Method for manufacturing a material made of solid inorganic particles having a porous structure and the material made of solid inorganic particles having a porous structure obtained by said method

Abstract

The present invention relates to a method for the synthesis and manufacture of a material made of solid inorganic particles having an internal porous structure of chemical formula (I), which has a high specific surface area, and it further relates to the material made of solid inorganic particles obtained by said method. The inorganic particles of the material are nanoparticles having a porous structure and an average particle diameter of between 2 nm and 1 pm, while the pores of the particles have an average diameter of between 0.5 nm and 200 nm. The method of the invention is based on the use of bifunctional catalysts combined with compounds having a structure-directing effect for the synthesis of inorganic materials having a porous structure and a high specific surface area, without requiring the use of organic solvents and / or polymers. Advantageously, the materials of the present invention can be used to obtain hybrid materials with enhanced performance.

Description

[0001]

[0002] Process for manufacturing a solid inorganic particulate material with a porous structure and solid inorganic particulate material with a porous structure obtained by said process.

[0003] TECHNICAL SECTOR

[0004] The present invention relates to a process for the synthesis and manufacture of a solid inorganic particle material with an internal porous structure, of chemical formula (1), which has a high specific surface area, as well as to the solid inorganic particle material with a porous structure, of chemical formula (1), obtained by said process.

[0005] The process of the invention is based on the use of bifunctional catalysts of the amino acid type and their derivatives, combined with compounds with a structure-directing effect, for the synthesis of inorganic materials with a porous structure and high specific surface area, without requiring the use of polymers and / or organic solvents. Advantageously, the materials of the present invention can be applied in the production of hybrid materials with advanced performance.

[0006] Thus, the present invention offers a wide field of application for obtaining other particles with properties of interest, such as catalytic and photocatalytic properties, optical, thermal, mechanical, magnetic, electromagnetic, electrical, piezoelectric properties, with biological, cytostatic, biocidal or viricidal effects, among many other properties.

[0007] STATE OF THE PRIOR ART

[0008] Porous materials are characterized by having an internal three-dimensional structure with a certain degree of order, forming channels or pores. According to the IUPAC (Sing, KSW Reporting physisorption data for gas / solid systems with special reference to the determination of surface area and porosity (Recommendations 1984). Pure Appt. Chem. 57, 603-619 (1985)), they can be classified as microporous materials if the width or diameter of the pores is less than 2 nm, macroporous if it is greater than 50 nm, or mesoporous if it falls within this range. Among the best-known inorganic porous materials are those composed of oxides of silicon, aluminum, titanium, zirconium, among others, or a combination of them. The most representative are those presented as mesoporous silicate particles and microporous aluminosilicates of the zeolite type or zeotypes (Van Der Voort, P., Leus, K. & De Canck, E. Introduction to Porous Materials. (Wiley, 2019)).

[0009] According to Valtchev and Tosheva (Valtchev, V. & Tosheva, L. Porous nanosized particles: Preparation, properties, and applications. Chem. Rev. 113, 6734–6760 (2013)), work on porous silica (S¡O2) materials was originally directed towards the development of methods for particle size reduction. In the early 1970s, the first patent applications for lightweight silica materials containing some kind of internal structure appeared (such as patent applications US3383172A, US3493341A and US3556725A); but it was not until the end of the 20th century when the family of mesoporous silica materials emerged, after the invention of the molecular sieves MCM-41 (Beck, JS et al. A New Family of Mesoporous Molecular Sieves Prepared with Liquid Crystal Templates. J. Am. Chem. Soc. 114, 10834-10843 (1992)) and (Kresge, CT, Leonowicz, ME, Roth, WJ, Vartuli, JC & Beck, JSOrdered mesoporous molecular sieves synthesized by a liquidcrystal template mechanism. Nature 359, 710-712 (1992)).

[0010] Since these pioneering works, mesoporous materials have been the subject of great scientific and technological interest, due to their very useful properties in different fields of application. Their internal porous structure gives them a large specific surface area, much higher than expected for solid nanoparticles, and a high surface area / volume ratio (Narayan, R., Nayak, UY, Raichur, AM & Garg, S. Mesoporous silica nanoparticles: A comprehensive review on synthesis and recent advances. Pharmaceutics 10, 1—49 (2018)). This is because the surface area of ​​the internal pores is added to the external surface area of ​​the particle. For example, while solid silica particles, with a diameter of 118 nm and without an internal porous structure, have a surface area of ​​around 150 m 2g -1 In the case of mesoporous silica particles, this value increases to values ​​between 300 m 2 g -1 and 1000 m 2 g -1. ((Sigma-Aldrich. Silica nanopowder (718483) https: / / www.sigmaaldrich.com / ES / en / product / aldrich / 718483 and (Chiang, YD et al. Controlling particle size and structural properties of mesoporous silica nanoparticles using the taguchi method. J. Phys. Chem. C 115, 13158-13165 (201 1 ))). On the other hand, mesoporous materials are materials with an exceptional capacity for surface functionalization and coupling to molecules and / or nanoparticles of different nature, thanks to the versatility of the surface chemistry of silica (Vinu, A., Hossain, KZ & Ariga, K. Recent advances in functionalization of mesoporous silica. J. Nanosci. Nanotechnol. 5, 347-371 (2005)). The combination of these properties gives them an enormous adsorption, loading and dissolving capacity. J. Phys. Chem. C 115, 13158-13165 (201 1 ))). and / or targeted transport of compounds, such as drugs, fluorophores or other nanoparticles or molecules of interest (Llopis-Lorente, A., Lozano-Torres, B., Bernardos, A., Martínez-Máñez, R. & Sancenón, F.Mesoporous silica materials for controlled delivery based on enzymes. J. Mater. Chem. B 5, 3069-3083 (2017)). Furthermore, its stability over a wide range of temperatures and pH conditions allows its application in surface chemistry, as supports for catalysts and catalyzed reactions (Liu, Y.M. et al. Vanadium oxide supported on mesoporous SBA-15 as highly selective catalysts in the oxidative dehydrogenation of propane. J. Catal. 224, 417-428 (2004)), molecular sieves (Beck, J.S. et al. A New Family of Mesoporous Molecular Sieves Prepared with Liquid Crystal Templates. J. Am. Chem. Soc. 114, 10834-10843 (1992)), sensing and controlled release systems (Climent, E. et al. Controlled Delivery Systems Using Antibody-Capped Mesoporous Nanocontainers. J. Am. Chem. Soc. 131, 14075-14080). (2009)) and (Climent, E. et al. Controlled Delivery Using Oligonucleotide-Capped Mesoporous Silica Nanoparticles. Angew. Chemie Int. Ed. 49, 7281-7283 (2010)), etc.

