Classifications

• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01F—COMPOUNDS OF THE METALS BERYLLIUM, MAGNESIUM, ALUMINIUM, CALCIUM, STRONTIUM, BARIUM, RADIUM, THORIUM, OR OF THE RARE-EARTH METALS
  • C01F7/00—Compounds of aluminium
  • C01F7/02—Aluminium oxide; Aluminium hydroxide; Aluminates
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
  • B01J23/005—Spinels
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
  • B01J23/06—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of zinc, cadmium or mercury
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
  • B01J23/70—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper
  • B01J23/72—Copper
• • 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
  • C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
  • C01G3/00—Compounds of copper
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
  • C01G45/00—Compounds of manganese
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
  • C01G49/00—Compounds of iron
  • C01G49/0018—Mixed oxides or hydroxides
  • C01G49/0045—Mixed oxides or hydroxides containing aluminium
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
  • C01G51/00—Compounds of cobalt
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
  • C01G53/00—Compounds of nickel
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
  • C01G9/00—Compounds of zinc
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09C—TREATMENT OF INORGANIC MATERIALS, OTHER THAN FIBROUS FILLERS, TO ENHANCE THEIR PIGMENTING OR FILLING PROPERTIES ; PREPARATION OF CARBON BLACK  ; PREPARATION OF INORGANIC MATERIALS WHICH ARE NO SINGLE CHEMICAL COMPOUNDS AND WHICH ARE MAINLY USED AS PIGMENTS OR FILLERS
  • C09C1/00—Treatment of specific inorganic materials other than fibrous fillers; Preparation of carbon black
  • C09C1/0009—Pigments for ceramics
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
  • C01P2002/00—Crystal-structural characteristics
  • C01P2002/30—Three-dimensional structures
  • C01P2002/32—Three-dimensional structures spinel-type (AB2O4)
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
  • C01P2004/00—Particle morphology
  • C01P2004/50—Agglomerated particles
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
  • C01P2004/00—Particle morphology
  • C01P2004/51—Particles with a specific particle size distribution
• • 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
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
  • C01P2006/00—Physical properties of inorganic compounds
  • C01P2006/60—Optical properties, e.g. expressed in CIELAB-values

Definitions

• the present invention relates to the production of nanoparticles consisting of aluminum spinels and their use
• Aluminum spinels occur naturally as mineral substances, their production in nanocrystalline form as well as their use in a variety of applications
• Zinc spinel also has a bandgap and therefore exhibits interesting optical properties that make the material suitable for electroluminescent applications (Hiroaki Matsui, Chao-Nan Xu, Yun Liu, Hiroshi Tateyama, Physical Review B 69, 235109 (2004), as required in LEDs and Display, to qualify.
• the aim of the present invention is therefore to provide a process for the production of nano-crystalline aluminum spinels, which provides high yields in a short time with minimal energy input.
• the resulting product should be redispersible by simple means and thus be able to deliver stable nano-suspensions.
• This object has been achieved by the method described below, the special feature of which is that a calcination of less than 30 minutes is sufficient here.
• the invention relates to a process for the production of nanoparticles from aluminum spinels, wherein an aqueous solution of aluminum chlorohydrate with a salt of a metal whose oxide can form a spinel lattice with alumina, then dried, calcined within less than 30 minutes and the resulting Crushed agglomerates.
• the starting point for the process according to the invention is aluminum chlorohydrate, which has the formula Al 2 (OH) x Cl y, where x is a number from 2.5 to 5.5 and y is a number from 3.5 to 0.5 and the sum of x and y is always 6. Preference is given to starting from 50% aqueous solutions of aluminum chlorohydrate, as they are commercially available.
• Suitable metal salts of this type are all divalent metal salts, for example the divalent salts of cobalt, zinc, manganese, copper, iron, magnesium, cadmium, nickel.
