نتایج جستجو برای: catalyst activity
تعداد نتایج: 1169846 فیلتر نتایج به سال:
Poly (N-bromosuccinimide) (PNBS) as a mild, efficient, non-acidic, polymeric and heterogeneous catalyst was applied for simple conversion of epoxides into thiiranes by treatment with KSCN or (NH2)2CS at room temperature. Aliphatic and aromatic epoxides converted into their corresponding thiiranes under mild conditions. All reactions proceeded in short reaction times and afforded the correspondi...
Efficient and environmentally friendly syntheses of xanthenes derivatives by using γ-Fe2O3@HAP-Fe2+ NPs as a catalyst has been carried out. The catalyst can be readily isolated by using an external magnet and no obvious loss of activity was observed when the catalyst was reused in eight consecutive runs. The procedure has several advantages, such as economic...
High dispersion Pt nanoparticles supported on 2D Ti3C2X2 (X = OH, F) nanosheets are presented and electro-chemical measurements confirm that the Pt/Ti3C2X2 catalyst shows enhanced durability and improved ORR activity compared with the commercial Pt/C catalyst.
Accelerated deactivation of Co/Al2O3 catalysts in Fischer-Tropsch synthesis and the effect of Re and Ru as the catalytic promoters are reported. 15wt% Co/Al2O3 catalyst and 1wt% Ru and 1.4wt% Re promoted cobalt catalysts have been formulated and extensively characterized. The deactivation of the unpromoted cobalt catalyst and those promoted with ...
Bimetallic Pt-V supported by Gamma-alumina is used to observe the changes of nheptanewhen passed over this catalyst. The Pt concentration was kept constant at0.1wt% while the concentration of the vanadium was 0.5wt%. The activity andselectivity of catalyst have been determined under conditions at 450-500 degreescentigrade and 15-30 attn. The experimental results show that the addition of second...
Montmorillonite KSF has been used as an effective and non-toxic heterogeneous catalyst for one-pot synthesis of 5-substituted 1H-tetrazoles via [3+2] cycloaddition of sodium azide with a wide variety of nitriles. The reaction afforded high yields of the desired products in a short reaction time under mild reaction conditions. The catalyst can be recovered by simple filtration and reuse...
A new catalyst was prepared by promoting fly ash with hydrogen peroxide. The catalytic activity of H2O2 promoted fly ash (HPFA) was evaluated by synthesis 5(4H)-oxazolone and imidazolone derivatives under solvent free conditions. The possible mechanisms of synthesis reactions were also suggested. These proposed methods benefit in terms of low-cost catalyst, high yields, ease of workup, survival...
TiO(2) porous nanospheres on polypropylene (PP) films (TiO(2)/PP composite) are produced at ambient temperature. Particle/pore size match up is the key anchoring point to overcome the low affinity between hydrophilic materials and hydrophobic materials. With the hydrophilic TiO(2) catalyst evenly dispersed on a hydrophobic surface, the aqueous solution will selectively skip the substrate and we...
A convenient, simple and green process for the synthesis of 2,4,5-triaryl-1H-imidazole and 1,2,4,5-tetraaryl-1H-imidazole derivatives using snail shell, which is abundant in Morocco, as a catalyst in ethanol at 40 °C has been developed. Additionally, short reaction times, excellent yields, simple procedure and relative non-toxicity of the catalyst are other noteworthy advantages and make this m...
A convenient, simple and green process for the synthesis of 2,4,5-triaryl-1H-imidazole and 1,2,4,5-tetraaryl-1H-imidazole derivatives using snail shell, which is abundant in Morocco, as a catalyst in ethanol at 40 °C has been developed. Additionally, short reaction times, excellent yields, simple procedure and relative non-toxicity of the catalyst are other noteworthy advantages and make this m...
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