Classifications

• • 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
  • B01J2/00—Processes or devices for granulating materials, e.g. fertilisers in general; Rendering particulate materials free flowing in general, e.g. making them hydrophobic
  • B01J2/02—Processes or devices for granulating materials, e.g. fertilisers in general; Rendering particulate materials free flowing in general, e.g. making them hydrophobic by dividing the liquid material into drops, e.g. by spraying, and solidifying the drops
  • B01J2/06—Processes or devices for granulating materials, e.g. fertilisers in general; Rendering particulate materials free flowing in general, e.g. making them hydrophobic by dividing the liquid material into drops, e.g. by spraying, and solidifying the drops in a liquid medium
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
  • B01F23/00—Mixing according to the phases to be mixed, e.g. dispersing or emulsifying
  • B01F23/40—Mixing liquids with liquids; Emulsifying
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
  • B01F23/00—Mixing according to the phases to be mixed, e.g. dispersing or emulsifying
  • B01F23/50—Mixing liquids with solids
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
  • B01F25/00—Flow mixers; Mixers for falling materials, e.g. solid particles
  • B01F25/40—Static mixers
  • B01F25/45—Mixers in which the materials to be mixed are pressed together through orifices or interstitial spaces, e.g. between beads
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
  • B01F25/00—Flow mixers; Mixers for falling materials, e.g. solid particles
  • B01F25/40—Static mixers
  • B01F25/45—Mixers in which the materials to be mixed are pressed together through orifices or interstitial spaces, e.g. between beads
  • B01F25/452—Mixers in which the materials to be mixed are pressed together through orifices or interstitial spaces, e.g. between beads characterised by elements provided with orifices or interstitial spaces
  • B01F25/4521—Mixers in which the materials to be mixed are pressed together through orifices or interstitial spaces, e.g. between beads characterised by elements provided with orifices or interstitial spaces the components being pressed through orifices in elements, e.g. flat plates or cylinders, which obstruct the whole diameter of the tube
• • 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
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B82—NANOTECHNOLOGY
  • B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
  • B82Y40/00—Manufacture or treatment of nanostructures
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F2/00—Processes of polymerisation
  • C08F2/12—Polymerisation in non-solvents
  • C08F2/16—Aqueous medium
  • C08F2/22—Emulsion polymerisation
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F2/00—Processes of polymerisation
  • C08F2/32—Polymerisation in water-in-oil emulsions
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F2/00—Processes of polymerisation
  • C08F2/44—Polymerisation in the presence of compounding ingredients, e.g. plasticisers, dyestuffs, fillers

Definitions

• the present invention relates to a method for producing nanoparticles and / or nanostructured particles by means of an emulsion method, wherein particles are produced by targeted coalescence of at least two mini-emulsions.
• Nanoparticles may be constructed, for example, of inorganic or polymeric material. They have in many cases an average particle size of 1 to 1000 nm.
• inorganic particles e.g. the sol-gel process and the micro-emulsion technique known.
• Polymeric nanoparticles may e.g. be prepared by emulsion polymerization. The targeted formation and structuring of nanoparticles is of particular interest in order to achieve special properties of nanoparticles for highly specialized applications.
• Emulsions are finely divided mixtures of at least two liquids which are not homogeneously miscible with one another.
• An example is the mixture of oil and water.
• a liquid forms the so-called inner or disperse phase (also disperse phase), which is distributed in the form of small droplets in the second liquid, the so-called outer or continuous phase.
• Important constituents of emulsions are surface-active substances, so-called surfactants or emulsifiers, which facilitate the formation of the droplets and counteract demixing (phase separation).
• O emulsion oil-in-water emulsions
• W / O oil-in-water emulsions
• Emulsions are most likely to remain stable for a period of time and under certain conditions (e.g., temperature, pH range).
• mini-emulsion refers to a thermodynamically unstable emulsion, wherein the disperse phase is present in very finely divided droplets with an average droplet diameter of ⁇ 10 .mu.m, in particular ⁇ 5 .mu.m.