[0011] Los principales materiales mesoporosos de sílice reportados hasta la fecha son:

[0012] - MCM-48 (Kumar, D., Schumacher, K., du Fresne von Hohenesche, C., Grün, M. & Unger, K. . MCM-41 , MCM-48 and related mesoporous adsorbents: their synthesis and characterisation. Colloids Surfaces A Physicochem. Eng. Asp. 187-188, 109-116 (2001 )),

[0013] - MCM-50 (Wang, S. & Li, H. Structure directed reversible adsorption of organic dye on mesoporous silica in aqueous solution. Microporous Mesoporous Mater. 97, 21-26 (2006)),

[0014] - SBA-1 1 (Zhao, D., Wan, Y. & Zhou, W. Ordered Mesoporous Materials. Ordered Mesoporous Materials (2013). doi : 10.1002 / 9783527647866),

[0015] - SBA-12 (Mayoral, A., Blanco, R. M. & Diaz, I. Location of enzyme in lipase-SBA-12 hybrid biocatalyst. J. Mol. Catal. B Enzym. 90, 23-25 (2013)), - SBA-15 (Zhao, D. et al. Triblock copolymer syntheses of mesoporous silica with periodic 50 to 300 angstrom pores. Science (80-. ). 279, 548-552 (1998)),

[0016] - SBA-16 (Zeleñák, V., Hornebecq, V. & Llewellyn, P. Zinc(ll)-benzoato complexes immobilised in mesoporous silica host. Microporous Mesoporous Mater. 83, 125-135 (2005)),

[0017] - KIT-5 (Kleitz, F. et al. Large Cage Face-Centered-Cubic Fm3m Mesoporous Silica: Synthesis and Structure. J. Phys. Chem. B 107, 14296-14300 (2003)),

[0018] - COK-12 (Jammaer, J., Aerts, A., D’Haen, J., Seo, J. W. & Martens, J. A. Convenient synthesis of ordered mesoporous silica at room temperature and quasi-neutral pH. J. Mater. Chem. 19, 8290-8293 (2009)) y

[0019] - HMM (Nandiyanto, ABD, Kim, SG, Iskandar, F. & Okuyama, K. Synthesis of spherical mesoporous silica nanoparticles with nanometer-size controllable pores and outer diameters. Microporous Mesoporous Mater. 120, 447-453 (2009))

[0020] Despite the wide variety of existing porous materials, there are still few examples of nanoparticles that have, simultaneously, dimensions smaller than 100 nm and pore diameters less than 5 nm, which are in high demand for certain biological and catalytic applications (Valtchev, V. & Tosheva, L. Porous nanosized particles: Preparation, properties, and applications. Chem. Rev. 113, 6734-6760 (2013)). This requirement is met by MCM-41 , whose dimensions vary from 100 to 170 nm and pore diameter around 2 nm, and HMM, with diameters from 20 to 80 nm and pore sizes between 4 and 15 nm.

[0021] A significant portion of mesoporous material synthesis methodologies are based on an adaptation of the “Stóber method” (Stóber, W., Fink, A. & Bohn, E. Controlled growth of monodisperse silica spheres in the micron size range. J. Colloid Interface Sci. 26, 62–69 (1968)). Briefly, in the presence of a catalyst in the liquid phase, hydrolysis and condensation of the corresponding oxide is promoted around a structure-directing compound, which acts as a template for the formation of a mesoporous structure. In the case of MCM-41 , nanoparticles can be obtained from the basic hydrolysis of organosilanes, such as tetraethylorthosilicate (TEOS) or tetramethylorthosilicate (TMOS), followed by condensation of silica around surfactant templates, such as hexadecyltrimethylammonium bromide (CTAB). Kresge et al. (Kresge, CT, Leonowicz, ME, Roth, WJ, Vartuli, JC & Beck, JSOrdered mesoporous molecular sieves synthesized by a liquid-crystal template mechanism. Nature 359, 710-712 (1992)) is called the “liquid crystal template mechanism”, in which silicate walls are formed between the self-ordered micelles of surfactant. Finally, to obtain the porous structure, the organic template is removed by a liquid-liquid extraction step, using acids or solvent mixtures with appropriate polarities. Another widely used strategy for this purpose consists of a calcination step at temperatures above 500 °C, although catalytic oxidation, photocatalytic oxidation, ozonolysis and supercritical extraction, among others, are also contemplated (Ghaedi, H. & Zhao, M. Review on Template Removal Techniques for Synthesis of Mesoporous Silica Materials. Energy and Fuels 36, 2424-2446 (2022)).

