WO2012110995A1 - Microparticules noyau-enveloppe de silice - Google Patents

Microparticules noyau-enveloppe de silice Download PDF

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Publication number
WO2012110995A1
WO2012110995A1 PCT/IE2012/000007 IE2012000007W WO2012110995A1 WO 2012110995 A1 WO2012110995 A1 WO 2012110995A1 IE 2012000007 W IE2012000007 W IE 2012000007W WO 2012110995 A1 WO2012110995 A1 WO 2012110995A1
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Prior art keywords
shell
silica
core
porous
microparticle
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PCT/IE2012/000007
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English (en)
Inventor
Jennifer Mary COAKLEY
John Paul Hanrahan
John Joseph HOGAN
Trevor Richard Spalding
Joseph Michael TOBIN
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Glantreo Limited
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Publication of WO2012110995A1 publication Critical patent/WO2012110995A1/fr

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    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B33/00—Silicon; Compounds thereof
    • C01B33/113—Silicon oxides; Hydrates thereof
    • C01B33/12—Silica; Hydrates thereof, e.g. lepidoic silicic acid
    • C01B33/16—Preparation of silica xerogels
    • 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
    • B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
    • B01J20/281—Sorbents specially adapted for preparative, analytical or investigative chromatography
    • B01J20/286—Phases chemically bonded to a substrate, e.g. to silica or to polymers
    • B01J20/287—Non-polar phases; Reversed phases
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
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    • B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
    • B01J20/30—Processes for preparing, regenerating, or reactivating
    • B01J20/32—Impregnating or coating ; Solid sorbent compositions obtained from processes involving impregnating or coating
    • B01J20/3202—Impregnating or coating ; Solid sorbent compositions obtained from processes involving impregnating or coating characterised by the carrier, support or substrate used for impregnation or coating
    • B01J20/3204—Inorganic carriers, supports or substrates
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    • B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
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    • B01J20/32—Impregnating or coating ; Solid sorbent compositions obtained from processes involving impregnating or coating
    • B01J20/3231—Impregnating or coating ; Solid sorbent compositions obtained from processes involving impregnating or coating characterised by the coating or impregnating layer
    • B01J20/3242—Layers with a functional group, e.g. an affinity material, a ligand, a reactant or a complexing group
    • B01J20/3244—Non-macromolecular compounds
    • B01J20/3246—Non-macromolecular compounds having a well defined chemical structure
    • B01J20/3257—Non-macromolecular compounds having a well defined chemical structure the functional group or the linking, spacer or anchoring group as a whole comprising at least one of the heteroatoms nitrogen, oxygen or sulfur together with at least one silicon atom, these atoms not being part of the carrier as such
    • B—PERFORMING OPERATIONS; TRANSPORTING
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    • B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
    • B01J20/30—Processes for preparing, regenerating, or reactivating
    • B01J20/32—Impregnating or coating ; Solid sorbent compositions obtained from processes involving impregnating or coating
    • B01J20/3291—Characterised by the shape of the carrier, the coating or the obtained coated product
    • B01J20/3293—Coatings on a core, the core being particle or fiber shaped, e.g. encapsulated particles, coated fibers
    • 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
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    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B33/00—Silicon; Compounds thereof
    • C01B33/113—Silicon oxides; Hydrates thereof
    • C01B33/12—Silica; Hydrates thereof, e.g. lepidoic silicic acid
    • C01B33/14—Colloidal silica, e.g. dispersions, gels, sols
    • C01B33/146—After-treatment of sols
    • C01B33/149—Coating
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    • 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
    • C09C1/28—Compounds of silicon
    • C09C1/30—Silicic acid
    • C09C1/3063—Treatment with low-molecular organic compounds
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
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    • C09C1/00—Treatment of specific inorganic materials other than fibrous fillers; Preparation of carbon black
    • C09C1/28—Compounds of silicon
    • C09C1/30—Silicic acid
    • C09C1/3081—Treatment with organo-silicon compounds
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    • C09C1/00—Treatment of specific inorganic materials other than fibrous fillers; Preparation of carbon black
    • C09C1/28—Compounds of silicon
    • C09C1/30—Silicic acid
    • C09C1/309—Combinations of treatments provided for in groups C09C1/3009 - C09C1/3081
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    • C01P2004/80—Particles consisting of a mixture of two or more inorganic phases
    • C01P2004/82—Particles consisting of a mixture of two or more inorganic phases two phases having the same anion, e.g. both oxidic phases
    • C01P2004/84—Particles consisting of a mixture of two or more inorganic phases two phases having the same anion, e.g. both oxidic phases one phase coated with the other
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Definitions

  • the invention relates to a process for preparing core shell silica microparticles and core shell hybrid silica microparticles.
  • the microparticles are especially useful in chromatography, such as liquid chromatography
  • DE-19530031 (Unger et al) describes a process for forming templated core-shell suborn silica particles comprising a porous layer on the surface of a non-porous silica core by sol-gel polycondensation of an alkytrialkoxysilane in an ammonia-water solution in which ammonia acts as a catalyst and alkyltrialkoxysilane functions as porogen.
  • the average particle size produced by this process is less than lOOOnm (1.0 ⁇ ).
  • JP2006-34789 describes a process for making templated core-shell silica particles that employs alkylammonium halide.
  • the maximum size of the core-shell silica particles described is 1.2 ⁇ .
  • JP2006-34789A describes an approach of stacking a single shell layer comprising of silica onto a nonporous silica surface, in the presence of a quaternary ammonium halide as a templating agent to produce the core-shell silica.
  • HaloTM Fused-Core ® particles
  • the 2.7 ⁇ silica particles are described as consisting of 1.7 ⁇ non-porous particles and 0.5 ⁇ porous shell.
  • the Halo chromatographic column is described as generating an efficiency of 250,000 N/m equivalent to reduce plate height minimum (/? m j n ) of 1.5 for small molecules when packed in a 4.6 mm I.D. columns.
  • Phenomenex Inc. offered silica core-shell particles of 2.6 and 1.7 ⁇ particle diameters.
  • the 2.6 ⁇ particles were described as consisting of a 1.9 ⁇ nonporous particles coated with a 0.35 ⁇ porous layer of aggregated colloidal silica.
  • the 1.7 ⁇ particles were described as consisting of a 1.3 ⁇ solid-core covered with a 0.25 ⁇ porous layers of silica. These columns are currently commercialised as inetexTM.
  • US2009/0053524A1 (Yamanda-Ashai) describes a process for making core shell silica particles that utilises alkyl ammonium halide surfactant.
  • dodecyl amine is used as a surfactant template to produce templated core-shell sub ⁇ m silica particles.
