CN104874419A - Titanium silicalite molecular sieve catalyst and application of titanium silicalite molecular sieve in cyclohexanone ammoximation - Google Patents

Abstract

The invention provides a titanium-silicon molecular sieve catalyst and its application in the ammoximation of cyclohexanone. Ethyl orthosilicate and tetrabutyl titanate are hydrolyzed in an aqueous solution of tetrapropyl ammonium hydroxide, crystallized and Calcination to obtain titanium-silicon molecular sieve, and then use trichlorooctadecylsilane to modify, using cyclohexanone, hydrogen peroxide, and ammonia water as the basic raw materials, without adding organic solvents, by adjusting the surface wettability of the catalyst titanium-silicon molecular sieve, Make it have the functions of solid emulsifier and catalyst, build a stable emulsion system with the reaction materials, and efficiently catalyze the synthesis of cyclohexanone oxime. The present invention does not use any organic solvent, avoids the problem of solvent separation and recovery in the production of cyclohexanone oxime by widely using organic solvents such as tert-butanol, facilitates the separation of products, reduces production costs, and increases profits.

Description

A kind of titanium silicon molecular sieve catalyst and its application in cyclohexanone ammoximation

technical field

The invention relates to the technical field of preparation of cyclohexanone oxime, more specifically, relates to a titanium silicon molecular sieve catalyst and its application in cyclohexanone ammoximation.

Background technique

Cyclohexanone Oxime is a white prismatic crystal with a melting point of 89-90°C, a boiling point of 206-210°C, and a relative density of 1.1g/cm ³ . It is soluble in water, ethanol, ether, and methanol. The molecular formula is C ₆ H ₁₁ NO, and the chemical formula is:

Cyclohexanone oxime is an important intermediate in the production of caprolactam, and caprolactam is one of the important organic raw materials. With the development of the chemical fiber industry and the development and expansion of civil and industrial applications of nylon-6, the industrial production of cyclohexanone oxime is increasingly expanding. At present, cyclohexanone oxime is mainly synthesized in industry through multi-step methods, such as the redox method of cyclohexanone hydroxylamine route, hydroxylamine sulfate method and hydroxylamine phosphoric acid method, etc. These processes need to use raw materials produced by "three wastes" in the production process, and a large amount of low-value ammonium sulfate by-products are associated. With the increasing demand of caprolactam, improving the existing production process has become an important research topic of concern.

So far, the most noticeable improvement method is the cyclohexanone oximation process developed by Italy's Enichem Company, which uses cyclohexanone, ammonia and hydrogen peroxide as raw materials, under the catalysis of titanium silicon molecular sieve TS-1 Synthesis of cyclohexanone oxime under atmospheric pressure. The process has very few by-products, can basically overcome the shortcomings of traditional processes, and is expected to achieve zero emissions and achieve the purpose of clean production. Chinese patent CN103382163A discloses a preparation method of cyclohexanone oxime. In the presence of catalyst and water, cyclohexanone, ammonia and hydrogen peroxide are contacted and reacted in an organic solvent, wherein the organic solvent is low-carbon hydrocarbon and low-carbon Alcohol mixed solvent. The method can increase the yield of the product cyclohexanone oxime, but there are difficulties in the recovery of the mixed solvent and the separation and purification of the product, and the cost is high. Chinese patent CN103360279A discloses a method for preparing cyclohexanone oxime by ammoximation of cyclohexanone, in which reaction materials such as cyclohexanone, hydrogen peroxide, ammonia and solvent are contacted with a titanium silicon molecular sieve with a mass fraction of 1-10% 60-100 minutes, then react at 0.6MPa, 60-90°C. The mixed contact before the reaction can improve the reaction effect, but the hydrogen peroxide and ammonia will be decomposed ineffectively at the same time, resulting in waste of reactants and increase in cost. Chinese patent CN103288677A discloses a method for preparing cyclohexanone oxime from cyclohexanone. In the presence of Ti-MWW molecular sieve and nano-carbon fiber composite catalyst and water, cyclohexanone, hydrogen peroxide and ammonia are directly reacted. Instead of organic solvents, however, the synthesis steps of MWW-containing titanium-silicon molecular sieves are cumbersome, the ratio of raw materials is narrow, and a large amount of template agent and boric acid are consumed, resulting in high costs.