[0022] In order to reduce particle size, several alternative methodologies have been proposed, including:

[0023] (a) co-condensation methods, using two or more silicon sources (Kobler, J., Móller, K. & Bein, T. Colloidal suspensions of functionalized mesoporous silica nanoparticles. ACS Nano 2, 791-799 (2008));

[0024] (b) synthesis of functionalized hybrid particles, which present heteroatoms in their structure (Irmukhametova, GS, Mun, GA & Khutoryanskiy, VV Thiolated mucoadhesive and PEGylated nonmucoadhesive organosilica nanoparticles from 3- mercaptopropyltrimethoxysilane. Langmuir27, 9551-9556 (2011));

[0025] (c) the use of alternative catalysts to sodium hydroxide, such as ammonia (Ma, K., Sai, H. & Wiesner, U. Ultrasmall sub-10 nm near-infrared fluorescent mesoporous silica nanoparticles. J. Am. Chem. Soc. 134, 13180-13183 (2012)), the amines (Kobler, J., Moller, K. & Bein, T. Colloidal suspensions of functionalized mesoporous silica nanoparticles. ACS Nano 2, 791-799 (2008)) or amino acids (Nandiyanto, ABD, Kim, SG, Iskandar, F. & Okuyama, K. Synthesis of spherical mesoporous silica nanoparticles with nanometer-sized controllable pores and outer diameters Microporous Mesoporous Mater 120, 447–453 (2009).

[0026] As for strategy (c), the use of amino acids to reduce the size of silica particles has been described since 2006, applying it to the synthesis of solid particles of 12 to 23 nm in diameter (Yokoi, T. et al. Periodic arrangement of silica nanospheres assisted by amino acids. J. Am. Chem. Soc. 128, 13664-13665 (2006)). However, these nanoparticles do not present any internal porous structure, but rather form a space between the particles due to their high degree of order.

[0027] In the case of mesoporous silica HMM particles, they are synthesized in a medium composed of an octane-water mixture, using the amino acid L-lysine as a catalyst, a mixed template composed of CTAB surfactant and styrene monomer, and the polymerization initiator 2,2'-azobis(2-methylpropionamidine) dihydrochloride. Although this methodology allows controlling the particle size, it is necessary to use a second compound as a co-template, polystyrene, which is insoluble in water, which results in the inconvenience of having to work with a volatile and highly flammable organic solvent (octane) (Centers for Disease Control and Prevention. CDC - NIOSH Pocket Guide to Chemical Hazards - Octane. NIOSH Pocket Guide to Chemical Hazards https: / / www.cdc.gov / niosh / npg / npgd0470.html (2019)), which is a limiting factor for the production of the material on a large scale.

[0028] In this context, methodologies for the synthesis of spherical particles with diameters less than 100 nm, preferably around 50 nm, and pore sizes less than 5 nm, that are both simple and in line with the criteria of green chemistry, remain scarce. After an exhaustive review of the state of the art, no synthesis processes for these mesoporous nanoparticles have been found that are carried out exclusively in an aqueous medium or with a water content of at least 90%, using inexpensive, low-toxicity, and readily available reagents, and that do not use water-insoluble polymers. To the best of our knowledge, no records have been found of methodologies that simultaneously employ a single template compound and a bifunctional catalyst soluble in an exclusively aqueous medium or with a water content of at least 90%.

[0029] For all the above reasons, the applicant of the present invention detects the need to develop a new family of porous materials, using an alternative method, which solves the aforementioned drawbacks, as described below.

[0030] DESCRIPTION OF THE INVENTION

[0031] The present invention provides and claims a method for synthesizing inorganic materials with an internal porous structure. This methodology allows the synthesis of porous particles of chemical formula (1) with dimensions less than 100 nm and pore diameters less than 5 nm; however, it also allows the production of other particles of interest with different sizes and pore diameters.

[0032] S¡C>2

[0033] (1)

[0034] The present invention also contemplates the application of the synthesized porous materials in obtaining hybrid materials with new features.

[0035] The first aspect of the present invention describes a process for obtaining solid inorganic particles with a porous structure, composed of an inorganic oxide, the composition of which will be described in detail below. The present invention is defined in accordance with the set of claims accompanying this specification, such that the claimed process comprises the following steps:

[0036] - Dissolution of a reagent R2, an organic template with surfactant properties and structure-directing effect, in a polar reagent R3.

[0037] - Stirring of the solution obtained in the previous stage between 60 and 15000 rpm at a temperature between 0 °C and 100 °C.

[0038] - Self-assembly of R2 molecules in the reaction medium forming ordered structures.

[0039] - Addition of a reagent R1 with bifunctional catalytic properties and soluble in R3.

[0040] - Addition of a reagent R0, soluble in R3, where R0 is a precursor that supplies the silicon atoms of the chemical structure of the solid inorganic oxide particles with a porous structure, maintaining a stirring between 60 rpm and 15000 rpm and a temperature between 0 e C and 100 e C.

[0041] - Lysis reaction of reagent R0 catalyzed by reagent R1, obtaining an inorganic oxide, maintaining stirring between 60 rpm and 15,000 rpm and a temperature between 0 °C and 100 °C.

[0042] - Condensation reaction of the inorganic oxide around the assembled molecules of reagent R2, maintaining a stirring between 60 rpm and 15,000 rpm and a temperature between 0 °C and 100 °C.

[0043] - Formation of a 'sol-gel' suspension (where 'sol-gel' refers to 'colloidal solution-gel') maintaining a stirring between 60 rpm and 15000 rpm and a temperature between 0°C and 100 °C.

[0044] - Precipitation of the reaction product contained in the sol-gel suspension in the form of solid particles.

[0045] - Separation of solid particles from the supernatant by decantation.

[0046] - Purification of solid inorganic particles by extraction and washing with a polar mixture under centrifugation conditions.

