Fractional condensation

Fractional condensation can be handled like fractional crystallization with rain water (w) instead of solid, and vapor (v) instead of liquid. Then, the Dni2 fractionation 

The last term in the right-hand side of the last equality is obviously very close to unity, therefore 

The 8 notation is more convenient and, since SMOW values, by definition, are constant, we get 

The linear expansion of the natural logarithm in a Taylor series 

Craig (1961) found that the slope of the correlation between 8lsO and 5D in precipitation is constant and equal to 8 which is reasonably consistent with atmospheric temperatures. 

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Magnetic vector potential A Mole fraction, condensed X... 

The reaction of chlorine gas with a mixture of ore and carbon at 500—1000°C yields volatile chlorides of niobium and other metals. These can be separated by fractional condensation (21—23). This method, used on columbites, is less suited to the chlorination of pyrochlore because of the formation of nonvolatile alkaU and alkaline-earth chlorides which remain in the reaction 2one as a residue. The chlorination of ferroniobium, however, is used commercially. The product mixture of niobium pentachloride, iron chlorides, and chlorides of other impurities is passed through a heated column of sodium chloride pellets at 400°C to remove iron and aluminum by formation of a low melting eutectic compound which drains from the bottom of the column. The niobium pentachloride passes through the column and is selectively condensed the more volatile chlorides pass through the condenser in the off-gas. The niobium pentachloride then can be processed further. 

In oil and gas refinery appHcations, titanium is used as protection in environments of H2S, SO2, CO2, NH, caustic solutions, steam, and cooling water. It is used in heat-exchanger condensers for the fractional condensation of cmde hydrocarbons, NH, propane, and desulfurization products using seawater or brackish water for cooling. 

Figure 1 Schematic of DC glow-discharge atomization and ionization processes. The sample is the cathode for a DC discharge in 1 Torr Ar. Ions accelerated across the cathode dark space onto the sample sputter surface atoms into the plasma (a). Atoms are ionized in collisions with metastable plasma atoms and with energetic plasma electrons. Atoms sputtered from the sample (cathode) diffuse through the plasma (b). Atoms ionized in the region of the cell exit aperture and passing through are taken into the mass spectrometer for analysis. The largest fraction condenses on the discharge cell (anode) wall.

One of the most important operations in a refinery is the initial distillation of the crude oil into its various boiling point fractions. Distillation involves the heating, vaporization, fractionation, condensation, and cooling of feedstocks. This subsection discusses the atmospheric and vacuum distillation processes which when used in sequence result in lower costs and higher efficiencies. This subsection also discusses the important first step of desalting the crude oil prior to distillation. 

In general, refining consists of two major phases of production. The first phase of production acts on the crude oil once as soon as it enters the plant. It involves distilling or separating of the crude oil into various fractional components. Distillation involves the following procedures heating, vaporization, fractionation, condensation, and cooling of feedstock. 

The preparative reactions were conducted in sealed tubes in which — 1-3 g of the reagents had been placed. After the vessels had been maintained at the indicated temperatures for the designated times, the contents were removed, to be separated by fractional condensation and GLC. In addition to the (trifluoromethyl)Group 4A halides reported next, each sample contained unreacted (CFalaHg, the expected (tri-fluoromethyDmercuric halide, and the mercuric halide, identified by fluorine-NMR spectroscopy and mass spectrometry. 

Several other processes for extracting Be from beryl have been patented the most feasible involves the formation of BeCl2 by direct chlorination of beryl under reducing conditions several volatile chlorides are produced by this reaction (BeCl2, AICI3, SiCl4 and FeClj) and are separated by fractional condensation to give the product in a pure state. Other methods involve the fusion of beryl with carbon and pyrites, with calcium carbide and with silicon. 

This procedure differs from those outlined for the bromo and chloro derivatives in that an appreciable excess of (dimethyl-amino) diflu orophosphine cannot be used because it is difficult to separate from iododifluorophosphine by fractional condensation. Typically, (dimethylamino)difluorophosphine (6.38 mmol) and hydrogen iodide (12.76 mmol) are condensed into a 500-ml. reaction bulb and allowed to warm slowly to 25°. As reaction ensues, f the white solids are discolored by formation of red phosphorus triiodide which probably results from a disproportionation 3PF2I —> 2PF3 + PI3. Thus, when the products are separated by fractional condensation through —126° (methylcyclohexane slush) to —196°, an appreciable amount of... 

The probable impurities in radioactive phosphorus trichloride are hydrogen chloride and phosphorous acid the trichloride is, therefore, purified by fractional evaporation and fractional condensation in the high-vacuum system. Pure ethylphosphonous dichloride is prepared according to the equation ... 

Hi) undergo fractionation, condensation or adsorption of components during the course of transfer to the column. 

In entrainer sublimation, an entrainer gas is blown into the vaporisation chamber of a sublimer in order to increase the vapour flowrate to the condensing equipment, thereby increasing the yield. Air is the most commonly used entrainer, though superheated steam can be employed for substances such as anthracene that are relatively insoluble in water. If steam is used, the vapour may be cooled and condensed by direct contact with a spray of cold water. Although the recovery of the sublimate is efficient, the product is wet. The use of an entrainer gas in a sublimation process also provides the heat needed for sublimation and an efficient means of temperature control. If necessary, it may also provide dilution for the fractional condensation at the desublimation stage. Entrainer sublimation, whether by gas flow over a static bed of solid particles or through a fluidised bed, is ideally suited to continuous operation. 

Chlorination of thiols serves for the preparation of temperature-sensitive sulfenyl halides, since the main reaction products are easily separated from the side products by fractional condensation, e.g.,... 

Chloryl fluoride is slightly less volatile than CIF3O2, and, therefore, most of it can be removed from CIF3O2 by fractional condensation in a —112°C trap. The remaining FClOg, however, has to be removed by complexing with BFg ... 

Once in the column, volatile compounds vaporize and less-volatile liquids drop to the bottom of the column. Reflux begins and oil fractions condense and collect in various trays throughout the column. Heating within the column can influence the rate of reflux and holdup within the column. Steam is introduced into the column at the level of the lower trays and strips lighter compounds from the condensed fractions on these trays. As a result, the flash point of the fractions remaining on the lower trays increases. 

CFjSCl (5 mmol) and CIF (25 mmol) were condensed in a 75-mL Monel Hoke cylinder and reacted for 10 h at 25 C. Fractional condensation was employed to separate the desired product CF,SF4CI front unreacted CIF, Cl2, and small amounts of low-boiling byproducts, such as CF4, CF,CI. SF4, CF,SF5, using traps at — 116, — 131, and —183 C. The trap at —116 C contained liquid CF,SF4C1 slightly contaminated with Cl2. This was agitated with a small amount of molecular sieves in a Pyrcx tube until the yellow color disappeared yield 56.5% bp 20.1 C. 

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