Contents of the invention

The purpose of the present invention is to overcome the deficiencies in the prior art, provide a kind of titanium silicon molecular sieve catalyst and its application in cyclohexanone ammoximation, use any organic solvent, take cyclohexanone as raw material, hydrogen peroxide and ammoniacal liquor as The reaction raw material and the catalyst have both the functions of a solid emulsifier, and a stable Pickering emulsion system is constructed with the reaction raw material, in which cyclohexanone oxime is efficiently synthesized, the product is separated easily, and the alkali-thermal stability of the hydrophobic catalyst is improved.

The purpose of the present invention is achieved through the following technical solutions:

Titanium silicate molecular sieve catalyst is prepared according to the following steps:

Step 1: hydrolyzing ethyl orthosilicate and tetrabutyl titanate in an aqueous solution of tetrapropylammonium hydroxide for 0.5-4 hours, the hydrolysis reaction temperature is 20-30 degrees Celsius, heating and evaporating the alcohol generated by the hydrolysis reaction to obtain Colloid, the generated colloid is crystallized in a crystallization kettle, the crystallization temperature is 150-200°C, and the crystallization time is 20-30h. The crystallized colloid is taken out, filtered, washed, and dried, and then placed in 400 Calcined at -600°C for 1-5 hours to obtain titanium-silicon molecular sieves;

In said step 1, utilize ethyl orthosilicate to provide silicon element, utilize tetrabutyl titanate to provide titanium element, in the hydrolysis reaction, the molar ratio of silicon element, titanium element, tetrapropyl ammonium hydroxide and water is 1: (0.01-0.03): (0.1-0.5): (20-60).

In the step 1, after the hydrolysis reaction, the temperature is raised to 50-70 degrees Celsius to heat and evaporate the alcohol in the hydrolysis reaction to obtain the colloid.

In the step 1, the hydrolysis reaction time is preferably 1-2h, the crystallization temperature is preferably 160-180°C, the crystallization time is preferably 24-28h, the calcination temperature is preferably 500-600°C, and the calcination temperature is preferably 500-600°C. The time is preferably 1-3h.

Step 2, modification of the titanium-silicon molecular sieve: put the titanium-silicon molecular sieve into the reaction vessel, add toluene as a solvent into the above-mentioned reaction vessel, and stir the above-mentioned reaction vessel at a stirring speed of 800-1200 rpm. , Add the toluene solution of trichlorooctadecylsilane dropwise to the above reaction vessel at 20-25°C, the time for adding the toluene solution of trichlorooctadecylsilane is 10-60min, after the dropwise addition is completed, continue Stir the reaction for 8-12 hours. After the reaction is completed, centrifuge the above reaction solution, take the solid obtained after centrifugation, and wash the above solid with acetone for 2-5 times, and then put the above solid in an oven at 60-100°C for 10-14 hours. , to obtain a modified titanium-silicon molecular sieve, that is, a titanium-silicon molecular sieve catalyst;

In the step 2, the volume fraction of the toluene solution of trichlorooctadecylsilane is equal to the mass fraction of the titanium silicon molecular sieve, the volume fraction is ml, and the mass fraction is g.

In said step 2, in the toluene solution of trichlorooctadecylsilane, the ratio of the mass fraction of trichlorooctadecylsilane to the volume fraction of toluene is (0.1-0.5): 10, the volume fraction In ml, parts by mass in g.

In the step 2, the stirring speed is preferably 1000-1200 rpm, the dropping time is preferably 30-40min, the stirring reaction time is preferably 10-12h, and the solid is washed 3 times with acetone. Drying, the drying temperature is preferably 80-100°C, and the drying time is preferably 10-12h.

The titanium-silicon molecular sieve catalyst of the present invention is in the shape of an ellipsoid with a major semi-axis of 100-150 nm and a minor semi-axis of 50-75 nm, preferably a major semi-axis of 100-120 nm and a minor semi-axis of 60-75 nm.

