Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B82—NANOTECHNOLOGY
  • B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
  • B82Y30/00—Nanotechnology for materials or surface science, e.g. nanocomposites
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
  • C01B13/00—Oxygen; Ozone; Oxides or hydroxides in general
  • C01B13/14—Methods for preparing oxides or hydroxides in general
  • C01B13/32—Methods for preparing oxides or hydroxides in general by oxidation or hydrolysis of elements or compounds in the liquid or solid state or in non-aqueous solution, e.g. sol-gel process
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
  • C01G25/00—Compounds of zirconium
  • C01G25/02—Oxides
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
  • C01P2004/00—Particle morphology
  • C01P2004/01—Particle morphology depicted by an image
  • C01P2004/03—Particle morphology depicted by an image obtained by SEM
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
  • C01P2004/00—Particle morphology
  • C01P2004/30—Particle morphology extending in three dimensions
  • C01P2004/32—Spheres
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
  • C01P2004/00—Particle morphology
  • C01P2004/60—Particles characterised by their size
  • C01P2004/61—Micrometer sized, i.e. from 1-100 micrometer
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
  • C01P2004/00—Particle morphology
  • C01P2004/60—Particles characterised by their size
  • C01P2004/62—Submicrometer sized, i.e. from 0.1-1 micrometer
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
  • C01P2004/00—Particle morphology
  • C01P2004/60—Particles characterised by their size
  • C01P2004/64—Nanometer sized, i.e. from 1-100 nanometer