• Mini-emulsions are obtained, for example, by shearing with a high energy input, starting from two (or more) immiscible liquids and one or more surfactants (surfactant, emulsifier).
• the droplets of a mini-emulsion can under certain conditions be kept stable for a certain period of time, so that the production of particles in mini-emulsions can take place by the fusion of different droplets.
• the required energy input (for example in a shearing process) for the production of mini-emulsions can be carried out, for example, by ultrasound treatment or by using a high-pressure homogenizer. Accordingly, mini-emulsions are described in which a solid, for example in the form of nanoparticles, is contained in the disperse phase as mini-suspoemulsions.
• micro-emulsions which are a special case and exist only in special composition ranges in the phase system water-oil emulsifier, are referred to as micro-emulsions. They form spontaneously and often appear transparent. They usually contain a high proportion of surfactant and also usually another surfactant, a co-surfactant. If two micro-emulsions mixed with different reactants in the disperse phase, it comes to a mass transfer between the disperse phases and thus to the reaction without the emulsion drops must be coalesced with energy input.
• Mini-emulsion processes for the construction of structured nanoparticles are described in the prior art.
• the publication by K. Landfester (Adv. Mater. 2001, 13, No.10, 17.05.2001) describes the preparation of mini-emulsions and the use of mini-emulsions in the synthesis of nanoparticles and encapsulated nanoparticles.
• the synthesis of nanoparticles can be carried out, for example, with the aid of miniemulg striv molten salts or via the polymerization of a miniemulg striv monomer.
• a possibility for the targeted coalescence of mini-emulsion drops is not described.
• WO 2008/058958 describes the preparation of core-shell particles, wherein an outer layer is applied to solid nanoparticles dispersed in a mini-suspoemulsion, by applying an emulsion in the dispersed (preferably aqueous) emulsion in an emulsion process with an emulsion. Phase dissolved precursor substance is converted in the disperse phase and thus applied to the dispersed nanoparticles.
• the preparation of spherical inorganic nanoparticles by precipitation in a 2-emulsion method using microemulsions is known.
• Lee et al. J. European Ceramic Society, 19, 1999
• mini-emulsions and mini-suspoemulsions can be prepared not only using a high-pressure homogenizer, but that mini-emulsions / mini-suspoemulsions or mixtures of different mini-emulsions / mini-suspoemulsions using a high-pressure homogenizer targeted to Coalescence can be performed.
• the droplets of the disperse phase of a mini-emulsion can be coalesced in a controlled manner if they are passed under high shear through (at least) one nozzle, for example a special homogenizing nozzle.
• High-pressure homogenizers were originally developed for the homogenization of milk, in which the fat droplets of the milk are reduced to a mean drop diameter of 1 to 2 microns, so as to prevent the creaming of the milk.
• High-pressure homogenizers work according to the pressure relief system and consist essentially of a high-pressure pump and a homogenizing valve. High pressure homogenizers usually work in a pressure range of 100 to 1000 bar. The liquid flow generated by the high pressure pump (for example, a high pressure piston pump) flows through the homogenizer nozzle.
• homogenizers and homogenizing nozzles are described in the prior art, such as flat nozzles, pinhole diaphragms, slit diaphragms, diverting nozzles, counter-jet dispersing agents. It is also possible to work with combinations of several identical or different homogenizing nozzles, whereby a back pressure is built up.
• a homogenizing nozzle is the so-called flat nozzle.
• the liquid flow flows through the valve seat and then radially through the homogenizing gap, which is only a few micrometers wide.
• the homogenizing gap is set by pressing a valve body onto the valve seat.
• the liquid exits the homogenizing nip at very high speed (e.g., about 300 m / s), impacts the baffle ring, and exits the valve via the outlet.
• homogenizers include e.g. Two-jet nozzles or the combination of, for example, two pinhole diaphragms and the combination of pinhole with deflecting nozzles. Through a downstream pinhole or Umlenkdüse creates a back pressure, with the help of which the cavitation results can be influenced behind the first panel.
