نتایج جستجو برای: catalyst selectivity
تعداد نتایج: 86617 فیلتر نتایج به سال:
1-butyl-3-methyl imidazolinium hydroxide ionic liquid (BMIm[OH]) is loaded on commercial low surface area Pd-Ag/α-Al2O3 solid catalyst to enhance higher selectivity of acetylene partial hydrogenation. Different experimental techniques such as atomic absorption spectroscopy, surface area measurement and gas chromatography have been utilized to characterize chemical, structural and catalytic pro...
Manganese metal-organic framework (Mn-MOF) containing Mn2+ ions, benzenetricarboxylic acid (BTC) and N,N-dimethylformamid (DMF) was prepared and used as catalyst for oxidation of alkenes such as 1,1-diphenylethylene, trans-stilbene, cyclohexene, norbornene, styrene and cyclooctene to epoxides with 33-92% conversion and 75-100% selectivity and oxidation of alkanes such as fluorene, adamantane, e...
Oxidation of ethylene to ethylene oxide over silver catalyst and selenium modified catalyst has been studied by continuous flow and pulse techniques over the temperature range of 230-280 °C. The results are discussed in terms of reaction mechanisms proposed by others, rejecting mechanisms which involve peroxide formation. It has been shown that not only selectivity towards ethylene oxide pr...
Hydrothermally synthesized high silica borosilicates with the MFI structure was subjected to several characterization techniques. The effect of boron on the structure and acidity of HZSM-5 catalyst were studied by XRD, SEM, N2 adsorption, solid state NMR, NH3-TPD. It was confirmed that boron had entered the framework in the boron samples. The results also revealed that strong acidity was weaken...
We describe mechanistic investigations of a catalyst (1) that leads to selective epoxidation of farnesol at the 6,7-position, remote from the hydroxyl directing group. The experimental lineage of peptide 1 and a number of resin-bound peptide analogues were examined to reveal the importance of four N-terminal residues. We examined the selectivity of truncated analogues to find that a trimer is s...
Transition metal catalysis plays an important role in both industry and in academia where selectivity, activity and stability are crucial parameters to control. Next to changing the structure of the ligand, introducing a confined space as a second coordination sphere around a metal catalyst has recently been shown to be a viable method to induce new selectivity and activity in transition metal ...
Abstraet--Jordanian natural kaolin and bentonite show good catalytic activity towards debutylating 2tert-butylphenol, and varying debutylation vs. isomerization selectivity after acid activation. The resulting catalytic activity of these samples is dependent on the acid employed for activation; the samples treated with acetic acid showed relatively low conversions, whereas those treated with hy...
bis-(l-tyrosinato)copper(ii) was reacted with 3-(chloropropyl)-trimethoxysilane functionalized silica that has infused magnetite to yield a magnetically separable catalyst in which the copper carboxylate is covalently linked to the silica matrix through the silane linkage. the immobilized catalyst has been characterized by spectroscopic studies (such as ft-ir, epr, magnetic measurement, sem) an...
The activity and selectivity of aluminaand magnesia-supported vanadia for propane oxidative dehydrogenation can be enhanced by can be enhanced by interactions of vanadia with molydena for the alumina-supported catalyst and by phosphorous doping for the magnesia-supported catalyst.
A new microporous metal-organic framework compound featuring chiral (salen)Mn struts is highly effective as an asymmetric catalyst for olefin epoxidation, yielding enantiomeric excesses that rival those of the free molecular analogue. Framework confinement of the manganese salen entity enhances catalyst stability, imparts substrate size selectivity, and permits catalyst separation and reuse.
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