RU2159675C1 - Method of activating titanium-containing silicate, titanium-containing silicate catalyst, and method of oxidizing organic substrate - Google Patents

Abstract

FIELD: oxidation and organic reaction catalysts. SUBSTANCE: activation of titanium-containing silicate depicted by general formula ×TiO₂.(1-x)SiO₂, in which x ranges from 0.0001 to 0.04, is accomplished by hydrogen peroxide in aqueous medium in presence of fluoride ion or fluorine-containing compound precursors. Activated catalyst is advantageously employed in processes of oxidation of organics with hydrogen peroxide, in particular, in aromatics' hydroxylation reactions, in carbonyl compounds' amoxymation reactions, olefins' epoxidation reactions, and nitrogen-containing compounds' oxidation reactions. EFFECT: increased catalyst activity. 33 cl, 9 tbl, 56 ex

Description

 The invention relates to a method for improving the catalytic properties of titanium-containing silicalite of general formula (I) and its use in oxidation processes: organic substrates and amoximation of carbonyl-containing compounds with hydrogen peroxide.

 It is known that titanium-containing zeolites with an MFI structure (TS-I) are used as catalysts in the reactions of direct oxidation by hydrogen peroxide of such substrates as aromatic hydrocarbons (US Pat. No. 4,369,783), olefins (EP 100119), nitrogen-containing compounds (secondary amines - patent US 4918194, ammonia - patent US 5320819) and amoximation reactions of carbonyl-containing compounds (patent US 4794198, EP 496385).

 It is also known that the catalytic properties of zeolites, manifested by them in reactions involving hydrogen peroxide, can be significantly improved by appropriate activating treatment.

 For example, EP 230949 describes a method for producing epoxides from olefins with the participation of hydrogen peroxide using titanium-containing silicalite which is treated with a neutralizing agent before or during the epoxidation process as a catalyst.

In a series of neutralizing agents, this EP patent describes the use of organic silicon-containing compounds of the formula X-Si (R) _{3 type} or water-soluble substances obtained from cations of group I or II with varying basicity.

 This method, however, has some limitations associated, for example, with the reactivity of organic silicon compounds. Therefore, after processing the catalyst, a washing step is necessary to remove the silanizing agent, which, if it is not effective (quantitative), can cause side reactions at the epoxidation stage with solvents and products formed during the main reaction.

 As for the use of alkaline substances with cations of group I and II, the limiting factor is associated with their property of solubility in water, as a result of which the solvent used in the reaction must necessarily contain water from the very beginning for their complete dissolution if the neutralization procedure is carried out during the reaction.

US patent 4,794,198 describes a process for the amoximation of carbonyl compounds, in particular cyclohexanone, into the corresponding oximes, which uses titanium-containing silicalite (TS-I) pretreated with aqueous solutions of hydrogen peroxide and / or in the presence of at least 0.5 equivalent / liter of acids having pKa ≤ 5 (preferably H ₂ SO ₄ , HCl, HNO ₃ , H ₃ PO ₄ ).

 However, when reproducing this method, relatively low productivity of the process, calculated as the amount of oxime obtained per hour, per unit weight of titanium, is obtained. Therefore, the production of oximes with good yield indices implies the need for large amounts of catalyst and a long reaction time, which is disadvantageous from an economic point of view and taking into account the procedures for isolation and purification of the final products obtained.

 In addition, the catalysts activated by the above methods are specific for each reaction.

 According to the present invention, it has now been found that the catalytic properties of titanium-containing silicalite (TS-I) in the above reactions can be improved if these catalysts are subjected to hydrogen peroxide activation in an aqueous medium before use in the presence of fluoride ions or other types of anions containing fluorine.

 The main advantage of the method of the present invention is the higher activity and selectivity of the activated catalyst. This actually simplifies the procedures for the allocation of products in the recycling of reagents with positive effects of an economic nature. In addition, the catalysts activated according to the method of the present invention are equally effective for all reactions catalyzed by titanium-containing silicalites (oxidation and amoximation).

 In accordance with the foregoing, the first object of the present invention is a method for improving the catalytic properties of a titanium-containing silicalite of formula (I) by activating a catalyst (1), hydrogen peroxide in an aqueous medium in the presence of fluoride ion precursors or other types of fluoride-containing anions.

Another object of the present invention is a method for the oxidation of organic substances and a method for maximizing carbonyl-containing compounds with hydrogen peroxide, in which a titanium-containing silicalite of the formula (I) is used as a catalyst, activated with H ₂ O ₂ in an aqueous medium in the presence of fluoride ion precursors or other types of anions, containing fluorine.

