Separator and device and method for purifying 2-methyl-6-propionyl naphthalene

Abstract

The invention belongs to the technical field of separation and purification, and particularly relates to a separator and a device and method for purifying 2-methyl-6-propionyl naphthalene. The separator provided by the invention comprises an inner cylinder and an outer cylinder, the inner cylinder is arranged in the outer cylinder, the inner cylinder is provided with a feed pipe and a discharge pipe, the feed pipe and the discharge pipe respectively penetrate through the outer cylinder, the outer cylinder is provided with a discharge port, and the inner cylinder is made of at least one of polytetrafluoroethylene, polysiloxane, thermoplastic elastomer and polyurethane.

Description

Technical Field

[0001] The invention belongs to the technical field of separation and purification, and in particular relates to a separator and a device and a method for purifying 2-methyl-6-propionylnaphthalene. Background Art

[0002] 2,6-naphthalene dicarboxylic acid dimethyl ester (NDC) is a key intermediate for some high-end specialty polyesters, and its main use is to synthesize polyethylene 2,6-naphthalate (PEN). PEN is an emerging functional polymer resin material with superior performance. It is mainly obtained by esterification of 2,6-naphthalene dicarboxylic acid (2,6-NDA) and then high-temperature and high-vacuum polycondensation. Compared with the widely used polyethylene terephthalate (PET) and polybutylene terephthalate (PBT), this polymer material has better air tightness, mechanical properties, heat resistance, dyeing properties, resilience, anti-fouling properties and chemical stability. Therefore, PEN polyester materials are widely used in fiber textile materials, film materials, packaging materials, engineering plastics and other fields.

[0003] 2-Methylnaphthalene is subjected to acylation reaction to prepare 2-methyl-6-propionylnaphthalene, which is an important raw material for the preparation of 2,6-naphthalenedicarboxylic acid. Crude 2-methyl-6-propionylnaphthalene also contains a variety of isomers such as 2-methyl-7-propionylnaphthalene, with boiling points ranging from a few degrees Celsius to tens of degrees Celsius. The efficiency of the distillation method is low; the yield of the molecular distillation method is low; the heavy components are difficult to completely remove and the yield is low when the recrystallization method is used. How to efficiently and economically separate isomers is the key to improving the purity of 2-methyl-6-propionylnaphthalene and its industrial utilization. Summary of the invention

[0004] The present invention is based on the inventor's discovery and understanding of the following facts and problems:

[0005] CN113292409A discloses a method for separating 2-methyl-6-acylnaphthalene and 2-methyl-7-acylnaphthalene, which uses a purification method combining vacuum distillation, recrystallization and melt crystallization to separate 2-methyl-6-acylnaphthalene and its isomers, thereby improving the yield of 2-methyl-6-acylnaphthalene. "Synthesis and Molecular Structure Analysis of 2-Methyl-6-Acetylnaphthalene", Xu Jingwen, Clean Coal Technology, 2023, 29 (1): 39-47: Disclosed is a method for purifying 2-methyl-6-acylnaphthalene by distillation and recrystallization, with a purity greater than 98%. However, the existing method has a low yield and cumbersome procedures, which is not suitable for promotion and application in industrial production.

[0006] The present invention aims to solve one of the technical problems in the related art at least to a certain extent. To this end, an embodiment of the present invention provides a separator, which is used to purify 2-methyl-6-propionylnaphthalene, and the process of purifying 2-methyl-6-propionylnaphthalene can be shortened, and the obtained 2-methyl-6-propionylnaphthalene has a higher purity.

[0007] The separator provided in an embodiment of the present invention comprises an inner cylinder and an outer cylinder, wherein the inner cylinder is arranged in the outer cylinder, and the inner cylinder is provided with a feed pipe and a discharge pipe, wherein the feed pipe and the discharge pipe are respectively passed through the outer cylinder, and the outer cylinder is provided with a discharge port, and the material of the inner cylinder comprises at least one of polytetrafluoroethylene, polysiloxane, thermoplastic elastomer, and polyurethane.

[0008] The advantages and technical effects brought by the separator provided by the embodiment of the present invention are as follows: in the separator of the embodiment of the present invention, the material of the inner cylinder is made of at least one of polytetrafluoroethylene, polysiloxane, thermoplastic elastomer, and polyurethane, so that 2-methyl-6-propionylnaphthalene in the crude product can be separated, and the obtained 2-methyl-6-propionylnaphthalene has a higher purity.

