间甲基苯胺的电子转移机理及组分协同效应研究

【作者】 李运输；

【导师】 郁章玉；

【作者基本信息】 曲阜师范大学 ， 物理化学， 2008， 硕士

【摘要】 环保和节能对汽油产品的质量提出更高的要求,导致了非金属抗爆剂的使用会逐渐增多,非金属抗爆剂抗爆机理的研究将在抗爆剂的发展中起到重要作用,明确抗爆机理对抗爆剂的研制开发有着重要的实践意义。苯胺类化合物是一类性能良好的非金属抗爆剂,间甲基苯胺就是其中的一种代表性物质。而且间甲基苯胺具有电子转移性质,适于电化学研究。本文采用电化学技术研究间甲基苯胺的电子转移性质、过氧化氢的影响以及新型抗爆剂TKC组分之间的协同效应,旨在探讨非金属抗爆剂的抗爆机理以及明确抗爆剂组分的性能,为组分优选工作与寻找最佳配比提供理论依据。本文采用循环伏安法分别研究了间甲基苯胺在1,2-二氯乙烷和甲醇溶液中的电子转移性质,实验结果表明:甲醇作为极性质子溶剂,可以结合质子形成质子化甲醇离子CH₃OH₂⁺,有利于间甲基苯胺偶合过程中的脱质子,能够促进正离子自由基的生成;而1,2-二氯乙烷是一种非质子溶剂,没有该促进作用。通过现场紫外-可见光谱电化学法研究了间甲基苯胺在甲醇溶液中的紫外-可见光谱性质,在此基础上探讨了间甲基苯胺的电子转移机理。间甲基苯胺在甲醇中发生电化学氧化时首先产生正离子自由基,在随后的化学反应中,正离子自由基聚合方式主要为“尾-尾”耦合,电极反应机理为包含随后转化步骤的EECE反应过程。汽油抗爆剂抗爆性的本质在于消除汽油燃烧过程中产生的过氧化物。本文在分析间甲基苯胺电化学性质的基础上,通过研究间甲基苯胺与过氧化氢的作用,为芳香胺抗爆机理的研究提供了重要依据,并由此探讨抗爆剂的抗爆性与电化学性质的关系。实验结果表明:间甲基苯胺能与过氧化氢发生作用,添加到汽油中可能有效去除过氧化物,起到抗爆震作用。在汽油调合时,各种调合组份的调合辛烷值与该物料在纯净状态下的辛烷值是不尽相同的,各调合组份间存在着调合效应。本文以TKC主要组分甲苯、乙酸丁酯、四氯乙烯、1,2-二氯乙烷分别与甲醇混合,在室温条件下利用循环伏安法研究间甲基苯胺在不同实验组分中的电子转移性质及与过氧化氢的相互作用,进而分析甲醇与它们之间的协同作用。实验发现:当甲苯、乙酸丁酯、四氯乙烯添加量为10%时,间甲基苯胺的氧化峰电流最大。表明甲苯、乙酸丁酯、四氯乙烯添加量少时表现出正调合效应,有利于间甲基苯胺对过氧化物的消除。更多还原

【Abstract】 The quality of gasoline is much higher with the reqirements of environmental protection and energy conservation. This leads to the more application of non-metal antiknock .The studies of the mechanisms of non-metal antiknock will play an important role in exploring new antiknock in the future. So clarifying the mechanisms of antiknock has important effects on developing new antiknock. Aniline compounds has a good performance of the non-metallic antiknock additive, m-Toluidine which has the nature of electron transfer is one of the representative material and suitable to research with electrochemical methods. In this paper, we have investigated the electron-transfer properties of m-Toluidine and the effects of hydrogen peroxide and the co-effect of constituents of TKC with electrochemical technique, aiming at exploring the mechanism of antiknock and definiting the properties of constituents of antiknock. This will provide the theoretical basis for selecting components and finding the best proportion.We have investigated the electron-transfer properties of m-Toluidine in 1, 2-dichloroethane and methanol by cyclic voltammetry. The experimental results show that methanol as a polar protic solvent can combine with proton to form protonated methanol ion. It is propitious to delink proton in the coupling process of m-Toluidine, which can promote the formation of the free cation radical. 1, 2-dichloroethane as an aprotic solvent hasn’t the promoting role. We also studied the spectral properties of m-Toluidine in methanol with situ UV spectra. The mechanism is that the free cation radical of m-Toluidine can form dimers by tail-tail coupling in methanol. The electrode process is considered to be followed by ECE mechanism.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 m-Toluidine through investigating the reactions of m-Toluidine and hydrogen peroxide on the premise of analyzing the electrochemical properties of m-Toluidine. As a result, the relationship of antidetonating quality and electrochemical properties has been discussed. The experimental results indicate that m-Toluidine could eliminate hydrogen peroxide. m-Toluidine maybe eliminate peroxide effectively when it is added in the petrol and play a role of antiknock.As gasoline blending, the octane number of various blending components is different with the material in the pure state’s, in which blending effect exists. In this paper, toluene, perchloroethylene, butyl acetate, 1, 2-dichloroethane, which are the main components of TKC, are blended with methanol respectively. We study the electron-transfer properties of m-Toluidine in different components and interaction with hydrogen peroxide by cyclic voltammetry at room temperature. It is found that when toluene, butyl acetate, perchloroethylene is added respectively to 10%, the oxidation peak current of m-Toluidine is the largest. When there is a little toluene, butyl acetate and perchloroethylene , it can manifest positive concocting effect and do good favor to eliminate peroxide with m-Toluidine.更多还原