Acetonitrile physicochemical properties

Dynamic light-scattering experiments or the analysis of some physicochemical properties have shown that finite amounts of formamide, A-methylformamide, AA-dimethyl-formamide, ethylene glycol, glycerol, acetonitrile, methanol, and 1,2 propanediol can be entrapped within the micellar core of AOT-reversed micelles [33-36], The encapsulation of formamide and A-methylformamide nanoclusters in AOT-reversed micelles involves a significant breakage of the H-bond network characterizing their structure in the pure state. Moreover, from solvation dynamics measurements it was deduced that the intramicellar formamide is nearly completely immobilized [34,35],... 

Chromium zeolites are recognised to possess, at least at the laboratory scale, notable catalytic properties like in ethylene polymerization, oxidation of hydrocarbons, cracking of cumene, disproportionation of n-heptane, and thermolysis of H20 [ 1 ]. Several factors may have an effect on the catalytic activity of the chromium catalysts, such as the oxidation state, the structure (amorphous or crystalline, mono/di-chromate or polychromates, oxides, etc.) and the interaction of the chromium species with the support which depends essentially on the catalysts preparation method. They are ruled principally by several parameters such as the metal loading, the support characteristics, and the nature of the post-treatment (calcination, reduction, etc.). The nature of metal precursor is a parameter which can affect the predominance of chromium species in zeolite. In the case of solid-state exchange, the exchange process initially takes place at the solid- solid interface between the precursor salt and zeolite grains, and the success of the exchange depends on the type of interactions developed [2]. The aim of this work is to study the effect of the chromium precursor on the physicochemical properties of chromium loaded ZSM-5 catalysts and their catalytic performance in ethylene ammoxidation to acetonitrile. 

The structures (geometrical and electronic) and physicochemical properties of the LTMO complexes are only now adequately established to facilitate interpretable reactivity studies. Parallel investigations are currently being conducted in both aqueous media using alkali metal salts of the complexes and in organic media (e.g., acetonitrile) using tetralkylammonium salts of the complexes. Thus far oxo transfer from the Pd-oxo and Au-oxo complexes to multiple organic substrates has been documented. This work will be reported subsequently. 

Tetrakis(acetato)ditungsten(II) is a very air-sensitive, bright yellow, diamagnetic solid. It is moderately soluble in THF and acetonitrile but solutions in the latter solvent decompose after several hours. The 360 MHz XH NMR spectrum (in THF-d8) consists of a single methyl resonance at S 2.91. The mass spectrum (solid probe, electron impact, 40-70-eV ionizing voltage) shows the parent ion multiplet at m/e 604. Other spectroscopic data and physicochemical properties are described in the literature.8... 

Laccaic acids have two or three carboxyl groups, five or six hydroxyl groups, and/or one amino group, and are freely soluble in water, but only shghtly soluble in organic solvents such as chloroform and ethyl acetate. Based on these physicochemical properties of laccaic acids, we selected a two-phase solvent system composed of tert-hutyl methyl ether/n-butanol/acetonitrile/water, which has been frequently used as the solvent system for the separation of hydrophihc... 

Surface plasmon resonance (SPR) provides thickness information at the elec-trode/solution interfaces on a nanometer level. Therefore, SPR has recently been recognized as an alternative method to obtain information concerning the material transport. Bailey et al. [34] examined the reductive desorption of C18SH SAMs in 0.1 M TEAP/acetonitrile using an SPR/QCM combined system for the simultaneous acquisition of both data. The two techniques gave nearly identical results for the desorption kinetics of the film prepared by a 465-min immersion of the electrode in a thiol solution. For the film prepared by a 160-min immersion, however, the results were significantly different from each other (Fig. 3). This was considered to be due to the difference in their physicochemical properties, on which both techniques are based. When the film is desorbed, namely, the C18S-rich layer in... 

Due to the versatility of HSCCC and CPC instmments, various solvent systems have been tested for the purification of polyphenols according to their stmcture, polarity, or other physicochemical properties. As illustrated in Fig. 70.2, the solvent system composed of -hexane, ethyl acetate, methanol, and water is by far the most commonly used solvent system for the purification of polyphenols despite the large number of other possibilities. Generally, this solvent system (related to the Arizona liquid system) is particularly adapted for the purification of polyphenols with moderate polarity [38]. As shown in Table 70.1 and Fig. 70.2, -hexane can be replaced by -heptane or petroleum ether, and methanol can be replaced by acetonitrile or ethanol. The proportions of each solvent can vary greatly with... 

It was recognized a decade ago that nitrosahve deamination of G by acidified nitrite led to the formation of two products xanthine and oxanine (O) [110, 111]. Shuker et al. also observed the formation of O base in reactions of 2 -deoxyribonucleotides and calf thymus DNA with millimolar concentrations of the mutagenic nitrosating agent l-nitrosoindole-3-acetonitrile under weakly buffered conditions (0.5 mM Tris) [112, 113]. These observations have led several groups to define the physicochemical and biological properties of O [96, 114—133],... 

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