WO2006058995A2

WO2006058995A2 - Multifunctionalized mesostructured porous oxide

Info

Publication number: WO2006058995A2
Application number: PCT/FR2005/002967
Authority: WO
Inventors: Véronique DUFAUD-NICCOLAI; Laurent Bonneviot
Original assignee: Centre National De La Recherche Scientifique (C.N.R.S); Ecole Normale Superieure De Lyon
Priority date: 2004-11-30
Filing date: 2005-11-29
Publication date: 2006-06-08
Also published as: WO2006058995A3; FR2878518A1

Abstract

The invention concerns a method for making a multifunctionalized mesostructured porous oxide including the following steps: a) polycondensing in acid medium an oxide precursor in a micellar solution of an ionic surfactant; b) separating the resulting oxide from the reaction mixture; c) allowing the oxide containing surfactant micelles to react with a first functionalized agent; d) eliminating at least partly the surfactant from the functionalized oxide; e) allowing the oxide to react with a second functionalized agent; f) repeating steps d) and e) for each additional functionality; g) if required, eliminating the subsisting surfactant; and h) recovering the resulting multifunctionalized mesostructured porous oxide. The invention also concerns resulting multifunctionalized mesostructured porous oxide the uses thereof.

Description

Multifunctionalized mesostructured porous oxide

The present invention relates to multifunctional mesostructured porous oxides, especially useful as heterogeneous catalysts, and a process for their preparation. To meet the growing requirements of fine chemicals in terms of selectivity, environmental friendliness and cost of production, we seek to develop heterogeneous catalysts that combine performance, selectivity, stability and regeneration. In this context, we seek heterogeneous catalysts having a high density of active sites and a porous morphology to optimize the diffusion to these sites.

The discovery of mesostructured and porous materials having a uniform and adjustable pore size has allowed a considerable advance in this field. These materials are obtained by polycondensation, sol-gel, in the presence of surfactant, through a self-assembly.

The pore size of these materials is sufficient to accommodate organic or organometallic functional groups. These hybrid materials are therefore interesting because they combine the stability of an inorganic framework with the possibility of a molecular design of active sites. The functional groups may be introduced during the synthesis or by post-synthetic modification. It is particularly desirable to produce materials in which the functions are accessible and distributed and regularly spaced.

The patent application WO 02/16267 describes the surface modification of a mesostructured porous silica obtained by synthesis in a basic medium. The surface hydroxyl groups are partially protected by surfactant molecules prior to silylation. The regular arrangement of the surfactant molecules generated by the electrostatic repulsion of their positively charged heads is assumed to play the role of a molecular cache, to control the location of silyl groups.

However, this process has certain limitations. On the one hand, the basic synthesis of silicas is long and requires a subsequent heat treatment in an autoclave. On the other hand, the silylating compounds must release basic species so as not to displace the surfactant molecules. These compounds are not very reactive and require rather severe reaction conditions.

In addition, in the presence of several different functions, the control concerns both the nature, the distance and the number of neighboring functions.

Thus, the introduction of different functional groups during the formation of the oxide through functionalized monomers, described for example by Macquarrie et al., Stud. Surf. Sci. Catal., 2000, 129, 275 does not control the. proximity and distribution of functions in the obtained solid.

Furthermore, the mixture of two silica gels without porous structuration, containing distinct functionalizing agents, described by

Gelman et al., J. Am. Chem. Soc. 2000, 122, 11999-12000, results in materials in which the sites with the different functions are far apart.

Also, the different functions are distributed randomly or remotely in these materials.

The aim of the invention is then to propose a process for preparing a multifunctionalized mesoporous oxide, in which the different chemical functions are distributed in a controlled manner, thus creating a well-defined chemical neighborhood.

Advantageously, the proposed preparation process is rapid and can be implemented under mild conditions. The present invention takes advantage of the molecular cache principle developed for basic TS ⁺ type interfaces. Unexpectedly, it turned out that it was possible to apply this principle to acid interfaces of type I ⁺ X ^" S ⁺ and I ⁺ S ^" . On these interfaces, it is possible to use chlorinated silyl compounds, readily available and reactive.

Furthermore, it has been found that it is possible to eliminate only partially the molecular cache, thus offering the possibility of multiple functionalization in an ordered environment.

Finally, it has been found that the functionalization can be carried out under mild conditions and makes it possible to preserve the configuration of the grafted functions in advance.

The method thus makes it possible to carry out one or more additional functionalization steps, thus offering multiple possibilities of combinations. The chemical functions introduced can be very diverse in nature depending on the intended application. It may be, for example, acidic, basic, oxidizing, reducing, complexing or chiral functions.

The materials thus obtained then have the following properties: a well-defined porosity in the nanometric range;

the presence of several distinct functions with a homogeneous distribution at a molecular level; and

a wide variety of combinations of functional groups. In what follows, the expression "porous" is intended to mean a material comprising cavities allowing the movement of fluids or gas. The porosity of a material is characterized in particular by the pore size, its dispersion, and the pore volume.

The term "mesostructured" is intended to mean a material that has a periodic structure at the nanoscale, ie between 1 and 50 nm.

The term "precursor" is intended to mean any molecular reagent which, by chemical reaction, in particular with air or a solvent, or thermally, and more particularly by hydrolysis, conducts an oxide to a material in the present context. The term "micellar solution" is intended to mean a surfactant solution in which the surfactant molecules are organized, generally so as to form spheres called micelles in which the surfactant molecules are oriented in a manner similar to the surface in question. imposing by the length of their hydrophobic carbon chain a size defined in the micelle.

The expression "self-assembly" is understood to mean the spontaneous association action of formation of a material, the activation of which only takes place by placing the precursors and the surfactant molecules in contact with each other. According to a first aspect, the invention therefore relates to a process for manufacturing a multifunctionalized mesostructured porous oxide comprising the steps of: a) acid polycondensing an oxide precursor in a micellar solution of ionic surfactant leading by self-assembly to a porous mesostructured oxide containing surfactant micelles; b) separating the oxide formed from the reaction mixture; c) allowing the oxide containing surfactant micelles to react with a first functionalized agent capable of forming a covalent bond with the accessible OH groups of the oxide; d) at least partially removing the surfactant from the functionalized oxide; e) allowing the oxide to react with a second functionalized agent capable of forming a covalent bond with the OH groups released from the oxide; f) repeating steps d) and e) for each additional functionality with an appropriate functionalized agent; (g) if necessary, remove the remaining surfactant; and h) recovering the multifunctionalized mesostructured porous oxide obtained.