  • Particles having a shell thickness of 0.15 ⁇ on the surface of a non-porous silica core having a diameter of 1.0 ⁇ , are described.
  • the particles have a pore size of 2.5 nm, pore volume of 0.09 mL/g and a maximum particle size of 1.3 ⁇ .
  • the morphology of these core-shell particles especially pore volume and pore size, are not ideal for use as a chromatographic packing material.
  • Yoon et. al. (J.Mater.Chem 17 (2007) 1758) describe a process for preparing core-shell nanosized silica using a similar approach to that described in JP2006-34789 but using a different chain length of alkyl ammonium halide.
  • the particles described by Yoon et. al are so small that, they would pose a significant difficulty when packed in a column to be used for conventional or ultra high pressure liquid chromatography separation.
  • the consequences will chiefly be the enormous back pressure encountered, such that no commercial LC or UPLC instrument available today could operate on such a material when packed in a column.
  • step (a) is repeated a plurality of times.
  • the mixed surfactant may comprise a cationic surfactant and a non-ionic surfactant.
  • the cationic surfactant may be an alkyl ammonium tosylate.
  • the alkyl ammonium tosylate may be selected from the group comprising: hexadecyltrimethylammonium p-tolunensulfonate; 4- chloro-N,N-diethyl-N-heptylbenzenebutanaminium tosylates (Clofilium Tosylate); ⁇ , ⁇ , ⁇ - Trimethyl-4-(6-phenyl- 1 ,3 ,5-hexatrien- 1 -yl)phenylammonium p-toluenesulfonate; and tetrabutylammonium p-toluenesulfonate.
  • the mixed surfactant solution may comprise a tri- block co-polymer.
  • the tri-block co-polymer may be a difunctional pluronic block co-polymer.
  • the tri-block co-polymer may comprise a polyethylene oxide (PEO) and/or a polypropylene oxide (PPO) unit.
  • the tri-block co-polymer may have a terminal HO- group at one or both ends of the PEO group.
  • the triblock co-polymer may comprise the formula:
  • x is an integer between 5 and 106;
  • the tri-block co-polymer may be PEO 20 PPO 70 PEO 20 and/or PEO 106 PPO 70 PEOi 06
  • the tri- block co-polymer may act as a steric stabiliser to prevent aggregation of particles during the growth of silica shell.
  • the alkoxy silica precursor may be one or more of tetrapropyl ortho silicate (TPOS), tetrabutyl ortho silicate (TBOS) tetraethyl ortho silicate (TEOS), and tetramethyl ortho silicate (TMOS).
  • TPOS tetrapropyl ortho silicate
  • TBOS tetrabutyl ortho silicate
  • TEOS tetraethyl ortho silicate
  • TMOS tetramethyl ortho silicate
  • the organic alkoxy silane precursor may have the general formula
  • R is an organic radical
  • X is a hydrolysable group
  • n l or 2;
  • z is an integer from 1 to 30.
  • the organo alkoxy silane precursor may be selected from triethoxymethylsilane (TEMS) and bis- l,2-(triethoxysilyl) ethane (BTSE).
  • TMS triethoxymethylsilane
  • BTSE bis- l,2-(triethoxysilyl) ethane
  • the molar ratio of alkoxy silica precursor to organo alkoxy silane precursor may be between about 90: 10 to about 40:60.
  • the molar ratio of alkoxy silica precursor to organo alkoxy silane precursor may be between about 90: 10 to about 75:25.
  • Ammonia may be added to the growth step to form the basic pH conditions.
  • the oil- in -water emulsion comprises one or more of an aliphatic alkane, a cycloalkane, or aromatic hydrocarbon of the formula:
  • n is an integer between 6 to 12;
  • the oil unit of the oil-in-water emulsion system may comprise one or more of decane, trimethylbenzene, and cyclooctane.
  • the oil-in-water emulsion may comprise ammonium iodide.
  • Step (a) may be repeated between 2 and 100 times.
  • Step (a) may be performed at a temperature between about 25 °C to about 55 °C.
  • Step (a) may take between about 1 hour and about 24 hours.
  • the microparticles may be hydrothermally treated at a temperature of from about 60 °C to about 150 °C.
  • the microparticles may be hydrothermally treated from about 1 hour to about 72 hours.
  • the hydrothermally treated microparticles may be dried prior to calcination.
  • the microparticles may be dried under vacuum.
  • the microparticles may be dried at a temperature of between about 98 °C to about 102 °C.
  • the microparticles may be dried for about 24 hours.
  • the microparticles may be calcined at a temperature of about 500 °C to about 600 °C to remove surfactant.
  • the microparticles may be calcined at a ramping temperature. The temperature may be ramped at a rate of between about 1 °C and about 10 °C per minute.
  • the microparticles may be calcined for between about 76 hours to about 24 hours.
  • the surfactant may be extracted from the microparticles using an alcoholiacid mixture.
  • Controlled dissolution of the microparticles may be performed in an aqueous solution of ammonia and hydrogen peroxide. Controlled dissolution of the microparticles may take place at a temperature of about 75 °C. Controlled dissolution of the microparticles may take place for between about 8 hours to about 16 hours.
  • the invention also provides a hybrid silica core-shell microparticle comprising a non-porous core with an average diameter of at least 1.4 ⁇ and a porous hybrid silica shell.
  • the invention further provides a hybrid silica core-shell microparticle comprising a non-porous core with an average diameter of about 1.4 ⁇ and a porous hybrid silica shell with an average thickness of about 0.15 ⁇ .
  • the invention further provides a hybrid silica core-shell microparticle comprising a non-porous core with an average diameter of about 1.8 ⁇ and a porous hybrid silica shell with an average thickness of about 0.4 ⁇ .
  • the invention also provides a hybrid silica core-shell microparticle comprising a non-porous core with an average diameter of about 2.5 ⁇ and a porous hybrid silica shell with an average thickness of about 0.5 ⁇ .
  • the core may be solid.
  • the core may be formed from silica.
  • the porous hybrid silica shell may contain up to about 60% carbon by weight within the silica framework.
  • the porous hybrid silica shell may contain up to about 50% carbon by weight within the silica framework.
  • the porous hybrid silica shell may contain up to about 25% carbon by weight within the silica framework.
  • the porous hybrid silica shell may contain up to about 15% carbon by weight within the silica framework.
  • the porous hybrid silica shell may contain up to about 10% carbon by weight within the silica framework.
  • the porous hybrid silica shell may have a thickness of between about 0.1 ⁇ and about ⁇ ⁇ .
  • the porous hybrid silica shell may have a thickness of between about 0.1 ⁇ and about ⁇ ⁇ .
  • the porous hybrid silica shell may comprise multiple layers of hybrid silica.
  • the microparticle may have a substantially smooth surface.
