A method for synthesizing ethyl (E)-2-(Z)-4-decadienoate

Abstract

This application belongs to the technical field of organic synthesis, and specifically relates to a method for synthesizing ethyl (E)-2-(Z)-4-decadienoate, which comprises the following steps: S1. Mix an alkaline catalyst with solvent A and cool it, then add triethyl phosphonoacetate and stir evenly, add 2-octanal, reflux and react at 70-80 °C for 20-26 h. After the reaction is completed, cool it to room temperature, add water and stir, separate the liquid, and after multiple extractions, recover the solvent and obtain intermediate 1 by flash distillation separation; S2. Mix intermediate 1 with a nano-catalyst, add solvent B, introduce hydrogen under the protection of an inert gas, and carry out a hydrogenation reaction at 30-40 °C and a hydrogen pressure of 1-5 MPa. After the reaction is completed, filter and separate to obtain ethyl (E)-2-(Z)-4-decadienoate; the nano-catalyst is a hollow nano Ru-Ni catalyst. This application effectively improves the yield of the product ethyl (E)-2-(Z)-4-decadienoate by using the hollow nano Ru-Ni catalyst.

Description

Technical Field

[0001] This application belongs to the technical field of organic synthesis, and specifically relates to a method for synthesizing ethyl (E,Z)-2,4-decadienoate. Background Art

[0002] Ethyl (E,Z)-2,4-decadienoate is a polyunsaturated fatty acid with a special conjugated double bond structure. It has a sharp aroma of fruits such as pears and apples and naturally exists in plants such as apples, Bartlett pears, and Concord grapes. It is the aroma component of these fruits and is a new type of edible spice, which is widely used in the food industry. In addition, due to the special fragrance of (E,Z)-2,4-decadienoate, it can also be combined with modified starch to make spice particles for laundry and cleaning.

[0003] Ethyl (E,Z)-2,4-decadienoate can also be used as a crop biochemical insecticide for pest control. Spraying ethyl (E,Z)-2,4-decadienoate on the leaf surface or using it in a polymerization dosing device, or using a plastic net containing ethyl (E,Z)-2,4-decadienoate to cover apple buds has a good effect on controlling codling moths, thus reducing the use of harmful pesticides. In addition, this substance also has outstanding performance in solving the pesticide resistance problem. Therefore, this substance has broad development and application prospects in the field of biological pesticides.

[0004] The existing methods for synthesizing ethyl (E,Z)-2,4-decadienoate mainly include:

[0005] Takeda et al. reported a method for preparing ethyl (E,Z)-2,4-decadienoate using allene (Organic Synthesis, 1993, 8, 251). First, alkynol was obtained by reacting n-hexanol with acetylene, and then a Claisen rearrangement reaction with triethyl orthoacetate under propionic acid conditions to obtain an intermediate with an allene structure. The intermediate was isomerized under alumina conditions to obtain ethyl (E,Z)-2,4-decadienoate. The overall yield of this reaction route is 70%, but the reaction temperature is relatively high. The temperature of the first step is about 150 °C, and the isomerization reaction of the second step requires 200 °C. In addition, ethanol generated during the reaction needs to be continuously removed and triethyl orthoformate needs to be added, resulting in poor reaction continuity and high energy consumption.

[0006] Normant et al. used 1-bromoheptene as the starting material. After making it into a metal copper salt, it was reacted with propargylate to prepare ethyl (E,Z)-2,4-decadienoate (Tetrahedron, 1980, 36, 1961). The overall yield of this reaction route is 65%, but the preparation of the organocopper reagent is relatively complex and requires reaction under anhydrous and anaerobic conditions. In addition, the purity of the product obtained by this method is about 92% and contains isomers, which requires multiple separation and purification steps.

[0007] Therefore, there are still problems in the existing synthesis process of ethyl (E)-2-(Z)-4-decadienoate, such as complex preparation process and low reaction yield. SUMMARY OF THE INVENTION

[0008] In order to improve the yield of the product, reduce the cost and simplify the operation, the present application proposes a synthesis method of ethyl (E)-2-(Z)-4-decadienoate.

