Argon atmospheric concentration

M f-BuLi in pentane (14.7 mL, 22 mmol) was added dropwise to a stirred solution of 8 (R = /-Bu 2.63 g, 10 mmol) in anhyd THF (40 mL) at — 80C under an argon atmosphere, and the mixture was stirred at — 80 C for 1 h. After the addition of sublimed sulfur powder (320 mg, 10 mmol), the mixture was allowed to warm to rt over a 2-h period with stirring, and then EtOH (10 mL) was added. The mixture was heated at 55 C with stirring for 2-4 h, poured into ice-water (lOOmL), and then the whole was extracted with Et20 (3 x lOOmL). The combined extract was washed with brine, dried (MgS04), and concentrated in vacuo, and the residue was chromatographed (silica gel, hexane) yield 0.54 g (25%). 

Coelenterazine analogues are easily soluble in methanol like coelenterazine. When methanol is used, however, the methanol concentration in the regeneration mixture should not exceed 5%. If the use of methanol must be avoided, dissolve the coelenterazine analogue in water with the help of a trace amount of 1M NaOH. However, coe-lenterazines in alkaline condition are extremely unstable. Therefore, the solution must be made rapidly in argon atmosphere and added at once to the regeneration mixture containing apoaequorin. 

NB. Mixed solvent systems are shown as e.g. acn-aq (0.01 M) where the number in parentheses indicates the concentration of the lesser constituent ITO-Indium/tin oxide-coated glass, Ar- Solutions purged with argon, Ar atm - Experiment performed under an argon atmosphere, N2 atm - Experiment performed under a nitrogen atmosphere b All potentials are measured vs. SCE unless otherwise stated ... 

The paper electrophoresis experiments carried out to study the mobility of polynuclear technetium clusters in aqueous solutions of HX of varying acidity, as a mobile phase, showed that these clusters were also characterized by reversible reactions such as (5) without leading to destruction of M-M bonds. On the other hand, an autoclave recrystallization of the polynuclear clusters at 200-220°C in an atmosphere of argon from concentrated solutions of HX led to a partial destruction of M-M bonds and the formation of binuclear complexes [Tc2X8]3 and [Tc,X6]2. This indirectly shows that reactions (6) and (7), leading to the destruction of M-M bonds, are likely in solutions of polynuclear clusters [15]. 

The regeneration of nitroxyl radical from the product of the reaction of nitroxyl radical with the alkyl macroradical was proved in the following experiments [51]. The nitroxyl radical and initiator (dicumyl peroxide) were introduced in a PP powder and this sample was heated to T= 387 K in an argon atmosphere. The concentration of nitroxyl radical was monitored by the EPR technique. The nitroxyl radical was consumed in PP with the rate of free radical generation by the initiator (see Figure 19.3). Dioxygen was introduced in the reactor after the nitroxyl radical was consumed. The generation of peroxyl radicals induced the formation of nitroxyl radicals from the adduct of the nitroxyl radical with the PP macroradical. 

Diethyl phosphorochloridite (0.714 ml, 5 mmol) was added dropwise to a stirred solution of 2,5-dimethoxytetrahydrofuran (0.65 ml, 5 mmol) in methylene chloride at 0°C under an argon atmosphere. The solution was then stirred at room temperature for 12 h, after which the solution was concentrated under reduced pressure and the residue subjected to Kugelrohr distillation (120°C/0.03 torr). There was in this manner isolated the pure diethyl 5-methoxytetrahydrofuran-2-ylphosphonate (0.475 g, 48%) as a colorless oil. 

Preparation of n-nonanoylzirconocene chloride and Yb(OTf)3/TMSOTf (1 1 (-catalyzed reaction with N-benzylideneaniline (Scheme 5.15) 1-Octene (2.0 mmol) was treated with [Cp2Zr(H)Cl] (1.3 mmol) in CH2C12 (4 mL) at ambient temperature for 0.5 h under argon atmosphere, and then the mixture was further stirred under an atmosphere of CO (1 atm) at ambient temperature for 2 h. The solution was subsequently concentrated to dryness in vacuo and the residue was redissolved in THF (6 mL). 

