U-pentane

Aware of the enhanced reactivity of trivalent [( ArO)3tacn)U] towards non-innocent solvents, such as ethers and chlorinated solvents, the reactivity of this molecule was challenged by exposure to more inert solvents like alkanes. Remarkably, recrystallization of 4 -bu u pentane solutions containing various cycloalkanes, i.e., methylcyclohexane, afforded the coordination of one cycloalkane molecule to the electron-rich U center (Scheme 4) (37). 

Mixture of hydrocarbons, typically 73% u-pentane, 23% branched pentanes, 3% cyclopentane. Higher boiling petrols have correspondingly decreasing flammability hazards. 

Fig. 1 Phase diagrams of methanol mixtures with (A) ethyl ether at 115°C and (B) u-pentane at 99.6°C. (From Refs. . ) (View this art in color at WWW. dekker. com.)...

The-purity of a /i-pentane sample was determined by a calorimetric method by Clarke et al. (20). The results obtained for pure u-pentane and for a synthetic n-penlane-iso-octane mixture are given in the resistance (temperature) versus time curve in Figure 10.11. For purity determination, these data have been converted to the fraction melted after each equilibration period by allowing for the heat necessary to raise the temperature of the solid and liquid and for the amount of heat leak from radiation and conduction. The heat of fusion determined from this work was 2090 calories per mole, which gave a purity of 99.79 mole-% for the n-pentane. 

The alcohol with five carbons (u-pentanol) would be the best solvent for iodine (a) and u-pentane (c) (why ). Methanol (CH3OH) is the most water like and is the best solvent for an ionic solid like KBr. 

Fig. 2.12 Plot of the calorimetric difTeFential enthalpy of adsorption A h) against amount adsorbed (n), for (u) n-pentane, (f)) /i-hexane, (c) n-heptane, d) n-octane, all adsorbed on graphitized car n black. The point corresponding to n = is marked on each curve. (Courtesy Kiselev.)...

C. In their first series of experiments, six data sets were obtained for (H) and (u), employing six solvent mixtures, each exhibiting different diffusivities for the two solutes. This served two purposes as not only were there six different data sets with which the dispersion equations could be tested, but the coefficients in those equations supported by the data sets could be subsequently correlated with solute diffusivity. The solvents employed were approximately 5%v/v ethyl acetate in n-pentane, n-hexane, n-heptane, -octane, -nonane and n-decane. The solutes used were benzyl acetate and hexamethylbenzene. The diffusivity of each solute in each solvent mixture was determined in the manner of Katz et al. [3] and the values obtained are included... 

Reviews covering the chemistry of group 2 metal complexes with phosphorus-stabilized carbanions,279 and of molecular clusters of magnesium dimetallated primary phosphanes, are available.2 u Magnesium phosphanes remain rare compounds.281 Lithiation of bromide 98 with BuLi in the presence of tmeda in pentane produces a lithium phosphine dimer subsequent treatment with MgCl2 in EtzO gives the phosphane 99 in 69% overall yield (Equation (19)). The centrosymmetric 99 has Mg-C = 2.217 A Mg-P = 2.77 A (av.).282... 

Mills, W.B., Dean, J.D., Porcella, D.B., Gherini, S.A., Hudson, R.J.M., Frick, W.E., Rupp, G.L., Bowie, G.L. (1982) Water Quality Assessment A Screening Procedure for Toxic and Conventional Pollutants. Part 1, U.S. EPA, EPA-600/6-82-004a. Mokbel, I., Rauzy, E., Loiseleur, H., Berro, C., Jose, J. (1995) Vapor pressures of 12 alkylcyclohexanes, cyclopentane, butylcyclo-pentane and frara -decahydronaphthalene down to 0.5 Pa. Experimental results, correlation and prediction by an equation of state. Fluid Phase Equil. 108, 103-120. 

Despite its fleetingness, 78 has been captured by CO in a matrix at 10 K, affording low yields of ketene." Modarelli and Platz were unable to observe the formation of a pyridine ylide upon LFP generation of 78 in pyridine/pentane at —40°C. However, with perdeuterated methylcarbene (78- 4) a weak pyridine ylide signal was detected, and the rate constant of the 1,2-D shift could be estimated as ito 2 x 109 s-1 (r 0.5 ns) using a Stem-Volmer analysis (see Eqs. 3-6 in Section II).89 The activation energy for this 1,2-D shift was estimated at 2.3 kcal/mol, assuming A 1011 s-1.89 However, it seems likely that both 2sa and A are somewhat lower, with A 108 to 109 s (AS = —17 e.u.).89... 

Drizo A variation of the glycol process for removing water vapor from natural gas, in which the water is removed from the glycol by stripping with a hydrocarbon solvent, typically a mixture of pentanes and heavier aliphatic hydrocarbons. The process also removes aromatic hydrocarbons. Last traces of water are removed from the triethylene glycol by stripping with toluene in a separate, closed loop. Invented in 1966 by J. C. Arnold, R. L. Pearce, and H. G. Scholten at the Dow Chemical Company. Twenty units were operating in 1990. U.S. Patent 3,349,544. 

The first successful isolation of a mononuclear uranium-tacn complex was achieved by treatment of the free l, 7-tris(3,5-di-fert-butyl-2-hydroxybenzyl)-1,4,7-triazacyclononane (( ArOH)3tacn) (4 - ) (25) with one equivalent of [U(N(SiMe3)2)3] (35) in cold pentane... 

If all the pentane is removed before pyrolysis, the bicyclo [2.1.0]pentane shows no impurities on vapor phase chromatography with a 20% Dow 710 on 50/60 U Anaprep column. Analysis by n.m.r. also revealed the absence of any traces of cyclo-pentene in the spectrum consisting of three complex multiplets at 0.3-0.8, 1.1-1.7, and 1.9-2.4 p.p.m. (downfield from internal tetramethylsilane reference). 

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