[0009] The technical solution of the present application is as follows:

[0010] A synthesis method of ethyl (E)-2-(Z)-4-decadienoate, comprising the following steps:

[0011] S1. Mix an alkaline catalyst with solvent A and cool, then add triethyl phosphonoacetate and stir evenly, add 2-octanal, reflux at 70 - 80 °C for 20 - 26 h, after the reaction is completed, cool to room temperature, add water, stir, separate the liquid, after multiple extractions, recover the solvent, and obtain intermediate 1 by flash distillation separation;

[0012] S2. Mix intermediate 1 with a nanocatalyst, add solvent B, introduce hydrogen under the protection of an inert gas, and carry out a hydrogenation reaction at 30 - 40 °C and a hydrogen pressure of 1 - 5 MPa. After the reaction is completed, filter and separate to obtain ethyl (E)-2-(Z)-4-decadienoate;

[0013] The nanocatalyst is a hollow nanoscale Ru-Ni catalyst.

[0014] By adopting the above technical solution, 2-octanal reacts with triethyl phosphonoacetate under the action of an alkaline catalyst through the Wittig reaction to obtain intermediate ethyl 4-ynyl-(E)-2-decenoate, and intermediate ethyl 4-ynyl-(E)-2-decenoate is hydrogenated in the presence of a hollow nanoscale Ru-Ni catalyst to obtain ethyl (E)-2-(Z)-4-decadienoate. By using a hollow nanoscale Ru-Ni catalyst, its mesoporous structure enables the catalytic material to have an extremely high specific surface area, which is conducive to the adsorption and diffusion of reactant molecules on the catalyst surface, thereby increasing the rate of the catalytic reaction. The Ru-Ni bimetal shows higher activity, selectivity and stability in the catalytic reaction, thus significantly improving the yield of the product.

[0015] Preferably, the alkaline catalyst is one of sodium hydride, sodium hydroxide, sodium amide or sodium ethoxide.

[0016] Preferably, the molar ratio of the alkaline catalyst, triethyl phosphonoacetate and 2-octanal is 0.5 - 1:0.5 - 2:1.

[0017] Preferably, the solvent A is one of ethanol, methanol, tetrahydrofuran or isopropanol.

[0018] Preferably, the solvent B is one of cyclohexane, dimethyl ether or tetrahydrofuran.

[0019] Preferably, the mass ratio of the intermediate 1 to the nanocatalyst is 1:0.2 - 0.7.

[0020] By adopting the above technical solution, controlling the ratio of the reactant to the nanocatalyst can optimize the quantity and quality of the active sites on the catalyst surface, thereby enhancing the adsorption and conversion capabilities of the catalyst for the reactant and avoiding the increase in side reactions caused by excessive catalyst.

[0021] Preferably, the hollow nanoscale Ru-Ni catalyst is composed of the following raw materials in parts by weight: 0.1 - 0.3 part of nickel acetate tetrahydrate, 0.1 - 0.3 part of ruthenium(III) chloride trihydrate, 24 - 30 parts of ethanol, and 1 - 3 parts of hollow nanomaterials.

[0022] Preferably, the preparation method of the hollow nanoscale Ru-Ni catalyst comprises the following steps:

[0023] Ultrasonically disperse the hollow nanomaterials in ethanol, then add nickel acetate tetrahydrate and ruthenium(III) chloride trihydrate, disperse by ultrasonic treatment, and stir at room temperature for 4 - 6 h; then remove the ethanol, dry at room temperature, and calcine the solid product in a hydrogen-containing mixed gas atmosphere to obtain a stable hollow nanoscale Ru-Ni catalyst.

