Superacid Catalytic Zirconium Metal Modified Under Oxidizing Atmosphere At Room Temperature Oxidation Of Cyclohexane

In recent years, environmental problem has drawn increasing attention. Solid acid catalyst instead of liquid acid is one of the most important ways with the direction of the development of green chemistry. The SO₄^2-/M_xO_y solid acid has been proved to be a useful and active catalyst in many kinds of important catalytic reaction of alkane. Furthermore, the kind of catalyst, that has several advantages such as easy separation, good reusability of the catalyst, non corrosion to the reactor and usage of environmental friendly, play an important role in the chemical and petroleum industries.From the prevenient studies by other researchers, many large volume applications based on SO₄^2-/M_xO_y solid acid are reported in the literature, especially in the petroleum industry for alkylation and isomerization reactions in the reductive ambience. In the contrast, the effect of the kind of catalysts on oxidation of alkane under mild condition has been paid little attention. The content of this subject study is presented on the basis of the status. In the thesis, SO₄^2-/ZrO₂-CuO, SO₄^2-/ZrO₂-Co₂O₃ and SO₄^2-/ZrO₂-V₂O₅ were synthesized and their application in the oxidation of cyclohexane under mild condition (room temperature and atmospheric pressure) was investigated. The aim to the study was for the development of the synthetical methods to oxygenous ramification, which was economical and environmentally friendly.In the paper, the catalytical activity to the samples of SO₄^2-/ZrO₂-CuO, SO₄^2-/ZrO₂-Co₂O₃ and the sample of SO₄^2-/ZrO₂-V₂O₅, which prepared by precipitation method and precipitation-impregnation method, respectively, were investigated in the oxidation of cyclohexane under mild condition (room temperature, air as the oxidant). Qualitative and quantitative analysis of each product was performed by UV-vis spectra and gas chromatography-mass spectrometry (GC-MS) system. The results show that, compared to non-metal oxide modified sulfate zirconia, the yield of ester obviously increased at overall products when the metal oxide CuO and Co₂O₃ were added to solid acid. The main products to the sample of SO₄^2-/ZrO₂-CuO were dibutyl phthalate. And another kind of ester, except for phthalate ester, named cyclohexyl triclecyl oxalate, was found in the products solvent to the sample of SO₄^2-/ZrO₂-Co₂O₃. But the yield of the ester with SO₄^2-/ZrO₂-Co₂O₃ was lower than that of SO₄^2-/ZrO₂-CuO. The one-step esterification reaction, that offers several advantages such as economical and environmental friendly, is necessary for ester chemosynthesis industry from the environment standpoint. In the case of SO₄^2-/ZrO₂-V₂O₅, the main products were long line alkane, and the content of ester in the overall products was low. The realization of direct transformation from cyclohexane into long line alkane was very significant, not only for the production of environmentally friendly diesel oil in high octane number, but also for the research of the petroleum forming process. Otherwise, the three kinds of catalysts were well characterized in this work. The catalyst before the reaction was characterized by means of X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). XRD analysis shows that after the high-temperature burning, catalyst ZrO₂ changed from amorphous to crystalline quartet, formed an active site and had strong catalytic activity. CuO Co₂O₃ and V₂O₅ was in the highly fragmented state in catalyst. Solid acid catalyst can not be product without burning. IR spectra show the existence of O=S=O, acid center and catalyst which is easy-absorbent. The catalysts after the reaction was investigated by means of X-ray photoelectron spectroscopy (XPS), the result displayed that the binding energies of all of the elements are almost unchanged after the reaction, except C element, indicating the stability of the structure of the modified catalyst and also suggesting that the solid acid may be recycling applied after appropriate activation.