Patents Assigned to Rhone-Poulenc Specialites Chimiques
  • Continuous production of lithium metal by electrolysis of lithium chloride
    Patent number: 4724055
    Abstract: Lithium metal is continuously prepared, in specially adapted electrolytic cell, by (i) continuously electrolyzing a mixture of molten salts including lithium chloride, said mixture comprising the medium of electrolysis, (ii) continuously withdrawing admixture of product lithium metal with said mixture of molten salts, and (iii) continuously discharging formed chlorine gaseous phase therefrom, wherein the medium of electrolysis is maintained at a temperature ranging from the melting point of said mixture of molten salts, at the eutectic composition thereof, to 400.degree. C., and said gaseous chlorine phase is maintained at a temperature not exceeding 300.degree. C.
    Type: Grant
    Filed: December 15, 1986
    Date of Patent: February 9, 1988
    Assignee: Rhone-Poulenc Specialites Chimiques
    Inventors: Eric Le Roux, Philippe Nataf, Serge Jacubert
  • Nitration of phenolic compounds
    Patent number: 4723043
    Abstract: Substituted phenols are nitrated by contacting same with a 10 to 70% by weight concentrated aqueous solution of nitric acid. The subject nitration process is well adopted for the preparation, e.g., of 2,6-dichloro-4-nitrophenol, a valuable intermediate in the production of various agrochemicals/pharmaceuticals.
    Type: Grant
    Filed: July 7, 1986
    Date of Patent: February 2, 1988
    Assignee: Rhone-Poulenc Specialites Chimiques
    Inventor: Serge Ratton
  • Organopolysilazane composition containing free radical generators and capable of being crosslinked by an energy input
    Patent number: 4722988
    Abstract: 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 generating 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.
    Type: Grant
    Filed: May 6, 1986
    Date of Patent: February 2, 1988
    Assignee: Rhone-Poulenc Specialites Chimiques
    Inventors: Hugues Porte, Jean-Jacques Lebrun
  • Process for the preparation of aromatic aldehydes
    Patent number: 4720594
    Abstract: Process for the preparation of aromatic aldehydes by hydrocarbonylation of chloro- or bromoaromatic compounds. In the presence of an acceptor for an oxygen-free acid, a palladium/phosphine complex and, if appropriate, a phosphine, a mixture of carbon monoxide and hydrogen is reacted with chloro- or bromoarenetricarbonylchromiums.
    Type: Grant
    Filed: June 13, 1986
    Date of Patent: January 19, 1988
    Assignee: Rhone-Poulenc Specialites Chimiques
    Inventors: Jean-Marie Basset, Robert Mutin
  • Block copolyetheramides flexible at low temperatures
    Patent number: 4717763
    Abstract: Homogeneous, flexible block copolyetheramides having a melting/softening point of at least 170.degree. C., a glass transition temperature, measured at ZHE, of at most -5.degree. C.
    Type: Grant
    Filed: December 11, 1985
    Date of Patent: January 5, 1988
    Assignee: Rhone-Poulenc Specialites Chimiques
    Inventors: Jean Coquard, Jean Goletto
  • Novel spheroidal silica particulates
    Patent number: 4704374
    Abstract: Mechanically strong, H.sub.2 O-stable, macroporous spheroidal silica particulates, well adopted as catalysts/catalyst supports, are produced by (i) granulating and agglomerating a particular hydrosol of silica with a particular silica xerogel or aerogel, and (ii) drying the resultant silica particulates.
    Type: Grant
    Filed: July 15, 1986
    Date of Patent: November 3, 1987
    Assignee: Rhone-Poulenc Specialites Chimiques
    Inventor: Roland Jacques
  • Mixed polyester molding compositions
    Patent number: 4704417
    Abstract: Mixed polyester molding compositions comprising at least a pair of structurally different thermoplastic polyesters are stabilized against transesterification, whether during formulation or the downstream molding thereof, by having incorporated therein an effective amount of at least one mono-, di- or triester of orthophosphoric acid.
