A method for preparing 1,6-hexanedial, the obtained product, and a reaction system

Abstract

A method for preparing 1,6-hexanedial, the obtained product, and a reaction system, and relate to the technical field of fine chemical synthesis. The method comprises: mixing cyclohexene with a solvent, introducing a gas containing ozone, and reacting cyclohexene with ozone to obtain 1,6-hexanedial under normal pressure and a temperature of 70-20°C; the solvent contains dimethyl sulfoxide and water. The present invention utilizes the high selectivity of the green oxidant ozone to olefin double bonds, and selectively oxidizes cyclohexene in a mixed solvent system to prepare 1,6-hexanedial in one step. The present invention does not need to introduce a precious metal complex and a solid catalyst such as sodium periodate into the reaction system, and the preparation method is simple in process, green, environmentally friendly and pollution-free.

Description

Technical Field

[0001] The invention relates to the technical field of fine chemical synthesis, and in particular to a method for preparing 1,6-hexanedialdehyde. Background Art

[0002] 1,6-Hexanedial is an important chemical product with a wide range of uses. Because it has excellent killing properties against viruses, bacteria, fungi, spores, etc., and does not cause damage or corrosion to the human body, metal utensils, glassware and plastic products, it is widely used in the field of disinfection and sterilization of instruments and foods. At the same time, due to its inhibitory effect on sulfate-reducing bacteria, it is used in the field of oil extraction to reduce the sulfur content of crude oil to a certain extent. 1,6-Hexanedial is an excellent cross-linking agent with the advantages of high activity, large binding capacity, rapid reaction, stable product, strong acid, water and enzyme resistance, etc. It can be used in the medical field of repair and bonding of biological tissues and organs. Hexanedial is also a good leather tanning agent, which makes the leather sweat-resistant, heat-resistant, soap-resistant, bright in color, and fine and uniform in texture. At the same time, 1,6-hexanedialdehyde is also a potential chemical intermediate used in the production of important chemical products. CN111072490A discloses a method for preparing hexanediamine, an important monomer for preparing nylon, by ammoniation and hydrogenation of 1,6-hexanedialdehyde, with a hexanediamine yield of more than 80%.

[0003] 1,6-Hexanedial can be prepared by using sodium periodate / silica gel system. "Efficient and Facile GlycolCleavage Oxidation Using Improved Silica Gel-Supported Sodium Metaperiodate" (J.Org.Chem.1997,62,2622-2624) uses 1,6-cyclohexanediol as raw material and uses silica gel supported sodium periodate system to prepare 1,6-hexanedial, and the yield of hexanedial reaches 98%. "Research on Synthesis Technology of 1,6-Hexanedial" (Fragrances, Flavors and Cosmetics, 2006 (6): 17-20) uses trans-1,2-cyclohexanediol obtained by oxidation of cyclohexene as raw material and uses sodium iodate / silica gel system to prepare 1,6-hexanedial, and the raw material conversion rate reaches 99%, and the yield of 1,6-hexanedial is 87%. Although this system is relatively efficient, the catalyst system used is expensive, the catalyst is easy to deteriorate and deactivate, and it is not easy to store and handle.

[0004] US5312996A and CN1087078A disclose a method for preparing 1,6-hexanedial by hydroformylation reaction using butadiene, carbon monoxide and hydrogen as raw materials. Although the preparation method is simple and the raw materials used are stable, cheap and easily available, the catalyst used is a rhodium catalyst, which is expensive, and the selectivity of 1,6-hexanedial is only 30%.

[0005] "Selective Oxidation of Cyclopentene to Glutaraldehyde by Hydrogen Peroxide Catalyzed by Perniobate Acid" (Journal of Fudan University (Natural Science Edition), 2002, 41(3): 317-319) reported a method for preparing 1,6-hexanedial using cyclohexene as a raw material. Perniobate acid was used as a catalyst, ethanol was used as a solvent, and hydrogen peroxide was used as an oxidant. The cyclohexene conversion rate was 100%, but the selectivity of 1,6-hexanedial was only 40%.