Silica is a particularly preferred oxide, particularly because of its strength. However, the process can be extended to the preparation of more fragile porous materials.

The oxide may therefore be more generally a metal or non-metallic oxide, mixed or pure. As metal oxide, mention may in particular be made of Al ₂ O ₃ , TiO ₂ and ZrO ₂ . Among the mixed oxides, mention may in particular be made of silica-alumina.

The oxide precursor is a compound that decomposes under the conditions of the process into the oxide, such as compounds capable of hydrolysis. Preferably, the oxide precursor is an alcoholate or a metal chloride. Specifically in the case of silica, the preferred precursor is tetraethylorthosilicate (TEOS) or tetramethylorthosilicate (TMOS).

The polycondensation reaction of the oxide precursor is of the sol-gel type. It is conducted in solution containing surfactant organized in the form of micelles. The choice of surfactant and its conditions of use determines both the porous structure, the pore size and the specific surface area.

Thus, the pore size of the oxide prepared is primarily a function of the chain length of the alkyl group of the surfactant. The use of cetyltrimethylammonium bromide makes it possible, for example, to obtain a solid with a pore diameter of approximately 3 nm.

An increase in concentration generally favors an ordered cubic or lamellar form to the detriment of a hexagonal form.

The ionic surfactant may be chosen from ionic, cationic (S ⁺ ) or anionic (S ⁺ ) surfactants, capable of forming a micellar solution in a polar solvent. These surfactants comprise in particular, among the cationic surfactants, the ammonium salts, quaternary phosphonium and, among the anionic surfactants, the salts of carboxylates and sulfonates bearing respectively at least one aliphatic group. Typically, the aliphatic group has 6 to 24 carbon atoms.

Preferably, the surfactant is selected from the group consisting of quaternary ammonium salts bearing one or two aliphatic groups containing 6 to 24 carbon atoms, the quaternary phosphonium salts bearing one or two aliphatic groups containing 6 to 24 carbon atoms. carboxylate salts having 6 to 24 carbon atoms, and sulphonate salts having 6 to 24 carbon atoms. The aliphatic groups are preferably selected from straight saturated alkyl groups.

In particular, as surfactants, the quaternary ammonium salts of the general formula are suitable

R ₄ R ₅ R ₆ R ₇ N ⁺ X where X represents fluoride, chloride, bromide, iodide, tosylate, nitrate, sulfate, and R _4, R _5, Re and R ₇ may be indifferently selected from straight and branched alkyls and alkenyls, cycloalkyls, cycloalkenyls, aryls, optionally substituted, for example with an optionally fluorinated alkyl group.

These surfactants include, in particular, tetramethylammonium, cetyltrimethylammonium and benzyltrimethylammonium salts.

The micellar solution comprises a polar solvent, such as water, alcohols, acetonitrile, dioxane, tetrahydrofuran or a mixture thereof, preferably chosen from water, alcohols and acetonitrile. A micellar solution with water as a solvent is particularly preferred.

According to one embodiment, the micellar solution further comprises an organic solvent, preferably a polar solvent, as cosolvent.

Is meant by the term "co-solvent" means a solvent present to a lesser extent, generally from 1 to 40% by volume, in particular from 5 to ^to 20% by volume relative to the total solvent present in the reaction mixture.

The cosolvent is advantageously chosen from the group consisting of straight, branched or cyclic, saturated, unsaturated and aromatic mono-, di- or polyalcohols; straight, branched or cyclic, saturated, unsaturated and aromatic ethers; straight, branched and cyclic, saturated, unsaturated and aromatic amines, amides and nitriles; esters of carboxylic acids with one of the abovementioned alcohols; straight, branched and cyclic, saturated, unsaturated and aromatic alkyl sulfoxides and mixtures thereof. More specifically, the cosolvent is selected from the group consisting of

Ethanol, ethylene glycol, tetraglyme, glycerol, tetrahydrofuran, ether, acetonitrile, dimethylformamide, N-methylformamide, methylformamide, ethyl acetate, dimethylsulfoxide and mixtures thereof.

The specialist is able, depending on the needs and conditions chosen, to adapt and select the appropriate equipment to carry out the reaction.

The polycondensation in step a) is carried out in acidic medium by acid catalysis at a pH below the isoelectric point of the oxide in formation. Thus, step a) is preferably carried out at a pH of 0 to 6. In the particular case of silica, the polycondensation is advantageously carried out at a pH of less than 2.

The presence of the micellar solution during the polycondensation leads by self-assembly to a porous mesostructured oxide containing micelles of surfactant.

The molar ratio between the oxide precursor and the micellar solution in step a) is critical for the morphology of the prepared solid. Advantageously, it is chosen so as to form a mesostructured solid of hexagonal or cubic symmetry. As an indication, the ratio of oxide precursors to surfactant may range from 1 to 20, preferably from 5 to 15 and most preferably from 7 to 9. The inorganic-surfactant interface obtained under the acidic conditions of the process may be defined by an electrical multilayer type I ⁺ XS ⁺ or I ⁺ S ^" , where I ⁺ represents positively charged protonated hydroxyl surface groups, M (OH) ₂ ⁺ with M = Si, Al, Ti, Zr in particular, and X ^" = the anion associated with the salt of the positively charged surfactant S ⁺ , for example ammonium.

In the case of negatively charged surfactants, of the sulfonate or phosphonate type, denoted S ^" , the interface does not retain the charged counter-ion positively salt and the invention, as described above, applies as in the case of positively charged surfactants, S ⁺ .

The temperature and pressure conditions are not particularly critical for the polycondensation reaction in step a). Thus, step a) can be carried out at a temperature ranging from 4 to 200 ^° C., preferably between 15 and 100 ^° C., and most preferably at room temperature. The pressure during step a) can be between 1 and 30 bar, preferably between 1 and 5 bar.

The duration of the reaction is variable and depends in particular on the reactivity of the precursor of the oxide. Generally, however, the reaction is complete within a few hours at room temperature.

After completion of the reaction, the solid is separated from the reaction mixture. The separation can be carried out by one of the usual liquid solid separation techniques, for example by means of filtration.

Preferably, the recovered porous oxide is dried, as is known per se, for example by dynamic vacuum or by inert gas sweeping. As an indication, the duration of the drying is typically from 1 to

24h, preferably between 10 and 15 h. The drying temperature is generally between 15 and 150 ^° C., preferably between 20 and 80 ^° C.

