Abstract: Polyisocyanurate/polyisocyanates of enhanced stability are prepared by partial catalytic cyclotrimerization of a polyisocyanate in the presence of a catalytically effective amount of an aminosilyl catalyst and wherein the cyclotrimerization reaction is terminated when a predetermined desired amount of isocyanurate groups has been attained, by adding to the reaction mixture, after the cooling thereof to a temperature of below 50.degree. C., a reaction terminating amount of an organic catalyst deactivating compound comprising at least one free hydroxyl moiety, or the reaction product of such hydroxylated organic catalyst deactivating compound with an isocyanate.

Abstract: A catalyst support and process for preparing same are provided wherein a metal substrate is coated with a layer of adherent alumina with a layer of chromium interposed between the alumina catalyst support and the metal substrate. The catalyst supports of the invention are especially useful in catalytic converters for the purification and control of exhaust gas emissions from internal combustion engines by the active catalyst oxidation/reduction of carbon monoxide, unburned hydrocarbons and nitrogen oxides.

Abstract: Noncrystallizable single-component organopolysiloxane compositions which are storage-stable in the absence of water, curable into elastomers at ambient temperatures and above in the presence of water, and which are well adopted for the production of silicone coatings and seals, include:(A) at least one .alpha.,.omega.-dihydroxydiorganopolysiloxane polymer;(B) a methyltriacetoxysilane cross-linking agent therefor; and(C) an effective amount of at least one additive for preventing the crystallization of said cross-linking agent (B), miscible therewith in all proportions and liquid at ambient temperature, said additive comprising:(i) a diester of ortho-phthalic acid with a monoalcohol of the formula GOH, wherein G is a hydrocarbon radical containing from 4 to 12 carbon atoms; or(ii) an ester of acetic acid with a monoalcohol of the formula G'OH, wherein G' is hydrocabon radical containing from 6 to 18 carbon atoms.

Abstract: Novel RTV organopolysiloxane compositions, advantageously two-component compositions, which are easily vulcanized into self-adhesive elastomers having excellent reversion properties, are comprised of (1) at least one alpha, omega-dihydroxydiorganopolysiloxane polymer having a viscosity of from about 500 to 1,000,000 mPa.s at 25.degree. C., the organic radicals of which being monovalent hydrocarbon radicals, (2) at least one filler material therefor, (3) at least one polyalkoxysilane or polyalkoxysiloxane cross-linking agent therefor, (4) a catalytically effective amount of at least one tin catalyst, and (5) at least one silane having the general formula: ##STR1## wherein R is an alkyl or alkoxy radical having from 1 to 4 carbon atoms, at least 2 of said radicals R being alkoxy radicals, R' is an alkyl radical having from 1 to 3 carbon atoms, and n is an integer of from 3 to 10.

Abstract: A phase contactor is provided with guide means along the path of flow of the vertically descending current of first gaseous phase established therein, but upstream of the zone of restricted flow passage, the guide means being adapted to adjust the flow of the first gaseous phase and to retard/prevent the deposition of objectionable encrusting solids within the phase contactor.

Abstract: A process for the preparation of compounds containing a difluoromethylene or trifluoromethyl group. A compound containing a carbonyl group, preferbly an acid, acid halide, amide, ketone or any compound containing a perhaloalkylcarbonyl moiety is placed, in anhydrous liquid hydrofluoric acid, in contact with boron trifluoride in a quantity such that the absolute pressure of boron trifluoride in the reaction system is at least one bar for a time sufficient to convert the carbonyl group to a difluormethylene or trifluoromethyl group.The compounds obtained are useful as synthesis intermediates in the pharmaceutical, plant-protection and dye industries, as anesthetics or as heat-transfer and lubricating fluids.

Abstract: Aqueous solutions of polysaccharide biopolymers, e.g., Xanthomonas/carbohydrate fermentation worts, are heat treated for more than 5, but less than 60 minutes, at a pH ranging from 3.5 to 6.2, to improve the viscosifying, filterability and injectability properties thereof, and are well adapted, e.g., for secondary and tertiary hydrocarbon (petroleum) recovery by waterflooding therewith.

Abstract: A powder of elemental silicon having high purity and a density in excess of about 0.6 g/cm.sup.3, preferably ranging from 0.8 to 1.2 g/cm.sup.3, and which is non-amorphous as determined by X-ray analysis, is facilely prepared by thermally decomposing a silane feedstream at a decomposition reaction temperature ranging from 500.degree. to 700.degree. C., preferably from 500.degree. to 600.degree. C.

Abstract: Dimethyldichlorosilane is directly prepared from methyl chloride and silicon, in high productivity, selectivity and degree of silicon conversion, by reacting methyl chloride with a solid contact mass comprising silicon and a catalytically effective amount of a catalyst which includes (1) elemental copper or a copper compound, (2) from about 30 to 1,000 ppm (calculated as metallic tin and/or antimony) of at least one of the metals tin and antimony, or at least one compound of at least one of the metals tin and antimony, and (3) from about 0.05 to 4% by weight, (calculated as cesium metal) of cesium or a cesium compound, or admixture of cesium with up to 90% by weight of the admixture of lithium, sodium, potassium or rubidium, the amounts of said components (2) and (3) being based upon the total weight of said solid contact mass.

