A device system and a method for preparing tetramethylheptanedione

Abstract

The application relates to a preparation device system and a preparation method of tetramethylheptanedione, wherein the preparation device system comprises a cleaning unit, a reaction unit, a distillation unit, a filtering unit and a vacuum distillation unit. The preparation method provided by the application is improved on the basis of a Claisen ester condensation reaction, the preparation method is matched with the preparation device, the occurrence of a side reaction can be effectively inhibited, then, through the operations of distillation, filtering and vacuum distillation on the reaction solution, 2,2,6,6-tetramethyl-3,5-heptanedione with high purity can be obtained, and the raw material conversion rate is high.

Description

Technical Field

[0001] This invention belongs to the field of chemical synthesis technology and relates to a method for synthesizing β-dicarbonyl compounds, specifically to a device system and method for preparing tetramethylheptanedione. Background Technology

[0002] 2,2,6,6-Tetramethyl-3,5-heptadecane is a β-dicarbonyl compound that can be used as an intermediate in organic synthesis. The dicarbonyl groups in 2,2,6,6-tetramethyl-3,5-heptadecane serve as coordination sites, facilitating the formation of structurally stable complexes with numerous metal ions. Furthermore, metal complexes of 2,2,6,6-tetramethyl-3,5-heptadecane have a wide range of applications. They can be used as catalysts in various synthetic reactions, exhibiting high catalytic performance. They can also form complexes with europium and praseodymium, serving as NMR shift reagents. More importantly, noble metal complexes of 2,2,6,6-tetramethyl-3,5-heptadecane can be used as precursors for MOCVD, and through further processing into semiconductor materials such as noble metal thin films, they show excellent application prospects.

[0003] 2,2,6,6-Tetramethyl-3,5-heptadecane is generally prepared via the Claisen ester condensation reaction, but due to the significant steric hindrance of 2,2,6,6-tetramethyl-3,5-heptadecane, its synthesis using this method is quite difficult. For example, existing technologies report the use of sodium amide as a catalyst to prepare 2,2,6,6-tetramethyl-3,5-heptadecane from methyl ketones and fatty esters, with a yield of approximately 20%. A synthesis of 2,2,6,6-tetramethyl-3,5-heptadecane using sodium hydride as a condensing agent, trimethylacetate and pinacolone as raw materials, and ethylene glycol dimethyl ether as a solvent, yields approximately 60%.

[0004] CN1636422A discloses a method for preparing β-diketone compounds and their metal complexes, comprising reacting alkyl neopentanoate with pinacolone in the presence of an alkali metal alkoxide catalyst without using other solvents and using alkyl neopentanoate as the solvent, or reacting them in an amide-type solvent or a urea-type solvent in the presence of an alkali metal alkoxide catalyst. The highest yield achieved by the disclosed preparation method is only 70%.

[0005] The low yield of 2,2,6,6-tetramethyl-3,5-heptadecane is due to reasons including, but not limited to: high water content in the feedstock, leading to catalyst denaturation and deactivation; excessively rapid addition of pinacolone or insufficient trimethylacetate, resulting in excessively high local concentrations of pinacolone and significant self-condensation of pinacolone. Furthermore, the post-processing of 2,2,6,6-tetramethyl-3,5-heptadecane via the Claisen condensation reaction involves acid neutralization, extraction, and vacuum distillation to obtain the product. This post-processing generates substantial waste liquid, and unreacted feedstock and catalyst are difficult to recover.

[0006] Therefore, it can be seen that the synthesis of 2,2,6,6-tetramethyl-3,5-heptadecane disclosed in the prior art has the disadvantages of low conversion rate, high preparation cost and complex post-processing, resulting in high preparation cost of 2,2,6,6-tetramethyl-3,5-heptadecane and making it difficult to achieve large-scale preparation and application. Summary of the Invention

[0007] In view of the shortcomings of the prior art, the purpose of this invention is to provide a device system and method for preparing tetramethylheptanedion, which can safely, stably, simply, cost-effectively and environmentally friendly prepare 2,2,6,6-tetramethyl-3,5-heptanedion.

[0008] To achieve this objective, the present invention adopts the following technical solution:

[0009] In a first aspect, the present invention provides a preparation apparatus system for tetramethylheptanedione, the preparation apparatus system comprising a cleaning unit, a reaction unit, a distillation unit, a filtration unit, and a vacuum distillation unit;

[0010] The reaction unit includes a reaction device and at least three independent raw material supply devices; the outlet of the raw material supply device is connected to the inlet of the reaction device.