Advantageously, the solid obtained does not require aging in an autoclave at temperatures above 70 ^° C. to ensure the stability of its ordered structure.

Indeed, the subsequent steps not only introduce the features but also consolidate the structural integrity of the solid.

The solid obtained can be characterized by X-ray diffraction, nitrogen adsorption isotherms, thermogravimetry, elemental analysis infrared spectroscopy, multi-core nuclear magnetic resonance ( ¹ H, ¹³ C, ²⁹ Si) and thermogravimetry.

The first three techniques make it possible to check the macroscopic properties such as the ordered structure of the pores, the specific surface and the pore size distribution, the mass distribution "water-organic matter-inorganic matter" and, for the fourth, the empirical formula. elementary. The following techniques make it possible to probe the molecular properties of the solid-liquid or solid-gas interface.

Step c) makes it possible to introduce a first functionality in the porous mesostructured oxide obtained.

It consists in allowing the oxide containing surfactant micelles to react with a functionalized agent capable of forming a covalent bond with the accessible OH groups of the oxide. It is therefore important that the surfactant molecules are maintained within the pores. In order to optimize the spatial control of the functions introduced into the porous oxide, it is therefore preferable to choose the solvent and, more generally, the reaction conditions, taking into account this criterion.

The functionalized agent is intended to introduce a functionality by reaction with a group present on the surface of the pores without moving the surfactant molecules present in the vicinity. As mentioned above, it also has the effect of consolidating the porous solid.

It may be in particular a compound bearing, on the one hand, the desired function (s) and, on the other hand, a silane function capable of forming a covalent bond with the hydroxyl functions of the surface of the pores of the porous oxide. Thus, the functionalized agent (s) may advantageously be organosilyl compounds.

It is preferable that the molecule released by this reaction preserves surfactant molecules acting as a molecular cache. It is by moreover preferably it does not interact with the electrical interface between surfactant molecules and positively charged surface hydroxyl groups.

Therefore, it is preferred that the released molecule be neutral or acidic, preferably acidic.

The functionalizing agents of the family of organosiloxanes, which give off water during the reaction with the hydroxyl groups, and in particular the organochlorosilanes, which release the hydrochloric acid, are in this context of particular interest. These are also preferred because they have a more polar character and greater reactivity.

According to one embodiment, the functionalized agent may comprise a chiral function or a function capable of acting as a ligand.

Preferably, the functionalizing compound is an organochlorosilane of formula:

R ₁ R ₂ R ₃ Si-Cl, in which R 1, R ₂ and R ₃ are independently of each other selected from the group consisting of straight, branched and cyclic alkyl and alkenyl groups and aryl groups, optionally substituted with one or several functions alcohol, amine, imine, halide, nitro, thiol, phosphino, cyano, alkoxy, carboxy, ester and / or acetylacetonato. Preferably, R3 and / or R ₂ is a chlorine atom. It is also preferred that

R ₁ and optionally R ₂ are an alkyl group having 1 to 4 carbon atoms, and most preferably methyl. By way of example, the organochlorosilane may be chosen from the group consisting of trimethylchlorosilane, phenyldimethylchlorosilane, propyldimethylchlorosilane, ethyldimethylchlorosilane, vinyldimethylchlorosilane, octyldimethylchlorosilane, dodecyldimethylchlorosilane and diphenylmethylchlorosilane _. the chloromethyldimethylchlorosilane, 2- (3-cyclohexenyl) ethyldimethylchlorosilane, 3-chloropropyldimethylchlorosilane, (3-cyanopropyl) dimethylchlorosilane, (methoxy) dimethylchlorosilane, (N, N-dimethylamino) dimethylchlorosilane, (dichloromethyl) dimethylchlorosilane, 5-hexenyldimethylchlorosilane, 3- (methacryloxypropyl) dimethylchlorosilane.

The dichlorosilanes and trichlorosilanes of the R ₁ R ₂ SiCl ₂ and R ₁ SiCl _{3 type} may also be suitable. The preferred functionalizing agent being of organochlorosilane type R ₁ R ₂ RaSiCl and more particularly chosen from the class of organodimethylchlorosilanes of formula R ₁ (CHs) ₂ SiCl.

Alternatively, organosiloxane compounds may also be used as the functionalizing agent. These compounds, however, react more difficult by opening their siloxane bridge Si-O-Si. The reaction releases water, which does not change the pH and therefore does not affect the charge density on the oxide ensuring the retention of the surfactant acting as molecular cache.

The functionalizing agent can therefore be an organosiloxane of general formula:

wherein R ₁ , R ₂ , R ₃ are independently of each other as defined above.

The solvent allowing the solution of the functionalizing agent to be dissolved is preferably not very polar so as to avoid the displacement of the surfactant molecules. Preferably, the reaction of the oxide with the functionalized agent is carried out in an aprotic apolar solvent. The solvent may be selected from the group consisting of petroleum ethers, optionally alkylated aromatic hydrocarbons, straight, branched or cyclic alkanes and alkenes having 4 to 18 carbon atoms, and mixtures thereof. Suitable solvents include toluene, benzene, xylenes, cyclohexane, n-hexane, and more generally substituted alkanes and aryls, with toluene being most preferred. The functionalization reaction is carried out on the solid resulting from step b) at temperatures between 4 and 200 ^° C. and preferably at temperatures ranging from 15 to 110 ^° C.

It is preferred to carry out the reaction at low temperature, and particularly at room temperature, in order to further preserve surfactant molecules acting as a molecular cache.

The functionalized solid obtained is characterized by the same techniques described above.

Moreover, the retention rate of the surfactant molecules inside the pores is controlled by quantitative determination of the reaction medium after filtration. For example, in the case of quaternary ammoniums, this assay involves precipitation by potassium dichromate.

Depending on the desired number of functionalities of the porous solid, step d) consists in totally or partially removing the surfactant from the functionalized oxide. Thus, if it is desired to introduce two functionalities, the complete removal of the surfactant will be carried out.

In this step, the molecular cache is removed using a solvent, thus releasing the surface hydroxyl groups, which will then be available for reaction with a functionalizing agent in the next step.

The functionalized porous solid is then treated either by successive washings of several cycles, preferably three, or by continuous extraction in the presence of a polar solvent. As polar solvent, there may be mentioned, for example, alcohols, acetonitrile, dioxane, tetrahydrofuran or their mixtures, ethanol being preferred.

