Catalyst Component with Carbamate-Ester Donor for Olefin Polymerization
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Solution Overview
Problem
The use of phthalates as internal donors in Ziegler-Natta catalysts for propylene polymerization raises health concerns and results in catalysts with low activity and stereospecificity, necessitating the search for alternative electron donor compounds.
Innovation Solution
A catalyst component comprising Mg, Ti, and an electron donor compound with both carbamate and ester functions, specifically structured with certain hydrocarbon groups and bridging groups, is developed to enhance activity and stereospecificity in olefin polymerization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If phthalates are used as internal donors in Ziegler-Natta catalysts, then the catalyst system shows good activity and stereospecificity, but health concerns arise due to medical issues associated with phthalate use
Solution Approach 1:
The invention changes the chemical structure parameter of the internal donor compound from phthalate esters to compounds containing carbamate and ester functions. This structural parameter change maintains the catalytic performance (stereospecificity and activity) while eliminating the harmful health effects associated with phthalates, as demonstrated by the superior results of compounds of formula (I) compared to conventional phthalates
Solution Approach 2:
The invention replaces the problematic phthalate compounds with alternative compounds (carbamate-ester compounds of formula (I)) that serve the same functional purpose but without the harmful properties. These alternative compounds are designed to be effective at the required concentrations without the long-term health accumulation issues of phthalates
2Object-affected harmful factors
If amino acid derivatives with carbamate groups and free ester function are used as internal donors, then health safety is improved, but catalyst activity and stereospecificity become very low
Solution Approach 1:
The invention optimizes the structural parameters of the carbamate-ester compounds by specifying particular arrangements of R1 groups, bridging groups A, and the relative positions of carbamate and ester functions. This structural optimization distinguishes the effective compounds of formula (I) from the ineffective amino acid derivatives, achieving both health safety and high stereosspecificity
Solution Approach 2:
The invention creates a composite functional structure combining carbamate and ester groups within a specific molecular framework (formula (I)). This composite structure integrates the beneficial properties of both functional groups while avoiding the deficiencies of using either group alone or in the amino acid derivative configuration
3Reliability
If conventional Ziegler-Natta catalyst systems with phthalates and alkoxysilanes are used, then good polymerization activity and isotacticity are achieved, but the system complexity increases due to requiring multiple donor compounds
Solution Approach 1:
The invention merges the functions of internal and external donors into a single compound type (carbamate-ester of formula (I)). The compound can serve as an internal donor on the MgCl2 support, and the same or related compounds can function as external donors, thereby simplifying the overall catalyst system while maintaining or improving isotacticity
Solution Approach 2:
The carbamate-ester compounds of formula (I) exhibit multi-functionality, serving effectively as internal donors in the Ziegler-Natta catalyst system. The same structural type can also function as external donors, providing universal applicability that reduces the need for multiple specialized compounds and simplifies the catalyst formulation
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 component achieves an excellent balance of activity and stereospecificity, overcoming the limitations of phthalate-based systems and providing a safer, more effective alternative for propylene polymerization.
Implementation Method 1
catalyst component for the polymerization of olefins
Data Source
AI summary
A solid catalyst component for the polymerization of olefins comprising Mg, Ti and an electron donor of formula (I), where R1 is selected from C1-C15 hydrocarbon groups, R2 groups, equal to or different from each other, are hydrogen or R1 groups which can be fused together to form one or more cycles and A is a bivalent bridging group. The said catalyst components exhibit high activity and stereo specificity in the polymerization of olefins.