کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
1197859 964667 2011 12 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Thermal reactivities of catechols/pyrogallols and cresols/xylenols as lignin pyrolysis intermediates
موضوعات مرتبط
مهندسی و علوم پایه شیمی شیمی آنالیزی یا شیمی تجزیه
پیش نمایش صفحه اول مقاله
Thermal reactivities of catechols/pyrogallols and cresols/xylenols as lignin pyrolysis intermediates
چکیده انگلیسی

Thermal reactivities of lignin pyrolysis intermediates, catechols/pyrogallols (O-CH3 homolysis products) and cresols/xylenols (OCH3 rearrangement products), were studied in a closed ampoule reactor (N2/600 °C/40–600 s) to understand their roles in the secondary reactions step. Reactivity tends to be enhanced by increasing the number of substituent groups on phenol and this effect was greater for –OH than for –CH3. Thus, catechols/pyrogallols were more reactive than cresols/xylenols and syringol-derived products were more reactive than corresponding guaiacol-derived products. Catechols/pyrogallols were effectively converted into CO (additionally CO2 in the case of pyrogallols) in the early stage of pyrolysis. In contrast, cresols/xylenols were comparatively stable and produced H2, CH4 and demethylation products (cresols and phenol) after prolonged heating. All intermediates except phenol and 2-ethylphenol formed coke during a long heating time of 600 s (second stage coking). Based on the present results, the roles of intermediates in tar, coke and gas formation from guaiacol and syringol are discussed at the molecular level, focusing on their differences. Molecular mechanisms of gas formation from pyrogallols and demethylation of cresols/xylenols are also discussed.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Analytical and Applied Pyrolysis - Volume 92, Issue 1, September 2011, Pages 76–87
نویسندگان
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