Caesium monoxide

The standard free energy of formation, AG°, of caesium monoxide has been calculated from experimental results as -308.42 1.18 kcal mol-1. To permit practical thermodynamic calculations to be made at higher temperatures, experimentally determined heat capacities at 5—350 K have been extrapolated to 763 K, the m.p. of Cs20, and a table of extrapolated thermodynamic functions, including AG°, is now available up to 763 K.162... 

The standard enthalpy of formation, AH°, of caesium monoxide is —82.69 0.28 kcal mol-1. This value was derived from a solution-calorimetry study of high-purity Cs20 dissolving in excess water to form CsOH(aq).163... 

Trifluoromethyl hypofluorite was first made by Cady by passing methanol [184] or carbon monoxide [185, 186] with fluorine over silver difluoride at elevated temperatures. Later, trifluoromethyl hypofluorite and higher perfluoroalkyl hypofluorites were prepared by treating the appropriate carbonyl compound with fluorine in the presence of dry caesium fluoride at sub-zero temperatures (Fig. 81) [187-189]. 

The metals burn in oxygen to yield (i) lithium monoxide, (ii) sodium peroxide and (hi) pota.ssium, rubidium and caesium superoxidcs (p. 384). Successive additions of oxygen giv e the oxide (O ), peroxide (02 ) and superoxide (Og") anions ... 

The vaporization of CsN03 has been investigated by mass spectrometry. The enthalpies of vaporization of monomeric CsN03(g) and dimeric (CsN03)2 are 28.2 and 29.3 kcal mol"1, respectively, at 298 K. The enthalpy of dimerization of caesium nitrate is -27.1 kcal mol"1 at 298 K.281 The thermal decomposition of potassium oxalate in molten KN03 at 350 °C yields K2C03, KNOz, and C02. There was no trace of carbon monoxide.282 The extraction of Co11 and some 4f (Pr, Eu, Tm) and 5f (Am, Cm, Cf)... 

Fischer s experiments with iron catalysts promoted with alkalies showed that they increased in efficiency with the strength of the base, with the exception of caesium. Working with catalysts prepared by calcining steel turnings with potassium hydroxide, Frolich and Lewis 1J7 showed that with a gas containing 40 per cent carbon monoxide passed into the reactor at a space velocity of 1250 at 200 atmospheres and 325° to 335° C. the best yields were obtained when the base comprised 2.2 per cent of the catalysts (calculated as K20). From this it appears that a strong base present in small amount with iron as the catalyst enables the best yields of liquid products to be obtained. This conclusion has been confirmed by the work of Audibert and Raineau. 

Bis(iluoroformyl) peroxide, prepared from carbon monoxide, oxygen, and fluorine at 55 cyclizes to the cyclic peroxide (77) when left in contact with potassium fluoride at — 80 °C, presumably via a mechanism of the type proposed for fluoride-initiated conversion of the bis(acyi) fluoride CKCFjCOF) into perfluoro-j3-oxa-8-valerolactone (see Vol. 1, p. 76) use of caesium fluoride at -40 °C gives a mixture of the acyclic peroxides (CFs-0-0)sC0 and CFj-O-O COF, possibly via attack of F on the CF group of (77). The 1,2-dioxolan (78) can be obtained by direct fluorination of the copper chelate of l,l,l,5,5,5-hexafluoropraitane-2,4-dione at —20... 

The presence of thallium(0) led to an increase in activity and selectivity of metallic palladium catalysts supported on silica in aldose oxidation reactions. However, silica-supported thallium(0) had no activity by itself (entry 3). ° Similarly, the bimetallic catalyst platinum-thallium/ZSM-5, prepared by impregnation of thallium sulfate and chloroplatinic acid on Zeolite Socony Mobil-5 (ZSM-5), showed greater selectivity in propane aromatisation and almost the same catalytic activity as monometallic thallium/ZSM-5 (entry 4). Similar comparison of vanadium-caesium-copper and vanadium-caesium-copper-thallium catalysts supported on TiOa.SiC demonstrated that addition of thallium improved the catalytic activity in partial oxidation of p-tert-butyltoluene to p-tert-butyl-benzaldehyde (entry The application of solid-supported thallium-based catalysts in different processes includes (a) iron-thallium catalysts in carbon monoxide hydrogenations to form hydrocarbons and alcohols, and catalytic reforming of... 

Studies on the well known reaction between fluorine and carbon monoxide have revealed that a film of silver fluoride(s) on copper truly is a catalyst for the reaction Fj + CO - COFa, and for subsequent changes producing bistrifluoromethyl peroxide and trifluoromethyl hypofluorite, whereas caesium fluoride is not and since neither copper nor silver iluoride(s) appears to be a good catalyst for the reaction CF3 OF + COFj CFa O O CFg, it has been suggested that the fluorination of carbon monoxide or carbonyl fluoride in the presence of silver difluoride may possibly involve the steps... 

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