Preparation method of 1, 12-dodecanediol

Abstract

The invention provides a preparation method of 1, 12-dodecane glycol, which comprises the following steps: by taking cyclododecatriene as a raw material, carrying out ozonization reaction to generate an ozonization intermediate, and adding a stabilizing aid into a reaction system to inhibit the reduction rate of the ozonization intermediate, so that ozonization reaction liquid can be subjected to direct quenching reaction by using hydrogen, and the 1, 12-dodecane glycol is obtained. The method has the advantages of simple operation, no generation of dangerous working conditions such as polymerization, temperature runaway and the like, realization of one-step reduction of the ozonization intermediate into long-chain diol by using more environment-friendly hydrogen as a reducing agent, low raw material cost, simple process and more competitive cost.

Description

TECHNICAL FIELD

[0001] The present application relates to a method for preparing 1,12-dodecanediol, belonging to the field of organic synthesis. BACKGROUND

[0002] 1,12-dodecanediol has application value in many fields due to its unique molecular structure (long-chain saturated diol). Its downstream applications mainly include polymer materials (polyesters, polyurethanes, epoxy resins, etc.), lubricants, surfactants and personal care products, pharmaceutical intermediates and other fine chemicals, etc. Among the various main application plates, polymers (polyesters, PU) are the largest in terms of consumption and are relatively traditional, with steady growth; emerging personal care / medicine is a growth highlight, with extremely high requirements for product quality; the lubricant and resin fields are in a medium position, with different technical requirements. Different fields have different performance requirements for 1,12-dodecanediol, but the common point is that they all prefer high-purity, high-quality products.

[0003] Patent CN110563553A uses dodecanedioic acid and n-hexanol to esterify, obtains dodecanedioic acid dihexyl ester, and then reduces the target product 1,12-dodecanediol by hydrogenation. This method can be used without catalyst, reducing the catalyst separation step, achieving esterification, reducing the production steps, and reducing the production cost. Patent CN119455955A provides a low-cost composite metal catalyst, which can use cheap and readily available 1,12-dodecanedioic acid dimethyl ester as raw material to catalyze hydrogenation to prepare 1,12-dodecanediol under milder conditions than existing technology, greatly reducing the difficulty of process condition control and improving process safety, achieving high yield and low cost.

[0004] However, the existing technology has the following disadvantages:

[0005] 1. The existing process route uses long-chain diacid reduction or lactone oxidation-ring opening reduction to obtain product 1,12-dodecanediol, which has high raw material cost and involves multiple reaction steps.

[0006] 2. The existing process has high separation difficulty and low product purity. SUMMARY

[0007] To solve the problems in the prior art, the purpose of the present application is to provide a method for preparing 1,12-dodecanediol, which uses cyclododecatriene, an intermediate in the nylon industry chain, as raw material, and through two-step reaction of ozonation and hydrogen reduction and one-step separation, high-purity 1,12-dodecanediol can be obtained, and the raw material cost is at least 1 / 2 of the traditional route.

[0008] The present application is based on experimental research, cyclododecatriene undergoes Criegee reaction under the action of ozone to generate ozonized intermediates, the reaction solution can be directly reduced by hydrogen gas with Raney nickel catalyst to 1,12-dodecanediol, and high-purity 1,12-dodecanediol can be obtained by distillation or rectification and other conventional separation methods.

[0009] The reaction equation is as follows:

[0010]

[0011] In the existing process route, dimethyl sulfide and other reducing agents are usually used to reduce the ozonized intermediates into corresponding long-chain dialdehydes, and then a step of reduction reaction is carried out to generate corresponding long-chain diols. If a weak reducing agent is used to quench the ozonized intermediates, the quenching is slow, and side reactions such as polymerization are easy to occur, resulting in a decrease in the yield of the target product; if a strong reducing agent such as hydrogen is used to quench the reaction, the strong reducing agent reacts violently with peroxide, and the reaction progress and direction cannot be controlled. Based on the research finding, the introduction of a stabilizing aid into the ozonization reaction system can inhibit the quenching rate of the ozonized intermediates, and the use of more green and environmentally friendly hydrogen as a reducing agent to reduce the ozonized intermediates into long-chain diols in one step can be realized, the raw material is low in cost, the process is simple, and the cost is more competitive.

