WO2000044670A1

WO2000044670A1 - Method for preparing mcm-48-type mesoporous titanosilicates and their use as catalysts in selective oxidation reactions

Info

Publication number: WO2000044670A1
Application number: PCT/ES2000/000030
Authority: WO
Inventors: Avelino Corma Canos; Marcelo Eduardo Domine; Maria Lourdes PEÑA LOPEZ; Fernando Rey Garcia
Original assignee: Consejo Superior De Investigaciones Cientificas; Universidad Politecnica De Valencia
Priority date: 1999-01-29
Filing date: 2000-01-27
Publication date: 2000-08-03
Also published as: ES2159224A1; ES2159224B1

Abstract

The invention relates to a method for preparing MCM-48-type mesoporous titanosilicates which may or may not have organic groups on their surfaces. Titanium may be incorporated through direct synthesis by adding titanium precursor to the synthesis gel or by anchoring titanium compounds on a silica surface. Said compounds are used as catalysts in selective oxidation processes of organic compounds with organic or inorganic peroxides.

Description

TITLE

Process for the preparation of mesoporous titanosilicates type MCM-48, and their use as a catalyst in selective oxidation reactions.

FIELD OF THE TECHNIQUE

Catalytic materials

BACKGROUND

Recently it has been revealed that silicotitates with MFT structures,

MEL and BEA are active catalysts in selective epoxidation reactions of olefins, as well as in other oxidation reactions of organic compounds such as alloys, sulfides, phenol, etc. However, these materials have serious diffusional limitations when trying to process bulky reagents. This limitation has been remedied through the use of mesoporous solids with structures type MCM-41 containing Ti in its composition taking advantage of the fact that these materials can be prepared with channel systems with diameters between 15 to 300 Á. However, these mesoporous catalysts have a lower activity and intrinsic selectivity in olefin epoxidation reactions than their zeolitic analogues, probably due to the different adsorption properties and the different coordination environment of the active Ti centers.

(IV).

It has been observed that the modification of the adsorption properties after a silylation process improves both the conversion and the selectivity to the desired products in olefin epoxidation reactions. If the catalytic properties of Ti-MCM-41 materials have been extensively studied, the same cannot be said of other materials with mesoporous structures that contain Ti in their structure, as is the case of Ti-MCM-48 type solids. These materials have pore systems with openings analogous to those found in MCM-41, but unlike this, the pore systems have a three-way structure, which facilitates the diffusion of reagents. In addition, these materials, for the same pore diameter as the MCM-41, have a larger specific surface. Therefore, they are excellent candidates for use in selective oxidation processes. BRIEF DESCRIPTION OF THE INVENTION

This invention claims the use of mesoporous catalysts type MCM-48 based on silica containing Ti in its composition, which may or may not have organic groups anchored on its surface, in processes of selective oxidation of olefins with organic hydroperoxides such as terbutylhydroperoxide or hydroperoxide of eumeno, without being these limiting examples.

This reaction is carried out by contacting a reactive mixture containing olefin and organic or inorganic hydroperoxide with the MCM-48 type mesoporous solid catalyst at a temperature between 10 and 200 ° C with constant stirring during reaction times that can vary between 5 minutes to 24 hours depending on the catalyst and the reaction conditions employed. Likewise, this reaction can be carried out in a continuous reactor in which the reactive mixture, containing olefin and hydroperoxide, is passed through a catalytic bed at a temperature between 10 and 400 ° C, using special speeds between 10 and 0.01 h ^"1 .

The hydrophilicity-hydrophobicity properties of the catalyst can be modified by anchoring organosilicon compounds on the surface of the mesoporous solid type MCM-48 and adapting these to the specific characteristics of the reagents. The incorporation of Titanium in the MCM-48 type mesoporous catalyst can be carried out by direct synthesis, in which a titanium precursor is added to the synthesis gel, or by anchoring titanium compounds on a silica surface that give rise to species of Ti isolated after a calcination process. Finally, in the case of using organic structure-directing compounds during the synthesis of the MCM-48 type mesoporous material, the removal of the organic species found inside the pores of the MCM-48 type mesoporous material can be carried out. by calcination of the catalyst or by chemical extraction thereof.

In this way, highly active and selective catalysts have been obtained in processes of selective oxidation of definas. In the present invention a process is described by which oxidation products of olefins, mainly epoxides, aldehydes or ketones, with high conversions and selectivities are obtained. This method is based on the use of silica-based mesoporous solid catalysts type MCM-48 containing titanium in its composition.

The catalyst before removing the occluded organic in its pores has the following molar composition:

SiO ₂ : x TiO ₂ : n S where x can vary between 0.0001 and 0.5, S can be an organic compound, such as a cationic, anionic or neutral surfactant. Cationic surfactants respond to the formula R ₁ R ₂ R ₃ RQ ⁺ where Q is nitrogen or phosphorus and where at least one of the substituents Ri, R ₂ , R ₃ or R 'is an aryl or alkyl group containing more than 6 atoms carbon and less than 36, and each of the remaining groups R1, R _2, R ₃ ot is a hydrogen or an alkyl or aryl group with less than five carbons. Also included within the cationic surfactants that can be incorporated into the gel composition are called gemstone surfactants,

or RιR ₂ R ₃ Q (R ₄ R ₅ QR6QR4R ₅ ) Qn ιR2R3 where Q is a nitrogen or phosphorus and at least one of the R Rδ substituents is an alkyl or aryl group with more than six carbon atoms and less than 36, and each of the remaining Ri-Re groups are hydrogens or alkyl or aryl groups with memos of five carbon atoms or mixtures thereof. In these cases two of the groups R_, R ₂ , R ₃ or Rt can be interconnected giving rise to cyclized compounds. Cationic surfactants are introduced into the synthesis gel composition in the form of hydroxide, halide, nitrate, sulfate, carbonate or silicate or mixtures thereof. Non-limiting examples of them are cetyltrimethylammonium, dodecyltrimethylammonium, cetylpyridinium, cetyltrimethylphosphonium, etc. S may also refer to a neutral surfactant, in which case they respond to the formula R1R2R3Q where Q is nitrogen or phosphorus and where at least one of the substituents Ri, R ₂ , or R ₃ is an aryl or alkyl group containing more than 6 atoms carbon and less than 36, and each of the remaining Ri, R2 or R _{3 groups} is a hydrogen or an alkyl or aryl group with less than five carbons, non-limiting examples being dodecylamine, cetylamine and cetylpyridine. Compounds that respond to the nR-EO formula consisting of an alkyl polyethylene oxides, alkyl aryl polyethylene oxides and alkyl polypropylene and alkylene copolymers may also act as neutral surfactants, examples not being limiting commercial surfactants called Tergitol 15-S-9, Triton X-114, Igepal RC-760, Pluronic 64 L, Tetronic and Sorbitan. Esters derived from fatty acids obtained by reaction with short chain alcohols, sugars, amino acids, amines and polymers or copolymers derived from polypropylene, polyethylene, polyacrylamide or polyvinyl alcohol may also be included in the formulation, non-limiting examples are lisolecithin, lecithin, dodecyl ether of pentaoxyethylene, phosphatyldilauryldiethanolamine, digalactose diglyceride and monogalactose diglyceride. The surfactant can also be an anionic surfactant that responds to the formula RQ ^" where R is an aryl or alkyl group containing more than 6 carbon atoms and less than 36, and Q is a carboxylic, phosphate or sulfate group, non-limiting examples being Dodecyl sulfate, stearic acid, Aerosol OT and phospholipids such as phosphatyl choline and diethanolamine phosphatyl, and n can vary between 0 and 0.5.

