Process for preparing cyclododecene

Abstract

The invention relates to a method for preparing cyclododecene, which comprises the following steps: contacting a raw material mixture containing 1, 5, 9-cyclododecatriene and a first solvent with a hydrogenation catalyst for hydrogenation reaction to obtain cyclododecene, wherein the hydrogenation catalyst comprises a carrier and an active component loaded on the carrier, the carrier is phosphorus modified alumina, and the active component is palladium. The method disclosed by the invention can realize high-efficiency and high-selectivity hydrogenation of cyclododecatriene under mild reaction conditions, and has industrial application prospects.

Description

Technical Field

[0001] This disclosure relates to a method for preparing cyclododecene. Background Technology

[0002] Cyclododecene is an important raw material and synthetic intermediate for the preparation of cyclododecone and its derivatives, such as macrocyclic musk and nylon 12. Currently, the synthesis of cyclododecene mainly involves the hydrogenation reaction of 1,5,9-cyclododecanetriene. However, the hydrogenation of 1,5,9-cyclododecanetriene is a complex process involving multiple catalytic conversions. During the entire reaction, in addition to cyclododecene, byproducts such as cyclododecadiene and cyclododecane are also produced. Therefore, controlling the rate of each step of the hydrogenation reaction of 1,5,9-cyclododecanetriene is key to improving the selectivity of cyclododecene, which is mainly achieved through catalyst design and process parameter optimization. Catalysts used for the synthesis of cyclododecene from 1,5,9-cyclododecanetriene include homogeneous and heterogeneous catalysts. Among them, heterogeneous catalysts have advantages such as easy catalyst recovery and low cost, but compared with homogeneous catalytic systems, both the feed conversion rate and the selectivity of cyclododecene are slightly lower.

[0003] Therefore, further improving the conversion rate and selectivity of heterogeneous catalytic hydrogenation of cyclododecanetriene to cyclododecene has become an urgent problem to be solved. Summary of the Invention

[0004] The purpose of this disclosure is to provide a method for preparing cyclododecene to improve the selectivity of cyclododecene.

[0005] To achieve the above objectives, this disclosure provides a method for preparing cyclododecene, the method comprising: A mixture of feedstocks containing 1,5,9-cyclododecanetriene and a first solvent is contacted with a hydrogenation catalyst to carry out a hydrogenation reaction to obtain cyclododecene. The hydrogenation catalyst comprises a support and an active component supported on the support, wherein the support is phosphorus-modified alumina and the active component is palladium.

[0006] Optionally, the weight ratio of the 1,5,9-cyclododecanetriene, the first solvent, and the hydrogenation catalyst is 1:(0.5~10):(0.008~0.05).

[0007] Optionally, the first solvent includes one or more of diacetone alcohol, ethanol, cyclohexane, benzene, and dioxane, preferably ethanol or a mixture of benzene and ethanol.

[0008] Optionally, the hydrogenation reaction is carried out in a batch reactor; and / or The conditions for the hydrogenation reaction include: a reaction temperature of 25~180℃ and a hydrogen partial pressure of 0.01~5MPa.

[0009] Optionally, in the hydrogenation catalyst, the phosphorus content is 0.5 to 10% by weight, based on the dry weight of the support.

[0010] Optionally, the palladium content in the hydrogenation catalyst is 0.1 to 8% by weight, based on the dry weight of the hydrogenation catalyst.

[0011] Optionally, the step of preparing the hydrogenation catalyst includes: An aluminum source, a phosphorus source, and a second solvent are mixed, and the resulting mixture is subjected to a first drying and a first calcination to obtain a carrier. The carrier is impregnated with a solution containing a palladium source to obtain an impregnated carrier; The impregnated support is aged at a pH of 7-9, and the solid product is collected and then subjected to a second drying and a second calcination to obtain the hydrogenation catalyst.

[0012] Optionally, the molar ratio of the aluminum source, the phosphorus source, and the second solvent is 1:(0.008~0.17):(0.8~7.2). The weight ratio of the carrier to the palladium source is 1:(0.0016~0.21).

