Caesium peroxide

Caesium peroxides.—Three peroxides have been prepared by heating... 

For caesium peroxide, over the composition range Cs20,.5—Cs2Oi.94 at 320—500 °C, the reaction path is 161... 

See Barium peroxide Non-metal oxides Caesium oxide... 

Fluorination of caesium heptafluoropropoxide at —40°C with nitrogen-diluted fluorine exploded violently after 10 h. This may have been caused by ingress of moisture, formation of some pentafluoropropionyl derivative and conversion of this to pentafluoropropionyl hypofluorite, known to be explosive if suitably initiated. Other possible explosive intermediates are peroxides or peresters. 

Hydrogen can of course also be lost if it is oxidised to water instead of the hydrogen peroxide that is needed for epoxidation. Its consumption can be lowered by 90% and selectivity raised to 97% at 1.7% conversion by admixing Au/Ti-MCM-41 with caesium chloride,23 but it is unclear how it acts. Water has however been found to decrease the rate of deactivation of Au/Ti02.24 25... 

It has been demonstrated by labelling studies that, in reactions with caesium trifluoro-methoxide, ring-opening occurs by attack at the peroxide bond [197] (Figure 8.66). 

The rubidium hydroxide of commerce is a monohydrated rubidium hydroxide, RbOH.H20, which melts at 145°, and at 350° it is completely dehydrated to RbOH. At a higher temp, it begins to peroxidize and attack the crucible. The heat of soln. of the monohydrate is 3 702 Cals, at 15°. The commercial caesium hydroxide is likewise a mouohydrated ceesiuiti hydroxide, CsOH.HgO it melts at 180°, and is completely dehydrated between 400° and 500°, and at the same time the mass begins to peroxidize. To prepare the pure hydroxide, it must be dehydrated in a current of dry hydrogen at 500°. The heat of soln. of the monohydrate is 4 317 at 15°. 

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 ... 

Potassium, rubidium and caesium also form oxides of the composition M2O3. When white KgOg is heated in oxygen at very low pressure red K2O3 is produced. The magnetic susceptibilities of RbgOg and CsgOg are consistent with the presence of superoxide ions, Og , and peroxide ions, Og , in the proportion 2 1. 

Biofilm formation at the air-water interface. The bathtub ring often formed at the air-water interface around the sides of the basin is likely to be a biofilm due to microbial activity. This film acts like a trap and is known to concentrate caesium and other radioactive isotopes contained in the basin water. This biofilm should be removed mechanically by wet brushing, using water to hold down any airborne activity. A 35% solution of hydrogen peroxide has proven effective in suppressing microbial activity and could be used to assist in biofilm removal without corrosive attack on aluminium alloys. 

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... 

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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