Process for the extraction of 2,3-dimethyl-2,3-dinitrobutane from deactivated titanium silicalite catalyst

Abstract

The application discloses a method for extracting 2,3-dimethyl-2,3-dinitrobutane from deactivated titanium silicalite molecular sieve catalyst, and a stirred tank method comprises the following steps: A1, raw material deactivated titanium silicalite molecular sieve catalyst is added into a stirred tank, then a solvent is added, stirring is carried out in the stirred tank with the raw material and the solvent, and heating is carried out at the same time for 1-3 hours, then a mixed solution I containing by-products is obtained; A2, the mixed solution I containing by-products in the step A1 is subjected to hot filtration, and a mixed solution II is obtained; A3, the mixed solution II in the step A2 is subjected to low-temperature evaporation concentration, and a concentrated solution III is obtained; A4, the stirred tank concentrated solution III obtained in the step A3 is subjected to cooling crystallization, then second solid-liquid separation is carried out, solid is obtained and is subjected to washing; A5, the solid obtained in the step A4 is subjected to vacuum drying, and 2,3-dimethyl-2,3-dinitrobutane is obtained. The application realizes product recovery through a solvent purification method, and improves economic benefits.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of chemical purification, in particular to a method for extracting 2,3-dimethyl-2,3-dinitrobutane from deactivated titanium silicalite catalyst. BACKGROUND

[0002] 2,3-dimethyl-2,3-dinitrobutane is a chemical intermediate, mainly used for explosive tracer, and is an important raw material for synthesizing 2-substituted-1,3-dioxane-4,4,5,5-tetramethyl imidazoline and various ammonia nitrogen radical main bodies of molecular magnets, and has a relatively important role in medicine and magnetic new materials. Its synthesis process mainly includes oxidation method, condensation method and ammonoximation method. Among them, the oxidation method and the condensation method mostly directly use 2-nitropropane as raw material. SHECHTER H and KAPLAN R B use ammonium persulfate, hydrogen peroxide, silver nitrate and other oxidants to oxidize 2-nitropropane to generate 2,3-dimethyl-2,3-dinitrobutane; Hien-Quan Do et al. use 2-nitropropane as raw material and copper chloride as catalyst to synthesize DMNB in the presence of DBU (1,8-diazabicycloundec-7-ene base) and O2; orin and Sello use sodium hydride to generate carbon anion from 2-nitropropane, and then synthesize 2,3-dimethyl-2,3-dinitrobutane under the oxidation of cerium ammonium nitrate, but this method uses dangerous chemicals such as sodium hydride; Seigle and Hass first reported the condensation method: in an ethanol system, 2-nitropropane sodium salt and halogenated 2-nitropropane react to generate 2,3-dimethyl-2,3-dinitrobutane, and the yield of iodide is highest at 43%. In summary, the oxidation method or the condensation method mostly has complex process and harsh reaction conditions, and involves raw materials that are not easy to obtain.

[0003] The ammonoximation method mainly uses titanium silicalite as catalyst to obtain the oxidative coupling product 2,3-dimethyl-2,3-dinitrobutane through oxidation and deoximation reaction of acetone oxime in alkaline environment, or uses acetone as raw material to synthesize by controlling the proportion of ammonia and hydrogen peroxide. Patent CN202210146239.6 uses acetone as raw material to prepare 2,3-dimethyl-2,3-dinitrobutane under the action of modified TS-1 catalyst, and the molar yield of the product is highest at 11.4%.