[0047] After the purification stage, an additional organic compound removal step is carried out, mainly remnants of the organic template R2. This organic compound removal step can be thermal, catalytic, photocatalytic, or biological oxidation, using either a wet or dry process. If thermal oxidation is used, it is preferably carried out in a muffle furnace at a temperature between 400°C and 500°C. e C and 1200 e C.

[0048] This method is characterized by the use of reagents R0, R1, R2 and R3, being:

[0049] - R0 is a reagent that provides the atoms that make up the chemical structure of the porous inorganic particles used in the process. Thus, R0 is a compound or mixture of compounds that is soluble and reactive to R3, with the chemical formula (2)

[0050] (ROO) - (R01) r0i

[0051] (2) composed of a central silicon atom ROO, linked to r01 groups R01 , equal or different, where r01 is equal to 4, while the R01 groups are alkoxy groups containing from 1 to 6 carbon atoms, and may have linear, cyclic or aromatic chains, branched or not, containing or not heteroatoms to carbon (C) and hydrogen (H). Preferably, the R01 groups are linear chains. Thus, the reagent R0 is a tetraalkylorthosilicate.

[0052] - R1 is a reagent that catalyzes the lysis reaction of reagent R0, R1 being a compound or mixture of compounds of chemical formula (3)

[0053] (R11 )m - (R10) - (R12) ri2

[0054] (3) , where R10 is a hydrocarbon chain of up to 40 carbon atoms, with or without carbon and hydrogen heteroatoms, and may be branched, and whose branches may be of linear, cyclic or aromatic structure; R1 1 is a functional group of an acidic nature, preferably a carboxylic acid or its derivatives, and R12 is a functional group of a basic nature, preferably an amino group or its derivatives. The chemical structure of compound R1 is characterized in that R11 and R12 may be linked to the chain R10 in different positions. The quantities of functional groups R11 and R12 linked to the main chain may have multiplicities r11 and r12, respectively, other than one. Thus, R1 is a compound with an amino acid-type structure, and may be a natural or synthetic compound.Reagent R1 may be a mixture in different proportions of two or more compounds of formula (3) that are capable of catalyzing the lysis of reagent R0 and comply with the described characteristics.

[0055] - R2 is a reagent that acts as a structure-directing compound or template around which the oxide molecules that make up the inorganic particles to be obtained condense. Thus, the R2 molecules are capable of self-assembling in the reaction medium, forming ordered structures. Specifically, R2 is a compound or mixture of compounds soluble in R3 with the chemical formula (4)

[0056] (R21 ) r2i -(R20) - (R22)

[0057] (4)

[0058] , R20 being a group containing a polar portion, R21 a set of r21 groups of a mostly non-polar organic nature, r21 being four, and R22 a counterion. The R21 groups are hydrocarbon chains of up to 40 carbon atoms that are substituents of R20, whether identical or different. The R20 group is the polar center of the surfactant R2, a quaternary ammonium. The R21 are the substituents for the quaternary ammonium, not all necessarily identical, with multiplicity r21 , and can be linear, cyclic or aromatic chains, branched or not, containing or not heteroatoms to H and C. One of the R21 substituents is an alkyl group with twelve to forty carbon atoms, and one of the R21 groups is a longer chain than the rest of the R21 groups, this longer chain being the non-polar part of the surfactant R2.On the other hand, three of the R21 groups are alkyl groups with one to ten carbon atoms, the fourth R21 group is an alkyl group with fifteen to twenty-five carbon atoms, and the R22 group is a counterion of organic or inorganic nature, which can be mono- or polyatomic. Specifically, the reagent R2 is a tetraalkylammonium halide.

[0059] - R3 is a polar reagent that acts as a reaction medium, specifically water. Thus, the present invention offers the advantage of not requiring volatile organic solvents and / or insoluble polymers.

[0060] Based on the reagents described, the resulting compound of formula (1) presents two elements of different nature, including oxygen. Depending on the reagents RO, R1, R2 and R3 used in each experimental embodiment, the formation of different inorganic porous particles is observed, as described in the present invention.

[0061] As detailed above, the lysis reaction step of the RO reagent of the described procedure is carried out in a reaction medium whose nature is that indicated for reagent R3, under controlled conditions of temperature and agitation.

[0062] The steps of dissolution of reagent R2 in polar reagent R3, self-assembly of R2 molecules, addition of reagent R1 and reagent RO and lysis reaction of RO catalyzed by R1, condensation reaction of inorganic oxide around R2 molecules and formation of the sol-gel aqueous suspension take place at a temperature between 0 e C and 100 e C, preferably between 25 e C and 85 eC, with a stirring speed between 60 and 15,000 rpm, preferably between 200 and 2,000 rpm. These steps can be carried out under controlled pressure conditions, namely atmospheric pressure, pressure below atmospheric pressure, and pressure above atmospheric pressure, with atmospheric pressure being preferred.

[0063] As for the composition of the reaction mixture, the process of the present invention preferably uses mass ratios for the reactants, in this order R0:R1:R2:R3, expressed in the form of an interval (minimum-maximum): (10-100) : (0.1 -5) : (1 -8) : (500-2000).

[0064] According to another additional preferred embodiment, the process for obtaining the material of formula (1) may also comprise, if necessary, an additional step of adjusting the pH of the reaction mixture to a basic pH, a value greater than 8 and less than 13 being preferable. Thus, a step of adjusting the pH is carried out after the addition of R1 and before the addition of RO, to ensure that the reaction mixture has a pH in the indicated range.

[0065] The process of the invention also comprises a step for isolating and purifying the product obtained. The isolation of the synthesized particles consists of a decantation and separation step after precipitation of the product, which can be accelerated by centrifugation using methods widely known in the art.