The synthesis of these MCM-48 type mesoporous catalysts is carried out by preparing a gel of molar composition: SiO ₂ : x TiO ₂ : n S: m TAAOH: x H ₂ O where x can take values between 0.0001 and 0.5, S can be a cationic, anionic or neutral surfactant. Cationic surfactants respond to the formula R ₁ R2R3R Q where Q is nitrogen or phosphorus and where at least one of the substituents Ri, R2, R ₃ or Rt is an aryl or alkyl group containing more than 6 carbon atoms and less than 36 , and each of the remaining groups Ri, R2, R? or R _t is a hydrogen or an alkyl or aryl group with less than five carbons. Also included within the cationic surfactants that can be incorporated into the gel composition are called gemstone surfactants, R ₁ R ₂ R ₃ QR QRιR2R3 or R ₁ R ₂ R ₃ Q (Tt ₄ R5QR5QR4R5) nQRιR2R3 where Q is a nitrogen or phosphorus and at least one of the substituents R1-R5 is an alkyl or aryl group with more than six carbon atoms and less than 36, and each of the remaining _RΪ- R groups are hydrogens or alkyl or aryl groups with memes of five carbon atoms or mixtures of them. In these cases two of the Ri, R_, R ₃ or R groups can be interconnected giving rise to cyclized compounds. Cationic surfactants are introduced into the synthesis gel composition in the form of hydroxide, halide, nitrate, sulfate, carbonate or silicate or mixtures thereof. Non-limiting examples of them are cetyltrimethylammonium, dodecyltrimethylammonium, cetylpyridinium, cetyltrimethylphosphonium, etc. S may also refer to a neutral surfactant, in which case they respond to the formula R ₁ R2R3Q where Q is nitrogen or phosphorus and where at least one of the substituents Ri, R ₂ , or R3 is an aryl or alkyl group containing more than 6 carbon atoms and less than 36, and each of the remaining Ri, R_ or R _{3 groups} is a hydrogen or an alkyl or aryl group with less than five carbons, non-limiting examples being dodecylamine, cetylamine and cetylpyridine. Compound neutral surfactants that respond to the nR-EO formula consisting of an alkyl polyethylene oxides, alkyl aryl polyethylene oxides and alkyl polypropylene and alkylene ethylene copolymers may also act as non-limiting examples, commercial surfactants termed Tergitol 15 S 9, Triton X-114, Igepal RC-760, Pluronic 64 L, Tetronic and Sorbitan. Esters derived from fatty acids obtained by reaction with short chain alcohols, sugars, amino acids, amines and polymers or copolymers derived from polypropylene, polyethylene, polyacrylamide or polyvinyl alcohol may also be included in the formulation, non-limiting examples being lisolecithin, lecithin, dodecyl ether of pentaoxyethylene, dilauryldiethanolamine phosphatyl, digalactose diglyceride and monogalactose diglyceride. The surfactant can also be an anionic surfactant that respond to the formula RQ ^" where R is an aryl or alkyl group containing more than 6 carbon atoms and less than 36, and Q is a sulfate, carboxylic, phosphate or sulfate group, examples being Non-limiting dodecylsulfate, stearic acid, Aerosol OT and phospholipids such as phosphatylcholine and dietarylamine phosphatyl.n may be varied between 0 and 5. TAAOH refers to a tetraalkylammonium, tetraarylammonium or arylakylammonium hydroxide, ammonium, alkali metal, alkaline earth metals or mixtures of them, m can be varied between 0 and 10.

The synthesis of these materials is carried out by preparing an aqueous, alcoholic solution or water / alcohol mixture containing TAAOH and the surfactant. In some cases, when the surfactant is added in the form of hydroxide, the addition of TAAOH may not be necessary. A source of pure or dissolved silicon is added to the resulting solution with constant stirring and at temperatures between 0 and 90 ° C. Finally, a source of pure titanium or in solution is added to the reaction mixture. As sources of Ti and / or Si oxides, oxyhydroxides, alkoxides, halides or any of its salts, and in general any Ti and / or Si compound capable of being hydrolyzed under the reaction conditions can be used. The resulting mixture is stirred until completely homogeneous for times between 0.1 minutes and 60 hours in order to eliminate part or all of the alcohols that could have been introduced into the synthesis gel.

The resulting mixture is heated between 20 and 200 ° C for a time between 10 minutes and 60 hours. The final solids are separated from the mother liquors, washed with water, alcohol or water-alcohol mixtures and dried.

The organic occluded in the pores of the materials can be removed by calcination at temperatures between 300 and 1100 ° C, or it is extracted by supercritical conditions using alcohol-water mixtures, or any other aqueous mixture capable of presenting a certain character weak acid in supercritical conditions. The occluded organic can also be extracted by treatment with a mixture of one or more mineral or organic acids in a solvent that can be water, alcohol, hydrocarbons or mixtures thereof. As acids, sulfuric acid, nitric acid, hydrochloric acid, perchloric acid, acetic acid, mono, di or trichloroacetic acid, mono, di or trifluoroacetic acid are preferred, these examples being not limiting. This treatment is intended to extract the surfactant or other organic residue that may be occluded within the pores of the catalyst. This treatment is carried out at temperatures between 0 and 250 ° C in one or more successive stages of extraction, although generally two or three stages are usually sufficient to extract all of the organic from the inside of the pores. The duration of this treatment is between 10 minutes and 40 hours depending on the acid or mixture of acids used, the extraction temperature, the solvent and the liquid / solid ratio, the preferred range for the latter being between 5 and 100 gg ^"1 .