• Cavitation refers to the formation and dissolution of cavities in liquids due to pressure fluctuations.
• the cavitation arises, for example, as a result of very fast moving objects in the liquid (for example propeller, stirrer) or by rapid movement of the liquid, for example through a nozzle, and by the action of ultrasound.
• Emulsifying pressure is the pressure drop across the homogenizing nozzle.
• nanoparticles also refers to nanoparticles which are present or are obtained in the form of a nanohuspoemulsion or nanosuspension.
• a method for the production of nanoparticles in the context of the present invention comprises methods for the construction of nanoparticles and methods for nanostructuring of particles, in particular of nanoparticles.
• Nanostructuring comprises the production of a structure whose dimensions are in the size range of nanometers, such as, for example, the production of core-shell particles or the application of nanoscale regions to a particle surface, in particular a nanoparticle surface.
• a method for producing nanoparticles in the context of the present invention comprises a method for constructing nanoparticles, in particular from molecularly disperse-dissolved precursor substances.
• the present invention relates to a process for the preparation of nanoparticles, wherein in a first step a) at least two mini-emulsions and / or mini-suspoemulsions are produced, each containing at least one reactant in the disperse phase and at least one emulsifier, and in one second step b) the mini-emulsions and / or mini-suspoemulsions thus produced are preferably mixed in a high-pressure homogenizer.
• the production of the mini-emulsions and / or mini-suspoemulsions in step a) preferably takes place in a high-pressure homogenizer under an emulsifying pressure in the range from 200 to 1000 bar, particularly preferably in the range from 200 to 800 bar, more preferably in the range from 400 to 800 bar.
• mini-emulsions which were prepared by another known method (for example by ultrasonic treatment).
• the mixing of the mini-emulsions and / or mini-suspoemulsions in step b) takes place in a high-pressure homogenizer.
• the mixing in step b) takes place in a high-pressure homogenizer under an emulsifying pressure in the range from 100 to 1000 bar, preferably in the range from 400 to 1000 bar, particularly preferably in the range from 800 to 1000 bar.
• the production of nanoparticles is carried out according to the method of the invention in particular by selectively coalescing the droplets of two mini-emulsions / mini-suspoemulsions with different disperse phases in which the reactants are present separately, the reactants being mixed and reacted.
• the droplet coalescence can be controlled in a targeted manner (for example by the design and combination of the nozzles or the nozzle geometry) according to the present invention, taking advantage of the phenomenon of the short instability of the emulsion droplets and the resulting drop coalescence after the homogenizing nozzle.
• the process steps of the 2-emulsion method for particle generation initially involve the separate preparation of two mini-emulsions and / or mini-suspoemulsions (step a)), these starting mini-emulsions / mini-suspoemulsions preferably being in their disperse phases in terms of material differ.
• the targeted coalescence of the mini-emulsion droplets (or mini-suspoemulsion droplets) is effected in the second step (emulsification step (step b)).
• the reaction of the reactants in the coalesced droplets forms a solid, in particular in the form of nanoparticles or in the form of structures on already existing nanoparticles (eg to form a shell structure).
• an amount of at least one of the emulsion phases can be removed in an optional step c); preferably, the disperse phase is removed; if appropriate, part of the continuous phase is also removed.
• This optional process step c) is preferably carried out by evaporation, e.g. by distillation.
• the coalescence of the droplets by high-pressure homogenization can be determined, in particular, by varying the emulsification pressure, the geometry of the nozzle (s), the disperse phase fraction, the reactant concentrations, the temperature and the drop size distribution of the starting mini-emulsions or starting materials. Control mini-suspoemulsions.
• the described mini-emulsions or mini-suspoemulsions may be O / W or W / O emulsions. Preference is given to using W / O emulsions (inverse emulsions).
• the continuous phases and the disperse phase of the two starting mini-emulsions / mini-suspoemulsions used as the main constituent preferably contain the same liquid, but they may also contain different liquids which are homogeneously miscible with one another.