[0066] According to a further preferred embodiment, if the centrifugal separation mentioned above is necessary for the separation and purification steps of the present process, it can be carried out under centrifugation conditions between 100 and 30,000 rcf.

[0067] In turn, the aforementioned purification step is carried out by successive extraction and washing cycles under centrifugation conditions. For the purification described in the present process, polar aqueous mixtures composed of two or more substances are preferably used. According to a preferred embodiment, the extraction and washing mixture used in the process of the present invention may be a mixture of binary or ternary composition, water-based, containing alcohols with a hydrocarbon chain of one to six carbon atoms. The centrifugation conditions used in the extraction steps may range from 100 to 30,000 rcf.

[0068] The process described in the present invention includes an additional step for removing organic compounds after the purification step, to obtain the porous inorganic material of formula (1). The methods for removing organic compounds in this additional removal step include thermal, catalytic, photocatalytic, or biological oxidation, using either a wet or dry method, as detailed above.

[0069] According to a further preferred embodiment, if necessary, the solid inorganic particles obtained are subjected to a grinding step to crush the synthesized solid material, by different mechanical means, finally obtaining the porous inorganic materials that are the object of the present invention.

[0070] A second aspect of the present invention describes that the combination of reagents R0, R1, R2 and R3, subjected to the steps described above, leads to obtaining different solid inorganic particle materials with a porous structure of chemical formula (1)

[0071] S¡02

[0072] (1)

[0073] The compound of formula (1) is characterized by the fact that its composition presents 2 elements of different nature, including oxygen, that is, it is formed by a binary combination of elements, A x EITHER 2x . where A is Yes.

[0074] A third aspect of the present invention describes the production of particles with an internal porous structure, referred to as BRES for the purpose of facilitating the distinction between the various embodiments described below. Figures 1 to 5 accompanying this specification show electron microscopy images obtained for different BRES particles (BRES-01, BRES-02, BRES-03, BRES-04 and BRES-05, by way of example), according to different embodiments of the method described in the present invention.

[0075] BRES particles can range in size from 2 nm to 1 micrometer, depending on the execution performed. The expected size ranges for different executions of this process are described in the examples attached to this specification.

[0076] A fourth aspect of the present invention describes the structure of the particles, which is characterized by having pores throughout the entire volume of the particle. This pore distribution is characterized by a worm-like visual pattern.

[0077] The porous structure of the BRES particles presented in this invention is characterized by having pores with an average diameter ranging from 0.5 to 200 nm, comprising a micro-, meso-, and / or macroporous structure, depending on the execution performed. For a specific synthesis, the pore diameter has a specific uniform average value. The expected pore size ranges for different executions of the present process are described in the Examples attached to this specification.

[0078] A fifth aspect of the present invention relates to the application of the synthesized porous materials to obtain other hybrid materials with advanced features. This application is characterized by the use of the synthesized porous particles as described herein to obtain other particles with properties of interest, such as catalytic and photocatalytic properties, optical, thermal, mechanical, magnetic, electromagnetic, electrical, piezoelectric properties, with biological, cytostatic, biocidal or viricidal effects, among many other properties, by assimilation to the applications that porous inorganic particles can have, already well known and reported in the state of the art.Such use is based on the properties of the porous materials described here, such as their porous structure, internal pore volume, large specific surface area, narrow distribution of pore diameters, etc.

[0079] BRIEF DESCRIPTION OF THE DRAWINGS

[0080] To complement the description that follows and in order to help better understand the characteristics of the invention, in accordance with the preferred examples of practical implementation thereof detailed below, a set of drawings is attached as an integral part of said description, in which the following has been represented for illustrative and non-limiting purposes:

[0081] Figure 1 shows two images at different scales of the BRES-01 particles obtained according to a first embodiment of the present invention, where the image on the left has been obtained by scanning electron microscopy and the image on the right has been obtained by transmission electron microscopy.

[0082] Figure 2 shows two transmission electron microscopy images at different scales of the BRES-02 particles according to a second embodiment of the present invention.

[0083] Figure 3 shows two transmission electron microscopy images at different scales of the BRES-03 particles according to a third embodiment of the present invention. Figure 4 shows two scanning electron microscopy images (left) and transmission images (right) of the BRES-04 particles according to a fourth embodiment of the present invention.

[0084] Figure 5 shows two images at different scales of the BRES-05 particles according to a fifth embodiment of the present invention, where the image on the left has been obtained by scanning electron microscopy and the image on the right has been obtained by transmission electron microscopy.

[0085] Figure 6 shows a schematic of the synthesis process of inorganic solid particle materials with porous structure as described in the present invention.

[0086] Figure 7 shows a graph of the Fourier transform infrared spectrum for the characterization of the chemical bonds present in the structure of a compound of formula (1), obtained according to Example 1 BRES-01 described in the present invention, where the wave number in cm has been represented on the abscissa axis. -1 and on the ordinate axis the transmittance in %.

[0087] Figure 8 shows a graph with the adsorption isotherms (data series E) and desorption (data series F) of nitrogen for the characterization of the porous structure of the solid inorganic particles BRES-01 according to Example 1 of the embodiment of the object of the present invention, where the relative pressure is represented on the abscissa axis and the absorbed quantity in cm is represented on the ordinate axis. 3 g -1 .

[0088] Figure 9 shows a transmission electron microscopy image of an example of fluorescent nanoparticles synthesized using the solid inorganic particles BRES-01 according to Example 1 of the embodiment of the object of the present invention.

[0089] Figure 10 shows a graph with the absorption spectra (data series G) and fluorescence emission (data series H) of an example of fluorescent nanoparticles synthesized using the solid inorganic particles BRES-01 according to Example 1 of the embodiment of the object of the present invention, where the wavelength in nm has been represented on the abscissa axis and the intensity (au) on the ordinate axis.