These catalysts respond to the chemical formula: SiO ₂ : x TiO ₂ : a H ₂ O where x can vary between 0.00001 and 0.25, preferably between 0.0001 and 0.1 and depends on the degree of hydration of the material and can vary between 0 and 2. These catalysts they have a high specific surface area between 200 and 1500 rn ^ g ^"1 and have an intense band in the UN-vis spectrum centered around 220 nm, indicating the presence of Ti in tetrahedral environments. These catalysts are active and selective in epoxidation reactions of olefins. These materials can also be prepared by anchoring Ti species on the hydroxylated surface of a purely siliceous MCM-48 mesoporous material. In this case, the silicic precursor is prepared analogously to the above, but no reagent containing titanium is included in its preparation. The purely silicic type MCM-48 mesoporous solid is dehydrated and contacted with a titanium compound in gas phase or in organic solution where a catalyst is present, which favors the reaction between the Si-OH groups of the MCM-48 type mesoporous material and the titanium compound, the catalyst being an amine, ammonia or an organic or inorganic hydroxide. Preferred as titanium compounds are: titanium halides, titanium alkoxides, dichlorotitanocene or titanium complexes in which the titanium atom is coordinated by a dionate group such as acetylacetonate, ammonium or sodium hexafluorotitanate and any ionic salt or complex containing titanium in its composition and may be capable of reacting with a Si-OH group under the conditions of preparation of the claimed material. Excess reagents are removed by washing and / or heat treatment in an inert atmosphere, followed by calcination in air under conditions in which organic matter or halogens that may be present in the material are removed.

These materials have a high specific surface area between 200 and 1500 m ² -g ^"! And have an intense band in the UN-vis spectrum centered around 220 nm, indicating the presence of Ti in tetrahedral environments. These catalysts are active and selective in olefin epoxidation reactions.

In a further step the material can be treated with a methylating agent. This methylation is carried out using R ₁ R ₂ R ₃ (R ') ^γ , Rι - (R') 2Y, Rι (R ') 3N or R1R-R3Y-ΝH- Y R1R2R3 where Ri, R ₂ and R ₃ are organic groups the same or different from each other and may be H or alkyl or aryl groups that may or may not be functionalized with amines, thiols, sulfonic groups, tetraalkylammoniums or acids. R 'is a hydrolysable group under the conditions of preparation such as alkoxide or halide groups. And it is a metal among which Si, Ge, Sn or Ti is preferred. Being the methylation procedures well known in the art. In this way, most of the Si-OH and Ti-OH groups present in the original material are functionalized. The chemical composition of the resulting methylated material is defined as: SiO ₂ : and YR _p O _2- p / 2: x TiO ₂ : a H ₂ O where R is hydrogen or an alkyl, aryl or polyaromatic group, the same or different from each other , which may or may not be functionalized with acid, amino, thiol, etc. groups. and it is directly linked to the atoms that make up the structure by means of CY, Y bonds can be Si, Ge, Sn or Ti, p can be varied between 1 and 3, and can take values between 0.0001 and 1, x can vary between 0.00001 and 0.25, preferably between 0.0001 and 0.1 already depends on the degree of hydration of the material and can vary between 0 and 2. Methylated materials have a high specific surface area between

100 and 1500 m ² -g ^"! And have an intense band in the UN-vis spectrum centered around 220 nrn, indicating the presence of Ti in tetrahedral environments. These catalysts are active and selective in olefin epoxidation reactions.

The following examples illustrate the preparation of these materials and their application to the selective oxidation reaction of olefins.

Example 1: Preparation of a mesoporous catalyst with MCM-48 structure containing Ti in its composition.

200 g of Cetyltrimethylammonium bromide (CTAB) are dissolved in 600 g of distilled water. To carry out the anion exchange of OH ^" for Br ^' , this solution is contacted with 500 g of Dowex SBR resin at room temperature for 12 hours. The resulting solution is filtered and the exchange process is repeated. The final concentration of OH is determined by titration with HC1 (0.1M) with phenolphthalein being 5.87-10 ^"4 moles-gdis, while the concentration of bromide ions in solution is below the detection limit of a bromide selective electrode, so that the concentration of CTA ⁺ ions is considered to be equal to that of OH ^" and the degree of anion exchange of 100%.

92.18 g of CTAOH solution are diluted with 280.60 g of water. To this solution is added 3,427 g of titanium tetraethoxide (TEOT) being kept under constant stirring at room temperature for 2 hours until complete dissolution of the

TEOT, adding 60.00 g of silica. The resulting mixture is stirred until complete homogeneity for 1 hour at room temperature and placed in an autoclave at 150 ° C for 6 hours The resulting gel is filtered, washed thoroughly and dried at 60 ° C for 12 hours. This material presents an X-ray diffraction diagram as shown in Figure 1, characteristic of the MCM-48 structure. In addition, this solid has a band at 210 nm in the UN-vis spectrum assigned to the presence of isolated Ti species in tetrahedral environments.

Example 2: Activation of a catalyst as described in example 1 by calcination.

3.00 g of material described in Example 1 are placed in a tubular quartz reactor and a dry nitrogen stream of 150 ml-min ^"1 is passed while the temperature is raised to 540 ° C to 3 ° C-min ^{" 1} . Once the temperature has been reached, the nitrogen flow is maintained for 60 minutes, after which the nitrogen flow is changed to a dry air flow of 150 ml-min ^"1. The calcination is prolonged for an additional 360 minutes and the solid it cools to room temperature.This heat treatment allows to completely remove all the organic occluded in the pores of the material.

This solid has a characteristic X-ray diffraction diagram of the MCM-48 structure, a specific surface area of 1230 m ^ g ^"1 , as well as a band in the UN-vis spectrum centered at 210 nm.

Example 3: Use of a material as described in example 2 as a selective catalyst in the cyclohexene oxidation reaction.

300 mg of the material described in Example 2, are introduced into a 60 ° C glass reactor, which contains 4500 mg of cyclohexene and 1538 mg of tertbutylhydroperoxide. The reaction mixture is stirred, and a reaction sample is taken at 0.5h. The conversion of cyclohexene with respect to the maximum possible is 34% with an epoxy selectivity of 100%. Example 4: Use of a material such as that described in example 2 as a selective catalyst in the oxidation reaction of α-pinene.

150 mg of the material described in example 2 are introduced into a 70 ° C glass reactor containing 1140 mg of α-pinene and 1890 of ethene hydroperoxide. The reaction mixture is stirred and a sample is taken at 0.5 hour reaction. The conversion of α-pinene is 15% and the yields to epoxide and caffeine aldehyde are

6% and 7%, respectively. The oxidant efficiency is 47%.

Example 5: Use of a material as described in example 2 as a selective catalyst in the terpinolene oxidation reaction.