[0011] The distillation unit includes a first condenser and an alcohol storage tank connected in sequence; the feed inlet of the first condenser is connected to the gas outlet of the reaction device.

[0012] The filtration unit includes a temporary storage tank and at least two sets of filtration devices connected in parallel; the inlet of the filtration device is connected to the outlet of the reaction device; the outlet of the filtration device is connected to the temporary storage tank.

[0013] The vacuum distillation unit includes a vacuum distillation apparatus, a condensation section, a cold trap, and a vacuum device connected in sequence; the condensation section includes a first condensation section and a second condensation section connected in parallel; the outlet of the temporary storage tank is connected to the inlet of the vacuum distillation apparatus.

[0014] The first condensation section includes a second condenser; the feed inlet of the second condenser is connected to the gas outlet of the vacuum distillation apparatus; the upper outlet of the second condenser is connected to a light phase storage tank; and the lower outlet of the second condenser is connected to a heavy phase storage tank.

[0015] The second condensation section includes a third condenser, and the lower outlet of the third condenser is connected to a product storage tank;

[0016] The cleaning unit includes protective gas purging pipelines that are connected to the raw material supply device.

[0017] The reaction apparatus in the preparation device system provided by this invention is further equipped with a stirring device. This invention does not impose excessive limitations on this device, as long as it can achieve the stirring function. The preparation device system provided by this invention also includes necessary connecting pipelines and valves. This invention does not impose excessive limitations on these, as long as they can fulfill the functions of each device.

[0018] The production apparatus provided by this invention can effectively suppress the occurrence of side reactions when applied to the preparation of 2,2,6,6-tetramethyl-3,5-heptadecane. With the operation of the distillation unit, filtration unit and vacuum distillation unit, 2,2,6,6-tetramethyl-3,5-heptadecane with high purity can be obtained and the raw material conversion rate is high.

[0019] Preferably, the reaction unit includes three independent raw material supply devices, namely a pinacolone supply device, a trimethylacetate supply device, and a catalyst dispersion supply device.

[0020] Preferably, the bottom outlet of the vacuum distillation apparatus is connected to a catalyst recovery storage tank.

[0021] Preferably, the discharge port of the heavy phase storage tank is connected to the reflux port of the vacuum distillation apparatus.

[0022] Preferably, the protective gas purging line is an inert gas purging line or a nitrogen purging line.

[0023] Preferably, the protective gas purging pipeline is also connected to a vacuum distillation apparatus for purging the solid catalyst in the vacuum distillation apparatus to a catalyst recovery storage tank.

[0024] In a second aspect, the present invention provides a method for preparing tetramethylheptanedione, the preparation method being carried out in the preparation apparatus system described in the first aspect, comprising the following steps:

[0025] (1) Trimethylacetate and catalyst dispersion are first mixed in the reaction apparatus, heated to the reaction temperature, and then pinacolone is added dropwise. After the addition is completed, the reaction continues until the end, and the reaction solution is obtained. During the reaction, the alcohol generated in the reaction is collected in the alcohol storage tank through the first condenser to promote the forward reaction.

[0026] (2) The reaction solution obtained in step (1) is distilled and the alcohol produced in the reaction is collected in an alcohol storage tank;

[0027] (3) The reaction solution after distillation in step (2) is filtered, and the undissolved catalyst is collected through the filtration device. The filtrate obtained from the filtration device is sent to the vacuum distillation device through a temporary storage tank. After vacuum distillation, 2,2,6,6-tetramethyl-3,5-heptadecane is obtained.

[0028] The preparation method provided by the present invention also includes protective gas replacement before the reaction, and the present invention does not impose too many limitations on this.

[0029] The preparation method provided by this invention is an improvement on the Claisen ester condensation reaction. The preparation method is carried out in conjunction with the preparation device, which can effectively suppress the occurrence of side reactions. Then, by distilling, filtering and vacuum distilling the reaction solution, 2,2,6,6-tetramethyl-3,5-heptadecane with high purity can be obtained and with high raw material conversion rate.

[0030] Preferably, the trimethyl acetate in step (1) comprises methyl trimethylacetate and / or ethyl trimethylacetate.

