Study On Synthesis Of 2-ethylhexoic Acid By Oxidation Of 2-ethylhexanol Using O₂

It is an important organic synthesis reaction that under the influence of oxygen, alcohol is conversed to be acid by catalytic oxidation. This is widely used in organic synthesis and precision chemistry. These years, with the promotion of environmental protection, due to the toxicity and strong causticity of traditional strong oxidizers, traditional strong oxidizer become unsuitable for the need of social development. Thus, the use of clean O2 and H2O2 as oxidizers and the development of green, moderate and efficient catalytic system to change organic alcohol into acid have become the focus of current research.The thesis chooses 2-ethylhexoic acid, a widely used chemical in dope and printing ink industries, as the desired product, with the oxidation of 2-ethylhexanol in one step. In this process, oxygen is used as the oxidizer and the catalyst is provided by the author. Through the optimization of catalyst's producing condition and the discussion of oxidative technical, an efficient, environment-friendly, high-selective method of oxidation of alcohols is provided.Firstly, with Al2O3 as the carrier, it adopts method of impregnation to produce a series of transition-metal oxide catalyst. Through the 2-ethylhexanol oxidation experiment, it selects two active catalyst, namely ZnO/Al2O3 and MgO/Al2O3. How their producing condition influences the activity of catalyst is observed here. It also studied the relation between the presentation of catalysts and their producing condition and activity by the use of XRD.BET and TG-DTG. It turns out that at the calcination temperature of 800℃,4%ZnO/Al2O3 has the best conversion, selectivity and yield, that is 42.4% and 18.1%. The product spinel plays an essential role in increasing the activity of the catalysts.On the basis of single component catalyst, poly-component catalyst is produced by impregnation and sol-gel process. The research focuses on the activity of ZnFe2O4 and how the activity of catalyst is affected by distribution ratio of active group and calcination temperature. It finds out that compared with single component catalyst, the activity of poly-component catalyst has been improved and is presented by XRD and BET. In the experiment of 2-ethylhexanol catalytic oxidation, the influence of some technic conditions on the activity of catalyst, such as the quantity of catalyst, reaction temperature and reaction time is examined. According to the statistics, the dynamics and mechanism in the process of 2-ethylhexoic acid production by catalytic oxidation is discussed preliminarily. The result shows that the mechanism is free radical reaction mechanism. Its activation energy is 93.4kJ/mol, which has been greatly reduced compared with the situation without catalyst.