Meta-Substituted Fluorophenylborate Activators for Olefin Polymerization
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Solution Overview
Problem
Current catalyst systems for olefin polymerization, such as metallocene and Ziegler-Natta systems, often rely on activators like alumoxanes and aluminum alkyls, but there is a lack of attention to substitution at the meta positions of fluorophenylborates, which could potentially enhance solubility and molecular weight of polymers.
Innovation Solution
The development of fluorophenylborates with specific meta-position substitutions, represented by the formula Ct+[B-(ArfRn)4]-, where Ct+ is a cation capable of extracting an alkyl group or breaking a carbon-metal bond, and Arf is a fluorophenyl group with R being fluorophenyl or fluoronaphthyl groups, to create a novel activator for olefin polymerization catalyst systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If fluorine atoms in fluorophenylborates are substituted with bulky groups at the para-position, then solubility in aliphatic solvents and molecular weight of polymers are improved, but substitution at the meta positions has been neglected and may offer further improvements
Solution Approach 1:
The patent applies local quality by substituting fluorine atoms at specific meta positions (3 and 5) of the fluorophenylborate structure with bulky groups. This localized substitution approach improves solubility in aliphatic solvents while maintaining the overall molecular architecture. The meta-position substitution complements the previously explored para-position substitutions, providing enhanced local properties without completely redesigning the molecule.
Solution Approach 2:
The patent changes the substitution parameters by exploring meta-position substitution patterns (3,5-di-tert-butyl-4-fluorophenyl groups) as an alternative to para-position substitution. This parameter change in the substitution pattern leads to improved solubility characteristics and polymer molecular weights, demonstrating how modifying substitution parameters can resolve the contradiction between solubility and structural complexity.
2Productivity
If fluorophenylborates with meta-position substitutions are used as activators, then the rate of olefin polymerization and polymer properties are enhanced, but the synthesis and characterization of these novel compounds require additional effort
Solution Approach 1:
The patent employs preliminary action by pre-synthesizing the novel 3,5-di-tert-butyl-4-fluorophenylborate compounds before using them as activators. The synthesis pathway is established in advance, showing that the additional synthesis effort is a one-time investment that enables subsequent polymerization reactions to proceed at enhanced rates. The preliminary preparation of these specialized activators resolves the contradiction by enabling high productivity in the actual polymerization process.
Solution Approach 2:
The patent effectively uses disposable activator molecules with specific meta-substituted fluorophenylborate structures. These activators are designed to be used in catalytic amounts and then consumed or deactivated after facilitating the polymerization reaction. The enhanced polymerization rate achieved with these specialized activators justifies the additional synthesis effort, as the activators enable high productivity in a single-use capacity.
3Reliability
If traditional activators like alumoxanes and aluminum alkyls are used, then the polymerization process is well-established, but the molecular weight and other polymer properties are limited compared to fluorophenylborates with meta-position substitutions
Solution Approach 1:
The patent creates a composite activator system by combining the stable borate anion framework with bulky meta-substituted aryl groups (3,5-di-tert-butyl-4-fluorophenyl). This composite structure integrates the reliability of the borate core with the solubility and steric properties of the bulky substituents. The resulting activator maintains process stability while enabling higher molecular weights in the resulting polymers, effectively resolving the contradiction between reliability and productivity.
Solution Approach 2:
The patent changes the chemical parameters of the activator by transitioning from traditional alumoxanes and aluminum alkyls to meta-substituted fluorophenylborates. This parameter change in the activator chemistry fundamentally alters the polymerization outcome, enabling higher molecular weights and improved polymer properties while maintaining adequate process stability. The parameter change resolves the contradiction by moving to a different chemical regime that offers superior performance.
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
This approach enhances the rate of olefin polymerization and affects molecular weight, degree of branching, and comonomer content of the resultant polymers, offering improved properties compared to traditional activators.
Implementation Method 1
Ionizing activators generally include a cation capable of abstracting an alkyl group, or breaking a carbon-metal bond, from the organometallic primary catalyst species
Data Source
AI summary
A fluorophenylborate useful as an activator for an olefin polymerization catalyst is represented by the formula: Ct+ [B-(ArfRn)4]- where Ct+ is a cation capable of extracting an alkyl group from, or breaking a carbon-metal bond of, an organo metallic compound; Arf is a fluorophenyl group; n is 1 or 2; and each R is independently selected from a fluorophenyl group and a fluoronaphthyl group, provided that when n=l, each R group is connected at the 3- position relative the connection between the associated Arf group and the boron atom and, when n=2; the R groups are connected at the 3-position and the 5- position respectively relative the connection between the associated Arf group and the boron atom.