[0024] Preferably, the hollow nanomaterials are composed of the following raw materials in parts by weight: 0.125 - 0.25 part of cetyltrimethylammonium, 35 - 70 parts of water, 12 - 24 parts of ethanol, 0.15 - 0.28 part of ethylenediamine, 0.16 - 0.3 part of resorcinol, 0.24 - 0.48 part of formaldehyde with a mass fraction of 37%, and 0.6 - 1.2 parts of tetraethyl orthosilicate.

[0025] Preferably, the preparation method of the hollow nanomaterials comprises the following steps:

[0026] Dissolve a part of cetyltrimethylammonium in a mixed solution of water and ethanol, add ethylenediamine, stir evenly, add resorcinol, stir evenly again, add formaldehyde with a mass fraction of 37% to the mixed solution, stir at room temperature for 2 - 3 h to form spheres; then add the remaining cetyltrimethylammonium and tetraethyl orthosilicate, stir at room temperature for 4 - 6 h, perform centrifugal separation, washing and drying, and finally transfer the obtained solid to be calcined under argon protection to obtain the hollow nanomaterials.

[0027] Compared with the prior art, the present application has the following beneficial effects:

[0028] This application uses a hollow nano Ru-Ni catalyst. Its mesoporous structure endows the catalytic material with an extremely high specific surface area, which is conducive to the adsorption and diffusion of reactant molecules on the catalyst surface, thereby increasing the rate of the catalytic reaction. The Ru-Ni bimetal exhibits higher activity, selectivity, and stability in the catalytic reaction, thus significantly increasing the yield of the product ethyl trans-2-cis-4-decadienoate. Detailed implementation mode

[0029] The following further elaborates on this application in conjunction with examples.

[0030] Preparation Example 1

[0031] T1. Dissolve 0.12 g of cetyltrimethylammonium in a mixed solution of 35 g of water and 12 g of ethanol. After stirring at room temperature for 30 min, slowly add 0.15 g of ethylenediamine. After stirring for another 20 min, add 0.16 g of resorcinol and continue stirring for 20 min. Then add 0.24 g of formaldehyde with a mass fraction of 37% to the mixed solution and stir at room temperature for 2 h to form spheres. Subsequently, add the remaining 0.005 g of cetyltrimethylammonium and 0.6 g of tetraethyl orthosilicate, stir at room temperature for 4 h, centrifuge the resulting solution, wash it twice with water and ethanol respectively, dry it at room temperature for 2 days, and finally transfer the obtained solid to a tubular furnace and calcine it under argon protection. Raise the temperature of the tubular furnace from room temperature to 900 °C at a rate of 5 °C / min and hold for 3 h. Finally, collect the obtained powder, which is the hollow nano material.

[0032] T2. Ultrasonically disperse 1 g of the hollow nano material prepared in T1 in 24 g of ethanol, then add 0.1 g of nickel acetate tetrahydrate and 0.1 g of ruthenium(III) chloride trihydrate, and disperse them by ultrasonic treatment for 30 min. Stir at room temperature for 4 h, remove ethanol through a rotary evaporator, dry at room temperature, transfer the solid product to a tubular furnace, and calcine it in a mixed gas atmosphere containing 15% hydrogen. Raise the temperature of the tubular furnace from room temperature to 300 °C at a rate of 2 °C / min and hold for 2 h. Finally, obtain a stable hollow nano Ru-Ni catalyst.

[0033] Preparation Example 2

[0034] T1. Dissolve 0.19 g of cetyltrimethylammonium in a mixed solution of 52.5 g of water and 18 g of ethanol. After stirring at room temperature for 35 min, slowly add 0.21 g of ethylenediamine. After stirring for another 25 min, add 0.23 g of resorcinol. After continuing to stir for 25 min, add 0.36 g of formaldehyde with a mass fraction of 37% to the mixed solution and stir at room temperature for 2.5 h to form spheres. Subsequently, add the remaining 0.01 g of cetyltrimethylammonium and 0.9 g of tetraethyl orthosilicate, stir at room temperature for 5 h, centrifuge the obtained solution, wash it twice with water and ethanol respectively, dry it at room temperature for 2 days, and finally transfer the obtained solid to a tube furnace and calcine it under argon protection. Raise the temperature of the tube furnace from room temperature to 950 °C at a heating rate of 5 °C / min and hold for 4 h. Finally, collect the obtained powder, which is the hollow nanomaterial;

