| Summary: | 碩士 === 國立交通大學 === 應用化學系碩博士班 === 107 === The kinetics and mechanisms for reactions of Nitrogen Tetroxide (N2O4, NTO) with Ammonia (NH3) and Methylamine (CH3NH2) have been studied by quantum chemical calculations at the UCCSD(T)//UB3LYP/6-311+G(3df,2p) level of theory. These chemical reactions are related to the well-known NTO-hydrazine(s) propellant systems. Based on the predicted detailed potential energy surfaces (PES), the mechanisms for these reactions were found to be similar to the hydrolysis of the NTO and the hypergolic initiation reaction of the NTO-N2H4 mixture, primarily controlled by the isomerization of NTO to ONONO2 via very loose roaming-like transition states (with NH3 and CH3NH2 as spectators), to be followed by the abstraction of a hydrogen atom by ONONO2 from the spectating molecules. We have compared the predicted kinetics and mechanism for the reaction of NH3 with its isoelectronic process NTO + H2O and the reaction of CH3NH2 with the isoelectronic NTO + NH2NH2 reaction. The mechanisms for these processes are all similar, but the kinetics for the formation of the final products HNO3 + RNO (R = NH2, OH, CH3NH and N2H3) are affected by the strengths of the H-NH2 and H-OH, but not influenced by those of H-NHCH3 and H-NHNH2, respectively.
|
|---|