To a solution of thioglycoside (1.0 equiv), 1-benzenesulfinyl piperidine (1.0 equiv), TTBP (2.0 equiv), and freshly activated 3 A powdered molecular sieves in dichloromethane (25.0 ml mmol-1) was added trifluoromethanesulfonic anhydride (1.1 equiv) at —60 °C under an argon atmosphere. The reaction mixture was stirred for 5 min, after that a solution of the glycosyl acceptor (1.5 equiv) in dichloromethane (4.0 ml mmol-1) was added. The reaction mixture was stirred at — 60 °C for 2 min, after that it was slowly warmed to room temperature and quenched by the addition of saturated aqueous NaHC03. The organic layer was washed with brine, dried (MgS04), filtered and the filtrate was concentrated to dryness. Purification of the crude product by column chromatography over silica gel afforded the product. 

Typical procedure Phenyltellurotrimethylsilane (2.10 mL, 10.9 mmol) was added into astirred solution of benzoyl chloride (1.42 g, 10.1 mmol) in 30 mL of dry tetrahydrofuran under an argon atmosphere. The mixture was stirred for 3 h at room temperature and concentrated under a reduced pressure. The residual Te-phenyl tellurobenzoate was purified by recrystallization from pentane to give yellow needles. Yield 2.71 g (87%). 

The first fixed-bed application of a supported ionic liquid-phase catalyst was hydroformylation of propylene, with the reactants concentrated in the gas phase (265). The catalyst was a rhodium-sulfoxantphos complex in two ionic liquids on a silica support. The supported ionic liquid phase catalysts were conveniently prepared by impregnation of a silica gel with Rh(acac)(CO) and ligands in a mixture of methanol and ionic liquids, [BMIMJPFg and [BMIM][h-C8Hi70S03], under an argon atmosphere. 

Films deposited in a glow discharge always contain concentrations of gases which make up the ambient atmosphere. For argon, the concentrations may vary between 0.1-50 at. %, depending upon the situation. 

To a solution of 1.5 mmol of KDA, prepared from potassium lerl-butoxide, diisopropylamine and butyl-lithium, in 7 mL of diethyl ether is added dropwise, under an argon atmosphere, a solution of 0.293 g (1 mmol) of (/ )-2-methoxy-2-phenyl-l-[( )-3-phenyl-2-propenyloxy]propane in 2 mL of diethyl ether at — 100 °C (liquid nitrogen/methanol). After stirring for 5 h the resulting dark-red suspension is treated with a solution of 0.284 g (2 mmol) of iodomethane in 1 mL of diethyl ether. The mixture is stirred until the red color disappears (about 2 h). Then, the bath is removed and 5 mL of phosphate buffer (pH 7) are added, the mixture is extracted with ethyl acetate several times. The extracts are washed with aq NaCl, dried over MgS04, and concentrated. The residue is purified by TLC on silica gel to give (7 )-2-methoxy-2-phenyl-1-[(ii)-3-phenyl-l-butenyloxy]propane yield 0.232 g (75%). This is hydrolyzed to 3-phenylbutanal by treatment with aq perchloric acid (40 %)/diethyl ether. 

The rate of the reoxidation of Mg deposits is controlled by their morphology, which in turn depends on the substrate material. Smooth and compact deposits were obtained using silver or gold, but not nickel or copper. It was also established that the open circuit potential (OCP) of magnesium electrode (a fresh deposit on a Pt) in concentrated solutions of 5 depends strongly on the solvent used. In THE solutions with c around 1 M at 22 °C under argon atmosphere, the values of OCP for 5a, 5b and 5f were equal to —2.8, —2.73 and —2.77 V vs. Ag+/Ag, respectively-. ... 

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