نتایج جستجو برای: chromium catalyst
تعداد نتایج: 66869 فیلتر نتایج به سال:
In the present research, the selective oxidation of lauryl alcohol to lauraldehyde was studied under liquid-liquid phase transfer conditions using potassium chromate (K2CrO4) as an oxidizing agent and tetrabutyl ammonium bromide (TBAB) as the phase transfer catalyst. Chromium (VI) reagents are used in these oxidations since the alcohols are selectively oxidized <e...
Chromium-vanadium (Cr-V) bimetallic catalysts are prepared by the introduction of vanadium into the Phillips catalyst which is one of the most significant industrial ethylene polymerization catalysts for tuning the Phillips catalyst performances and improving polyethylene properties. In the present work, titanium species were introduced into the fluorine-modified chromium-vanadium bimetallic ca...
The conversion of the cellulose into 5-HMF would experience three steps, cellulose to glycose, glycose to fructose and fructose to 5-HMF. Chloride ion can break down the hydrogen bond in cellucose, chromium can catalyze the isomerization of glycose to fructose, and the high temperature is helpful to cyclohydration of fructose to 5-HMF. In this paper, the sawdust has been directly degraded i...
A. General Introduction Among the transition metal ions of the 3d series, Cr takes a particular position because of its variability in oxidation state, coordination numbers and molecular structure.1,2 The elucidation of these Cr species on inorganic oxidic surfaces is a complex task, which is of fundamental importance to understanding the behavior of Cr in the environment, colloids, and Cr-base...
In this study, the zinc chromium ferrite magnetic nanoparticles ZnCrFeO4 are synthesized via sol-gel method and characterized by X-ray diffraction (XRD) analysis, Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM). The XRD analysis showed that ZnCrFeO4 has single-phase cubic structure. The synthesized ZnCrFeO4 has been used as an efficient catalyst for acetyl...
(Received: May 18, 2012; Accepted in Revised Form: February 4, 2013) Abstract: Direct oxidation of benzene to phenol in liquid phase in the medium of methanol, acetone, acetic acid and acetonitrile as a solvent over chromium catalyst supported on highly ordered nanoporous silica (Cr-LUS-1) by H O were examined. The best results obtained from methanol solvent with 20% yield and selectivity of 90...
High catalytic activity is found to be due the combination of a chromium catalyst with large pores (MIL-101(Cr)) aprotic solvents (γ-valerolactone−10% H2O).
Vanadium is an important metal used almost exclusively in ferrous and non-ferrous alloys due to its physicochemical and mechanical properties such as grain refinement, high tensile strength, hardness and fatigue resistance; it has a wide range of uses in the metallurgical and chemical sectors [1–3]. There are mainly three kinds of raw materials, bone coal, vanadium slag and waste vanadium catal...
Chromium oxide nanoparticles were synthesized by the reduction of potassium dichromate solution with Mukia Maderaspatana plant extract. In electrochemical methods, Cr2O3 nanoparticles were synthesized by two ways, using platinum (Pt) electrodes and K2Cr2O7 solution with H2SO4 as medium in the first case. And chromium doped platinum electrode (Pt/Cr) in presence of NaHCO3 solution in second case...
The chromium(I) dinitrogen complex [(i-Pr2Ph)2nacnacCr]2(μ-η(2):η(2)-N2) catalyzes the selective trimerization of ethylene to 1-hexene at ambient pressure and temperature, and in the absence of any cocatalyst. After the conversion of the substrate, the catalyst cleanly converts to another chromium(I) species, namely [(i-Pr2Ph)2nacnacCr]2(μ-η(2):η(2)-C2H4), which is not catalytically active. Bin...
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