• the mini-emulsions and / or minisuspoemulsions are preferably W / O emulsions comprising an aqueous disperse phase.
• the mini-emulsions and / or minisuspoemulsions are W / O emulsions containing an aqueous disperse phase, in which in each case at least one reactant is dissolved.
• Preference is given to using non-polar, organic solvents or mixtures thereof as the continuous phase; in particular, the continuous phase is formed by alkanes.
• W / O or O / W emulsions are used in the present invention containing an aqueous phase and a phase containing one or more organic solvents or monomers, these liquids are selected from the group C 5 -C 50 alkanes , vegetable and animal oils, silicone oils, paraffin, triglycerides, monomers (for example styrene, acrylates).
• the proportion of the disperse phase of the mini-emulsions and / or mini-suspoemulsions produced in step a), based on the total amount, is in the range from 1 to 70% by weight, in particular from 5 to 50% by weight. -%, preferably in the range of 20 to 40 wt .-%.
• the disperse and / or the continuous phase contain at least one emulsifier, wherein the emulsifier is preferably initially introduced in the continuous phase.
• Emulsifiers for W / O emulsions usually have an HLB value of 3-8, emulsifiers for O / W emulsions usually have an HLB value of 8 to 18.
• the HLB value (of hydrophilic-lipophilic balance) represents a dimensionless number between 0 and 20, which makes statements about the water and oil solubility of a compound and plays an important role in the selection of emulsifiers or emulsifier mixtures.
• At least one emulsifier for W / O emulsions which may be selected from:
• Sorbitan fatty acid ester such as SPAN ® emulsifiers
• Fatty acid ester of glycerol or polyglycerol esters for example ® Mazol emulsifiers fatty acid ester of polyethylene glycol or Etylenglykol
• Amine alkoxylates for example Quadrol ® (BASF, DE),
• Copolymers and block copolymers such as poloxamers (block copolymers of propylene oxide and E- thylenoxid, Pluronic ®); Polyoxamines (block copolymers from
• Ethylene oxide and propylene oxide with ethylenediamine block Ethylene oxide and propylene oxide with ethylenediamine block); Polyisobutene polyamine polymer (Glisopal ®, BASF DE),
• steps a) and / or b) at least one W / O emulsifier added in the kontinulierlichen phases, which is selected from the group Glisopal ® (BASF, DE), Quadrol ® (BASF, DE), Pluronic ® (BASF, DE), SPAN ® emulsifiers, TWEEN ® emulsifiers, Mazol ® emulsifiers and lecithin.
• W / O emulsifier added in the kontinulierlichen phases which is selected from the group Glisopal ® (BASF, DE), Quadrol ® (BASF, DE), Pluronic ® (BASF, DE), SPAN ® emulsifiers, TWEEN ® emulsifiers, Mazol ® emulsifiers and lecithin.
• O / W mini-emulsions and / or mini-suspoemulsions are used, one or more known O / W emulsifiers can be used.
• O / W emulsifiers are common non-ionic, anionic, cationic and ampholytic emulsifiers in question.
• concentration of the emulsifier in the mini-emulsions or mini-suspoemulsions used is in the range from 0.1 to 10% by weight (based on the total emulsion), preferably in the range from 1 to 5% by weight, particularly preferably in the range of 1 to 3 wt .-%.
• the mixing of the mini-emulsions and / or mini-suspoemulsions in step b) in a high-pressure homogenizer is effected by a homogenizing nozzle having a diameter in the range from 50 to 700 .mu.m, preferably 70 to 400 .mu.m.
• the preparation of the mini-emulsions and / or mini-suspoemulsions in step a) can likewise be carried out in the high-pressure homogenizer described above or in one of the embodiments described below.
• At least one homogenizing / homogenizing device selected from the group flat nozzle, perforated diaphragm, slit diaphragm, deflecting nozzle and counter jet disperser is used in the homogenizing steps a) and / or b).
• Particular preference is given to using at least one homogenizing nozzle / homogenizing device selected from the group consisting of the perforated diaphragm, slit diaphragm and deflecting nozzle in the homogenizing steps a) and b).