[0006] CN109369356A discloses a method for preparing 1,6-hexanedial by selectively oxidizing cyclohexene using a cobalt complex of an isosterol derivative as a catalyst and oxygen as an oxidant. Although a high yield of hexanedial can be achieved, the ligand structure of the isosterol derivative is complex and the preparation process is complicated. "Photooxidation of cyclohexane andcyclohexene in BaY" (Journal of Molecular Catalysis A: Chemical 194 (2003) 169-180) uses cyclohexane as a raw material, and in a BaY molecular sieve / tert-butyl hydroperoxide system, cyclohexene is oxidized by light and oxygen as an oxidant. The product is a mixture of cyclohexene epoxide 1,6-hexanedial acid, 1,6-hexanedial, etc., wherein the selectivity of 1,6-hexanedial is less than 25%. CN111138256A discloses a method for preparing 1,6-adipaldehyde by oxidizing cyclohexene using molecular sieve-loaded metal oxide as catalyst, lipids as auxiliary agent and ozone as oxidant, and the yield of adipaldehyde is close to 50%.

[0007] In summary, among the above methods for preparing 1,6-hexanedial, although the sodium periodate / silica gel system is highly efficient in preparing 1,6-hexanedial, the catalyst system is costly, the catalyst is easily deteriorated and deactivated, and is difficult to store and handle. 1,6-hexanedial is prepared by hydroformylation using butadiene as a raw material. Although the raw material is stable and cheap and readily available, the current selectivity is too low. The preparation of 1,6-hexanedial using oxygen or peroxide systems has the disadvantages of over-oxidation and low selectivity. Therefore, it is of great significance to develop a green, environmentally friendly, efficient, and easy-to-industrial 1,6-hexanedial preparation technology. Summary of the invention

[0008] One of the technical problems to be solved by the present invention is to propose a one-step method for preparing 1,6-hexanedial and the obtained product based on the existing technology and targeting the deficiencies of the 1,6-hexanedial preparation technology. The reaction system does not need to introduce a solid catalyst, the preparation method is simple in process, and is green, environmentally friendly and pollution-free.

[0009] The second technical problem to be solved by the present invention is to provide a reaction system for preparing 1,6-hexanedialdehyde.

[0010] The invention provides a method for preparing 1,6-hexanedialdehyde, comprising: mixing cyclohexene with a solvent, introducing a gas containing ozone, and performing an oxidation reaction between the cyclohexene and the ozone under normal pressure and a temperature of -70-20°C to obtain 1,6-hexanedialdehyde; the solvent contains dimethyl sulfoxide and water.

[0011] The present invention provides a 1,6-adipaldehyde product prepared by the method for preparing 1,6-adipaldehyde.

[0012] The invention provides a reaction system for preparing 1,6-hexanedialdehyde, comprising an ozone generating unit, a premixing tank, a reactor, a buffer tank, a normal pressure distillation tower and a reduced pressure distillation tower which are connected in sequence.

[0013] The method for preparing 1,6-hexanedialdehyde provided by the present invention, the obtained product and the reaction system have the following beneficial effects:

[0014] The method for preparing 1,6-hexanedialdehyde provided by the present invention utilizes the high selectivity of the green oxidant ozone for olefin double bonds to selectively oxidize cyclohexene in a mixed solvent system to prepare 1,6-hexanedialdehyde in one step. The molecular orbital of ozone is similar to the allyl molecular orbital in the cyclohexene molecule, and cyclohexene can be highly selectively oxidized. The ozonation reaction has few side reactions, high reaction selectivity, low threshold of reaction conditions, and the oxidant is green and environmentally friendly. In the reaction system, ozone preferentially reacts with the double bond of cyclohexene to generate primary and secondary ozonides, and the secondary ozonides react with water to generate aldehydes and hydrogen peroxide. The dimethyl sulfoxide in the solvent consumes the generated hydrogen peroxide to reduce the over-oxidation of the generated aldehyde. The reaction system is simple and does not require the introduction of a solid catalyst with high price or complicated preparation process. The method provided by the present invention has low preparation cost, simple process flow, green and environmentally friendly, and is conducive to industrial scale-up.