    Type: Grant
    Filed: July 5, 1985
    Date of Patent: November 3, 1987
    Assignee: Rhone-Poulenc Specialites Chimiques
    Inventors: Yves Bonin, Michel Logeat
  • Semi-permeable membrane structure that is particularly suitable for plasmapheresis
    Patent number: 4702835
    Abstract: A semi-permeable membrane structure that is particularly adapted for plasmapheresis includes a frame having two tubes each forming an internal conduit opening inside the frame, and a membrane on either side of the frame, each membrane being mounted with its periphery disposed on the frame. Two external rigid plates each having a suitable support for a membrane on its internal face clamp the frame and membrane between themselves. Appropriate structure is provided for keeping the two rigid plates fixed to one another and thereby maintaining the spatial relationship of the frame, membranes and plates.
    Type: Grant
    Filed: May 23, 1983
    Date of Patent: October 27, 1987
    Assignee: Rhone-Poulenc Specialites Chimiques
    Inventors: Michel Cronenberger, Paul Lateltin, Robert Rustant
  • Process for preparing trifluoroacetic or trichloroacetic acid esters
    Patent number: 4701551
    Abstract: A process for preparing trifluoroacetic or trichloroacetic acid esters, wherein trifluoroacetic or trichloroacetic acid is brought together with a non-perfluorinated alcohol in liquid hydrofluoric acid and wherein the ester obtained is separated by decantation. The trifluoroacetic or trichloroacetic acid esters are used as synthesis intermediates in the pharmaceutical or the plant-protection industry.
    Type: Grant
    Filed: July 21, 1986
    Date of Patent: October 20, 1987
    Assignee: Rhone-Poulenc Specialites Chimiques
    Inventors: Michel DesBois, Louis Amiet
  • Platinum/alkenylcyclohexene complexes useful for hydrosilylation catalysis
    Patent number: 4699813
    Abstract: Novel platinum/olefin complexes, useful for the hydrosilylation curing catalysis of hardenable organopolysiloxane compositions, are facilely prepared by reacting a platinum halide with at least one alkali or alkaline earth metal carbonate or bicarbonate in the presence of an alkenylcyclohexene ligand having the general formula: ##STR1## wherein R.sub.1 is an alkenyl radical having from 2 to 6 carbon atoms, and R.sub.2 is a hydrogen atom or an inert organic radical, and said complex having a ratio, in gram-atoms of halogen to gram-atoms of platinum, ranging from virtually 0 to 4.
    Type: Grant
    Filed: December 20, 1985
    Date of Patent: October 13, 1987
    Assignee: Rhone-Poulenc Specialites Chimiques
    Inventor: Jacques Cavezzan
  • Catalytic partial cyclotrimerization of polyisocyanates and product thereof
    Patent number: 4697014
    Abstract: Storage-stable polyisocyanurate-polyisocyanates, essentially devoid of polyisocyanate monomer and dimer over time, are conveniently prepared by catalytically cyclotrimerizing an aliphatic, cycloaliphatic or aromatic polyisocyanate in the presence of a catalytically effective amount of an aminosilyl catalyst, and terminating the cyclotrimerization reaction when predetermined desired amount of isocyanurate group has been reached, by adding to the reaction mixture a reaction terminating amount of water.
    Type: Grant
    Filed: March 25, 1986
    Date of Patent: September 29, 1987
    Assignee: Rhone-Poulenc Specialites Chimiques
    Inventor: Jean Robin
  • Process for preparing compounds containing a difluoromethylene group in a position .alpha. to an oxygen atom
    Patent number: 4695657
    Abstract: A process for the preparation of compounds containing a difluoromethylene group in a position .alpha. to an oxygen atom. An alcohol or a phenol is brought into contact with trifluoroacetic acid or a halide or anhydride thereof in anhydrous liquid hydrofluoric acid, in the presence of boron trifluoride, in a quantity such that the absolute pressure of boron trifluoride is at least about one bar. The compounds obtained according to the invention are used as synthesis intermediates in the pharmaceutical, plant-protection, and dye industries, as anesthetics and as additives for lubricating oils.