The catalysts used in the method of the present invention are selected from those that have the general formula (I) xTiO ₂ • (IX) SiO ₂ , where x = 0.0001 - 0.04.

 The above titanium-containing silicalites can be obtained in accordance with the method described in US patent 4410501, which also shows their structural characteristics.

 Alternatively, these catalysts can be used in the form of microspheres with high mechanical resistance, obtained by the methods described in US patents 4954653 and 4701428.

 In fact, it has been observed that amorphous silica used as a TS-I submicron particle ligand does not threaten the effectiveness of the catalyst activation process.

 Titanium-containing silicalites, in which part of the titanium atoms are replaced by other metals, for example, atoms of boron, aluminum, iron and gallium, can also be used. Such titanium substituted silicalites and methods for their preparation are described in European Patent Applications 226257, 226258 and 266825.

Examples of fluoride ion precursors that can be used for the purposes of the present invention are: hydrofluoric acid, ammonium fluorides, alkali metal fluorides (NaF, KF, LiF, KHF ₂ ) or other metals soluble in water, such as, for example, AlF ₃ • 3H ₂ O.

In addition, water-soluble inorganic fluorine derivatives can be used in the form of an acid, for example, hydrofluoric acid (H ₂ SiF ₆ ), hydrogen fluoride (HBF ₄ ) and phosphorus (5) hydrofluoric acid (HPF ₆ ) or in salt form, for example with NH ₆ OH.

Among the fluorinated compounds mentioned above, ammonium derivatives are preferred, in the form of an ammonium ion and optionally can be present as a radical in the catalyst structure, can be easily removed by heat treatment at temperatures above 400 ^o C. Ammonium fluoride and ammonium bifluoride (NH ₄ F, NH ₄ HF ₂ ) are particularly preferred.

In order to adjust the pH of the reaction medium, aqueous solutions of fluorine compounds in acid form can be partially alkalized with, for example, NH ₄ OH.

The concentration of fluorinated compounds in the reaction medium is determined depending on the concentration and structure of titanium-containing silicalite. When expressing the reagents in moles of F or Ti, respectively, the molar ratio F / Ti can vary from 0.5 to 3.0. Under preferred conditions, when NH ₄ F or NH ₄ HF _{2 is used} , this ratio can vary from 1.0 to 2.5.

The activation reaction usually uses an aqueous solution of hydrogen peroxide with a concentration of 30-35% by weight. The amount of hydrogen peroxide is controlled depending on the titanium content. Under preferred conditions, the molar ratio of H ₂ O ₂ / Ti can vary from 3.0 to 15, preferably from 6 to 12.

The combination of the fluorinated compound H ₂ O ₂ is a fundamental factor, since the activation process without either of these two reagents is not very effective. The presence of hydrogen peroxide in the reaction system causes an increase in the degree of solubilization of Ti (wt.% Ti removed from titanium-containing silicalite), the control of which is a critical moment of the activation process.

 It was noted that depending on the chemical composition of the catalyst, the type and concentration of the fluorine-containing compound, and other reaction conditions (temperature, processing time), the amount of Ti solubilized with respect to its initial content in the catalyst can vary from 1 to 60 wt%.

After the activation procedure, the UV spectrum (visible) of TS-I undergoes a change, more or less distinct, consisting in the appearance of a new absorption band, concentrated at 39000 cm ^-1 . This modification is visible in FIG. 1, which shows UV (visible.) - spectrum TS-I of example 1 before (spectrum A) and after (spectrum B) processing.

 In a preferred embodiment, when ammonium fluoride or bifluoride and a titanium-containing silicalite with a high Ti content (2.1-2.4 wt.% Ti) are used, the degree of solubilization, varying from 30 to 50%, results in highly selective and active catalysts.

 When working with catalysts having a lower titanium content (1.5 wt.% Ti), their catalytic properties are similar to those observed with the aforementioned catalysts, when the degree of solubilization of Ti is higher than 10%.

 The temperature and duration of the catalyst activation process are selected depending on the desired degree of solubilization of Ti.

The activation reaction is usually carried out at a temperature of from 20 ^o C to 100 ^o C. It is preferable to use a temperature range in the range of 60-90 ^o C and the corresponding time intervals, which at a constant temperature last from 1 to 6 hours.

 The catalyst activation reaction can be carried out by first preparing a suspension of the catalyst in an aqueous solution of fluoride ion precursors and hydrogen peroxide, followed by thermostating of this suspension at a selected temperature.

