Abstract: The present invention relates to a process for preparing mineral particles (p) from mineral species precursors, said process comprising a step (E) in which a fluid medium (F) containing said precursors in solution and/or dispersed in a solvent is injected into a reactor containing CO2 in the supercritical state by way of an injection nozzle opening into a zone where the supercritical CO2 is at a temperature greater than or equal to the temperature for conversion of the precursors into corresponding mineral species. The invention also relates to the particles (p) as obtained by the process, as well as uses thereof.

Abstract: A process for the “in situ” manufacture, in a pressurized CO2 medium, of coated particles. The manufacturing process is characterized in that the steps of synthesising the particles and of coating these particles are coupled in such a way that the synthesised particles remain dispersed in a pressurized CO2 medium at least until the coating. The device comprises a reactor for synthesising particles in a pressurized CO2 medium; a means of injecting the coating material or precursor thereof into said reactor; a means of supplying said reactor with a pressurized CO2 medium; in which the means of injecting the coating material or precursor thereof is coupled to the synthesis reactor in such a way that the injection of the coating material or precursor thereof into said reactor does not destroy the dispersion of the particles, in a pressurized CO2 medium, in said reactor.

Abstract: The subject of the present invention is a method for producing a gas separation membrane, comprising the deposition of a film from a silica sol onto a porous support followed by heat treatment of the film thus deposited, in which the silica sol deposited is prepared by hydrolysing a silicon alkoxide in the presence of a doping amount of a precursor of an oxide of a trivalent element, especially boron or aluminium. The invention also relates to the membranes as obtained by this method, and also to their uses, especially for the separation of helium or hydrogen at high temperature, and in particular for removing impurities in helium streams.

Abstract: Process for the oxidation of a hydrocarbon substrate to a corresponding oxidised hydrocarbon compound by contacting the hydrocarbon substrate with an oxygen containing atmosphere in presence of a catalyst being active in the oxidation of the hydrocarbon substrate, which process comprises the steps of: passing a process gas containing the hydrocarbon substrate through a reaction zone with the catalyst; introducing the oxygen containing atmosphere divided into a plurality of substreams successively into the reaction zone; within the reaction zone reacting the process gas continuously with the oxygen containing atmosphere; and withdrawing from the reaction zone a product gas containing oxidised hydrocarbon compound and carbon monoxide.

Abstract: This invention relates to a method of manufacturing a product based on a simple or mixed metal oxide, or silicon oxide, from a charge of one or more precursors comprising one or more organic precursors. These oxides can be, for example, oxides of Ti, Al, Mg, Th, Si, Ba, Bc or Zr etc. The method comprises bringing the charge of organo-metallic precursors into contact with a reaction medium that comprises supercritical C02, at a temperature of from 31 to 100° C. and a supercritical pressure of from 3×107 to 5×107 Pa, in order to form from the precursor, a product based on a simple or mixed metal oxide, or silicon oxide, from the reaction medium by reducing the pressure of the supercritical C02 to a pressure lower than the supercritical pressure.