Superficially Porous Metal Oxide Particles via Pseudomorphic Transformation
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Solution Overview
Problem
Conventional methods for producing superficially porous silica particles result in particles with broad particle size distributions, rough surfaces, and randomly distributed pores, leading to inefficiencies in chromatography due to high film mass transfer resistance and reduced packing density.
Innovation Solution
A method involving pseudomorphic transformation of solid metal oxide particles in an aqueous solution with surfactants and swelling agents to create particles with ordered pores and narrow size distributions, maintaining the original particle size and morphology while forming a porous outer shell.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional methods (spray-drying, multilayer technology, coacervation) are used to prepare superficially porous silica particles, then particles with porous outer shells are produced, but the particles exhibit broad particle size distributions and rough surfaces
Solution Approach 1:
The invention changes the chemical composition parameters of the silica sol, specifically using a silica sol with a SiO2/Al2O3 ratio of 95:5 or higher and a pH of 7-9, which enables controlled hydrolysis and condensation reactions that produce smooth surfaces and narrow particle size distributions during the coating process
Solution Approach 2:
The invention replaces mechanical coating methods with chemically controlled coating by utilizing controlled hydrolysis and condensation reactions of silica sol on the particle surfaces, which naturally produce uniform and smooth coatings without mechanical roughness
2Speed
If conventional methods are used to create porous outer shells, then mass transfer is improved, but pores are randomly distributed leading to high film mass transfer resistance
Solution Approach 1:
The invention uses a controlled chemical reaction process where silica sol acts as an intermediary that uniformly deposits on particle surfaces through hydrolysis and condensation, creating evenly distributed pores rather than random pore formation
Solution Approach 2:
By controlling the pH (7-9) and composition (SiO2/Al2O3 ≥ 95:5) of the silica sol, the invention achieves uniform pore distribution while maintaining high mass transfer rates through the porous shell
3Quantity of substance
If rough particle surfaces are produced by conventional methods, then porous structure is achieved, but packing density is reduced due to increased friction forces
Solution Approach 1:
The invention changes the silica sol parameters (pH 7-9, SiO2/Al2O3 ≥ 95:5) to enable controlled chemical coating that produces smooth surfaces while maintaining adequate porous shell content for chromatographic function
Solution Approach 2:
The invention replaces mechanical mixing and coating methods with chemically controlled deposition, where silica sol naturally coats particles through hydrolysis and condensation, producing smooth surfaces that reduce inter-particle friction and improve packing density
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 resulting particles exhibit improved chromatographic performance with faster separation, lower pressure drop, and higher efficiency, maintaining mechanical strength and stability at high pH.
Implementation Method 1
subjecting substantially solid metal oxide particles to pseudomorphic transformation in an aqueous solution with surfactants and swelling agents to create particles with ordered pores and narrow size distributions
Implementation Method 2
micelle-templated synthesis produces a more ordered pore framework involving preformed micellar structures via a liquid crystal templating mechanism
Implementation Method 3
subjecting substantially solid metal oxide particles to pseudomorphic transformation in an aqueous solution with surfactants and swelling agents
Data Source
AI summary
Superficially porous hybrid particles include hybrid solid cores that each contain an inorganic material and an organic material; and porous hybrid outer shells each include the inorganic and organic materials and having ordered pores, wherein the ordered pores have a median pore size ranges from about 15 to about 1000 Å with a pore size distribution (one standard deviation) of no more than 50% of the median pore size and produce at least one X-ray diffraction peak between 0.01° and 10° of a 2θ scan range; wherein the particles have a median size range from about 0.5 μm to about 100 μm with a particle size distribution (one standard deviation) of no more than 15% of the median particle size, wherein the inorganic material comprises a metal oxide selected from silica, alumina, titania or zirconia.