Definitions

• the subject of the invention is a process for the manufacture of metal oxide powders.
• It relates more particularly to a process for manufacturing a powder comprising at least one metal oxide, starting from a chlorinated metal compound.
• a metal chloride is reacted with an alcohol and ammonia to form a metal alcoholate and ammonium chloride, the precipitated ammonium chloride is separated, and the metal alcoholate is then treated with water to hydrolyze the alcoholate and precipitate the metal oxide (Journal of The American Ceramic Society, Vol. 48, No. 7, MAZDIYASNI ET AL "Preparation of Ultra- High-Purity Submicron Refractory Oxides ", pages 372 to 375).
• This known process involves filtration to separate the precipitate of ammonium chloride from the organic solution containing the metal alcoholate.
• Filtration is a drawback of this known process: on the one hand, it lengthens the total duration of the process; on the other hand, it is powerless to avoid the presence of ammonium chloride in the solution of the metal alcoholate.
• the presence of ammonium chloride in the organic metal alcoholate solution constitutes a disadvantage, because this compound will exert an unfavorable action on the subsequent hydrolysis step and will also contaminate the metal oxide powder.
• the invention overcomes this drawback of the known process, by providing a new process which makes it possible to obtain a metal oxide powder of high purity, starting from a chlorinated metallic compound, this process not requiring an intermediate filtration step. .
• the invention therefore relates to a method for manufacturing a powder comprising at least one metal oxide, in which an anhydrous chlorinated metal compound is reacted with an alcohol and the resulting metal alcoholate is treated with water to hydrolyze the alcoholate and precipitate the metal oxide ; according to the invention, the anhydrous chlorinated metal compound is dissolved in alcohol to which an epoxide is added, water is then added to the resulting reaction medium, and the metal oxide which precipitates is collected.
• chlorinated metal compound is intended to denote a compound in which at least one metal is associated with at least one chloride cation. This definition therefore includes not only the metal chlorides as such containing only metal anions and chloride cations, but also the chlorinated metal compounds further comprising, in the molecule, other cations and / or hydrocarbon groups. Examples of chlorinated metallic compounds falling within the scope of the invention are metallic chlorides as such and metallic chloroalkoxides.
• the chlorinated metal compound which is reacted with the alcohol must be anhydrous.
• alcohol must be taken in a very general acceptance and include linear, cyclic, saturated, unsaturated, unsubstituted and fully or partially substituted aliphatic alcohols, as well as unsubstituted or at least partially substituted phenols.
• Preferred alcohols are those whose pKa is at least equal to 16, particularly the unsubstituted saturated aliphatic alcohols such as, for example, ethanol, n-propanol, isopropanol, n-butanol and isobutanol.
• the anhydrous chlorinated metal compound is dissolved in alcohol, in the presence of an epoxide.
• the epoxide can invariably be mixed with alcohol, the anhydrous chlorinated metal compound, or the solution of this compound in alcohol.
• the chlorinated metal compound is converted to the metal alcoholate and the released hydrogen chloride is taken up by the epoxide to form the hydrochloride of the corresponding glycol, for example according to the following general reaction in the case of a metal chloride as is:
• - R denotes a hydrocarbon group in accordance with the definition given above of the term "alcohol”; - R ⁇ , R 2 , R3, R4 each denote a hydrogen atom or a saturated or unsaturated hydrocarbon group, optionally partially or totally substituted.
• the alcohol, the anhydrous chlorinated metal compound and the epoxide must therefore be used in respective amounts at least sufficient to carry out a conversion of all of the chlorinated metal compound into the alcoholate corresponding to the alcohol used.
• epoxide is dictated by the need for the metal alcoholate to be completely dissolved at the end of the reaction in the hydrochloride of the glycol produced or in the solution thereof with the alcohol when an excess of alcohol is used.
• the choice of epoxide will therefore depend on the operating conditions, in particular the pressure and the temperature, as well as the anhydrous chlorinated metal compound and the alcohol used and the respective quantities reacted. In practice, it is preferred to work in the vicinity of room temperature (generally between 15 and 25 ° C) and normal atmospheric pressure, with aliphatic epoxides, substituted or unsubstituted. Unsubstituted aliphatic epoxides are preferred and, among these, epoxypropane is especially advantageous.
• the organic solution of the alcoholate produced is collected and water is added to it to hydrolyze the alcoholate.
• the hydrolysis can be carried out in ambient air.
• a gaseous atmosphere free of moisture dry, dehydrated air, nitrogen and argon are examples of atmospheres which can be used in the process according to the invention.
• temperature and pressure are not critical. In general, in most cases, you can work at room temperature and normal atmospheric pressure.
• the hydrolysis is adjusted to precipitate the hydrated metal oxide in the form of a powder, without forming a gel.
• the water is used in the form of an organic solution.
• Alcohols and their derivatives are well suited, in particular methanol, ethanol, n-propanol, isopropanol, n-butanol and isobutanol.
• the optimum dilution rate of water in its organic solvent depends on various factors, in particular the metal alcoholate, the working temperature and the quality sought for the amorphous powder; they must be determined in each particular case by routine laboratory work. As a general rule, it is recommended that the organic water solution contains less 5 moles of water per liter. Especially advantageous molar concentrations are those between 0.1 and 3. It is also especially advantageous to carry out the hydrolysis in the presence of an acidic organic compound containing more than six carbon atoms in its molecule, as explained so detailed in Belgian patent applications 08700311 and French 8709116 (S0LVAY & Cie). To operate the mixture of water, the organic solution of the alcoholate and, where appropriate, of the acidic organic compound, it is possible to operate in the manner described in patent application GB-A-2168334.
• a powder of fine particles consisting of a complex mixture of hydrated metal oxide, in the amorphous state, and organic residues is collected.
• the powder is formed, essentially, of generally spherical particles, having a diameter not exceeding 5 microns, usually between 0.05 and 2 microns.
• the organic residues present in the amorphous powder include the hydrochlorine formed, optionally residues of the epoxide and the alcohols used and, where appropriate, the organic solvents and the acidic organic compound used in the hydrolysis step. . These residues are present in the powder in very variable amounts, depending on the conditions of the hydrolysis. Their weight content in the powder may exceed 50%, even 60%, but it is more generally between 10 and 40%.
• the powder collected after hydrolysis is advantageously subjected to drying to remove water and organic residues.
• the drying can be followed by an appropriate heat treatment to crystallize the metal oxide. If necessary, one can operate in the manner described in the Belgian patent application 08800674 (S0LVAY & Cie).
• the chlorinated metal compound which is reacted with the alcohol be anhydrous.
• this must therefore be dried or dehydrated before being treated with alcohol.
• the anhydrous chlorinated metallic compound used comes from a hydrated chlorinated metallic compound which is beforehand subjected to the following treatment: first dissolving the hydrated chlorinated metallic compound in an organic solvent having a pKa lower than 15.74 and having a boiling temperature higher than that of water or forming with water an azeotrope at least, then the resulting solution is treated to successively distill the water or the azeotrope and evaporate the solvent organic.
• the organic solvent of the hydrated chlorinated metal compound is advantageously chosen from alcohols whose pKa does not exceed 15.25 and is preferably between 12 and 15. Notwithstanding the conditions above, all alcohols may be suitable for dissolving the hydrated chlorinated metal compound.
• alcohol should be given a very general acceptance and should include phenols (unsubstituted and partially or totally substituted), as well as linear, cyclic, saturated, unsaturated aliphatic alcohols, unsubstituted and partially or totally substituted. Aliphatic alcohols are especially recommended, such as, for example, trifluoroethanols.
• Advantageous alcohols in the context of this embodiment of the invention, are those of general formula:
• Alkoxy alcohols are especially recommended, such as, for example, methoxyethanols.
• This embodiment of the method according to the invention applies in particular to hydrated metal oxychlorides.
• the process according to the invention applies to the production of powders of all metals starting from chlorinated compounds thereof. It applies equally to the production of isolated metal oxide powders or mixed metal oxide powders. It is specially adapted for the production of metal oxide powders, intended for the processing of materials ceramics which, by definition, are non-metallic inorganic materials, the implementation of which starting from a powder requires treatments at high temperature, such as melting or sintering treatments (P.
• inventions particularly finds an interesting application for the manufacture of metal oxide powders belonging to groups 2, 3 and 4 of the periodic table of the elements, possibly associated with oxides of elements belonging to the group of rare earths, in particular crystals of zirconium oxide alone or in combination with substances capable of stabilizing its tetragonal allotropic form or its cubic allotropic form at low temperatures (especially at room temperature).
• the invention therefore also relates to metal oxide powders obtained by the process according to the invention. It especially relates to zirconium oxide powders obtained by said process, which are formed of spherical grains whose diameter is between 0.05 and 2 microns.
• the invention is explained below, in a particular embodiment applied to the manufacture of a zirconium oxide powder, with reference to the single figure of the attached drawing, which is a photographic reproduction of a powder of zirconium oxide according to the invention, at 20,000 X magnification.
• the abovementioned organic solution of zirconium propanolate being maintained in the enclosure under an atmosphere of anhydrous nitrogen at 25 ° C., it was subjected to intense stirring and the propanolic solution of water and water was added thereto at once. oleic acid. The agitation was adjusted so as to obtain a homogeneous reaction mixture before nucleation of zirconium oxide began.
• the reaction mixture was then subjected to maturing for approximately 2 hours, with moderate stirring. After ripening, the reaction mixture was subjected to centrifugation and a powder was collected which was washed with anhydrous alcohol, then dried using a stream of anhydrous air, at room temperature.
• the figure shows a sample of the powder collected after drying. This has been found to consist of substantially spherical particles of amorphous hydrated zirconium oxide, with an average diameter of 0.5 microns.

