| More efficient and non-polluting antiknock have been seeking since developing nonleaded gasoline. It is obviously that clarifying the mechanisms of antiknock has important effects on developing new antiknock. So far, the mechanism of the metal antiknock has been paid more attention. However, the studies of the mechanisms of non-metal antiknock will play an important part in exploring new antiknock in the future, with non-metal antiknock being employed increasingly and metal antiknock restricted. But the study of the mechanisms of non-metal antiknock has developed slowly due to the complex of the electron-transfer mechanisms or no electron-transfer properties under common condition. The electron-transfer properties of non-metal antiknock and the effects of peroxide have been investigated with electrochemical technique, aiming at exploying electrochemical method of studying the mechanism of antiknock which has variable quantivalency.Many aromatic amine, such as aniline and N-methylaniline and diphenylamine, whose antidetonating quality are excellent, are not only often employed as concocting ingredient of antiknock but also suitable to research with electrochemical methods. We investigated the electron-transfer properties of aromatic amine in 1,2-dichloroethane which is a common auxiliary ingredient of antiknock by cyclic voltammetry and situ UV spectra and ac impedance spectroscopy. The research results indicate that the electrochemical oxidation reactions of aromatic amine belong to the free radical reaction. Under the conditions of low concentration and non-protonic solvent, the cation free radical produce substituted benzidines by tail-tail couplings. However, the couplings of N-methylaniline and N,N-dimethylaniline appear diversifying.The role of antiknock is to eliminate peroxide produced by the combustion of gasoline in engine. We have presented some important evidences to the antiknocking mechanisms of aromatic amine through investigating the reactionsof aromatic amine and peroxide on the premise of analyzing the electrochemical properties of aromatic amine. As a result, the relationship of antidetonating quality and electrochemical properties has been discussed. The research results indicate that p-toluidine and N,N-dimethylaniline has no significant counts. However, the reaction of N-methylaniline and peroxide is the most striking. As a matter of fact, N-methylaniline and aniline and toluidine is generally employed. We have not found any reports that o-toluidine and N,N-dimethylaniline can be used as antiknock. The electrochemical properties of aromatic amine are in line with its' antidetonating quality and actual application. The study results further indicate that it is feasible that studying the mechanisms of antiknock by making use of the electrochemical properties, which has guiding purpose in seeking new antiknock. Moreover, our work can promote the development of the electrochemical polymerization of aromatic amine. |