[0015] The reaction system for preparing 1,6-hexanedial provided by the present invention is suitable for the method for preparing 1,6-hexanedial. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is the FT-IR spectrum of 1,6-hexanedialdehyde obtained in Example 1.

[0017] Figure 2 The mass spectrum of 1,6-hexanedialdehyde obtained in Example 1.

[0018] Figure 3 This is the H-NMR spectrum of 1,6-hexanedialdehyde obtained in Example 1.

[0019] Figure 4 This is the C-NMR spectrum of 1,6-hexanedialdehyde obtained in Example 1.

[0020] Figure 5The present invention provides a schematic flow diagram of a reaction system for preparing 1,6-hexanedialdehyde.

[0021] Reference numerals:

[0022] 1-reactor, 2-atmospheric distillation tower, 3-vacuum distillation tower, 4-ozone generating unit, 5-ozone buffer tank, 6-solvent tank, 7-premixing tank, 9-condenser, 8-raw material pipeline, 10, 11, 12-pipeline DETAILED DESCRIPTION

[0023] The specific embodiments of the present invention are described in detail below. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0024] In this application, the so-called "upper part", "lower part" and "bottom" are all based on the relative position relationship of the container or the component. Among them, the "bottom" refers to the position of 0-10% from the bottom to the top of the container, and the "top" refers to the position of 90-100% from the bottom to the top of the container.

[0025] In a first aspect, the present invention provides a method for preparing 1,6-hexanedialdehyde, comprising: mixing cyclohexene with a solvent, introducing a gas containing ozone, and subjecting the cyclohexene to an oxidation reaction with the ozone at normal pressure and a temperature of -70-20°C to obtain 1,6-hexanedialdehyde; the solvent contains dimethyl sulfoxide and water.

[0026] In the method provided by the present invention, optionally, the solvent containing dimethyl sulfoxide further contains: one or more selected from methanol, ethanol, dichloromethane, acetic acid, cyclohexane, 1,2-dichloroethane, ethyl acetate, n-decane, acetic anhydride, N,N-dimethylformamide and chloroform;

[0027] More preferably, the solvent further contains methanol and / or dichloromethane.

[0028] Optionally, the mass content of dimethyl sulfoxide in the solvent is 5wt%-83wt%, preferably 17wt%-35wt%.

[0029] Preferably, the solvent consists of dimethyl sulfoxide, dichloromethane and water, and the mass ratio of dimethyl sulfoxide, dichloromethane and water is (0.05-10):1:(0.05-0.8); preferably, the mass ratio of dimethyl sulfoxide, dichloromethane and water is (0.2-5):1:(0.1-0.7); more preferably, the mass ratio of dimethyl sulfoxide, dichloromethane and water is (0.2-5):1:(0.4-0.6).

[0030] Alternatively, the solvent consists of dimethyl sulfoxide, methanol and water, and the mass ratio of dimethyl sulfoxide, methanol and water is (0.05-10):1:(0.05-0.8); preferably, the mass ratio of dimethyl sulfoxide, methanol and water is (0.2-5):1:(0.1-0.7); more preferably, the mass ratio of dimethyl sulfoxide, methanol and water is (0.2-5):1:(0.4-0.6).

[0031] Optionally, the mass ratio of cyclohexene to solvent is 0.01-0.30:1; preferably, the mass ratio of cyclohexene to solvent is 0.025-0.2:1.

[0032] Optionally, the ozone-containing gas also contains one or more of oxygen, air, nitrogen and argon; preferably, the ozone-containing gas consists of ozone and oxygen.

[0033] Preferably, the concentration of ozone in the ozone-containing gas is 5-150 g / m 3 More preferably, the concentration of ozone is 100-140 g / m 3 .

[0034] In the method provided by the present invention, the reaction time of cyclohexene and ozone is 4-60 min, preferably 5-30 min, the oxidation reaction obtains 1,6-hexanedialdehyde, the reaction temperature is preferably -10-5°C, and the flow rate of the introduced gas is 10-600 mL / min, preferably 50-300 mL / min.