[0031] Preferably, the catalyst in the catalyst dispersion in step (1) includes any one or a combination of at least two of potassium tert-butoxide, sodium tert-butoxide, sodium hydride or sodium amino.

[0032] Preferably, the solvent in the catalyst dispersion in step (1) includes any one or a combination of at least two of N,N-dimethylformamide, ethylene glycol dimethyl ether, 1,4-dioxane or N-methyl-2-pyrrolidone.

[0033] Preferably, in the catalyst dispersion of step (1), the mass ratio of catalyst to solvent is 1:(2-10).

[0034] Preferably, the molar ratio of pinacolone to trimethylacetate in step (1) is 1:(1.2-3).

[0035] Preferably, the molar ratio of pinacolone to catalyst in step (1) is 1:(2-4).

[0036] Preferably, the reaction temperature in step (1) is in the range of 30-90℃;

[0037] Preferably, the dropwise addition time of pinacol in step (1) is 2-10 h.

[0038] Preferably, the reaction time in step (1) is 8-20 hours.

[0039] Preferably, the filtration in step (3) includes pressurized filtration protected by a protective gas.

[0040] Compared with the prior art, the present invention has the following beneficial effects:

[0041] (1) When the production apparatus provided by the present invention is applied to the preparation of 2,2,6,6-tetramethyl-3,5-heptadecane, it can effectively suppress the occurrence of side reactions. With the operation of the distillation unit, the filtration unit and the vacuum distillation unit, it can obtain 2,2,6,6-tetramethyl-3,5-heptadecane with high purity and high raw material conversion rate.

[0042] (2) The preparation method provided by the present invention is an improvement on the Claisen ester condensation reaction. The preparation method is carried out in conjunction with the preparation device, which can effectively suppress the occurrence of side reactions. Then, by distilling, filtering and vacuum distilling the reaction solution, 2,2,6,6-tetramethyl-3,5-heptadecane with high purity can be obtained and the raw material conversion rate is high. Attached Figure Description

[0043] Figure 1 This is a schematic diagram of the preparation apparatus system for tetramethylheptanedion provided in Embodiment 1 of the present invention;

[0044] Among them: 11, reaction apparatus; 12, pinacolone supply device; 13, trimethyl acetate supply device; 14, catalyst dispersion supply device; 21, first condenser; 22, alcohol storage tank; 31, first filtration device; 32, second filtration device; 33, temporary storage tank; 41, vacuum distillation device; 42, second condenser; 43, light phase storage tank; 44, heavy phase storage tank; 45, third condenser; 46, product storage tank; 47, cold trap; 48, vacuum device; 49, catalyst recovery storage tank. Detailed Implementation

[0045] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0046] An embodiment of the present invention provides a preparation apparatus system for tetramethylheptanedione, the preparation apparatus system comprising a cleaning unit, a reaction unit, a distillation unit, a filtration unit, and a vacuum distillation unit;

[0047] The reaction unit includes a reaction device and at least three independent raw material supply devices; the outlet of the raw material supply device is connected to the inlet of the reaction device.

[0048] The distillation unit includes a first condenser and an alcohol storage tank connected in sequence; the feed inlet of the first condenser is connected to the gas outlet of the reaction device.

[0049] The filtration unit includes a temporary storage tank and at least two sets of filtration devices connected in parallel; the inlet of the filtration device is connected to the outlet of the reaction device; the outlet of the filtration device is connected to the temporary storage tank.

[0050] The vacuum distillation unit includes a vacuum distillation apparatus, a condensation section, a cold trap, and a vacuum device connected in sequence; the condensation section includes a first condensation section and a second condensation section connected in parallel; the outlet of the temporary storage tank is connected to the inlet of the vacuum distillation apparatus.

[0051] The first condensation section includes a second condenser; the feed inlet of the second condenser is connected to the gas outlet of the vacuum distillation apparatus; the upper outlet of the second condenser is connected to a light phase storage tank; and the lower outlet of the second condenser is connected to a heavy phase storage tank.

[0052] The second condensation section includes a third condenser, and the lower outlet of the third condenser is connected to a product storage tank;

[0053] The cleaning unit includes protective gas purging pipelines that are connected to the raw material supply device.

