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论文类型：期刊论文

发表时间：2015-08-01

发表刊物：FUEL

收录刊物：SCIE、EI、Scopus

卷号：153

页面范围：70-77

ISSN号：0016-2361

关键字：Coal based model compounds; Bond dissociation enthalpies; Weak bond; Theoretical study

摘要：The homolytic bond dissociation enthalpies (BDE) of various bonds (C-H, C-C, C-O, and O-H) for coal based model compounds that are representative of the functionalities present in coal were computed by using a double-hybrid method mPW2PLYP. The BDE for C-H, C-C, C-O, O-H cover a range from 111.4 to 81.2 kcal/mol, 114.1 to 62.8 kcal/mol, 107.6 to 52.6 kcal/mol, and 111.2 to 86.6 kcal/mol, respectively. The so-called "weak bond'' in coal does not mean a specific bond type, but it is associated with the BDE and highly depends on the stabilization of the fragmented radicals. Our work suggests that the initiation steps of the coal pyrolysis are most probably the cleavage of C-O and C-C bond to form the phenoxy radical or benzyl radicals. With the increase of temperature, the loss of alkyl and hydrogen groups becomes feasible, whereas the phenyl-like radicals are the most difficult to form. (C) 2015 Elsevier Ltd. All rights reserved.