The washes are carried out at temperatures of 10 to 110 ⁰ C, preferably 20 to 85 ⁰ C, a low temperature being preferred.

Maintaining the solid structuring integrity can be controlled at this step by X-ray diffraction. The efficiency of the removal of the molecular cache can be demonstrated by infrared spectroscopy. The amount of surfactant released is determined by assaying with potassium dichromate as previously mentioned.

In the case of introduction of three or more functions, the molecular cache is partially removed only. This will make it possible to free some of the hydroxyl groups to carry out the second functionalization and preserve another part available for subsequent functionalizations.

The total removal of the surfactant can be carried out with a polar solvent. The polar solvent may especially be chosen from the group consisting of C 1 to C 4 alcohols, acetonitrile, dimethyl sulfoxide and mixtures thereof. According to one embodiment, the total elimination of the surfactant is carried out by repeated washing with a polar solvent.

Typically, the washing is carried out at a temperature of between 20 ^° C. and 60 ^° C.

Partial removal of the surfactant can also be achieved by a single wash with a polar solvent. This polar solvent is preferably selected from the group consisting of dioxane, C5 to C10 alcohols and mixtures thereof. According to a preferred embodiment, the solvent used for the partial and total elimination is identical, the total elimination being obtained by successive washings.

In step e) of the process, the oxide is allowed to react with a second functionalized agent capable of forming a covalent bond with the OH groups released in the previous step.

This step is performed analogously to step c), adapting, if necessary, the conditions to the nature of the functionalized agent selected.

Step f) repeats steps d) and e) for each additional functionality with an appropriate functionalized agent.

If necessary, step g) is performed to ensure complete removal of the remaining surfactant, as described above.

Finally, step h) consists in recovering the multifunctionalized mesostructured porous oxide obtained from the reaction mixture by separation techniques known per se.

The introduced functions can then optionally be modified chemically and selectively while keeping the initial uniform distribution, thus offering a great flexibility of choice in the desired properties according to the intended applications. The described method has the following main advantages:

- a simple implementation;

- soft conditions;

- its speed and low cost;

- the absence of any need for special facilities; It allows access to multi-functional materials with spatial control with a variety of feature combinations, offering the ability to create a customized product. According to another aspect, the invention therefore relates to a multifunctionalized mesostructured porous oxide obtainable by the method described above.

According to a last aspect, the invention relates to the use of a multifunctionalized mesostructured porous oxide as described for selective adsorption by molecular recognition, multifunctional catalysis, selective separation, chromatography, combinatorial chemistry or the remediation of metals.

The invention will be described in more detail by means of the following examples and by means of the appended drawings which show:

Fig. 1: an X-ray diffractogram of solids prepared according to the example: (a) 1; (b) 7; (c) 8;

Fig. 2: an IR spectrum of solids prepared according to Examples 1, 2 and 3; Fig. 3: a spectrum. IR solids prepared according to Examples 1, 7 and 8; Fig. 4: an X-ray diffractogram of solids prepared according to the example: (a) 4; (b) 9; (c) 10;

Fig. 5: an IR spectrum of solids prepared according to example 4, 5 and 6; Fig. 6: an IR spectrum of solids prepared according to example 4, 9 and 10;

Fig. 7: a nitrogen adsorption and desorption isotherm of the solid prepared according to Example 3;

Fig. 8: a nitrogen adsorption and desorption isotherm of the solid prepared according to Example 6;

Fig. 9: a CP-MAS ¹³ C NMR of the solid prepared according to Example 6; Fig. 10: a CP-MAS ²⁹ Si NMR of the solid prepared according to Example 6; Fig. 11: a CP-MAS ¹³ C NMR of the solid prepared according to Example 8;

Fig. 12: a CP-MAS ²⁹ Si NMR of the solid prepared according to Example 8; Fig. 13: a CP-MAS ¹³ C NMR of the solid prepared according to Example 10; Fig. 14: a CP-MAS ²⁹ Si NMR of the solid prepared according to Example 10;

Fig. 15: an X-ray diffractogram of the solid prepared according to the example: (a) 4; (b) 9; (c) 10; (d) 11; Fig. 16: a CP-MAS ¹³ C NMR of the solid prepared according to Example 11; and

Fig. 17: a CP-MAS ²⁹ Si NMR of the solid prepared according to Example 11.

EXAMPLES EXAMPLE 1 Preparation of a Mesostructured Porous Silica

This example describes the preparation of a SBA-3 type silica with a 2D hexagonal structure (honeycomb structure) according to the literature (Huo et al., Chem Mater 1994, 6, 1176) from a gel of the following molar composition: tetraethylorthosilicate (TEOS) 1, 00

H ₂ O 130

HCl 9.2 cetyltrimethylammonium bromide (CTAB) 0.12

The gel was prepared on the basis of a scale from 1, 5-10 ^'2 molar silicon.

In a suitable container, the cetyltrimethylammonium bromide is dissolved in water and 37% hydrochloric acid at 40 ^° C. It is allowed to cool to 25 ° C., then the tetraethyl orthosilicate is added dropwise over a period of five hours. at ten minutes, with stirring. The crystal clear solution trouble immediately. The polycondensation reaction is then continued for three hours at 25 ° C., with stirring.

The powder obtained is then filtered, washed with distilled water and dried in air. The yield of the reaction, based on half of the mass of silica obtained relative to the mass of TEOS introduced, varies between 60 and 70%.

The solids obtained are denoted silica R1 and silica R2. They were characterized by X-ray diffraction (Figure 1) and infrared spectroscopy (Figures 2 and 3). The diffractograms of the two silicas are characterized by the presence of three peaks, between 1 and 10 ° in scale 2Θ, respectively at 35.6, 20.8 and 18.1 Λ, characteristics of mesophases with hexagonal structure.

The infrared absorption spectrum of the two solids contains the characteristic bands of silica (υ _a si-o ~ 900 and 1300 cm ^-1 , ε _S io ~ 750 and 850 cm ^-1 ; δ _{a 0} -sι-o ~ 400 and 650 cm ^-1 ) and those typical of CTAB (υ _C -H ~ 2900 and 3100 cm ^-1 , δ _C -H ~ 1400 and 1550 cm ^-1 ).

The CTAB that was not incorporated in the pores of the material during the synthesis is quantitatively assayed by potassium dichromate precipitation, carried out as follows.