[0035] In the method provided by the present invention, after the oxidation reaction is completed, the reactant stream is subjected to a separation operation to obtain a 1,2-hexanedialdehyde product. Optionally, the separation operation is a combination of atmospheric distillation, vacuum distillation, rotary evaporation, extraction and column chromatography or more. On a laboratory scale, it is preferably a combination of rotary evaporation and vacuum distillation, and the low-boiling solvent in the reactant stream is separated by rotary evaporation, and then the product 1,6-hexanedialdehyde is distilled out by vacuum distillation. Specifically, at 20-3°C and a pressure of 2-8kPa, rotary evaporation removes a large amount of low-boiling solvents (dichloromethane, methanol, dimethyl sulfoxide, etc.), and the residue is then subjected to vacuum distillation, and the target product hexanedialdehyde is separated under the conditions of a pressure of 50-500Pa and a temperature of 40-60°C, and the remaining substances are high-boiling byproducts or polymers.

[0036] Optionally, the reaction stream is separated by distillation and / or extraction to obtain a 1,6-hexanedialdehyde product.

[0037] In a second aspect, the present invention provides a 1,6-adipaldehyde product prepared by a method for preparing 1,6-adipaldehyde. The purity of the 1,6-adipaldehyde product obtained by the present invention is greater than 70wt%, and the product also contains cyclic byproducts, polymer byproducts and residual solvents.

[0038] In a third aspect, the present invention provides a reaction system for preparing 1,6-hexanedialdehyde, comprising an ozone generating unit, a reactor, an atmospheric distillation tower and a vacuum distillation tower connected in sequence, wherein the ozone generating unit is connected to the bottom of the reactor, and a liquid raw material feed pipeline is connected to the upper part of the reactor.

[0039] The top discharge of the atmospheric distillation tower is connected to the liquid phase feed pipeline through a cooling and condensing device. In the reactor, cyclohexene is mixed with a solvent and reacts with the introduced ozone gas to obtain 1,6-hexanedialdehyde, and the solvent contains dimethyl sulfoxide and water.

[0040] The reaction system for preparing 1,6-hexanedialdehyde provided by the present invention is described in detail below with reference to the accompanying drawings. Figure 5 The schematic diagram of the process of the reaction system for preparing 1,6-hexanedialdehyde provided by the present invention is shown in the attached figure. Figure 5 It can be seen that the reaction system includes an ozone generating unit 4, an ozone buffer tank 5, an oxidation reactor 1, an atmospheric distillation tower 2 and a vacuum distillation tower 3 which are connected in sequence. The raw material from pipeline 8 is mixed with the solvent from the solvent storage tank 6 in the premixing tank 7, and then connected to the upper part of the oxidation reactor 1 through the liquid raw material pipeline 13. The reacted material enters the atmospheric distillation tower 2 through pipeline 14, and most of the solvent is discharged from the top of the tower. After cooling by the cooling condensation device 9, it returns to the solvent storage tank, and part of the gas is discharged through pipeline 12. The bottom discharge of the atmospheric distillation tower 2 enters the vacuum distillation tower 3 through pipeline 15. After vacuum distillation, 1,6-hexanedialdehyde is discharged from the top of the tower through pipeline 10, and part of the by-products are discharged from the bottom of the tower.

[0041] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0042] The present invention will be described in detail below through examples.

[0043] Unless otherwise specified, the raw materials in the examples of the present invention were purchased from commercial sources.

[0044] The analysis method in the embodiment is as follows:

[0045] The quantitative analysis of reactants and products was performed using an Agilent 7890B gas chromatograph from the United States. Propylene glycol methyl ether was used as the internal standard and the internal standard method was used for quantitative calculation.

[0046] The infrared spectrum of the product was characterized using the American Thermo Fisher IS50 Fourier transform infrared spectrometer.

[0047] The mass spectrometer of the product was characterized by Agilent 7890-5975 GC / MS.

[0048] The product's hydrogen spectrum and carbon spectrum were characterized using the American Bruker Avance NEO nuclear magnetic resonance instrument.