The appearance of the titanium-silicon molecular sieve catalyst of the present invention was characterized by using a field emission scanning electron microscope model S-4800 from Hitachi, Japan, as shown in Figure 1, the SEM image of the titanium-silicon molecular sieve. It can be seen from the figure that the titanium-silicon molecular sieve is in the shape of an ellipsoid with a major semi-axis of 100-150 nm and a minor semi-axis of 50-75 nm. Using the X-ray diffractometer of Bruker AXS Co., Ltd., Germany, the model is D8-Focus, as shown in Figure 2, that is, the X-ray diffraction pattern of titanium-silicon molecular sieves. The star-shaped mark in the figure is the characteristic peak of the MFI topology, and the ellipse The shape mark is the skeleton titanium peak. Utilize Bruker Fourier infrared spectrometer Co., Ltd. of Germany, the Fourier infrared spectrometer that the model is TENSOR27 obtains the infrared spectrogram of the titanium-silicon molecular sieve of step 1 and the modified titanium-silicon molecular sieve of step 2, as shown in accompanying drawing 3, after modification , new absorption peaks appeared at 2853.15cm ^-1 and 2923.11cm ^-1 , which proved that the alkyl functional group was connected to the titanium silicon molecular sieve.

For the titanium-silicon molecular sieve of the present invention, utilize German dataphysics company, the contact angle meter measuring data that model is OCA15EC is as follows: the molecular sieve before modification (being the titanium-silicon molecular sieve prepared in step 1) contact angle is 18-20 (such as 19.7 °), the contact angle of the modified molecular sieve (ie the modified molecular sieve prepared in step 2) can reach 90-95° (for example, 91.3°). Measured by the NOVA 2000 series of Quantachrome Instruments Company in the United States, the modified molecular sieve has a part of the pore size change compared with the unmodified molecular sieve because the alkyl group is linked to the titanium-silicon molecular sieve. The specific surface area of the modified molecular sieve is 400-460m ² /g, the pore volume is 0.35-0.4mL/g, and the average pore diameter is 1.5-2.5nm.

Utilizing the application of the titanium-silicon molecular sieve catalyst in the ammoximation of cyclohexanone, the titanium-silicon molecular sieve catalyst is used as a catalyst and a solid emulsifier, so that the reaction materials form a stable emulsion system for reaction.

Cyclohexanone, titanium silicon molecular sieves and deionized water are stirred in a reactor to form a stable emulsion system (such as Pickering emulsion). In the emulsion system, the volume ratio of cyclohexanone and deionized water is 1: 1. The ratio of the mass fraction of titanium silicon molecular sieve to the volume fraction of cyclohexanone is (0.15-0.2): 1; the emulsion system is heated to 60-80 degrees Celsius, and ammonia water is added dropwise to the emulsion system under stirring conditions and hydrogen peroxide, the hydrogen peroxide provides the active ingredient hydrogen peroxide, the ammonia water provides the active ingredient NH ₃ , the molar ratio of cyclohexanone, hydrogen peroxide and NH ₃ is 1: (1-1.5): (1-2), After the dropwise addition, keep the temperature at 60-80 degrees Celsius and continue the reaction for at least 1 hour to obtain the product cyclohexanone oxime.

In the above technical scheme, the mass fraction of the titanium-silicon molecular sieve is measured in g, and the volume fraction of cyclohexanone is measured in ml.

In the above technical scheme, the ratio of the mass fraction of the titanium-silicon molecular sieve to the volume fraction of cyclohexanone is (0.15-0.17): 1.

In the above-mentioned technical scheme, hydrogen peroxide is an aqueous solution of hydrogen peroxide, and the mass percentage of hydrogen peroxide (the mass of hydrogen peroxide/the total mass of hydrogen peroxide and water) is 25-30%; ammoniacal _liquor is an aqueous solution of NH ₃ The mass percentage (NH ₃ mass/NH ₃ and the total mass of water) is 20-25%.

In the above technical scheme, the reaction was continued for 1.5-3 hours after the dropwise addition was completed.

In the above technical scheme, the rate of dropping ammonia water is 0.2-0.3mL/min, and the rate of dropping hydrogen peroxide is 0.2-0.3mL/min. Preferably, the rate of dropping ammonia water is consistent with the rate of dropping hydrogen peroxide.

