Propylene Polymerization Catalyst with Reverse Microcellular Structure
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Solution Overview
Problem
The existing Ziegler-Natta catalysts used for propylene polymerization suffer from poisoning issues, which are not effectively addressed by external electron donors, necessitating a novel catalyst composition that enhances catalyst activity and reduces poisoning.
Innovation Solution
A catalyst composition utilizing an ester compound with hydrophilic and hydrophobic groups as a modifying agent, which forms a reverse microcellular structure to trap polar substances and maintain the valence state of titanium at positive trivalent, thereby promoting polymerization reactions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If external electron donors are used to improve poisoning problems of Ziegler-Natta catalyst, then catalyst poisoning is reduced, but catalyst activity is not effectively enhanced
Solution Approach 1:
The patent uses a composite modifying agent comprising both a first modifying agent (electron donor compound) and a second modifying agent (ester compound with hydrophilic and hydrophobic groups). This composite approach combines the anti-poisoning benefits of electron donors with the microcellular structure formation capability of the ester compound, achieving both reduced catalyst poisoning and enhanced catalyst activity simultaneously.
Solution Approach 2:
The patent optimizes the molar ratio parameters of the modifying agents to titanium halide (first modifying agent: 0.01-2 mol/, second modifying agent: 0.01-2 mol/) and controls the molecular structure parameters of the ester compound (specific carbon chain lengths and ester group configurations). These parameter changes enable the modifying agent to form reverse microcellular structures that protect the catalyst while maintaining high activity.
2Reliability
If modifying agent forms reverse microcellular structure to trap polar substances, then catalyst poisoning is reduced, but catalyst activity enhancement is limited without proper valence state control
Solution Approach 1:
The ester compound modifying agent acts as an intermediary that forms reverse microcellular structures, trapping polar substances away from the catalyst active sites. Simultaneously, it maintains the appropriate titanium valence state, mediating between the need for catalyst protection and the need for high polymerization activity.
Solution Approach 2:
The modifying agent creates local microcellular environments around the catalyst particles where polar substances are excluded, while the bulk catalyst maintains its active titanium sites. This local quality change protects the catalyst interface without affecting the overall catalytic function.
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 solution effectively reduces catalyst poisoning, enhances catalyst activity, and decreases residual metal amounts in polypropylene, improving the polymerization process and product quality.
Implementation Method 1
The modifying agent can form a reverse microcellular structure, so that polar substances in a raw material are inside the reverse microcellular structure
Implementation Method 2
the modifying agent can maintain a valence state of titanium in an active site of the catalyst at positive trivalent to promote a polymerization reaction between the titanium and the monomer
Implementation Method 3
uses a Ziegler-Natta catalyst to promote a propylene polymerization reaction
Data Source
AI summary
The present disclosure relates to a catalyst composition for polymerizing propylene and a method for producing polypropylene. The catalyst composition for polymerizing the propylene includes a modifying agent. The modifying agent is an ester compound having hydrophilic groups and hydrophobic groups. In the method for producing the polypropylene, a reverse microcellular structure is formed by the modifying agent during a propylene polymerization, in which the hydrophilic groups are inside the reverse microcellular structure, and the hydrophobic groups are outside the reverse microcellular structure, such that polar substances in a raw material are retained inside the reverse microcellular structure. Thus, poisoning of the catalyst is reduced. Besides, the modifying agent can maintain a valence state of titanium in an active site of the catalyst at positive trivalent, such that the propylene polymerization between the titanium and the monomer is facilitated, thereby enhancing an activity of the catalyst.