[0009] In some embodiments, the outer cylinder is further provided with an air suction port, and the air suction port is located above the discharge port; and / or the outer cylinder is made of metal.

[0010] In some embodiments, the separator further comprises a scraper and a driving member, wherein the scraper is rotatably disposed in the outer cylinder, the scraper abuts against the outer wall surface of the inner cylinder, and the driving member is disposed at the top end of the outer cylinder, and the driving member is drivingly connected to the scraper.

[0011] The embodiment of the present invention further provides a device for purifying 2-methyl-6-propionylnaphthalene, comprising the above-mentioned separator.

[0012] The advantages and technical effects brought by the device for purifying 2-methyl-6-propionylnaphthalene in the embodiment of the present invention are that the device in the embodiment of the present invention is simple and easy to operate, can shorten the process of purifying 2-methyl-6-propionylnaphthalene, improve the processing efficiency, and the obtained 2-methyl-6-propionylnaphthalene has a higher purity.

[0013] In some embodiments, the device further comprises a raw material tank, a feed pump and a product collection tank, the outlet of the raw material tank is connected to the feed pipe of the separator through the feed pump, and the product collection tank is connected to the discharge port of the separator.

[0014] In some embodiments, the device further comprises a constant pressure valve, a vacuum pump and a heating device, wherein the constant pressure valve is arranged between the feed pump and the feed pipe of the separator, the vacuum pump is connected to the air extraction port of the separator, and the heating device is arranged on the periphery of the outer cylinder;

[0015] And / or, the device also includes a circulation system, which includes: a buffer tank, a circulation pump and a one-way valve, the outlet of the buffer tank is connected to the feed pipe of the separator through the circulation pump and the one-way valve in sequence, and the feed port of the buffer tank is connected to the outlet pipe of the separator.

[0016] An embodiment of the present invention also provides a method for purifying 2-methyl-6-propionylnaphthalene, comprising: injecting a crude 2-methyl-6-propionylnaphthalene raw material into a separator through a feed pipe of the separator, and collecting the 2-methyl-6-propionylnaphthalene through a discharge port of the separator after the 2-methyl-6-propionylnaphthalene precipitates on the outer wall surface of an inner cylinder of the separator.

[0017] In some embodiments, the method further includes: after 2-methyl-6-propionyl naphthalene is precipitated on the outer wall of the inner tube, starting the driving member of the separator to drive the scraper to rotate to scrape and collect the 2-methyl-6-propionyl naphthalene precipitated on the outer wall of the inner tube.

[0018] In some embodiments, the temperature in the separator is 60-140° C.; and / or the vacuum degree of the outer cylinder of the separator is 1000-5000 Pa, and the pressure of the inner cylinder of the separator is 1-2.5 MPa.

[0019] In some embodiments, the crude 2-methyl-6-propionylnaphthalene raw material includes nitrobenzene, 2-methyl-6-propionylnaphthalene and isomers thereof;

[0020] Preferably, the content of nitrobenzene in the crude 2-methyl-6-propionylnaphthalene raw material is 70-90wt%, and the content of 2-methyl-6-propionylnaphthalene and its isomers is 10-30wt%. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is a schematic diagram of the separator;

[0022] Figure 2 Schematic diagram of the device for purifying 2-methyl-6-propionylnaphthalene used in Example 1;

[0023] Figure 3 Schematic diagram of the device for purifying 2-methyl-6-propionylnaphthalene used in Example 2;

[0024] Figure 4 is a schematic diagram of the apparatus for purifying 2-methyl-6-propionylnaphthalene used in Example 4;

[0025] Figure numerals: 1-separator, 10-heating jacket, 11-inner cylinder, 12-outer cylinder, 13-scraper, 2-raw material tank, 3-feed pump, 4-product collecting tank, 5-regulating pressure valve, 6-vacuum pump, 7-buffer tank, 8-circulation pump, 9-check valve. DETAILED DESCRIPTION

[0026] Embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to be used to explain the present invention, but should not be understood as limiting the present invention.