[0013] Optionally, the aluminum source includes one or more of aluminum isopropoxide, sodium aluminate, and aluminum nitrate; The phosphorus source includes one or more of phosphoric acid, potassium dihydrogen phosphate, ammonium dihydrogen phosphate, sodium dihydrogen phosphate, and metal phosphides; The second solvent includes one or more of ethanol, water, and isopropanol; The palladium source includes one or more of palladium chloride, palladium nitrate, palladium acetate, chloropalladium acid, and ammonium chloropalladium.

[0014] Optionally, the mixing conditions include: a temperature of 20~60℃ and a time of 2~12h; The conditions for the first drying process include: a temperature of 60~150℃ and a time of 1~12h; The conditions for the first roasting include: a temperature of 250~750℃ and a time of 0.5~12h.

[0015] Optionally, the impregnation conditions include: a temperature of 20~100℃ and a time of 0.5~12h; The aging conditions include a time of 1 to 6 hours; The conditions for the second drying process include: a temperature of 60~150℃ and a time of 1~12h; The conditions for the second roasting include: a temperature of 400~750℃ and a time of 0.5~12h.

[0016] Optionally, the step of preparing the hydrogenation catalyst further includes: reducing and activating the hydrogenation catalyst under a hydrogen atmosphere; The conditions for reduction and activation include: a temperature of 100~500℃ and a time of 0.5~12h.

[0017] Through the above technical solution, this disclosure uses a special heterogeneous hydrogenation catalyst for the hydrogenation reaction of cyclododecanetriene. The hydrogenation catalyst uses phosphorus-modified alumina as a support and loads palladium active components. It has the advantages of high catalytic activity and selectivity, controllable catalyst structure, low preparation cost, non-corrosive to equipment, and easy separation and recovery. The method disclosed in this disclosure can achieve efficient and highly selective hydrogenation of cyclododecanetriene under mild reaction conditions and has promising industrial application prospects.

[0018] Other features and advantages of this disclosure will be described in detail in the following detailed description section. Detailed Implementation

[0019] The following provides a detailed description of specific embodiments of this disclosure. It should be understood that the specific embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit this disclosure.

[0020] This disclosure provides a method for preparing cyclododecene, the method comprising: contacting a mixture of raw materials containing 1,5,9-cyclododecanetriene and a first solvent with a hydrogenation catalyst to carry out a hydrogenation reaction to obtain cyclododecene; The hydrogenation catalyst comprises a support and an active component supported on the support, wherein the support is phosphorus-modified alumina and the active component is palladium (Pd).

[0021] In this method, the catalyst uses phosphorus-modified alumina as a support, which helps to weaken the interaction between the metal active component and the support, improve the dispersion of the active component palladium, and enhance catalytic activity and selectivity. The phosphorus content in the support can be adjusted within a certain range. Specifically, in the hydrogenation catalyst, based on the dry weight of the support, the phosphorus content can be 0.5-10% by weight, preferably 2-8% by weight. The alumina can be various common crystal forms of alumina, preferably γ-alumina.

[0022] The content of the active component can be adjusted within a certain range. In one specific embodiment, the palladium content in the hydrogenation catalyst, based on the dry weight of the hydrogenation catalyst, can be 0.1-8% by weight, preferably 0.5-4% by weight.

[0023] The catalyst disclosed herein possesses a suitable specific surface area and pore structure, which is beneficial for the efficient and selective hydrogenation reaction. It is particularly suitable for the hydrogenation of cyclododecanetriene to cyclododecene, exhibiting high catalytic activity and selectivity. Specifically, the specific surface area of ​​the catalyst can be 80~300 m². 2 / g, and the pore volume can be 0.2~2mL / g.