Using Beifen Rayleigh 3420A gas chromatography (carrier gas flow rate 30mL/min, feed volume 0.2μL, gasification chamber temperature 220°C, detection chamber temperature 250°C, column temperature: initial temperature 90°C, heating rate 8°/min, The final temperature is 150°C and kept for 5 minutes) to detect the reaction result. For the obtained reaction product, tert-butanol was added to make the product into a homogeneous phase for chromatographic sampling measurement, and the volume ratio of cyclohexanone and tert-butanol was 1:6. In the obtained spectrogram 5, at the residence time t=1.501min, tert-butanol peaks; at t=2.671min, cyclohexanone peaks, because cyclohexanone reacts and converts a lot, and there is little left, so the peak is very low ; t=4.958min is the peak of cyclohexanone oxime, indicating that the titanium silicon catalyst of the present invention can be used to prepare cyclohexanone oxime without using tert-butanol.

Compared with the existing preparation method, the present invention has the following beneficial effects: (1) the present invention makes the catalyst have the function of solid emulsifier concurrently by adjusting the surface wettability of titanium silicon molecular sieve, forms stable Pickering emulsion system with reaction raw material and react in it. (2) The present invention does not use any organic solvent to homogenize the reaction system, and there is no problem of solvent separation and recovery. (3) In the present invention, since no solvent is used, the product cyclohexanone oxime is easy to separate. (4) In the present invention, the hydrophobized modified titanium-silicon molecular sieve is more stable in hot alkali.

Description of drawings

Fig. 1 is the SEM picture of the titanium silicon molecular sieve catalyst prepared by the present invention.

Fig. 2 is an XRD pattern of the titanium-silicon molecular sieve catalyst prepared in the present invention.

Fig. 3 is an infrared spectrum diagram of the titanium-silicon molecular sieve prepared by the present invention before and after modification.

Fig. 4 is that titanium silicon molecular sieve of the present invention forms Pickering emulsion with deionized water, wherein, (a) is the Pickering emulsion that untreated catalyst forms as solid emulsifier, (b) (c) is the modified catalyst as Pickering emulsion formed by solid emulsifier.

Fig. 5 is a schematic diagram of gas spectrum detection results of products after cyclohexanone ammoximation reaction using the titanium-silicon molecular sieve catalyst of the present invention.

Detailed ways

The technical solutions of the present invention will be further described below through specific examples.

Example 1

Step 1: Hydrolyze ethyl orthosilicate and tetrabutyl titanate in an aqueous solution of tetrapropylammonium hydroxide for 4 hours, the hydrolysis reaction temperature is 30 degrees Celsius, heat and evaporate the alcohol generated by the hydrolysis reaction to obtain a colloid, and generate The colloid is crystallized in a crystallization kettle, the crystallization temperature is 200°C, and the crystallization time is 30h. The crystallized colloid is taken out, filtered, washed, dried, and then calcined at 600°C for 1h to obtain Titanium-silicon molecular sieve; silicon element is provided by ethyl orthosilicate, and titanium element is provided by tetrabutyl titanate. In the hydrolysis reaction, the molar ratio of silicon element, titanium element, tetrapropylammonium hydroxide and water is 1:0.01 :0.5:60. After the hydrolysis reaction, the temperature was raised to 50 degrees Celsius to heat and evaporate the alcohol in the hydrolysis reaction to obtain a colloid.

Step 2, modification of titanium-silicon molecular sieve: put 10g of titanium-silicon molecular sieve into the reaction vessel, add toluene as a solvent into the above-mentioned reaction vessel, and stir the above-mentioned reaction vessel at a stirring speed of 1200 rpm. Under stirring conditions, Add the toluene solution of trichlorooctadecylsilane (0.125g/10ml) dropwise to the above reaction vessel at 25°C. The time for adding the toluene solution of trichlorooctadecylsilane is 60min. After the addition is complete, Continue to stir and react for 12 hours. After the reaction is completed, centrifuge the above reaction solution, take the solid obtained after centrifugation, wash the above solid with acetone for 5 times, and then put the above solid in an oven at 100°C for 10 hours to obtain a modified titanium silicon molecular sieve. , namely titanium silicate molecular sieve catalyst.