[0027] like Figure 1 As shown, the separator 1 of the embodiment of the present invention comprises an inner cylinder 11 and an outer cylinder 12, the inner cylinder 11 is arranged in the outer cylinder 12, the inner cylinder 11 is provided with a feed pipe and a discharge pipe, the feed pipe and the discharge pipe are respectively passed through the outer cylinder 12, the outer cylinder 12 is provided with a discharge port, and the material of the inner cylinder 11 comprises at least one of polytetrafluoroethylene, polysiloxane, thermoplastic elastomer, and polyurethane.

[0028] In the separator 1 provided in the embodiment of the present invention, the inner cylinder 11 is made of at least one of polytetrafluoroethylene, polysiloxane, thermoplastic elastomer, and polyurethane, so that 2-methyl-6-propionylnaphthalene in the crude product can be separated, and the obtained 2-methyl-6-propionylnaphthalene has a higher purity.

[0029] In some embodiments, preferably, the thermoplastic elastomer includes at least one of styrene-based thermoplastic elastomer, polyolefin-based thermoplastic elastomer, and polyester-based thermoplastic elastomer.

[0030] In some embodiments, preferably, the outer cylinder 12 is further provided with an air extraction port, and the air extraction port is located above the discharge port; and / or, the outer cylinder 12 is made of metal. Further preferably, the outer cylinder 12 is made of 304 stainless steel or 316 stainless steel.

[0031] In some embodiments, preferably, the separator 1 also includes a scraper 13 and a driving member, wherein the scraper 13 is rotatably disposed in the outer cylinder 12, the scraper 13 abuts against the outer wall surface of the inner cylinder 11, and the driving member is disposed at the top end of the outer cylinder, and the driving member is transmission-connected to the scraper 13.

[0032] In the embodiment of the present invention, a rotatable scraper 13 is provided in the separator 1. After 2-methyl-6-propionylnaphthalene is precipitated on the outer wall surface of the inner cylinder 11, the driving member is turned on to drive the scraper 13 to rotate and scrape off the 2-methyl-6-propionylnaphthalene, which is beneficial to further improve the purification rate and yield of 2-methyl-6-propionylnaphthalene.

[0033] like Figure 2 As shown, an embodiment of the present invention further provides a device for purifying 2-methyl-6-propionylnaphthalene, comprising the above-mentioned separator 1.

[0034] The device for purifying 2-methyl-6-propionylnaphthalene according to the embodiment of the present invention is simple and easy to operate, can shorten the process of purifying 2-methyl-6-propionylnaphthalene, improve the processing efficiency, and the obtained 2-methyl-6-propionylnaphthalene has a higher purity.

[0035] like Figure 2 As shown, the device also includes a raw material tank 2, a feed pump 3 and a product collection tank 4. The outlet of the raw material tank 2 is connected to the feed pipe of the separator 1 through the feed pump 3, and the product collection tank 4 is connected to the discharge port of the separator 1.

[0036] like Figure 3 As shown, in some embodiments, preferably, the device further comprises a constant pressure valve 5, a vacuum pump 6 and a heating device, wherein the constant pressure valve 5 is arranged between the feed pump 3 and the feed pipe of the separator 1, the vacuum pump 6 is connected to the air extraction port of the separator 1, and the heating device is arranged on the periphery of the outer cylinder. Further preferably, the heating device is a heating sleeve 10.

[0037] and / or, if Figure 4 As shown, the device also includes a circulation system, which includes: a buffer tank 7, a circulation pump 8 and a one-way valve 9. The discharge port of the buffer tank 7 is connected to the feed pipe of the separator 1 through the circulation pump 8 and the one-way valve 9 in sequence, and the feed port of the buffer tank 7 is connected to the discharge pipe of the separator.

[0038] In the embodiment of the present invention, by adding a constant pressure valve 5 and a vacuum pump 6, the inner cylinder 11 of the separator 1 can be made positive pressure and the outer cylinder 12 can be made negative pressure, thereby improving the mass transfer efficiency of 2-methyl-6-propionyl naphthalene on the inner cylinder 11 and accelerating the separation of 2-methyl-6-propionyl naphthalene; by adding a heating device, the movement rate of 2-methyl-6-propionyl naphthalene is increased, and the separation and purification of 2-methyl-6-propionyl naphthalene is further accelerated. By adding a circulation system, the crude 2-methyl-6-propionyl naphthalene raw material can be circulated in the separator 1, and the yield of 2-methyl-6-propionyl naphthalene can be improved.