150 mg of the material described in Example 2 is introduced into a 70 ° C glass reactor, which contains 1135 mg of terpinolene and 1380 mg of tertbutylhydroperoxide. The reaction mixture is stirred, and a reaction sample is taken at 0.5 hours. The conversion of terpinolene with respect to the maximum possible is 30% with a selectivity to the different epoxy of 62%.

Example 6: Methylation of a material as described in example 2.

2.0 g of the sample obtained in example 2 are dehydrated at 100 ° C and 10 ^-3 Tor for 2 hours. The sample is cooled, and at room temperature a solution of 1.88g of hexamethyldisilazane (CH ₃ ) ₃ Si-NH-Si (CH ₃ ) ₃ ) in 30g of toluene is added. The resulting mixture is refluxed at 120 ° C for 90 minutes and washed with toluene. The final product is dried at 60 ° C.

This solid presents a characteristic X-ray diffraction diagram of the MCM-48 structure, a specific surface area of 1195 m ² -g ^"! , As well as a band in the UN-vis spectrum centered at 210 nm. In addition the ⁹ spectrum Si-MAS-RMΝ has a resonance band at -10 ppm assigned to the presence of Si-C bonds. Example 7: Use of a material as described in example 6 as a selective catalyst in the cyclohexene oxidation reaction.

300 mg of the material described in example 6 are introduced into a glass reactor at 60 ° C, containing 4500 mg of cyclohexene and 1538 mg of tertbutylhydroperoxide. The reaction mixture is stirred, and a reaction sample is taken at 0.5 h. The conversion of cyclohexene with respect to the maximum possible is 55% with an epoxide selectivity of 100%.

Example 8: Use of a material such as that described in example 6 as a selective catalyst in the oxidation reaction of α-pinene.

150 mg of the material described in example 6 are introduced into a 70 ° C glass reactor containing 1140 mg of α-pinene and 1890 of ethene hydroperoxide. The reaction mixture is stirred and a sample is taken at 0.5 hour reaction. The conversion of α-pinene is 30% and the yields to epoxide and caffeine aldehyde are 23% and 3%, respectively. The oxidant efficiency is 92%.

Example 9: Use of a material as described in example 6 as a selective catalyst in the terpinolene oxidation reaction.

150 mg of the material described in Example 6 is introduced into a 70 ° C glass reactor, which contains 1135 mg of terpinolene and 1380 mg of tertbutylhydroperoxide. The reaction mixture is stirred, and a reaction sample is taken at 0.5 hours. The conversion of terpinolene with respect to the maximum possible, is 80% with a selectivity to the different epoxide of 70%

Example 10: Activation of a material as described in example 1 by chemical extraction.

5.5 g of sample as described in example 1 are treated with 276.4 g of a 0.05 M solution of sulfuric acid in ethanol. This suspension is stirred at reflux for one hour. The solid is recovered by filtration and washed with ethanol until neutral pH. The resulting solid is dried at 100 ° C for 30 minutes. Obtaining 3.51 g of product. The resulting solid is subjected to a second extraction stage in which 3.5 g of solid are added to a 0.15 M hydrochloric acid solution in ethanol / heptane (48:52), using a liquid / solid ratio of 50. This suspension is refluxed with constant stirring for 24 hours, filtering and washing with ethanol. The resulting solid is dried at 60 ° C for 12 hours.

This solid has a characteristic X-ray diffraction diagram of MCM-48 and a specific surface area of 1260m ² -g ^" , as well as a band in the UN-vis spectrum centered at 210 nm.

Example 11: Use of a material as described in example 10 as a selective catalyst in the cyclohexene oxidation reaction. 300 mg of the material described in Example 10 is introduced into a 60 ° C glass reactor, which contains 4500 mg of cyclohexene and 1538 mg of tertbutylhydroperoxide. The reaction mixture is stirred, and a reaction sample is taken at 0.5h. The conversion of cyclohexene with respect to the maximum possible is 80% with an epoxy selectivity of 91%.

Example 12: Use of a material such as that described in example 10 as a selective catalyst in the oxidation reaction of α-pinene.

150 mg of the material described in example 10 are introduced into a 70 ° C glass reactor containing 1140 mg of α-pinene and 1890 of ethene hydroperoxide. The reaction mixture is stirred and a sample is taken at 0.5 hour reaction. The conversion of α-pinene is 10% and the selectivities to the epoxide and the camouflage aldehyde are 60% and 8%, respectively. The oxidant efficiency is 30%.

Example 13: Use of a material as described in example 10 as a selective catalyst in the terpinolene oxidation reaction.

150 mg of the material described in Example 10 is introduced into a glass reactor at 60 ° C, containing 1135 mg of terpinolene and 1380 mg of tertbutylhydroperoxide.

The reaction mixture is stirred, and a reaction sample is taken at 0.5 hours. The conversion of terpinolene with respect to the maximum possible, is 42% with a selectivity to the different epoxide of 60%. Example 14: Methylation of a material as described in example 10.

2.0 g of the sample obtained in example 10 was dehydrated at 100 ° C and 10 ^-3 Tor for 2 hours. The sample is cooled, and at room temperature a solution of 1.88g of hexamethyldisilazane (CH ₃ ) ₃ Si-NH-Si (CH ₃ ) ₃ ) in 30g of toluene is added. The resulting mixture is refluxed at 120 ° C for 90 minutes and washed with toluene. The final product is dried at 60 ° C.

This solid presents a characteristic X-ray diffraction diagram of the MCM-48 structure, a specific surface area of 1205 m ² -g ^"1 , as well as a band in the UN-vis spectrum centered at 210 nm. In addition, the spectrum of ²⁹ Si-MAS-RMΝ has a resonance band at -10 ppm assigned to the presence of Si-C bonds.

Example 15: Use of a material as described in example 14 as a selective catalyst in the cyclohexene oxidation reaction.

300 mg of the material described in example 14 are introduced into a 60 ° C glass reactor, which contains 4500 mg of cyclohexene and 1538 mg of tertbutylhydroperoxide.

The reaction mixture is stirred, and a reaction sample is taken at 0.5h. The conversion of cyclohexene with respect to the maximum possible is 95% with an epoxy selectivity of 99%.

Example 16: Use of a material such as that described in example 14 as a selective catalyst in the oxidation reaction of α-pinene.

150 mg of the material described in example 14 are introduced into a 70 ° C glass reactor containing 1140 mg of α-pinene and 1890 of ethene hydroperoxide. The reaction mixture is stirred and sample is taken at 8 hours of reaction. The conversion of α-pinene is 49% and the selectivities to epoxide and caffeine aldehyde are of

83% and 7%, respectively. The oxidant efficiency is 50%. Example 17: Use of a material as described in example 14 as a selective catalyst in the terpinolene oxidation reaction.