The results obtained are collated in Table 1. After reaction, the aqueous phases resulting from the reaction and successive washes are combined and concentrated if necessary. K ₂ Cr ₂ O ₇ is then added in excess. A precipitate is formed immediately; it is cetyltrimethylammonium dichromate (CTAB) ₂ Cr ₂ O ₇ . The reaction is stirred for two hours at room temperature. The solid is then recovered by filtration, dried in air and weighed precisely. The weighed mass allows us to go back to the cetyltrimethylammonium mass which has not been incorporated into the pores of the oxide formed. EXAMPLE 2

Foπctioπnalisatioπ of mesostructured porous silica with TMSCI

In a suitable container, a silica (0.702 g) obtained according to Example 1 is suspended in toluene (15 ml) previously dried over P ₂ O ₅ . Via a syringe, 3 ml of trimethylchlorosilane (TIVISCI, 0.024 mol) are then introduced dropwise into the suspension. The reaction mixture is heated at 55 ° C for a period of 3 hours, with stirring and under a nitrogen atmosphere. After reaction, the solid is filtered on a frit maintained under nitrogen, washed

3% with 10 ml of toluene and dried at 25 ° C. under dynamic vacuum (10 ^-2 mm)

Hg).

The solid thus functionalized, noted R1-TMS silica is characterized by X-ray diffraction and infrared spectroscopy. The X-ray diffractogram indicates that the hexagonal structure of the material is preserved during the functionalization step without a significant change in the intensity of the peak d (100) to 35 Λ. The infrared spectrum (FIG. 2), in addition to the characteristic bands of silica and CTAB, has new bands at 2960 and 852 cm ^-1 , attributed to the trimethylsilane moiety. The residue is taken up in water and the CTAB, which was optionally extracted during this functionalization step, is quantitatively determined by precipitation with potassium dichromate as described in Example 1. The results obtained are shown in Table 1. EXAMPLE 3

Removal of the surfactant from a functionalized mesostructured porous silica

In a suitable container, a trimethylchlorosilane functionalized silica (R1-TMS silica) (0.652 g) prepared according to Example 2 is suspended in absolute ethanol (25 ml). The reaction mixture is heated at 65 ° C for one hour, with stirring and under a nitrogen atmosphere.

The solid is then filtered and resuspended in 25 ml of fresh ethanol. Three extraction cycles are performed to remove the surfactant and release the porosity quantitatively.

After drying at 25 ° C. under dynamic vacuum (10 ^-2 mm Hg), the solid obtained, denoted silica R 1 -TMS-E, is characterized by X-ray diffraction, infrared spectroscopy, carbon-13 nuclear magnetic resonance spectroscopy and silicon-29, by isothermal adsorption / desorption of nitrogen and by elemental analysis.

The X-ray diffractogram indicates that the hexagonal structure of the material is preserved during the CTAB extraction step with an increase in peak intensity d (100) to 35 Λ suggesting a release of porosity. The infrared spectrum (FIG. 2) shows that the extraction was complete, in particular by the total disappearance of the typical CTAB vibration bands in the spectral region 2900-2800 cm- ¹ Nitrogen sorption (adsorption and desorption) measurements (Figure 7) show typical Type IV isotherm of mesostructured materials with a surface area of 1000 m ² / g and an average pore size of 2.2 nm.

Elemental analysis (C% 11.06, H% 3.48, N% <0.10 (residual mass at 1000 ^° C., 82.22%)) indicates that it was introduced during the step of functionalization about 3-10 ^'3 moles of TMS fragment per gram of silica or 3.7 10 ^{' 3} moles of TMS fragment per gram of dry silica.

The ethanol solutions from the three cycles are collected and then evaporated. The residue is taken up in water and the CTAB which was removed during this extraction step is quantified by precipitation with potassium dichromate as described in Example 1. The results obtained are summarized in Table 1.

EXAMPLE 4 Preparation of a Mesostructured Porous Silica

This example describes a process for preparing a mesostructured porous silica different from Example 1, in particular in that it is carried out in the presence of a cosolvent.

An SBA-3 type silica having a 2D hexagonal structure (honeycomb structure) was prepared from a gel of the following molar composition: tetraethylorthosilicate (TEOS) 1.00

CH ₃ CN 4.3

H ₂ O 120 HCl 9.2 cetyltrimethylammonium bromide (CTAB) 0.12

The gel was prepared on the basis. a scale of 1, 5-10 ^'2 molar silicon.

In a suitable container, the cetyltrimethylammonium bromide is dissolved in water and the hydrochloric acid at 40 ^° C. Half of the amount, the acetonitrile is then added to this solution. We let Cool to 25 ° C, then add the tetraethylorthosilicate solution in the acetonitrile residue dropwise over a period of five to ten minutes with stirring. The clear solution becomes cloudy immediately. The polycondensation reaction is then continued for three hours at 25 ° C., with stirring.

The solids obtained were analyzed by X-ray diffraction (FIG. 4) and by infrared spectroscopy (FIGS. 5 and 6). The diffractograms of the two silicas are characterized by the presence of two peaks, between 1 and 10 ° in scale 2Θ, respectively at 34.5 and 20 Â characteristics of a hexagonal structure. '

The infrared spectrum of both solids contain the characteristic bands of silica (υ _has sι-o ~ 900 and 1300 cm ^"1; υ _s sι-o ~ 750 and 850 ^cm"1; δ _a o-si-o ~ 400 and 650 cm ^-1 ) and CTAB (υ _C -H ~ 2900 and 3100 cm ^-1 , δ _C -H-1400 and 1550 cm ^-1 ).

The CTAB that was not incorporated in the pores of the material during the synthesis is quantitatively assayed by potassium dichromate precipitation as described in Example 1. The results obtained are collated in Table 1.

EXAMPLE 5

Functionalization of a mesostructured porous silica with TMSCI In a suitable container, a silica (Al) (0.710 g) obtained according to Example 4 is suspended in toluene (15 ml) previously dried over P ₂ O ₅ . Via a syringe, 3 ml of trimethylchlorosilane (TIVISCI ₁ 0.024 moles) are then introduced dropwise into the suspension. The reaction mixture is heated at 55 ° C for a period of 3 hours, with stirring and under a nitrogen atmosphere.

After reaction, the solid is filtered on a frit kept under nitrogen, washed 3 times with 10 ml of toluene and dried at 25 ° C. under dynamic vacuum (10 ^-2 mm).

Hg).