  • the pores may have an average size of between about 20A and about 300A.
  • the pores may have an average size of between about 60A and about 300A.
  • the pores may have an average size of about 80 A.
  • the microparticle may have a specific surface area from about 50m 2 /g to about 1000m 2 /g.
  • the microparticle may comprise a functional ligand attached to the shell.
  • the functional ligand may be chemically attached to the shell.
  • the functional ligand may be C8 or CI 8.
  • the invention also provides a silica core-shell microparticle with an average diameter of about 2.6 ⁇ comprising a non-porous silica core with an average diameter of about 1.8 ⁇ and a porous silica shell with an average thickness of about 0.4 ⁇ wherein the pores have an average size of about 80 A.
  • the microparticle may have a specific surface area of about 174 m 2 /g.
  • the invention further provides a silica core-shell microparticle with an average diameter of about 3.5 ⁇ comprising a non-porous silica core with an average diameter of about 2.5 ⁇ and a porous silica shell with an average thickness of about 0.5 ⁇ wherein the pores have an average size of about 80 A.
  • the microparticle may have a specific surface area of about 230 m 2 /g.
  • chromatography packing material comprising hybrid silica core-shell microparticle or silica core-shell microparticles described herein.
  • the invention also provides for the use of hybrid silica core-shell microparticles produced by the process of liquid chromatography separation.
  • the invention further provides for the use of hybrid silica core-shell microparticle or silica core-shell microparticles described herein.
  • Also described is a process for preparing silica and hybrid silica core— shell microparticles comprising the steps of: a) growing a porous silica shell from a silica precursor onto the surface of non- porous silica particles dispersed in a stabilizing mixed surfactant solution under basic pH conditions;
  • the mixed surfactant may comprise a cationic surfactant and a non-ionic surfactant.
  • the cationic surfactant is an alkyl ammonium tosylate.
  • the alkyl ammonium tosylate may be selected from the group comprising: hexadecyltrimethylammonium p-tolunensulfonate;
  • the mixed surfactant solution may comprise a tri-block co-polymer.
  • the tri-block co-polymer may be a difunctional pluronic block co-polymer.
  • the tri-block co-polymer may comprise a polyethylene oxide (PEO) and/or a polypropylene oxide (PPO) unit.
  • the tri-block co-polymer may have a terminal HO- group at one or both ends of the PEO group.
  • the triblock co-polymer comprises the formula:
  • PEO x PPO y PEO x wherein: x is an integer between 5 and 106; and y is an integer between 30 and 85.
  • the tri-block co-polymer may be PEO 20 PPO 70 PEO 20 and/or PEOi 06 PPO 70 PEO,o 6
  • the tri-block co-polymer may act as a steric stabiliser to prevent aggregation of particles during the growth of silica shell.
  • the silica precursor may be an alkoxy silica precursor.
  • the silica precursor may be one or more of tetrapropyl ortho silicate (TPOS), tetrabutyl ortho silicate (TBOS) tetraeThyl ortho sfficate ⁇ (TEOS), and tetramethyl ortho silicate (TMOS).
  • TPOS tetrapropyl ortho silicate
  • TBOS tetrabutyl ortho silicate
  • TEOS tetraeThyl ortho sfficate ⁇
  • TMOS tetramethyl ortho silicate
  • ammonia is added to the growth step to form the basic pH conditions.
  • the oil- in -water emulsion may comprise one or more of an aliphatic alkane, a cycloalkane, or aromatic hydrocarbon of the formula:
  • the oil unit of the oil-in-water emulsion system may comprise one or more of decane, trimethylbenzene, and cyclooctane.
  • the oil-in-water emulsion may comprise ammonium iodide.
  • Step (a) may be repeated at least more than once. Step (a) may be repeated between 2 and 100 times.
  • step (a) is performed at a temperature between about 25 °C to about 55 °C.
  • Step (a) may take between about 1 hour and about 24 hours.
  • the particles are hydrothermally treated at a temperature of from about ⁇ 60 ⁇ °C to abouT 150 °C.
  • the particles may be hydrothermally treated from about 1 hour to about 72 hours.
  • the hydrothermally treated particles may be dried prior to calcination.
  • the particles may be dried under vacuum.
  • the particles may be dried at a temperature of between about 98 °C to about 102 °C.
  • the particles may be dried for about 24 hours.
  • the particles are calcined at a temperature of about 500 °C to about 600 °C to remove surfactant.
  • the particles may be calcined at a ramping temperature.
  • the temperature may be ramped at a rate of between about 1 °C and about 10 °C per minute.
  • the particles may be calcined for between about 76 hours to about 24 hours.
  • the surfactant is extracted from the particles using an alcohohacid mixture
  • the particles may be base etched in an aqueous solution of ammonia and hydrogen peroxide.
  • the particles may be base etched at a temperature of about 75 °C.
  • the particles may be base etched for between about 8 hours to about 16 hours.
  • a silica core-shell particle when made by a process wherein the particle has an average diameter of between about 0.9 ⁇ and about 4.0 ⁇ .
  • the core may have an average diameter of between about 0.6 ⁇ and about 2.6 ⁇ .
  • the particle may have an average diameter of about 1.7 ⁇ comprising a core with an average diameter of about 1.4 ⁇ and a shell thickness of 150nm.
  • the core is non-porous.
  • the core may be solid.
  • the shell may have an average thickness of between about 0.1 ⁇ and about ⁇ . In one case the shell is porous.
  • the pores may have an average size of between about 2nm and about 30nm.
  • the pores may have an average pore volume of between about O. lcc/g and about 2.0cc/g.
  • the particle may have a specific surface area of from about 50m 2 /g to about 1000m 2 /g.
  • the shell may comprise multiple layers of silica.
  • the surface hydroxyl groups of the particle may be more thermally stable than the surface hydroxyl groups of particles synthesized using alkyl ammonium halides. Complete dehydroxylation of the surface silanol groups may occur at temperatures in excess of 1200°C.
  • the particle may comprise a functional ligand attached to the shell.
  • the functional ligand may be chemically attached to the shell.
  • the functional ligand may be C8 or CI 8.
  • silica core-shell particle wherein the surface hydroxyl groups of the particle are more thermally stable than the surface hydroxyl groups of particles synthesized using alkyl ammonium halides.
  • silica core-shell particle wherein complete dehydroxylation of the surface silanol groups occurs at temperatures in excess of 1200°C.
  • the invention provides a hybrid silica core-shell particle.
  • hybrid silica core-shell particle having an average diameter of between about 0.9 ⁇ and about 4.0 ⁇ .
  • the porous shell of the hybrid particle may contain up to 50% carbon by weight within the silica framework.