[0039] An embodiment of the present invention also provides a method for purifying 2-methyl-6-propionylnaphthalene, comprising: injecting a crude 2-methyl-6-propionylnaphthalene raw material into the separator 1 through the feed pipe of the separator 1, and collecting the 2-methyl-6-propionylnaphthalene through the discharge port of the separator 1 after precipitating on the outer wall surface of the inner cylinder 11 of the separator 1.

[0040] In some embodiments, preferably, the method further comprises: after 2-methyl-6-propionyl naphthalene is precipitated on the outer wall surface of the inner tube 11, starting the driving member of the separator 1 to drive the scraper 13 to rotate and scrape and collect the 2-methyl-6-propionyl naphthalene precipitated on the outer wall surface of the inner tube 11. Further preferably, the rotation speed of the scraper 13 is 10 to 50 rpm.

[0041] In some embodiments, preferably, the temperature in the separator 1 is 60-140°C; and / or, the vacuum degree of the outer cylinder 12 of the separator 1 is 1000-5000 Pa, and the pressure of the inner cylinder 11 of the separator 1 is 1-2.5 MPa. Further preferably, the temperature in the separator 1 is 100-120°C; and / or, the vacuum degree of the outer cylinder 12 of the separator 1 is 1000-2000 Pa, and the pressure of the inner cylinder 11 of the separator 1 is 2-2.5 MPa.

[0042] In the embodiment of the present invention, the temperature in the separator 1 is optimized, which is conducive to improving the mass transfer efficiency of 2-methyl-6-propionyl naphthalene on the inner cylinder 11 and improving the purification speed of 2-methyl-6-propionyl naphthalene. If the temperature is low, the mass transfer efficiency of 2-methyl-6-propionyl naphthalene on the inner cylinder 11 is low, and the purification time is long. If the temperature is high, the material of the inner cylinder 11 may age or soften, resulting in reduced separation purity. The vacuum degree of the outer cylinder 12 and the pressure of the inner cylinder 11 are optimized, and a pressure difference is formed between the inner cylinder 11 and the outer cylinder 12, which is conducive to further improving the mass transfer efficiency of 2-methyl-6-propionyl naphthalene on the inner cylinder 11 and further shortening the time required for purification. If the vacuum degree of the outer cylinder 12 or the pressure of the inner cylinder 11 is too high, the pressure of the inner cylinder 11 is too high, and the pressure bearing capacity of the material of the inner cylinder 11 is limited, and rupture may occur. If the vacuum degree of the outer cylinder 12 is too high, the energy consumption becomes large.

[0043] In some embodiments, preferably, the crude 2-methyl-6-propionylnaphthalene raw material comprises nitrobenzene, 2-methyl-6-propionylnaphthalene and isomers thereof. Further preferably, the content of nitrobenzene in the crude 2-methyl-6-propionylnaphthalene raw material is 70-90wt%, and the content of 2-methyl-6-propionylnaphthalene and isomers thereof is 10-30wt%.

[0044] In some embodiments, preferably, the crude 2-methyl-6-propionylnaphthalene raw material is circulated in the inner drum 11 of the separator 1 through a circulation system.

[0045] The technical solution of the present invention is described in detail below in conjunction with specific embodiments and drawings.

[0046] Example 1

[0047] use Figure 2The device shown is used to separate and process the crude 2-methyl-6-propionylnaphthalene raw material, and the specific steps are as follows:

[0048] (1) using a feed pump 3 to inject the crude 2-methyl-6-propionylnaphthalene raw material in the raw material tank 2 into the separator 1 through the feed pipe of the inner cylinder 11, the main material of the inner cylinder 11 is polytetrafluoroethylene, and the material of the outer cylinder 12 is 304 stainless steel;

[0049] (2) When 2-methyl-6-propionylnaphthalene is precipitated on the outer wall of the inner cylinder 11, the driving member is turned on to drive the scraper 13 to rotate. The speed of the scraper 13 is 30 rpm. After the 2-methyl-6-propionylnaphthalene is scraped off, it is transported to the product collection tank 4 through the discharge port of the outer cylinder 12.