150 mg of the material described in example 14 are introduced into a glass reactor at 60 ° C, containing 1135 mg of terpinolene and 1380 mg of tertbutylhydroperoxide. The reaction mixture is stirred, and a reaction sample is taken at 0.5 hours. The conversion of terpinolene with respect to the maximum possible, is 84% with a selectivity to the different epoxide of 64%.

Example 18: Use of a material such as that described in example 14 as a selective catalyst in the limonene oxidation reaction.

150 mg of the material described in Example 14 is introduced into a 70 ° C glass reactor, which contains 1157 mg of limonene and 1363 mg of tertbutylhydroperoxide.

The reaction mixture is stirred, and a reaction sample is taken at 0.5 hours. The conversion of limonene with respect to the maximum possible is 73% with a selectivity to the different epoxy of 75%.

Example 19: Use of a material such as that described in Example 14 as a selective catalyst in the isoprene oxidation reaction.

150 mg of the material described in example 14 are introduced into a glass reactor at 35 ° C, containing 2202 mg of isoprene and 901 mg of tertbutylhydroperoxide. The reaction mixture is stirred, and a reaction sample is taken at 0.5 hours. The conversion of isoprene with respect to the maximum possible is 54% with a selectivity to the different epoxide of 60%.

Example 20: Preparation of a mesoporous support with purely silicic MCM-48 structure.

200 g of Cetyltrimethylammonium bromide (CTAB) are dissolved in 600 g of distilled water. To carry out the anion exchange of OH ^" for Br ^" , this solution is contacted with 500 g of Dowex SBR resin at room temperature for 12 hours. The resulting solution is filtered and the exchange process repeated. The final concentration of OH is determined by titration with HC1 (0.1M) with phenolphthalein being 5.87-10 ^"4 moles-gdis, while the concentration of bromide ions in solution is below the detection limit of a bromide selective electrode, so that the concentration of CTA ⁺ ions is considered equal to that of OH ^" and the degree of anion exchange of 100%. 92.18 g of CTAOH solution are diluted with 280.60 g of water.To this solution is added 60.00 g of silica.The resulting mixture is stirred until complete homogeneity for 1 hour at room temperature and introduced into an autoclave at 150 ° C for 6 hours. The resulting gel is filtered , washed thoroughly and dried at 60 ° C. for 12 hours.This material presents an X-ray diffraction diagram as shown in Figure 2, characteristic of the structure MCM-48. 10.00 g of this material are arranged in a tubular quartz reactor and a dry nitrogen stream of 150 ml-min ^"1 is passed while the temperature is raised to 540 ° C to 3 ° C-min ^'1 . Once the temperature has been reached, the nitrogen flow is maintained for 60 minutes, after which the nitrogen flow is changed to a dry air flow of 150 ml-min ^"1. The calcination is prolonged for an additional 360 minutes and the solid it cools to room temperature.This heat treatment allows to completely remove all the organic occluded in the pores of the material.

This solid presents a characteristic X-ray diffraction diagram of the MCM-48 structure and a specific surface area of 1080 m -g ^" .

Example 21: Incorporation of the active species of titanium into the mesoporous support described in example 20.

The incorporation of titanium is carried out by anchoring a titanium compound on the surface of the precursor described in example 20.

5 g of the material described in example 20 are dehydrated at 300 ° C and vacuum 10 ^"3 mm Hg for 2 hours, adding a solution containing 0.079 g of titanocene dichloride in 45 g of anhydrous chloroform. The resulting suspension is stirred at room temperature for 1 hour under Ar atmosphere. A suspension containing 0.063 g of triethylamine in 10 g of chloroform is added to this suspension, white gas evolution is observed and the color of the solution changes from red-orange to yellow "orange. Stirring is prolonged for one hour. The solid is recovered by filtration and the excess reagents are removed by thorough washing with dichloromethane. The resulting solid is calcined at 540 ° C under N2 atmosphere for 1 hour. heat treatment for 6 more hours in air. Under these conditions all the organic present in the material is removed.

The material has no significant structural or textural differences with respect to the purely siliceous precursor, responding to the following molar composition: SiO ₂ : 0.004 TiO ₂ : 0.8H ₂ O

The UN-vis spectrum of this material has a narrow band at 220 nm assigned to the formation of monomeric species of titanium.

Example 22: Use of a material such as that described in example 21 as a selective catalyst in the cyclohexene oxidation reaction.

300 mg of the material described in example 21, are introduced into a glass reactor at 60 ° C, containing 4500 mg of cyclohexene and 1538 mg of tertbutylhydroperoxide.

The reaction mixture is stirred, and a reaction sample is taken at 0.5 h. The conversion of cyclohexene with respect to the maximum possible is 32% with an epoxy selectivity of 97%.

Example 23: Use of a material such as that described in example 21 as a selective catalyst in the oxidation reaction of α-pinene.

150 mg of the material described in example 21 are introduced into a 70 ° C glass reactor containing 1140 mg of α-pinene and 1890 of ethene hydroperoxide. The reaction mixture is stirred and sample is taken at 8 hours of reaction. The conversion of α-pinene is 12% and the yields to epoxide and caffeine aldehyde are 8

% and 2%, respectively. The oxidant efficiency is 33%.

Example 24: Methylation of a material as described in example 21.

2.0 g of the sample obtained in Example 21 are dehydrated at 100 ° C and 10 ^"3 Tor for 2 hours. The sample is cooled, and at room temperature a solution of 1.88g of hexamethyldisilazane (CH ₃ ) ₃ Si-ΝH is added -If (CH ₃ ) 3) in 30g of toluene, the resulting mixture is refluxed at 120 ° C for 90 minutes and washed with toluene.The final product is dried at 60 ° C.

This solid presents a characteristic X-ray diffraction diagram of the MCM-48 structure, a specific surface area of 1003

as well as a band in the UN-vis spectrum centered at 210 nm. In addition, the spectrum of ²⁹ Si-MAS-RMΝ has a resonance band at -10 ppm assigned to the presence of Si-C bonds.

Example 25: Use of a material as described in example 24 as a selective catalyst in the cyclohexene oxidation reaction.

300 mg of the material described in example 24 are introduced into a glass reactor at 60 ° C, containing 4500 mg of cyclohexene and 1538 mg of tertbutylhydroperoxide.

The reaction mixture is stirred, and a reaction sample is taken at 0.5 h. The conversion of cyclohexene with respect to the maximum possible is 47% with an epoxy selectivity of 99%.

Example 26: Use of a material as described in example 24 as a selective catalyst in the oxidation reaction of α-pinene.

150 mg of the material described in example 24 are introduced into a 70 ° C glass reactor containing 1140 mg of α-pinene and 1890 of ethene hydroperoxide. The reaction mixture is stirred and a sample is taken at 0.5 hour reaction. The conversion of α-pinene is 28% and the yields to epoxide and caffeine aldehyde are

22% and 4%, respectively. The oxidant efficiency is 44%.