• Spinels have the molecular formula MaI 2 O 4 , where M represents the divalent metal. From this empirical formula automatically results in the amount of metal salt, which are added according to the invention to the solution of Aluminiumchlorohydrats got to. Since the spinel lattice can also contain defects, it is also possible to deviate from the stoichiometrically calculated value in the amount of metal M or the amount of metal salt, based on the A 2 O 6 matrix. In general, the amount of metal salt based on the Al 2 O 3 matrix is 30 to 80, preferably 50 mol%.
• this solution is also mixed with seed nuclei, which promote the formation of the spinel lattice.
• seed nuclei which promote the formation of the spinel lattice.
• such nuclei cause a lowering of the temperature for the formation of the spinel lattice in the subsequent thermal treatment.
• Suitable nuclei are very finely dispersed spinels, for example zinc spinel, having an average particle size of less than 0.1 .mu.m. In general, 2 to 3 wt .-% of germs, based on the resulting spinel rich.
• This suspension of aluminum chlorohydrate and metal salt, and optionally nuclei is then allowed to dry, e.g. by spray drying, freeze-drying, granulation or by roller dryer and subjected to a thermal treatment (calcination).
• This calcination takes place in suitable devices, for example in push-through, chamber, tube or microwave ovens or in a
• Fluidized bed reactor Particularly suitable rotary kilns, which allow a high throughput with low residence time.
• the temperature for the calcination should not exceed 1100 0 C.
• the lower temperature limit depends on the desired yield of aluminum spinel and the desired residual chlorine content.
• the spinel is depending spinel starting at about 400 0 C., but to keep the chlorine content low and the yield of spinel high, will be applied, however, slightly higher temperatures.
• Is for zinc spinel as the preferred temperature is about 850 0 C.
• the time for calcination is generally less than 30 minutes and may be only a few minutes, depending on the type of spinel.
• agglomerates of the aluminum spinel accumulate in the form of nearly spherical primary crystallites, the term "nano-" being understood to mean a particle size of generally from 1 to 100 nm.
• These agglomerates are deagglomerated in a subsequent step using any of the deagglomeration techniques known in the art, such as milling or feeding ultrasonic energy, since in the present case, they are relatively easily destructible soft agglomerates.
• the deagglomeration is preferably carried out at temperatures of 20 to 100 0 C, more preferably at 20 to 90 0 C.
• the wet grinding preferably takes place in an attritor or agitator ball mill, while dry grinding in an air jet mill is carried out. Since the nanoparticles aimed at as a product during grinding are extremely reactive, it is preferred to add additives before or during the grinding which prevent re-agglomeration of the nanoparticles. It is therefore particularly favorable to carry out the subsequent deagglomeration in the form of a wet grinding.
• vibration mills, attritor mills, ball mills, stirred ball mills or similar devices are suitable. The use of agitator ball mills has proven to be particularly advantageous.
• the grinding time depends on the strength of the agglomerates and the desired fineness and is usually between 2 and 6 hours in the process according to the invention.
• Wet grinding or deagglomeration is advantageously carried out in an aqueous medium, but it is also possible to use alcoholic or other organic solvents.
• alcoholic or other organic solvents For example, after a six-hour grinding in water, an aqueous suspension of nanocrystalline aluminum spinel having a d90 value of about 30 nm is obtained.
• the suspension obtained after wet grinding can be converted into a defined powder by spray drying, fluidized bed drying, granulation or freeze drying. Another possibility is to modify the surfaces of the nanospinels and thus to obtain an adaptation to organic solvents and coating materials.
• nanoparticles For the inventive modification of the surface of these nanoparticles with coating agents such.
• coating agents such as silanes or siloxanes there are two possibilities.
• deagglomeration can be carried out in the presence of the coating agent, for example by adding the coating agent to the mill during milling.
• a second possibility consists of first destroying the agglomerates of the nanoparticles and then treating the nanoparticles, preferably in the form of a suspension in a solvent, with the coating agent.
• Suitable solvents for deagglomeration are both water and customary solvents, preferably those which are also used in the coatings industry, such as, for example, C 1 -C 4 -alcohols, in particular methanol, ethanol or isopropanol, acetone , Tetrahydrofuran, butyl acetate.
• an inorganic or organic acid such as HCl, HNO 3 , formic acid or acetic acid should be added to stabilize the resulting nanoparticles in the aqueous suspension.
