Fluorided Silica-Coated Alumina Supports for Lower Metallocene Loading
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Solution Overview
Problem
Existing metallocene-based catalyst systems for olefin polymerization require high amounts of metallocene components, leading to increased costs, and there is a need for solid activator-supports with enhanced catalytic activity to reduce this requirement.
Innovation Solution
Development of fluorided silica-coated alumina activator-supports with high pore volume and porosity, characterized by specific bulk density, BET surface area, and average pore diameter, which enhance the adsorption of metallocene compounds, thereby increasing catalytic activity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high amounts of metallocene components are used in catalyst systems, then catalytic activity is maintained, but costs increase
Solution Approach 1:
The patent employs porous silica-coated alumina supports with controlled pore size distributions (mesopores and macropores) to enhance metallocene compound adsorption. The porous structure provides high surface area and volumetric activity, allowing reduced metallocene loading while maintaining catalytic performance. Pore volume and surface area are optimized to maximize catalyst activity per unit mass of metallocene.
Solution Approach 2:
The invention uses composite catalyst systems combining metallocene compounds with fluorided silica-coated alumina supports. This composite approach leverages the synergistic effects of the organic metallocene catalyst and inorganic porous support, where the support provides structural framework and metallocene anchoring sites, while the metallocene provides catalytic function. The composite structure enables reduced metallocene content while maintaining high activity through improved dispersion and interaction with support sites.
2Quantity of substance
If solid activator-supports with enhanced catalytic activity are developed, then metallocene requirement is reduced, but manufacturing complexity increases
Solution Approach 1:
The patent employs preliminary coating of alumina particles with silica before fluorination treatment. This pre-treatment creates a silica layer that facilitates subsequent fluorine incorporation and defines the final porous structure. The sequential preparation (alumina synthesis → silica coating → fluorination → pore formation) allows each step to be optimized independently, simplifying manufacturing while achieving the target porosity and surface area characteristics.
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 fluorided silica-coated alumina supports significantly increase the catalytic activity, allowing for reduced metallocene usage and cost savings while producing ethylene polymers with desired properties.
Implementation Method 1
the fluorided silica-coated alumina supports significantly increase the catalytic activity, allowing for reduced metallocene usage
Data Source
AI summary
Fluorided silica-coated alumina activator-supports have a bulk density from 0.15 to 0.37 g/mL, a total pore volume from 0.85 to 2 mL/g, a BET surface area from 200 to 500 m2/g, an average pore diameter from 10 to 25 nm, and from 80 to 99% of pore volume in pores with diameters of greater than 6 nm. Methods of making the fluorided silica-coated alumina activator-supports and using the fluorided silica-coated aluminas in catalyst compositions and olefin polymerization processes also are described. Representative ethylene-based polymers produced using the compositions and processes have a melt index of 0.1 to 10 g/10 min and a density of 0.91 to 0.96 g/cm3, and contain from 70 to 270 ppm solid oxide and from 2 to 18 ppm fluorine.