[0049] The conversion of the reactants and the selectivity of the products in the examples are calculated as follows:

[0050] Cyclohexene conversion rate (mol) = (the amount of cyclohexene added before the reaction - the amount of cyclohexene remaining after the reaction) / (the amount of cyclohexene added before the reaction) × 100%.

[0051] 1,6-hexanedial selectivity (mol) = (the amount of 1,6-hexanedial generated after the reaction) / (the amount of cyclohexene converted during the reaction) × 100%.

[0052] The purity of 1,6-adipaldehyde product refers to the mass content of 1,6-adipaldehyde in the product.

[0053] Example 1

[0054] 1 g of cyclohexene was added to a homemade jacketed four-necked reaction flask, and 7.5 g of dichloromethane and 1.5 g of dimethyl sulfoxide were added respectively, and then 0.5 g of water was added. The reaction flask was stirred magnetically, and the jacket refrigeration was turned on to reduce the temperature of the reactor solution to -5 °C. A mixed gas of ozone and oxygen was introduced, and the air flow rate was controlled to be 100 mL / min, and the ozone concentration was 120 g / m 3 , the bubbling reaction was continued for 10 minutes, and the gas was switched to nitrogen to exhaust the remaining oxygen and ozone in the system. The mixed solution obtained by the reaction was subjected to rotary evaporation and vacuum distillation to obtain 1,6-hexanedial product. The cyclohexene conversion rate, 1,6-hexanedial selectivity and 1,6-hexanedial product purity are shown in Table 1.

[0055] in, Figure 1 is the FT-IR spectrum of the product, Figure 1 It can be seen that 2942cm -1 The peak at 2733 cm is the CH stretching vibration absorption peak in the methylene group. -1 The peak at 1723 cm is the CH stretching vibration absorption peak inside the carbonyl group. -1 The strong absorption peak is the absorption peak of carbonyl.

[0056] Figure 2is the mass spectrum of the product, Figure 2 It can be seen that the product spectrum is similar to the standard spectrum of 1,6-hexanedialdehyde Figure 1 To.

[0057] Figure 3 is the H-NMR spectrum of the product, Figure 3 It can be seen that (1H NMR (500 MHz, Chloroform-d) δ 9.74 (t, J = 5.6 Hz, 1H), 2.40-2.28 (m, 2H), 1.65-1.53 ​​(m, 2H)).

[0058] Figure 4 is the C-NMR spectrum of the product, Figure 3 It can be seen that the product spectrum is similar to the standard spectrum of 1,6-hexanedialdehyde Figure 1 13C NMR (125MHz, Common NMR Solvents)δ202.53,42.95,21.44.

[0059] Example 2

[0060] 1 g of cyclohexene was added to a homemade jacketed four-necked reaction flask, and 7.5 g of dichloromethane and 1.5 g of dimethyl sulfoxide were added respectively, and then 0.5 g of water was added. The reaction flask was stirred magnetically, and the jacket refrigeration was turned on to reduce the temperature of the reactor solution to -8 °C. A mixed gas of ozone and oxygen was introduced, and the air flow rate was controlled to be 100 mL / min, and the ozone concentration was 120 g / m 3 The bubbling reaction was continued for 10 minutes, and the gas was switched to nitrogen to exhaust the remaining oxygen and ozone in the system. The mixed solution obtained by the reaction was subjected to rotary evaporation and vacuum distillation to obtain 1,6-hexanedial product. The cyclohexene conversion rate and 1,6-hexanedial selectivity are shown in Table 1.

[0061] Example 3

[0062] 1 g of cyclohexene was added to a homemade jacketed four-necked reaction flask, and 7.5 g of dichloromethane and 1.5 g of dimethyl sulfoxide were added respectively, and then 0.5 g of water was added. The reaction flask was stirred magnetically, and the jacket refrigeration was turned on to reduce the temperature of the reactor solution to -20 °C. A mixed gas of ozone and oxygen was introduced, and the air flow rate was controlled to be 100 mL / min, and the ozone concentration was 120 g / m 3 , the bubbling reaction was continued for 10 minutes, and the gas was switched to nitrogen to exhaust the remaining oxygen and ozone in the system. The mixed solution obtained by the reaction was subjected to rotary evaporation and vacuum distillation to obtain 1,6-hexanedial product. The cyclohexene conversion rate and 1,6-hexanedial selectivity are shown in Table 1.