[0090] EXAMPLES

[0091] Below, some examples and figures illustrate how to prepare the porous inorganic materials of formula (1), which are not intended to limit the present invention, but rather serve to show the procedure and reagents that can be used for its preparation.

[0092] The process for obtaining porous inorganic materials as described in the present invention is outlined in Figure 6. Thus, first, R2 - a surfactant with a structure-directing effect - is dissolved in R3 (A) under stirring conditions, followed by self-assembly of R2 in the medium of R3 (B). Next, the bifunctional catalyst reagent R1 is added, followed by reagent RO, resulting in lysis of RO catalyzed by R1 in the polar medium R3 under controlled stirring and temperature conditions. Reagent R1 provides an additional spherical effect, influencing the formation of the structure of the oxide of formula (1) around compound R2 (C). Finally, the solid inorganic particles obtained are purified (D) to obtain the final product sought.

[0093] In the embodiments described below, the synthesis of solid inorganic particles with a porous structure of the material of the invention is characterized in that the compound RO is a tetraalkylorthosilicate, R1 is an amino acid, R2 is a quaternary ammonium salt, and R3 is water. The reaction occurs at a basic pH, between 8 and 11.

[0094] Example 1: Synthesis of particles called BRES-01

[0095] To prepare the particles of the first embodiment known as BRES-01, a cetrimonium halide (reagent R2, 0.3 g, 0.8 mmol) is dissolved in water (reagent R3, 150 g, 8.3 mol) at room temperature. A solution of 2,6-diaminohexanoic acid (reagent R1, 0.1 g, 0.7 mmol) is then added to this, followed by the addition of tetraethoxysilane (reagent R0, 1.5 mL) slowly. The reaction mixture is kept under stirring or vernight (a term in English referring to stirring being maintained overnight) at a temperature of 75 °C.

[0096] According to this embodiment according to Example 1, the BRES-01 particles of the present invention are obtained, which are characterized by having a diameter whose average value is between 15 and 80 nm. Preferably, the BRES-01 particles of the present invention are characterized by having an average particle size whose value is between 35 and 60 nm.

[0097] Example 2: Synthesis of particles called BRES-02

[0098] For the preparation of the particles of the second embodiment example called BRES-02, hexadecyl(methyl)ammonium bromide (reagent R2, 1 g) is dissolved in water (reagent R3, 500 g) at 25 q C. A solution of lysine monohydrochloride (reagent R1, 5 mL, 0.37 mol L) is added. -1 ) and the pH of the mixture is adjusted to 10. Tetraethylorthosilicate (reagent R0, 5 mL) is then slowly added and the reaction mixture is kept stirring overnight at 80 q C.

[0099] According to the embodiment according to Example 2, BRES-02 particles are obtained, characterized in that they have sizes ranging from 10 to 50 nm. Preferably, the BRES-02 particles of the present invention are characterized in that they have an average particle size ranging from 15 to 30 nm.

[0100] Example 3: Synthesis of particles called BRES-03

[0101] For the preparation of BRES-03 particles, a hexadecylmethylammonium halide (reagent R2, 1 g, 2.3 mmol) is dissolved in water (reagent R3, 450 g, 25 mol) at 37 q C. A solution of 2-amino-5-guanidinopentanoic acid (reagent R1, 5 mL, 3.7 mmol L) is then added. -1 ) and then tetraethylorthosilicate (reagent R0, 5 mL) is slowly added. The reaction mixture is kept under stirring for 12 h at 80 q C.

[0102] According to the embodiment according to Example 3, BRES-03 particles are obtained, characterized by having sizes ranging from 5 nm to 1 micron. Preferably, the BRES-03 particles of the present invention are characterized by having an average particle size between 400 and 700 nm. Example 4: Synthesis of particles designated BRES-04

[0103] For the preparation of BRES-04 particles, cetyltrimethylammonium bromide (reagent R2, 0.3 g) is dissolved in water (reagent R3, 150 g) at 25 q C, together with arginine (reagent R1, 5 mmol L -1 ). Slowly, tetramethylorthosilicate (reagent R0, 1 mL) is added under stirring at 75 °C, and the system is kept stirring overnight.

[0104] According to the embodiment according to Example 4, BRES-04 particles are obtained, characterized by having sizes ranging from 2 to 100 nm. Preferably, the BRES-04 particles of the present invention are characterized by having an average particle size between 10 and 50 nm.

[0105] Example 5: Synthesis of particles called BRES-05

[0106] For the preparation of BRES-05 particles, a cetyltrimethylammonium halide (reagent R2, 0.2 g, 0.6 mmol) is dissolved in water (reagent R3, 100 g, 5.6 mol) at 25 qC. Next, a lysine solution (reagent R1, 0.7 g) is added and, slowly, tetramethoxysilane (reagent R0, 0.7 mL, 4.5 mmol) is added under stirring at 70 °C and the system is kept stirring overnight.

[0107] According to the embodiment according to Example 5, BRES-05 particles are obtained, which are characterized in that they can have sizes from 2 nm to 1 micrometer. Preferably, the BRES-05 particles of the present invention are characterized by having an average size greater than 100 nm.

[0108] According to an embodiment according to Examples 1 to 4, the porous structure of the particles designated BRES-01, BRES-02, BRES-03 and BRES-04 has pores whose average diameter may be from 0.5 to 15 nm, comprising a micro- and / or mesoporous structure. Preferably, the pore diameter of the particles BRES-01, BRES-02, BRES-03 and BRES-04 of the present invention may have an average value between 1 and 5 nm.

[0109] According to one embodiment according to Example 5, the porous structure of the particles designated BRES-05 has pores with an average size ranging from 0.5 to 200 nm, comprising a micro-, meso-, and / or macroporous structure. Preferably, the pore diameter of the porous structure of the BRES-05 particles can have an average value ranging from 2 to 50 nm.