    Type: Grant
    Filed: December 17, 1985
    Date of Patent: September 22, 1987
    Assignee: Rhone-Poulenc Specialites Chimiques
    Inventor: Michel Desbois
  • Process for the treatment of polyorganosilazanes and/or of polyorgano(disilyl)silazanes by means of a treatment of polyorganosilazanes with a catalyst system comprising an ionic inorganic salt and a complexing compound
    Patent number: 4694060
    Abstract: A process for the treatment of polyorganosilazanes and/or polyorgano(disilyl)silazanes with an effective quantity of a catalyst system comprising (i) an ionic inorganic salt of the formula M.sup.30 A.sup.-, and (II) a compound capable of complexing with the cation M.sup.+ of the salt. The M.sup.+ cation is a metal ion or a quaternary ammonium ion, and A.sup.- is a compatible anion.The polysilazanes are selected from organopolysilazanes and organopoly(disilyl)silazanes. When treated in this manner, the polysilazanes are characterized by good thermal behavior and can, in particular, be used, after pyrolysis, as precursors of ceramic products.
    Type: Grant
    Filed: May 6, 1986
    Date of Patent: September 15, 1987
    Assignee: Rhone-Poulenc Specialites Chimiques
    Inventors: Huques Porte, Jean-Jacques Lebrun
  • Heat-curable organopolysiloxane compositions
    Patent number: 4690967
    Abstract: Improved heat-curable organopolysiloxane compositions, easily vulcanizable into silicone elastomers, are comprised of (A) a major amount of a diorganopolysiloxane gum, (B) a reinforcing filler therefor, (C) optionally, a diorganopolysiloxane oil, (D) an organic peroxide catalyst, and minor amounts of at least three of the following four additives: (E) an organohydrogenopolysiloxane, (F) an organofluorinated polymer, (G) an organosilonxane irgabcompound bearing at least one acroyloxyalkyl or methacroyloxyalkyl substituent covalently bonded to a silicon atom thereof, and (H) a boron compound.
    Type: Grant
    Filed: December 21, 1984
    Date of Patent: September 1, 1987
    Assignee: Rhone-Poulenc Specialites Chimiques
    Inventors: Robert LaGarde, Noel Bouverot
  • Polysilazane composition which can crosslink in the presence of a metal compound catalyzing a hydrosilylation reaction
    Patent number: 4689252
    Abstract: A crosslinkable composition comprising at least one polysilazane containing at least 2, preferably at least 3, .tbd.SiH groups per molecule and at least 2 SiR.sub.2 groups per molecule, R.sub.2 being an unsaturated hydrocarbon radical and a catalytically effective quantity of a metal element or of a metal compound to catalyze the hydrosilylation reaction SiH/SiR.sub.2.The compositions according to the invention can crosslink under the effect of heat and can be used for coating or impregnating substrates with ceramic material after pyrolysis. The mechanical properties of the crosslinked compositions are assessed by evaluating the relative rigidity RR measured by the fiber torsion pendulum method (FIG. 1).
    Type: Grant
    Filed: March 28, 1986
    Date of Patent: August 25, 1987
    Assignee: Rhone-Poulenc Specialites Chimiques
    Inventors: Jean-Jacques Lebrun, Huques Porte
  • Process for the preparation of organopolysilazanes and of organopoly(disilyl)silazanes with improved thermal behavior and use of such silazanes as ceramic precursors
    Patent number: 4689382
    Abstract: The present invention relates to a process for the treatment of polysilazane in a homogeneous phase with a catalytically effective quantity of an acid catalyst selected from HClO.sub.4 and CF.sub.3 SO.sub.3 H. The polysilazane is preferably selected from the group consisting of organopolysilazane, organopoly(disilyl)silazane and mixtures thereof. The organic radicals bonded to the silicon atoms are preferably saturated or aromatic hydrocarbon radicals and the silicon atoms of the polysilazane are substantially free from any hydrogen atom bonded directly to the silicon atoms.The polysilazanes treated in this manner have good thermal behavior and, are particularly useful as precursors of ceramic products.