[0004] Titanium silicalite is an important catalytic oxidation catalyst, and the green catalytic oxidation system composed of titanium silicalite and hydrogen peroxide is widely used in processes such as aromatic hydroxylation, ketone aminooxidation, and olefin epoxidation. Patent CN202211374526.7 uses modified titanium silicalite as a catalyst to prepare 2-nitropropane, and patent CN202011509993.7 discloses a titanium silicalite catalyst for producing 2-nitropropane. Patents CN201610507953.6 and CN201610587135.1 disclose a method for preparing 2-nitropropane and co-producing acetone oxime using titanium silicalite as a catalyst. In the process of synthesizing 2-nitropropane from acetone, the catalyst has high activity at the beginning of the reaction. By adjusting the raw materials and reaction conditions, the generation of byproduct 2,3-dimethyl-2,3-dinitrobutane can be inhibited to some extent. When the titanium silicalite catalyst is used to the end, the active sites of the catalyst are gradually occupied by byproducts, leading to a sharp decrease in catalytic activity and an increase in the yield of byproduct 2,3-dimethyl-2,3-dinitrobutane. It is found through actual use that the content of various impurities adsorbed in the deactivated titanium silicalite catalyst is about 8-10% of the mass of the catalyst, and 2,3-dimethyl-2,3-dinitrobutane accounts for 95-96% of the impurity content.

[0005] A certain company on the market has built a pilot-scale production device for catalytically synthesizing 2-nitropropane using the aminooxidation method. There are nearly ten thousand tons of production devices for this product in China, and a large number of deactivated titanium silicalite will be produced after they are put into operation. If these deactivated titanium silicalite are directly treated as hazardous waste, it will inevitably cause resource waste. If 2,3-dimethyl-2,3-dinitrobutane in the deactivated catalyst can be recovered, it can not only reduce the cost of hazardous waste treatment, but also increase economic benefits. SUMMARY

[0006] In view of the above-mentioned defects or deficiencies in the prior art, it is desirable to provide a method for extracting 2,3-dimethyl-2,3-dinitrobutane from deactivated titanium silicalite catalyst.

[0007] According to the technical scheme provided by the embodiments of the present application, a method for extracting 2,3-dimethyl-2,3-dinitrobutane from deactivated titanium silicalite catalyst is provided, which comprises the following steps:

[0008] A1, adding raw deactivated titanium silicalite catalyst to a stirred tank, then adding a solvent, stirring in the stirred tank with the raw material and the solvent, and heating at the same time for 1-3 h, and the temperature inside the stirred tank is 56-82℃, and the pressure is 0.1-0.3 Mpa, then obtaining a mixed solution I containing byproducts;

[0009] A2, the mixed solution I containing by-products in step A1 is subjected to hot filtration to perform first solid-liquid separation to obtain mixed solution II;

[0010] A3, the mixed solution II in step A2 is subjected to low-temperature evaporation concentration to obtain concentrated solution III, and the low-temperature evaporation is performed at a temperature of 56-82℃.

[0011] A4, after the concentrated solution III obtained in step A3 is subjected to cooling crystallization, second solid-liquid separation is performed to obtain a solid, and the solid is subjected to washing with a detergent.

[0012] A5, the solid obtained in step A4 is subjected to vacuum drying to obtain 2,3-dimethyl-2,3-dinitrobutane.

[0013] In the present application, preferably, the solvent is one of ethyl acetate, acetonitrile and acetone, or a composite solvent mixed with water, and the mass ratio of the solvent to the raw material is 1.0-4.0:1.

[0014] In the present application, preferably, the mass ratio of the solvent to the raw material is most preferably 2-3.5:1.

[0015] In the present application, preferably, the mass ratio of ethyl acetate, acetone, acetonitrile to water in the composite solvent is 1:0-0.2.

[0016] In the present application, preferably, the mass ratio of ethyl acetate, acetone, acetonitrile to water in the composite solvent is most preferably 1:0.01-0.05.

[0017] In the present application, preferably, the first solid-liquid separation of the mixed solution in step A2 adopts vacuum hot filtration, and the filtration is performed at a temperature of 40-50℃ and a vacuum degree of 0.05-0.07 MPa.

[0018] In the present application, preferably, the concentration of the target product in the concentrated solution III in step A3 is controlled to be 10%-15%.

[0019] In the present application, preferably, the second solid-liquid separation in step A4 adopts nitrogen pressure filtration, the pressure is controlled to be 0.1-0.2 MPa, the amount of the detergent used is 0.5-1 times the mass of the product, and the temperature of the detergent is controlled to be -5- -10℃.