The solid thus functionalized, noted Silica A1-TMS is characterized by X-ray diffraction and infrared spectroscopy. The X-ray diffractogram indicates that the hexagonal structure of the material is preserved during the functionalization step without any significant change in the intensity of the peak d (100) to 34.5 A. The infrared spectrum (FIG. 5) presents, for its part, in addition to the characteristic bands of silica and CTAB, new bands at 2960 and 852 cm ^-1 , attributed to the trimethylsilane moiety.

The toluene stock solution and the washing solutions are combined and the toluene is evaporated. The residue is taken up in water and the CTAB optionally extracted during this functionalization step is quantitatively determined by precipitation with potassium dichromate as described in Example 1. The results obtained are collated in Table 1.

EXAMPLE 6

Removal of the surfactant from a functionalized mesostructured porous silica

In a suitable container, a silica functionalized with trimethylchlorosilane (Silica A1-TMS) (0.568 g) prepared according to Example 5 is suspended in absolute ethanol (25 ml). The reaction mixture is heated at 65 ° C for one hour, with stirring and under a nitrogen atmosphere. The solid is then filtered and resuspended in 25 ml of fresh ethanol. Three extraction cycles are performed to remove the surfactant and release the porosity quantitatively.

After drying at 25 ^° C. under dynamic vacuum (10 ^{~ 2} mmHg), the solid obtained (silica A1 -TMS-E) is characterized by X-ray diffraction, by infrared spectroscopy, by carbon-13 nuclear magnetic resonance and by silicon-29, by isothermal adsorption / desorption of nitrogen and by elemental analysis.

The X-ray diffractogram indicates that the hexagonal structure of the material is preserved during the CTAB extraction step. An increase in peak intensity d (100) to 34.5 Λ suggests a release of porosity. The infrared spectrum (FIG. 5) shows that the extraction was complete, in particular by the total disappearance of the typical CTAB vibration bands in the spectral region 2900-2800 cm- ^{1, the} nitrogen sorption (adsorption and desorption) measurements. (Figure 8) shows a typical Type IV isotherm of mesostructured materials with a specific surface area of

1090 m ² / g and an average pore size of 2.5 nm. The solid NMR spectrum of carbon (Figure 9) is characterized by the presence of a 0.5 ppm carbon-attributed resonance of the (CH ₃ ) ₃ Si- moiety suggesting that the integrity of this fragment was maintained during extraction. The NMR spectrum of silicon makes it possible to evaluate, for its part, the nature of the bond with the surface of the silica. It can be seen in FIG. 10 the presence of a 13 ppm peak typical of a primary silicon atom containing an Si-O-Si bond and in the -90 / -110 ppm spectral region the resonances of the silica (Q ² , Q ³ and Q ⁴ ) corresponding to more or less condensed quaternary silicon atoms.

Elemental analysis (C% 6.73, H% 2.51, N% <0.10 (residual mass at 1000 ^° C., 83.20%)) indicates that it was introduced during the step of functionalization about 1, 9 10 ^"3 moles of TMS fragment per gram of silica 2.2 ^{10" 3} moles of TMS fragment per gram of dry silica.

EXAMPLE 7 Functionalization of a mesostructured porous silica with

VDMSCI

In a suitable container, a silica (0.866 g) prepared according to Example 1 is suspended in toluene (15 ml) previously dried over P ₂ O ₅ . Via a syringe, 4.0 ml of vinyldimethylchlorosilane (VDMSCI, 0.029 mol) are then introduced dropwise into the suspension. The reaction mixture is heated at 55 ° C for a period of 3 hours, with stirring and under a nitrogen atmosphere.

After reaction, the solid is filtered on a frit maintained under nitrogen, washed 3 times with 10 ml of toluene and dried at 25 ° C under dynamic vacuum (10 ² mm / Hg).

The solid thus functionalized, denoted silica R2-VDMS, is characterized by X-ray diffraction and infrared spectroscopy. The diffractogranm X (Figure 1) indicates that the hexagonal structure of the material is preserved during the functionalization step without significant change in the intensity of the peak d (100) to 35 Λ, the infrared spectrum (Figure 3) has, as for in addition to the characteristic bands of silica and CTAB, new bands at 3070, 2960, 1419 and 847 cm ^-1 , attributed to the vinyldimethylsilane fragment. The toluene stock solution and the washing solutions are combined and the toluene is evaporated. The residue is taken up in water and the

CTAB which would have been extracted during this functionalization step is quantified quantitatively by potassium dichromate precipitation as described in Example 1. The results are summarized in Table 1.

EXAMPLE 8

Removal of the surfactant from a functionalized mesostructured porous silica In a suitable container, a silica functionalized with vinyldimethylchlorosilane (silica R2-VDMS) (0.905 g) prepared according to Example 7 is suspended in absolute ethanol (25 ml ). The reaction mixture is heated at 65 ° C for one hour, with stirring and under a nitrogen atmosphere. The solid is then filtered and resuspended in 25 ml of fresh ethanol. Three extraction cycles are performed to remove the surfactant and release the porosity quantitatively.

After drying at 25 ^° C. under dynamic vacuum (10 ^-2 mm / Hg), the solid obtained, denoted silica R2-VDMS-E, is characterized by X-ray diffraction, infrared spectroscopy, carbon-13 nuclear magnetic resonance and silicon-29 and by elemental analysis.

The X-ray diffractogram (Figure 1) indicates that the hexagonal structure of the material was maintained during the CTAB extraction step with an increase in peak intensity d (100) to 35 A suggesting a release of porosity. The infrared spectrum (FIG. 3) shows that the extraction was complete, in particular by the total disappearance of the typical CTAB vibration bands in the spectral region 2900-2800 cm ^-1, we also observe the bands assigned to the 3070 vinyldimethylsilane fragment. 2960, 1419 and 847 ^cm 1. The solid carbon NMR spectrum (Figure 11) is characterized by the presence of a resonance at -5.5 ppm attributed to two fragment methyl carbons (CHs) ₂ Si-CH = CH ₂ and by the presence of two other resonances at 127.7 and 133.8 ppm typical of the vinyl group ((CH ₂ ) ₂ Si-CH = CH ₂ ). This indicates that the integrity of this fragment was maintained during extraction. The NMR spectrum of silicon makes it possible to evaluate, for its part, the nature of the bond with the surface of the silica. FIG. 12 shows the presence of a peak at 0.7 ppm typical of a primary silicon atom containing an Si-O-Si bond and bearing a vinyl group and in the spectral region -90 / -110 ppm the resonances of silica (Q ² , Q ³ and Q ⁴ ) corresponding to more or less condensed quaternary silicon atoms.