[0035] T2. Ultrasonically disperse 2 g of the hollow nanomaterial prepared in T1 in 27 g of ethanol, then add 0.2 g of nickel acetate tetrahydrate and 0.2 g of ruthenium(III) chloride trihydrate, and disperse them by ultrasonic treatment for 35 min. Stir at room temperature for 5 h, remove ethanol by a rotary evaporator, dry at room temperature, transfer the solid product to a tube furnace, and calcine it in a mixed gas atmosphere containing 15% hydrogen. Raise the temperature of the tube furnace from room temperature to 400 °C at a heating rate of 2 °C / min and hold for 3 h. Finally, obtain a stable hollow nanoscale Ru-Ni catalyst.

[0036] Preparation Example III

[0037] T1. Dissolve 0.22 g of cetyltrimethylammonium in a mixed solution of 70 g of water and 24 g of ethanol. After stirring at room temperature for 40 min, slowly add 0.28 g of ethylenediamine. After stirring for another 30 min, add 0.3 g of resorcinol. After continuing to stir for 30 min, add 0.48 g of formaldehyde with a mass fraction of 37% to the mixed solution and stir at room temperature for 3 h to form spheres. Subsequently, add the remaining 0.03 g of cetyltrimethylammonium and 1.2 g of tetraethyl orthosilicate, stir at room temperature for 6 h, centrifuge the obtained solution, wash it twice with water and ethanol respectively, dry it at room temperature for 2 days, and finally transfer the obtained solid to a tube furnace and calcine it under argon protection. Raise the temperature of the tube furnace from room temperature to 1000 °C at a heating rate of 5 °C / min and hold for 5 h. Finally, collect the obtained powder, which is the hollow nanomaterial;

[0038] T2. Ultrasonically disperse 3 g of the hollow nanomaterial prepared in T1 in 30 g of ethanol, then add 0.3 g of nickel acetate tetrahydrate and 0.3 g of ruthenium(III) chloride trihydrate, and disperse by ultrasonic treatment for 40 min. Stir at room temperature for 6 h, remove ethanol by a rotary evaporator, and after drying at room temperature, transfer the solid product to a tube furnace and calcine it in a mixed gas atmosphere containing 15% hydrogen. Raise the temperature of the tube furnace from room temperature to 500 °C at a heating rate of 2 °C / min and hold for 4 h to finally obtain a stable hollow nanoscale Ru-Ni catalyst.

[0039] Example 1

[0040] S1. Under anhydrous conditions, add 3.4 g of sodium ethoxide and 500 g of tetrahydrofuran to a reaction kettle and cool to 0 °C. Slowly drop 11.21 g of triethyl phosphonoacetate into the reaction kettle under stirring conditions, keep the temperature and stir for 30 min. Subsequently, slowly add 12.42 g of 2-octanal to the reaction solution. After adding, raise the temperature to 70 °C and reflux for 20 h. Monitor the reaction by GC until it is complete. After cooling to room temperature, add 100 mL of water and stir for 30 min. Separate the liquid. The aqueous phase is extracted twice with 50 g of ethyl acetate each time. Combine the organic phases, recover the solvent under negative pressure, and perform flash separation to obtain Intermediate 1;

[0041] S2. Add 30 g of Intermediate 1 prepared in S1 and 6 g of the hollow nanoscale Ru-Ni catalyst prepared in Preparation Example 1 to a hydrogenation reaction kettle, and add 50 mL of cyclohexane as a solvent to the reaction kettle. Protect the system by nitrogen replacement, and then replace it with hydrogen three times. Then carry out a hydrogenation reaction at 30 °C and a hydrogen pressure of 1.0 MPa for 12 h. After the reaction is completed, filter the system to remove insoluble substances, collect the filtrate, recover the solvent, and then perform column chromatography separation to obtain ethyl (E)-2-(Z)-4-decadienoate.