Step 3, stirring cyclohexanone, titanium-silicon molecular sieve and deionized water in a reactor to form a stable emulsion system, in the emulsion system, the volume ratio of cyclohexanone and deionized water is 100ml, titanium-silicon The molecular sieve is 20g; the emulsion system is heated up to 80 degrees Celsius, and ammonia water and hydrogen peroxide are added dropwise to the emulsion system under stirring conditions, the hydrogen peroxide provides the active ingredient hydrogen peroxide, and the ammonia water provides the active ingredient NH ₃ , cyclohexanone 1. The molar ratio of hydrogen peroxide and _NH3 is 1:1.5:1. After the dropwise addition, keep at 80 degrees Celsius and continue to react for 3 hours to obtain the product cyclohexanone oxime. Hydrogen peroxide is an aqueous solution of hydrogen peroxide, and the mass percentage of hydrogen peroxide is 30%; ammonia water is an aqueous solution of NH ₃ , and the mass percentage of NH ₃ is 25%. The speed of adding ammonia water dropwise is 0.2mL/min, and the speed of adding hydrogen peroxide dropwise is 0.2mL/min.

As detected by gas chromatography, the conversion rate of cyclohexanone was 98.50%, and the selectivity of cyclohexanone oxime was 95.22%. Centrifuge the catalyst, add ethanol to recrystallize cyclohexanone oxime, wash and dry to obtain the product cyclohexanone oxime with a purity of 98%.

Example 2

Step 1: hydrolyze ethyl orthosilicate and tetrabutyl titanate in an aqueous solution of tetrapropylammonium hydroxide for 0.5h, the hydrolysis reaction temperature is 20 degrees Celsius, heat and evaporate the alcohol generated by the hydrolysis reaction to obtain a colloid, and The generated colloid is crystallized in a crystallization kettle, the crystallization temperature is 150°C, and the crystallization time is 20h. The crystallized colloid is taken out, filtered, washed, dried, and then calcined at 400°C for 5h, that is Titanium-silicon molecular sieves are obtained; silicon is provided by ethyl orthosilicate, and titanium is provided by tetrabutyl titanate. In the hydrolysis reaction, the molar ratio of silicon, titanium, tetrapropylammonium hydroxide and water is 1: 0.03:0.1:20. After the hydrolysis reaction, the temperature was raised to 70 degrees Celsius to heat and evaporate the alcohol in the hydrolysis reaction to obtain a colloid.

Step 2, modification of titanium-silicon molecular sieve: put 10g of titanium-silicon molecular sieve into the reaction vessel, add toluene as a solvent into the above-mentioned reaction vessel, and stir the above-mentioned reaction vessel at a stirring speed of 800 rpm. Under stirring conditions, Add the toluene solution (0.5g/10ml) of trichlorooctadecylsilane dropwise into the above reaction vessel at 25°C, the time for adding the toluene solution of trichlorooctadecylsilane is 10min, after the dropwise addition is completed, Continue to stir and react for 8 hours. After the reaction is completed, centrifuge the above reaction solution, take the solid obtained after centrifugation, wash the above solid with acetone twice, and then put the above solid in an oven at 60°C for 14 hours to obtain a modified titanium silicon molecular sieve. , namely titanium silicate molecular sieve catalyst.

Step 3, stirring cyclohexanone, titanium-silicon molecular sieve and deionized water in a reactor to form a stable emulsion system, in the emulsion system, the volume ratio of cyclohexanone and deionized water is 100ml, titanium-silicon The molecular sieve is 15g; the emulsion system is heated up to 60 degrees Celsius, and ammonia water and hydrogen peroxide are added dropwise to the emulsion system under stirring conditions, the hydrogen peroxide provides the active ingredient hydrogen peroxide, and the ammonia water provides the active ingredient NH ₃ , cyclohexanone 1. The molar ratio of hydrogen peroxide and _NH3 is 1:1:2. After the dropwise addition, keep at 80 degrees Celsius and continue the reaction for 1.5 hours to obtain the product cyclohexanone oxime. Hydrogen peroxide is an aqueous solution of hydrogen peroxide, and the mass percentage of hydrogen peroxide is 30%; ammonia water is an aqueous solution of NH ₃ , and the mass percentage of NH ₃ is 25%. The speed of adding ammonia water dropwise is 0.3mL/min, and the speed of adding hydrogen peroxide dropwise is 0.3mL/min.

The conversion rate of cyclohexanone was 98% and the selectivity of cyclohexanone oxime was 95.12% through gas chromatography detection. Centrifuge the catalyst, add ethanol to recrystallize cyclohexanone oxime, wash and dry to obtain the product cyclohexanone oxime with a purity of 98.6%.

