Radical pathways in the thermal decomposition of pyridine and diazines: a laser pyrolysis and semi-empirical study

被引:42
作者
Hore, NR [1 ]
Russell, DK [1 ]
机构
[1] Univ Auckland, Dept Chem, Auckland 1, New Zealand
来源
JOURNAL OF THE CHEMICAL SOCIETY-PERKIN TRANSACTIONS 2 | 1998年 / 02期
关键词
D O I
10.1039/a706731c
中图分类号
O62 [有机化学];
学科分类号
070303 ; 081704 ;
摘要
The mechanisms of thermal decomposition of pyridine and the three isomeric diazines have been investigated by IR laser pyrolysis in conjunction with stable end-product analysis by FTIR, NMR and GC-MS, and radical detection by EPR spectroscopy, Calculations at semi-empirical and ab initio levels have provided confirmation of potential reaction pathways, For pyridine, reaction is initiated by formation of pyridyl radicals, as indicated by extensive isotope exchange with added deuterium, Experiments with bromopyridines show that open chain radicals arising from ring opening of 2-pyridyl and 3-pyridyl radicals each lead to stable gaseous produces, while 4-pyridyl radicals produce solid deposits, and may be the principal agents in soot formation, The evidence suggests that 1,2-diazine decomposes via a molecular route leading to stoichiometric production of HCN and C2H2, while 1,3- and 1,4-diazine follow a pattern of H loss and ring radical opening analogous to that of pyridine.
引用
收藏
页码:269 / 275
页数:7
相关论文
共 31 条
[21]  
PERSHING DW, 1977, 16TH S INT COMB PITT, P389
[22]  
POLA J, 1981, COLLECT CZECH CHEM C, V46, P2856
[23]  
ROTH CF, 1886, BER, V19, P360
[24]   THE HITRAN DATABASE - 1986 EDITION [J].
ROTHMAN, LS ;
GAMACHE, RR ;
GOLDMAN, A ;
BROWN, LR ;
TOTH, RA ;
PICKETT, HM ;
POYNTER, RL ;
FLAUD, JM ;
CAMYPEYRET, C ;
BARBE, A ;
HUSSON, N ;
RINSLAND, CP ;
SMITH, MAH .
APPLIED OPTICS, 1987, 26 (19) :4058-4097
[25]  
RUHEMANN S, 1929, BRAUNKOHLE, V28, P749
[26]   INFRARED-LASER POWERED HOMOGENEOUS PYROLYSIS [J].
RUSSELL, DK .
CHEMICAL SOCIETY REVIEWS, 1990, 19 (04) :407-437
[27]   ALUMINUM AND GALLIUM ALKYLS AND THEIR DERIVATIVES - SPECTROSCOPIC AND LASER PYROLYSIS STUDIES OF METAL-DEPOSITION PRECURSORS [J].
RUSSELL, DK .
COORDINATION CHEMISTRY REVIEWS, 1992, 112 :131-168
[28]   Gas-phase pyrolysis mechanisms in organometallic CVD [J].
Russell, DK .
CHEMICAL VAPOR DEPOSITION, 1996, 2 (06) :223-&
[29]   LASER-POWERED HOMOGENEOUS PYROLYSIS [J].
SHAUB, WM ;
BAUER, SH .
INTERNATIONAL JOURNAL OF CHEMICAL KINETICS, 1975, 7 (04) :509-529
[30]   SPECIAL ISSUE - MOPAC - A SEMIEMPIRICAL MOLECULAR-ORBITAL PROGRAM [J].
STEWART, JJP .
JOURNAL OF COMPUTER-AIDED MOLECULAR DESIGN, 1990, 4 (01) :1-45