Ethylene Oligomerization with Chain Transfer Agents
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current ethylene oligomerization processes for producing normal alpha olefins often result in significant polymer formation, which reduces reactor operation time, reliability, and complicates product isolation, necessitating the development of novel and improved processes.
Innovation Solution
A process involving the contact of ethylene with a catalyst system comprising a zirconium compound, a hydrocarbylmetal compound, and a chain transfer agent, such as a silyl hydride or hydrogen, to produce an oligomer product with a Schulz-Flory K value between 0.4 and 0.8, minimizing polymer formation and improving reaction efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional ethylene oligomerization processes are used, then normal alpha olefins are produced, but significant polymer formation occurs which reduces reactor operation time and complicates product isolation
Solution Approach 1:
The patent modifies the chemical parameters of the oligomerization process by introducing specific chain transfer agents (silanes, phosphines, sulfur compounds) and controlling their concentrations. These parameter changes alter the reaction kinetics to favor oligomer formation over polymerization, thereby extending reactor operation time while maintaining productivity
Solution Approach 2:
Chain transfer agents are introduced as intermediary substances that mediate between the catalyst and ethylene monomer. These intermediaries control the chain growth process by transferring active centers, preventing uncontrolled polymerization while enabling selective oligomer formation, thus improving reactor reliability
2Productivity
If conventional ethylene oligomerization processes are used, then normal alpha olefins are produced, but significant polymer formation complicates product isolation
Solution Approach 1:
By adjusting process parameters including chain transfer agent selection and concentration, the patent produces oligomers with specific molecular weight distributions and reduced polymer content. This parameter optimization simplifies downstream separation and purification operations, making product isolation easier while maintaining high productivity
3Reliability
If chain transfer agents are used to reduce polymer formation, then reactor operation time is extended, but the catalyst system complexity increases
Solution Approach 1:
The patent employs chain transfer agents that serve multiple functions simultaneously: they control chain growth to extend reactor operation time, regulate oligomer molecular weight distribution, and maintain catalyst activity. This multi-functionality reduces the need for additional process steps or components, thereby limiting the increase in system complexity
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 effectively reduces polymer formation, extending reactor operation time, enhancing reliability, and simplifying product isolation by producing oligomer products with lower molecular weight and reduced polymer content.
Implementation Method 1
a catalytic reaction involving various types of catalysts and/or catalyst systems
Implementation Method 2
contacting i) ethylene, ii) a catalyst system comprising 1) a zirconium compound... and 2) a hydrocarbylmetal compound, iii) a chain transfer agent
Data Source
AI summary
Process for producing alpha olefins comprising contacting ethylene, a zirconium based catalyst system comprising, a hydrocarbylmetal compound, a chain transfer agent, and optionally an organic reaction medium. Chain transfer agents which can be utilized include a) hydrogen, b) a compound comprising a hydrogen silicon bond, a compound having a hydrogen sulfur bond, a compound having a hydrogen phosphorus bond, or c) a transition metal compound chain transfer agent.