Kinetics of the oxidative ammonolysis of lignin

Ewellyn A. Capanema*, Mikhail Balakshin

*Tämän työn vastaava kirjoittaja

Tutkimustuotos: Artikkeli kirjassa/konferenssijulkaisussaChapterScientificvertaisarvioitu

Abstrakti

The effect of reaction variables on the oxidative ammonolysis of technical lignins was studied in the range of 0.4-0.8 M NH4OH, reaction temperature of 70 - 130°C, oxygen pressure of 0.5 - 1.2 MPa and pH 9- 12.7. The kinetics of nitrogen incorporation consists of two phases, both of which follow a pseudo-first order reaction law. The reaction is 1st and 0.5 order with respect to oxygen and NH4OH concentration, respectively. The effective activation energy of nitrogen incorporation is rather low, 33-43 kJ/mol. The dependence of the reaction rate on pH of the reaction solution goes through a maximum. Linear correlation between nitrogen incorporation and O-demethylation, CO2 formation, oxygen uptake as well as oxygen incorporation were observed. Structural analyses of the soluble N-modified lignins by FTIR and 1H NMR spectroscopic techniques showed only qualitative differences of the spectra obtained under different reaction conditions indicating that the reaction conditions do not affect the reaction pathways. A scheme of possible reaction mechanisms is postulated based on the experimental results.

AlkuperäiskieliEnglanti
OtsikkoWhat to Know about Lignin
KustantajaNOVA SCIENCE PUBLISHERS
Sivut303-328
Sivumäärä26
ISBN (elektroninen)978-1-5361-9222-3
ISBN (painettu)978-1-53619-152-3
TilaJulkaistu - 28 tammik. 2021
OKM-julkaisutyyppiA3 Kirjan osa tai toinen tutkimuskirja

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