[0054] The reaction apparatus in the preparation device system provided by this invention is further equipped with a stirring device. This invention does not impose excessive limitations on this device, as long as it can achieve the stirring function. The preparation device system provided by this invention also includes necessary connecting pipelines and valves. This invention does not impose excessive limitations on these, as long as they can fulfill the functions of each device.

[0055] The production apparatus provided by this invention can effectively suppress the occurrence of side reactions when applied to the preparation of 2,2,6,6-tetramethyl-3,5-heptadecane. With the operation of the distillation unit, filtration unit and vacuum distillation unit, 2,2,6,6-tetramethyl-3,5-heptadecane with high purity can be obtained and the raw material conversion rate is high.

[0056] This invention utilizes the boiling point differences between substances to set up a vacuum distillation unit, collecting the raw materials, solvent, and product separately. When the solvent's boiling point is lower than the product's, and if the solvent's boiling point is lower than the raw material's (e.g., ethylene glycol dimethyl ether or 1,4-dioxane), the solvent is collected in a light phase tank, and the raw material is collected in a heavy phase tank. If the solvent's boiling point is higher than the raw material's (e.g., N,N-dimethylformamide), the raw material is collected in a light phase tank, and the solvent is collected in a heavy phase tank. After removing the raw materials and solvent, the product is collected in a product storage tank via a third condenser.

[0057] When the solvent boiling point is higher than that of the product, for example, when the solvent is N-methyl-2-pyrrolidone, the raw material is collected in a light phase storage tank, the product is collected in a heavy phase storage tank, and the solvent and catalyst are retained in a vacuum distillation unit. After the catalyst content is detected, they are recycled.

[0058] For example, gas chromatography is used to analyze and detect the recovered materials in the storage tank of the recovered raw materials to obtain the proportions of trimethylacetate and catalyst, and then the mixture is reintroduced into the reaction device, and trimethylacetate and / or catalyst are added according to the process formula, and the reaction is carried out again.

[0059] In some embodiments, the reaction unit includes three independent raw material supply devices: a pinacolone supply device, a trimethylacetate supply device, and a catalyst dispersion supply device.

[0060] In some embodiments, the bottom outlet of the vacuum distillation apparatus is connected to a catalyst recovery storage tank.

[0061] In some embodiments, the discharge port of the heavy phase storage tank is connected to the reflux port of the vacuum distillation apparatus.

[0062] In some embodiments, the protective gas purging line is an inert gas purging line or a nitrogen purging line.

[0063] In some embodiments, the protective gas purging line is also connected to a vacuum distillation apparatus for purging the solid catalyst in the vacuum distillation apparatus to a catalyst recovery storage tank.

[0064] Some embodiments of the present invention provide a method for preparing tetramethylheptanedione, the preparation method being carried out in the preparation apparatus system provided in some embodiments, and including the following steps:

[0065] (1) Trimethylacetate and catalyst dispersion are first mixed in the reaction apparatus, heated to the reaction temperature, and then pinacolone is added dropwise. After the addition is completed, the reaction continues until the end, and the reaction solution is obtained. During the reaction, the alcohol generated in the reaction is collected in the alcohol storage tank through the first condenser to promote the forward reaction.

[0066] (2) The reaction solution obtained in step (1) is distilled and the alcohol produced in the reaction is collected in an alcohol storage tank;

[0067] (3) The reaction solution after distillation in step (2) is filtered, and the undissolved catalyst is collected through the filtration device. The filtrate obtained from the filtration device is sent to the vacuum distillation device through a temporary storage tank. After vacuum distillation, 2,2,6,6-tetramethyl-3,5-heptadecane is obtained.

[0068] The preparation method provided by the present invention also includes protective gas replacement before the reaction, and the present invention does not impose too many limitations on this.

[0069] The preparation method provided by this invention is an improvement on the Claisen ester condensation reaction. The preparation method is carried out in conjunction with the preparation device, which can effectively suppress the occurrence of side reactions. Then, by distilling, filtering and vacuum distilling the reaction solution, 2,2,6,6-tetramethyl-3,5-heptadecane with high purity can be obtained and with high raw material conversion rate.

[0070] In some embodiments, the trimethylacetate in step (1) comprises methyl trimethylacetate and / or ethyl trimethylacetate.