  • chromatography packing material comprising silica core-shell or hybrid silica core shell particles of the invention.
  • the particles of the invention may be used in liquid chromatography separation.
  • Particle sizes of 2.0 ⁇ or less are more suited to UPLC instrumentation whereas particle sizes of greater than 2.0 ⁇ are more suited to 'traditional' HPLC instrumentation.
  • the invention provides a process for preparing silica and hybrid silica core shell microparticles for use in chromatography, such as liquid chromatography (LC).
  • the hybrid particles have a percentage of carbon 'in built' into the silica framework.
  • These hybrid silica particles are seen to have several advantageous over 'pure silica' particles such as increased resistance to acidic and basic solutions.
  • the invention provides a process for producing sub - 4 ⁇ microparticles for use in LC.
  • the core-shell spherical silica and hybrid silica microparticles have a thin to thick porous shell with diameters from 100 nm to 500 nm, perpendicularly grown around the surface of non-porous silica core with an average diameter of about 1.0 ⁇ to about 5.0 ⁇ such as about 1.4 ⁇ to about 2.5 ⁇ or about 600 nm (0.6 ⁇ ) to about 1500 nm (1.5 ⁇ ).
  • the core-shell microparticles may be used as packing material in chromatography such as liquid chromatography.
  • Hybrid silica particles are a member of a class of materials known as organic/inorganic hybrids. These materials contain both inorganic (such as silica) and organic (such as organosiloxane) elements and thus share the advantages of both.
  • One route to creating hybrid particles is to use a mixture of two high-purity monomers: one that forms Si0 2 units during the particle formation process and another that forms RSiOl .5 (organosiloxane) units.
  • the resulting particles contain organosiloxane groups incorporated throughout their internal and surface structure. Waters Technology (Milford, MA) have pioneered the use of fully porous hybrid silica particles for applications as stationary phases in HPLC and UPLC, so called X'bridge particles.
  • Hybrid particles offer a number of advantages (in HPLC) over pure silanous particles such as
  • the high-pH stability of silica-based reversed columns is determined by the rate of dissolution of the underlying silica particle. After dissolution has proceeded to a critical point, the packed bed abruptly collapses, causing voids which result in catastrophic loss of efficiency. Because dissolution requires access of hydroxyl ions to the silica surface, the rate of dissolution depends on the amount of underivitased silica surface. Bonded phases based on hybrid particles have an extremely low area of underivitised silica surface because of the methylsiloxane units incorporated throughout their structure. Accordingly, columns containing these particles show exceptional lifetimes in high pH mobile phases.
  • Chromatographers have an on going need to increase productivity and decrease costs. This can be accomplished by leveraging higher efficiency HPLC columns to increase analysis speed. Significant improvements have been made in the preparation of fully porous sub-2 ⁇ HPLC packing materials. These materials which provide high-efficiency separations in less time when packed in shorter columns. Unfortunately, columns packed fully porous with sub-2 ⁇ particles typically generate pressures that exceed the limits of standard HPLC instruments and require the use of ultra-high pressure HPLC systems, which can be cost-prohibitive. Core shell particles allow chromatographers to get performance comparable to sub-2-micron columns without investing in UPLC systems.
  • the optimum particle size for silica core shell for hybrid silica core shell particles is greater than about 1.7 ⁇ as this allows for columns to be utilised on traditional HPLC systems. If the core size of the hybrid silica particle is less than 1.4 ⁇ a thicker porous shell (for example thickness greater than 500nm) would have to be grown on the core particles to yield a particle with an average diameter of greater than 1.7 ⁇ . A thick porous shell (greater than 500nm) would inhibit the mass transfer properties during chromatographic separations and will lead to higher back pressure during separation, [i.e the particle will start to behave as if it were a fully porous particle.
  • alkyl ammonium tosylate surfactant is utilised in conjunction with a triblock copolymer in order to create layered porous shell structure on a solid silica particle.
  • alkyl ammonium tosylate surfactants is advantageous over alkyl ammonium halides for one or more of the following reasons:
  • alkyl ammonium tosylate surfactants have lower melting points than corresponding halide versions and are therefore easier to remove during the calcination process
  • the process produces a silica or hybrid silica material in which the hydroxyl groups on the silica or hybrid silica surface are more thermally stable than analogous silicas synthesised using alkyl ammonium halide precursors.
  • co-surfactants such as a block co-polyether with a terminal difunctional OH group to promote sterically stabilised particle system
  • a temperature above ambient conditions for example about 45 C minimizes the changes in free energy associated with the "mixing effect" of adsorbed surfactant on silica surface, and prevents agglomeration during the growth of shell particles.
  • the shell is grown on the core layer by layer.
  • a layer by layer approach allows for the controlled growth of the porous shell structure without the generation of fines (small sub lOOnm particles). This is advantageous because if a continuous process was used to form the shell, for example the continuous addition of an alkoxysilane mixture to a basic solution of core particles, a significant number of fines (small sub lOOnm particles) will be generated and the fines would have to be separated from the reaction mixture which would add several extra processing steps to the continuous process.
  • a surfactant such as alkyl ammonium tosylate
  • a mixture of silane and alkoxysilane for example BTSE, TEMS
  • the alkoxysilane contains the carbon groups that will form the hybrid portion of the hybrid silica.
  • the porogen is a surfactant and is not chemically bound into the matrix of the silica and can therefore be removed (by extraction) at very low temperature to introduce porosity into the hybrid silica shell of the particle.
  • a surfactant based approach as described herein allows the porogen (for example alkyl ammonium tosylate) to be extracted using very mild conditions such as by soxlet extraction in an alcohol :acid mixture at 60°C.
  • the use of the alkyl ammonium surfactant with an organic counter ion (such as tosylate) also allows for the facile extraction of the surfactant molecule from the hybrid silica material.
  • the low temperature used in the extraction process will not degrade any of the carbon content of the hybrid silica shell.
  • the process described herein allows for the simple tailoring of the final content of carbon in the hybrid silica shell as the ratio of alkoxysilane to silane in the reaction mixture can be adjusted to produce the desired content of carbon in the shell (for example up to about 60% by weight) without effecting the porosity of the shell.
  • the mixed surfactant system used in the process described herein drives templated layer on layer growth of the shell such that a particle with a smooth surface is formed.
