Catalyst Components 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 due to their potential medical issues, necessitating the search for alternative classes of internal donors to achieve higher crystallinity and isotacticity in polymerization.
Innovation Solution
A catalyst component comprising Mg, Ti, halogen, and an electron donor compound of specific formula (I) with preferred structures and substituents, supported on a Mg dihalide, which replaces traditional phthalates to enhance polymerization performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If phthalates are used as internal donors in Ziegler-Natta catalysts, then good polymerization performance (activity, isotacticity, xylene insolubility) is achieved, but health risks arise due to medical issues associated with phthalate use
Solution Approach 1:
The patent changes the chemical structure parameter of the internal donor from phthalate esters to cyclic carboxylate esters with specific molecular formulas (C12H14O4, C14H18O4, C16H22O4). This structural parameter change maintains the catalytic functionality while eliminating the harmful health effects associated with phthalates, achieving both good polymerization performance and health safety
Solution Approach 2:
The patent replaces the problematic phthalate class of compounds with alternative cyclic carboxylate ester compounds that serve the same functional purpose but without the harmful side effects. These alternative donors are designed to be effective at the required concentrations (0.1-5.0 wt%) while being safe for use
2Object-affected harmful factors
If alternative internal donors are sought to replace phthalates, then health safety is improved, but achieving high crystallinity and isotacticity becomes more difficult
Solution Approach 1:
The patent optimizes specific parameters of the cyclic carboxylate ester structure (molecular formula, ring size, substituent groups at positions 2 and 5) to achieve the desired isotacticity. The systematic variation of these structural parameters allows tuning of the catalyst's stereoselectivity while maintaining health safety
Solution Approach 2:
The patent creates a composite catalyst system combining MgCl2 support, TiCl4, and the specifically designed cyclic carboxylate ester internal donor. This composite structure synergistically achieves both health safety (by excluding phthalates) and high isotacticity (through the optimized donor structure and its interaction with the support and titanium species)
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 new catalyst component achieves high isotacticity and crystallinity in propylene polymerization while avoiding health risks associated with phthalates, maintaining good activity and xylene insolubility, with preferred electron donor compounds like 1,2-diphenylethene-1,2-diyl bis(2,2-dimethylpropanoate) and 1,2-diphenylethene-1,2-diyl bis(4-chlorobenzoate, providing effective support for Ti atoms on a Mg dihalide.
Implementation Method 1
A catalyst component for the polymerization of olefins comprising Mg, Ti, halogen and an electron donor of formula (I)
Data Source
AI summary
A solid catalyst component which exhibits high activity and stereo specificity polymerization of olefins comprising Mg, Ti and an electron donor of formula (I) where R and R1 are selected from C1-C20 hydrocarbon groups C6-C14 aryl or alkylaryl groups hydrocarbon groups, optionally containing a heteroatom selected from halogen, P, S, N,O; R2 to R11 groups, equal to or different from each other, are hydrogen, halogen or C1-C15 hydrocarbon groups which can be optionally fused together to form one or more cycles with the proviso that R6 and R11 cannot join together to form a phenyl ring.