[0071] In some embodiments, the catalyst in the catalyst dispersion of step (1) includes any one or a combination of at least two of potassium tert-butoxide, sodium tert-butoxide, sodium hydride or sodium amino. Typical but non-limiting combinations include combinations of potassium tert-butoxide and sodium tert-butoxide, combinations of sodium hydride and sodium amino, combinations of potassium tert-butoxide, sodium tert-butoxide and sodium hydride, combinations of sodium tert-butoxide, sodium hydride and sodium amino, or combinations of potassium tert-butoxide, sodium tert-butoxide, sodium hydride and sodium amino.

[0072] In some embodiments, the solvent in the catalyst dispersion of step (1) includes any one or a combination of at least two of N,N-dimethylformamide, ethylene glycol dimethyl ether, 1,4-dioxane, or N-methyl-2-pyrrolidone. Typical but non-limiting combinations include combinations of N,N-dimethylformamide and ethylene glycol dimethyl ether, combinations of 1,4-dioxane and N-methyl-2-pyrrolidone, combinations of N,N-dimethylformamide, ethylene glycol dimethyl ether, and 1,4-dioxane, combinations of ethylene glycol dimethyl ether, 1,4-dioxane, and N-methyl-2-pyrrolidone, or combinations of N,N-dimethylformamide, ethylene glycol dimethyl ether, 1,4-dioxane, and N-methyl-2-pyrrolidone.

[0073] In some embodiments, the mass ratio of catalyst to solvent in the catalyst dispersion of step (1) is 1:(2-10), for example, it can be 1:2, 1:3, 1:5, 1:6, 1:8 or 1:10, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0074] In some embodiments, the molar ratio of pinacolone to trimethylacetate in step (1) is 1:(1.2-3), for example, it can be 1:1.2, 1:1.5, 1:2, 1:2.5 or 1:3, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable, preferably 1:1.5.

[0075] In some embodiments, the molar ratio of pinacolone to catalyst in step (1) is 1:(2-4), for example, it can be 1:2, 1:2.5, 1:3, 1:3.5 or 1:4, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable, preferably 1:3.

[0076] In some embodiments, the numerical range of the reaction temperature in step (1) is 30-90°C, for example, it can be 30°C, 40°C, 50°C, 60°C, 70°C, 80°C or 90°C, but is not limited to the listed values. Other unlisted values ​​within the numerical range are also applicable.

[0077] In some embodiments, the drop time of pinacol in step (1) is 2-10h, for example, it can be 2h, 3h, 4h, 5h, 6h, 7h, 8h, 9h or 10h, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0078] In some embodiments, the duration of the continued reaction in step (1) is 8-20 hours, for example, 8 hours, 10 hours, 12 hours, 15 hours, 16 hours, 18 hours or 20 hours, but not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0079] In some embodiments, the filtration in step (3) includes pressurized filtration protected by a protective gas.

[0080] Example 1

[0081] This embodiment provides a method such as Figure 1 The apparatus system for preparing tetramethylheptanedion shown includes a cleaning unit, a reaction unit, a distillation unit, a filtration unit, and a vacuum distillation unit.

[0082] The reaction unit includes a reaction device 11 and three independent raw material supply devices; the outlet of the raw material supply device is connected to the inlet of the reaction device 11; a stirring device is installed inside the reaction device 11.

[0083] Three independent raw material supply devices are provided: pinacolone supply device 12, trimethyl acetate supply device 13, and catalyst dispersion supply device 14.

[0084] The distillation unit includes a first condenser 21 and an alcohol storage tank 22 connected in sequence; the feed inlet of the first condenser 21 is connected to the gas outlet of the reaction device 11.

[0085] The filtration unit includes a temporary storage tank 33 and a first filtration device 31 and a second filtration device 32 connected in parallel; the inlets of the first filtration device 31 and the second filtration device 32 are independently connected to the outlet of the reaction device 11; the outlets of the first filtration device 31 and the second filtration device 32 are independently connected to the temporary storage tank 33.

[0086] The vacuum distillation unit includes a vacuum distillation apparatus 41, a condensation section, a cold trap 47, a vacuum device 48, and a catalyst recovery storage tank 49 connected in sequence; the condensation section includes a first condensation section and a second condensation section connected in parallel; the outlet of the temporary storage tank 33 is connected to the inlet of the vacuum distillation apparatus 41.