[0020] In the present application, preferably, the step A5 adopts vacuum drying, the vacuum degree is controlled to be 0.03-0.05 MPa, the drying temperature is controlled to be 50-70℃, and the drying time is 5-8 h.

[0021] In summary, the present application has the following beneficial effects: through the method of solvent purification, the product is recycled, and the economic benefit is improved. Attached Figure Description

[0022] Figure 1 A diagram illustrating the process of dissolving and precipitating 2,3-dimethyl-2,3-dinitrobutane in a solvent for a deactivated titanium silicate molecular sieve catalyst;

[0023] Figure 2 This is a gas phase mass spectrometry analysis diagram of the substance in this invention. Detailed Implementation

[0024] The present application will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, only the parts relevant to the invention are shown in the accompanying drawings.

[0025] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0026] In this scheme, the deactivated titanium-silicon molecular sieve catalyst is preferably a catalyst for preparing 2-nitropropane or co-producing 2-nitropropane and acetone oxime, and the deactivated titanium-silicon molecular sieve catalyst contains 5%-10% water.

[0027] Example 1

[0028] (1) Dissolve

[0029] Take 100 kg of deactivated titanium-silicon molecular sieve catalyst and add it to a stirred tank. Then add 300 kg of ethyl acetate, turn on the stirring and jacket heating steam. When the temperature inside the tank reaches 77°C and the system refluxes, keep it at that temperature for 2 hours.

[0030] (2) Thermal filtration

[0031] After refluxing for 2 hours, stop heating and quickly transfer the material to a vacuum filter tank for hot filtration. During the filtration process, always maintain the liquid temperature at no less than 45-50℃.

[0032] (3) Concentration

[0033] The liquid containing 2,3-dimethyl-2,3-dinitrobutane obtained after hot filtration was transferred to a flash evaporator, and the bottom temperature of the vessel was controlled at 77-78℃, resulting in the distillation of 249 kg of solvent.

[0034] (4) Crystallization and Separation

[0035] The concentrated solution 60 kg is transferred to a crystallization kettle, condensed water is introduced into the jacket, the temperature in the kettle is slowly reduced to -5°C, and after 2 h of incubation, the material is transferred to a nitrogen pressure filter tank for pressure filtration to obtain the crude 2,3-dimethyl-2,3-dinitrobutane. The solid obtained by filtration is washed with 5 kg of ethyl acetate pre-cooled to -5°C, and then filtered again to obtain a solid.

[0036] (5) Drying

[0037] The solid obtained by centrifugation is transferred to a vacuum oven for drying, the temperature in the oven is controlled at 70°C, the vacuum degree is -0.05 Mpa, and the drying is performed for 5 h, and then the temperature is cooled to room temperature to obtain 2,3-dimethyl-2,3-dinitrobutane 8.37 kg, with a product purity of 99.7%.

[0038] Example 2

[0039] (1) Dissolution

[0040] 100 kg of deactivated titanium silicalite molecular sieve catalyst is taken and added to a stirred kettle, then 200 kg of acetonitrile and 40 kg of demineralized water are added, stirring is started, and jacket heating steam is turned on. When the temperature in the kettle reaches 81°C and the system starts to reflux, incubate for 2 h.

[0041] (2) Hot filtration

[0042] After 2 h of reflux, stop heating and quickly transfer the material to a vacuum filter tank for hot filtration. The temperature of the material is maintained at 45-50°C during the filtration process.

[0043] (3) Concentration

[0044] The liquid containing 2,3-dimethyl-2,3-dinitrobutane obtained after hot filtration is transferred to a flash tank, and the kettle bottom temperature is controlled at 81-82°C. Evaporate 162 kg of solvent.

[0045] (4) Crystallization and separation

[0046] The 86 kg of material obtained by filtration is transferred to a crystallization kettle, condensed water is introduced into the jacket, and the temperature in the kettle is slowly reduced to -7°C. After 2 h of incubation, the material is transferred to a nitrogen pressure filter tank for pressure filtration. The solid obtained by filtration is washed with 5.0 kg of solvent (4.2 kg of acetonitrile and 0.8 kg of demineralized water) pre-cooled to -5°C, and then pressure filtered again.