 According to another embodiment of the method of the present invention, hydrogen peroxide can be added to an aqueous suspension of reagents previously thermostated at the reaction temperature.

 At the end of the activation procedure, the catalyst is isolated from the reaction medium and washed repeatedly with deionized water. After washing with water, washing with water-soluble low boiling point solvents, such as acetone, may follow to remove the absorbed water and accelerate drying.

This procedure, which is not critical, can be performed under vacuum at temperatures below 100 ^o C or in air at 110-120 ^o C. After drying, the catalyst is calcined at temperatures from 400 ^o C to 600 ^o C to ensure complete removal of ions that could be adsorbed, such as, for example, ammonium ion.

 The catalysts obtained by the method of the present invention are active and selective in the reactions of oxidation of organic substrates and amoximation of carbonyl-containing compounds using hydrogen peroxide.

 In particular, activated catalysts can be successfully used in hydroxylation reactions of aromatic compounds, amoximation reactions of carbonyl-containing compounds, epoxidation reactions of olefinic compounds and oxidation reactions of nitrogen-containing compounds.

 The amount of catalyst used, as well as the reaction conditions, is selected depending on the oxidizable substrate.

 Aromatic compounds that can be used in the method of the present invention can be selected, for example, from benzene, toluene, ethylbenzene, chlorobenzene and anisole. The hydroxylation reaction can be carried out as described, for example, in US patent 4369783.

где R₁, R₂, R₃ и R₄, являясь одинаковыми или различными, представляют собой атом водорода или алкильную группу с 1-4 атомами углерода. В соединении формулы (II) R₁, R₂, R₃ и R₄ предпочтительно представляют собой атом водорода.The oxidation of benzene to phenol with hydrogen peroxide is preferably carried out in the presence of solvents selected from compounds of formula (II)

where R ₁ , R ₂ , R ₃ and R ₄ , being the same or different, represent a hydrogen atom or an alkyl group with 1-4 carbon atoms. In the compound of formula (II), R ₁ , R ₂ , R ₃ and R _{4 are} preferably a hydrogen atom.

 It is advisable to use the solvent in amounts of from 10 to 90% by weight of the weight of the reaction mixture. It is more advisable to use a solvent in amounts of from 20 to 80% by weight of the weight of the reaction mixture.

 In fact, it was noticed that when working under these conditions, secondary reactions are inhibited, which cause the formation of dihydroxybenzenes, such as catechol and hydroquinone, while the phenol yield, calculated as the molar ratio of the resulting oxidized compound and the aromatic substrate that has undergone reaction, remains consistent with that obtained using an inactive catalyst.

 The activated catalyst is mainly used in amounts of from 2% to 40% by weight relative to benzene. Preferably, the amounts of catalyst used are from 5 to 15% by weight based on benzene.

 Hydrogen peroxide is added to the reaction mixture in amounts of from 5 to 50% in moles based on benzene, preferably from 10 to 30% in moles.

 Usually, hydrogen peroxide solutions are used with a concentration of from 1 to 60% by weight, preferably from 3 to 30% by weight.

 Benzene is used in amounts of 10 to 80% by weight relative to the weight of the reaction mixture.

 Benzene is preferably used in an amount of 30 to 60% by weight of the reaction mixture.

Preferably, the reaction is carried out at a temperature of from 50 to 95 ^o C. Even more preferably, the temperature is in the range from 70 to 85 ^o C.

 The duration of the reaction necessary for the complete consumption of hydrogen peroxide depends on the reaction conditions used.

 Upon completion of the hydroxylation reaction, the reaction product is isolated together with the unreacted substrate using methods commonly used for this, such as, for example, fractional distillation and crystallization.

 The catalyst obtained by the method of the present invention is thus extremely active in the amoximation reaction of carbonyl-containing compounds, especially cyclohexanone, since it increases the productivity of the oxidation product. The amoximation reaction can be carried out as described in patents US 4794198 and EP 496385.

 Examples of olefins that can be epoxidized by the method of the present invention are: ethylene, propylene, allyl chloride, butenes, pentenes, hexenes, isoprene, cyclooctene and cyclohexene. In particular, the epoxidation of ethylene and propylene can be carried out as described, for example, in patent EF 100119.

 Examples of nitrogen-containing compounds that can be oxidized by a catalyst activated by the method of the present invention can be selected from ammonia and secondary amines.

 The oxidation of these compounds can be carried out in accordance with the descriptions of US patents 5320819 and 4918194.

 The catalyst activated by the method of the present invention can be used in a continuous process without significantly reducing its activity and selectivity.

