High Temperature TEMPO Oxidation in a Heterogeneous Reaction System: An Investigation of Reaction Kinetics, Pulp Properties, and Disintegration Behavior
Artikel i vetenskaplig tidskrift, 2013

TEMPO oxidation was performed on never-dried bleached softwood kraft pulp fibres to study the influence of reaction temperature and the dosage of sodium hypochlorite in the oxidation treatment. It was found that oxidation at a high temperature shortened oxidation time, but it also resulted in more extensive degradation of the pulp. Harsh reaction conditions (high temperature and high dosage of sodium hypochlorite) enabled the rapid disintegration of pulp fibres with a low energy demand. The freeze-dried disintegrated pulp fibres had a high absorption capacity of saline liquid, 40 to 80 g/g, and retained 9 to 14 g saline liquid/g material in a standard centrifuge retention test. Four different models were investigated to describe the kinetics of TEMPO oxidation of pulp fibres. However, none of the models could adequately describe all the mechanisms involved in this reaction system. The results showed that the diffusion of hypochlorite ions was sufficiently fast compared to the chemical reactions. In contrast, the concentration of the catalytic compounds, NaBr and TEMPO, both had a strong influence on the reaction rate. Results show that the reactions have different phases, possibly with different rate-determining steps. It remains to be determined which reaction steps correspond to the different phases.

MFC

Retention

Kinetics

Fibres

TEMPO oxidation

Absorption

Diffusion

SELECTIVE OXIDATION

NATIVE CELLULOSE

FIBERS

MEDIATED OXIDATION

Författare

Fredrik Wernersson Brodin

Chalmers, Kemi- och bioteknik, Skogsindustriell kemiteknik

Hans Theliander

Wallenberg Wood Science Center (WWSC)

Chalmers, Kemi- och bioteknik, Skogsindustriell kemiteknik

BioResources

1930-2126 (ISSN)

Vol. 8 4 5925-5946

Ämneskategorier

Kemi

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Senast uppdaterat

2018-08-27