Rare volatility enhancement

It has been established that the apparent volatilities of transition and rare-earth metal halides are increased by several orders of magnitude through reactions of type (1) and (2) giving rise to vapor complex formation. The enhancement of the vapor densities of transition metal and/or rare-earth metal ions has commonly (see for example Papatheodorou 1982) been reported in the form of the uolatility enhancement factor. That is, when a reaction occurs between a solid rare-earth halide with low vapor pressure Ps (e.g. NdCb) and a more volatile salt (carrier gas) with partial pressure P (e.g. AlCl3,NaCl), and the partial pressure of the vapor complex is Pq, then the volatility enhancement factor is determined at unit pressure of the carrier gas as ... 

Experiment 2 Saturate distilled water with a rare gas and compare the intensity of the signal with that from air. The luminosity will be enhanced in the rare gas saturated solutions. For any gas atmosphere, add small amounts of volatile water-soluble solutes (e.g. alkyl series alcohols) and quantify the quenching of sonoluminescence as a function of both bulk quencher concentration and surface excess. Good correlation between the extent of quenching and the Gibbs surface excess should be observed. Explain the changes in sonoluminescence intensity when a rare gas atmosphere is used and the quenching of volatile solutes, in terms of simple thermodynamics. 

Many catalytic formulations have been proposed to enhance the-performance of cupric chloride, the only active phase developed to the industrial stage. Hence other metallic chlorides are combined with it (potassium, rare earths, etc.) to increase the selectivity of the reaction, reduce the volatility of the copper compounds, prolong catalyst life, etc. Various supports are also used, generally based on alumina, but also kieselguhr, sflico-aluminates and diatomaceous earths. 

Enhancing of complex volatility from early to heavy rare earths is explained by increasing of the crowding of the central ion by ligands, which in turn leads to decreasing of the intramolecular interaction [97]. The value of sublimation enthalpy as well as the enthalpy... 

The formation of vapor complexes between the transition and rare-earth metal halides and the acidic trihalides of Al, Ga, In and Fe resulting in enhanced apparent volatilities is recognized as a common phenomenon (see e.g. Papatheodorou 1982, Brooker and Papatheodorou 1983). Among the Group-lllA halides, aluminum chloride has been by far the most widely used vapor complex forming agent in this respect, while AlBrs, GaCb, InCls and FeCls have been also used to a lesser extent. 

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