 The following examples, which are intended to illustrate the present invention in General terms, should not be construed as limiting the scope of this invention.

Example 1. 3.0 g (1.43 mmol Ti) of TS-I catalyst (Enichem, Ti = 2.29 wt.%) And 0.11 g of NH ₄ HF ₂ (Fluka; average titer of 92.5%) in 35 ml of water, which corresponds to a molar ratio F / Ti = 2.5, is loaded into a 100 ml glass flask equipped with a mechanical stirrer, reflux condenser, thermometer and thermostat with oil recirculation. The aqueous suspension of the catalyst with mechanical stirring is heated to 60 ^o C. Then add 1.6 ml of H ₂ O ₂ 30% concentration by weight (C. Erba; density 1,122 g / ml at 20 ^o C, which corresponds to a molar ratio of H ₂ O ₂ / Ti = 11, and the suspension was continued to mix at 60 ^° C. for 4 hours After cooling, the solid precipitate was separated from the mother liquor (pH 4.3) by filtration through a porous filter, then washed several times with deionized water and finally with acetone. under vacuum at 40 ^o C for 8 hours and then at swift STI heating 50 ^o / hr was subjected to heat treatment in air at 550 ^o C for 4 hours. The titer of the activated catalyst is 1,49% Ti. The weight of the solubilized titanium content is 35%.

Examples 2-5. Carry out the same procedure as in example 1, but the activation is carried out at 80 ^o C for 4 hours and at different ratios of reagents. The results are shown in table. 1.

Example 6. The reaction is carried out as described in example 1, but using 0.112 g of NH ₄ F (Fluka; titer 98%), which corresponds to a molar ratio F / Ti = 2.07. The aqueous suspension is heated to 80 ^o C and then add 1.6 ml of H ₂ O ₂ 30 wt.% Concentration (which corresponds to the ratio of H ₂ O ₂ / Ti = 11.0). The suspension is maintained with stirring at 80 ^{° for} 4 hours and then act as in Example 1. The titer of the catalyst is 1.57% Ti. The value of solubilized titanium corresponds to 31.6%.

Example 7. The experiment is carried out in the same way as described in example 1, but using 0.55 g of NH ₄ F in 35 ml of deionized water, which corresponds to a molar ratio F / Ti = 1.02. 1.6 ml of H ₂ O ₂ , 30 wt.% Concentration (molar ratio of H ₂ O ₂ / Ti = 11.0) are added to the suspension heated to 60 ^° C; the temperature of 60 ^o C support for 4 hours, then follow the procedure described in example 1. Catalyst titer: 1.85% Ti. The solubilized titanium content is 19%.

 Example 8. The experiment is carried out as described in example 7, but with a molar ratio F / Ti = 2.82. Activated catalyst titer = 1.85% Ti. The solubilized titanium content is 19%.

 Example 9. Carry out the same procedure as described in example 1, but using a titanium-containing silicalite (TS-I; EniChem) with a titer equal to 2.11% Ti. The activated catalyst has a titer of 1.32% Ti. The solubilized titanium content is 37% by weight.

 Example 10. The same procedure is carried out as described in example 6, but using titanium-containing silicalite (TS-I, EniChem) with a titer equal to 2.11% Ti. The titer of activated catalyst is 1.34% Ti. The content of solubilized Ti 37 wt.%.

 Example 11. The same procedure is carried out as described in example 1, but using titanium-containing silicalite (TS-I, EniChem) with a titer equal to 1.5% Ti. Activated catalyst titer = 1.29% Ti. The solubilized titanium content is 14% by weight.

 Example 12. The same procedure is carried out as described in example 1, but using a solution of 0.72 mol of hydrofluoric acid (HF), which corresponds to a molar ratio F / Ti = 0.5. The same procedure is carried out as in Example 1. The titer of the activated catalyst is 1.72 Ti. The solubilized titanium content is 25% by weight.

Example 13. 3.0 g of TS-I of Example I (Ti = 2.29 wt.%) Was suspended in a solution of 0.77 mmol of hydrobromic acid, which corresponds to a molar ratio F / Ti = 0.5. The pH of the solution was adjusted to 4.7 with NH ₄ OH solution. The following procedure follows as in Example 1. The titer of activated catalyst 0.82% Ti. The solubilized titanium content is 64%.

Example 14. The same procedure is carried out as described in example 1, but using a solution of 0.159 mmol AlF ₃ · 3H ₂ O (Fluka; titer ≥ 97%), which corresponds to a molar ratio F / Ti = 0.33. Activated catalyst titer 2.23% Ti. The solubilized titanium content is 2.6%.

