Abstract: This invention provides a process of preparing reaction-derived decahalodiphenylethane of high purity. The process comprises cofeeding separate feeds of (a) diphenylethane and (b) bromine chloride, bromine chloride and bromine, or bromine chloride and chlorine to a refluxing reaction mixture comprising bromine and at least one Lewis acid bromination catalyst so that high purity decahalodiphenylethane is formed.

Abstract: The process features concurrent feeds into the liquid phase of a prepolymerization reaction mixture. These feeds are: a) separate continuous or substantially continuous feeds of (i) a polymerizable vinylolefin, and (ii) a solution in an organic liquid solvent of a metallocene and an aluminoxane and/or metallocene-aluminoxane reaction product; or b) separate continuous or substantially continuous feeds of (i) a polymerizable vinylolefin, (iii) a metallocene optionally in an organic liquid solvent or diluent, and (iv) an aluminoxane optionally in an organic liquid solvent or diluent; or c) separate continuous or substantially continuous feeds of (i) and (ii) and at least one of (iii) and (iv). Particles of catalytically-active, prepolymerized, self-supported olefin polymerization catalyst composition are formed in the reaction medium. The metallocene used as the feed or in making up the feed has at least one polymerizable olefinic substituent in the molecule.

Abstract: A mixture comprised of about 60-85% of 2,4-toluenediamine (2,4-TDA) and about 15-40% of 2,6-toluenediamine (2,6-TDA) is melted, the temperature of the mixture is lowered to a 2,4-TDA nucleation temperature, and the temperature of the mixture is gradually reduced from the nucleation temperature to about 65 to about 70° C. The resultant mixture is in the form of a solids phase enriched in 2,4-TDA, and a novel and useful liquid phase enriched in 2,6-TDA. These phases are separated. Preferably the solids are further purified by “sweating” them and removing the sweated liquid impurities. The sweated liquid can be recycled together with another charge of a mixture comprised of 2,4-TDA and 2,6-TDA. 2,4-TDA can be produced with a purity of 96-99%.

Abstract: A highly efficient method of producing alkyl mercaptan and/or dialkyl monosulfides which involves employing carbon dioxide as an internal coolant is described. Only negligible amounts of carbonyl sulfide were formed. In addition, relatively easy separation of carbon dioxide from the reaction mixture facilitates an efficient coolant recycle process, giving a simple and effective mode of temperature control.

Abstract: A cleaning process suitable for both mild and aggressive applications employs non-flammable, non-corrosive and environmentally friendly, fluorinated hydrobromocarbon solvent based cleaning compositions.

Abstract: A process for cleaning movie film, and especially cellulose acetate based polymer film, without causing film damage, comprises immersing the film into a cleaning solvent composition which comprises one or more halogenated hydrobromocarbons having from 1 to 3 carbons, from 1 to 3 bromine atoms and at least one chlorine or fluorine atom, such as 3-bromo-1,1,1-trifluoropropane, removing the film from the solvent and drying the film.

Abstract: The hydrogen content of polysilicon can be reduced by heat treatment. The process is preferably conducted on polysilicon particles in bead-like form produced by chemical vapor deposition in a fluidized bed. The heat treatment is preferably conducted at a temperature of 1020.degree.-1200.degree. C. for a time from about 6 hours to about 1 hour sufficient to reduce the hydrogen content, and insufficient to cause agglomeration of the particles being treated. In order to reduce the tendency of particles to agglomerate at the process temperature employed, the particle bed is preferably maintained in motion during the dehydrogenation. The products produced by the process can have a hydrogen content of 30 ppma or less. These improved products can be used to produce monocrystalline silicon for the production of semiconductor devices.

Abstract: The hydrogen content of polysilicon can be reduced by heat treatment. The process is preferably conducted on polysilicon particles in bead-like form produced by chemical vapor deposition in a fluidized bed. The heat treatment is preferably conducted at a temperature of 1020.degree.-1200.degree. C. for a time from about 6 hours to about 1 hour sufficient to reduce the hydrogen content, and insufficient to cause agglomeration of the particles being treated. In order to reduce the tendency of particles to agglomerate at the process temperature employed, the particle bed is preferably maintained in motion during the dehydrogenation. The products produced by the process can have a hydrogen content of 30 ppma or less. These improved products can be used to produce monocrystalline silicon for the production of semiconductor devices.

Abstract: An apparatus and process for maintaining the purity of solid/granular product and dispensing high purity granular product from a vessel. A noncontaminating surface is provided by a cup, cylinder, or other structure having a surface of silicon, silicon carbide, silicon nitride, sialon, or similar materials and preferably operates as an angle of repose valve in a pressurized system to prevent contamination by undue contact of the high purity product with conventional gastight valves such as ball valves, butterfly valves, pinch valves, etc.

Abstract: An apparatus and process for maintaining the purity of solid/granular product and dispensing high purity granular product from a vessel. A noncontaminating surface is provided by a cup, cylinder, or other structure having a surface of silicon, silicon carbide, silicon nitride, sialon, or similar materials and preferably operates as an angle of repose valve in a pressurized system to prevent contamination by undue contact of the high purity product with conventional gastight valves such as ball valves, butterfly valves, pinch valves, etc.

Abstract: A process for continuously preparing silane and a coproduct by reacting a metal hydride such as NaAlH.sub.4 with a silicon halide such as SiF.sub.4, utilizing, in conducting the reaction, equipment which includes, in series, a primary reactor, a secondary reactor and a separation zone. The metal hydride is reacted in the first reactor with less than a stoichiometric amount of the silicon halide, and the unreacted metal hydride is then passed to the second reactor wherein the remainder of the hydride is reacted in the secondary reactor, in which a stoichiometric excess of the silicon halide is added. The rate of silicon halide or metal hydride addition is governed by a temperature differential feed back from the reaction in the secondary reactor so that overall a stoichiometric or substantially stoichiometric operation is achieved.

Abstract: An apparatus and process for maintaining the purity of solid/granular product and dispensing high purity granular product from a vessel. A noncontaminating surface is provided by a cup, cylinder, or other structure having a surface of silicon, silicon carbide, silicon nitride, sialon, or similar materials and preferably operates as an angle of repose valve in a pressurized system to prevent contamination by undue contact of the high purity product with conventional gastight valves such as ball valves, butterfly valves, pinch valves, etc.

Abstract: An apparatus for maintaining the purity of solid/granular product and dispensing high purity granular product from a vessel. A noncontaminating surface is provided by a cup, cylinder, or other structure having a surface of silicon, silicon carbide, silicon nitride, sialon, or similar materials and preferably operates as an angle of repose valve in a pressurized system to prevent contamination by undue contact of the high purity product with conventional gastight valves such as ball valves, butterfly valves, pinch valves, etc.