Elemental analysis (C% 9.78, H% 2.92, N% <0.10 (residual mass at 1000 ° C: 80.65%)) indicates that it was introduced during the functionalization step about 2-10 ^"3 moles of VDMS fragment per gram of silica is 2,5 ^{10 -3} moles of VDMS fragment per gram of dry silica.

EXAMPLE 9

Functionalization of a Mesostructured Porous Silica with CNPDMSCI

In a suitable container, a silica (0.990 g) prepared according to Example 2 is suspended in toluene (15 ml) previously dried over P ₂ Os. Via a syringe, 5.4 ml of cyanopropyldimethylchlorosilane (CNPDMSCI, 0.033 moles) are then added dropwise to the suspension. The reaction mixture is heated at 55 ° C for a period of 3 hours, with stirring and under a nitrogen atmosphere.

After reaction, the solid is filtered on a frit maintained under nitrogen, washed 3 times with 10 ml of toluene and dried at 25 ° C. under dynamic vacuum.

(10 ^"2 mm / Hg) The solid thus functionalized, noted Silica A2-CNPDMS is characterized by X-ray diffraction and infrared spectroscopy.The diffractogram X (Figure 4) indicates that the hexagonal structure of the material was maintained during the functionalization step without significant change in peak intensity d (100) to 34.5 A. The infrared spectrum (FIG.

6) presents, in turn, in addition to characteristic bands of silica and

CTAB of new bands at 2972, 2262, 1435 and 843 cm ^-1 assigned to the cyanopropyldimethylsilane moiety.

The toluene stock solution and the washing solutions are combined and the toluene is evaporated. The residue is taken up in water and the

CTAB that would have been extracted during this functionalization step is quantified by precipitation with potassium dichromate as described in Example 1. The results are summarized in Table 1. ^•

EXAMPLE 10

Removal of the surfactant from a functionalized mesostructured porous silica

In a suitable container, a cyanopropyldimethylchlorosilane functionalized silica (A2-CNPDMS) (0.825 g) prepared according to Example 9) is suspended in absolute ethanol (25 ml). The reaction mixture is heated at 65 ° C for one hour, with stirring and under a nitrogen atmosphere. The solid is then filtered and resuspended in 25 ml of fresh ethanol. Three extraction cycles are performed to remove the surfactant and release the porosity quantitatively.

After drying at 25 ° C. under dynamic vacuum (10 ^-2 mm Hg), the solid obtained, noted as silica A2-CNPDMS-E, is characterized by X-ray diffraction, by infrared spectroscopy, by carbon-13 nuclear magnetic resonance and by silicon-29 and by elemental analysis.

The X-ray diffractogram (Fig. 4) indicates that the hexagonal structure of the material is conserved during the CTAB extraction step with an increase in peak intensity d (100) at 35Å suggesting a release of porosity. The infrared spectrum (FIG. 6) shows that the extraction was complete in particular by the total disappearance of the typical CTAB vibration bands in the spectral region 2900-2800 cm ^-1 . The bands assigned to the cyanopropyldimethylsilane fragment at 2972, 2262, 1435 and 843 cm- ¹ are also observed.

The solid NMR spectrum of the carbon (FIG. 13) is characterized by the presence of a resonance at -4.5 ppm attributed to the two methyl carbons of the (CH ₃ ) Si-CH ₂ CH ₂ CH ₂ CN fragment, from two resonances to 13.1 and 15.9 ppm corresponding to the three methylene carbons of the propyl chain, (CHs) ₂ Si-CH ₂ CH ₂ CH ₂ CN, and a resonance at 115.4 ppm typical of the nitrile carbon, (CHs) ₂ Si-CH ₂ CH ₂ CH ₂ CN This indicates that the integrity of this fragment was maintained during the extraction process.The NMR spectrum of silicon allows us to evaluate, for its part, the nature of the bond with the surface of silica, there is shown in FIG. 14 the presence of a peak at 12.3 ppm typical of a primary silicon atom containing an Si-O-Si bond and carrying a cyanopropyl group and in the spectral region -90 / - 110 ppm the resonances of the silica (Q ² , Q ³ and Q ⁴ ) corresponding to more or less condensed quaternary silicon atoms. Elemental analysis (C% 13.95, H% 3.21, N% 2.58 (residual mass at 1000 ^° C.: 76.90%)) indicates that during the functionalization step about 1 84 10 ^"3 moles CNPDMS fragment per gram of silica is ^{2.4-10" 3} mol CNPDMS fragment per gram of dry silica.

EXAMPLE 11

Preparation of a bifunctional mesostructured silica

In a suitable container, a silica functionalized with cyanopropyldimethylchlorosilane whose surfactant was removed, according to Example 10) (silica A2-CNPDMS-E) (1.0 g) is suspended in toluene (15 ml) previously dried on P ₂ O ₅ . Using a syringe, 4.0 ml of chloropropyldimethylchlorosilane (CIPDMSCI, 0.024 mol) are then introduced dropwise into the suspension. The reaction mixture is heated at 55 ° C for a period of 3 hours, with stirring and under a nitrogen atmosphere.

After reaction, the solid is filtered on a sintered maintained under nitrogen, washed 3 times with 10 ml of toluene and dried at 25 ° C under dynamic vacuum (10 ^-2 mm / Hg). The solid obtained, denoted silica A2-CNPDMS-E-CIPDMS, is characterized by X-ray diffraction, by carbon-13 nuclear magnetic resonance and by elemental analysis. The diffractogram X (FIG. 15) indicates that the hexagonal structure of the material is preserved during the second functionalization with a slight decrease in the intensity of the peak d (100) at 35 Λ. The resonances typical of the (CHa) ₂ Si-CH ₂ CH ₂ CH ₂ CN fragment at -4.5, 13.1, 15.9 and 115.4 ppm are found in the solid NMR spectrum of carbon (FIG. attribution has been given in detail in Example 10). We also observe two new resonances at 22.9 and 43.8 ppm corresponding to the methylene carbons of the propyl chain of the (CHa) ₂ Si-CH ₂ CH ₂ CH ₂ Cl fragment, located respectively in β and in α of chlorine. The other signals corresponding to the other carbons of this fragment are masked by the signals of the CNPDMS fragment.