Landscapes

• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Engineering & Computer Science (AREA)
• Inorganic Chemistry (AREA)
• Nanotechnology (AREA)
• Composite Materials (AREA)
• Materials Engineering (AREA)
• Crystallography & Structural Chemistry (AREA)
• General Physics & Mathematics (AREA)
• Condensed Matter Physics & Semiconductors (AREA)
• Physics & Mathematics (AREA)
• Inorganic Compounds Of Heavy Metals (AREA)
• Oxygen, Ozone, And Oxides In General (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=9372131

Family Applications (2)

Family Applications After (1)

Country Status (9)

Families Citing this family (2)

Family Cites Families (2)

• 1988
  • 1988-11-18 FR FR8815228A patent/FR2639341B1/fr not_active Expired - Fee Related
• 1989
  • 1989-10-31 CA CA002001848A patent/CA2001848A1/fr not_active Abandoned
  • 1989-11-10 KR KR1019900701432A patent/KR900701651A/ko not_active Withdrawn
  • 1989-11-10 WO PCT/BE1989/000048 patent/WO1990005699A1/fr not_active Ceased
  • 1989-11-10 DE DE8989870178T patent/DE68906128T2/de not_active Expired - Fee Related
  • 1989-11-10 EP EP89912215A patent/EP0444060A1/fr active Pending
  • 1989-11-10 JP JP1511339A patent/JPH04501702A/ja active Pending
  • 1989-11-10 AT AT89870178T patent/ATE88441T1/de not_active IP Right Cessation
  • 1989-11-10 EP EP89870178A patent/EP0369979B1/fr not_active Expired - Lifetime
• 1991
  • 1991-05-17 DK DK093991A patent/DK93991A/da not_active Application Discontinuation

Non-Patent Citations (1)

Also Published As

Similar Documents

Legal Events