[0047] (5) Drying

[0048] The solid obtained is transferred to a vacuum oven for drying, the temperature in the oven is controlled at 65°C, the vacuum degree is -0.05 Mpa, and the drying is performed for 5 h, and then the temperature is cooled to room temperature to obtain 2,3-dimethyl-2,3-dinitrobutane 8.08 kg, with a product purity of 99.5%

[0049] Example 3

[0050] (1) Dissolution

[0051] Take 100 kg of deactivated titanium silicalite catalyst, add it to a stirred tank, then add 250 kg of acetone and 12 kg of demineralized water. Start stirring and jacket heating with steam. When the temperature in the tank reaches 56°C and the system starts to reflux, maintain the temperature for 2 hours.

[0052] (2) Hot filtration

[0053] After refluxing for 2 hours, stop heating and quickly transfer the material for hot filtration. Maintain the temperature of the material at 43-45°C during the filtration process.

[0054] (3) Concentration

[0055] After hot filtration, transfer the obtained liquid containing 2,3-dimethyl-2,3-dinitrobutane to a flash tank. Control the tank bottom temperature at 56°C and evaporate 200 kg of solvent.

[0056] (4) Crystallization and separation

[0057] Transfer the filtered material to a crystallization tank. Pass condensed water through the jacket and slowly reduce the temperature in the tank to -7°C. Maintain the temperature for 2 hours, then transfer the material to a nitrogen pressure filter tank for pressure filtration. Add 5.25 kg of pre-cooled to -5°C washing solvent (5 kg of acetone and 0.25 kg of water) to the filtered solid and wash thoroughly. Then pressure filter again to obtain the solid.

[0058] (5) Drying

[0059] Transfer the obtained solid to a vacuum oven for drying. Control the temperature in the oven at 50°C and the vacuum degree at -0.05 Mpa. Dry for 5 hours, then cool to room temperature. Obtain 8.25 kg of 2,3-dimethyl-2,3-dinitrobutane with a purity of 99.5%.

[0060] Example 4

[0061] (1) Dissolution

[0062] Take 100 kg of deactivated titanium silicalite catalyst, add it to a stirred tank, then add 150 kg of ethyl acetate. Start stirring and jacket heating with steam. When the temperature in the tank reaches 77-78°C and the system starts to reflux, maintain the temperature for 2 hours.

[0063] (2) Hot filtration

[0064] After refluxing for 2 hours, stop heating and quickly transfer the material to a vacuum filter tank for hot filtration. Maintain the temperature of the material at 45-50°C during the filtration process.

[0065] (3) Concentration

[0066] The liquid containing 2,3-dimethyl-2,3-dinitrobutane after hot filtration was transferred to a flash tank, the temperature of the tank bottom was controlled at 78°C, and 90 kg of solvent was evaporated.

[0067] (4) Crystallization and separation

[0068] The liquid 68 kg obtained by filtration was transferred to a crystallization tank, condensed water was introduced into the jacket, the temperature in the tank was slowly reduced to -7°C, and after 2 h of incubation, the material was transferred to a nitrogen pressure filter tank for pressure filtration. The obtained solid was washed with 5 kg of ethyl acetate pre-cooled to -5°C, and then pressure filtered to obtain a solid

[0069] (5) Drying

[0070] The obtained solid was transferred to a vacuum oven for drying, the temperature in the oven was controlled at 70°C, the vacuum degree was -0.05 Mpa, and the drying was performed for 5 h, and then cooled to room temperature to obtain 2,3-dimethyl-2,3-dinitrobutane 8.65 kg, with a product purity of 98.0%.

[0071] As shown in Figure 1 , the process diagram of the deactivated titanium silicalite molecular sieve catalyst dissolving in the solvent and precipitating 2,3-dimethyl-2,3-dinitrobutane. For Figure 1 , the following table is further described.

[0072]

[0073] Peak area refers to: the differential curve of the response signal generated by the components flowing out of the chromatographic column through the detector system is called a chromatographic peak, and the area enclosed by the peak to the baseline is called the peak area.