[0063] Example 4

[0064] 1 g of cyclohexene was added to a homemade jacketed four-necked reaction flask, and 6 g of dichloromethane and 3 g of dimethyl sulfoxide were added respectively, and then 0.5 g of water was added. The reaction flask was stirred magnetically, and the jacket refrigeration was turned on to reduce the temperature of the reactor solution to 0 °C. A mixed gas of ozone and oxygen was introduced, and the air flow rate was controlled to be 100 mL / min and the ozone concentration was 120 g / m 3 The bubbling reaction was continued for 10 minutes, and the gas was switched to nitrogen to exhaust the remaining oxygen and ozone in the system. The mixed solution obtained by the reaction was subjected to rotary evaporation and vacuum distillation to obtain 1,6-hexanedial product. The cyclohexene conversion rate and 1,6-hexanedial selectivity are shown in Table 1.

[0065] Example 5

[0066] 1 g of cyclohexene was added to a homemade jacketed four-necked reaction flask, and 7.5 g of dichloromethane and 1.5 g of dimethyl sulfoxide were added respectively, and then 0.5 g of water was added. The reaction flask was stirred magnetically, and the jacket refrigeration was turned on to reduce the temperature of the reactor solution to 0 °C. A mixed gas of ozone and oxygen was introduced, and the air flow rate was controlled to be 200 mL / min and the ozone concentration was 120 g / m 3 The bubbling reaction was continued for 10 minutes, and the gas was switched to nitrogen to exhaust the remaining oxygen and ozone in the system. The mixed solution obtained by the reaction was subjected to rotary evaporation and vacuum distillation to obtain 1,6-hexanedial product. The cyclohexene conversion rate and 1,6-hexanedial selectivity are shown in Table 1.

[0067] Example 6

[0068] 1 g of cyclohexene was added to a homemade jacketed four-necked reaction flask, and 7.5 g of dichloromethane and 1.5 g of dimethyl sulfoxide were added respectively, and then 0.5 g of water was added. The reaction flask was stirred magnetically, and the jacket refrigeration was turned on to reduce the temperature of the reactor solution to 0 °C. A mixed gas of ozone and oxygen was introduced, and the air flow rate was controlled to be 100 mL / min, and the ozone concentration was 120 g / m 3 The bubbling reaction was continued for 22 minutes, and the gas was switched to nitrogen to exhaust the remaining oxygen and ozone in the system. The mixed solution obtained by the reaction was subjected to rotary evaporation and vacuum distillation to obtain 1,6-hexanedial product. The cyclohexene conversion rate and 1,6-hexanedial selectivity are shown in Table 1.

[0069] Example 7

[0070] 1 g of cyclohexene was added to a homemade jacketed four-necked reaction flask, followed by 15.8 g of methanol and 3.2 g of dimethyl sulfoxide, and then 0.5 g of water. The reaction flask was stirred magnetically, and the jacket refrigeration was turned on to lower the temperature of the reactor solution to 0 °C. A mixed gas of ozone and oxygen was introduced, and the air flow rate was controlled at 100 mL / min and the ozone concentration was 120 g / m 3The bubbling reaction was continued for 22 minutes, and the gas was switched to nitrogen to exhaust the remaining oxygen and ozone in the system. The mixed solution obtained by the reaction was subjected to rotary evaporation and vacuum distillation to obtain 1,6-hexanedial product. The cyclohexene conversion rate and 1,6-hexanedial selectivity are shown in Table 1.

[0071] Example 8

[0072] 1 g of cyclohexene was added to a homemade jacketed four-necked reaction flask, followed by 1.9 g of methanol and 0.4 g of dimethyl sulfoxide, and then 0.5 g of water. The reaction flask was stirred magnetically, and the jacket refrigeration was turned on to lower the temperature of the reactor solution to 0 °C. A mixed gas of ozone and oxygen was introduced, and the air flow rate was controlled at 100 mL / min and the ozone concentration was 120 g / m 3 , the bubbling reaction was continued for 32 minutes, and the gas was switched to nitrogen to exhaust the remaining oxygen and ozone in the system. The mixed solution obtained by the reaction was subjected to rotary evaporation and vacuum distillation to obtain 1,6-hexanedial product. The cyclohexene conversion rate and 1,6-hexanedial selectivity are shown in Table 1.