[0042] Example 2

[0043] S1. Under anhydrous conditions, add 1.2 g of sodium hydride and 500 g of ethanol to a reaction kettle and cool to 0 °C. Slowly drop 11.21 g of triethyl phosphonoacetate into the reaction kettle under stirring conditions, keep the temperature and stir for 35 min. Subsequently, slowly add 12.42 g of 2-octanal to the reaction solution. After adding, raise the temperature to 75 °C and reflux for 23 h. Monitor the reaction by GC until it is complete. After cooling to room temperature, add 110 mL of water and stir for 35 min. Separate the liquid. The aqueous phase is extracted twice with 50 g of ethyl acetate each time. Combine the organic phases, recover the solvent under negative pressure, and perform flash separation to obtain Intermediate 1;

[0044] S2. Add 30 g of Intermediate 1 prepared from S1 and 6 g of the hollow nano Ru-Ni catalyst prepared in Preparation Example 1 into a hydrogenation reactor, add 50 mL of dimethyl ether as a solvent into the reactor, displace the system with nitrogen for protection, then displace it with hydrogen three times, and then carry out a hydrogenation reaction at 35 °C and a hydrogen pressure of 3.0 MPa for 14 h. After the reaction is completed, filter the system to remove insoluble substances, collect the filtrate, recover the solvent and then carry out column chromatography separation to obtain ethyl trans-2-cis-4-decadienoate.

[0045] Example 3

[0046] S1. Under anhydrous conditions, add 1.95 g of sodium amide and 500 g of isopropanol into a reactor and cool it to 0 °C. Slowly drop 11.21 g of triethyl phosphonoacetate into the reactor under stirring conditions, keep the temperature and stir for 40 min. Then slowly add 12.42 g of 2-octanal into the reaction solution. After adding, raise the temperature to 80 °C and reflux for 26 h. Monitor the reaction by GC until it is complete. After cooling to room temperature, add 120 mL of water and stir for 40 min. Separate the liquid. The aqueous phase is extracted twice with 50 g of ethyl acetate each time. Combine the organic phases, recover the solvent under negative pressure, and carry out flash separation to obtain Intermediate 1;

[0047] S2. Add 30 g of Intermediate 1 prepared from S1 and 6 g of the hollow nano Ru-Ni catalyst prepared in Preparation Example 1 into a hydrogenation reactor, add 50 mL of tetrahydrofuran as a solvent into the reactor, displace the system with nitrogen for protection, then displace it with hydrogen three times, and then carry out a hydrogenation reaction at 40 °C and a hydrogen pressure of 5.0 MPa for 16 h. After the reaction is completed, filter the system to remove insoluble substances, collect the filtrate, recover the solvent and then carry out column chromatography separation to obtain ethyl trans-2-cis-4-decadienoate.

[0048] Example 4

[0049] S1. Under anhydrous conditions, add 5.1 g of sodium ethoxide and 500 g of tetrahydrofuran into a reactor and cool it to 0 °C. Slowly drop 22.42 g of triethyl phosphonoacetate into the reactor under stirring conditions, keep the temperature and stir for 30 min. Then slowly add 12.42 g of 2-octanal into the reaction solution. After adding, raise the temperature to 70 °C and reflux for 20 h. Monitor the reaction by GC until it is complete. After cooling to room temperature, add 100 mL of water and stir for 30 min. Separate the liquid. The aqueous phase is extracted twice with 50 g of ethyl acetate each time. Combine the organic phases, recover the solvent under negative pressure, and carry out flash separation to obtain Intermediate 1;

[0050] S2. Add 30 g of Intermediate 1 prepared from S1 and 6 g of the hollow nano Ru-Ni catalyst prepared from Preparation Example 1 into a hydrogenation reactor, add 50 mL of cyclohexane into the reactor as a solvent, displace and protect the system with nitrogen, then displace with hydrogen three times, and then carry out a hydrogenation reaction at 30 °C and a hydrogen pressure of 1.0 MPa for 12 h. After the reaction is completed, filter the system to remove insoluble substances, collect the filtrate, recover the solvent and then carry out column chromatography separation to obtain ethyl trans-2-cis-4-decadienoate.

