Solid Superacid Catalytic Alkylation Of Synthetic Diesel Fractions

With the development of the industry in recent years, people focus a major concern on the problem of environment and energy. At the background of saving natural resources and sustainable development, the production of fuel demands cleaner and more environmental friendly refining process and catalyst technologies to control industrial production. As a major fuel, diesel oil applies to a wide range of transportation, agricultural machinery and other fields for its excellent combustion efficiency. And also with the national economic development, especially in the transport industry and automotive industry, diesel demand is bound to increase then; the study of diesel substitutes cannot be ignored. Therefore, we prepared a series of solid super acid catalysts and studied their catalytic properties on coupling reaction at room temperature and atmospheric pressure. It has a certain reference value for further development and application of this type of solid acid catalyst. The results show that the main products were linear alkanes, besides a little branched alkanes, cycloalkane, and oxygen compounds were also detected. These diesels like fractions have some reference value to ease the relative surplus of gasoline and diesel fuel shortage for the time being. Except that, this approach not only has a simple operation process, but also free from emission of sulfur and nitrogen compounds, in line with the requirements of green chemistry.In the first part of dissertation, the basic knowledge of status of diesel progress, identification of the scope of diesel, applications of synthetic diesel and the solid super acids were introduced and reviewed. It simply analyzed the supply and demand situation of diesel. The composition of diesel, scope and Cetane Number were emphasized. In addition, the basic knowledge of solid super acid can also be expatiated seriously, including classification, model of acidic center, preparation method, the characterization of acid strength, application and the problem at present.Based on the understanding of green chemistry and current development, the second part designed the experimental method, simulated produced a slurry reactor, and introduced in details for the coupling reaction and analytic methods of products.Finally, the coupling reaction of n-hexane was carried out in the fluid phase by using different metal modified solid super acids, the different solid super acids based on iron prepared with different methods and different solid super acids respectively. The effects of type of catalyst, preparation methods and modifier on the reaction were also investigated. The ultraviolet spectrophotometer was adopted to track the course of the reactions convenient for controlling. The Fourier transform infrared spectrometer (IR), power X-ray diffraction (XRD), scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) had been introduced to characterize catalysts for understanding the nature of catalysts, metal valence changes and enriching the experiment data. Gas chromatography/ mass Spectrometry (GC/MS) were employed to test the final product to give the concentration and structure information, and it can be concluded from the analysts that the effect of molybdenum modified solid super acids catalysts were better than that of the other metal modified solid super acids, the molybdenum modified iron solid super acids catalysts treated by ultrasonic were better than untreated catalysts, composite solid super acids were better than single solid super acids. The products were also analyzed in detail. They are all linear alkanes from C₁₁ to C₂₈, all of them can be used as diesel distillates.There was little report in literature about this method and main products. The synthesis procession conducted in our research was simple. It can be performed under mild conditions with more convenient operation, short reaction time, and lower energy consumption, avoiding the high pressure and temperature. Furthermore, the diesel fraction produced by this method was free from sulfur and nitrogen. After all, it was a green environment-friendly liquid fuel.