Hofmann degradation kinetics of n-octylamine adsorbed on layered aluminosilicates prepared from apophyllite

Yu Sogo, Tsutomu Kumazawa, Ken Okihara, Atsushi Yamazaki

    Research output: Contribution to journalArticle

    Abstract

    Kinetic analyses of the Hofmann degradation of n-octylamine adsorbed on layered aluminosilicates prepared from apophyllite are reported. The data were collected by simultaneous thermogravimetry and evolved gas analysis (TG-DTG-EGA). Based on Kissinger plots using the DTG data, it is indicated that the activation energy of the Hofmann degradation increases with increasing Al/Si ratio of the layered aluminosilicates. Using the EGA data for l-octene, a similar tendency is observed. However, there is no such tendency for the results using the EGA data for ammonia. This indicates that ammonia remain on the surface after the Hofmann degradation. Hence, the activation energy obtained for ammonia is not that of the noctylamine decomposition, but from the analyses, using Ozawa's method, no tendency is observed in the relationship between the activation energy and the Al/Si ratio of the samples. This indicates that the Hofmann degradation is not a single elementary reaction in the strict meaning. However, the reaction mechanism could be estimated; e.g. two-dimensional dispersion (D2) for the sample with an Al/Si ratio in the range of 0.13-0.18 and three-dimensional dispersion (D4) for the Al/Si ratio of 0.05-0.09.

    Original languageEnglish
    Pages (from-to)193-201
    Number of pages9
    JournalThermochimica Acta
    Volume364
    Issue number1-2
    DOIs
    Publication statusPublished - 2000 Dec 1

    Fingerprint

    Aluminosilicates
    Ammonia
    degradation
    ammonia
    Degradation
    tendencies
    Kinetics
    Activation energy
    kinetics
    activation energy
    Gas fuel analysis
    gas analysis
    thermogravimetry
    Thermogravimetric analysis
    plots
    Decomposition
    decomposition
    octylamine
    aluminosilicate

    Keywords

    • Apophyllite
    • Hofmann degradation
    • Kinetic analysis
    • Layered aluminosilicate
    • TG-DTA-EGA

    ASJC Scopus subject areas

    • Instrumentation
    • Condensed Matter Physics
    • Physical and Theoretical Chemistry

    Cite this

    Hofmann degradation kinetics of n-octylamine adsorbed on layered aluminosilicates prepared from apophyllite. / Sogo, Yu; Kumazawa, Tsutomu; Okihara, Ken; Yamazaki, Atsushi.

    In: Thermochimica Acta, Vol. 364, No. 1-2, 01.12.2000, p. 193-201.

    Research output: Contribution to journalArticle

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