Example 27: Use of a material such as that described in example 24 as a selective catalyst in the terpinolene oxidation reaction.

150 mg of the material described in Example 24 is introduced into a 70 ° C glass reactor, which contains 1135 mg of terpinolene and 1380 mg of tertbutylhydroperoxide.

The reaction mixture is stirred, and a reaction sample is taken at 0.5 hours. The conversion of terpinolene with respect to the maximum possible is 78% with a selectivity to the different epoxides of 62%. Example 28: Use of a material such as that described in example 24 as a selective catalyst in the limonene oxidation reaction.

150 mg of the material described in Example 24 is introduced into a 70 ° C glass reactor, which contains 1157 mg of limonene and 1363 mg of tertbutylhydroperoxide. The reaction mixture is stirred, and a reaction sample is taken at 0.5 hours. The conversion of limonene with respect to the maximum possible, is 77% with a selectivity to the different epoxy of 72%.

Example 29: Use of a material such as that described in example 25 as a selective catalyst in the isoprene oxidation reaction.

150 mg of the material described in example 24 are introduced into a 27 ° C glass reactor, containing 2202 mg of isoprene and 901 mg of tertbutylhydroperoxide. The reaction mixture is stirred, and a reaction sample is taken at 0.5 hours. The conversion of isoprene with respect to the maximum possible is 25% with a selectivity to the different epoxide of 53%.

Claims

1.- Use of mesoporous materials type MCM-48 formed by Si and Ti in the form of titanosilicates for the oxidation of organic compounds.

2.- Use of mesoporous materials type MCM-48 formed by Si and Ti and which also contain organic groups bonded to the atoms of Si and / or Ti that make up the mesoporous structure, as oxidation catalysts of organic compounds.

3.- Use of mesoporous materials type MCM-48 that respond to the chemical formula:

SiO ₂ : x TiO ₂ as catalysts for the oxidation of organic compounds and which are obtained from a precursor with MCM-48 structure of chemical formula:

SiO ₂ : x TiO ₂ : nS where x can vary between 0.0001 and 0.5, S can be an organic compound, such as a cationic, anionic or neutral surfactant. Cationic surfactants respond to the formula RιR2R3RιQ ⁺ where Q is nitrogen or phosphorus and where at least one of the substituents Ri, R ₂ , R? or Rt is an aryl or alkyl group containing more than 6 carbon atoms and less than 36, and each of the remaining Ri, R2, R ₃ or R * groups is a hydrogen or an alkyl or aryl group with less than five carbons . Also included within the cationic surfactants that can be incorporated into the gel composition are called gemstone surfactants,

or R ₁ RR ₃ Q (R ₄ R5QR ₆ QR ₄ R ₅ ) Q _n RιR ₂ R ₃ where Q is a nitrogen or phosphorus and at least one of the RrR substituents; it is an alkyl or aryl group with more than six carbon atoms and less than 36, and each of the remaining Ri-Rδ groups are hydrogens or alkyl or aryl groups with memos of five carbon atoms or mixtures thereof. In these cases two of the Ri, R ₂ , R ₃ or Rt groups may be interconnected giving rise to cyclized compounds. Cationic surfactants are introduced into the synthesis gel composition in the form of hydroxide, halide, nitrate, sulfate, carbonate or silicate or mixtures thereof. Non-limiting examples of them are cetyltrimethylammonium, dodecyltrimethylammonium, cetylpyridinium, cetyltrimethylphosphonium, etc.

S may also refer to a neutral surfactant, in which case they respond to the formula R1R2R3Q where Q is nitrogen or phosphorus and where at least one of the substituents Ri, R _2, or R ₃ is an aryl or alkyl group containing more than 6 carbon atoms and less than 36, and each of the remaining Ri groups, _R2 or R3 is a hydrogen or an alkyl or aryl group with less of five carbons, non-limiting examples are dodecylamine, cetylamine and cetylpyridine. Compounds that respond to the nR-EO formula consisting of an alkyl polyethylene oxides, alkyl aryl polyethylene oxides and alkyl polypropylene and alkylene ethylene copolymers may also act as neutral surfactants, commercial surfactants termed Tergitol 15-S being non-limiting examples. 9, Triton X-114, Igepal RC-760, Pluronic 64 L, Tetronic and Sorbitan. Esters derived from fatty acids obtained by reaction with short chain alcohols, sugars, amino acids, amines and polymers or copolymers derived from polypropylene, polyethylene, polyacrylamide or polyvinyl alcohol may also be included in the formulation, non-limiting examples are lisolecithin, lecithin, dodecyl ether of pentaoxyethylene, phosphatyldilauryldiethanolamine, digalactose diglyceride and monogalactose diglyceride. The surfactant can also be an anionic surfactant that respond to the formula RQ ^" where R is an aryl or alkyl group containing more than 6 carbon atoms and less than 36, and Q is a sulfate, carboxylic, phosphate or sulfate group, examples being Non-limiting dodecylsulfate, stearic acid, Aerosol OT and phospholipids such as phosphatyl choline and diethanolamine phosphatyl, and n can vary between 0 and 0.5.

In which the organic material corresponding to group S is extracted chemically.

4. The use of mesoporous materials type MCM-48 as catalysts for the oxidation of organic compounds, which are prepared as described in claim 3 but in which at a later stage they undergo a silanization process giving rise to the formation of species that contain Si-C bonds.

5. The use of mesoporous materials type MCM-48 as catalysts for the oxidation of organic compounds, which are prepared as described in claim 3, but which is distinguished from these in which the groups containing Si-C bonds are introduced during the synthesis stage prior to the elimination of the organic.

6. The use of mesoporous materials type MCM-48 as catalysts for the oxidation of organic compounds, which are prepared as described in claim 3 but which differ from these in that the organic corresponding to group S is eliminated by a step of calcination.

7. The use of mesoporous materials type MCM-48 as catalysts for the oxidation of organic compounds, which are prepared as described in claim 6 but in which at a later stage they undergo a silanization process giving rise to the formation of species that contain Si-C bonds.

8. The use of mesoporous materials type MCM-48 as catalysts for the oxidation of organic compounds, which are prepared as described in claim 3 in which the organic corresponding to group S is eliminated by means of an extraction process in alcohol / water mixtures under supercritical conditions, or by treatment with a solution of a mineral or organic acid in a solvent that may be water, alcohol, hydrocarbons or mixtures thereof.