[0074] Peak height refers to: the height between the intersection point of the concentration maximum point of the chromatographic peak and the time coordinate and the baseline is called the peak height.

[0075] Peak width refers to: the intercept on the baseline by the tangent line passing through the inflection points on both sides of the chromatographic peak is called the peak width.

[0076] Peak area ratio: represents the relative percentage content of each substance. It is generally used to investigate the purity of the test product.

[0077] The process is simple, the required equipment is less, and the recycling of resources is fully realized. Moreover, for the manufacturers using the catalyst, the extraction of by-products is also beneficial to reduce the production cost.

[0078] As shown in Figure 2 , it is the gas chromatography-mass spectrometry analysis diagram of the present scheme.

[0079] The above description is merely the preferred embodiments of the present application and the technical principles and schemes applied. Meanwhile, the scope of the present application is not limited to the technical solutions formed by the specific combinations of the technical features described above, and should also cover other technical solutions formed by the combinations of the technical features described above or their equivalent features without departing from the inventive concept. For example, the technical solutions formed by the mutual replacement of the features described above and the technical features disclosed in the present application (but not limited to) with similar functions.

Claims

1. Process for the extraction of 2,3-dimethyl-2,3-dinitrobutane from an inactivated titanium silicalite molecular sieve catalyst, characterized in that, The method comprises the following steps: A1, the raw material of the deactivated titanium silicalite molecular sieve catalyst is added to a stirred tank, then a solvent is added, stirring is carried out in the stirred tank with the raw material and the solvent, and heating is carried out at the same time for 1-3 h, the temperature inside the stirred tank is 56-82°C, and the pressure is 0.1-0.3 MPa, then a mixed solution I containing by-products is obtained; A2, the mixed solution I containing by-products in step A1 is subjected to hot filtration, and first solid-liquid separation is carried out, to obtain a mixed solution II; A3, the mixed solution II in step A2 is subjected to low-temperature evaporation concentration, to obtain a concentrated solution III, and the temperature of the low-temperature evaporation is 56-82°C; A4, after the concentrated solution III obtained in step A3 is cooled and crystallized, second solid-liquid separation is carried out, to obtain a solid, and the solid is washed with a detergent; A5, the solid obtained in step A4 is subjected to vacuum drying, to obtain 2,3-dimethyl-2,3-dinitrobutane; The raw material of the deactivated titanium silicalite molecular sieve catalyst is a catalyst for preparing 2-nitropropane, and the water content in the deactivated titanium silicalite molecular sieve catalyst is 5%-10%; The solvent is one of ethyl acetate, acetonitrile and acetone, or a composite solvent mixed with water, and the mass ratio of the solvent to the raw material is 1.0-4.0:1; In step A2, the first solid-liquid separation of the mixed solution is carried out by vacuum hot filtration, and the temperature is kept at 40-50°C, and the vacuum degree is 0.05-0.07 MPa; In step A3, the concentration of the target product in the concentrated solution III is controlled to be 10%-15%; In step A4, the second solid-liquid separation is carried out by nitrogen pressure filtration, the pressure is controlled to be 0.1-0.2 MPa, and the temperature of the detergent is controlled to be -5-10°C.

2. The process of claim 1 for extracting 2,3-dimethyl-2,3-dinitrobutane from a deactivated titanium silicalite catalyst, characterized by: The mass ratio of the solvent to the raw material is 2-3.5:

1.

3. The process for extracting 2,3-dimethyl-2,3-dinitrobutane from a deactivated titanium silicalite catalyst according to claim 1 characterized by: In the composite solvent, the mass ratio of ethyl acetate, acetone and acetonitrile to water is 1:0.01-0.

05.

4. The process of claim 1 for extracting 2,3-dimethyl-2,3-dinitrobutane from a deactivated titanium silicalite catalyst, characterized by: In step A5, vacuum drying is carried out, the vacuum degree is controlled to be 0.03-0.05 MPa, the drying temperature is controlled to be 50-70°C, and the drying time is 5-8 h.

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