  • Fig. 1 is a scanning electron micrograph image of core shell particle prepared in accordance with Example 1 ;
  • Fig. 2 is transmission electron micrograph images of a core shell particles prepared in accordance with Example 1 after (a) 1 round of silica shell growth and (b) after 7 rounds of silica shell growth;
  • Fig. 3 illustrates a particle size measurement of a core shell particles prepared in accordance with Example 1 ;
  • Fig. 4 is a graph showing the BJH adsorption and desorption isotherms of core shell particles prepared in accordance with Example 1 ;
  • Fig. 5 is a graph showing the BJH pore size measurement of core shell particles prepared in accordance with Example 1 ;
  • Fig. 6 illustrates a cross section microscopy analysis of core shell particles prepared in accordance with Example 1 ;
  • Fig. 7 illustrates particle size measurements of core shell particles prepared in accordance with Example 1 (squares), Example 4 (circles) and Example 6 (triangles);
  • Fig. 8 is a graph showing the BJH adsorption and desorption isotherms of core shell particles prepared in accordance with Example 1 (squares), Example 4 (circles) and Example 6 (triangles);
  • Fig. 9 is a graph showing the BJH pore size measurement of core shell particles prepared in accordance with Example 1 (squares), Example 4 (circles) and Example 6 (triangles);
  • Fig. 10 is a scanning electron micrograph image and its associated EDX spectrum of hybrid silica core-shell particles prepared in accordance with Example5;
  • Fig. 1 1 is a scanning electron micrograph image and its associated EDX spectrum of hybrid silica core-shell particles prepared in accordance with Example7;
  • Fig. 12 is a scanning electron micrograph image and its associated EDX spectrum of hybrid silica core-shell particles prepared in accordance with Example 8. Detailed Description
  • a template such as a cationic surfactant with a tosylate organic counter ion and a non-ionic surfactant (to act as a steric stabiliser) under basic pH, conditioned to tailor the formation of pores in a silica or hybrid silica shell layer.
  • a porous silica or hybrid silica shell is grown on a non-porous silica spheres (core) via polycondensation of an alkoxysilicate or mixed silica precursor.
  • the pore size and structure of core shell particles can be predetermined.
  • the process provides particles with a narrow size distribution. Such materials have large surface areas and are very effective for use in chromatographic, absorbent and separation applications.
  • Silica and hybrid silica core-shell particles produced by the process described herein have a solid, non-porous core. Mesopores are only present in the exterior layer (shell) of the particles.
  • the porous layer (shell) has a thickness of between about 20 nm to about 500 nm and the pore sizes and pore volume of the porous layer (shell) range from about 20 A to about 300 A and about 0.1 cc/g to about 2.0 cc/g respectively.
  • the process comprises three stages:
  • the as synthesised silica or hybrid silica particles having a porous shell surrounding the non-porous core are hydrothermally treated in an oil-in-water emulsion system to expand the size of the pores in the shell.
  • the silica or hybrid silica particles may be used as a packing material for liquid chromatography (LC).
  • the hydrothermally treated particles are subjected to a controlled dissolution step to increase the pore diameter core shell material.
  • the mesoporous shell silica particles made by the process described herein may be functionalised with a functional group such as a mono-, di- or tri-organosilane.
  • Core shell silica and hybrid silica particles in the 0.1 to 4 ⁇ range offer a number of advantages over current commercially available porous silica spheres which include:
  • Ethanol (EtOH) 100 grade was purchased from Reagacon Ireland Ltd. and was distilled over Mg/I. Water (H 2 0) was deionised water from Millipore Q water purifier (18.0 Qm). Difunctional block-co-polymer surfactants E0 2 oP0 70 E0 2 o (PI 23) average molecular weight 5800 and E0 20 P0 7 oE0 2 o (P123) average molecular weight 12600 were obtained from BASF.
  • PTFE bottles (1L) (Sigma Aldrich), magnetic stirrer and hot plate with temperature control sensor (VWR International, UK), Micromeritics Tristar II BET surface area analyser (Particle and Surface science (UK) Ltd), Philips Xpert MPD diffractometer with Cu Ka radiation, Jeol 2000 FXII transmission electron microscopy (JEOL (UK) Ltd), Inspect F scanning electron microscopy (FEI (Europe) Ltd). Micromeritics Elzone Particle Sizer II. Jeol 5510 scanning electron microscope with an Oxford Instruments Energy Dispersive X-Ray Spectroscopy detector.
  • Example 1 Synthesis of a 1.7 urn core-shell particle with a superficially porous silica shell of 150 nm on a spherical, non-porous silica surface using CTATog as a surfactant.
  • silica sol was transferred to a 1L PTFE bottle and allowed to stir at 45 °C for 20 mins.
  • a surfactant solution containing 0.297g CTATos and 1.3 g of PI 23 in 30mls dry ethanol and 53.7 mis deionised water was prepared and added to the silica sol under stirring. After 20 min of stirring, 12.3 mis of 32.5% of ammonia was added and allowed to mix for 20 mins with 3.6 mis of TEOS then being added and allowed to react for 1 hour.
  • silica particles formed were collected from the solution by centrifugation. A small portion (about 5 mg) of silica particles were removed after each reaction round and analysed for particle size increase and corresponding size distribution using dynamic light scattering (DLS) techniques. The remainder of the as produced particles were resuspended in 102 mis dry ethanol and 204 mis deionised water following the sequence in Table 1 below, the growth process was repeated 9 times. As shown below in Table 1, the total volume of each addition is increased by 6 mis.
  • DLS dynamic light scattering
  • the silica particles formed were collected from the solution by centrifugation and a pore expansion protocol was performed to expand the pores as follows:
  • Step 2 Hydrothermal pore treatment
  • the emulsion solution was used to disperse the as synthesized particles generated in step 1 and transferred to a 250 mis PTFE bottle and stirred for 1 h at 35 °C and finally transferred to a pre-heated oven at 100 °C for 72 hours.
  • the silica precipitate is separated by filtration (vacuum filtration through a Whatman 1 10 mm diameter filter paper), washed with deionised water several times and transferred to a crucible and dried for 24 h at 1 10 °C.
  • step 2 The dried silica particles generated in step 2 was calcined at 66 ⁇ ⁇ ° € to bum off the tcmplatcd surfactant to generate pores.
  • the calcination was performed in a furnace by ramping up the temperature at 5 °C /min to 600 °C and the particles were held at this temperature for 18 h. Finally the furnace was turned off and the temperature allowed to cool down to room temperature.
  • Step 4 Chemical pore etching
  • the pore size of the porous shell must be expanded above 60 A and to a maximum of 300 A, typically 90 A pore size was suitable for most separation application.
  • silica particles generated in step 3 were dispersed in a solution of 75.6 mis deionised water and placed in a heating oil to bring the temperature to 75 °C under stirring, then a mixture of 14.4 mL (5.0 wt %) aqueous ammonia and 0.56 mis (0.2 wt%) of hydrogen peroxide (H 2 0 2 ) was added via a glass syringe under stirring. The slurry was allowed to etch for 8 hours; followed by series of washing with de-ionized water and finally with methanol. The etched silica particles were dried in an oven at 150 °C for 24 hours.
