Ziegler-Natta Internal Donors for Multimodal Polyethylene Control
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Solution Overview
Problem
Existing Ziegler-Natta catalysts for polyolefin production often rely on harmful substances like phthalates and tetrahydrofuran, and there is a need for internal donors that provide desirable polymer properties such as high molecular weight, narrow molecular weight distribution, and chemical composition distribution while being environmentally sustainable and commercially viable.
Innovation Solution
The use of compounds of formula (I) as internal donors in Ziegler-Natta catalysts, particularly for ethylene (co)polymerization, which include oxygen-containing heterocyclic rings, allows for the production of multimodal polyethylene with desirable molecular weight distribution and chemical composition distribution without compromising catalyst productivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional internal donors (phthalates, tetrahydrofuran) are used in Ziegler-Natta catalysts, then catalyst productivity is maintained, but environmental harm and health risks increase
Solution Approach 1:
The patent replaces conventional harmful internal donors with alternative compounds (cyclic carboxylic acid esters, cyclic carbonates, cyclic carbamates) that are less harmful to the environment. These alternative donors achieve comparable catalyst productivity while eliminating the environmental and health risks associated with phthalates and tetrahydrofuran, effectively substituting harmful substances with safer alternatives that maintain catalytic performance.
Solution Approach 2:
The patent changes the chemical parameters of the internal donor by selecting compounds with specific structural characteristics (cyclic esters, carbonates, carbamates with particular ring sizes and substituents). This parameter change in the donor's chemical structure enables the catalyst to maintain high productivity while reducing environmental harm, as the new donor class provides similar electronic and steric properties without the toxic effects of conventional donors.
2Manufacturing precision
If internal donors are used to control molecular weight distribution, then polymer properties improve, but catalyst composition complexity increases
Solution Approach 1:
The patent utilizes parameter changes in the internal donor's molecular structure (ring size, substituents, functional groups) to precisely control the catalyst's activity and the polymer's molecular weight distribution. By selecting donors with specific parameters within the defined classes, the catalyst composition remains relatively simple while achieving precise control over polymer properties through the electronic and steric effects of the donor.
Solution Approach 2:
The patent applies local quality by introducing specific functional groups and substituents at particular positions within the cyclic donor structures. This localized modification of the donor's structure allows fine-tuning of the catalyst's behavior and the polymer's molecular weight distribution without requiring complex overall catalyst compositions, maintaining simplicity while achieving precision.
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 use of these internal donors results in ethylene (co)polymers with improved molecular weight distribution and chemical composition distribution, maintaining high productivity and avoiding the use of harmful substances, thus meeting environmental and commercial requirements.
Implementation Method 1
The catalysts comprise at least a catalyst component formed from a transition metal compound of Group 4 to 6, a metal compound of Group 1 to 3, and an internal electron donor
Implementation Method 2
Ziegler-Natta (ZN) type polyolefin catalysts are well known in the field of producing polyolefins, such as ethylene (co)polymers
Implementation Method 3
The use of compounds of formula (I) as internal donors in Ziegler-Natta catalysts, particularly for ethylene (co)polymerization
Data Source
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Figure 3
AI summary
The present invention relates to optionally substituted 1,3-dimethoxypropanes and 3- methoxypropylamines, and more particularly to their use as internal donors in Ziegler-Natta catalysts to obtain polymers with desirable properties. The present disclosure further concerns Ziegler-Natta catalyst components comprising said optionally substituted 1,3- dimethoxypropanes and 3-methoxypropylamines, and Ziegler-Natta catalysts for olefin polymerization comprising said Ziegler-Natta catalyst components, as well as a method for preparing the same and their use in providing polyolefins.