9. The use of mesoporous materials type MCM-48 as catalysts for the oxidation of organic compounds, which are prepared as described in claims 4 and 7 in which silanizing agents are used compounds that respond to the formula RιR ₂ R ₃ (R ') Y, RιR ₂ (R') 2Y, Rι (') 3Y or R, R ₂ R ₃ Y-NH-Y R ₁ R ₂ R ₃ , where Ri, R ₂ and R ₃ are groups organic compounds that are the same or different from each other and may be H or alkyl or aryl groups that may or may not be functionalized with amines, thiols, sulfonic groups, tetraalkylammoniums or acids, R 'is a hydrolyzable group under the conditions of preparation such as alkoxide groups or halide And it is a metal among which Si, Ge, Sn or Ti is preferred. Being the methylation procedures well known in the art. In this way, most of the Si-OH and Ti-OH groups present in the mesoporous materials type MCM-48 are functionalized.

10.- Use of mesoporous materials type MCM-48 as supports of the active phases of titanium resulting in active catalysts for the oxidation of organic compounds. The precursors of these supports respond to the chemical formula:

SiO ₂ : n S where x can vary between 0.0001 and 0.5, S can be an organic compound, such as a cationic, anionic or neutral surfactant. Cationic surfactants respond to the formula R ₁ R ₂ R ₃ R ₄ Q ⁺ where Q is nitrogen or phosphorus and where at least one of the substituents Ri, R ₂ , R ₃ or R is an aryl or alkyl group containing more than 6 atoms of carbon and less than 36, and each of the remaining Ri, R ₂ , R ₃ ot groups is a hydrogen or an alkyl or aryl group with less than five carbons. Also included within the cationic surfactants that can be incorporated into the gel composition are the so-called geminal surfactants, R ₁ R ₂ R ₃ QR ₄ QR ₁ R ₂ R ₃ or R ₁ R ₂ R ₃ Q (R ₄ R ₅ QR ₆ QR ₄ R ₅ ) Q _n R ₁ R ₂ R ₃ where Q is a nitrogen or phosphorus and at least one of the substituents R1-R5 is an alkyl or aryl group with more than six carbon atoms and less than 36, and each one of the remaining R ₁ -R ₅ groups are hydrogens or alkyl or aryl groups with memos of five carbon atoms or mixtures thereof. In these cases two of the Ri, R ₂ , R ₃ or R _{4 groups} can be interconnected giving rise to cycled compounds. Cationic surfactants are introduced into the synthesis gel composition in the form of hydroxide, halide, nitrate, sulfate, carbonate or silicate or mixtures thereof. Non-limiting examples of them are cetyltrimethylammonium, dodecyltrimethylammonium, cetylpyridinium, cetyltrimethylphosphonium, etc.

S may also refer to a neutral surfactant, in which case they respond to the formula RiR ₂ R ₃ Q where Q is nitrogen or phosphorus and where at least one of the substituents Ri, R ₂ , or R ₃ is an aryl or alkyl group containing more than 6 carbon atoms and less than 36, and each of the remaining Ri, R ₂ or R _{3 groups} is a hydrogen or an alkyl or aryl group with less than five carbons, non-limiting examples being dodecylamine, cetylamine and cetylpyridine. Compounds that respond to the nR-EO formula consisting of an alkyl polyethylene oxides, alkyl aryl polyethylene oxides and alkyl polypropylene and alkylene ethylene copolymers may also act as neutral surfactants, commercial surfactants termed Tergitol 15-S being non-limiting examples. 9, Triton X-114, Igepal RC-760, Pluronic 64 L, Tetronic and Sorbitan. Esters derived from fatty acids obtained by reaction with short chain alcohols, sugars, amino acids, amines and polymers or copolymers derived from the same may also be included in the formulation polypropylene, polyethylene, polyacrylamide or polyvinyl alcohol, non-limiting examples are lysolecithin, lecithin, dodecyl pentaoxyethylene ether, phosphatyldylauryldiethanolamine, digalactose diglyceride and monogalactose diglyceride. The surfactant can also be an anionic surfactant that respond to the formula RQ ^' where R is an aryl or alkyl group containing more than 6 carbon atoms and less than 36, and Q is a sulfate, carboxylic, phosphate or sulfate group, examples being non-limiting dodecyl sulfate, stearic acid, Aerosol OT and phospholipids such as phosphatyl choline and diethanolamine phosphatyl. and n can vary between 0 and 0.5.

In which the organic material coresponding to group S is extracted chemically and / or by calcination thereof.

11.- Use of MCM-48 type mesoporous materials as catalysts for the oxidation of organic compounds, which respond to the chemical formula:

SiO ₂ : x TiO ₂ Y which are obtained by supporting active species of titanium on mesoporous supports type MCM-48 as described in claim 10 and where x can vary between 0.0001 and 0.5. As precursors of the active species of Titanium, titanium compounds are used among which are preferred: titanium halides, titanium alkoxides, dichlorotitanocene or titanium complexes in which the titanium atom is coordinated by a dionate group such as acetylacetonate, ammonium hexafluorotitanate or sodium and any ionic complex or salt that contains titanium in its composition and may be capable of reacting with a Si-OH group. Excess reagents are removed by washing and / or heat treatment in an inert atmosphere, followed by calcination in air under conditions in which organic matter or halogens that may be present in the final MCM-48 type mesoporous titanosilicate material is removed.

12. The use of mesoporous materials type MCM-48 as catalysts for the oxidation of organic compounds, which are prepared as described in claim 11 but in which at a later stage they undergo a silanization process resulting in the formation of species that contain Si-C bonds.

13. The use of mesoporous materials type MCM-48 as catalysts for the oxidation of organic compounds, which are prepared as described in claim 12 in which as silanizing agents compounds are used that respond to the formula R ₁ R ₂ R ₃ (R ') Y, RiR ₂ (R') 2Y, Rι (R ') 3Y or R ^ RsY-NH-Y R1R2R3, where Ri, R ₂ and R3 are organic groups the same or different from each other and can be H or alkyl or aryl groups that may or may not be functionalized with amines, thiols, sulfonic groups, tetraalkylammoniums or acids, R 'is a hydrolyzable group under the conditions of preparation such as alkoxide or halide groups. And it is a metal among which Si, Ge, Sn or Ti is preferred. Being the methylation procedures well known in the art. In this way, most of the Si-OH and Ti-OH groups present in the mesoporous materials type MCM-48 are functionalized.

14. The use of mesoporous materials type MCM-48 as catalysts for the oxidation of organic compounds, which are prepared as described in claims 3 to 9 and 11 to 13, and in which an organic hydroperoxide is used as oxidizing agent as for example, without being limiting examples, eumene hydroperoxide, terbutylhydroperoxide and ethyl benzyl hydroperoxide.