  • Fig. 1 is a scanning electron micrograph image of core shell particles prepared by a method of example 1.
  • the average particle size was measured to be approx 1.7 ⁇ [composed of a 1.4 ⁇ core and a 150nm shell].
  • the SEM images confirm that the silica particles have a smooth surface free from major defects.
  • the SEM also confirms that the particles are monodispersed in nature suggesting that the process provides very tight control over particle size distribution. Little or no aggregates of particles were noted in the SEM images.
  • Fig. 2(a) is transmission electron micrograph image of a core shell particles prepared by the process of Example 1 after a single round of layer growth.
  • the average layer thickness is approx 30nm.
  • the layer thickness can be seen to be relatively uniform around the particles.
  • Figure 2(b) is a TEM image of a core shell particle prepared by the process of Example 1 after 7 rounds of silica shell growth.
  • the shell thickness was noted to be approx. 150nm. Again, the shell layer thickness can be seen to be relatively uniform around the particles.
  • Fig. 3 illustrates a particle size measurement of a core shell particles prepared by the process of Example 1 via the Electrical Zone Sensing (EZS) Technique.
  • the average particle size is noted to be 1.7 ⁇ [composed of a 1.4 ⁇ core and a 150 nm shell] which is in very good agreement with the SEM images in Figure 1.
  • the d90/dl0 (measure of monodispersivity) value was calculated to be 1.2 again confirming the monodispersed nature of the sample.
  • Fig. 4 is a graph showing the BJH adsorption and desorption isotherms of core shell particles prepared by the process of Example 1.
  • the isotherm is noted to be Type IV by IUPAC classification.
  • Fig.5 is a graph showing the BJH pore size measurement of core shell particles prepared by a process of Example 1.
  • the mean pore diameter (MPD) was calculated to be 100 A.
  • the pore size distribution profile is relatively monomodal.
  • Fig. 6 is a cross section microscopy image of core shell silica particles prepared by a process of Example 1.
  • the solid silica core of the particle can be seen quite clearly.
  • the layered porous silica shell structure is also very visible.
  • the shell thickness was noted to be approx. 150 nm, which is in agreement with the TEM data of Figure 2.
  • Fig. 7 illustrates a particle size measurement of core shell particles prepared by the process of Example 1 (squares), Example 4 (circles) and Example 6 (triangles) via the Electrical Zone Sensing (EZS) Technique.
  • the average particle size is noted to be 1.7 ⁇ [composed of a 1.4 ⁇ core and a 150 nm shell] for Example 1 , 2.6 ⁇ [composed of a 1.8 ⁇ core and a 400 nm shell] for Example 4 and 3.5 ⁇ [composed of a 2.5 ⁇ core and a 500 nm shell].
  • Fig. 8 is a graph showing the BJH adsorption and desorption isotherms of core shell particles prepared by the process of Example 1 (squares), Example 4 (circles) and Example 6 (triangles).
  • the isotherms for Examples 1 , 4 and 5 are noted to be Type IV by IUPAC classification.
  • Fig.9 is a graph showing the BJH pore size measurement of core shell particles prepared by a process the process of Example 1 (squares), Example 4 (circles) and Example 6 (triangles).
  • the mean pore diameter (MPD) was calculated toJ e 100 A for Example 1, .
  • the pore size distribution profile is relatively monomodal.
  • Example 2 Synthesis of a 1.7 um core-shell particle with a superficially porous hybrid silica shell of 150 nm on a spherical, non-porous silica surface using Clofilium as a surfactant.
  • Clofilium as a surfactant.
  • Solid non-porous silica seeds of 1.4 ⁇ diameter were synthesised according to methods described in the literature .
  • hybrid silica particles formed were collected from the solution by centrifugation. A small portion (about 5 mg) of hybrid silica particles were removed after each reaction round and analysed for particle size increase and corresponding size distribution using dynamic light scattering (DLS) techniques. The remainder of the as produced hybrid silica particles were resuspended in 102 mis dry ethanol and 204 mis deionised water following the sequence in Table 2 below, the growth process was repeated 9 times. As shown below in Table 2, the total volume of each addition is increased by 6 mis.
  • DLS dynamic light scattering
  • Table 2 A growth scheme for the formation of hybrid silica core-shell particles having a shell thickness of 150 nm.
  • the hybrid silica particles formed were collected from the solution by centrifugation and a pore expansion protocol was performed to expand the pores as described in Step 2 of Example 1.
  • Example 3 Synthesis of a 1.7 urn core-shell particle with a superficially porous (bridged) hybrid silica shell of 150 nm on a spherical, non-porous silica surface using TMA-DPH as a surfactant.
  • hybrid silica particles formed were collected from the solution by centrifugation. A small portion (about 5 mg) of hybrid silica particles were removed after each reaction round and analysed for particle size increase and corresponding size distribution using dynamic light scattering (DLS) techniques. The remainder of the as produced hybrid silica particles were resuspended in 102 mis dry ethanol and 204 mis deionised water following the sequence in Table 3 below, the growth process was repeated 9 times. As shown below in Table 3, the total volume of each addition is increased by 6 mis.
  • DLS dynamic light scattering
  • Table 3 A growth scheme for the formation of hybrid silica core-shell particles having a shell thickness of 150 nm.
  • the hybrid silica particles formed were collected from the solution by centrifugation and a pore expansion protocol was performed to expand the pores as described in step 2 of Example 1.
  • Example 4 Synthesis of a 2.6 nm core-shell particle with a superficially porous silica shell of 400 nm on a spherical, non-porous silica surface using CTATos as a surfactant.
  • CTATos CTATos
  • silica sol was transferred to a 1L PTFE bottle and allowed to stir at 45 °C for 20 mins.
  • a surfactant solution containing 0.297g CTATos and 1.3 g of P123 in 30mls dry ethanol and 53.7 mis deionised water was prepared and added to the silica sol under stirring. After 20 min of stirring, 12.3 mis of 32.5% of ammonia was added and allowed to mix for 20 mins with 2.1 mis of TEOS then being added and allowed to react for 1 hour.
  • silica particles formed were collected from the solution by centrifugation. A small portion (about 5 mg) of silica particles were removed after each reaction round and analysed for particle size increase and corresponding size distribution using dynamic light scattering (DLS) techniques. The remainder of the as produced silica's were resuspended in 102 mis dry ethanol and 204 mis deionised water following the sequence in Table 4 below, the growth process was repeated 14 times. As shown below in Table 4, the total volume of each addition is increased by 6 mis.
  • DLS dynamic light scattering
  • the silica particles formed were collected from the solution by centrifugation and a pore expansion protocol was performed to expand the pores as described in step 2 of Example 1.
