Study On The Synthesis Of Naphthol By Naphthalene Hydroxylation

Naphthol is an important organic raw material, and is mainly used for coatings, spices, rubber, plasticizers and pesticides. Currently, the main method is sulfonated synthesis, of which the drawback is a serious pollutant emissions and a long process flow. Therefore, the development of green economy catalyst and synthesis process has important practical meanings.In this thesis, supported metal catalysts MCM-41 molecular sieve, catalyst and monomer heteropolyacid supported heteropoly acid zeolite catalysts MCM-41 were prepared, and modification of MCM-41 zeolite catalytic naphthalene naphthol hydroxylation reaction were studied. Besides, the thesis also investigated the influence of temperature, time, ratio of reactants, the active ingredient load and other factors on the reaction. The catalysts were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM) and nitrogen adsorption specific surface area tester, and the reaction products were analyzed by thin layer chromatography plates (TLC). The results showed that:(1) MCM-41 supported heteropolyacid catalytic molecular has the best performance, and the optimal reaction conditions are as follows:the heteropolyacid H4PMo11VO40 loading of 7.5%. Under these conditions, the conversion was 33.84% naphthalene, the selectivity of 1-naphthol was 45.2%, selectivity of 2-naphthol 10.8%. (2) Modified MCM-41 can better maintain the MCM-41 structure. (3) The influence of reaction conditions were investiged with H4PM011VO40 heteropoly acid as catalyst. As temperatures rise, naphthalene conversion rate and selectivity of naphthol will rise, and at the temperature of about 65℃, the conversion rate of naphthalene reached a maximum of 27.15%, the selectivity of naphthol 46%. With the increase of reaction time, the conversion and selectivity naphthol naphthalene increased, and the naphthalene conversion rate changed smally after 6 h, 1-naphthol selective after reaching 8 h,2-naphthol selective held steady. With the increase of the content of hydrogen peroxide solution, naphthalene conversion and selectivity increased. With the increase of catalyst, naphthalene conversion rate and selectivity of naphthol increased significantly. Heteropoly acid-MCM-41 molecular sieve catalyst has great influence on the naphthalene hydroxylation selectivity and the yield of naphthol, and containing no heteropoly acid vanadium-MCM-41 of naphthalene can greatly improved conversion and naphthol selectivity.