Monoester Catalyst Composition for Polyolefin Yield and Isotacticity
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Solution Overview
Problem
Current catalyst systems for olefin polymerization, such as Ziegler-Natta catalysts, face limitations in achieving high activity, controlled stereochemistry, high isotacticity, and broader molecular weight distribution while maintaining high yield and low amorphous atactic polymer content, which is essential for various polymer applications.
Innovation Solution
A catalyst composition comprising a monoester and an internal electron donor represented by a specific formula, which includes a magnesium-containing support, a halogen-containing titanium compound, and an additional internal electron donor, allowing for the production of polyolefins with broader molecular weight distribution, higher yield, and improved isotacticity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional Ziegler-Natta catalyst systems are used, then polymerization activity is achieved, but the molecular weight distribution remains narrow and yield is limited
Solution Approach 1:
The patent applies parameter changes by modifying the chemical composition parameters of the catalyst system - specifically using a magnesium compound with controlled morphology and composition (Mg(OAlk)xCl2-x where x is 0.5-1.5), combining it with titanium tetrachloride and dibutyl phthalate in specific ratios. This parameter optimization resolves the contradiction by achieving both high polymer yield (3-10 times higher than conventional catalysts) and broad molecular weight distribution (Mw/Mn ratio of 6-10) simultaneously.
2Manufacturing precision
If catalyst components are varied to improve isotacticity and activity, then polymer quality improves, but the complexity of catalyst preparation increases
Solution Approach 1:
The patent employs composite materials by creating a composite catalyst system consisting of a magnesium compound (Mg(OAlk)xCl2-x) with specific morphology, titanium tetrachloride (TiCl4), and dibutyl phthalate (DBP). This composite approach achieves high isotacticity (95-98% isotactic polypropylene) and high activity while managing preparation complexity through a standardized multi-step process that has become industrially established.
3Productivity
If conventional catalysts are used for high activity, then production efficiency increases, but amorphous atactic polymer content increases which reduces product quality
Solution Approach 1:
The patent uses dibutyl phthalate as an intermediary substance that mediates between the magnesium compound and titanium tetrachloride during catalyst preparation. This intermediary agent facilitates the formation of a specific catalyst structure that achieves high activity (producing 3-10 times more polymer than conventional catalysts) while simultaneously suppressing the formation of amorphous atactic polymer, delivering high isotacticity (95-98%) product.
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 composition achieves polyolefins with broader molecular weight distribution, higher yield, and improved isotacticity, reducing the amount of low molecular weight polymers and amorphous atactic content, making it suitable for diverse applications like thermoforming, pipes, and films, while being non-toxic for use in food and medical industries.
Implementation Method 1
a compound Mg(OAlk) x Cl y of certain morphology is prepared, and subsequently this solid Mg-compound is contacted with titanium tetrachloride, and an internal electron-donating compound, which is dibutyl phthalate
Implementation Method 2
catalyst composition for polymerization of olefins comprising a monoester and an internal donor being a compound represented by formula (I)
Data Source
AI summary
The present invention relates to a catalyst composition comprising a monoester, the compound represented by formula (I) as an internal electron donor, and optionally an additional internal electron donor selected from a group consisting of diesters and diethers, Formula (I) wherein: R1, R2, R3, R4, R5 and R6 are the same or different and are independently selected from the group consisting of hydrogen, straight, branched and cyclic alkyl having at most 20 carbon atoms and aromatic substituted and unsubstituted hydrocarbyl having 6 to 20 carbon atoms; R7 is selected from the group consisting of straight, branched and cyclic alkyl having at most 20 carbon atoms and aromatic substituted and unsubstituted hydrocarbyl having 6 to 20 carbon atoms; and R8 is selected from the group consisting of aromatic substituted and unsubstituted hydrocarbyl having 6 to 20 carbon atoms. The present invention also relates to a process for preparing said polymerization catalyst composition and to a polymerization catalyst system comprising said catalyst composition, a co- catalyst and optionally an external electron donor. Furthermore, the present invention relates to use of said catalyst composition for polymerization of olefins.