[0110] Representative electron microscopy images obtained under conditions known in the art for particles BRES-01, BRES-02, BRES-03, BRES-04 and BRES-05 are shown in Figures 1 to 5, as an example. These results illustrate some of the particles obtained using the methodology described in the present invention and do not limit its scope.

[0111] Figure 7 shows the structural characterization of one of the materials (BRES-01) using Fourier transform infrared spectroscopy (FTIR). The presence of an absorbance band around 1000-1200 cm is observed. -1 corresponding to the tension modes of the Si—O—Si bonds, as expected, given the nature of this material.

[0112] Figure 8 shows the characterization of the mesoporous structure of one of the materials (BRES-01) by porosimetry. It is observed that the nitrogen adsorption and desorption isotherm profile is consistent with that reported for other mesoporous materials (Kumar, D., Schumacher, K., du Fresne von Hohenesche, C., Grün, M. & Unger, K. MCM-41 , MCM-48 and related mesoporous adsorbents: their synthesis and characterisation. Colloids Surfaces A Physicochem. Eng. Asp. 187-188, 109-116 (2001 )), (Nandiyanto, A. B.D., Kim, S. G., Iskandar, F. & Okuyama, K. Synthesis of spherical mesoporous silica nanoparticles with nanometer-size controllable pores and outer diameters. Microporous Mesoporous Mater. 120, 447-453 (2009)).

[0113] Isolation and purification of porous materials

[0114] Following condensation of the oxide particles of chemical formula (1), as described in the present invention, the formation of a solid-liquid suspension is observed. The solid phase is then separated and successive washes are carried out with a polar liquid mixture to extract the template molecules.

[0115] Example 6: Particle Isolation and Purification - Mode 1 The synthesized porous particles are isolated by decantation of the liquid phase. The solid phase is distributed into centrifuge tubes and the tube volume is completed with a water-ethanol mixture (1:1). The tube is then centrifuged at 20,000 rcf, and the supernatant is separated and discarded. This process is repeated several times (2-5) until the supernatant is observed to no longer contain any residue of reagent R2.

[0116] Example 7: Particle Isolation and Purification - Mode 2

[0117] The synthesized porous particles are separated from the liquid phase by centrifugation. The reaction mixture is transferred to centrifuge tubes and centrifuged at 8960 rcf, separating and discarding the supernatant. The volume of the centrifuge tube is then completed with a water-methanol mixture (1:1) and centrifuged again, as in the previous step. This process is repeated successively (2-5 times) until the supernatant is observed to no longer contain traces of reagent R2.

[0118] Removal of organic compounds from porous materials

[0119] As detailed above, after the synthesis and purification of the porous particles as described in the present invention, an additional step is performed to eliminate the organic compounds used in the synthesis. This can be achieved by thermal, oxidative, catalytic, or biological oxidation.

[0120] Example 8: Elimination of organic compounds

[0121] After purification of the porous particles, following a methodology similar to that described in Example 6, the material is left to stand overnight in a vacuum Scheibler desiccator. The solid is then calcined in a muffle furnace at 555 °C for 5 h. After cooling, the product is stored in a desiccator.

[0122] Figures 9 and 10 exemplify the application of the porous materials described in the present invention to obtain fluorescent nanoparticles by means of the quantum confinement effect of nanocrystals within the pores of the particle. A representative electron microscopy image obtained under conditions known in the art is included, and the fluorescence absorption and emission spectra of the fluorescent particles synthesized using some of the porous particles described in the present invention are also presented. Finally, Table 1 exemplifies some properties of the porous materials obtained, called BRES-01, according to the process described in the present invention, such as the specific surface area, specific volume, particle size, and average pore diameter.

[0123] Table 1: Average values ​​of properties of representative porous inorganic materials, obtained according to the process described in the present invention.