Example 15. 3.0 g of TS-I of example 1 is suspended in a solution of 0.24 mmol of hexafluorosilicic acid (H ₂ SiF ₆ ) in 35 ml of deionized water (molar ratio F / Ti = 1.01). The same procedure is carried out as in Example 1. The titer of activated catalyst is 2.14% Ti. The solubilized titanium content is 6.4%.

 Example 16

12.9 g (5.68 mmol Ti) of TS-I catalyst (EniChem, Ti = 2.11 wt.%) And 0.23 NH ₄ F in 140 ml of water, which corresponds to a molar ratio F / Ti = 1.09 were placed in a 100 ml glass flask equipped with a mechanical stirrer, reflux condenser, thermometer and oil thermostat.

The aqueous suspension of the catalyst is heated to 60 ^o C with mechanical stirring. Then add 6.4 ml of H ₂ O ₂ 30% by weight, which corresponds to a molar ratio of H ₂ O ₂ / Ti = 11, and the suspension is continued to mix for another 4 hours at 60 ^o C.

After cooling, the solid phase is separated from the mother liquor (pH 4.3) by filtration through a porous filter and then washed several times with deionized water, and finally with acetone. Then the catalyst is dried under vacuum at 40 ^o C for 8 hours, and then subjected to heat treatment with air at 550 ^o C for 4 hours with a heating rate of 50 ^o C / hour. The activated catalyst has a Ti titer of 1.74% by weight. The content of solubilized titanium corresponds to 17.5 wt.%.

 Example 17. The synthesis of phenol from benzene.

The benzene hydroxylation reaction is carried out in a flat-bottomed glass reactor with a capacity of 30 ml, equipped with a jacket and a magnetic stirrer, an inlet for reagents, a temperature controller and a reflux condenser cooled to 0 ^° C with a thermocryostat with circulating organosilicon oil. The H ₂ O ₂ solution is metered through an appropriate graduated dropping funnel equipped with a control valve.

7.04 g of benzene (titer 93.5%, Fluka) (90 mmol), 0.7 g of the activated catalyst described in Example 1 (corresponding to 0.22 mmol of Ti) and 15 g of sulfolane (Aldrich, titer 99%) are placed into a reactor filled with nitrogen. The temperature of the mixture was brought to 80 ^o C.

Then, after 2 hours, 1.04 g (9 mmol H ₂ O ₂ ) of an aqueous solution of H ₂ O _{2 was} added at 33% volume / weight, concentration (Rudipont, Reagent Grade, density = 1.11 at 20 ^° C.).

15 minutes after establishing a constant temperature, the reaction mixture was cooled to 20 ^° C with stirring. The catalyst was separated by filtration through a glass porous filter in a nitrogen atmosphere and washed several times with acetonitrile (titer 99.9%, C. Erba, Reagenti RS).

The solution was analyzed by Shimadzu SCL-6A HPLC (LiChrospher 100 PP-18.5 mm cone-shaped column at 40 ^° C., which is controlled by a Merck thermostat) using acetonitrile and an aqueous solution of H ₃ PO ₄ 0.01 molarity as eluents. Analysis of the reaction product yielded the following results: benzene (C1) conversion 6.2% (in moles), phenol yield (YI) 6.2% (in moles), phenol selectivity (SI) 100% (in moles), turnover in hour (TON) = 9.52 (mol / Ti • hour mol).

 HPLC analysis revealed no reaction products other than phenol.

 Example 18 (comparative). The reaction is carried out under the same conditions as in example 17, using the same amount of the corresponding unactivated catalyst.

 The analysis of the reaction product gave the following results: benzene (01) conversion 7.1% (in moles), phenol yield (YI) 6.4% (in moles), phenol selectivity (SI) 90% (in moles), turnover in hour (TON) = 7.49 (mol / T • hour mol).

 HPLC analysis showed the formation of dehydroxylated products such as catechol and hydroquinone.

 Examples 19-22. The reaction is carried out as described in example 17, using catalysts activated as described in examples 2-5. The results are shown in table 2.

 Examples 23-25. The benzene hydroxylation reaction is carried out under the conditions of example 17 using the catalysts of examples 6,7 and 8. The results are shown in table 3.

 Example 26

 The benzene hydroxylation reaction is carried out under the conditions of example 17 using the same weight amount of catalyst activated in example 9. The following results were obtained: benzene conversion (C1) = 5.8% (in mmoles), phenol yield (YI) = 5.8% (in mmoles), phenol selectivity (SI) = 100%, TON = 11.01 (mol / Ti • hour mol).

