Continuous Vinylidene Dimer Synthesis via Metallocene Catalysis
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Solution Overview
Problem
Existing processes for producing high-purity vinylidene dimers from terminal olefins result in significant formation of trimers and higher oligomers, requiring additional purification steps and are inefficient in producing large quantities, with limited selectivity towards vinylidene dimers.
Innovation Solution
A continuous oligomerization process using a catalyst system comprising a metallocene compound and alumoxane, with specific feeding rates and conditions, achieves high selectivity towards vinylidene dimers, allowing direct use of the oligomer mixture as high-purity vinylidene dimer without the need for removing trimers and higher oligomers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a batch oligomerization process using bisCpZrCl2 and methylalumoxane is used, then vinylidene dimer selectivity is improved, but significant formation of trimers and higher oligomers occurs requiring additional purification steps
Solution Approach 1:
The patent changes the oligomerization parameters by switching from batch to continuous process operation and adjusting the catalyst system composition (using metallocene compound combined with alumoxane in specific ratios). These parameter changes enable high vinylidene dimer selectivity while minimizing trimer and higher oligomer formation, resolving the contradiction between selectivity and harmful byproduct formation.
Solution Approach 2:
The patent implements a continuous oligomerization process where terminal olefin monomer continuously reacts with the metallocene-alumoxane catalyst system to produce vinylidene dimers. This continuous operation maintains optimal reaction conditions throughout the process, preventing over-oligomerization and reducing trimer/higher oligomer formation while sustaining high dimer selectivity.
2Quantity of substance
If a batch process is used for oligomerization, then vinylidene dimer production is achieved, but production efficiency for large quantities is reduced
Solution Approach 1:
The continuous oligomerization process allows for uninterrupted production of vinylidene dimers at high rates. The continuous flow of terminal olefin monomer through the reactor system with the metallocene-alumoxane catalyst enables sustained high-volume production with consistent quality, dramatically improving productivity compared to batch processes while maintaining high dimer selectivity.
3Manufacturing precision
If additional purification steps are added to remove trimers and higher oligomers, then vinylidene dimer purity is improved, but process complexity increases
Solution Approach 1:
The continuous oligomerization process using the metallocene-alumoxane catalyst system converts the potential harm of oligomer formation into a benefit by selectively producing vinylidene dimers with minimal trimer and higher oligomer formation. The reaction conditions are optimized so that the continuous process inherently suppresses over-oligomerization, turning what would normally require complex purification into a straightforward process where the product is already high-purity.
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 extremely high selectivity towards vinylidene dimers with low selectivity towards trimers and higher oligomers, enabling the direct use of the oligomer mixture as high-purity vinylidene dimer, with high conversion of terminal olefin monomer and consistent composition and quality.
Implementation Method 1
A continuous process for making a vinylidene dimer from a terminal olefin comprises: feeding a monomer stream comprising the terminal olefin into a reactor... feeding a metallocene compound... feeding an alumoxane feed into the reactor... conducting oligomerization reactions in the reactor
Data Source
AI summary
This disclosure relates to a continuous process for making a dimer from a terminal olefin in the presence of a catalyst system comprising a metallocene compound and alumoxane.