These results show that the material obtained was functionalized by the two types of functional grouping. The NMR spectrum of silicon makes it possible to evaluate, for its part, the nature of the bond with the surface of the silica. FIG. 14 shows the presence of a 12.5 ppm peak typical of a primary silicon atom containing an Si-O-Si bond and in the -90 / -110 ppm spectral region the resonances of the silica ( Q ² , Q ³ and Q ⁴ ) corresponding to more or less condensed quaternary silicon atoms. Elemental analysis (C% 15.33, H% 3.44, N% 2.42, Cl 1, 15 (residual mass at 1000 ⁰ C: 75.31%)) indicates that the two sequential steps about 2.3-10 ^"3 moles of CNPDMS fragment per gram of dry silica (based on the percentage of nitrogen) and 4.30-10 ^{" 4} moles of CIPDMS per gram of dry silica (based on the percentage of chlorine) is a molar ratio between the two CNPDMS / CIPDMS functional groups of 5.3. - Table 1

Claims

A process for producing a multifunctionalized mesostructured porous oxide comprising the steps of: a) acid polycondensing an oxide precursor in a micellar solution of ionic surfactant leading by selfassembly to a mesostructured porous oxide containing surfactant micelles; b) separating the oxide formed from the reaction mixture; c) allowing the oxide containing surfactant micelles to react with a first functionalized agent capable of forming a covalent bond with the accessible OH groups of the oxide; d) at least partially removing the surfactant from the functionalized oxide; e) allowing the oxide to react with a second functionalized agent capable of forming a covalent bond with the groups

OH released from the oxide; f) repeating steps d) and e) for each additional functionality with an appropriate functionalized agent; (g) if necessary, remove the remaining surfactant; and h) recovering the multifunctionalized mesostructured porous oxide obtained.

The method of claim 1, wherein the precursor is a precursor of a non-metallic oxide.

3. The process of claim 2 wherein the oxide is silica.

4. Method according to one of claims 1 to 3, wherein the micellar solution in step a) comprises an organic solvent as cosolvent.

The process of claim 4, wherein the organic cosolvent is polar.

The process according to claim 5, wherein the cosolvent is selected from the group consisting of ethanol, ethylene glycol, tetraglyme, glycerol, tetrahydrofuran, ether, acetonitrile, dimethylformamide, N methylformamide, methylformamide, ethyl acetate, dimethylsulfoxide and mixtures thereof.

7. Method according to one of claims 1 to 6, wherein the molar ratio between the oxide precursor and the micellar solution in step a) is chosen so as to form a mesostructured solid in a hexagonal or cubic symmetry.

8. Method according to one of claims 1 to 7, wherein the surfactant is selected from the group consisting of quaternary ammonium salts bearing one or two aliphatic groups having 6 to 24 carbon atoms, the quaternary phosphonium salts carrying one or two aliphatic groups having 6 to 24 carbon atoms, the carboxylate salts having 6 to 24 carbon atoms, and the sulphonate salts having 6 to 24 carbon atoms.

The process of claim 8, wherein the aliphatic group is a straight alkyl group having 6 to 24 carbon atoms.

10. Method according to one of claims 1 to 9, wherein step a) is carried out at room temperature.

11. Process according to one of claims 1 to 10, in which step c) is carried out with an apolar aprotic solvent selected from the group consisting of petroleum ethers, optionally alkylated aromatic hydrocarbons, straight alkanes and alkenes, branched or cyclic compounds having 4 to 18 carbon atoms, as well as mixtures thereof, and preferably toluene.

12. Method according to one of claims 1 to 11, wherein the functionalized agent (s) are organosilyl compounds.

13. Method according to one of claims 1 to 12, wherein the functionalized agent comprises a chiral function.

14. Method according to one of claims 1 to 13, wherein the functionalized agent comprises a function capable of acting as a ligand.

15. Method according to one of claims 12 to 14, wherein the organosilyl compound is an organochlorosilane of formula:

wherein _Ri,. R ₂ and R 3 are independently of each other selected from the group consisting of straight, branched and cyclic alkyl and alkenyl groups and aryl groups, optionally substituted by one or more functions alcohol, amine, imine, halide, nitro, thiol, phosphino cyano, alkoxy, carboxy, ester and / or acetylacetonato.

16. The method of claim 15, characterized in that R ₃ is a chlorine atom.

17. The method of claim 16, characterized in that R ₂ is a chlorine atom.

18. Method according to one of claims 15 to 17, characterized in that the organochlorosilane is selected from the group consisting of trimethylchlorosilane, phenyldimethylchlorosilene, propyl-dimethylchlorosilane,. ethyldimethylchlorosilane, vinyldimethylchlorosilane, octyldimethylchlorosilane, dodecyldimethylchlorosilane, diphenylmethylchiorosilane, chloromethyldimethylchlorosilane, 2- (3-cyclohexenyl) ethyldimethylchlorosilane, 3-chloropropyldimethylchlorosilane, (3-cyanopropyl) dimethyl- chlorosilane, the (methoxy) dimethylchlorosilane, (N ₁ N-dimethylamino) dimethylchlorosilane, (dichloro-methyl) dimethylchlorosilane, 5-hexenyldimethylchlorosilane, 3-

(Methacryloxypropyl) dimethylchlorosilane.

19. Method according to one of claims 1 to 18, wherein the functionalized agent is an organosiloxane of general formula:

wherein R ₁ , R ₂ , R 3 are independently of each other as defined in claim 15.

20. The method of claim 1 to 19, wherein the total removal of the surfactant is carried out with a polar solvent.

21. The method of claim 20, wherein the polar solvent is selected from the group consisting of C1 to C4 alcohols, acetonitrile, dimethylsulfoxide and mixtures thereof.

22. The method of claim 1 to 21, wherein the total removal of the surfactant is carried out by repeated washing with a polar solvent.

23. The method of claim 1 to 21, wherein the partial removal of the surfactant is carried out by a single wash with a polar solvent.

24. The method of claim 23, characterized in that the polar solvent is selected from the group consisting of dioxane, C5 to C10 alcohols and mixtures thereof.

25. A multifunctionalized mesostructured porous oxide obtainable by the method according to one of claims 1 to 24.

26. Oxide according to claim 25, characterized in that it is a silica.

27. Use of a multifunctionalized mesostructured porous oxide according to claim 25 or 26 for selective adsorption by molecular recognition, multifunctional catalysis, selective separation, chromatography, combinatorial chemistry or metal remediation.