[0087] The first condensing section includes a second condenser 42; the inlet of the second condenser 42 is connected to the outlet of the vacuum distillation apparatus 41; the upper outlet of the second condenser 42 is connected to a light phase storage tank 43; the lower outlet of the second condenser 42 is connected to a heavy phase storage tank 44; the second condensing section includes a third condenser 45, and the lower outlet of the third condenser 45 is connected to a product storage tank 46.

[0088] The discharge port of the heavy phase storage tank 44 is connected to the reflux port of the vacuum distillation apparatus 41;

[0089] The lower outlet of the vacuum distillation apparatus 41 is connected to the catalyst recovery storage tank 49;

[0090] The cleaning unit includes protective gas purging pipelines connected to the raw material supply device, and the protective gas purging pipelines are nitrogen purging pipelines; the protective gas purging pipelines are also connected to the vacuum distillation device 41, and are used to purge the solid catalyst in the vacuum distillation device 41 to the catalyst recovery storage tank 49.

[0091] Application Example 1

[0092] This application example provides a method for preparing tetramethylheptanedione in the preparation apparatus system provided in Example 1, the preparation method comprising the following steps:

[0093] (1) The nitrogen purging pipeline provides a complete set of nitrogen purging equipment system. In the reaction device, trimethyl ethyl acetate and catalyst dispersion are first mixed, and the temperature is raised to the reaction temperature of 50°C. Then, pinacolone is added dropwise. After the addition is completed, the reaction continues for 12 hours to obtain the reaction solution. During the reaction, the alcohol generated in the reaction is collected in the alcohol storage tank through the first condenser.

[0094] The catalyst in the catalyst dispersion is potassium tert-butoxide, and the solvent is N,N-dimethylformamide, with a catalyst-to-solvent mass ratio of 1:5.

[0095] The molar ratio of pinacolone to ethyl trimethylacetate is 1:1.5, and the molar ratio of pinacolone to potassium tert-butoxide is 1:3.

[0096] The dropping rate of pinacolone was constant, and the dropping time was 4 hours.

[0097] (2) The reaction solution obtained in step (1) is distilled and the alcohol produced in the reaction is collected in an alcohol storage tank;

[0098] (3) The reaction liquid after distillation in step (2) is subjected to pressure filtration, and the undissolved catalyst is collected through the filtration device. The filtrate obtained by the filtration device enters the vacuum distillation device through a temporary storage tank. After vacuum distillation, the raw material is collected in the light phase storage tank, the solvent is collected in the heavy phase storage tank, and 2,2,6,6-tetramethyl-3,5-heptadecane is obtained in the product storage tank.

[0099] Application Example 2

[0100] This application example provides a method for preparing tetramethylheptanedione in the preparation apparatus system provided in Example 1, the preparation method comprising the following steps:

[0101] (1) The nitrogen purging pipeline provides a complete nitrogen purging system. In the reaction device, trimethyl ethyl acetate and catalyst dispersion are first mixed and heated to the reaction temperature of 30°C. Then, pinacolone is added dropwise. After the addition is completed, the reaction continues for 20 hours to obtain the reaction solution. During the reaction, the alcohol generated in the reaction is collected in the alcohol storage tank through the first condenser.

[0102] The catalyst in the catalyst dispersion is potassium tert-butoxide, and the solvent is N,N-dimethylformamide. The mass ratio of catalyst to solvent is 1:10.

[0103] The molar ratio of pinacolone to ethyl trimethylacetate is 1:3, and the molar ratio of pinacolone to potassium tert-butoxide is 1:4.

[0104] The dropping rate of pinacolone was constant, and the dropping time was 10 hours.

[0105] (2) The reaction solution obtained in step (1) is distilled and the alcohol produced in the reaction is collected in an alcohol storage tank;

[0106] (3) The reaction liquid after distillation in step (2) is subjected to pressure filtration, and the undissolved catalyst is collected through the filtration device. The filtrate obtained by the filtration device enters the vacuum distillation device through a temporary storage tank. After vacuum distillation, the raw material is collected in the light phase storage tank, the solvent is collected in the heavy phase storage tank, and 2,2,6,6-tetramethyl-3,5-heptadecane is obtained in the product storage tank.