• a perforated diaphragm with the diameter (hole diameter) d is shown schematically.
• At least one two-jet nozzle is used in the homogenization steps a) and / or b).
• a two-jet nozzle comprises in particular a diaphragm with two bores which are mounted at a certain angle ⁇ to the diaphragm surface (see FIG. 2a). The liquid passes through the nozzle and is split into two jets of liquid which meet behind the bore exits.
• a two-jet nozzle having a diameter (hole diameter) d in the range of 50 to 700 .mu.m, preferably 50 to 100 .mu.m, and an angle ⁇ in the range of 10 ° to 60 °, preferably from 20 ° to 30 °, used.
• Figure 2a shows an embodiment of a suitable two-jet nozzle.
• the mixing of the mini-emulsions and / or mini-suspoemulsions under step b) takes place in a high-pressure homogenizer, wherein at least one two-jet nozzle with a diameter (hole diameter) d in the range of 50 to 700 microns and an angle ⁇ in the range of 10 ° to 60 ° is used as Homogenisierdüse.
• Mini-emulsions and / or mini-suspoemulsions under step b) in a high pressure homogenizer wherein at least one pinhole as a homogenizing with a Diameter (hole diameter) in the range of 50 to 700 microns, preferably 70 to 400 microns, is used.
• the mixing of the mini-emulsions and / or mini-suspoemulsions under step b) preferably takes place in a high-pressure homogenizer, wherein two pinhole diaphragms arranged one behind the other are used as the homogenizing nozzle, each having a diameter in the range from 50 to 700 ⁇ m.
• one or more (preferably two) pinhole diaphragms having a diameter (hole diameter) in the range from 50 to 700 .mu.m, preferably 70 to 400 .mu.m are used in the homogenization steps a) and / or b).
• Particularly preferred is a method in which the mixing of the mini-emulsions and / or mini-suspoemulsions under step b) takes place in a high-pressure homogenizer, wherein two successively arranged pinhole as homogenizer, each having a diameter in the range of 50 to 700 .mu.m, preferably 70 up to 400 ⁇ m.
• two pinhole diaphragms with diameters of 100 ⁇ m and 200 ⁇ m are used. In a further embodiment, two pinhole diaphragms with diameters of 200 ⁇ m and 400 ⁇ m are used.
• the size distribution of the droplets of an emulsion or suspoemulsion can be determined by conventional methods, for example by means of laser diffraction or dynamic light scattering.
• a parameter of the droplet size distribution is the Sauter diameter. If the total volume of the emulsion droplets were to be transformed into spheres of equal size, the total surface area of the droplets remaining the same, these droplets would have the Sauter diameter (X 1 2 ) as the diameter. It is defined by the following formula:
• a reactant in the context of the present invention is a starting material for a chemical reaction or physical conversion which, for the purposes of the invention, leads to the formation or precipitation of a solid under the given conditions.
• a precursor substance which already has a similar structure as the product, can also be referred to as a reactant.
• a reaction within the meaning of the present invention is also understood to mean the precipitation of a dissolved precursor substance by mixing with an antisolvent or by a change in the pH.
• the reactants are preferably dissolved in the disperse phase of a mini-emulsion, in particular molecularly disperse or colloidally dissolved.
• solid reactants for example in the form of nanoparticles, in the form of a mini-suspoemulsion in the present process according to the invention.
• the reaction of the reactants necessarily produces at least one solid product.
• the reactants can in particular be reacted with one another in a precipitation reaction, in a redox reaction, in an acid-base reaction or in a polymerization.
• the described method for producing nanoparticles is characterized in that the mini-emulsions or mini-suspoemulsions are W / O emulsions which contain an aqueous disperse phase in which in each case at least one Reactant is dissolved, in particular molecular disperse dissolved.
• the invention relates to a process for the preparation of nanoparticles, characterized in that the reactants contained in the disperse phases of the mini-emulsions and / or minisuspoemulsions are molecularly dispersed salts which are present in a molar concentration in the Range from 0.01 to 0.5 mol / l, and which react when mixing the mini-emulsions and / or mini-suspoemulsions in step b) to precipitate a solid.