    Type: Grant
    Filed: February 24, 1986
    Date of Patent: August 25, 1987
    Assignee: Rhone-Poulenc Specialites Chimiques
    Inventors: Jean-Jacques Lebrun, Hugues Porte
  • Platinum/triene complexes useful for hydrosilylation catalysis
    Patent number: 4687870
    Abstract: Novel platinum/olefin complexes, useful for the hydrosilylation curing catalysis of hardenable organopolysiloxane compositions, are facilely prepared by reacting a platinum halide with at least one alkali or alkaline earth metal carbonate or bicarbonate in the presence of an aliphatic triene ligand having the general formula: ##STR1## wherein R.sub.1 is a linear or branched chain alkyl radical having from 1 to 6 carbon atoms, and R.sub.2 is R.sub.1 or a linear or branched chain alkenyl radical having from 2 to 16 carbon atoms and at least one site of ethylenic unsaturation, and said complex having a ratio, in gram-atoms of halogen to gram-atoms of platinum, ranging from virtually 0 to 4.
    Type: Grant
    Filed: December 20, 1985
    Date of Patent: August 18, 1987
    Assignee: Rhone-Poulenc Specialites Chimiques
    Inventor: Jacques Cavezzan
  • Selective production of dimethyldichlorosilane
    Patent number: 4684741
    Abstract: Dimethyldichlorosilane is selectively and efficiently prepared by reacting methyl chloride with a solid contact mass comprising silicon and a catalytically effective amount of copper or a copper compound, said copper catalyst comprising (i) from about 10 to 1000 ppm of tin, antimony, or admixture thereof, or of a tin or antimony compound, or admixture thereof, (ii) from about 0.01 to 2% by weight of at least one of the metallic additives beryllium, calcium and magnesium, or compound thereof, and, optionally, (iii) from about 0.01 to 3% by weight of zinc or a zinc compound.
    Type: Grant
    Filed: February 24, 1986
    Date of Patent: August 4, 1987
    Assignee: Rhone-Poulenc Specialites Chimiques
    Inventor: Christian Prud'Homme
  • Selective preparation of monohalohydroquinones
    Patent number: 4683346
    Abstract: Hydroquinone is selectively nascently chlorinated to monochlorohydroquinone, by reacting same with an aqueous solution of hydrochloric acid and hydrogen peroxide, in the presence of an organic solvent for, and inert to, said hydroquinone.
    Type: Grant
    Filed: December 19, 1985
    Date of Patent: July 28, 1987
    Assignee: Rhone-Poulenc Specialites Chimiques
    Inventor: Serge Ratton
  • Electrolytic separation of cerium/rare earth values
    Patent number: 4676957
    Abstract: Cerium and rare earth values are separated from an aqueous medium comprised thereof, by (i) anodically electrolytically treating such aqueous medium and oxidizing the Ce (III) values therein to Ce (IV) values, (ii) extracting said electrolyzed aqueous medium with a selective organic extractant for said Ce (IV) values, and permitting the extracted medium to separate into an organic phase enriched in Ce (IV) values and a product aqueous phase enriched in rare earth values, (iii) reducing the Ce (IV) values in said organic phase to Ce (III) values and admixing same with an aqueous medium, and (iv) permitting said admixture to separate into an organic phase and a product aqueous phase enriched in Ce (III) values.
    Type: Grant
    Filed: March 25, 1986
    Date of Patent: June 30, 1987
    Assignee: Rhone-Poulenc Specialites Chimiques
    Inventors: Michel Martin, Alain Rollat