Structure of the residual carbon made by fluorocarbon pyrolysis

Fialkov, Anastasia; Dobryakov, S. N.; Khorkhorin, A. V.; Tyan, L. S.; Polyakova, N. V.; Kuznetsov, Yu. N.; Yurkovskii, I. M.

doi:10.1007/bf00743579

Cited by 2 publications

(1 citation statement)

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“…3). This line is similar to that observed in the EPR spectrum of fluorinated carbon [10]. We suppose that the broad-component line is a result of strong hyperfine interactions between unpaired electrons and nuclei of fluorine isotope 19F (I = 1/2).…”

Section: Results and Diseussionsupporting

confidence: 64%

EPR study of coke formed on alumina

et al. 2003

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This study was aimed at characterizing paramagnetic properties of cokes formed on aluminas of different origin (calcined at 400 and 800~ during catalytic reactions of hexafluoro-2-propanol decomposition and, for the sake of comparison, 2-propanol decomposition at 300 and 400~ No significant differences in coke-forming activities were found between alumina obtained by hydrolys[s of alurninium isopropoxide and that prepared by precipitation with ammonia from aluminium sulfate solution at pH 6.1, although they differed substantially in their acidity patterns. On the other hand, clear differences were observed between intensities of electron paramagnetic resonance (EPR) spectra recorded for samples covered with coke produced by reactions of the two alcohols. When hexafluoro-2-propanol was the parent substance, spectral lines were stronger and narrower than those obtained for 2-propanol. The smaller linewidth (ABvp = 0.29-0.54 tot compared to ABpp = 0.51-0.92 mT) was most likely a result of exchange interactions between electrons of paramagnetic centers, whose concentrations were higher in the carbonaceous deposit formed from fluorine-containing alcohol. Higher temperature of coke formation (400~ resulted in higher intensities of EPR spectra, whereas higher temperature of alumina calcination (800~ prior to its use in alcohol decomposition reaction, brought about lower spectral intensities.

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Section: Results and Diseussionsupporting

confidence: 64%