So <sub> 4 </ Sub> <sup> 2 - </ Sup> / M <sub> X </ Sub> O <sub> Y </ Sub> Solid Superacid Catalytic Low-carbon Alkyl Oxidative Coupling Reaction The Study

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 environmental friendly,play an important role in the chemical and petroleum industries.Slurry bubble column reactors are of considerable interest in industrial processes such as oxidation,hydrogenation of heavy oils,liquid phase methanol synthesis,chlorination,alkylation, wastewater treatment,and various biochemical processes,due to many advantages of these reactors, such as,low pressure drop in the reactor,excellent heat transfer characteristics resulting in stable reactor temperatures,and no diffusion limitations of catalyst particles,etc.At present,the demand of diesel is more and more large,so increasing the production of diesel has become inevitable.In addition,with the increasingly demands in environmental protection,CN improvement has become a necessity.So increasing diesel fuel production with high CN has become an important issue,in order to satisfy the need of energy and the requirements of environmental protection.In the paper,the tests were designed that low alkanes as the reactant in the oxidation atmosphere at room temperature and local atmospheric pressure using different catalysts of sulfated metal oxides.The aim to the study was for the development of the new synthetical methods to increase diesel fuel production with high CN,which was economical and environmentally friendly. The catalysts of one-component(SO₄^2-/TiO₂,SO₄^2-/SnO₂),two copies(SO₄^2-/TiO₂-SnO₂) and three groups(SFTSn and SMTSn) were prepared by co-precipitation method,and the catalysts were characterized by X-ray diffraction(XRD),Fourier transform infrared spectroscopy(FT-IR) and X-ray photoelectron spectroscopy(XPS).The analysis of each product was performed by gas chromatography-mass spectrometry(GC-MS) system.In one hand,the oxidation coupling of cyclohexane was studied at room temperature and atmospheric pressure with different oxidants(air and ozone) and different catalysts(SO₄^2-/TiO₂, SO₄^2-/SnO₂ and SO₄^2-/TiO₂-SnO₂) in slurry bed reactor.The product analysis showed that:the main long-chain alkanes were C₁₄～C₂₈ when SO₄^2-/TiO₂-SnO-2 was used as a catalyst,while the main long-chain alkanes were C₁₄～C₂₀ when SO₄^2-/TiO₂ or SO₄^2-/SnO₂ was used a catalyst.In addition, the selectivity of long-chain alkanes in air is higher than that of in ozone.The total selectivity of long-chain alkanes can reach ca.100%,when the reaction was carried out in air catalyzed by SO₄^2-/TiO₂-SnO₂.In the other hand,n-heptane was used as the reactant in air or ozone atmosphere at room temperature and atmospheric pressure using different sulfated tri-component metal oxides(SFTSn and SMTSn) in slurry bed reactor.The reaction time,catalyst and oxidant have some effect on the reaction.The relative selectivity(87.330%) of long linear alkane(C₁₂～C₂₈) from n-heptane reach the maximum when the reaction under SMTSn catalyst in flow air at 60 min.Diesel fuel with a high CN can be obtained from the above study of oxidative coupling of light alkanes,although the yield is not high,but the study of methods to increase diesel fuel production will open up a new way.