• At least one of the reactants contained in the disperse phases of the mini-emulsions and / or minisuspoemulsions can be an acid or a base. It is preferable that one of the reactants is an acid or a base, preferably in a concentration in the range of 0.01 to 1 mol / l.
• the reactants are a water-soluble salt containing cations selected from the group of alkali metal, alkaline earth metal, noble metal (gold (Au), silver (Ag), ruthenium (Ru), rhodium (Rh), palladium (Pd), osmium (Os), iridium (Ir), platinum (Pt)), silicon (Si), tin (Sn), iron (Fe), nickel (Ni), cobalt (Co), zinc (Zn), titanium (Ti), Zirconium (Zr), yttrium (Y) and cerium (Ce), particularly preferred are salts of alkali metal, alkaline earth metal and noble metal, further preferably salts of alkali metals.
• nanoparticles can preferably be prepared selected from the group consisting of barium sulfate nanoparticles, zinc oxide nanoparticles, titanium dioxide nanoparticles, tin oxide nanoparticles and silicon dioxide nanoparticles.
• a water-soluble barium salt eg barium chloride
• a water-soluble zinc salt eg zinc sulfate
• a mini emulsion containing as disperse phase an aqueous solution of a base eg caustic soda
• water-soluble is to be understood as meaning a salt which has a solubility in water of> 10 g / l.
• the process according to the invention can be operated batchwise, for example by carrying out steps a) and b) with a time offset in the same high-pressure homogenizer. However, it is also possible to operate the process for producing nanoparticles continuously without the combination of several high-pressure homogenizers.
• the mini-emulsions and / or mini-suspoemulsions obtained in step a) can optionally be mixed in an intermediate step initially with low shear, for example with a propeller stirrer, and then brought to coalescence in a high pressure homogenizer. However, it is also possible to combine the mini-emulsions and / or mini-suspoemulsions directly in the high-pressure homogenizer.
• the temperature in carrying out the process steps is in the range of 0 0 C to 200 0 C, preferably in the range of 10 0 C to 100 0 C. In a preferred embodiment of the invention, the temperature is in the range of 20 ° C to 30 ° C ,
• the present invention also relates to nanoparticles which can be prepared or prepared according to the method described above.
• the present invention also relates to nanostructured particles prepared according to the method described above, i. H. on particles that have a structure in the nanometer range (example, core-shell particles or nanoscale areas on the particle surface).
• the present invention relates to nanoparticles which are preparable (or obtainable) by a process in which, in a first step a), two mini-emulsions and / or mini-suspoemulsions are produced, each of which contains at least one reactant the disperse phase and at least one emulsifier, and in a second step b) the mini-emulsions and / or mini-suspoemulsions thus produced are mixed in a high-pressure homogenizer.
• the present invention preferably relates to nanoparticles having a mean particle diameter in the range from 1 to 1000 nm, preferably in the range from 10 to 500 nm, very particularly preferably in the range from 10 to 200 nm.
• the nanoparticles obtainable by the process according to the invention can have a high uniformity, in particular with regard to the particle size.
• the nanoparticles can be used in the form of the directly formed mini-suspoemulsion or in the form of a nanosuspension, which can be obtained partially or almost completely by removing at least one phase of the emulsion phases.
• the disperse phase becomes part, the disperse phase is almost completely removed, or the disperse phase is removed together with a continuous phase portion.
• the nanoparticles can also be used in solid form, as can be obtained by suitable processes, eg drying, spray-drying.
• the particles produced with the aid of the process described can be used, for example, as catalysts, it being possible for the catalyst to be present in defined regions of the nanoparticle surface.
• the particles can also serve as particulate starting material for organic photovoltaics (OPV) or as controlled release systems for pharmaceutical applications and crop protection.
• OOV organic photovoltaics
• FIG. 2a the structure of a two-jet nozzle with the angle ⁇ and the hole diameter d is schematically illustrated.