  • Fig. 7 illustrates a particle size measurement of core shell particles prepared by the process of Example 4 (circles) via the ElectricalSensing Zone (ESZ) Technique compared to Example 1 (squares).
  • the average particle size for Example 4 is noted to be 2.6 ⁇ [composed of a 1.8 ⁇ core and a 400nm shell].
  • the d90/dl0 (measure of monodispersivity) value was calculated to be 1.7.
  • a secondary peak at approx 3 ⁇ was also noted in this sample. This is thought to be doublets of the existing core particle.
  • Fig. 8 is a graph which displays the BJH adsorption and desorption isotherms of the core shell particles prepared by the method of Example 4 (circles) compared to Example 1 (squares). The isotherms are noted to be Type IV by IUPAC classification.
  • Fig. 9 is a graph which displays the BJH pore size measurement of core-shell particles prepared by the process of Example 4 (circles) compared to example 1 (squares). The mean pore diameter was calculated to be 80 A. The pore size distribution profile is relatively monomodal.
  • Example 5 Synthesis of a 2.6 um core-shell particle with a superficially porous hybrid silica shell of 400 nm on a spherical, non-porous silica surface using CTATps as a surfactant.
  • silica sol was transferred to a 1L PTFE bottle and allowed to stir at 45 °C for 20 mins.
  • a surfactant solution containing 0.297g CTATos and 1.3 g of P123 in 30mls dry ethanol and 53.7 mis deionised water was prepared and added to the silica sol under stirring. After 20 min of stirring, 12.3 mis of 32.5% of ammonia was added and allowed to mix for 20 mins with 1.89 mis of TEOS and 0.21 mis of TEMS then being added and allowed to react for 1 hour.
  • the silica particles formed were collected from the solution by centrifugation. A small portion (about 5 mg) of hybrid silica particles were removed after each reaction round and analysed for particle size increase and corresponding size distribution using dynamic light scattering (DLS) techniques. The remainder of the as produced hybrid silica particles were resuspended in 102 mis dry ethanol and 204 mis deionised water following the sequence in Table 5 below, the growth process was repeated 14 times. As shown below in Table 5, the total volume of each addition is increased by 6 mis.
  • DLS dynamic light scattering
  • Table 5 A growth scheme for the formation of hybrid silica core-shell particles having a shell thickness of 400 nm.
  • the hybrid silica particles formed were collected from the solution by centrifugation and a pore expansion protocol was performed to expand the pores as described in step 2 of Example 1.
  • Fig. 10 is a scanning electron micrograph image and its associated EDX spectrum of core-shell particles prepared in accordance with this Example.
  • Example 6 Synthesis of a 3.5 um core-shell particle with a superficially porous silica shell of 500 nm on a spherical, non-porous silica surface using CTATns as a surfactant.
  • silica sol was transferred to a 1L PTFE bottle and allowed to stir at 45 °C for 20 mins.
  • a surfactant solution containing 0.297g CTATos and 1.3 g of PI 23 in 30mls dry ethanol and 53.7 mis deionised water was prepared and added to the silica sol under stirring. After 20 min of stirring, 12.3 mis of 32.5% of ammonia was added and allowed to mix for 20 mins with 1.9 mis of TEOS then being added and allowed to react for 1 hour.
  • silica particles formed were collected from the solution by centrifugation. A small portion (about 5 mg) of silica particles were removed after each reaction round and analysed for particle size increase and corresponding size distribution using dynamic light scattering (DLS) techniques. The remainder of the as produced silica particles were resuspended in 102 mis dry ethanol and 204 mis deionised water following the sequence in Table 6 below, the growth process was repeated 19 times. As shown below in Table 6, the total volume of each addition is increased by 6 mis.
  • DLS dynamic light scattering
  • Table 6 A growth scheme for the formation of core-shell particles having a shell thickness of 500 nm.
  • the silica particles formed were collected from the solution by centrifugation and a pore expansion protocol was performed to expand the pores as described in step 2 of Example 1.
  • Fig. 7 illustrates a particle size measurement of core shell particles prepared by the process of Example 6 (triangles) via the Electrical Sensing Zone (ESZ) Technique compared to Example 1 (squares) and Example 4 (circles).
  • the average particle size for Example 6 is noted to be 3.5 ⁇ [composed of a 2.5 ⁇ core and a 500 nm shell].
  • the d90/dl0 (measure of monodispersivity) value was calculated to be 1.7.
  • a secondary peak at approx 4.5 ⁇ was also noted in this sample. This is thought to be doublets of the existing core particle.
  • Fig. 8 is a graph which displays the BJH adsorption and desorption isotherms of the core shell particles prepared by the process of Example 6 (triangles) compared to Example 1 (squares) and Example 4 (circles). The isotherms are noted to be Type IV by IUPAC classification.
  • Fig. 9 is a graph which displays the BJH pore size measurement of core-shell particles prepared by the process of Example 6 compared to Example 1 (squares) and Example 4 (circles).
  • the mean pore diameter was calculated to be 80 A.
  • the pore size distribution profile is relatively monomodal.
  • Example 7 Synthesis of a 3.5 um core-shell particle with a superficially porous bridged hybrid silica shell of 500 nm on a spherical, non-porous silica surface using CTATps as a surfactant.
  • hybrid silica particles formed were collected from the solution by— centrifugation. A small portion (about 5 mg) of hybrid silica particles were removed after each reaction round and analysed for particle size increase and corresponding size distribution using dynamic light scattering (DLS) techniques. The remainder of the as produced hybrid silica particles were resuspended in 102 mis dry ethanol and 204 mis deionised water following the sequence in Table 7 below, the growth process was repeated 19 times. As shown below in Table 7, the total volume of each addition is increased by 6 mis.
  • DLS dynamic light scattering
  • Table 7 A growth scheme for the formation of hybrid silica core-shell particles having a shell thickness of 500 nm.
  • Fig. 1 1 is a scanning electron micrograph image and its associated EDX spectrum of hybrid silica core-shell particles prepared in accordance with this Example.
  • the EDX spectrum confirms the presence of Carbon (ranging from 12.07 to 15.45 weight %) on the surface of the silica spheres in accordance to the expectation for hybrid silica particles.
  • Table 8 summarises the physio-chemical properties of silica and hybrid silica core-shell particles producedin accordance with Examples 1-7.
  • the silica source used in Examples 2,3, 5 and 7 was a mixture of approx. 90: 10 TEOS/TEMS and TEOS/BTSE.
  • Examples 2,3, 5 and 7 yielded hybrid silica core shell particles and that contained approx 10% by weight Carbon.
  • Example 8 Synthesis of a 3.5 urn core-shell particle with a superficially porous bridged hybrid silica shell of 500 nm on a spherical, non-porous silica surface using CTATos as a surfactant.