Abstract: Process/apparatus for electrolytically oxidizing solutions of ionic compounds features the electrolytic oxidation of such solutions in a first anode compartment of an electrolytic cell, said electrolytic cell further comprising a second anode compartment, a cathode compartment, and a pair of cationic membranes respectively separating said cathode compartment from said first and second anode compartments; transferring a portion of said solution electrolytically oxidized in said first anode compartment to said second anode compartment and there continuing the electrolytic oxidation thereof; and then recovering product of electrolytic oxidation from said second anode compartment.

Abstract: A process for the thermal treatment of a polysilazane at a temperature from about 40.degree. C. to 220.degree. C. The polysilazane contains on average at least two, preferably at least three, .tbd.SiH groups per molecule and at least two ##STR1## groups and, if appropriate, unsaturated aliphatic hydrocarbon groups bonded to the silicon atoms. The polysilazanes treated in this manner have good thermal behavior and can be used in particular as precursors of ceramic products with a high yield of inorganic products.

Abstract: A process for preparing hydroxylated aromatic compounds optionally bearing at least one trifluoromethyl, trifluoromethoxy or trifluoromethylthio group. A chloroformate or fluoroformate, optionally bearing at least one trihalomethyl-, trihalomethoxy- or trihalomethylthiophenyl group, is reacted with liquid hydrofluoric acid.The aromatic compounds obtained are useful as synthesis intermediates in the pharmaceutical or the plant-protection industry.

Abstract: Dimethyldichlorosilane is directly prepared from methyl chloride and silicon, in high productivity, selectivity and degree of silicon conversion, by reacting methyl chloride with a solid contact mass comprising silicon and a catalytically effective amount of a catalyst which includes (1) elemental copper or a copper compound, (2) from about 30 to 1,000 ppm (calculated as metallic tin and/or antimony) of at least one of the metals tin and antimony, or at least one compound of at least one of the metals tin and antimony, and (3) from about 0.05 to 2% by weight, (calculated as alkali metal) of at least one of the alkali metals lithium, sodium, potassium and rubidium, or compound thereof, the amounts of said components (2) and (3) being based upon the total weight of said solid contact mass.

Abstract: Storage-stable, adhesive, flexible and mechanically improved thermosetting film-forming compositions are comprised of (A) an imido-hydroxylated organosilicon prepolymer, (B) triallyl isocyanurate or an acrylic ester of a diphenylated siloxane, (C) an imidazole, and (D) an N,N',N"-tris(hydroxyalkyl)hexahydrotriazine.

Abstract: A process for the preparation of 1,1-dichloro-2,2,2-trifluoroethoxybenzene derivatives or 1,1-dichloro-2,2,2-trifluoroethylthiobenzene derivatives. A 2,2,2-trifluoroethoxybenzene or a 2,2,2-trifluoroethylthiobenzene derivative is brought into contact with chlorine in the presence of radiation.

Abstract: An improved oxidation catalyst, well adopted for the conversion of H.sub.2 S-containing acid gases at least in part to elemental sulfur, is facilely prepared by (i) hydrothermally treating at least a portion of an active alumina support, and (ii) then impregnating said at least partially hydrothermally treated support with a catalytically effective amount of a catalytically active oxide phase which comprises the oxides of at least one of the metals, Fe, Cu, Ag, W, Co, Ni, Bi, Cr and Cd, with the proviso (iii) that at least one rare earth oxide, alkaline earth metal oxide, zirconium oxide or silica compound, or any precursor compound thereof, is incorporated into the catalyst during either of the steps (i) or (ii).

Abstract: Gelation-resistant, high pot life organopolysiloxane compositions adapted for antiadhesive/release coating applications, are comprised of (1) at least one substantially straight-chain organopolysiloxane having a viscosity ranging from about 50 to 100,000 mPa.s at 25.degree. C. and containing at least x alkenyl unsaturated hydrocarbon groups bonded to a silicon atom, per molecule, wherein x.gtoreq.2, (2) at least one organohydropolysiloxane crosslinking agent having a viscosity ranging from about 10 to 100,000 mPa.s at 25.degree. C. and containing at least y hydrogen atoms bonded to silicon atoms, per molecule, wherein y.gtoreq.2, (3) a catalytically effective amount of a platinum group metal crosslinking catalyst, and (4) an effective amount of at least one azodicarboxylate gelation inhibitor which is inert to the activity of said catalyst (3), but in insufficient amount as to prevent the crosslinking of said polysiloxanes (1) and (2) under crosslinking conditions.

Abstract: Novel alloys comprising neodymium, iron and optionally another rare earth metal are facilely prepared by reducing a neodymium/rare earth halide with a reducing metal, in the presence of iron.

Abstract: Organopolysiloxane compositions adopted for easy conversion into burn resistant foams useful, e.g., for the protection of nuclear power installations, include admixture of various organopolysiloxane polymers comprising SiH, SiOH, SiR.sub.3 and Si-vinyl functions, and notably a hydroxylated liquid resin containing CH.sub.3 SiO.sub.1.5 and (CH.sub.3).sub.2 SiO units, or reaction product of a hydroxylated MQ resin with a hydroxylated polyorganosiloxane oil, or mixture thereof.

Abstract: Hydrogenosilanes, notably the monosilanes, are conveniently prepared by reducing a halogenosilane with an alkali or alkaline earth metal hydride, typically in a solvent reaction medium, in the presence of a catalytically effective amount of a sequestering agent having the general formula: ##STR1##