• FIG. 2b a perforated diaphragm with the diameter (hole diameter) d is shown schematically.
• Barium chloride (BaCl 2 , Merck, Darmstadt) and potassium sulfate (K 2 SO 4 , Merck, Darmstadt) were used as received and were subjected to no further purification. Barium chloride and potassium sulfate were dissolved in deionized water at the indicated molar concentration. In all experiments, the molar ratio b of the reactants according to equation (1) was about 5, so the reactant barium sulfate was always presented in 5-fold excess compared to potassium sulfate.
• the nonionic emulsifier Glissopal ® EM-23 (BASF SE, Ludwigshafen, Germany) was added to the continuous phase.
• the emulsifier concentration was 3% by weight.
• the aqueous solutions of BaCl 2 and K 2 SO 4 were each mixed with n-decane. Before the actual high-pressure homogenization step, the mixtures thus obtained were stirred for 2 minutes with a propeller stirrer (diameter about 6 cm) at 400 min -1 and then the mixtures were separated in a high-pressure homogenizer (M-110 Y Microfluidizer® from Microfluidics). The "microfluidizer nozzle" from Microfluidics was used.
• the two mini-emulsions obtained as described above were then mixed and stirred for two minutes (propeller stirrer, 400 rpm).
• the mini-emulsion thus obtained was used to prepare nano-suspoemulsions in Examples 3 to 6.
• Example 2 (preparation of the starting mini-emulsions in step a) - influence of the emulsifying pressure)
• the mini-emulsions were prepared as described in Example 1.
• the emulsifier concentration was 3 wt .-% in both emulsions, the disperse phase fraction 40 wt .-%. The reproducibility of the results was confirmed by repeated repetitions of the experiments.
• the Sauter diameter X 1 2 here amount to about 365 nm for the emulsion with barium chloride solution and about 475 nm with potassium sulfate as the disperse phase.
• Two emulsions with aqueous dispersion phases with barium chloride and potassium sulfate were prepared as described in Examples 1 and 2 and homogenized separately.
• the two emulsions were mixed and stirred for two minutes by means of a propeller mixer (400 min -1 ), and then the crude emulsion was emulsified on the M -1 10 Y Microfluidizer.RTM ..
• the results of the droplet size distribution before and after the emulsification step show that the emulsifying pressure, depending on the emulsion system, has a decisive influence on the coalescence rate.
• the droplet size distribution of the emulsion does not change after the second emulsification step at a pressure of less than 400 bar in comparison to the emulsion after the first emulsification step within the scope of the measurement accuracy. From an emulsification pressure of 400 bar, however, coalescence and thus an increase in the size of the drops occur noticeably.
• composition of the obtained mini-emulsions or mini-suspoemulsions were investigated by elemental analysis. For example, it was possible to exclude the possibility that at pressures below 400 bar the droplets coalesce and then be comminuted again, since the elemental analysis could only confirm the presence of barium chloride, but not that of the precipitate barium sulfate.
• FIG. 1 shows the cumulative distribution Qs (x) of the droplet sizes x (in ⁇ m) before and after the homogenization (step b) and as a function of the emulsifying pressure.
• the value Q 3 (x) indicates the sum distribution of the droplet sizes, ie the proportion of droplets of the corresponding size.
• the proportion of the disperse phase of the emulsions was varied between 20, 30 and 40 wt .-%, wherein the mass fractions of the remaining components were always kept constant.
• mini-suspoemulsions of zinc oxide nanoparticles were prepared as described in Example 3.
• the two-jet nozzle described above was used.
• FIG. 3 shows the cumulative distribution of the drop sizes x in ⁇ m after the first and second emulsification steps.
• the value Qs (x) represents the sum distribution of the droplets (fraction of droplets of the corresponding size).
• Example 8 (comparison of different homogenizing nozzles)
• barium sulfate nanoparticles were prepared as described in Example 3.
• FIG. 4 shows the sum distribution Qs (x) of the droplet sizes x in ⁇ m.

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