Silicon powder

Silicon, like carbon, is unaffected by dilute acids. Powdered silicon dissolves incompletely in concentrated nitric acid to give insoluble silicon dioxide, SiOj ... 

The hydrocarbon can be in either the liquid or vapour phase and the silicon is finely divided. The inclusion of certain solid catalysts in the reactive mass may in some instances greatly facilitate the reaction. A mixture of powdered silicon and copper in the ratio 90 10 is used in the manufacture of alkyl chlorosilanes. 

In the case of phenylchlorosilanes some modifications are made to the process. Chlorobenzene is passed through the reaction tube, which contains a mixture of powdered silicon and silver (10% Ag), the latter as catalyst. Reaction temperatures of 375-425°C are significantly higher than for the chloro-methylsilanes. An excess of chlorobenzene is used which sweeps out the high boiling chlorophenysilanes, of which the dichlorosilanes are predominant. The unused chlorobenzene is fractionated and recycled. 

Powdered silicon can combust when water is present. It creates suspensions in air, which detonate violently when there is an ignition source present. The silicon/lithium alloy can combust spontaneously in air. 

Finely powdered silicon can give significant dust explosion hazards. Relationships of sensitivity to spark ignition and of explosibility to particle size are studied [1]. Maximum explosion pressures of 6.4 bar, with maximum rate of rise of 884 bar/s have been determined [2], Silicon dust is likely to result from processes using silanes in the gas phase [3],... 

Glucose oxidase, one of the most widely used enzymes for constructing biosensors, was employed by Matuscewski and Trojanowicz to develop a biosensor based on a mixture of graphite powder, silicone oil and the biocatalyst. The paste thus obtained was placed in a slot of the PTFE end... 

Silicon and lead oxide Mixtures of powdered silicon and lead oxide/lead dioxide/red lead burn fiercely and rapidly with the formation of metallic lead and fusible lead silicate. The reactions may be shown in Equation 5.9 ... 

The alkyl- or aryl-halogenosilanes are prepared commercially by passing the vapour of an alkyl or an aryl halide over a heated intimate mixture of powdered silicon and either copper or silver. 

Collect a little of a mixture of anhydrous potassium carbonate and sodium carbonate (the mixture melts more easily than either salt alone) in a loop on the end of a platinum wire and melt it in the Bunsen flame to a clear bead. Dip the bead into powdered silicon dioxide and melt it again. Note that the liquid bead effervesces until the silica has dissolved. 

The actual operation of the direct method involves heating a mass of powdered silicon (preferably associated with a catalyst) in... 

Note The remainder of the composit consisted of 80 wt% filler consisting of barium- aluminum-boron silicate glass powder, silicon dioxide-zirconium dioxide, and ytterbium fluoride. For dental composites lower viscosities are preferred because of their flowability. 

Reaction of Silicon on Solutions of Alkali Hydroxides. This method is based on the reaction of a concentrated solution of sodium hydroxide on powdered silicon or ferrosilicon, where hydrogen and a solution of sodium silicate are the products of the reaction ... 

To produce silicon nitride powder, silicon can be nitridated at elevated temperatures in an atmosphere of nitrogen or ammonia ... 

Derivation Reaction of powdered silicon and ethyl chloride at 300C, in presence of copper powder. Grade Technical. 

Derivation (1) Reaction of powdered silicon and chlorobenzene in the presence of copper powder as catalyst (2) reaction of phenylmagnesium chloride with silicon tetrachloride. 

Docekal B. and Krivan V. (1992) Direct determination of impurities in powdered silicon carbide by electrothermal atomic absorption spectrometry using the slurry sampling technique, J Anal At Spectrom 7 521-528. 

The use of synthetic zeolites as selective cracking materials in the petroleum and oil refinery industries has increased dramatically during the past 25 years. Powdered silicon carbide has increasingly been used as a basic material for the production of... 

RTP produces series of engineering thermoplastics lubricated with PTFE, molybdenum disulfide, graphite powder, silicone and glass, carbon and aramid fibers. Grades AR, TEE and SI include respectively aramid fibers, PTFE (10-20%) and silicone fluid (0.5%). Matrix materials used include PA-6, PA-66, PA-6,10, PA-12, PC, POM, PET, PBT, PSF, PPS, PEI, PEEK and polyphthalamide. The blends have been developed for injection molding of various parts for engineering applications. 

Powdered silicon is heated in a 2 1 mixture (by volume) of Clg and Oi3, using the same apparatus as for the preparation of SiCl. Both the gases and the apparatus must be carefully dried. The Og is introduced first, and then the Cl 3 flow is started. It is best not to rely upon the observation of gas bubbles in the wash bottles for... 

Other preparative possibilities Passage of dry H2S over powdered silicon at 1200 - 1300°C. 

Boiling point, 2230 Melting point, 1610 Relative density (water-1) 2.6 Solubility In water none Relative molecular mass 60.1 Grossformula 028 WHITE POWDER Silicon dioxide is a component of among others, sand, granite, scouring powder and day. ... 

Trichlorosilane (SiHCls, silicochloroform) [10025-78-2] M 135.4, m -126°, b 31,8 /atm, 32-34 /atm, 36.5°/atm, d 1.342, n p 1.4020. This volatile trichlorosilane can be obtained from silane and HCl in the presence of AICI3, and is purified by fractional distillation at atmospheric pressure in the strict absence of moisture. However, S1HCI3 is best prepared by placing finely powdered silicon (purified by boiling with HCl... 

---