| Alcohol oxidation is a hot issues in the field of organic synthesis at this stage of domestic and international. In the conventional oxidation process, most use many strong oxidant, because of their toxicity and the strong corrosion led to the production there are many security problem. With the modern chemical development, using of O2, H2O2 and other green, clean oxidant instead of the traditional role of oxidant in catalytic oxidation of alcohol become the focus of the green oxidation. Therefore developing high performance, low-cost, clean, recyclable and heterogeneous solid catalyst is the keys of current research. Because of widely used as 2-ethylhexanoic acid and representative, this study apply to the oxygen as the oxidant and self-made catalysts, obtained 2-ethylhexanoic acid at catalytic oxidation with 2-ethylhexanol.To 2-ethylhexanol conversion rate, yield and selection of 2-ethylhexanoic acid as the activity of catalyst evaluation. Preparation conditions of catalyst were optimized and the performance of different catalysts was investigated. Through the use of catalyst, reaction time and reaction temperature were researched on oxidation technology of 2-ethylhexanol.At the same time the stability of the catalyst and the reaction mechanism and kinetics were discussed preliminarily.In the experiment, with SiO2 as the carrier, a series of transition metal oxides catalysts were prepared by impregnation method. By 2-ethylhexanol Oxidation test, the three best active of the single-component catalyst were selected, Fe2O3/SiO2, Al2O3/SiO2, ZnO/SiO2.The effects of the loading amount and the temperature of calcination on the catalytic activity were investigated and the catalyst samples were characterized by means of XRD, BET, SEM on the surface structure of catalyst. The results showed, when the temperature of calcination was 500℃,4% loading of Fe2O3/SiO2 had better catalytic performance, the selectivity and yield of 2-ethyl-hexanoic acid could reach 55.14% and 22.41%, respectively.On the basis of single-component, we prepared multi-component catalyst and found that Fe2O3-ZnO and ZnO-CeO2 has synergistic effect,catalytic activity than the single-component catalyst has obviously improved. But the other two-component catalyst activity is lower. The results showed,6%Fe-4%Zn catalyst conversion rate of 2-ethylhexanol was 55.62%, the selectivity and yield of 2-ethylhexanoic acid were 63.66% and 35.41%.6%Zn-4%Ce catalyst conversion rate of 2-ethylhexanol was 52.83%, the selectivity and yield of 2-ethylhexanoic acid were 68.73% and 36.31%.The catalyst samples were characterized by means of XRD, BET, SEM and the relationship between surface structure and catalytic properties was analyzed.The process conditions, the amount of catalyst, reaction temperature and reaction time, on the impact on the Reaction results were investigated by 2-ethylhexanol to 2-ethylhexanoic acid. The optimum conditions of test:the amount was 4%, reaction temperature was12℃and reaction time was 7h.Recycling the catalyst and the stability of the catalyst was investigated. According to the data of test conditions, reaction kinetics and reaction mechanism were study preliminary in the test of 2-ethylhexanol to 2-ethylhexanoic acid. The results show that oxidation mechanism of 2-ethylhexanol to 2-ethylhexanoic acid was free radical reaction mechanism. The activation energy was 69.29kJ/mol, which was much lower activation energy under the conditions not use the catalyst... |
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