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Identification of decomposition reactions for HMDSO organosilicon using quantum chemical calculations
Author(s) -
Huang Yaosong,
Chen Yugong,
Zhou Mingfei
Publication year - 2020
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/qua.26415
Subject(s) - hexamethyldisiloxane , organosilicon , chemistry , dissociation (chemistry) , decomposition , bond dissociation energy , activation energy , molecule , chemical decomposition , chemical process of decomposition , photochemistry , computational chemistry , organic chemistry , plasma , physics , quantum mechanics
Hexamethyldisiloxane [HMDSO, (CH 3 ) 3 ‐SiOSi‐(CH 3 ) 3 ] is an important precursor for SiO 2 formation during flame‐based silica material synthesis. As a result, HMDSO reactions in flame have been widely investigated experimentally, and many results have indicated that HMDSO decomposition reactions occur very early in this process. In this paper, quantum chemical calculations are performed to identify the initial decomposition of HMDSO and its subsequent reactions using the density functional theory at the level of B3LYP/6‐311+G (d, p). Four reaction pathways—(a) SiO bond dissociation of HMDSO, (b) SiC bond dissociation of HMDSO, (c) dissociation and recombination of SiO and SiC bonds, and (d) elimination of a methane molecule from HMDSO—have been examined and identified. From the results, it is found that the barrier of 84.38 kcal/mol and SiO bond dissociation energy of 21.55 kcal/mol are required for the initial decomposition reaction of HMDSO in the first pathway, but the highest free energy barrier (100.69 kcal/mol) is found in the third reaction pathway. By comparing the free energy barriers and reaction rate constants, it is concluded that the most possible initial decomposition reaction of HMDSO is to eliminate the CH 3 radical by SiC bond dissociation.