Example 3

Step 1: Hydrolyze ethyl orthosilicate and tetrabutyl titanate in an aqueous solution of tetrapropylammonium hydroxide for 2 hours, the hydrolysis reaction temperature is 20 degrees Celsius, heat and evaporate the alcohol generated by the hydrolysis reaction to obtain a colloid, and generate The colloid is crystallized in a crystallization kettle, the crystallization temperature is 160°C, and the crystallization time is 24h. The crystallized colloid is taken out, filtered, washed, dried, and then calcined at 600°C for 1h to obtain Titanium-silicon molecular sieve; use ethyl orthosilicate to provide silicon element, and use tetrabutyl titanate to provide titanium element. In the hydrolysis reaction, the molar ratio of silicon element, titanium element, tetrapropylammonium hydroxide and water is 1:0.02 :0.3:40. After the hydrolysis reaction, heat up to 60 degrees Celsius to heat and evaporate the alcohol in the hydrolysis reaction to obtain a colloid.

Step 2, modification of titanium-silicon molecular sieve: put 10g of titanium-silicon molecular sieve into the reaction vessel, add toluene as a solvent into the above-mentioned reaction vessel, and stir the above-mentioned reaction vessel at a stirring speed of 800 rpm. Under stirring conditions, Add the toluene solution of trichlorooctadecylsilane (0.3g/10ml) dropwise to the above reaction vessel at 25°C. The time for adding the toluene solution of trichlorooctadecylsilane is 10min. After the dropwise addition, Continue to stir and react for 8 hours. After the reaction is completed, centrifuge the above reaction solution, take the solid obtained after centrifugation, wash the above solid with acetone twice, and then put the above solid in an oven at 60°C for 14 hours to obtain a modified titanium silicon molecular sieve. , namely titanium silicate molecular sieve catalyst.

Step 3, stirring cyclohexanone, titanium-silicon molecular sieve and deionized water in a reactor to form a stable emulsion system, in the emulsion system, the volume ratio of cyclohexanone and deionized water is 100ml, titanium-silicon The molecular sieve is 16g; the emulsion system is heated up to 60 degrees Celsius, and ammonia water and hydrogen peroxide are added dropwise to the emulsion system under stirring conditions, the hydrogen peroxide provides the active ingredient hydrogen peroxide, and the ammonia water provides the active ingredient NH ₃ , cyclohexanone 1. The molar ratio of hydrogen peroxide and _NH3 is 1:1:2. After the dropwise addition, keep at 80 degrees Celsius and continue the reaction for 1.5 hours to obtain the product cyclohexanone oxime. Hydrogen peroxide is an aqueous solution of hydrogen peroxide, and the mass percentage of hydrogen peroxide is 30%; ammonia water is an aqueous solution of NH ₃ , and the mass percentage of NH ₃ is 25%. The speed of adding ammonia water dropwise is 0.3mL/min, and the speed of adding hydrogen peroxide dropwise is 0.3mL/min.

As detected by gas chromatography, the conversion rate of cyclohexanone was 98.8%, and the selectivity of cyclohexanone oxime was 96.12%. Centrifuge the catalyst, add ethanol to recrystallize cyclohexanone oxime, wash and dry to obtain the product cyclohexanone oxime with a purity of 99.6%.

Example 4

Step 1: Hydrolyze ethyl orthosilicate and tetrabutyl titanate in an aqueous solution of tetrapropylammonium hydroxide for 1 hour, the hydrolysis reaction temperature is 20 degrees Celsius, heat and evaporate the alcohol generated by the hydrolysis reaction to obtain a colloid, and generate The colloid is crystallized in a crystallization kettle, the crystallization temperature is 180°C, and the crystallization time is 28h. The crystallized colloid is taken out, filtered, washed, dried, and calcined at 500°C for 3h to obtain Titanium-silicon molecular sieve; use ethyl orthosilicate to provide silicon element, use tetrabutyl titanate to provide titanium element, in the hydrolysis reaction, the molar ratio of silicon element, titanium element, tetrapropylammonium hydroxide and water is 1:0.03 :0.2:50. After the hydrolysis reaction, the temperature was raised to 70 degrees Celsius to heat and evaporate the alcohol in the hydrolysis reaction to obtain a colloid.