[0012] The present application provides a preparation method of 1,12-dodecanediol, comprising the following steps:

[0013] a) ozone and cyclododecatriene are reacted in a water-containing solvent to obtain a reaction solution;

[0014] b) Raney nickel catalyst is added to the reaction solution obtained in step a), and a reduction reaction occurs under a hydrogen atmosphere.

[0015] Preferably, the reaction temperature in step a) is-80-10℃, preferably-60℃-20℃, and the reaction pressure is 0.1-5MPaA, preferably 0.1-2MPaA.

[0016] The solvent of step a) is selected from one or more of inert aliphatic alkanes, aromatic hydrocarbons, ethers, alcohols which do not react with the raw material, preferably one or more of methanol, acetone, n-heptane, and the amount of the solvent is 1-20 times, preferably 4-10 times, the mass of cyclododecatriene;

[0017] Preferably, the amount of water added in step a) is 0.1-2 times, preferably 0.2-1 times the mass of cyclododecatriene. The present application realizes the purpose of one-step reduction of ozonization intermediates to long-chain diols by introducing water as a stabilizing aid into the ozonization reaction system, and the possible principle is as follows: In step a) of ozonization reaction, water will be partially converted into hydrogen peroxide, and the generated partial hydrogen peroxide can inhibit the rapid reduction of peroxidation intermediates during reduction in step b), control the quenching rate, so that the more environmentally friendly hydrogen gas can be used as a reducing agent to one-step reduce the ozonization intermediates to long-chain diols.

[0018] In step a), the ozone is continuously introduced into the reaction system, and the total amount of ozone introduced is 1.0-1.5 times, preferably 1.1-1.3 times the molar amount of cyclododecatriene; the flow rate is 0.1-5 L / min, preferably 0.5-3 L / min; the ozone concentration is 10-50 mg / L (oxygen as carrier gas), preferably 15-30 mg / L; the required amount of ozone and the ozone introduction time are calculated according to the mass of cyclododecatriene, the ozone concentration and the flow rate, and the reaction time is strictly controlled to avoid excessive ozonation.

[0019] In step b), the hydrogenation reaction temperature is 30-120℃, preferably 50-100℃, and preferably an internal coil and chilled water are used to control the temperature during the reaction of step b) to maintain the system at the reaction temperature;

[0020] Preferably, the hydrogenation reaction pressure in step b) is 1-5 MPaA, preferably 2-4 MPaA;

[0021] In step b), the amount of Raney nickel catalyst used is 0.5-10 wt% of the mass of the raw material cyclododecatriene (the initial amount added in step a), preferably 1 wt%-5 wt%, preferably in a large excess, and is recycled and used.

[0022] Preferably, the reaction time in step b) is 5-24 h, preferably 8-16 h.

[0023] Preferably, the preparation method of the present application further comprises step c): the reaction liquid obtained from step b) is refined to obtain a qualified product.

[0024] In step c) of the present application, the refining is performed by using a rectifying column, and the rectifying column is a conventional vacuum rectifying column in the art. The bottom temperature of the rectifying column is 130-170℃, preferably 140-160℃; the top temperature is 80-130℃, preferably 85-110℃; the internal pressure is 10-500 Pa, preferably 10-100 Pa; and the number of theoretical plates is 15-25, preferably 15-20.

[0025] In the present application, the rectifying column in step c) is filled with sheet metal packing or mesh screen packing.

[0026] In the present application, the 1,12-dodecanediol reaction solution is obtained by steps a) and b) ozonation and hydrogen reduction, and the organic solvent, water, impurities, etc. are removed by one step of refining operation to obtain qualified products with a purity of greater than 99%.