[0051] Example 5

[0052] S1. Under anhydrous conditions, add 6.8 g of sodium ethoxide and 500 g of tetrahydrofuran into a reactor and cool to 0 °C. Slowly drop 44.84 g of triethyl phosphonoacetate into the reactor under stirring conditions, keep stirring for 30 min, then slowly add 12.42 g of 2-octanal into the reaction solution. After adding, raise the temperature to 70 °C and reflux for 20 h. Monitor the reaction by GC until it is complete. After cooling to room temperature, add 100 mL of water and stir for 30 min. Separate the layers. The aqueous phase is extracted twice with 50 g of ethyl acetate each time. Combine the organic phases, recover the solvent under negative pressure, and carry out flash separation to obtain Intermediate 1;

[0053] S2. Add 30 g of Intermediate 1 prepared from S1 and 6 g of the hollow nano Ru-Ni catalyst prepared from Preparation Example 1 into a hydrogenation reactor, add 50 mL of cyclohexane into the reactor as a solvent, displace and protect the system with nitrogen, then displace with hydrogen three times, and then carry out a hydrogenation reaction at 30 °C and a hydrogen pressure of 1.0 MPa for 12 h. After the reaction is completed, filter the system to remove insoluble substances, collect the filtrate, recover the solvent and then carry out column chromatography separation to obtain ethyl trans-2-cis-4-decadienoate.

[0054] Example 6

[0055] S1. Under anhydrous conditions, add 1.2 g of sodium ethoxide and 500 g of tetrahydrofuran into a reactor and cool to 0 °C. Slowly drop 2.242 g of triethyl phosphonoacetate into the reactor under stirring conditions, keep stirring for 30 min, then slowly add 12.42 g of 2-octanal into the reaction solution. After adding, raise the temperature to 70 °C and reflux for 20 h. Monitor the reaction by GC until it is complete. After cooling to room temperature, add 100 mL of water and stir for 30 min. Separate the layers. The aqueous phase is extracted twice with 50 g of ethyl acetate each time. Combine the organic phases, recover the solvent under negative pressure, and carry out flash separation to obtain Intermediate 1;

[0056] S2. Add 30 g of Intermediate 1 prepared from S1 and 6 g of the hollow nano Ru-Ni catalyst prepared from Preparation Example 1 to a hydrogenation reactor, add 50 mL of cyclohexane to the reactor as a solvent, displace and protect the system with nitrogen, then displace with hydrogen three times, and then carry out a hydrogenation reaction at 30 °C and a hydrogen pressure of 1.0 MPa for 12 h. After the reaction is completed, filter the system to remove insoluble substances, collect the filtrate, recover the solvent and then carry out column chromatography separation to obtain ethyl trans-2-cis-4-decadienoate.

[0057] Example VII

[0058] S1. Add 13.6 g of sodium ethoxide and 500 g of tetrahydrofuran to a reactor under anhydrous conditions and cool to 0 °C. Slowly drop 67.26 g of triethyl phosphonoacetate into the reactor under stirring conditions, keep the temperature and stir for 30 min. Then slowly add 12.42 g of 2-octanal to the reaction solution. After adding, raise the temperature to 70 °C and reflux for 20 h. Monitor the reaction by GC until it is complete. After cooling to room temperature, add 100 mL of water and stir for 30 min. Separate the layers. The aqueous phase is extracted twice with 50 g of ethyl acetate each time. Combine the organic phases, recover the solvent under reduced pressure, and carry out flash separation to obtain Intermediate 1.