Step 2, modification of titanium-silicon molecular sieve: put 10g of titanium-silicon molecular sieve into the reaction vessel, add toluene as a solvent into the above-mentioned reaction vessel, and stir the above-mentioned reaction vessel at a stirring speed of 800 rpm. Under stirring conditions, Add the toluene solution (0.2g/10ml) of trichlorooctadecylsilane dropwise into the above reaction vessel at 25°C, the time for adding the toluene solution of trichlorooctadecylsilane is 10min, after the dropwise addition is completed, Continue to stir and react for 8 hours. After the reaction is completed, centrifuge the above reaction solution, take the solid obtained after centrifugation, wash the above solid with acetone twice, and then put the above solid in an oven at 60°C for 14 hours to obtain a modified titanium silicon molecular sieve. , namely titanium silicate molecular sieve catalyst.

Step 3, stirring cyclohexanone, titanium-silicon molecular sieve and deionized water in a reactor to form a stable emulsion system, in the emulsion system, the volume ratio of cyclohexanone and deionized water is 100ml, titanium-silicon The molecular sieve is 17g; the emulsion system is heated up to 80 degrees Celsius, and ammonia water and hydrogen peroxide are added dropwise to the emulsion system under stirring conditions, the hydrogen peroxide provides the active ingredient hydrogen peroxide, and the ammonia water provides the active ingredient NH ₃ , cyclohexanone 1. The molar ratio of hydrogen peroxide and _NH3 is 1:1.5:1. After the dropwise addition, keep at 80 degrees Celsius and continue to react for 3 hours to obtain the product cyclohexanone oxime. Hydrogen peroxide is an aqueous solution of hydrogen peroxide, and the mass percentage of hydrogen peroxide is 30%; ammonia water is an aqueous solution of NH ₃ , and the mass percentage of NH ₃ is 25%. The speed of adding ammonia water dropwise is 0.2mL/min, and the speed of adding hydrogen peroxide dropwise is 0.2mL/min.

As detected by gas chromatography, the conversion rate of cyclohexanone was 99%, and the selectivity of cyclohexanone oxime was 97.2%. Centrifuge the catalyst, add ethanol to recrystallize cyclohexanone oxime, wash and dry to obtain the product cyclohexanone oxime with a purity of 99.5%.

The catalyst of the present invention can be prepared by adjusting the process of the preparation method according to the technical scheme of the present invention, and the preparation of cyclohexanone oxime can be realized through the catalyst of the present invention, and a stable emulsion system can be obtained.

The present invention has been described as an example above, and it should be noted that, without departing from the core of the present invention, any simple deformation, modification or other equivalent replacements that can be made by those skilled in the art without creative labor all fall within the scope of this invention. protection scope of the invention.

Claims (9)