 Example 27 (comparative).

 The reaction is carried out under the same conditions as in example 26, but using the same amount of the corresponding inactive catalyst (Ti = 2.11%).

 The following results were obtained: benzene conversion (CI) = 5.9% (in mmoles), phenol yield (YI) = 5.5% (in mmoles), phenol selectivity (SI) = 93.8%, TON = 6, 51 (mol / Ti • hour mol).

 Example 28. The reaction is carried out under the same conditions as in example 17, using the same weight amount of catalyst activated in example 11.

 The following results were obtained: benzene conversion (C1) = 5.0% (in mmoles), phenol yield (YI) = 5.0% (in mmoles), phenol selectivity (SI) = 100%, - TON = 10.43 (mol / Ti • hour mol).

 Example 29 (comparative). The reaction is carried out as described in example 28, using the same amount of the corresponding inactive catalyst (Ti = 1.50%).

 The following results were obtained: benzene conversion (C1) = 4.4% (in mmoles), phenol yield (YI) = 4.2% (in mmoles), phenol selectivity (SI) = 95.7%, TON = 7, 68 (mol / Ti • hour mol).

 Example 30-33. The benzene hydroxylation reaction is carried out under the conditions of example 17, but using the catalysts of examples 12-15. The results are shown in table 4.

 Examples 34-35. Perform the same procedure as in example 17, but the hydroxylation is carried out in acetonitrile. The results are shown in table 5.

 Examples 36-37. The reaction is carried out as described in example 17, but instead of benzene, an equimolar amount of phenol (90 mol) is used. The results are shown in table 6.

Examples 38-41 (comparative). 3.25 g (1.43 mmol) of TS-I (titer of 2.11% Ti) are suspended in 35 mg of a 0.5N solution of the following acids: HCl, H ₂ SO ₄ , H ₃ PO ₄ , HNO ₃ . After heating to 60 ^° C., 1.6 ml of H ₂ O _{2 of} 30% by weight concentration was added and the suspension was stirred at 60 ^° C. for 4 hours.

After cooling, the solid phase is separated from the mother liquor (pH 4.3) by filtration through a porous filter and then washed several times with deionized water, and finally with acetone. After that, the catalyst is dried under vacuum at 40 ^o C for 8 hours and then subjected to heat treatment with air at 550 ^o C for 8 hours with a heating rate of 50 ^o C / hour.

The activated catalysts are used for the hydroxylation of benzene as described in example 17. The results are shown in table 7 in comparison with the results obtained using the catalyst activated with NH ₄ HF ₂ in example 2 6 and the non-activated catalyst in example 27.

 Treatment with acids with pKa ≤ 5 does not significantly affect selectivity.

Examples 42-44. The reaction is carried out as described in example 26, but at different molar ratios of H ₂ O ₂ / benzene. The results are shown in table 8.

Examples 45-47. The reaction is carried out as described in example 27, but at different molar ratios of H ₂ O ₂ / benzene. The results are shown in table 9.

Example 48. Amoximation of cyclohexanone
0.610 g (which corresponds to 0.17 mmol Ti) of the activated catalyst according to example 9 (containing 1.32% Ti), 25 ml of an aqueous solution of ammonia (15% by weight, 0.21 mol), 25 ml of tert-butanol and 9, 84 (0.10 mmol) of cyclohexanone are loaded into a 100 ml glass reactor equipped with a stirrer and a heating jacket, pre-filled with an inert gas (helium).

The suspension is heated to 78 ^° C and 11.7 g of an aqueous solution of hydrogen peroxide with a concentration of 30.43 wt.% Are fed into it with stirring for 50 minutes. At the end of the reaction, the suspension is filtered and analyzed by gas chromatography. The results show: cyclohexanone conversion 97.5%, oxime yield 90.5%, oxime selectivity (relative to cyclohexanone converted) 92.9%, yield per hydrogen peroxide 86.6%, catalyst revolution per hour 635 (moles oxime / mole Ti • hour).

 Example 49 (comparative). The reaction is carried out under the same conditions as in Example 48 using 0.39 g (0.17 mmol Ti) of the corresponding inactive catalyst (2.11 wt.% Ti).

The analysis of the reaction product gave the following results: cyclohexanone conversion 68.8% in moles, oxime selectivity 81.0%, oxime yield 55.7%, yield per hydrogen peroxide 52.4%, hourly revolution 387 (moles oxime / Ti • hour of moles)
Example 50 (comparative). The reaction is carried out under the same conditions as in example 48, using 0.59 g (0.17 mmol Ti) of the corresponding inactive catalyst having a titer of Ti (1.38 wt.%), Similar to the titer of the activated catalyst of example 9.