[0059] S2. Add 30 g of Intermediate 1 prepared from S1 and 6 g of the hollow nano Ru-Ni catalyst prepared from Preparation Example 1 to a hydrogenation reactor, add 50 mL of cyclohexane to the reactor as a solvent, displace and protect the system with nitrogen, then displace with hydrogen three times, and then carry out a hydrogenation reaction at 30 °C and a hydrogen pressure of 1.0 MPa for 12 h. After the reaction is completed, filter the system to remove insoluble substances, collect the filtrate, recover the solvent and then carry out column chromatography separation to obtain ethyl trans-2-cis-4-decadienoate.

[0060] Example VIII

[0061] The difference between Example VIII and Example I is that in S2 of Example VIII, the hollow nano Ru-Ni catalyst used is from Preparation Example 1 and the mass is 15 g.

[0062] Example IX

[0063] The difference between Example IX and Example I is that in S2 of Example IX, the hollow nano Ru-Ni catalyst used is from Preparation Example 1 and the mass is 21 g.

[0064] Example X

[0065] The difference between Example X and Example I is that in S2 of Example X, the hollow nano Ru-Ni catalyst used is from Preparation Example 1 and the mass is 3 g.

[0066] Example XI

[0067] Example XI is different from Example I in that the hollow nano Ru-Ni catalyst used in S2 of Example XI is from Preparation Example I and has a mass of 24 g.

[0068] Example XII

[0069] Example XII is different from Example I in that the hollow nano Ru-Ni catalyst used in S2 of Example XII is from Preparation Example II and has a mass of 6 g.

[0070] Example XIII

[0071] Example XIII is different from Example I in that the hollow nano Ru-Ni catalyst used in S2 of Example XIII is from Preparation Example III and has a mass of 6 g.

[0072] Comparative Example I

[0073] Comparative Example I is different from Example I in that the catalyst used in S2 in Comparative Example 1 is a Lindlar catalyst.

[0074] Performance detection test

[0075] The yields of the product ethyl trans-2-cis-4-decadienoate in Examples I-XIII and Comparative Example I were detected, and the results are shown in Table 1.

[0076] The specific detection results are as follows:

[0077] Table 1 Yield detection results

[0078] Yield / % Yield / % Example 1 82.1 Example 8 83.2 Example 2 81.4 Example 9 82.6 Example 3 82.7 Example 10 77.4 Example 4 83.5 Example 11 76.6 Example 5 81.8 Example 12 82.8 Example 6 78.5 Example 13 81.6 Example 7 78.9 Comparative Example 1 75.4

[0079] It can be seen from the detection results in Table 1 that this application can effectively improve the yield of ethyl trans-2-cis-4-decadienoate, and the yield can be increased to more than 81%.

[0080] It can be seen from the detection results of Examples I-III and Comparative Example I that the parameters for synthesizing ethyl trans-2-cis-4-decadienoate provided in this application are all beneficial to improving the yield of the product, and the hollow nano Ru-Ni catalyst provided in this application effectively improves the yield of the product compared with the traditional Lindlar catalyst.

[0081] It can be seen from the detection results of Examples I, IV, V, VI and VII that when the molar ratio of the basic catalyst, triethyl phosphonoacetate and 2-octanal used in preparing Intermediate 1 in this application is in the range of 0.5-1:0.5-2:1, the yield of the product can be effectively improved. If it is lower than or exceeds this range, the yield will decrease significantly.

[0082] As can be seen from the test results of Examples 1, 8, 9, 10 and 11, when the mass ratio of Intermediate 1 to the nanocatalyst used in the preparation of ethyl (E)-2-(Z)-4-decadienoate in this application is within the range of 1:0.2 - 0.7, the yield of the product can be effectively improved. If it is lower than or exceeds this range, the yield will decrease significantly.

[0083] As can be seen from the test results of Examples 1, 12 and 13, the parameters for preparing the hollow nano Ru-Ni catalyst provided in this application are all conducive to obtaining a catalyst that can improve the yield of the product.

