Abstract: A process for the catalytic treatment of a polysilazane containing an average of at least two, preferably at least three, .tbd.SiH groups per molecule with a catalytically effective quantity of a strong inorganic or organic acid catalyst. The other organic radicals in the polysilazane that are bonded to the silicon or nitrogen atoms are hydrocarbon radicals free from alkene or alkyne unsaturations. The polysilazanes treated in this manner can be characterized by good thermal behavior and can be used, in particular, as precursors of ceramic products with a high yield of inorganic products.

Abstract: Process for preparing alkyl alkoxyalkylidenemalonate. An alkyl malonate is condensed with an orthoester in the presence of a carboxylic acid or its anhydride and a metal compound of the group formed by Cd, Hg, Bi, Mg.

Abstract: Novel organotin curing catalysts for, e.g., the RTV organopolysiloxanes, whether single- or two-component such compositions, are comprised of admixture of (i) a diorganotin bis(.beta.-diketonate) and (ii) an organotin (IV) compound devoid of .beta.-diketonato functional group. The silicone elastomers produced thereby are notably well adopted for use in the building industry.

Abstract: Precipitation silicas, in the form of aggregates as shown in FIG. 1, having a mean projected area of the aggregates which is higher than about 8,000 nm.sup.2 and preferably is higher than about 15,000 nm.sup.2. The present invention also concerns a process for the production of precipitation silica by maintaining a constant-volume reaction medium to provide suitable colloids of silica, reacting the colloids with an electrolyte and consolidating the resulting product by the addition of a solution of silicate and an acidifying agent to obtain a precipitation silica.

Abstract: Trichlorosilane, SiHCl.sub.3, is facilely prepared by (i) thermally reducing silicon tetrachloride, SiCl.sub.4, with hydrogen to produce reaction admixture comprising SiHCl.sub.3 and hydrochloric acid, said thermal reduction being carried out in a thermal plasma while tempering the reaction medium with a cooling gas, (ii) reacting said step (i) reaction admixture with elemental silicon at a temperature of from about 250.degree. to 350.degree. C. to produce SiHCl.sub.3 and hydrogen therefrom, and thence (iii) separating (iiia) the plasma-creating, hydrogen and cooling gases, and (iiib) product silicon chlorides therefrom.

Abstract: A process for the preparation of (pentafluoroethoxy)- and (pentafluoroethylthio)benzene derivatives either from phenol, thiophenol or from halobenzene. A halobenzene is reacted with trifluoroethanol or a phenol or a thiophenol is reacted with a compound of the formula CF.sub.3 --CH.sub.2 --O--R'. The product is chlorinated and the chlorinated product is fluorinated in liquid hydrofluoric acid in the presence of a Lewis acid.The compounds obtained by the process of the present invention are used as synthesis intermediates in the phytosanitary, pharmaceutical and veterinary industries, and are used in lubricants.

Abstract: Shaped articles, e.g., bars, of semiconductor-grade, ultra-pure silicon, are facilely and efficiently produced by thermally decomposing/pyrolyzing a monosilane feedstream on a red-heated silicon support member, whereby high purity silicon is deposited thereon, and thence recycling the majority of the by-product reaction admixture into said monosilane feedstream.

Abstract: Essentially pure salicylic acid crystals, typically containing less than 0.01% inorganic salt, less than 0.01% para-hydroxybenzoic and 4-hydroxyisophthalic acid and well adopted for foodstuff and pharmaceutical applications, are facilely recovered from an aqueous solution of sodium salicylate by (i) adding an organic solvent for salicylic acid to such aqueous solution, in an amount sufficient to dissolve the salicylic acid corresponding to said sodium salt thereof, (ii) next adding thereto an at least stoichiometric amount, relative to said sodium salicylate, of a strong inorganic acid, and (iii) separating therefrom an essentially organic phase which comprises said salicylic acid and an aqueous phase which comprises an inorganic sodium salt.

Abstract: An improved fluorinated siliceous catalyst, well adapted for the catalytic synthesis of aromatic/aliphatic nitriles from their corresponding formamides, formanilides or amides, is comprised of a plurality of silica particulates, the specific surface of which ranging from about 200 to about 300 m.sup.2 /g, having a total pore volume ranging from about 1 to about 1.5 cm.sup.3 /g, with an average pore diameter ranging from about 100 to about 200 .ANG., having an exchange pH of less than about 3, and with the fluorine content thereof bonded to the silica, expressed in F.sup.31 , ranging from about 0.05 to about 2% by weight based upon the silica, and the sodium content thereof, expressed as Na.sub.2 O, being less than about 1% by weight, also based upon the silica.

Abstract: Stannous salts of a non-oxidizing anionic acid, e.g., stannous fluoborate or stannous sulfate, are prepared by reacting metallic tin with a preferably aqueous solution of such acid in the presence of a catalytically effective amount of finely divided catalyst particles, e.g., comprised of a precious metal, said catalyst particles providing hydrogen release at low overvoltages.