[0027] The present application has the following beneficial effects:

[0028] 1. The raw material cyclododecatriene is an intermediate in the nylon industry chain, and the raw material cost is about 15000 yuan / ton, which is 1 / 2 of the raw material cost of the traditional process of dodecanedioic acid.

[0029] 2. Hydrogen is used to quench the ozonation intermediate, and one-step reduction is used to obtain 1,12-dodecanediol, which is shorter and has lower raw material cost compared to the traditional process route of reducing agent dimethyl sulfide, and the product has no unpleasant odor.

[0030] 3. The product has a large difference in boiling point from the raw material and impurities, and it is easier to obtain high-purity 1,12-dodecanediol through separation. DETAILED DESCRIPTION

[0031] The present application will be described in detail below by examples, but the present application is not limited to the following examples.

[0032] <Raw materials>

[0033] Hydrogen (99.9%), Dalian Guangming Special Gases Co., Ltd.;

[0034] Methanol, cyclododecatriene, dichloromethane, ethanol, dimethyl sulfide, China National Pharmaceutical Group;

[0035] Raney nickel catalyst, Jiangsu Xinnuo;

[0036] The remaining products have no special instructions, and are all conventional commercially available products.

[0037] <Testing method>

[0038] The gas chromatography test conditions used in the present application are as follows:

[0039] Instrument model: Agilent 7890B; chromatographic column: DB-5 (30m x 0.25mm x 0.25um); column temperature: initial temperature 80℃, temperature rising at 10℃ / min to 150℃, holding for 5min, then temperature rising at 20℃ / min to 300℃, holding for 10min; injection port temperature: 200℃; FID detector temperature: 300℃; split injection, split ratio 50:1; injection volume: 2.0um; N2flow rate: 40ml / min; H2flow rate: 400ml / min.

[0040] Example 1

[0041] The method for preparing 1,12-dodecanediol provided by the application:

[0042] 1) A three-necked flask is used to weigh 20 g of cyclododecatriene, 100 g of methanol and 10 g of pure water, and the mixture is uniformly mixed and placed in a circulating cooling bath for standby, and the circulating cooling bath is cooled.

[0043] 2) After the mixture in the three-necked flask is cooled to -50°C, ozone-purity 20 mg / L oxygen / ozone mixed gas is introduced at a flow rate of 2 L / min, the reaction pressure is 0.5 MPaA, and the reaction is carried out for 3 h. After 7.2 g of ozone is introduced in total, the introduction of the mixed gas is stopped.

[0044] 3) The ozonation reaction liquid obtained in step 2) is transferred to a reaction kettle, and Raney nickel catalyst (0.6 g) is added. The kettle cover is sealed, nitrogen is used to flush to 3 MPaA for pressure retention and leakage test, and after it is confirmed that the high-pressure kettle has good sealing performance, nitrogen is used for replacement for 3 times and then hydrogen is used for replacement for 3 times. The hydrogen in the reactor is emptied, hydrogen is used for pressure charging to 3 MPaA, the temperature is raised to 80°C, and after 12 h of heat preservation, the temperature is lowered and the pressure is released. The reaction liquid is filtered by inserting the reaction kettle into the bottom filter for collection.

[0045] 4) The reaction liquid obtained in step 3) is subjected to solvent removal, impurity removal and the like by using vacuum rectification. The bottom temperature of the rectification column is 150°C; the top temperature of the rectification column is 100°C; the pressure in the rectification column is 50 Pa; and the theoretical plate number of the rectification column is 18. 1,12-dodecanediol with a purity of >99% is collected, and the product yield is 99.4%.

[0046] Example 2

[0047] The method for preparing 1,12-dodecanediol provided by the application:

[0048] 1) A three-necked flask is used to weigh 20 g of cyclododecatriene, 100 g of methanol and 10 g of pure water, and the mixture is uniformly mixed and placed in a circulating cooling bath for standby, and the circulating cooling bath is cooled.

