نتایج جستجو برای: catalyst selectivity
تعداد نتایج: 86617 فیلتر نتایج به سال:
an extensive study of higher alcohol synthesis (has) from synthesis gas using cobalt (co) promoted alkalized mos2 catalysts supported on carbon nanotubes (cnts) is reported. up to 5wt.% of co is added to the 15wt.% mo-wt.%k/ cnts by incipient wetness impregnation method. most of the metal particles were homogeneously distributed inside the tubes and the rest on the outer surface of the cnts. t...
Bismuth plays important roles in promoting the oxidation of alcohols towards high-valueadded chemicals over a noble metal loading catalyst. Herein, Mg–Al hydrotalcite-supported platinum–bismuth nanoparticles (Pt–Bi/HT) were prepared by the co-impregnation method and used in the selective oxidation of glycerol towards dihydroxyacetone (DHA). The incorporation of Bi species into Pt/HT significant...
The selective oxidation of methoxy/methyl-substituted arenes to the corresponding benzoquinones has been first realized using aqueous hydrogen peroxide as a green oxidant, acid tetrabutylammonium salts of the γ-Keggin divanadium-substituted phosphotungstate [γ-PW10O38V2(μ-O)2]5- (I) as a catalyst, and MeCN as a solvent. The presence of the dioxovanadium core in the catalyst is crucial for the c...
Catalytic synthesis can be achieved by using either homogeneous or heterogeneous organometallic complexes, or homogeneous enzymatic biocatalysts. However, each of these methods offers advantages and disadvantages that must be balanced cautiously. Homogeneously catalyzed reactions are highly efficient in terms of selectivity (i.e. regioselectivity, enantiomeric excesses) and reaction rates, due ...
In pilot-plant tests, the linolenate content of soybean oil was reduced to less than 1% without increasing the saturates, by hydrogenation to an IV of about 115 with an active copper-chromite catalyst. The linolenate-linoleate selectivity ratio (KLe/KLo ) was from 9 to 12. Several commercial copper-chromite catalysts were used in hydrogenation tests. The activities of four of five commercial ca...
This paper describes a computational study of the partial oxidation of ethane to ethylene in a shortcontact-time reactor (SCTR), using a two-dimensional computational fluid dynamics model with full heat and mass transport. Detailed heterogeneous and homogeneous chemical kinetic mechanisms are employed to describe the chemistry. Emphasis is placed on simulating recent experiments in which the pl...
Coupling with robust surfaces is a promising approach to improve the stability and recyclability of highly active molecular catalysts. This study builds on our prior success to deposit a Co(iii) cyclam complex, where cyclam is 1,4,8,11-tetraazacyclotetradecane, on mesoporous silica via a microwave-assisted process. The Co(iii) complex was successfully deposited on the silica surface through rea...
Silicoaluminophosphate (SAPO-34) molecular sieve doped with transition metals, Mn and Ni, with different molar ratios (Mn/Ni=0.33, 3) were investigated for their activity, selectivity and lifetime in biomethanol to olefins reaction. MnNiAPSO-34 nanostructured catalyst was synthesized by hydrothermal method and addition of metals was carried out by isomorphous substitution into the crystalline f...
Dehydroaromatization of methane (DHAM) under non oxidative condition was studied over tungsten loaded HZSM-5 catalysts to produce aromatic hydrocarbons. The catalysts were prepared by impregnation method using different conditions: in neutral and acidified solution. The activity of W/HZSM-5 prepared by neutral solution and W-H2SO4/HZSM-5 prepared in acidified condition were compared. The result...
In this study, Mn (III) salen complex was synthesized and immobilized onto the graphene oxide, which is modified by 3-chloropropyltrimethoxy silane. Heterogeneous catalyst was characterized by X-ray diffraction, transmission electron microscopy, thermogravimetric analysis, fourier transform infrared spectra, nitrogen adsorption−desorption isotherm and atomic absorption spectroscopy. The catalyt...
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