He’an Luo

H3PW12O40 synergized with MCM-41 for the catalytic nitration of benzene with NO2 to nitrobenzene

Developing a new environmentally friendly process for benzene nitration to nitrobenzene has been highly desirable for a long time. In this work, NO2 was used as a nitration agent to replace traditional nitric acid, and different mesoporous SiO2 and their supported heteropoly acid (salt) were employed to catalyze benzene nitration to nitrobenzene. Several typical catalysts were characterized using XRD, BET and FT-IR, and the acid amounts of the various catalysts were determined. The effects of various factors such as different catalysts, the molar ratio of benzene to NO2, reaction temperature, reaction time, HPW loading, the acid amounts of the catalyst and the reuse of the catalyst on the nitration reaction have also been systematically examined. The results indicate that the supported HPW/MCM-41 catalysts exhibit a remarkably synergistic catalytic performance on the nitration reaction of benzene to nitrobenzene. In particular, the 50%HPW/MCM-41 catalyst gives the best results with 73.4% benzene conversion and 98.8% selectivity to nitrobenzene under the optimal reaction conditions. Moreover, the mesoporous structure of MCM-41 was retained under the high loading of HPW. The possible reaction mechanism for the nitration reaction of benzene with NO2 over HPW/MCM-41 is suggested in the present work. This method provides a promising strategy for the preparation of nitro-aromatic compounds from a catalytic nitration reaction by using NO2 as the nitration reagent.

Liquid phase hydrogenation of adiponitrile over amorphous alloy nickel catalyst

Supported Ni–B and Ni–B–K amorphous alloy catalysts were prepared by chemical reduction method and characterized by nitrogen adsorption–desorption, power X-ray diffraction, selected area electron diffraction, and scanning electron microscopy. The prepared catalysts were tested in liquid phase hydrogenation of adiponitrile in the absence of ammonia under mild condition. Ni–B–K/SiO2 exhibited high activity and selectivity toward 6-aminocapronitrile and 1,6-hexanediamine.

Hydrophilicity Modification of MCM-41 With Zirconia and Supported Ruthenium-Lanthanum for Benzene Hydrogenation to Cyclohexene

Zirconia modified mesoporous molecular sieve MCM-41 supports were prepared by hydrothermal synthesis method, in situ synthesis method and precipitation method. Ruthenium and lanthanum supported on MCM-41 and zirconia modified MCM-41 catalysts were prepared via two solvents impregnation method. The catalysts were characterized by X-ray diffraction, transmission electron microscopy, nitrogen adsorption-desorption, and water/benzene static adsorptions techniques. It has been found that Ru-La supported on MCM-41 modified with zirconia by hydrothermal synthesis method (Ru-La/ZrO2-MCM-41-HS) leads to the biggest increase of the hydrophilicity. Ru-La/ZrO2-MCM-41-HS catalyst with the highest hydrophilicity shows the best performance in liquid phase hydrogenation of benzene to cyclohexene.

Nitrocyclohexane hydrogenation to ε-caprolactam over Pd/C and 2,4,6-trichloro-[1,3,5]-triazine in N,N-dimethylformamide

A new composite catalytic system of Pd/C, 2,4,6-trichloro-[1,3,5]-triazine and N,N-dimethylformamide was investigated in nitrocyclohexane hydrogenation to ε-caprolactam. The Pd/C catalyst was prepared by the incipient impregnation method and characterized by BET, N2 adsorption–desorption, XRD, TEM and H2 chemisorption. The results indicate that 2,4,6-trichloro-[1,3,5]-triazine plays a key role in one step synthesis of ε-caprolactam from nitrocyclohexane hydrogenation. Besides ε-caprolactam, the products include cyclohexanone oxime, cyclohexamine, cyclohexanone and cyclohexanol. A possible mechanism for nitrocyclohexane hydrogenation in 2,4,6-trichloro-[1,3,5]-triazine and N,N-dimethylformamide complex was proposed.

Metal salts with highly electronegative cations as efficient catalysts for the liquid-phase nitration of benzene by NO 2 to nitrobenzene

Metal salts with highly electronegative cations have been used to effectively catalyze the liquid-phase nitration of benzene by NO2 to nitrobenzene under solvent-free conditions. Several salts including FeCl3, ZrCl4, AlCl3, CuCl2, NiCl2, ZnCl2, MnCl2, Fe(NO3)3∙9H2O, Bi (NO3)3∙5H2O, Zr(NO3)4∙5H2O, Cu(NO3)2∙6H2O, Ni (NO3)2∙6H2O, Zn(NO3)2∙6H2O, Fe2(SO4)3, and CuSO4 were examined and anhydrous FeCl3 exhibited the best catalytic performance under the optimal reaction conditions. The benzene conversion and selectivity to nitrobenzene were both over 99%. In addition, it was determined that the metal counterion and the presence of water hydrates in the salt affects the catalytic activity. This method is simple and efficient and may have potential industrial application prospects.

Different Crystal Form Titania Supported Ruthenium Nanoparticles for Liquid Phase Hydrodeoxygenation of Guaiacol

Titania supported Ruthenium-based catalysts were prepared for liquid phase hydrodeoxygenation of guaiacol to cyclohexanol. The catalytic performance is affected by the different crystal forms of titania supports. Anatase and rutile titania supported catalyst 5%Ru/a-r-TiO2 presents higher BET surface area, better dispersion of Ru particles with smaller particle size of 3-4 nm, more acidic centers, and more Ruδ+ located at the boundary between anatase titania and rutile titania. Hence, 5%Ru/a-r-TiO2 gives the best catalytic performance of 95.33% conversion of guaiacol and 79.23% selectivity to cyclohexanol, other products mainly include cyclohexane, benzene, cyclohexanone and 1,2-cyclohexanediol. Based on the results of this work, the possible reaction path for guaiacol hydrodeoxygenation was proposed.