Silicon compounds, oxidation

All silicon compounds on oxidation yield silica or silicates these are difficult to detect but silica (given by silicates after acid treatment) is insoluble in all acids except hydrofluoric acid. 

Physical Properties. Physical properties of importance include particle size, density, volume fraction of intraparticle and extraparticle voids when packed into adsorbent beds, strength, attrition resistance, and dustiness. These properties can be varied intentionally to tailor adsorbents to specific apphcations (See Adsorption liquid separation Aluminum compounds, aluminum oxide (alumna) Carbon, activated carbon Ion exchange Molecular sieves and Silicon compounds, synthetic inorganic silicates). 

Traditional adsorbents such as sihca [7631 -86-9] Si02 activated alumina [1318-23-6] AI2O2 and activated carbon [7440-44-0], C, exhibit large surface areas and micropore volumes. The surface chemical properties of these adsorbents make them potentially useful for separations by molecular class. However, the micropore size distribution is fairly broad for these materials (45). This characteristic makes them unsuitable for use in separations in which steric hindrance can potentially be exploited (see Aluminum compounds, aluminum oxide (ALUMINA) Silicon compounds, synthetic inorganic silicates). 

Alkoxides of nonmetals are described in articles about the corresponding compounds (see Boron COMPOUNDS, Boron oxides Silicon compounds). Metal alkyls, in which the alkyl group is bound direcdy to the metal, are also discussed elsewhere (see Aluminum compounds). 

Relatively few examples are known which utilize an oxidative addition reaction of metal hydrides to necessarily low valent silicon compounds. Seyfert s hexame-thylsilirane (31) could be used as a source of dimethylsilylene to perform an... 

This oxidant reacts with many compounds. In organic chemistry it is an agent which entirely oxidises substances enabling one to measure them. In microbombs , the contact causes a small explosion. Thus silicon compounds are converted into silica, which can then be measured by gravimetry. When opening the bomb , overpressures can cause comosive substances (especially peroxide in excess) to be thrown up and cause harm. 

Silicon-containing ceramics include the oxide materials, silica and the silicates the binary compounds of silicon with non-metals, principally silicon carbide and silicon nitride silicon oxynitride and the sialons main group and transition metal silicides, and, finally, elemental silicon itself. There is a vigorous research activity throughout the world on the preparation of all of these classes of solid silicon compounds by the newer preparative techniques. In this report, we will focus on silicon carbide and silicon nitride. 

The reaction described is of considerable general utility for the preparation of benzoyloxy derivatives of unsaturated hydrocarbons.2"8 Reactions of 2-butyl perbenzoate with various other classes of compounds in the presence of catalytic amounts of copper ions produce benzoyloxy derivatives. Thus this reaction can also be used to effect one-step oxidation of saturated hydrocarbons,9, 10 esters,6,11 dialkyl and aryl alkyl ethers,12 14 benzylic ethers,11,15 cyclic ethers,13,16 straight-chain and benzylic sulfides,12, 17-19 cyclic sulfides,11,19 amides,11 and certain organo-silicon compounds.20... 

Transparent vitreous sihca is made by electric melting of natural quartz minerals such as sand in vacuum. It also may be made by fusing quartz in flame or by vapor phase hydrolysis or oxidation of pure silicon compounds by heating electrically or using a flame or plasma. Translucent form is made by fusion of high purity quartz sand crystals. 

Deposition profile was then followed by an infrared study. Deposition of silicon alkoxlde removed Isolated sllanol at 3745 cm selectively, while that of hydrogen-bonded at 3600 cm was kept unaltered, as shown in Fig. 2a, b. Methyl group of surface residue of silicon compound was seen simultaneously with the disappearance of isolated sllanol. Upon reaction of the surface deposited species with water, the stretch bands of the methyl group disappeared, and the absorption of Isolated sllanol was recovered completely or incompletely, depending upon the kind of zeolite and metal oxide. 

Acohols - [ALCOHOL FUELS] (Vol 1) - [FEEDSTOCKS-COALCHEMICALS] (Vol 10) - [DISTILLATION, AZEOTROPIC AND EXTRACTIVE] (Vol 8) - [COALCONVERSIONPROCESSES - LIQUEFACTION] (Vol 6) - [FLAME RETARD ANTS - PHOSPHORUS FLAME RETARD ANTS] (Vol 10) - [EXPLOSIVES AND PROPELLANTS - PROPELLANTS] (Vol 10) -as antifreeze [ANTIFREEZES AND DEICING FLUIDES] (Vol 3) -for automotive motor fuel [FUELS, SYNTHETIC - LIQUID FUELS] (Vol 12) -from castor oil [CASTOR OIL] (Vol 5) -in ceramic processing [CERAMICS - CERAMIC PROCESSING] (Vol 5) -from hydrocarbon oxidation [HYDROCARBON OXIDATION] (Vol 13) -as hypnotic and sedative [HYPNOTICS, SEDATIVES, ANTICONVULSANTS, AND ANXIOLYTICS] (Vol 13) -m metal polishes [POLISHES] (Vol 19) -from oxo process [OXO PROCESS] (Vol 17) -permanganate oxidation [MANGANESE COMPOUNDS] (Vol 15) -reactions with silanes [SILICON COMPOUNDS - SILANES] (Vol 22) -role m mineral processing [MINERALS RECOVERY AND PROCESSING] (Vol 16)... 

Gngnard reagents - [BROMINE COMPOUNDS] (Vol 4) - [ESTERS, ORGANIC] (Vol 9) -from benzene [BENZENE] (Vol 4) -chemiluminescence [LUMINESCENTMATERIALS - CHEMILUMINESCENCE] (Vol 15) -magnesium alkyls from [MAGNESIUM COMPOUNDS] (Vol 15) -reaction of propylene oxides [PROPYLENE OXIDE] (Vol 20) -for silanes [SILICON COMPOUNDS - SILANES] (Vol 22) -for sulfoxide synthesis [SULFOXIDES] (Vol 23)... 

The choice of substituents is of crucial importance for the successful synthesis and isolation of polyhedral silicon compounds. The Si—Si bonds of the small-ring compounds are readily oxidized because of the existence of high-lying orbitals and their inherent high strain. Therefore, the full protection of the skeleton by bulky substituents is required to suppress the attack by external reagents. 

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