 Analysis of the reaction product yielded the following results: cyclohexanone conversion 68.2% in moles, oxime selectivity 76.1%, oxime yield 51.9%, yield per hydrogen peroxide 49.4%, hourly revolution 369 (moles oxime / Ti • hour of moles).

 Example 51. The reaction is carried out under the same conditions as in example 48, using 0.59 g (0.17 mmol) of an activated catalyst having a Ti titer of 1.34 wt.%, Similar to the titer of the activated catalyst of example 10.

 The analysis of the reaction product gave the following results: cyclohexanone conversion of 85.5% in moles, oxime selectivity of 90.5%, oxime yield of 77.5%, yield per hydrogen peroxide of 71.4%, hourly revolution of 543 (moles of oxime / Ti • hour of moles).

Example 52. The reaction is carried out under the same conditions as in example 48 using an equivalent amount of activated catalyst of 0.17 mmol in example 16 (Ti titer 1.74 wt.%)
The analysis of the reaction product gave the following results: cyclohexanone conversion 73.8% in moles, oxime selectivity 85.7%, oxime yield 63.3%, yield per hydrogen peroxide 58.2%, hourly revolution 436 (moles oxime / Ti • hour of moles).

 Example 53 (comparative). The reaction is carried out under the same conditions as in example 48, using an equivalent amount of activated catalyst of 0.17 mmol Ti according to example 39.

 Analysis of the reaction product gave the following results: cyclohexanone conversion 68.3% in moles, oxime selectivity 76.3%, oxime yield 52.2%, yield calculated on hydrogen peroxide 50.0%, hourly rotation 360 (moles oxime / Ti • hour of moles).

 Example 54. Epoxidation of propylene.

 375 g of a methanol / water mixture (weight ratio 50/1) and 2.71 g (0.75 mmol Ti) of the activated catalyst of Example 9 are loaded into a 1 liter glass reactor equipped with a mechanical stirrer and a heating jacket and arranged in such a way that liquid samples are taken at any given time.

The contents of the reactor are mixed at 800 rpm, heated to 40 ^o C, propylene is fed into the reactor under a pressure of 4 atm. 28.5 g of H ₂ O ₂ , which corresponds to 48.5% by weight, are added over 30 s, and the mixture is allowed to react for 150 minutes. The temperature of 40 ^o C support using an external jacket of the reactor, and the coil located inside is connected to the cryostat. A pressure of 4 atm is maintained, restoring the consumption of propylene. 30 minutes after the addition of hydrogen peroxide, a sample was taken from the reaction solution and analyzed by gas chromatography. Receive: conversion of hydrogen peroxide -94% and selectivity for propylene oxide - 89%.

 Example 55. The oxidation of ammonia. 0.762 g (corresponding to 0.21 mmol Ti) of the activated catalyst of Example 9, 25 ml of an aqueous solution of ammonia (at 15 wt.%) And 25 ml of tertbutanol are charged in an inert atmosphere in a 100 ml jacketed glass reactor equipped with a magnetic stirrer.

The suspension is heated to 70 ^° C. and with stirring for 17 minutes. 1.18 g of an aqueous solution of H ₂ O ₂ are supplied at 30.97% by weight. At the end of the reaction, the suspension is filtered and hydroxylamine is obtained in an amount of 52.7% based on H ₂ O ₂ . The hourly turnover of the catalyst is 99 (mol of hydroxylamine / Ti • hour mol).

Example 56 (comparative). The reaction is carried out under the same conditions as in Example 55, using 0.48 g (which corresponds to 0.21 mmol Ti) of the corresponding inactive catalyst (2.11% Ti) of Example 9. At the end of the reaction, hydroxylamine is obtained with a yield of 49.5 % calculated on H ₂ O ₂ . The hourly turnover of the catalyst is 88 (mol of hydroxylamine / Ti • hour mol).