• the amount of acid may be 0.1 to 5 wt .-%, based on the mixed oxide.
• aqueous suspension of the acid-modified nanoparticles is then preferably the grain fraction having a particle diameter of less than 20 nm separated by centrifugation.
• the coating agent preferably a silane or siloxane
• the nanoparticles thus treated precipitate are separated and dried to a powder, for example by freeze-drying.
• Suitable coating agents are preferably silanes or siloxanes or mixtures thereof.
• suitable coating agents are all substances which can bind physically to the surface of the mixed oxides (adsorption) or which can bond to form a chemical bond on the surface of the mixed oxide particles. Since the surface of the mixed oxide particles is hydrophilic and free hydroxy groups are available, suitable coating agents are alcohols, compounds having amino, hydroxyl, carbonyl, carboxyl or mercapto functions, silanes or siloxanes. Examples of such coating compositions are polyvinyl alcohol, mono-, di- and tricarboxylic acids, amino acids, amines, waxes, surfactants, hydroxycarboxylic acids, organosilanes and organosiloxanes.
• Suitable silanes or siloxanes are compounds of the formulas
• n is an integer meaning 1 ⁇ n ⁇ 1000, preferably 1 ⁇ n ⁇ 100
• m is an integer 0 ⁇ m ⁇ 12
• p is an integer 0 ⁇ p ⁇ 60
• q is an integer 0 ⁇ q ⁇ 40
• r is an integer 2 ⁇ r ⁇ 10 and s is an integer 0 ⁇ s ⁇ 18 and
• Y is a reactive group, for example ⁇ , ß-ethylenically unsaturated groups, such as (meth) acryloyl, vinyl or allyl groups, amino, amido , Ureido, hydroxyl, epoxy, isocyanato, mercapto, sulfonyl, phosphonyl, trialkoxylsilyl, alkyldialkoxysilyl, dialkylmonoalkoxysilyl, anhydride, and / or carboxyl groups, imido, imino, sulfite, sulfate,
• X is a t-functional oligomer with t an integer 2 ⁇ t ⁇ 8 and Z in turn a residue
• the t-functional oligomer X is preferably a:
• radicals of oligoethem are compounds of the type - (CaH2a-O) b-CaH2a- or O- (CaH2a-O) b-CaH2a-O with 2 ⁇ a ⁇ 12 and 1 ⁇ b ⁇ 60, z.
• Diethylengiykol- triethylene glycol or tetraethylene glycol radical, a dipropylene glycol, Tripropylenglykol-, tetrapropylene glycol radical, a dibutylene glycol, tributylene glycol or tetrabutylene glycol radical.
• residues of oligoesters are compounds of the type -CbH2b- (C (CO) CaH2a- (CO) O-CbH2b-) c- and -O-CbH2b- (C (CO) CaH2a- (CO) O-)
• C CH2 -OCH2-CH (O) CH2
• silanes of the type defined above are, for. Hexamethyldisiloxane, octamethyltrisiloxane, other homologous and isomeric compounds of the series SinOn-1 (CH 3) 2n + 2, where n is an integer 2 ⁇ n ⁇ 1000, e.g. B. Polydimethylsiloxane 200® fluid (20 cSt).
• Dihydrohexamethytrisiloxane, dihydrooctamethyltetrasiloxane other homologous and isomeric compounds of the series H - [(Si-O) n (CH 3) 2n] -Si (CH 3) 2 -H, where n is an integer 2 ⁇ n ⁇ 1000, preferably the ⁇ . ⁇ -dihydropolysiloxanes, e.g. B. polydimethylsiloxane (hydride end groups, Mn 580).
• ⁇ -OH groups are also the corresponding difunctional compounds with epoxy, isocyanato, vinyl, AIIyI- and di (meth) acryloyl used, for.