1. Titanium-silicon molecular sieve catalyst, characterized in that the titanium-silicon molecular sieve catalyst is an ellipsoidal shape with a major semi-axis of 100-150 nanometers and a minor semi-axis of 50-75 nanometers, with a specific surface area of 400-460 m ² /g, and pore The volume is 0.35-0.4mL/g, the average pore size is 1.5-2.5nm, and it is prepared according to the following steps: Step 1: hydrolyzing ethyl orthosilicate and tetrabutyl titanate in an aqueous solution of tetrapropylammonium hydroxide for 0.5-4 hours, the hydrolysis reaction temperature is 20-30 degrees Celsius, heating and evaporating the alcohol generated by the hydrolysis reaction to obtain Colloid, the generated colloid is crystallized in a crystallization kettle, the crystallization temperature is 150-200°C, and the crystallization time is 20-30h. The crystallized colloid is taken out, filtered, washed, and dried, and then placed in 400 Calcined at -600°C for 1-5 hours to obtain titanium-silicon molecular sieves; in the step 1, use ethyl orthosilicate to provide silicon elements, use tetrabutyl titanate to provide titanium elements, and in the hydrolysis reaction, silicon elements The molar ratio of titanium, tetrapropylammonium hydroxide and water is 1: (0.01-0.03): (0.1-0.5): (20-60); Step 2, modification of the titanium-silicon molecular sieve: put the titanium-silicon molecular sieve into the reaction vessel, add toluene as a solvent into the above-mentioned reaction vessel, and stir the above-mentioned reaction vessel at a stirring speed of 800-1200 rpm. , Add the toluene solution of trichlorooctadecylsilane dropwise to the above reaction vessel at 20-25°C, the time for adding the toluene solution of trichlorooctadecylsilane is 10-60min, after the dropwise addition is completed, continue Stir the reaction for 8-12 hours. After the reaction is completed, centrifuge the above reaction solution, take the solid obtained after centrifugation, and wash the above solid with acetone for 2-5 times, and then put the above solid in an oven at 60-100°C for 10-14 hours. , to obtain a modified titanium-silicon molecular sieve, i.e. a titanium-silicon molecular sieve catalyst; in the step 2, the volume fraction of the toluene solution of trichlorooctadecylsilane is equal to the mass fraction of the titanium-silicon molecular sieve, and the trichlorooctadecyl The ratio of parts by mass of silane to parts by volume of toluene is (0.1-0.5):10. 2. The titanium-silicon molecular sieve catalyst according to claim 1, characterized in that, the titanium-silicon molecular sieve catalyst is preferably in the shape of an ellipsoid with a semi-major axis of 100-120 nanometers and a semi-minor axis of 60-75 nanometers. 3. The titanium-silicon molecular sieve catalyst according to claim 1, characterized in that, in said step 1, after the hydrolysis reaction, the temperature is raised to 50-70 degrees Celsius to heat and evaporate the alcohol of the hydrolysis reaction to obtain the colloid; the hydrolysis reaction The preferred time for calcination is 1-2h, the crystallization temperature is preferably 160-180°C, the crystallization time is preferably 24-28h, the calcination temperature is preferably 500-600°C, and the calcination time is preferably 1-3h. 4. The titanium-silicon molecular sieve catalyst according to claim 1, characterized in that, in the step 2, the stirring speed is preferably 1000-1200 revolutions/min, and the dropping time is preferably 30-40min, so The stirring reaction time is preferably 10-12 hours, and the solid is washed with acetone for 3 times before drying. The drying temperature is preferably 80-100° C., and the drying time is preferably 10-12 hours. 5. The application of titanium-silicon molecular sieve catalyst in the ammoximation of cyclohexanone is characterized in that cyclohexanone, titanium-silicon molecular sieve and deionized water are stirred in a reactor to form a stable emulsion system, and in the emulsion system , the volume ratio of the cyclohexanone and deionized water is 1:1, the mass fraction of the titanium silicon molecular sieve and the volume fraction ratio of the cyclohexanone are (0.15-0.2):1; the emulsion system is heated to 60- 80 degrees centigrade, add ammonia water and hydrogen peroxide dropwise to the emulsion system under stirring conditions, the hydrogen peroxide provides the active ingredient hydrogen peroxide, and the ammonia water provides the active ingredient NH ₃ , the moles of cyclohexanone, hydrogen peroxide and NH ₃ The ratio is 1: (1-1.5): (1-2). After the dropwise addition, keep at 60-80 degrees Celsius and continue the reaction for at least 1 hour to obtain the product cyclohexanone oxime. 6. the application of titanium-silicon molecular sieve catalyst in cyclohexanone ammoximation according to claim 5, is characterized in that, the mass fraction of described titanium-silicon molecular sieve and the volume fraction ratio of cyclohexanone are (0.15- 0.17): 1, the mass fraction of titanium silicon molecular sieve is measured in g, and the volume fraction of cyclohexanone is measured in ml. 7. the application of titanium-silicon molecular sieve catalyst according to claim 5 in the ammoximation of cyclohexanone is characterized in that hydrogen peroxide is an aqueous solution of hydrogen peroxide, and the mass percent of hydrogen peroxide is 25-30%; ammoniacal liquor is Aqueous solution of NH ₃ , the mass percentage of NH ₃ is 20-25%. 8. The application of the titanium-silicon molecular sieve catalyst in the ammoximation of cyclohexanone according to claim 5, characterized in that the reaction is continued for 1.5-3 hours after the dropwise addition is completed. 9. The application of the titanium-silicon molecular sieve catalyst according to claim 5 in the ammoximation of cyclohexanone, characterized in that the dropwise addition of ammoniacal liquor is 0.2-0.3mL/min, and the dropwise addition of hydrogen peroxide is 0.2mL/min. -0.3mL/min, preferably dropwise adding ammoniacal liquor is consistent with the dropwise adding rate of hydrogen peroxide.