15.- An oxidation process of organic compounds to the epoxy, aldehyde or ketone co-sponsor that is characterized by being carried out in a batch, CSTR or continuous reactor of fixed or fluidized bed using a mesoporous solid type MCM-48 containing silicon and titanium in its composition, and optionally any group containing Si-C or Ti-C bonds, and prepared according to claims 1 to 13, and as an oxidizing agent organic hydroperoxides such as, without being limiting, terbutylhydroperoxide, eumene hydroperoxide or hydroperoxide of ethylbenzene.

16.- A process of oxidation of linear, branched or cyclic olefins, such as propylene, hexene, octene, cyclohexene, isoprene, terpenes such as α-pinene, terpinolene, limonene, α-cedrene, longifolene and caripylene to the corresponding epoxides, aldehydes or ketones characterized by being carried out in a batch, CSTR or fixed bed continuous reactor using a mesoporous solid type MCM-48 containing silicon and titanium in its composition, and optionally some group containing Si-C or Ti bonds -C, and prepared according to claims 1 to 13, and as an oxidizing agent organic hydroperoxides, for example, without being limiting, terbutylhydroperoxide, eumene hydroperoxide or ethylbenzene hydroperoxide.

17.- A mesoporous material type MCM-48 whose composition responds to the chemical formula:

wherein Y represents one or more elements of valence 4, preferably Si, Ge, Ti, Zr or Sn, R is hydrogen or an alkyl, aryl, polyaromatic group that may or may not be functionalized with acid, amino, thiol, etc. groups. and is linked to the structure through CY links. p can be varied between 10 ^"5 and 0.75. Z is a minor tetravalent element in the composition (10 ^{" 5} <and <0.25) which can be Si, Ge, Ti, N, Zr or Sn.

18.- A mesoporous material type MCM-48 whose composition responds to the formula:

wherein Y represents one or more elements of valence 4, preferably Si, Ge, Ti, Zr or Sn, R is hydrogen or an alkyl, aryl, polyaromatic group that may or may not be functionalized with acid, amino, thiol, etc. groups. and is directly linked to the atoms that make up the structure through CY bonds. p can be varied between 10 ^'5 and 0.75. Z is a minor tetravalent element in the composition (10 ^'5 <and <0.25) which may be Si, Ge, Ti, N, Zr or Sn. And where S represents a cationic, neutral or anionic surfactant.

19.- A single-step preparation process of a mesoporous material with structure type MCM-48 according to claim 17 characterized in that a precursor RjYL _4- j is introduced in the synthesis stage where Y can be Si, Ge, Sn, Ti or Zr and R an hydrogen or organic group with alkyl chains of 1 to 22 carbons, aromatic or polyaromatic being preferred. R may also contain organic functional groups such as amines, acids, halides, esters, sulfonic groups and thiols. L is a group that can be hydrolyzed in the synthesis medium, with halides, amino, ethoxide, methoxide, propoxide, butoxide and alkoxides being preferred in general, such as, for example, methyltriethoxysilane, methyltrichlorogerman, iodopropyltrimethoxysilane, titanocene dichloride, methyltrichloroesilane, hexamethyldichloroethyl, hexamethyldichloridene, hexamethyldichloroethyl, hexamethyldichloroethyl, hexamethyldichloroethyl ether

20. A single step preparation process of a mesoporous material with structure type MCM-48 according to claim 18 wherein S is a cationic, neutral or anionic surfactant. Cationic surfactants respond to the formula RιR2R3 Q where Q is nitrogen or phosphorus and where at least one of the substituents R _1} R2, R3 or Rf is an aryl or alkyl group containing more than 6 carbon atoms and less than 36., and each of the remaining Ri, R2, R3 or R _{t groups} is a hydrogen or an alkyl or aryl group with less than five carbons. Also included within the cationic surfactants that can be incorporated into the gel composition are called gemstone surfactants, RιR2R3QR4QRι 2R3 or RιR2R ₃ Q (R ₄ R ₅ QR ₆ QR ₄ R5) _n QR ₁ R ₂ R ₃ where Q is a nitrogen or phosphorus and at least one of the substituents R1-R5 is an alkyl or aryl group with more than six carbon atoms and less than 36, and each of the remaining R1-R5 groups are hydrogens or alkyl or aryl groups with memes of five carbon atoms or mixtures of them. In these cases two of the R _ls R ₂ , R ₃ or Rt groups may be interconnected giving rise to cyclized compounds. Cationic surfactants are introduced into the synthesis gel composition in the form of hydroxide, halide, nitrate, sulfate, carbonate or silicate or mixtures thereof. Non-limiting examples of them are cetyltrimethylammonium, dodecyltrimethylammonium, cetylpyridinium, cetyltrimethylphosphonium, etc.

S may also refer to a neutral surfactant, in which case they respond to the formula RιR ₂ R ₃ Q where Q is nitrogen or phosphorus and where at least one of the substituents Ri, R ₂ , or R3 is an aryl or alkyl group containing more of 6 carbon atoms and less than 36., and each of the remaining Ri, R ₂ or R _{3 groups} is a hydrogen or an alkyl or aryl group with less than five carbons, non-limiting examples are dodecylamine, cetylamine and cetylpyridine. Compound neutral surfactants that respond to the nR-EO formula consisting of an alkyl polyethylene oxides, alkyl aryl polyethylene oxides and alkyl polypropylene and alkylene ethylene copolymers may also act as non-limiting examples, commercial surfactants termed Tergitol 15 S 9, Triton X-114, Igepal RC-760, Pluronic 64 L, Tetronic and Sorbitan. Esters derived from fatty acids obtained by reaction with short chain alcohols, sugars, amino acids, amines and polymers or copolymers derived from polypropylene, polyethylene, polyacrylamide or polyvinyl alcohol may also be included in the formulation, non-limiting examples being lisolecithin, lecithin, dodecyl ether of pentaoxyethylene, dilauryldiethanolamine phosphatyl, digalactose diglyceride and monogalactose diglyceride. The surfactant can also be an anionic surfactant that respond to the formula RQ ^" where R is an aryl or alkyl group containing more than 6 carbon atoms and less than 36, and Q is a sulfate, carboxylic, phosphate or sulfate group, examples being non-limiting dodecyl sulfate, stearic acid, Aerosol OT and phospholipids such as phosphatyl choline and diethanolamine phosphatyl.

21. A single step preparation process of a mesoporous material with structure type MCM-48 according to claims 18 and 19 in which the surfactant is removed by means of an extraction process by treatment with a solution of a mineral acid or organic in a solvent that can be water, alcohol, hydrocarbons or mixtures thereof.

22. Preparation process according to claims 18, 19 and 20 and wherein a material according to claim 16 is subjected to a subsequent stage of silanization resulting in the formation of new species containing Si-C and / or Ti-C bonds .