• R 1 is an alkyl, such as. Methyl, ethyl, n-propyl, i-propyl, butyl,
• R 1 is a cycloalkyl n is an integer from 1 to 20 x + y 3 x 1 or 2 y 1 or 2
• R 1 is methyl, phenyl, -C 4 F 9; OCF2-CHF-CF3, -C6F13, -O-CF2-CHF2, -NH2, -N3,
• R " 1 " H, alkyl
• Preferred silanes are the silanes listed below: triethoxysilane, octadecyltimethoxysilane, 3- (trimethoxysilyl) -propylmethacrylate, 3- (trimethoxysilyl) -propylacrylate, 3- (trimethoxysilyl) -methylmethacrylate, 3- (trimethoxysilyl) -methylacrylate, 3- (trimethoxysilyl) ethyl methacrylates, 3- (trimethoxysilyl) ethyl acrylates, 3- (trimethoxysilyl) pentyl methacrylates, 3- (trimethoxysilyl) pentyl acrylates, 3- (trimethoxysilyl) pentyl acrylates, 3- (trimethoxysilyl) -hexylmethacrylate, 3- (trimethoxysilyl) -hexylacrylate, 3- (trimethoxysilyl)
• the coating compositions are preferably added in molar ratios of aluminum spinel nanoparticles to silane of from 1: 1 to 10: 1.
• the amount of solvent in the deagglomeration is generally 50 to 90 wt .-%, based on the total amount of aluminum spinel nanoparticles and solvent.
• the deagglomeration by grinding and simultaneous modification with the coating agent is preferably carried out at temperatures of 20 to 150 0 C, more preferably at 20 to 90 0 C.
• the suspension is subsequently separated from the grinding beads. After deagglomeration, the suspension can be heated to complete the reaction for up to 30 hours. Finally, the solvent is distilled off and the remaining residue is dried. It may also be advantageous to leave the modified aluminum spinel nanoparticles in the solvent and to use the dispersion for other applications.
• the aluminum spinels produced according to the invention can be used very widely as described at the beginning.
• the zinc spinel is suitable because of its band gap as a UV absorber in coatings.
• the zinc spinel has the advantage of UV absorption while increasing the scratch and abrasion resistance, due to the Mohs hardness of 8.
• the nanostructured material can be used as a catalyst material or as a semiconducting material for light-emitting diodes and displays.
• Cobalt spinel has already been described as a high temperature stable pigment. With the method according to the invention nanosuspensions can be formulated simply and efficiently. The incorporation into binder systems and formulations is possible without problems. Especially copper spinel is suitable as a catalytically active material due to the large active surface area and because of the copper ion.
• a 50% aqueous solution of aluminum chlorohydrate was added with zinc chloride such that after calcination the ratio of alumina to zinc oxide is 50:50. After the solution is homogenized by stirring was, the drying is carried out in a rotary evaporator. The solid aluminum chlorohydrate zinc chloride mixture was crushed in a mortar to form a coarse powder.
• the powder was calcined in a rotary kiln at 85 0 C.
• the contact time in the hot zone was a maximum of 5 min.
• a white powder was obtained whose grain distribution corresponded to the feed material.
• Zirconia (stabilized with yttrium) and had a size of 0.3 mm.
• the pH of the suspension was checked every 30 minutes and kept at pH 4-4.5 by the addition of dilute nitric acid. After 6 hours, the suspension was separated from the grinding beads and analyzed by means of an analytical
• Cobalt chloride was added to a 50% aqueous solution of aluminum chlorohydrate such that after calcination the ratio of alumina to cobalt oxide was 50:50. After the solution has been homogenized by stirring, the drying is carried out in a rotary evaporator. The solid aluminum chlorohydrate-cobalto-chloride mixture was crushed in a mortar to form a coarse powder. The powder was calcined in a rotary kiln at 1000 0 C. The contact time in the hot zone was a maximum of 5 min. It was obtained a deep blue powder whose grain size corresponded to the feed. An X-ray structure analysis showed that there is a spinel lattice.

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• 2006
  • 2006-07-13 DE DE102006032582A patent/DE102006032582A1/de not_active Withdrawn
• 2007
  • 2007-07-07 CN CN200780026387.6A patent/CN101489934B/zh not_active Expired - Fee Related
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