[0107] Application Example 3

[0108] This application example provides a method for preparing tetramethylheptanedione in the preparation apparatus system provided in Example 1, the preparation method comprising the following steps:

[0109] (1) The nitrogen purging pipeline provides a complete nitrogen purging system. In the reaction device, trimethyl ethyl acetate and catalyst dispersion are first mixed and heated to the reaction temperature of 90°C. Then, pinacolone is added dropwise. After the addition is completed, the reaction continues for 8 hours to obtain the reaction solution. During the reaction, the alcohol generated in the reaction is collected in the alcohol storage tank through the first condenser.

[0110] The catalyst in the catalyst dispersion is potassium tert-butoxide, and the solvent is N,N-dimethylformamide. The mass ratio of catalyst to solvent is 1:2.

[0111] The molar ratio of pinacolone to ethyl trimethylacetate is 1:1.2, and the molar ratio of pinacolone to potassium tert-butoxide is 1:2.

[0112] The dropping rate of pinacolone was constant, and the dropping time was 2 hours.

[0113] (2) The reaction solution obtained in step (1) is distilled and the alcohol produced in the reaction is collected in an alcohol storage tank;

[0114] (3) The reaction liquid after distillation in step (2) is subjected to pressure filtration, and the undissolved catalyst is collected through the filtration device. The filtrate obtained by the filtration device enters the vacuum distillation device through a temporary storage tank. After vacuum distillation, the raw material is collected in the light phase storage tank, the solvent is collected in the heavy phase storage tank, and 2,2,6,6-tetramethyl-3,5-heptadecane is obtained in the product storage tank.

[0115] Application Example 4

[0116] This application example provides a method for preparing tetramethylheptanedione, which is the same as in Example 1 except that the solvent is replaced by an equal volume of ethylene glycol dimethyl ether.

[0117] In this application example, ethylene glycol dimethyl ether is collected in the light phase tank, unreacted raw materials are collected in the heavy phase tank, and 2,2,6,6-tetramethyl-3,5-heptadecane is obtained in the product tank.

[0118] Application Example 5

[0119] This application example provides a method for preparing tetramethylheptanedione, which is the same as in Example 1 except that the solvent is replaced by an equal volume of N-methyl-2-pyrrolidone.

[0120] In this application example, the raw material is collected in the light phase storage tank, and 2,2,6,6-tetramethyl-3,5-heptadecane is collected in the heavy phase storage tank.

[0121] Application Example 6

[0122] This application example provides a method for preparing tetramethylheptanedione, which is the same as in Example 1 except that the solvent is replaced by an equal volume of 1,4-dioxane.

[0123] Application Example 7

[0124] This application example provides a method for preparing tetramethylheptanedione, which is the same as in Example 1 except that the reaction temperature is adjusted to 55°C.

[0125] Application Example 8

[0126] This application example provides a method for preparing tetramethylheptanedione, which is the same as in Example 1 except that the catalyst is replaced with sodium hydride in an equimolar amount.

[0127] The product obtained in the above application example was weighed, and the yield of 2,2,6,6-tetramethyl-3,5-heptadecane was calculated based on pinacolone. The purity of the obtained 2,2,6,6-tetramethyl-3,5-heptadecane was detected by gas chromatography. The results are shown in Table 1.

[0128] Table 1

[0129]

[0130]

[0131] In summary, the production apparatus provided by this invention, when applied to the preparation of 2,2,6,6-tetramethyl-3,5-heptadecane, can effectively suppress the occurrence of side reactions. Combined with the operation of the distillation unit, filtration unit, and vacuum distillation unit, it can obtain 2,2,6,6-tetramethyl-3,5-heptadecane with high purity and a high raw material conversion rate. The preparation method provided by this invention is an improvement on the Claisen ester condensation reaction. The preparation method, combined with the preparation apparatus, can effectively suppress the occurrence of side reactions. Then, through distillation, filtration, and vacuum distillation of the reaction solution, it can obtain 2,2,6,6-tetramethyl-3,5-heptadecane with high purity and a high raw material conversion rate.

