| Paraffin as byproduct of oil refining process, is a mixture of alkanes. It has the properties of stability, wide sources, low cost and large phase change thermal characteristics, are widely used in the phase change materials, paper surface coating. In order to prepare fine chemicals for further deep process, at present, mainly high temperature and high pressure cracker first used for preparing the cracking of short chain alkanes, but high energy consumption, equipment requirement and pyrolysis products of complex, etc.In order to further realize the paraffin greener preparation of short carbon alkane and its derivatives. In this paper, using photocatalytic technology to degrade n-dodecane of short carbon chain in paraffin, preliminary study the influence of the rate of photocatalytic reaction conditions three-phase reaction system. Choose chitin as the carrier, the preparation of TiO2, N-TiO2, N-TiO2, TiO2/Chitin and N-TiO2/Chitin four kinds of catalysts by Sol-vacuum distillation-gel. Verify visible light catalytic activity of catalysts as methyl orange to be degraded. The results of experimental study are as follows:(1) TiO2,N-TiO2,TiO2/Chitin and N-TiO2/Chitin four kinds of catalysts were prepared by Sol-vacuum distillation-gel and were characterized by the X-ray difrraction(XRD), Fourier infrared spectrometer(FTIR), Solid ultraviolet diffuse reflection instrument(UV-vis), New type of high resolution field emission scanning electron microscope (SEM), Thermogravimetric analyzer(TG). Comparative analysis showed that urea and chitin plays a big role in the nature of the catalyst, N-TiO2/Chitin, due to the effect of dispersion of the chitin, is smaller in crystal grain size. The influence of combination of urea and chitin in TiO2 lead to be broken of TiO2-and Ti-O-Ti keyboard. More oxygen hole were formed, chitin was incomplete ashing in form aspects of catalyst, with a block structure. The increase of specific surface area improve the adsorption capacity of catalyst. Response spectrum extending to visible light, it can use a wide wavelength range of light.(2)With methyl orange as substance to be degraded, butyl titanate and chitin mass ratio, calcining temperature, calcining time three factors effect on catalyst activity in the preparation process of catalyst were studied by single factor method. Through orthogonal experiment to determine the size of three factors effect on catalyst activity:calcination time than Ti/Chitin quality calcining temperature, and it is concluded that N-TiO2/Chitin, the optimal preparation conditions of catalysts:Ti/Chitin quality than to speak, calcination temperature is 400℃ and the calcination time is 2 h.(3)With methyl orange as substance to be degraded,single factor experiment and orthogonal experiment determine the optimum reaction conditions of photocatalytic degradation of methyl orange:pH of reaction system is 3, the amount of H2O2 is 5 ml,air flow rate is 250 L·h-1, catalyst dosage of 50mg.Under the optimal conditions, the residual rate of methyl orange eta is 2%.(4)With N-dodecane as substance to be degraded, single factor method analyse the air flow rate, the addition of H2O2 dosage, pH, water quantity of light catalytic during the degradation process. Through orthogonal test, the amount of H2O2, pH, water addition amount of the influence of three factors on the degradation rate was investigated:the amount of H2O2>pH of reaction system>the addition amount of water. And it is concluded that the optimal level of each factor is:pH of the reaction system is 4, addition amount of water is 20 ml, addition amount of H2O2 is 4ml.Under the optimal conditions, the degradation of dodecanoic rate was 43%.(5)Through the analysis of the catalytic reaction’s gas and oil phase-product:the product of the photocatalytic degradation of dodecanoic were mainly CO2,5-Decanone,dodecanoic acid,dodecan-2-one. |
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