[0024] In one specific embodiment, the step of preparing the hydrogenation catalyst may include the following steps S1 to S3: S1. Mix the aluminum source, phosphorus source and second solvent, and subject the resulting mixture to first drying and first calcination to obtain a carrier; S2. The carrier is impregnated with a solution containing a palladium source to obtain an impregnated carrier; S3. The impregnated support is aged under conditions of pH 7-9, and the solid product is collected and then subjected to a second drying and a second calcination to obtain the hydrogenation catalyst.

[0025] In step S1, the amounts of the aluminum source, phosphorus source, and second solvent are adjusted to achieve the aforementioned ratio in the prepared hydrogenation catalyst. Specifically, the molar ratio of the aluminum source, phosphorus source, and second solvent can be 1:(0.008~0.17):(0.8~7.2), preferably 1:(0.03~0.13):(1.6~5.7). The aluminum source may include one or more of aluminum isopropoxide, sodium aluminate, and aluminum nitrate; the phosphorus source may include one or more of phosphoric acid, potassium dihydrogen phosphate, ammonium dihydrogen phosphate, sodium dihydrogen phosphate, and metal phosphides (such as aluminum phosphide, zinc phosphide, etc.); and the second solvent may include one or more of ethanol, water, and isopropanol. The mixing of the aluminum source, phosphorus source, and second solvent can be carried out under stirring conditions. Specifically, the mixing conditions may include a temperature of 20~60℃ and a time of 2~12h.

[0026] The first drying conditions may include: a temperature of 60~150℃ and a time of 1~12h; the first calcination conditions may include: a temperature of 250~750℃ and a time of 0.5~12h.

[0027] In step S2, the ratio of the support to the palladium source solution is such that the prepared catalyst has the ratio described above. Specifically, the weight ratio of the support to the palladium source can be 1:(0.0016~0.21), preferably 1:(0.017~0.13). The palladium source may include one or more of palladium chloride, palladium nitrate, palladium acetate, palladium chloroacetic acid, and ammonium palladium chloroacetate.

[0028] The impregnation can be carried out under stirring conditions. Specifically, the impregnation conditions may include a temperature of 20~100℃ and a time of 0.5~12h. In step S3, the impregnated carrier can be brought to the desired pH value by adding a pH adjuster (such as an acid or alkali). The aging conditions may include a time of 1 to 6 hours; the second drying conditions may include a temperature of 60 to 150°C and a time of 1 to 12 hours; the second calcination conditions may include a temperature of 400 to 750°C and a time of 0.5 to 12 hours.

[0029] To further improve the catalytic activity of the hydrogenation catalyst, the step of preparing the hydrogenation catalyst may further include: S4. The hydrogenation catalyst is reduced and activated under a hydrogen atmosphere.

[0030] Specifically, the conditions for reduction and activation may include: a temperature of 100~500℃ and a time of 0.5~12h.

[0031] The hydrogenation catalyst preparation steps of the above embodiments are simple and easy to operate, and the prepared hydrogenation catalyst has good catalytic activity and stability.

[0032] According to this disclosure, the English name of the 1,5,9-cyclododecanetriene is Cyclododecatriene, and the CAS number is 4904-61-4; the English name of the cyclododecene is Cyclododecene, and the CAS number is 1501-82-2. They can be used as intermediates to synthesize high-value-added products, such as nylon 12.

[0033] The first solvent may include one or more of diacetone alcohol, ethanol, cyclohexane, benzene and dioxane. In a preferred embodiment, the first solvent is ethanol or a mixture of benzene and ethanol. When the first solvent is a mixture of benzene and ethanol, the weight ratio of benzene to ethanol may be 1:(0.5~5).

[0034] The hydrogenation catalyst can achieve highly selective hydrogenation to cyclododecene even with a small amount. Specifically, the weight ratio of the 1,5,9-cyclododecanetriene, the first solvent, and the hydrogenation catalyst can be 1:(0.5~10):(0.008~0.05), and the preferred weight ratio of the 1,5,9-cyclododecanetriene to the hydrogenation catalyst is 1:(0.011~0.03).