[0073] Example 9

[0074] 1 g of cyclohexene was added to a homemade jacketed four-necked reaction flask, and 7.5 g of methanol and 1.5 g of dimethyl sulfoxide were added respectively, and then 0.5 g of water was added. The reaction flask was stirred magnetically, and the jacket refrigeration was turned on to reduce the temperature of the reactor solution to 0 °C. A mixed gas of ozone and oxygen was introduced, and the air flow rate was controlled to be 100 mL / min, and the ozone concentration was 120 g / m 3 , the bubbling reaction was continued for 10 minutes, and the gas was switched to nitrogen to exhaust the remaining oxygen and ozone in the system. The mixed solution obtained by the reaction was subjected to rotary evaporation and vacuum distillation to obtain 1,6-hexanedial product. The cyclohexene conversion rate and 1,6-hexanedial selectivity are shown in Table 1.

[0075] Example 10

[0076] 1 g of cyclohexene was added to a homemade jacketed four-necked reaction flask, and 32.5 g of methanol and 6.5 g of dimethyl sulfoxide were added respectively, and then 0.5 g of water was added. The reaction flask was stirred magnetically, and the jacket refrigeration was turned on to reduce the temperature of the reactor solution to 0 °C. A mixed gas of ozone and oxygen was introduced, and the air flow rate was controlled to be 100 mL / min, and the ozone concentration was 120 g / m 3 , the bubbling reaction was continued for 10 minutes, and the gas was switched to nitrogen to exhaust the remaining oxygen and ozone in the system. The mixed solution obtained by the reaction was subjected to rotary evaporation and vacuum distillation to obtain 1,6-hexanedial product. The cyclohexene conversion rate and 1,6-hexanedial selectivity are shown in Table 1.

[0077] Comparative Example 1

[0078] 1 g of cyclohexene was added to a homemade jacketed four-necked reaction flask, only 9 g of dichloromethane was added as solvent, and 0.5 g of water was added. Magnetic stirring was applied, and the jacket refrigeration was turned on to reduce the reactor solution temperature to -5 °C. A mixed gas of ozone and oxygen was introduced, and the air flow rate was controlled to be 100 mL / min, and the ozone concentration was 120 g / m 3 The bubbling reaction was continued for 10 minutes, and the gas was switched to nitrogen to exhaust the remaining oxygen and ozone in the system. A large amount of flocculent polymer appeared in the mixed solution obtained by the reaction, and no 1,6-hexanedialdehyde was generated, and further treatment and separation were impossible.

[0079] Comparative Example 2

[0080] 1 g of cyclohexene was added to a homemade jacketed four-necked reaction flask, only 9 g of acetic acid was added as solvent, and 0.5 g of water was added. Magnetic stirring was applied, and the jacket refrigeration was turned on to reduce the temperature of the reactor solution to 0 °C. A mixed gas of ozone and oxygen was introduced, and the air flow rate was controlled to be 100 mL / min and the ozone concentration was 120 g / m 3 , react for 10 minutes, and then switch the gas to nitrogen to exhaust the remaining oxygen and ozone in the system. During the reaction, emulsification occurs due to the coagulation of acetic acid, and flocculent polymers appear at the same time. No 1,6-hexanedialdehyde is generated, and further treatment and separation are impossible.

[0081] Comparative Example 3

[0082] 1 g of cyclohexene was added to a homemade jacketed four-necked reaction flask, followed by 7.5 g of cyclohexane and 1.5 g of acetic acid, and then 0.5 g of water. The reaction flask was stirred magnetically, and the jacket refrigeration was turned on to lower the temperature of the reactor solution to 0 °C. A mixed gas of ozone and oxygen was introduced, and the air flow rate was controlled to be 100 mL / min, and the ozone concentration was 120 g / m 3 , the bubbling reaction was continued for 10 minutes, and the gas was switched to nitrogen to exhaust the remaining oxygen and ozone in the system. A large amount of flocculent polymer appeared in the mixed solution obtained by the reaction, no 1,6-hexanedialdehyde was generated, and further treatment and separation were impossible.

