نتایج جستجو برای: catalyst selectivity

تعداد نتایج: 86617  

Journal: :iranian journal of catalysis 2014
kobra nikoofar

ammonium monovanadate (nh4vo3) has been devoted as an efficient, commercially available, eco-friendly and reusable catalyst for the synthesis of bis(indolyl)methanes (bims), oxindole derivatives and also michael adducts of indoles at 50 °c under solvent-free conditions. the reusability of this solid acid catalyst in addition with its selectivity has also been examined.

Journal: :journal of physical & theoretical chemistry 2009
mahdi vadi najimeh astaneh

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...

2016
Jing Liu Jing He Luying Wang Rong Li Pan Chen Xin Rao Lihong Deng Long Rong Jiandu Lei

Nickel oxide (NiO) and phosphotungstic acid (PTA) supported on a ZIF-8 (NiO-PTA/ZIF-8) catalyst was first synthesized and it showed high activity and good selectivity for the hydrocracking of Jatropha oil. The catalyst was characterized by SEM, SEM-EDS, TEM, N2 adsorption, FT-IR, XRD and XPS. Compared with the NiO-PTA/Al2O3 catalyst, the selectivity of C15-C18 hydrocarbon increased over 36%, an...

Journal: :Nano letters 2016
Bunyarat Rungtaweevoranit Jayeon Baek Joyce R Araujo Braulio S Archanjo Kyung Min Choi Omar M Yaghi Gabor A Somorjai

We show that the activity and selectivity of Cu catalyst can be promoted by a Zr-based metal-organic framework (MOF), Zr6O4(OH)4(BDC)6 (BDC = 1,4-benzenedicarboxylate), UiO-66, to have a strong interaction with Zr oxide [Zr6O4(OH)4(-CO2)12] secondary building units (SBUs) of the MOF for CO2 hydrogenation to methanol. These interesting features are achieved by a catalyst composed of 18 nm single...

Journal: :iranian journal of oil & gas science and technology 2013
hamed rashidi touba hamoule mohammad reza khosravi nikou ahmad shariati

msu-s mesoporous catalyst with [sio2]/[al2o3] ratio of 55 was synthesized using tetrapropylammonium hydroxide (tpaoh) as a structure directing agent and hexadecyltrimethylammonium bromide (ctab) as a surfactant. the catalytic activity of the calcined sample was evaluated for the dehydration of methanol to dimethyl ether (dme) in a vertical fixed bed microreactor at a weight hurly space velocity...

Journal: :iranian journal of chemistry and chemical engineering (ijcce) 1991
m.m akbarnejad m. oskooie m. gharanfoli

fischer-tropsch catalysts with high activity and selectivity for olefins were produced using mordenite type sio2/al2o3= 12, 20, 28, 62 zeolite supported iron carbonyl compounds and were characterized by x-ray powder diffraction. the adsorptionof volatile fe(co)5 on the support surface was carried out under vacuum at room temperature. reduction les were monitored by vibrating sample magnetometer...

Journal: :Nanoscale 2016
Shunsuke Sakurai Maho Yamada Hiroko Sakurai Atsuko Sekiguchi Don N Futaba Kenji Hata

A method for the selective semiconducting single-walled carbon nanotube (SWCNT) growth over a continuous range from 67% to 98%, within the diameter range of 0.8-1.2 nm, by the use of a "catalyst conditioning process" prior to growth is reported. Continuous control revealed an inverse relationship between the selectivity and the yield as evidenced by a 1000-times difference in yield between the ...

2009
Ulla Létinois

The selective hydrogenation of dimedone (1) to the corresponding monoketone 2 over palladium and Amberlyst 15 ® is reported. The product is a synthetic building block for the fragrance and pharmaceutical industry. Advantages of the new catalytic procedure are the high catalyst activity and selectivity, less by-product formation, avoidance of the presence of acid, and consequently, less salt for...

2004
J. Christopher Brown Erdogan Gulari

We present the activities and selectivities of Pt/Al2O3-based catalysts in the production of hydrogen from methanol through catalytic decomposition. For the decomposition reaction, the Pt and Pd catalysts promoted by ceria exhibit similar activity reaching 100% conversion at 315 C. Promoting with ceria had a positive effect on activity and selectivity. Among all catalysts, the 9% Pt– 10% CeO2/A...

Journal: :Philosophical transactions. Series A, Mathematical, physical, and engineering sciences 2005
G J Hutchings

A brief commentary on the three papers presented in the session on 'industrial processes' is presented. In particular, emphasis is placed on the factors considered to be crucial for an industrial process, namely: catalyst activity, the selectivity of the overall catalysed reaction and the lifetime over which the performance is observed. Control of selectivity is viewed as being most important, ...

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