Theoretical Study On The Elimination Or Conversion Reaction Mechanism Of Nitrogen And Chlorine Atmosphere Pollutants And Carbon Dioxide

The green revolution is the theme of development strategy in 21st century,which have attracted considerable attentions.Its central issue is how to manage,control and prevent pollution of the environment leading to a high quality living environment.Controlling and elimination atmospheric pollution is one of the most difficult and important tasks.Theoretical study on reaction mechanism would not only be helpful to elucidate the products that are difficult and/or hard to be detected by experimental method but also be beneficial to provide accurate and reliable reaction information from microscopic viewpoint.On the basis of the data,the lifetime of pollution would be predicted.The conversion of pollutants to resources would be the better choice than only elimination.Carbon dioxide?CO₂?is a famous gas.It is also the cheap and abundant C1 resources.The conversion of CO₂ emitted into the atmosphere would both reduce the pollution and alleviate the problem of traditional fossil resource shortage.This thesis is divided into two parts.One part is the mechanism of atmospheric pollutants including nitrogen and chlorine atoms from human life and industrial production process.In this paper,density functional theory has been employed to study the reaction mechanism of HCNO+HO₂ reaction and CH₂ClCOCl unimolecular decomposition reaction and products information,and determine the main product.The other part is to study the mechanism of CO₂ into cyclic carbonate reaction catalysed by a series of pyridine ionic liquid catalytic,and to explore an green and efficient way of conversion CO₂.1.The mechanism of reaction HCNO+HO₂ is investigated by means of CCSD?T?/6-311+G?d,p?//B3LYP/6-311+G?d,p?method,in which Pi with the i=1,2,3,…,7 are involved,to determine a more reasonable pathway.Among four possible entrance patterns:?1?O-abstraction from HCNO to generate product P6?HCN+HO₃?,?2?H-abstraction from HCNO to generate product P7?CNO+HOOH?,?3?middle oxygen atom from HO₂ connect with carbon atom of HCNO to form d1?OO?H?C?H?NO?,?4?the terminal oxygen atom of HO₂ connect with carbon atom of HCNO to form a1?HC?OOH?NO?.The attack of oxygen to carbon is the most energetically feasible leading to complex a1.Starting from the a1,the rupture of O2–O3 bond to form P3?HC?O?NO+OH?is the most favorable pathway.Alternatively,the a1 undergoes N–O1 bond rotation to form the isomer a2.A concerted O2–O3bond and C–N bond cleavage leading to P4?OH+HCO+NO?is the secondary feasible pathway.Other three products P5?COH+HONO?,P6?HCN+HO3?,and P7?CNO+HOOH?are not energetically accessible because of higher barrier-consumed and/or complicated processes.2.The mechanism of chloroacetyl chloride?CH₂Cl COCl?decomposition is explored at the BMC-CCSD//BMK/6-311+G?d,p?level in this work.Eight pathways and ten transition states are located to search for more favorable pathways.Some dissociated pathways start from the trans-CH₂ClCOCl directly.Alternatively,the trans-CH₂ClCOCl would transform to the cis-CH₂ClCOCl.Then,the cis-CH₂ClCOCl would dissociate into the product with single or multi steps.Starting from the trans-CH₂ClCOCl,P1?CHClCO+HCl?is the most favorable product by the rupture of C1-H1 bond and C2-Cl2 bond and the formation of H1-Cl2 bond?Pathway 1?,due to the least step and the lowest barrier height.P2?CH₂Cl₂+CO?is the common product of both Pathway 2 and Pathway 4 those start from the trans-and cis-CH₂ClCOCl,respectively.Owing to the second lowest rate-determining barrier height,P2 is the second feasible product.P3?CH₂Cl?O?CCl?formed by the migration of O atom from C2 atom to Cl1atom is the most minor product because of the highest barrier height.Other products P4?CH₂Cl+CO+Cl?,P5?CH₂CO+Cl₂?,and P6?CH₂ClCO?Cl??formed by the attack of Cl2 atom to C1 atom,Cl1 atom,and O atom,respectively,are not energetically accessible because of higher barrier-consumed and/or complicated process.3.The mechanism of the coupling reaction of CO₂ with epoxide catalysed by a series of pyridinium-based ILs is theoretically investigated.The influences of the nature of cation,methylene chain length,and anion on the catalytic performance are explored.It has been proven that the catalytic activity of pyridinium-based IL is better than that of imidazolium-based and quaternary ammonium-based ILs.The moderate methylene chain length,i.e.,n=3,for the pyridinium-based IL is the best choice to achieve the higher catalytic activity.Otherwise four new ILs are designed by introduction of the-COOH,-OH,-SO₃H,and-NH₂ functional groups into the traditional pyridinium-based IL,respectively.Subsequently,the catalytic performance of four newly designed functionalized pyridinium-based ILs is explored.Only the carboxyl-functionalized pyridinium-based IL has better catalytic activity than the traditional pyridinium-based IL.It is expected that the theoretical investigation might provide helpful clues for further experiments.