[0132] The above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A system for preparing tetramethylheptanedione, characterized in that, The preparation apparatus system includes a cleaning unit, a reaction unit, a distillation unit, a filtration unit, and a vacuum distillation unit; The reaction unit includes a reaction device and at least three independent raw material supply devices; the outlet of the raw material supply device is connected to the inlet of the reaction device. The distillation unit includes a first condenser and an alcohol storage tank connected in sequence; the feed inlet of the first condenser is connected to the gas outlet of the reaction device. The filtration unit includes a temporary storage tank and at least two sets of filtration devices connected in parallel; the inlet of the filtration device is connected to the outlet of the reaction device; the outlet of the filtration device is connected to the temporary storage tank. The vacuum distillation unit includes a vacuum distillation apparatus, a condensation section, a cold trap, and a vacuum device connected in sequence; the condensation section includes a first condensation section and a second condensation section connected in parallel; the outlet of the temporary storage tank is connected to the inlet of the vacuum distillation apparatus. The first condensation section includes a second condenser; the feed inlet of the second condenser is connected to the gas outlet of the vacuum distillation apparatus; the upper outlet of the second condenser is connected to a light phase storage tank; and the lower outlet of the second condenser is connected to a heavy phase storage tank. The second condensation section includes a third condenser, and the lower outlet of the third condenser is connected to a product storage tank; The cleaning unit includes protective gas purging pipelines that are connected to the raw material supply device.

2. The preparation apparatus system according to claim 1, characterized in that, The reaction unit includes three independent raw material supply devices: a pinacolone supply device, a trimethylacetate supply device, and a catalyst dispersion supply device.

3. The preparation apparatus system according to claim 1, characterized in that, The bottom outlet of the vacuum distillation apparatus is connected to the catalyst recovery storage tank.

4. The preparation apparatus system according to claim 1, characterized in that, The discharge port of the heavy phase storage tank is connected to the reflux port of the vacuum distillation unit.

5. The preparation apparatus system according to claim 3, characterized in that, The protective gas purging line is an inert gas purging line or a nitrogen purging line.

6. The preparation apparatus system according to claim 3, characterized in that, The protective gas purging pipeline is also connected to the vacuum distillation unit, and is used to purge the solid catalyst in the vacuum distillation unit to the catalyst recovery storage tank.

7. A method for preparing tetramethylheptanedione, characterized in that, The preparation method is carried out in the preparation apparatus system according to any one of claims 1-6, and includes the following steps: (1) Trimethylacetate and catalyst dispersion are first mixed in the reaction apparatus, heated to the reaction temperature, and then pinacolone is added dropwise. After the addition is completed, the reaction continues until the end, and the reaction solution is obtained. During the reaction, the alcohol generated in the reaction is collected in the alcohol storage tank through the first condenser to promote the forward reaction. (2) The reaction solution obtained in distillation step (1) is used to collect the alcohol produced in the reaction in an alcohol storage tank; (3) The reaction liquid after distillation in step (2) is filtered, and the undissolved catalyst is collected through the filtration device. The filtrate obtained by the filtration device is sent to the vacuum distillation device through a temporary storage tank. After vacuum distillation, 2,2,6,6-tetramethyl-3,5-heptadecane is obtained.

8. The preparation method according to claim 7, characterized in that, The trimethyl acetate in step (1) includes methyl trimethylacetate and / or ethyl trimethylacetate.

9. The preparation method according to claim 7, characterized in that, The catalyst in the catalyst dispersion in step (1) includes any one or a combination of at least two of potassium tert-butoxide, sodium tert-butoxide, sodium hydride or sodium amino.

10. The preparation method according to claim 7, characterized in that, The solvent in the catalyst dispersion in step (1) includes any one or a combination of at least two of N,N-dimethylformamide, ethylene glycol dimethyl ether, 1,4-dioxane or N-methyl-2-pyrrolidone.

11. The preparation method according to claim 7, characterized in that, In step (1), the mass ratio of catalyst to solvent in the catalyst dispersion is 1:(2-10).

12. The preparation method according to claim 7, characterized in that, The molar ratio of pinacolone to trimethylacetate in step (1) is 1:(1.2-3).

13. The preparation method according to claim 9, characterized in that, In step (1), the molar ratio of pinacolone to catalyst is 1:(2-4).

14. The preparation method according to claim 7, characterized in that, The reaction temperature in step (1) is in the range of 30-90℃.

15. The preparation method according to claim 7, characterized in that, The dropwise addition time of pinacol in step (1) is 2-10 h.

16. The preparation method according to claim 7, characterized in that, The reaction time described in step (1) is 8-20 hours.

17. The preparation method according to claim 7, characterized in that, The filtration in step (3) includes pressurized filtration with protective gas protection.

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