solution Approach 1:
The patent converts oxygen from a harmful impurity into a beneficial additive that suppresses polymer formation. By controlling oxygen-containing additive concentration, the system extends plant run time between shut-downs while maintaining catalyst activity through the improved stability and reduced fouling.
Solution Approach 2:
The patent adjusts multiple parameters including chromium catalyst concentration (0.01-10 mol%), activator type and concentration, and oxygen-containing additive levels to optimize the trade-off between activity and run time. The invention shows that these parameter optimizations enable extended operation without significant activity loss.
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 increased catalyst activity and productivity, reduces polymer formation, and optimizes economic performance by using a non-metal oxygen-containing additive within a narrow concentration range, balancing activity and productivity while minimizing polymer formation.
Implementation Method 1
a process for producing an oligomeric product by the oligomerisation of at least one olefinic compound in the presence of an activated oligomerisation catalyst
Implementation Method 2
Incorporating a non-metal oxygen-containing additive, such as dioxygen, in specific ratios with a chromium-based oligomerization catalyst system to enhance catalyst activity
Data Source
AI summary
A process for oligomerisation of an olefinic compound for producing an oligomeric product is carried out in the presence of an activated catalyst, a non-metal oxygen containing additive and optionally a zinc compound. The oligomerisation catalyst is an activated catalyst, which is provided by combining a source of chromium, a ligating compound, and a catalyst activator or combination of catalyst activators. The non-metal oxygen containing additive is present in an amount such that the ratio of the molar amount of the non-metal oxygen containing additive to the molar amount of chromium in the source of chromium per 106 g/g Cr productivity is between 0.01 and 400.