[0035] The hydrogenation reaction can be carried out in a reactor commonly used in the art. In a preferred embodiment, the hydrogenation reaction is carried out in a batch reactor. Further, the conditions for the hydrogenation reaction may include: a reaction temperature of 25~180℃, preferably 80~160℃; and a hydrogen partial pressure of 0.01~5MPa, preferably 0.01~1MPa.

[0036] The present disclosure will be described in detail below through examples, but it is not intended to limit the present disclosure.

[0037] The reagents used in the following examples are commercially available and of analytical grade.

[0038] In the examples, the component content of the catalyst was detected by X-ray fluorescence spectroscopy under the following conditions: tungsten-palladium target, excitation voltage 40 kV, and excitation current 250 mA.

[0039] The specific surface area and pore volume of the catalyst were determined using gas adsorption. The testing conditions were vacuum at 300℃ for 4 hours to purify the sample. The adsorption and desorption of nitrogen were tested under different relative pressures at a liquid nitrogen temperature of -196℃.

[0040] Example 1 (1) Aluminum isopropoxide, phosphoric acid, and solvent ethanol were mixed in a molar ratio of 1:0.008:4.3 and stirred at 20°C for 10 h. The mixture was then transferred to an oven and dried at 120°C for 12 h, followed by calcination at 550°C for 3 h to obtain the support. The support was dispersed in a palladium chloride aqueous solution (5 g / L) (support to palladium chloride weight ratio 1:0.03) and impregnated at 25°C for 12 h. Then, 0.1 mol / L NaOH aqueous solution was added dropwise until the pH of the slurry reached 9. The mixture was magnetically stirred and aged for 4 h, filtered, and washed with deionized water until Cl... - Concentration less than 10 -6 M was then dried in an oven at 120°C for 12 hours, ground, and then calcined in a muffle furnace at 550°C for 3 hours. The calcined catalyst was placed in a tube furnace and reduced and activated at 250°C in an H2 atmosphere for 2 hours to obtain hydrogenation catalyst C1, the composition, specific surface area, and pore volume of which are listed in Table 1.

[0041] (2) 1,5,9-Cyclododecanetriene, anhydrous ethanol, and hydrogenation catalyst C1 (weight ratio 1:5:0.015) were added to a 300 mL autoclave. The autoclave temperature was set to 80 °C, H2 was introduced until the hydrogen partial pressure reached 0.1 MPa and maintained, the stirring speed was 500 r / min, and the reaction time was 1 h. The weight percentage of cyclododecanetriene in the system before and after the reaction was determined by an Agilent 8890 gas chromatograph. The ratio of the difference in content to the content before the reaction was the conversion rate of cyclododecanetriene. The ratio of the weight percentage of cyclododecanetriene after the reaction to the conversion rate of cyclododecanetriene can represent the selectivity of the catalyst for cyclododecanetriene. The results are listed in Table 2.

[0042] Example 2 The hydrogenation catalyst was prepared according to the method of Example 1 and used for the hydrogenation reaction of 1,5,9-cyclododecanetriene. The difference is that in step (1), the molar ratio of aluminum isopropoxide to phosphoric acid was 1:0.08, and catalyst C2 was prepared. The catalyst composition, specific surface area and pore volume are listed in Table 1, and the reaction results are listed in Table 2.

[0043] Example 3 The hydrogenation catalyst was prepared according to the method of Example 1 and used for the hydrogenation reaction of 1,5,9-cyclododecanetriene. The difference is that in step (1), the molar ratio of aluminum isopropoxide to phosphoric acid was 1:0.16, and catalyst C3 was prepared. The catalyst composition, specific surface area and pore volume are listed in Table 1, and the reaction results are listed in Table 2.

[0044] Example 4 The hydrogenation catalyst was prepared according to the method of Example 2 and used for the hydrogenation reaction of 1,5,9-cyclododecanetriene. The difference is that in step (1), the weight ratio of the support to palladium chloride was 1:0.067, and catalyst C4 was prepared. The catalyst composition, specific surface area and pore volume are listed in Table 1, and the reaction results are listed in Table 2.

