On the surface of magnesia

General Procedure for the Phosphorylation of Phenol with Diethyl Chlorophosphonate on the Surface of Magnesia. Magnesia (0.3 g) was added to a mixture of diethyl chlorophosphonate (0.86 mL, 6 mmol) and the phenol (5 mmol). This mixture was stirred at room temperature or 60 °C for 0.25-1 h. The solid mixture was washed with dichloromethane (4x25 mL). The solution was then washed with a dilute NaOH solution and a saturated sodium chloride solution and dried over MgS04. After evaporating of solvent, the crude product was isolated in a pure state by distillation in vacuo in 85-95% yield. 

Scheme 3. Best syntheses of various osmium clusters on the surface of magnesia pretreated at 400...

Information on the chemical state of iridium on going from the molecular precursors, and its adsorption on the surface of the support can be obtained by Ir Mossbauer spectroscopy. It allows to estimate the composition of the Ir-containing alloys that are possibly formed during the activation treatment of supported bimetallic systems. The main results obtained in the application of Ir Mossbauer spectroscopy to characterize two Ir-containing bimetallic supported nanoparticles, i.e., Pt-Ir on amorphous silica and Fe-Ir on magnesia are presented and discussed... 

However, when Ru3(CO)i2 was adsorbed on the surface of a basic metal oxide such as the decarbonated surface of magnesia, a similar nucleophilic attack was demonstrated to occur with formation of the anionic [HRusjCOjn]" species on the magnesia surface [42]. 

The saltpetre of commerce is derived principally from the East Indies, where, as also in Persia, Egypt, and Spain, it appears as an efflorescence on the surface of the soil. In some other countries, as the coast of the Adriatic, in Ceylon, North America, Africa, and Tene-riffe, it is found on the walls of natural caverns formed in limestone rocks, and which contain also felspar and magnesia. It is also found widely distributed in some parts of Hungary, but in no case extending to any great depth below the surface of the ground, nor even to such a depth as the air cannot penetrate. Its appearance on the surface of the ground is explained by its ready solubility in water, as when ite solution, in obedience to the law of capillary attraction, rises to the surface, the liquid is vaporized by the action of sun and air, and its place is immediately occupied by a fresh portion from below, which disappears in the same manner, until at last an incrustation of the salt is formed of considerable thickness, either in solid crystals, or as an effloresced mass. 

Carbon unites with molten iron, forming a carbide hence the product of the blast-furnace is not pure iron, but a mixture of iron with its carbide, and also with its sulphide and phosphide, if the ore has contained sulphates or phosphates. When such impure iron is brought in contact with oxygen in a molten or semi-molten condition, the carbon, sulphur, and phosphorus are oxidised mostly before the iron. If lime be present, sulphate and phosphate of calcium are formed. The modern process of removing these impurities is to pour the molten metal into a pear-shaped iron vessel lined with bricks made of magnesia while it is molten, air is blown through the metal, and the carbon burns to carbon dioxide the sulphur and phosphorus are likewise oxidised and combine with lime, a layer of which floats on the surface of the molten metal When these impurities have thus been removed in the Bessemer... 

According to ESCA measurements carried out with vanadium oxide, consistent with the data presented in [12], the Ols characteristic of On oxygen species is very close to the V=0 doubly bonded oxygen atoms exposed at the surface of (010) planes of V2O5 crystals. The oxygen species with Ols characteristic of Oi do not exist at the surface of individual main components of catalysts A,B - vanadia, molybdena, or exist in small concentration at the surface of magnesia or TM. They... 

A major U.S. float glass manufacturer used a burned magnesia brick as part of the furnace regenerator package in a gas-fired furnace. After approximately 5 years service, the checkers experienced a partial coUapse. Several pieces of broken brick were pulled from the debris pile under the checkers for analysis. Table 2 contains chemical analysis data on a representative sample of the used brick, on the original unused brick, and of buildup taken from the surface of the brick. The unused brick had a CaO content of 2.05% while samples taken from the exterior and interior of the used brick had much lower CaO contents of 0.19 and 0.14%, indicating depletion of CaO during service. The buildup on the surface of the brick contained... 

We have previously studied the role played by the support (silica, alumina, magnesia and titania, both anatase and rutile) on the surface properties of vanadia (ref. 6-9), concluding that the interaction between the support and the supported phase, and hence their activity in the above mentioned processes, greatly depends on the difference in their basicities. The aim of the present paper is to insight in this study, analyzing the role played by a usual dopant (sodium) on the properties of alumina- and titania- supported vanadia, using two different methods to incorporate vanadia on the surface of the support, i.e., standard impregnation methods and mechanical mixture of the oxides, as we have observed (ref. 7 and 9) that some of the properties of the final... 

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