[0049] 2) After the mixture in the three-necked flask is cooled to -50°C, ozone-purity 20 mg / L oxygen / ozone mixed gas is introduced at a flow rate of 2 L / min, the reaction pressure is 0.5 MPaA, and the reaction is carried out for 3 h. After 7.2 g of ozone is introduced in total, the introduction of the mixed gas is stopped.

[0050] 3) The ozonation reaction liquid obtained in step 2) is transferred to a reaction kettle, and Raney nickel catalyst (0.6 g) is added. The kettle cover is sealed, nitrogen is used to flush to 3 MPaA for pressure retention and leakage test, and after it is confirmed that the high-pressure kettle has good sealing performance, nitrogen is used for replacement for 3 times and then hydrogen is used for replacement for 3 times. The hydrogen in the reactor is emptied, hydrogen is used for pressure charging to 3 MPaA, the temperature is raised to 80°C, and after 12 h of heat preservation, the temperature is lowered and the pressure is released. The reaction liquid is filtered by inserting the reaction kettle into the bottom filter for collection.

[0051] 4) Using reduced pressure distillation to remove the solvent, impurities, etc. from the reaction solution obtained in step 3), the distillation column bottom temperature is 140℃; the column top temperature is 85℃, the column internal pressure is 10Pa absolute pressure; the distillation column theoretical plate number is 20 pieces. Collect 1,12-dodecanediol with purity >99%, the product yield is 99.1%.

[0052] Example 3

[0053] The method for preparing 1,12-dodecanediol according to the present application:

[0054] 1) Using a three-necked flask, weigh 20g cyclododecatriene, 200g methanol and 4g pure water, mix uniformly and then place in a circulating cooling bath for standby, and lower the circulating cooling bath temperature.

[0055] 2) After the mixed solution in the three-necked flask is cooled to -20℃, introduce the oxygen / ozone mixed gas with ozone purity of 30mg / L, the gas flow rate is 3L / min, the reaction pressure is 2MPaA, the reaction is carried out for 1.45h, and after 7.83g ozone is introduced in total, stop introducing the mixed gas.

[0056] 3) Transfer the ozonization reaction solution obtained in step 2) to a reaction kettle, add Raney nickel catalyst (0.2g), seal the kettle cover, nitrogen flush to 4MPaA for pressure test, confirm that the autoclave sealing property is good, then use nitrogen to replace 3 times and hydrogen to replace 3 times, and then empty the hydrogen in the reactor, hydrogen charge to 4MPaA, heat to 100℃, keep warm for 16h, then cool and release pressure, and collect the reaction solution by filtering through a filter inserted at the bottom of the reactor.

[0057] 4) Using reduced pressure distillation to remove the solvent, impurities, etc. from the reaction solution obtained in step 3), the distillation column bottom temperature is 160℃; the column top temperature is 110℃, the column internal pressure is 100Pa absolute pressure; the distillation column theoretical plate number is 15 pieces. Collect 1,12-dodecanediol with purity >99%, the product yield is 99.0%.

[0058] Example 4

[0059] The method for preparing 1,12-dodecanediol according to the present application:

[0060] 1) Using a three-necked flask, weigh 20g cyclododecatriene, 200g methanol and 4g pure water, mix uniformly and then place in a circulating cooling bath for standby, and lower the circulating cooling bath temperature.

[0061] 2) After the mixed solution in the three-necked flask is cooled to -20℃, introduce the oxygen / ozone mixed gas with ozone purity of 30mg / L, the gas flow rate is 3L / min, the reaction pressure is 2MPaA, the reaction is carried out for 1.45h, and after 7.83g ozone is introduced in total, stop introducing the mixed gas.

[0062] 3) The ozonization reaction solution obtained in step 2) was transferred to a reaction kettle, Raney nickel catalyst (1 g) was added, the kettle cover was sealed, nitrogen was purged to 2 MPa A, the pressure was checked for leakage, and the high-pressure kettle was confirmed to be well sealed. After using nitrogen to replace 3 times and hydrogen to replace 3 times, the reactor was emptied of hydrogen, hydrogen was charged to 3 MPa A, heated to 50°C, and held for 8 h. After cooling and pressure relief, the reaction solution was filtered through a filter inserted at the bottom of the reactor.

