Cesium oxidation process

Other Applications. The refractive index of siUcate or borosiUcate glass can be modified by the addition of cesium oxide, introduced as cesium nitrate or carbonate. Glass surfaces can be made resistant to corrosion or breakage by surface ion exchange with cesium compound melts or solutions. This process can also be used for the production of optical wave guides (61). 

Alpha (2) A process for making methyl methacrylate, developed by Ineos Acrylics (now Lucite International) since 1990. Ethylene is carbonylated and methylated to produce methyl propionate, which is reacted with formaldehyde to produce methyl methacrylate. The first stage is homogeneously catalyzed by a palladium phosphine complex. The second stage is operated in the gas phase over a catalyst of cesium oxide on silica. Piloted by Davy Process Technology in 2002. The first commercial plant was opened in Singapore in 2008. The second was to be built in Texas by Mitsubishi Rayon for completion in late 2009. Lucite International received the 2009 Kirkpatrick Chemical Engineering Achievement Award for this development. Lucite is now a subsidiary of Mitsubishi Rayon. 

For each nuclide studied, the sorption distribution coefficients appeared to result from a minimum of two separate mechanisms. In all cases, one mechanism appears to be an ion-exchange phenomena associated with the silicate phases and appears to have a relatively much larger sorption capacity than the other mechanism. In the case of cesium (and probably rubidium) the second mechanism appears to also be related to the silicate phases and may or may not be an ion-exchange phenomena. However, for the other elements studied, the second mechanism appears to be related to the hydrous iron and manganese oxides and again may or may not be an ion-exchange process. 

The potential curves of the adsorption of cesium on a CaF2 surface are given in Fig. 21, which shows that the curve for the ion represents an endothermic chemisorption. By the absorption of light of suitable wave length the system is transferred from minimum B to a point P of the upper curve and an electron is freed and may be drawn off as a photoelectron. The phenomenon of the selective photoelectric effect could be fully explained by this photoionization process (174). By thermal excitation the transfer can be effected at point electron emission of oxide cathodes. Point S is reached by taking up an amount of energy, which may be called the work function of the oxide cathode in this case but which is completely comparable with the energy of activation in chemisorption discussed in Sec. V,9 and subsequently. We shall not discuss these phenomena in this article but refer to a book of the author where these subjects are dealt with in detail (174) ... 

Pyrochemical processes have the potential for low waste volume, but only if materials are recycled. No major problems are foreseen for recycle of the greatest bulk component, sodium nitrate. Regeneration will be required, but the presence of a considerable amount of nitrite is not a problem since nitrite also oxidizes uranium dioxide. Removal of the highly soluble fission products, such as cesium and iodine, will eventually require either a separation step or a bleed-off of the nitrate stream. 

The observed catalytic effect of the alkali metal carbonates and oxides and the alkaline earth oxides upon the gasification of the ESC deposit in water vapour again most probably derived from successive oxidation and reduction processes. A possible cycle carbonate-metal-hydroxide could be feasible at this temperature, at least for sodium, potassium and lithium (3) and conceivably also for cesium and rubidium. For barium and strontium the cycle could be between a higher and a lower oxide. Calcium, in contrast to barium and strontium, does not form a peroxide by oxidation of calcium oxide and in any case this would not be stable above 200°C, which could explain why calcium oxide was not an active catalyst. 

Rather than survey all of the possible modifications that can be made to an alumina surface, we will focus on a subset involved in two different types of surface-catalyzed chemical reactions, namely, the partial oxidation of ethylene to ethylene oxide (EO) and hydrodesulfurization (HDS) processes. Both of these catalytic systems have functional points in common, in that alumina serves as a support (a-alumina for the EO process and 7-alumina for the HDS process) and alkali-metal salts serve as promoters for both reactions. To illustrate this commonality, this section will be divided into three parts (1) the adsorption of alkali-metal salts to 7-alumina, as reflected in the Rb and Cs solid-state NMR spectroscopy of these systems (2) the absorption of ethylene to silver supported on aluminas in the presence and absence of cesium salts, as followed by C NMR spectroscopy, and (3) the solid-state Mo NMR of fresh and reduced/ sulfided molybdena-alumina catalysts. 

Here we show that the polarity of polymer solar cells can be reversed by changing the position of two interfacial layers vanadium oxide (V2O5) layer as hole injection and cesium carbonate (CS2CO3) layer as electron injection, independent of the top and bottom electrodes. ° Since our first demonstration of inverted solar cells, more and more interests have focused on this new architecture. Waldauf et al. demonstrated inverted solar cells with a solution-processed titanium oxide interfacial layer. White et al. developed a solution-processed zinc oxide interlayer as efficient electron extraction contact and achieved 2.58% PCE with silver as a hole-collecting back contact. It is noteworthy to mention that EQE value for inverted solar cells approaches 85% between 500 and 550 nm, which is higher than that of normal polymer solar cells. This is possibly due to (i) the positive effect of vertical phase separation of active layer to increase the selection of electrode and (ii) lower series resistance without the PEDOT PSS layer. 

The selective oxidation of ethylene to ethylene oxide (EO) is performed on supported silver catalysts at temperatures of250—280 °C, and a pressure of roughly 20 bar. In this process, it is necessary to avoid secondary reactions of EO. Typical industrial catalysts may contain 8—15 wt% silver dispersed on low surface area (X-AI2O3 (0.5-1.3 m g ) with a porosity of about 0.2—0.7 cm g In addition, the catalyst may contain several promoters in varying amounts (ppm by weight) 500—1200 ppm alkali metal (mostly cesium), 5-300 ppm of sulfur as cesium or ammonium sulfate, 10-300 ppm offluorine as ammonium fluoride, or alkaft metal fluoride (427). 

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