Authors:Natasza Krawczyk, Stanisław Karski, and Izabela Witońska
interaction, which may occur on the surface of bimetallic supportedcatalysts, was not taken into account. Moreover, there are a lot of different factors which may influence the activity and selectivity of bimetallic systems based on palladium. Considering the
Authors:Brecht Egle, Juan Muñoz, Nerea Alonso, Wim De Borggraeve, Antonio de la Hoz, Angel Díaz-Ortiz, and Jesús Alcázar
The first example of an alkyl–aryl Negishi coupling in a practical, sustainable, and high-yielding process using a silica-supported catalyst in flow is described. Excellent conversions and good functional group compatibility were obtained under very mild conditions. Functionalized alkyl groups were also introduced to provide access to synthetically useful molecules and to demonstrate the versatility of the method. The scalability was assessed, and a throughput of 7.5 mmol/h of processed substrate was achieved. All crude products were free from phosphine derivatives and ready for use in subsequent reaction steps.
Authors:M. N. Ramsis, Ch. A. Philip, M. Abd El Khalik, and E. R. Souaya
CoO/Al2O3 catalysts containing amounts of cobalt ranging form 2 to 20% were prepared atpH 11 from neutral mesoporous alumina composed of γ-Al2O3 and poorly crystalline boehmite, and were then dried at 80‡C. X-ray diffraction, DTA and TG techniques were used to study the structural changes produced upon thermal treatment up to 700‡C.
SBA-15 materials were synthesized through the hydrothermal method. The SBA-15 prepared at the hydrothermal time of 24 h possessed
a higher surface area and a good hexagonal structure, so it was used as the catalytic support in this experiment. The base
metals (Cu, Co, Ni) coated on SBA-15 were prepared for toluene removal. The results revealed that the catalytic activity of
Cu/SBA-15 for toluene removal was about 70% at 250 °C, which was the best among the three catalysts. The modification of Cu/SBA-15
by adding different transition metals (Ce, Co, Ni, Mn) to improve the removal efficiency of toluene and NO was also investigated
in this study. The results indicate that the catalytic activity of Mn–Cu/SBA-15 for toluene removal was about 100% at 250 °C.
The toluene as a reductant on the removal of NO was also determined. Furthermore, the catalytic activity of Mn–Cu/SBA-15 for
NO removal can reach about 70% at 300 °C when toluene is used as reductant.
Authors:V. Braga, F. Garcia, J. Dias, and Sílvia Dias
Nb2O5 supported on SiO2-Al2O3 were prepared with a wide loading range (2, 5, 10, 15, 20 and 25 mass%) and analyzed by simultaneous thermogravimetric (TG)
and differential thermal analysis (DTA). The materials presented a phase transition close to 1364°C. This phase transition
was studied by XRD, FTIR and Raman spectroscopy. Amixture of orthorhombic (T) andmonoclinic (H andM) crystalline phases was
evidenced in the supported samples, which is coverage dependent, in contrast to the formation of only the monoclinic phase
(H and M) when pure Nb2O5 is heated under the same conditions. These results indicate the stabilization of Nb2O5 on silica-alumina surface.
Authors:Pawel Mierczynski, Tomasz P. Maniecki, Waldemar Maniukiewicz, and Wojciech K. Jozwiak
supportedcatalysts were dried at 120 °C and finally calcined for 4 h in air at 400 °C. The samples of monoxide supports—Al 2 O 3 , Cr 2 O 3 —were prepared by an analogous preparation procedure and calcined at 400 °C. As a reference, bimetallic Au
Continuous-flow hydrogenation of aromatic nitro compounds was successfully performed by using polysilane-supported palladium catalysts to afford the corresponding amino compounds in high yields. Productivity was high, and a wide variety of nitro compounds were applicable under the continuous-flow conditions. It is noted that no leaching of palladium was observed by inductively coupled plasma analysis.
supportedcatalysts as compared to the support is expected. It is observed from the table that there is a drastic increase in the surface area of 20%-PW 11 O 39 /ZrO 2 as compared to that of 20%-PW 12 O 40 /ZrO 2 indicating higher dispersion of PW 11 O 39
, 8 ]. Several types of supporting materials have been used for the immobilization of metal complexes [ 9 , 10 ]. Insoluble metal complex supportedcatalysts usually face the problem of metal leaching [ 11 ]. Particularly, our attention has been
The catalytic activity of the supportedcatalysts MPs–PVI/SiO 2
20 ml of ethyl benzene and 15–25 μmol of the solid catalysts (CoTPP–PVI/SiO 2 , Fe TPP–PVI/SiO 2 , MnTPP–PVI/SiO 2 , CoTNPP–PVI/SiO 2 or CoTClPP–PVI/SiO 2 ) were added into a