Abstract: Essentially pure para-hydroxybenzoic acid crystals, typically containing but trace amounts of inorganic potassium salts and salicylic or 4-hydroxyisophthalic acid, well adopted for foodgrade applications, are facilely recovered from an aqueous solution of dipotassium and/or monopotassium para-hydroxybenzoate by (i) adding an organic solvent for para-hydroxybenzoic acid to such aqueous solution, in an amount sufficient to dissolve the para-hydroxybenzoic acid corresponding to said potassium salts thereof, (ii) next adding thereto an at least stoichiometric amount, relative to said dipotassium and/or monopotassium salt of para-hydroxybenzoic acid, and (iii) separating therefrom an essentially organic phase which comprises said para-hydroxybenzoic acid and an aqueous phase which comprises an inorganic potassium salt.

Abstract: Stable, gel-forming aqueous microemulsions, well adopted for the reversible stabilization or plugging of soil/rock formations, e.g., subterranean well formations, are comprised of (i) an aqueous solution of a water-soluble alkali metal silicate, (ii) a gelling reagent therefor, and (iii) at least one surface active agent.

Abstract: The present invention provides a cationic latex of copolymers based on conjugated dienes, formed by the steps of preparing an aqueous dispersion of particles by reacting at least one unsaturated tertiary nitrogen compound not capable of being hydrolyzed in an acid or alkaline medium with an aqueous emulsion reaction medium, containing cationic species, of at least one non-ionic monomer capable of being copolymerized with the non-hydrolyzable unsaturated nitrogen compound to form synthetic polymers and at least one substance which generates cationic species capable of chemically binding with the synthetic polymers; the non-ionic monomer being converted to polymer in the reaction in a degree of up to at least about 30%; and polymerizing, in the aqueous dispersion, at least one conjugated diene or a mixture of conjugated dienes and at least one non-ionic monomer in the presence of an initiator selected from the group consisting of an uncharged initiator and a cationic charge-generating initiator.

Abstract: A fine powder of stabilized zirconia a process for its preparation and application of the powder in ceramic compositions to obtain good mechanical, thermomechanical and electrical properties.A zirconia hydrate sol having a pH between 0.5 and 5 and containing elementary acicular crystals having dimensions of from about 10 to 500 .ANG. which are agglomerated into submicron aggregates of from abuot 100 to 5000 .ANG. in diameter is mixed with a solution of a stabilizing agent, preferably yttrium; the suspension is dried; the dried suspension is calcined at a temperature of from about 700.degree. C. to 1,300.degree. C. for preferably from about 30 minutes to 24 hours; and if needed, the powder obtained is milled.

Abstract: Novel N-(meth)allyloxyphenylmaleimides are prepolymerized with at least one bis-imide and formulated, together with at least one imidazole compound, into thermosetting compositions useful for the production of a wide variety of shaped articles having improved mechanical properties.

Abstract: Glass polishing compositions, advantageously recycled into glassmaking formulations, are comprised of suspension of particulate ceric oxide and at least one colorless oxide of a lanthanide or yttrium rare earth, preferably an oxide of lanthanum, samarium, europium, gadolinium, dysprosium, thulium, ytterbium, lutecium, yttrium, or mixtures thereof.

Abstract: Heat-vulcanizable organopolysiloxane compositions, adopted for curing into silicone elastomers having improved reversion and oil resistance and useful, e.g., as seals in contact with hot oils, comprise at least one diorganopolysiloxane resin (A) having a viscosity of greater than 1,000,000 mPa.s at 25.degree. C., a reinforcing and/or semireinforcing filler material (B), an organic peroxide (C), an organosilicon compound (D) containing at least one acryloyloxyalkyl or methacryloyloxyalkyl group bonded to a silicon atom, and (E) at least one oxide or hydroxide of an alkaline earth metal.

Abstract: Aqueous solutions of polysaccharide biopolymers, e.g., Xanthomonas/carbohydrate fermentation worts, are treated with mutanase-containing enzymes to improve the filterability and injectability thereof, and are well adapted, e.g., for secondary and tertiary hydrocarbon (petroleum) recovery by waterflooding therewith.

Abstract: Method of spinning fibers and coating from an organopolysilazane composition that can be crosslinked by an energy input. The organopolysilazane composition comprises an organopolysilazane and a free radical generator in an amount effective to crosslink the organopolysilazane. The energy input capable of generated the radical may be provided in the form of heat, ultraviolet radiation, an electron beam, and the like.The crosslinked organopolysilazane compositions exhibit good thermal behavior and, in particular, can be used, after pyrolysis, as precursors of ceramic products.

Abstract: Durable, aging-resistant alumina-based catalyst carriers having improved mechanical strength are facilely prepared by (i) impregnating an alumina-based catalyst carrier with an aqueous solution of a quaternary ammonium silicate, (ii) drying said impregnated carrier, and (iii) calcining said dried carrier.