NH3及氧化产物NO在CO2/O2下对正庚烷热解影响OA

To investigate the effect of ammonia(NH3)and oxidation product,nitric oxide(NO),on the pyrolysis of n-heptane(C7H16)under CO2/O2 atmosphere,quantum chemistry and synchrotron vacuum ultraviolet photoionization mass spectrometry(SVUV-PIMS)are used to analyze the pyrolysis process in different conditions.Firstly,the reaction sites of NO with the pyrolysis product methyl(CH3)were analyzed using electrostatic potential(ESP)and Fukui function methods,and the new reaction pathway was computed with the DFT/Restricted/B3LYP method and the 6～31G/+/d/p basis set in Gaussian.Secondly,a low-pressure flow reactor developed for SVUV-PIMS was employed to study the conditions of NH3/C7H16 and NO/C7H16,with pyrolysis products under an equivalence ratio of 0.5,600-975K,and 30Torr(1Torr=133.32Pa)being quantitatively analyzed.Finally,the different pyrolysis products generated under the two conditions are compared,with six representative pyrolysis products analyzed,and the pyrolysis pathways of C7H16 and NH3,as well as the new reaction pathway of NO with CH3 were discussed.The results showed that among the 25 and 24 pyrolysis products of NH3/C7H16 and NO/C7H16,ethylene(C2H4)had the highest mole fraction,0.95 and 0.88,respectively.NO shortens the reaction pathway of C7H16 pyrolysis,and the pyrolysis efficiency of C7H16 in the NO/C7H16 condition increased by 7.84%compared to the NH3/C7H16 condition after 825K,with the mole fractions of the pyrolysis products CH3,propylene(C3H6),and butene(C4H8)increasing by 38.19%,46.14%,and 53.63%,respectively.Reactions of NO with CH3,C3H6,and C4H8 only occured above 925K,and in the NO+CH3¾¾® HCN+H2O reaction pathway,the energy of the transition state TS5 was 21.24kcal/mol(1kcal=4.184kJ)higher than that of the reactants.