Potassium vaporization

During operation, KCl is melted and introduced through a trap to the column. Molten sodium is fed to the bottom of the column. The lower portion of the column serves as a reactor, the upper portion as a fractionator. Potassium vapor is fractionated and condensed in an air-cooled condenser with the reflux pumped back to the top of the column. Waste sodium chloride is continuously removed from the bottom of the column through a trap. 

Although the equilibrium constant for this reaction is not particularly favorable, the reaction runs to the right because potassium is more volatile than sodium the potassium vapor is driven off by the heat and condensed in a cooled collecting vessel. 

Under severe conditions (above 700°C), a potassium vapor is formed. It plays a special role in the activation of carbonaceous materials, easily penetrating in the graphitic domains that form cage-like micropores. The efficient development of micropores, which often gives a few-fold increase of the total specific surface area, is very useful for the application of these materials in supercapacitors [13-14]. 

The chemiluminescent emission spectrum of GeCl2 was obtained by burning GeCl4 in potassium vapor using a diffusion flame technique 11 The spectrum consisted of a series of closely spaced diffuse bands in the region 4900—4100 A with an underlying continuum. The bands resemble those of SnCl2. 

J. G. Gahn in Sweden and N.-L. Vauquelin in France tried in vain to obtain metallic cerium. C. G. Mosander prepared anhydrous cerous chloride and subjected it for a long time to the action of potassium vapor. After washing the residue with cold alcohol, he obtained a brown powder which,... 

Although Sir Humphry Davy felt certain that silica is not an element, he was unable to decompose it with his powerful voltaic pile, and was also unsuccessful in his attempts to isolate silicon by passing potassium vapor over red-hot silica. Gay-Lussac and Thenard observed that silicon tetrafluoride and potassium react violently when the metal is heated, and that a reddish brown, combustible solid is obtained. This was probably very impure amorphous silicon (37, 39). 

All three compounds are prepared by elimination of bromine from the corresponding bridgehead-bridgehead dibromides. In the case of 3, this may be effected by butyllithium in a hydrocarbon solvent, but for 14 and 15 the elimination must be carried out by potassium vapor in the gas phase followed by trapping the product as an argon matrix at 10-15 K. 

K (g). The vapor pressure of potassium was measured by Kroner,1 Fiock and Rodebush,1 Edmondson and Egerton,1-2 and Killian.1 See also van Laar9 and Rodebush 2 Following the same procedure as with sodium, we have calculated that the amount of K2 in potassium vapor at these temperatures is less than 1%. For the heat of vaporization of K(liq.), we have selected V= —20.00 +0.0025(t+273.1) whence, for K(g),Q/= —19.80. 

Kamke, W. (1975). Nuclear magnetic resonance of K2 in optically pumped potassium vapor, Phys. Lett. A, 55, 15-16. 

Figure 4.1. The variation of the effective lifetimes / with potassium vapor pressure. t = 27.7 nsec (for the natural lifetime) and the encircled point on the aP3/2 curve were used to fit the theoretical curves, representing Holstein s [20,21] relation 1 lg = t jr to the experimental results.

The EUV Region. The results for the photoabsorption cross sections of potassium vapor in the energy region 50.8 nm - 76.0 nm are shown in Figure 2. 

The UV Region. The results for the relative cross sections of potassium vapor in the energy region of 210-400 nm are shown in Figure 3. Because of strong absorptions in this wavelength region the vapor pressure of potassium in the heat-pipe could not be reduced to the point such that the heat-pipe operation condition could still be sustained. The isothermal zone is thus not established. Therefore, only relative data are measured in the present work. 

Illite Vaporization. The clay mineral illite is frequently found as a mineral constituent of coal and is considered a major source of potassium vapor species in combustion systems. A "Beaver s Bend illite" sample was used (provided by the Morgantown Energy Technology Center) with the following composition for the major components, in vt.% Al203(26.0), Fe203(4.4), Si02(60.2),... 

Table II contains a summary of selected potassium vaporization data for these systems. With a few noted exceptions, the oxygen partial pressures coupled stoichiometrically with potassium, in keeping with reaction [3]. Hence, K20(A) activities can be derived, to a good to excellent approximation, using the corresponding dissociation-pressure data for pure liquid KgO. That is.

Experimental details and an extended discussion of these potassium vapor pressure results have either appeared, or will appear, elsewhere, as indicated in Table II. In general, the potassium vaporization data followed the expected Clausius-Clapeyron behavior, as indicated in Table II. Exceptions to this behavior could be traced to ... 

Colored crystals need not be gemstones in fact, a colorless crystal of potassium chloride may be suitably altered to exhibit color. When solid KCl is heated to 500°C in the presence of potassium vapor, the crystal becomes a violet color. This occurs due to the ionization of gaseous potassium atoms that abstract a Cl anion from the... 

A new technique (applicable also for [3.2.1]propellane (71), cf. Ref. 57) has been developed using gas phase dehalogenation of the bridgehead diiodide with alkali metal vapor and leading to the corresponding propellane. This is then followed by trapping in an inert gas matrix (Ar). The heretofore unknown [2.2.1]propellane (80) was prepared, accompanied by norbornane. The potassium vapor is diluted with a sonicated stream of nitrogen. 

Propellane (94) was synthesized from l,4-diiodobicyclo[2 l.l]hexane (93) using potassium vapor and isolated in a nitrogen matrix It was tentatively identified on the basis of its infrared spectrum. The paper includes a table of infrared frequencies for... 

Potassium vaporizes to a mixture of monatomic and diatomic gas. The total vapor pressure reaches 1 atm. at 1037 K. The vapor composition at this temperature is 94.5 mole % monatomic and 5.5 mole % diatomic gas. The enthalpy of vaporization of 39.1 grams of liquid potassium to this equilibrium mixture is 18.38 kcal. 

Parallels have been proposed between the dissolution of the alkali metals in nonaqueous solvents and the interactions of alkali metals with zeolites.The sorption of sodium or potassium vapor into dehydrated zeolites produces intensely colored compounds, ranging from burgundy red to deep blue, depending upon the metal concentration. A combination of EPR,... 

The preparation of metallic beryllium has been attended with some difficulties. Sir Humphry Davy attempted to reduce BeO with potassium vapor but failed. Later he fused iron filings and BeO, obtaining > a metallic mass, somewhat malleable, which was probably an alloy of iron and beryllium. Wohler, in 1827, prepared metallic beryllium for the first time, reducing BeCU with potassium and removing the KC1 from the impure beryllium by the greater solubility of the former. ... 

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