[0124] Property Value

[0125] Particle size 40 nm

[0126] Pore ​​diameter 2.8 nm

[0127] Surface area 500 m 2 g -1

[0128] Pore ​​volume 0.4 cm 3 g -1

Claims

CLAIMS 1 § . Process for manufacturing a solid inorganic particle material with a porous structure of chemical formula (1) SiOs (1) comprising the following stages: - Dissolution of a reagent R2, with surfactant properties and structure-directing effect, in a polar reagent R3. - Stirring the solution obtained in the previous stage between 60 and 15000 rpm at a temperature between 0 e C and 100 e C. - Self-assembly of R2 molecules in the reaction medium forming ordered structures. - Addition of a reagent R1 with bifunctional catalytic properties and soluble in R3. - Addition of a reagent R0, soluble in R3, where R0 is a precursor that supplies the silicon atoms of the chemical structure of the solid inorganic particles with a porous structure, maintaining a stirring between 60 rpm and 15000 rpm and a temperature between 0 e C and 100 e C. - Lysis reaction of R0 catalyzed by R1 obtaining an inorganic oxide, maintaining a stirring between 60 rpm and 15000 rpm and a temperature between 0 e C and 100 e C. - Condensation reaction of the inorganic oxide around the assembled R2 molecules, maintaining a stirring between 60 rpm and 15000 rpm and a temperature between 0 e C and 100 e C. - Formation of a sol-gel suspension, maintaining a stirring rate between 60 rpm and 15000 rpm and a temperature between 0 e C and 100 e C. - Precipitation of the reaction product contained in the sol-gel suspension in the form of solid particles. - Separation of solid particles from the supernatant by decantation. - Purification of solid particles by extraction and washing with a polar mixture under centrifugation conditions. - Additional removal of organic compounds, where said organic compound removal step is a thermal, catalytic, photocatalytic or biological oxidation by wet or dry means. And where - RO is a reagent with the chemical formula (ROO) - (RO1 ) r oi (2) composed of a central atom ROO of silicon (Si), linked to rO1 groups R01 , equal or different, where rO1 is equal to 4, while the R01 groups are alkoxy groups containing from 1 to 6 carbon atoms. - R1 is a natural or synthetic compound or mixture of compounds with an amino acid-type structure. - R2 is a tetraalkylammonium halide. - R3 is water that acts as a reaction medium. 2 a . Method for manufacturing a solid inorganic particle material with a porous structure, according to claim 1 a , characterized in that R1 is lysine, lysine monohydrochloride or arginine. 3 a . Method for manufacturing a solid inorganic particle material with a porous structure, according to claim 1 a , characterized in that R2 is hexadecyltrimethylammonium bromide. 4 a . Method for manufacturing a solid inorganic particle material with a porous structure, according to claim 1 a, characterized in that the steps of dissolution of reagent R2 in polar reagent R3, self-assembly of R2 molecules, addition of reagent R1 and reagent RO and lysis reaction of RO catalyzed by R1, condensation reaction of inorganic oxide around R2 molecules and formation of the aqueous sol-gel suspension take place at a temperature between 25 e C and 85 e C and atmospheric pressure, with a stirring speed between 200 and 2000 rpm. 5 a . Method for manufacturing a solid inorganic particle material with a porous structure, according to claim 1 a , characterized by comprising a stage additional pH adjustment after the addition of R1 and before the addition of RO, so that the reaction mixture has a pH between 8 and 13. 6 a . Method for manufacturing a solid inorganic particle material with a porous structure, according to claim 1a , characterized in that the reagents R0:R1:R2:R3 are used in the mass proportions of (10-100) : (0.1 -5) : (1 -8) : (500-2000). 7 a . Method for manufacturing a solid inorganic particle material with a porous structure, according to claim 1 a , characterized in that the stages of separation and purification of solid inorganic particles are carried out by applying centrifugation between 100 and 30,000 rcf. 8 a . Method for manufacturing a solid inorganic particle material with a porous structure, according to claim 1 a , characterized in that the polar mixture of the purification stage of solid inorganic particles is a binary or ternary mixture, based on water, containing alcohols with a hydrocarbon chain of up to 6 carbon atoms. 9 a. Method for manufacturing a solid inorganic particle material with a porous structure, according to claim 1 a , characterized in that thermal oxidation is carried out in a muffle furnace at a temperature between 400 e C and 1200 e C. 10 a . Method for manufacturing a solid inorganic particle material with a porous structure, according to claim 1 a , characterized in that the solid inorganic particles obtained are subjected to a grinding stage. 11 a . Method for manufacturing a solid inorganic particle material with a porous structure, according to claim 1 a , characterized in that the reagent R0 is tetraethylorthosilicate or tetramethylorthosilicate. 12 a. Method for manufacturing a solid inorganic particle material with a porous structure, according to claim 1, characterized in that the R01 groups are linear chains. 13 a . Solid inorganic particulate material with a porous structure of chemical formula (1) YES2 (1) obtained according to the method of any of the preceding claims, characterized in that the inorganic particles are nanoparticles with a porous structure with an average particle diameter between 2 nm and 1 | im, while the pores of the particles have an average diameter between 0.5 nm and 200 nm. 14 a . Solid inorganic particle material with a porous structure, according to claim 13 a , characterized by the fact that the pores of the particles have an average diameter between 0.5 nm and 15 nm. 15 a. Solid inorganic particle material with a porous structure, according to claim 13 a , characterized by the fact that the pores of the particles have an average diameter between 1 nm and 5 nm. 16 a . Solid inorganic particle material with a porous structure, according to claim 13 a , characterized by the fact that the pores of the particles have an average diameter between 2 nm and 50 nm. 17 a . Solid inorganic particle material with a porous structure, according to claim 13 a , characterized in that it is obtained from tetraethoxysilane, 2,6-diaminohexanoic acid and a cetrimonium halide dissolved in water, such that the particles have an average diameter between 15 nm and 80 nm, while the pores of the particles have an average diameter between 0.5 nm and 15 nm. 18 a. Solid inorganic particle material with a porous structure, according to claim 13 a , characterized in that it is obtained from tetraethylorthosilicate, lysine monohydrochloride and hexadecyl(thmethyl)ammonium bromide dissolved in water, such that the particles have an average diameter between 10 nm and 50 nm, while the pores of the particles have an average diameter between 0.5 nm and 15 nm. 19 a . Solid inorganic particle material with a porous structure, according to claim 13 a , characterized in that it is obtained from tetraethylorthosilicate, 2-amino-5-guanidinopentanoic acid and a hexadecyl(trimethyl)ammonium halide dissolved in water, in the form that the particles have an average particle size between 400 nm and 700 nm, while the pores of the particles have an average diameter between 0.5 nm and 15 nm. 20 a. Solid inorganic particle material with a porous structure, according to claim 13 a , characterized in that it is obtained from tetramethylorthosilicate, arginine and cetyltrimethylammonium bromide dissolved in water, such that the particles have an average particle size between 2 nm and 100 nm, while the pores of the particles have an average diameter between 0.5 nm and 15 nm. 21 a . Solid inorganic particle material with a porous structure, according to claim 13 a , characterized in that it is obtained from tetramethoxysilane, lysine and a cetyltrimethylammonium halide dissolved in water, such that the particles have an average particle size from 2 nm to 1 |im, while the pores of the particles have an average diameter between 0.5 nm and 200 nm. 22 a. Use of the solid inorganic particle material with porous structure according to claims 13 a at 21 a for the synthesis of fluorescent nanoparticles.

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