  • CTATos as a surfactant.
  • solid core non-porous silica seeds of 2.5 ⁇ diameter were synthesised according to methods described in the literature 3 .
  • hybrid silica particles formed were collected from the solution by centrifugation. A small portion (about 5 mg) of hybrid silica particles were removed after each reaction round and analysed for particle size increase and corresponding size distribution using dynamic light scattering (DLS) techniques. The remainder of the as produced hybrid silica particles were resuspended in 102 mis dry ethanol and 204 mis deionised water following the sequence in Table 9 below, the growth process was repeated 19 times. As shown below in Table 9, the total volume of each addition is increased by 6 mis.
  • DLS dynamic light scattering
  • Table 9 A growth scheme for the formation of hybrid silica core-shell particles having a shell thickness of 500 nm.
  • the hybrid silica particles formed were collected from the solution by centrifugation and a pore expansion protocol was performed to expand the pores as described in step 2 of Example 1.
  • Fig. 12 is a scanning electron micrograph image and its associated EDX spectrum of core-shell particles prepared in accordance with this Example.
  • the EDX spectrum confirms the increase in Carbon content (when compared to Example 7 ranging from 23.19 to 25777 weight %) on the surface of the silica spheres in accordance to the expectation for hybrid silica particles.

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Abstract

L'invention concerne des microparticules noyau-enveloppe de silice hybrides obtenues par la mise en croissance d'une enveloppe de silice hybride poreuse à partir d'un précurseur de silice mélangé contenant un précurseur de silice alcoxy et un précurseur de silane alcoxy organique sur la surface de particules de silice non poreuses dispersées dans une solution de tensioactif mélangée de stabilisation dans des conditions de pH basique, cette étape de croissance étant répétée plusieurs fois. Les microparticules sont traitées hydrothermiquement dans un système d'émulsion huile dans eau et le tensioactif résiduel est éliminé par calcination ou extraction. Le diamètre de pores final des microparticules selon l'invention est accru par dissolution contrôlée dans une solution acide ou basique.
PCT/IE2012/000007 2011-02-16 2012-02-16 Microparticules noyau-enveloppe de silice WO2012110995A1 (fr)

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EP3151956A4 (fr) * 2014-03-11 2017-10-18 Les Innovations Materium Inc. Procédés pour la préparation de matériaux composites de silice-allotrope du carbone et leur utilisation
AU2014295912B2 (en) * 2013-07-29 2017-12-07 CoLabs Int’l., Corp. Coated particles and method of coating particles
WO2018098232A1 (fr) * 2016-11-22 2018-05-31 The University Of Akron Particules de mélanine auto-assemblées pour la production de couleurs
US10369091B2 (en) 2013-12-20 2019-08-06 Colgate-Palmolive Company Core shell silica particles and uses thereof as an anti-bacterial agent
US10434496B2 (en) 2016-03-29 2019-10-08 Agilent Technologies, Inc. Superficially porous particles with dual pore structure and methods for making the same
US10596084B2 (en) 2013-12-20 2020-03-24 Colgate-Palmolive Company Tooth whitening oral care product with core shell silica particles
EP3936226A2 (fr) 2013-06-11 2022-01-12 Waters Technologies Corporation Colonnes de chromatographie et dispositifs de séparation comprenant un matériau poreux en surface, et leur utilisation dans le cadre de la chromatographie en phase supercritique et d'autres procédés de chromatographie
CN115744925A (zh) * 2022-12-29 2023-03-07 厦门色谱分析仪器有限公司 一种采用双模板法制备单分散二氧化硅核壳微球的方法
CN115784205A (zh) * 2022-12-05 2023-03-14 北京理工大学 一种具有强吸附性和大容量空间的核壳型二氧化硅@半空心碳球、制备方法及其应用
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US11964874B2 (en) 2020-06-09 2024-04-23 Agilent Technologies, Inc. Etched non-porous particles and method of producing thereof

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US11628381B2 (en) 2012-09-17 2023-04-18 W.R. Grace & Co. Conn. Chromatography media and devices
EP3936226A2 (fr) 2013-06-11 2022-01-12 Waters Technologies Corporation Colonnes de chromatographie et dispositifs de séparation comprenant un matériau poreux en surface, et leur utilisation dans le cadre de la chromatographie en phase supercritique et d'autres procédés de chromatographie
AU2014295912B2 (en) * 2013-07-29 2017-12-07 CoLabs Int’l., Corp. Coated particles and method of coating particles
US11602495B2 (en) 2013-12-20 2023-03-14 Colgate-Palmolive Company Core shell silica particles and use for malodor reduction
US11951196B2 (en) 2013-12-20 2024-04-09 Colgate-Palmolive Company Core shell silica particles and use for malodor reduction
US10369091B2 (en) 2013-12-20 2019-08-06 Colgate-Palmolive Company Core shell silica particles and uses thereof as an anti-bacterial agent
US10596084B2 (en) 2013-12-20 2020-03-24 Colgate-Palmolive Company Tooth whitening oral care product with core shell silica particles
US11324678B2 (en) 2013-12-20 2022-05-10 Colgate-Palmolive Company Core shell silica particles and uses thereof as an anti-bacterial agent
US11400032B2 (en) 2013-12-20 2022-08-02 Colgate-Palmolive Company Tooth whitening oral care product with core shell silica particles
EP3151956A4 (fr) * 2014-03-11 2017-10-18 Les Innovations Materium Inc. Procédés pour la préparation de matériaux composites de silice-allotrope du carbone et leur utilisation
US10434496B2 (en) 2016-03-29 2019-10-08 Agilent Technologies, Inc. Superficially porous particles with dual pore structure and methods for making the same
WO2018098232A1 (fr) * 2016-11-22 2018-05-31 The University Of Akron Particules de mélanine auto-assemblées pour la production de couleurs
CN106601417B (zh) * 2016-12-26 2019-02-05 安徽工业大学 一种核壳结构铁硅软磁复合铁芯及其制备方法
CN106601417A (zh) * 2016-12-26 2017-04-26 安徽工业大学 一种核壳结构铁硅软磁复合铁芯及其制备方法
US11964874B2 (en) 2020-06-09 2024-04-23 Agilent Technologies, Inc. Etched non-porous particles and method of producing thereof
CN115784205A (zh) * 2022-12-05 2023-03-14 北京理工大学 一种具有强吸附性和大容量空间的核壳型二氧化硅@半空心碳球、制备方法及其应用
CN115744925A (zh) * 2022-12-29 2023-03-07 厦门色谱分析仪器有限公司 一种采用双模板法制备单分散二氧化硅核壳微球的方法

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