[0063] 4) The reaction solution obtained in step 3) was removed from the solvent, impurities, etc. using vacuum rectification, the rectification column bottom temperature was 150°C; the column top temperature was 100°C, the column internal pressure was 50 Pa absolute; the rectification column theoretical plate number was 18. Collect 1,12-dodecanediol with purity > 99%, product yield 98.9%.

[0064] Comparative Example 1

[0065] 1,12-dodecanediol was prepared according to the method of Example 1, except that the solvent methanol added in step 1) was replaced with alcohol water, and the rest was the same as Example 1. The product 1,12-dodecanediol was obtained, and the product yield was 24%.

[0066] Comparative Example 2

[0067] 1,12-dodecanediol was prepared according to the method of Example 1, except that no pure water was added in step 1), and the rest was the same as Example 1. The product 1,12-dodecanediol was obtained, and the product yield was 11%.

[0068] Comparative Example 3

[0069] 1,12-dodecanediol was prepared according to the method of Example 1, except that 1 g of pure water was added in step 1), and the rest was the same as Example 1. The product 1,12-dodecanediol was obtained, and the product yield was 10%.

Claims

1. A process for the preparation of 1, 12-dodecanediol, characterized in that, The method comprises the following steps: a) reacting ozone with cyclododecatriene in a water-containing solvent to obtain a reaction solution; b) adding Raney nickel catalyst into the reaction solution of step a) and carrying out reduction reaction under hydrogen atmosphere.

2. The production method according to claim 1, characterized by, In step a), the solvent is selected from one or more of inert aliphatic alkanes, aromatic hydrocarbons, ethers and alcohols which do not react with the raw material, preferably one or more of methanol, acetone and n-heptane; preferably, the amount of solvent is 1-20 times, preferably 4-10 times the mass of cyclododecatriene.

3. The production method according to claim 1 or 2, characterized by, In step a), the water in the water-containing solvent is 0.1-2 times, preferably 0.2-1 times the mass of cyclododecatriene.

4. The production method according to any one of claims 1 to 3, characterized by, In step a), ozone is continuously introduced into the reaction system, and the total amount of ozone is 1.0-1.5 times, preferably 1.1-1.3 times the molar amount of cyclododecatriene. Preferably, ozone is introduced into the reaction system using oxygen as the carrier gas, and the concentration of ozone is 10-50 mg / L, preferably 15-30 mg / L. Preferably, the flow rate of ozone is 0.1-5 L / min, preferably 0.5-3 L / min.

5. The method of any one of claims 1-4, wherein, In step a), the reaction temperature is -80℃ to 10℃, preferably -60℃ to -20℃; and the reaction pressure is 0.1-5 MPaA, preferably 0.1-2 MPaA.

6. The method of claim 1, wherein, In step b), the amount of Raney nickel catalyst is 0.5-10 wt%, preferably 1-5 wt% of the mass of cyclododecatriene.

7. The production method according to claim 1 or 6, characterized by, In step b), the hydrogenation reaction temperature is 30-120℃, preferably 50-100℃; the reaction pressure is 1-5 MPaA, preferably 2-4 MPaA; and the reaction time is 5-24 h, preferably 8-16 h.

8. The method of any one of claims 1-7, wherein, The preparation method further comprises step c): obtaining the reduction reaction solution of step b) and refining to obtain 1,12-dodecanediol product.

9. The production method according to claim 8, characterized by, In step c), the refining comprises a distillation column, the bottom temperature of the distillation column is 130-170℃, preferably 140-160℃; the top temperature is 80-130℃, preferably 85-110℃; the pressure in the column is 10-500 Pa, preferably 10-100 Pa; and the number of theoretical plates of the distillation column is 15-25, preferably 15-20.

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