Fractionation evaporative

Anhydrous planetesimals, and especially the meteorites derived from them, provide crucial cosmochemical data. Spectroscopic studies of asteroids do not provide chemical analyses, but the spectral similarities of several asteroid classes to known meteorite types provide indirect evidence of their compositions. The few chemical analyses of asteroids by spacecraft are consistent with ordinary chondrite or primitive achondrite compositions. Laboratory analyses of anhydrous meteorites - chondrites, achondrites, irons, and stony irons - allow us to study important chemical fractionations in early solar system bodies. Fractionations among chondrites occur mostly in elements with higher volatility, reflecting the accretion of various components whose compositions were determined by high- and low-temperature processes such as condensation and evaporation. Fractionations among achondrites and irons are more complex and involve partitioning of elements between melts and crystals during differentiation. 

Evaporation and Evaporative Fractionation of Water. Evaporation from standing water bodies is the principal fractionation mechanism in most hydrological systems. Evaporative isotopic enrichment is a function of numerous factors (e.g., temperature, salinity, and relative humidity) that cause considerable variation in the lsO/ ieO and D/H ratios of natural surface waters. Craig and Gordon (22) evaluated isotopic effects on precipitation and evaporation in the ocean-atmosphere system. Much of what was developed in that work is directly applicable to the freshwater systems discussed here. 

Hexanedinitrile (adiponitrile). Use 150 ml of dry dimethyl sulphoxide, 21.2 g (0.17mol) of 1,4-dichlorobutane (Expt 5.52) and 20g (0.41 mol) of dried sodium cyanide. Maintain the reaction temperature at 90 °C for a further 15 minutes after the initial exothermic reaction has subsided. Add 150 ml of dichloromethane to the cooled reaction mixture and pour into an excess of saturated sodium chloride solution in a separatory funnel. Add just sufficient water to dissolve precipitated salts and separate the dichloromethane layer. Extract the acqueous layer once with dichloromethane, wash the combined extracts twice with salt solution, dry over magnesium sulphate and remove the solvent using a rotary evaporator. Fractionally distil the residue under reduced pressure and collect the adiponitrile as a fraction of b.p. 140-141 °C/ 1.5mmHg. The yield is 14.6g (81%). Some dimethyl sulphoxide (b.p. 40-42°C/1.5mmHg) may be obtained as a forerun. 

In order to simulate the condensing system of an industrial vacuum pyrolysis plant which consists of two condensing packed towers continuously operating, the liquids collected in each trap were mixed and then evaporated at 45 "C during half an hour in a rota-vapour (Biichi, RE 111). The heavy fraction which remained in the flask corresponds to the oil from the first condensing tower and is called bio-oil , while the evaporated fraction which consists of water and light organic compounds corresponds to the aqueous phase of the second tower and is called "aqueous phase . 

The concentration of potassium in sea water amounts to 0.38 g/1. The element is essential to plant growth and a necessary component of a balanced agricultural fertilizer. Potassium salts widely produced from brines are major constituents of the concentrated brines after sodium chloride has been removed through evaporation. Fractional crystallization usually results in recovery of potassium in the form of... 

To a stirred suspension of NaH (1.2 g, 50 mmol) in DMF (100 mL) was added trimethyloxosulfonium iodide (11.4g, 52 mmol) in one portion under N. Vigorous evolution of hydrogen lasted for ca. 5 min. After a further 15 min, a solution of diethyl propylidenemalonate (10 g, 50 mmol) in DMF (50 mL) was added in one portion, and the mixture was stirred for 1 h. The mixture was poured into 10% HCl/ice mixture (100 mL) and the resultant acidic solution (pH 1-2) extracted with EtjO (4x). The combined organic extracts were washed with HjO, dried (NajSO, ) and evaporated. Fractional distillation gave the required product yield 7.2 g (72%) bp 70 C/0.2 Torr. 

Bromomethyl)-naphthalene [939-26-4] M 221.1, m 52-54", 56", 56-57", b 133-136"/0.8mm, 214"/100mm. Dissolve the bromo compound in toluene, wash it with saturated aqueous NaHC03, dry (Mg SO4), evaporate, fractionally distil the residue and recrystallise the solidified distillate from EtOH. [Chapman Williams J Chem Soc 5044,1952, Bergmann Szmuszkovicz Bull Soc Chim Fr 20 566 1953, Beilstein 5 IV 1698.]... 

Cinnamyl alcohol 363 Freshly distilled cinnamaldehyde (21.7 g, 0.165 mole) is added to a suspension of sodium hydridotrimethoxyborate (40 g) in ether (100 ml), whereupon the mixture begins to boil. The whole is heated for 4 h, under reflux, then the vessel is cooled and dilute sulfuric acid is added until evolution of hydrogen ceases. The ethereal solution is dried over sodium sulfate and the solvent is evaporated. Fractional distillation gives 80% (17.5 g) of cinnamyl alcohol, b.p. 134-135°/13 mm. 

Methylenecyclohexane Cyclohexanone (9.8 g, 0.1 mole) is added to a solution of methylenetriphenylphosphorane (0.1 mole) in anhydrous ether (200 ml). A white precipitate is at once formed. The whole is warmed for 3 h at 65°, then the precipitate is centrifuged off and washed several times with ether. The ethereal, solutions are washed with water and evaporated. Fractionation of the residual oil through a Vigreux column (30 cm) affords methylenecyclohexane (5.4 g, 52%), b.p. 100-103°/744 mm. 

The objectives of this study are to illustrate, in terms of commercial PVT data, and Slope Factors (SF) summarizing the compositional information therein, three fundamental processes affecting the make-up of petroleums the maturation of oil, its modification by the admixture of gas and gas-condensate, and the generation of gas-condensates by evaporative fractionation as a consequence of gas addition. 

Biodegradation is expressed in molar profiles as a valley , initially centred on Pjo, which progressively widens and deepens. Two cusps develop in the profile, one at each end of the depleted range. The cusp at the lower end, commonly at Pg, remains when the front end has been markedly depleted, commonly by degasification in addition to biodegradation. The residual Pg cusp serves to distinguish front end depletion due to biodegradation from that due to evaporative fractionation. The latter process leaves a smooth front end profile as illustrated later. 

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