[0084] The specific embodiments of this application are only explanations of this application, and they do not limit this application. After reading this specification, those skilled in the art can make modifications to the embodiments of this application that do not contribute creatively according to needs, but as long as they are within the scope of the claims of this application, they are protected by the patent law.

Claims

1. A method for synthesizing trans-2-cis-4-decadienoic acid ethyl ester, characterized in that: The following steps are involved: S1. The alkaline catalyst and solvent A are mixed and cooled, and then triethyl phosphonoacetate is added and stirred evenly, and 2-octanal is added, and refluxed at 70-80° C. for 20-26 hours. After the reaction is completed, the mixture is cooled to room temperature, and water is added for stirring and separation. After multiple extractions, the solvent is recovered and flash separated to obtain intermediate 1; S2. After the intermediate 1 is mixed with the nanocatalyst, solvent B is added, hydrogen is introduced under the protection of an inert gas, and a hydrogenation reaction is carried out at 30-40 ° C and 1-5 MPa hydrogen pressure. After the reaction is completed, the trans-2-cis-4-decadienoic acid ethyl ester is obtained by filtration and separation; The nano catalyst is a hollow nano Ru-Ni catalyst; The mass ratio of the intermediate 1 to the nanocatalyst is 1:0.2-0.7; The hollow nano Ru-Ni catalyst is composed of the following raw materials in parts by weight: 0.1-0.3 parts of nickel acetate tetrahydrate, 0.1-0.3 parts of ruthenium trichloride trihydrate, 24-30 parts of ethanol and 1-3 parts of hollow nano material; The alkaline catalyst is one of sodium hydride, sodium hydroxide, sodium amide or sodium ethoxide; The molar ratio of the alkaline catalyst, triethyl phosphonoacetate and 2-octanal is 0.5-1:0.5-2:1; The method for preparing the hollow nanomaterial comprises the following steps: Part of hexadecyltrimethylammonium is dissolved in a mixed solution of water and ethanol, ethylenediamine is added, and resorcinol is added. After stirring evenly, 37% formaldehyde by mass is added to the mixed solution, and stirred at room temperature for 2-3 hours to form spheres; then the remaining hexadecyltrimethylammonium and ethyl orthosilicate are added, and after stirring at room temperature for 4-6 hours, centrifugal separation, washing and drying are performed, and finally the obtained solid is transferred and calcined under argon protection to obtain a hollow nanomaterial.

2. A method for synthesizing trans-2-cis-4-decadienoic acid ethyl ester according to claim 1, characterized in that: The solvent A is one of ethanol, methanol, tetrahydrofuran or isopropanol.

3. A method for synthesizing trans-2-cis-4-decadienoic acid ethyl ester according to claim 1, characterized in that: The solvent B is one of cyclohexane, dimethyl ether or tetrahydrofuran.

4. A method for synthesizing trans-2-cis-4-decadienoic acid ethyl ester according to claim 1, characterized in that: The preparation method of the hollow nano Ru-Ni catalyst comprises the following steps: The hollow nanomaterial is ultrasonically dispersed in ethanol, and then nickel acetate tetrahydrate and ruthenium trichloride trihydrate are added, dispersed by ultrasonic treatment, and stirred at room temperature for 4-6 hours; then the ethanol is removed, and after drying at room temperature, the solid product is calcined in a hydrogen-containing mixed gas atmosphere to obtain a stable hollow nano Ru-Ni catalyst.

5. A method for synthesizing trans-2-cis-4-decadienoic acid ethyl ester according to claim 1, characterized in that: The hollow nano material is prepared from the following raw materials in parts by weight: 0.125-0.25 parts of hexadecyltrimethylammonium, 35-70 parts of water, 12-24 parts of ethanol, 0.15-0.28 parts of ethylenediamine, 0.16-0.3 parts of resorcinol, 0.24-0.48 parts of formaldehyde with a mass fraction of 37% and 0.6-1.2 parts of tetraethyl orthosilicate.