Electrical Double Layer as a Model of Interaction between Cellulose and Solid Acid Catalysts of Hydrolysis

Solid acid catalysts of cellulose hydrolysis in aqueous media attract considerable research interest because of the ease of their separation from the reaction products. The nature of interaction between the two solids is a relevant topic of ongoing research. One aspect of behavior of solid acids in...

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Bibliographic Details
Published in:Chemphyschem 2019-03, Vol.20 (5), p.706-718
Main Authors: Tarabanko, Nikolay, Tarabanko, Valery E., Kukhtetskiy, Sergey V., Taran, Oxana P.
Format: Article
Language:English
Subjects:
acid catalysis
Aqueous solutions
Brownian motion
Carbohydrates
Catalysis
Catalysts
Cellulose
cellulose hydrolysis
Chemisorption
Electric double layer
electrostatic interactions
heterogeneous catalysis
Hydrolysis
Organic chemistry
Polyelectrolytes
Protonation
Reaction products
Solid surfaces
thermodynamics
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Summary:Solid acid catalysts of cellulose hydrolysis in aqueous media attract considerable research interest because of the ease of their separation from the reaction products. The nature of interaction between the two solids is a relevant topic of ongoing research. One aspect of behavior of solid acids in water was not previously discussed in literature with regard to hydrolysis of cellulose: electrolytic dissociation and formation of electric double layers. In this work, on theoretical level, we consider the role of the double layer created by the solid acid when cellulose hydrolysis takes place. The diffuse layer of protons is regarded as the medium where the hydrolysis reaction occurs. Protonation of cellulose by these protons imparts positive charge onto its surface, and cellulose is electrostatically attracted to the polyanion of the catalyst. Thus, the two solid surfaces stay close to each other despite Brownian motion; this allows explaining the high activity of solid catalysts even when chemisorption of carbohydrates on a catalyst is not favorable. The role of the electrical double layer between dissociated solid acid catalyst and cellulose during hydrolysis is considered on theoretical level. Substantial proton concentrations are predicted in the range of a few nanometers from the catalyst surface. This allows extending the action of the catalyst beyond its surface. Protonated cellulose attracts to the catalyst (which ensures constant contact and enhances chemisorption), and the diffuse proton layer can also catalyze hydrolysis.
ISSN:1439-4235
1439-7641
DOI:10.1002/cphc.201801160