Combustion Kinetics Of The Addition And Migration Ractions With Phenyl Radical

Combustion is highly related to human's regular life and economy and is an important form of utilization of fossil energy,which is mainly composed of hydrocarbons,such as natural gas,coal and petroleum.In addition to heat,the combustion of fossil fuels also produces a series of pollutants,causing serious environmental problems.Those pollutants mainly include hydrocarbons,carbon monoxide,nitrogen oxides,sulfur oxides,carbon dioxide and soots etc.Combustion chemical kinetics is a subject which studies the energy release during combustion process and the formation mechanism of combustion pollutants.The combustion reaction mechanism of hydrocarbons is an important subject in the study of combustion chemical kinetics.Therefore the formation mechanism of combustion pollutants is also an important part of hydrocarbon combustion reaction mechanism.Among those kinds of pollutants,the generation of fine particulate matter(PM)in air pollutants is closely related to combustion.Soots,as the main component of fine particulate matter,its main mass source is polycyclic aromatic hydrocarbons(PAHs).Phenyl group plays a very important role in the generation of polycyclic aromatic hydrocarbons by combustion,so it is very meaningful to study the combustion reaction kinetics of phenyl groups.There are many types of reactions related to phenyl groups in combustion,and the study of these reaction types in combustion kinetics can be related to the precise reaction rate of a single key reaction system,or to the regularity of many similar reactions.In this thesis,the addition reaction of phenyl and acetylene,which is one of the key reactions in the formation mechanism of PAHs,is calculated with high accuracy quantum chemistry and kinetics method.The results show that the branch ratio of main products of reaction will change greatly under different temperature and pressure,which indicates that the experimental or theoretical conclusion under low pressure is probably not applicable under high pressure.The reaction rules of phenyl migration reactions and similar reactions in many combustion systems were studied in this thesis using quantum chemistry and kinetics calculation.Computational results show that for an alkenyl or aromatic radical with the radical site located at the ? position to the vinyl or phenyl group,the 1,2-vinyl/phenyl migration is the main consumption path corresponding to the free radicals at relatively low temperature(<1500 k),and still have noticeable contribution at higher temperature although the entropy effect becomes more significant.Since the calculation accuracy is different when using different research methods,in order to evaluate the influence of calculation with different accuracy on apparent rate constant in reaction kinetics,the uncertainty of rate constant in reaction kinetics was studied by combining theoretical error transfer analysis and sample statistical analysis.By comparing the two methods,it is found that the theoretical error propagation analysis method,which has relatively low calculation cost,can be applied to analysis the uncentainty of rate constants at high pressure limit and the uncertainty of rate constants of unimolecule reaction at practical pressures.Some improvements are still needed for theoretical error transfer analysis to predict the precise uncertainty of rate constants in more complex reaction systems.