Pyrolysis studies on the structure of ethers and phenols in coal

Coal pyrolysis characteristics by TG–MS and its late gas generation potential

“…The first and second peak temperatures of CO evolution is close to the peak temperature of aliphatic hydrocarbon, toluene, xylene and benzene (Fig. 5), strongly suggesting that CO formation may be controlled by the decomposition of aliphatic-aliphatic ether structures or aliphatic-aromatic ether structures, which is also in agreement with what reported by Siskin and Aczel [47]. However, when temperature is higher than 700°C, the generation of CO probably is mainly influenced by the Boudouard equilibrium reaction:…”

Study on the formation of phenols during coal flash pyrolysis using pyrolysis-GC/MS

“…Tables 2 and 3 show that the amount of phenols obtained from the coal pyrolysis was much higher than that in the coal extracts. Under the heating conditions, the weak C\C and C\O bonds of diverse types of linkages, such as ether linkages, connecting condensed aromatic and hydroaromatic units in the coal macromolecular structure were cleaved [26][27][28][29]. Thus, the emission of phenolic compounds during the coal pyrolysis is largely due to the thermal cracking of oxygen-containing structures rather than the escape of phenols already existing in the raw coals.…”

“…During the coal flash pyrolysis, phenolic compounds separated from the gaseous products are generated by the cleavage of ether bond of aryl ethers in the temperature range of 500-800°C, similar to that in a polymer in which the aryl ether segments are bonded through keto and methylene groups to the neighboring segments [26][27][28].…”

Application of Spectroscopic Techniques to the Structural Analysis of Coal

“…Spectroscopic methods have been applied to the qualitative analysis of ether bonds in coal (Barron and Wilson, 1981;Painter et al, 1981 Siskin and Aczel, 1983; Yoshida et al, 1984;Mallya and Zingaro, 1984; Youtcheff and Given, 1982;Given 1984a;Den0 et al, 1985;Stock, 1988;Franco et al, 1992) with some degree of success. Indeed, there is evidence to presume that the ether bond in coal is mainly of the diary1 ( A r U A r ) and benzyl-aryl ( C , H , C H , U A r ) types although methoxyl groups (CH,O-) and dialkyl ethers ( R U R ' ) are found in low-rank coals (Bredenberg et al, 1987).…”