Rhone-poulenc Specialites Chimiques

Rhone-poulenc Specialties Chimiques

Rhone-poulenc Chimie

Jean-Yves Dumousseau

Jean-Yves Chane-Ching

Jean Grosbois

Jean Bachot

Serge Jacubert

Jean-Louis Sabot

Alain Rollat

Jean-Michel Verdier

Patrick Dupuis

Storage-stable sols are comprised of a colloidal dispersion of Ce (IV) values in an aqueous medium, and optionally colloidal particulates of a cation of a metal M, with said colloidal dispersion being 'supersaturated' in [OH.sup.- ] ions.

Preparing storage stable aqueous colloidal dispersions of cerium (IV)

Morphologically improved cerium oxide particulates having low sulfur content, useful, e.g., as catalyst/catalyst supports, and having a B.E.T. specific surface of at least 130 m.sup.2 /g measured at a temperature ranging from 400.degree. C. to 500.degree. C., are prepared by reacting an aqueous solution of cerium (IV) salt with an aqueous solution of sulfate ions to precipitate a basic ceric sulfate, filtering the precipitate which results, washing and optionally drying said precipitate, and thence calcining same.

Novel cerium oxide particulates

Morphologically improved cerium oxide particulates useful, e.g., as catalysts/catalyst supports, and having a B.E.T. specific surface of from 100 to 130 m.sup.2 /g, measured at a temperature ranging from 400.degree. C. to 450.degree. C., are prepared by hydrolyzing an aqueous solution of a cerium (IV) salt in an acidic medium, filtering the precipitate of hydrolysis which results, washing and optionally drying said precipitate, and thence calcining same.

Highly pure europium (II) values are produced in high yields by electrolytically reducing an aqueous solution of europium (III) values circulating in the cathode compartment of an electrolytic cell, the electrolytic cell including a graphite cathode and an anode compartment separated from the cathode compartment by a cationic exchange membrane, recovering a solution of europium (II) values from the cathode compartment, and advantageously liquid/liquid extracting the europium (II) values thereform, e.g., with an organic solution of an organophosphorus extractant.

Recovery of europium (II) values by electrolysis

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.

Production of stannous salts

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.

Electrolytic oxidation/apparatus

Morphologically improved cerium oxide particulates useful, e.g., as catalysts/catalyst supports, and having a B.E.T. specific surface of at least 85.+-.5 m.sup.2 /g, measured at a temperature ranging from 350.degree. C. to 450.degree. C., are prepared by hydrolyzing an aqueous solution of a cerium (IV) salt in an acidic medium, filtering the precipitate of hydrolysis which results, washing and optionally drying said precipitate, and then calcining same.

Process for producing cerium oxide particulates

Morphologically improved cerium oxide particulates having low sulfur content, useful, e.g., as catalysts/catalyst supports, and having a B.E.T. specific surface of at least 85.+-.5 m.sup.2 /g, measured at a temperature ranging from 350.degree. C. to 500.degree. C., are prepared by reacting an aqueous solution of cerium (IV) salt with an aqueous solution of sulfate ions to precipitate a basic ceric sulfate, filtering the precipitate which results, washing and optionally drying said precipitate, and then calcining same.

Process for the preparation of cerium oxide particulates

Electrolytic oxidation

Lithium metal is continuously prepared by, in a specially adapted electrolytic cell, (i) continuously electrolyzing the lithium chloride which comprises a mixture of molten salts, which mixture comprises the medium of electrolysis and such medium of electrolysis naturally circulating within an interspace defined between the electrodes of the cell, said interspace being devoid of physical barrier between said electrodes, (ii) continuously withdrawing therefrom product lithium metal in admixture with the mixture of molten salts, and (iii) continuously discharging undiluted chlorine gas therefrom.

Continuous electrolysis of lithium chloride into lithium metal

Lithium is continuously converted into lithium hydride, is suitable phase contactor/decanter apparatus, by continuously hydrogenating in a first reaction zone, at elevated temperatures, an agitated intimate admixture of metallic lithium in a mixture of molten salts, continuously discharging the effluent of said hydrogenation reaction to a second zone of decantation, whereby said effluent is separated into a floating light phase essentially consisting of unreacted lithium metal and a heavy phase which comprises product lithium hydride dissolved in said mixture of molten salts, continuously recycling floating light phase back to the hydrogenation reaction zone, continuously withdrawing heavy phase from said zone of decantation, and recovering product lithium hydride from said withdrawn heavy phase.

Continuous hydrogenation of lithium into lithium hydride

Silane, a useful intermediate in the production of silicon, is facilely quantitatively prepared by hydrogenating chlorosilanes in a bath of molten salts, said molten bath comprising a ternary mixture of lithium chloride and two other metal chlorides, such two other metal chlorides being either two different alkaline earth metal chlorides, or one alkaline earth metal chloride and one alkali metal chloride, or two different alkali metal chlorides, and said ternary mixture having a melting point not in excess of about 400.degree. C.

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Paris, France

Jean-Yves Dumousseau