Solid-acid catalysts functionalized with catalytic groups have attracted intense interest for converting cellulose into soluble products. However, design of solid-7 acid catalysts has been guided by molecular level interactions and the actual mechanism of cellulose-solid-acid catalyst particles adsorption remains unknown. Here, colloidal stability theory, DLVO, is used to rationalize the design of solid acids for targeted cellulose adsorption. In nearly all cases, an energy barrier, arising from electrostatic repulsion and much larger than the energy associated with thermal fluctuations, prevents close contact between the solid acid and cellulose. Polymer-based solid-acid substrates such as polystyrene and Nafion are especially ineffective as their interaction with cellulose is dominated by the repulsive electrostatic force. Carbon and metal oxides have potential to be effective for cellulose-solid-acid interaction as their attractive van der Waals interaction can offset the repulsive electrostatic interaction. The effects of reactor temperature and shear force were evaluated, with the finding that reactor temperature can minimize the catalyst-cellulose interaction barrier, promoting coagulation, but that the shear force in a typical laboratory reactor cannot. We have evaluated strategies for enhancing cellulose-catalyst interaction and conclude that raising reaction temperature or synthesizing acid/base bifunctional catalysts can effectively diminish electrostatic repulsion and promote cellulose-catalyst coagulation. The analysis presented here establishes a rational method for designing solid acid catalysts for cellulose hydrolysis.
Rational design of solid-acid catalysts for cellulose hydrolysis using colloidal theory.
Ziyang Zhang,G. Tompsett,S. Granados-Fócil,C. Lambert,M. Timko
Published 2021 in Physical Chemistry, Chemical Physics - PCCP
ABSTRACT
PUBLICATION RECORD
- Publication year
2021
- Venue
Physical Chemistry, Chemical Physics - PCCP
- Publication date
2021-04-22
- Fields of study
Medicine, Materials Science, Chemistry
- Identifiers
- External record
- Source metadata
Semantic Scholar, PubMed
CITATION MAP
EXTRACTION MAP
CLAIMS
CONCEPTS
- acid/base bifunctional catalysts
Catalysts that combine acidic and basic functional groups on the same material.
Aliases: acid-base bifunctional catalysts
- cellulose adsorption
The attachment of cellulose to catalyst particle surfaces in the reaction environment.
Aliases: cellulose-solid-acid adsorption, cellulose-catalyst adsorption
- dlvo theory
A colloidal stability framework that balances electrostatic repulsion and van der Waals attraction between interacting particles in solution.
Aliases: DLVO, colloidal stability theory
- electrostatic repulsion
The repulsive interaction arising from surface charge effects between cellulose and catalyst particles.
Aliases: electrostatic force, repulsive electrostatic interaction
- reactor temperature
The operating temperature used in the reaction reactor during cellulose hydrolysis experiments.
Aliases: temperature, reaction temperature
- shear force
Mechanical stress generated by fluid motion in the reactor and acting on particles in suspension.
Aliases: shear stress
- solid-acid catalysts
Solid catalyst materials functionalized with acidic groups and used here for cellulose hydrolysis.
Aliases: solid acids, solid acid catalysts
- van der waals interaction
The attractive dispersion interaction between cellulose and catalyst surfaces.
Aliases: van der Waals forces, dispersion interaction
REFERENCES
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