[0045] Example 5 The hydrogenation catalyst was prepared according to the method of Example 2 and used for the hydrogenation reaction of 1,5,9-cyclododecanetriene. The difference is that in step (1), the weight ratio of the support to palladium chloride was 1:0.017, and catalyst C5 was prepared. The catalyst composition, specific surface area and pore volume are listed in Table 1, and the reaction results are listed in Table 2.

[0046] Example 6 The hydrogenation catalyst was prepared according to the method of Example 2 and used for the hydrogenation reaction of 1,5,9-cyclododecanetriene. The difference is that in step (1), the weight ratio of the support to palladium chloride was 1:0.0017, and catalyst C6 was prepared. The catalyst composition, specific surface area and pore volume are listed in Table 1, and the reaction results are listed in Table 2.

[0047] Example 7 The hydrogenation catalyst was prepared according to the method of Example 2 and used for the hydrogenation reaction of 1,5,9-cyclododecanetriene. The difference is that in step (1), the weight ratio of the support to palladium chloride was 1:0.013, and catalyst C7 was prepared. The catalyst composition, specific surface area and pore volume are listed in Table 1, and the reaction results are listed in Table 2.

[0048] Example 8 The hydrogenation catalyst was prepared according to the method of Example 5 and used for the hydrogenation reaction of 1,5,9-cyclododecanetriene. The difference is that in step (2), the hydrogenation reaction conditions were: the temperature was 60°C. The reaction results are listed in Table 2.

[0049] Example 9 The hydrogenation catalyst was prepared according to the method of Example 5 and used for the hydrogenation reaction of 1,5,9-cyclododecanetriene. The difference is that in step (2), the hydrogenation reaction conditions were: the temperature was 100°C. The reaction results are listed in Table 2.

[0050] Example 10 The hydrogenation catalyst was prepared according to the method of Example 5 and used for the hydrogenation reaction of 1,5,9-cyclododecanetriene. The difference is that in step (2), the hydrogenation reaction conditions are: hydrogen partial pressure of 0.05 MPa. The reaction results are listed in Table 2.

[0051] Example 11 The hydrogenation catalyst was prepared according to the method of Example 5 and used for the hydrogenation reaction of 1,5,9-cyclododecanetriene, except that in step (2), the mixed solvents benzene and ethanol (weight ratio 1:1) were used instead of anhydrous ethanol. The reaction results are listed in Table 2.

[0052] Example 12 The hydrogenation catalyst was prepared according to the method of Example 5 and used for the hydrogenation reaction of 1,5,9-cyclododecanetriene, except that in step (2), the solvent dioxane was used instead of anhydrous ethanol. The reaction results are listed in Table 2.

[0053] Example 13 The hydrogenation catalyst was prepared according to the method of Example 5 and used for the hydrogenation reaction of 1,5,9-cyclododecanetriene, except that in step (2), the weight ratio of 1,5,9-cyclododecanetriene, anhydrous ethanol and hydrogenation catalyst C1 was 1:5:0.008. The reaction results are listed in Table 2.

[0054] Comparative Example 1 The hydrogenation catalyst was prepared according to the method of Example 5 and used for the hydrogenation reaction of 1,5,9-cyclododecanetriene, except that phosphoric acid was not added in step (1), and catalyst D1 was prepared. The composition of the catalyst is listed in Table 1 and the reaction results are listed in Table 2.

[0055] Comparative Example 2 The hydrogenation catalyst was prepared according to the method of Example 5 and used for the hydrogenation reaction of 1,5,9-cyclododecanetriene. The difference is that in step (1), the same amount of rhodium chloride was used to replace palladium chloride to prepare catalyst D2. The catalyst composition is listed in Table 1 and the reaction results are listed in Table 2.

[0056] Table 1

[0057] Table 2

[0058] As shown in Table 2, the catalyst disclosed herein can achieve efficient and highly selective hydrogenation of cyclododecanetriene to cyclododecene under mild reaction conditions.