Claims (33)

1. The method of activation of titanium-containing silicalite of General formula (I)
xTiO ₂ • (1-x) SiO ₂ ,
where x = 0.0001 - 0.04,
by treating it in an aqueous medium with hydrogen peroxide, characterized in that the treatment is carried out in the presence of precursors of fluoride ions or fluorine-containing anions.  2. The method according to claim 1, characterized in that the titanium-containing silicalite of formula (I) is in the form of microspheres.  3. The method according to p. 1, characterized in that in the titanium-containing silicalite of the formula (I), part of the titanium is replaced by other metals selected from boron, aluminum, iron or gallium. 4. The method according to claim 1, characterized in that the fluoride ion precursors are selected from hydrofluoric acid, ammonium fluorides, alkali metal fluorides, for example NaF, KF, LiF, KHF ₂ , or water soluble metals, for example AlF ₃ • 3H ₂ O, or inorganic fluorine derivatives, soluble in water in acid form, such as hydrofluoric acid, borofluoric acid and hexafluorophosphoric acid or in salt form with NH ₄ OH.  5. The method according to claim 4, characterized in that the precursors of fluoride ions are ammonium fluoride and bifluoride.  6. The method according to claim 1, characterized in that the amount of fluorine-containing compound is such that it provides a range of molar ratio F / Ti of 0.5 to 3.0.  7. The method according to claim 6, characterized in that the molar ratio F / Ti varies from 1.0 to 2.5. 8. The method according to claim 1, characterized in that the amount of hydrogen peroxide is such that the molar ratio of H ₂ O ₂ / Ti is in the range of 3.0 - 15.0. 9. The method according to claim 8, characterized in that the molar ratio of H ₂ O ₂ / Ti is in the range of 6 to 12. 10. The method according to claim 1, characterized in that the activation reaction is carried out at 20 - 100 ^o C. 11. The method according to claim 10, characterized in that the temperature is chosen between 60 and 90 ^o C. 12. Titanium-containing silicalite catalyst of General formula (I)
xTiO ₂ • (1-x) SiO ₂ ,
in which x <0.04,
characterized in that it is activated by the method according to claims 1 to 11.  13. The catalyst according to item 12, characterized in that x <0,035.  14. The catalyst according to item 12, characterized in that it has the form of microspheres.  15. The catalyst according to claim 12, characterized in that part of the titanium is replaced by a metal selected from boron, aluminum, iron or gallium.  16. The method of oxidation of an organic substrate selected from aromatic hydrocarbons, olefins and nitrogen-containing compounds, and amoximation of carbonyl-containing compounds with hydrogen peroxide in a solvent medium in the presence of a titanium silicate catalyst (I), characterized in that said catalyst (I) is activated by the method in accordance with paragraphs. 1 - 11.  17. The method according to p. 16, wherein the aromatic hydrocarbons are selected from benzene, toluene, ethylbenzene, chlorobenzene, anisole. 18. The method according to 17, characterized in that the oxidation of benzene to phenol with hydrogen peroxide is carried out in an organic solvent selected from compounds of the general formula (II)

in which R ₁ - R ₄ , identical or different, represent a hydrogen atom or an alkyl group with 1 to 4 carbon atoms. 19. The method according to p. 18, characterized in that in the compound of formula (II) R ₁ - R ₄ is a hydrogen atom.  20. The method according to p. 18, characterized in that the solvent (II) is used in amounts of 10 to 90% by weight of the reaction mixture.  21. The method according to claim 20, characterized in that the solvent (II) is used in amounts of 20 to 80% by weight of the reaction mixture.  22. The method according to p. 18, characterized in that the activated catalyst (I) is used in amounts of 2 to 40 wt.% Calculated on benzene.  23. The method according to item 22, wherein the activated catalyst (I) is used in amounts of 5 to 15 wt.% Calculated on benzene.  24. The method according to p. 18, wherein the benzene is used in amounts of 10 to 80% relative to the weight of the reaction mixture.  25. The method according to p. 24, characterized in that benzene is used in amounts of 30-60% relative to the weight of the reaction mixture.  26. The method according to p. 18, characterized in that the amount of hydrogen peroxide present in the reaction mixture, vary from 5 to 50 mol.% Based on benzene.  27. The method according to p. 26, characterized in that the amount of hydrogen peroxide present in the reaction mixture, vary from 10 to 30 mol.% Based on benzene.  28. The method according to p. 18, characterized in that hydrogen peroxide is used in the form of an aqueous solution with a concentration of 1 to 60 wt.%.  29. The method according to p, characterized in that hydrogen peroxide is used in the form of an aqueous solution with a concentration of 3 to 30 wt.%. 30. The method according to p. 18, characterized in that the reaction is carried out at 50 - 95 ^o C. 31. The method according to p. 30, characterized in that the temperature is in the range of 70 - 85 ^o C.  32. The method according to clause 16, wherein the olefins are selected from ethylene, propylene, allyl chloride, butenes, pentenes, hexenes, cyclooctene, cyclohexene.  33. The method according to clause 16, wherein the nitrogen-containing compound is selected from ammonia and secondary amines.

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