[0083] Table 1

[0084] Examples Cyclohexene conversion rate / % 1,6-Hexanedial selectivity / % 1,6-Adipaldehyde product purity / % Example 1 74.0 68.2 75.0 Example 2 67.0 65.2 81.1 Example 3 64.3 63.9 74.5 Example 4 37.6 49.6 86.7 Example 5 78.9 46.1 89.2 Example 6 99.9 49.0 74.4 Example 7 63.9 21.0 87.1 Example 8 100 42.3 71.8 Example 9 80.6 20.7 81.5 Example 10 100 11.7 84.3 Comparative Example 1 82.5 / / Comparative Example 2 79.6 / / Comparative Example 3 88.6 / /

Claims

1. A method for preparing 1,6-hexanedialdehyde, characterized in that: include: Cyclohexene is mixed with a solvent, and a gas containing ozone is introduced. Under the conditions of normal pressure and temperature of -70-20°C, cyclohexene and ozone react to obtain 1,6-hexanedialdehyde, and the reaction time is 4-60 minutes. The solvent is dichloromethane, dimethyl sulfoxide and water, or methanol, dimethyl sulfoxide and water.

2. The method for preparing 1,6-hexanedialdehyde according to claim 1, characterized in that: The mass content of dimethyl sulfoxide in the solvent is 5 wt % -83 wt %.

3. The method for preparing 1,6-hexanedialdehyde according to claim 2, characterized in that: The mass content of dimethyl sulfoxide in the solvent is 17 wt %-35 wt %.

4. The method for preparing 1,6-hexanedialdehyde according to claim 1, characterized in that: The solvent is composed of dimethyl sulfoxide, dichloromethane and water, and the mass ratio of dimethyl sulfoxide, dichloromethane and water is (0.05-10):1:(0.05-0.8); or the solvent is composed of dimethyl sulfoxide, methanol and water, and the mass ratio of dimethyl sulfoxide, methanol and water is (0.05-10):1:(0.05-0.8).

5. The method for preparing 1,6-hexanedialdehyde according to claim 4, characterized in that: The mass ratio of dimethyl sulfoxide, dichloromethane and water is (0.2-5):1:(0.1-0.7); or the mass ratio of dimethyl sulfoxide, methanol and water is (0.2-5):1:(0.1-0.7).

6. The method for preparing 1,6-hexanedialdehyde according to any one of claims 1 to 5, characterized in that: The mass ratio of the cyclohexene to the solvent is 0.01-0.30:

1.

7. The method for preparing 1,6-hexanedialdehyde according to claim 6, characterized in that: The mass ratio of the cyclohexene to the solvent is 0.025-0.2:

1.

8. The method for preparing 1,6-hexanedialdehyde according to any one of claims 1 to 5, characterized in that: The gas also contains one or more of oxygen, air, nitrogen and argon, and the concentration of ozone in the gas is 5-150g / m 3 .

9. The method for preparing 1,6-hexanedialdehyde according to claim 8, characterized in that: The gas consists of ozone and oxygen.

10. The method for preparing 1,6-hexanedialdehyde according to claim 8, characterized in that: The concentration of ozone in the gas is 100-140g / m 3 .

11. The method for preparing 1,6-hexanedialdehyde according to any one of claims 1 to 5, characterized in that: The reaction time of cyclohexene and ozone is 5-30 minutes, the reaction temperature is -10-5°C, and the flow rate of the introduced gas is 10-600 mL / min.

12. The method for preparing 1,6-hexanedialdehyde according to claim 11, characterized in that: The flow rate of the introduced gas was 50-300 mL / min.

13. The method for preparing 1,6-hexanedialdehyde according to any one of claims 1 to 5, characterized in that: After the reaction is completed, the reaction stream is separated by distillation and / or extraction to obtain 1,6-hexanedialdehyde product.

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