[0059] The preferred embodiments of this disclosure have been described in detail above. However, this disclosure is not limited to the specific details of the above embodiments. Within the scope of the technical concept of this disclosure, various simple modifications can be made to the technical solutions of this disclosure, and these simple modifications all fall within the protection scope of this disclosure.

[0060] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, this disclosure will not describe the various possible combinations separately.

[0061] Furthermore, various different embodiments of this disclosure can be combined in any way, as long as they do not violate the spirit of this disclosure, they should also be regarded as the content disclosed in this disclosure.

Claims

1. A method for preparing cyclododecene, characterized in that, The method includes: A mixture of feedstocks containing 1,5,9-cyclododecanetriene and a first solvent is contacted with a hydrogenation catalyst to carry out a hydrogenation reaction to obtain cyclododecene. The hydrogenation catalyst comprises a support and an active component supported on the support, wherein the support is phosphorus-modified alumina and the active component is palladium.

2. The method according to claim 1, wherein, The weight ratio of the 1,5,9-cyclododecanetriene, the first solvent, and the hydrogenation catalyst is 1:(0.5~10):(0.008~0.05).

3. The method according to claim 1, wherein, The first solvent includes one or more of diacetone alcohol, ethanol, cyclohexane, benzene and dioxane, preferably ethanol or a mixture of benzene and ethanol.

4. The method according to claim 1, wherein, The hydrogenation reaction is carried out in a batch reactor; and / or The conditions for the hydrogenation reaction include: a reaction temperature of 25~180℃ and a hydrogen partial pressure of 0.01~5MPa.

5. The method according to claim 1, wherein, In the hydrogenation catalyst, the phosphorus content is 0.5 to 10% by weight, based on the dry weight of the support.

6. The method according to claim 1, wherein, In the hydrogenation catalyst, the palladium content is 0.1 to 8% by weight, based on the dry weight of the hydrogenation catalyst.

7. The method according to claim 1, wherein, The steps for preparing the hydrogenation catalyst include: An aluminum source, a phosphorus source, and a second solvent are mixed, and the resulting mixture is subjected to a first drying and a first calcination to obtain a carrier. The carrier is impregnated with a solution containing a palladium source to obtain an impregnated carrier; The impregnated support is aged at a pH of 7-9, and the solid product is collected and then subjected to a second drying and a second calcination to obtain the hydrogenation catalyst.

8. The method according to claim 7, wherein, The molar ratio of the aluminum source, the phosphorus source, and the second solvent is 1:(0.008~0.17):(0.8~7.2). The weight ratio of the carrier to the palladium source is 1:(0.0016~0.21).

9. The method according to claim 7, wherein, The aluminum source includes one or more of aluminum isopropoxide, sodium aluminate, and aluminum nitrate. The phosphorus source includes one or more of phosphoric acid, potassium dihydrogen phosphate, ammonium dihydrogen phosphate, sodium dihydrogen phosphate, and metal phosphides; The second solvent includes one or more of ethanol, water, and isopropanol; The palladium source includes one or more of palladium chloride, palladium nitrate, palladium acetate, chloropalladium acid, and ammonium chloropalladium.

10. The method according to claim 7, wherein, The mixing conditions include: a temperature of 20~60℃ and a time of 2~12h; The conditions for the first drying process include: a temperature of 60~150℃ and a time of 1~12h; The conditions for the first roasting include: a temperature of 250~750℃ and a time of 0.5~12h.

11. The method according to claim 7, wherein, The impregnation conditions include: a temperature of 20~100℃ and a time of 0.5~12h; The aging conditions include a time of 1 to 6 hours; The conditions for the second drying process include: a temperature of 60~150℃ and a time of 1~12h; The conditions for the second roasting include: a temperature of 400~750℃ and a time of 0.5~12h.

12. The method according to claim 7, wherein, The step of preparing the hydrogenation catalyst further includes: reducing and activating the hydrogenation catalyst under a hydrogen atmosphere; The conditions for reduction and activation include: a temperature of 100~500℃ and a time of 0.5~12h.

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