[0050] Example 2

[0051] use Figure 3 The device shown is used to separate and process the crude 2-methyl-6-propionylnaphthalene raw material, and the specific steps are as follows:

[0052] (1) using a feed pump 3 to inject the crude 2-methyl-6-propionylnaphthalene raw material in the raw material tank 2 into the separator 1 through the feed pipe of the inner cylinder 11, the main material of the inner cylinder 11 is polytetrafluoroethylene, and the material of the outer cylinder 12 is 304 stainless steel;

[0053] (2) Open the constant pressure valve 5, vacuum pump 6 and heating jacket 10, increase the pressure of the inner cylinder 11 of the separator 1 to 2 MPa, evacuate the outer cylinder 12 of the separator 1 to 3000 Pa, and heat the temperature of the separator 1 to 100°C;

[0054] (3) When 2-methyl-6-propionylnaphthalene is precipitated on the outer wall of the inner cylinder 11, the driving member is turned on to drive the scraper 13 to rotate. The speed of the scraper 13 is 30 rpm. The separated 2-methyl-6-propionylnaphthalene is transported to the product collection tank 4 through the discharge port of the outer cylinder 12.

[0055] Example 3

[0056] use Figure 4 The device shown is used to separate and process the crude 2-methyl-6-propionylnaphthalene raw material, and the specific steps are as follows:

[0057] (1) using a feed pump 3 to inject the crude 2-methyl-6-propionylnaphthalene raw material in the raw material tank 2 into the separator 1 through the feed pipe of the inner cylinder 11, the main material of the inner cylinder 11 is polytetrafluoroethylene, and the material of the outer cylinder 12 is 316 stainless steel;

[0058] (2) opening the circulation pump 8 and the one-way valve 9, allowing the crude 2-methyl-6-propionylnaphthalene raw material to enter the buffer tank 7 from the discharge pipe of the inner cylinder 11, and then from the buffer tank 7, passing through the circulation pump 8 and the one-way valve 9 in sequence, and entering the separator 1 from the feed pipe of the inner cylinder 11 for circulation treatment;

[0059] (3) Open the constant pressure valve 5, vacuum pump 6 and heating jacket 10, increase the pressure of the inner cylinder 11 of the separator 1 to 2 MPa, evacuate the outer cylinder 12 of the separator 1 to 3000 Pa, and heat the temperature of the separator 1 to 100°C;

[0060] (4) The separated 2-methyl-6-propionylnaphthalene is transported to the product collection tank 4 through the discharge port of the outer cylinder 12.

[0061] Example 4

[0062] The method of this embodiment is the same as that of Embodiment 3, except that, in step (4): when 2-methyl-6-propionylnaphthalene is precipitated on the outer wall of the inner cylinder 11, the driving member is turned on to drive the scraper 13 to rotate, the speed of the scraper 13 is 30 rpm, and the separated 2-methyl-6-propionylnaphthalene is transported to the product collection tank 4 through the discharge port of the outer cylinder 12.

[0063] Example 5

[0064] The method of this embodiment is the same as that of Embodiment 4, except that in step (1), the material of the inner cylinder 11 is polysiloxane.

[0065] Example 6

[0066] The method of this embodiment is the same as that of Embodiment 4, except that in step (1), the material of the inner tube 11 is polyurethane.

[0067] Examples 7 to 21

[0068] The methods of Examples 7 to 21 are the same as those of Example 4, except that the process parameters are different. The specific process parameters are shown in Table 1.

[0069] Comparative Example 1

[0070] The method of this comparative example is the same as that of Example 3, except that in step (1), the material of the inner cylinder 11 is polyvinyl chloride (PVC).

[0071] Table 1

[0072]

[0073]

[0074] In the present invention, the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" etc. mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the described specific features, structures, materials or characteristics may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0075] Although the above embodiments have been shown and described, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations on the present invention. Changes, modifications, substitutions and variations of the above embodiments by those of ordinary skill in the art are all within the scope of protection of the present invention.

Claims

1. A separator, characterized in that: It includes an inner cylinder and an outer cylinder, the inner cylinder is arranged in the outer cylinder, the inner cylinder is provided with a feed pipe and a discharge pipe, the feed pipe and the discharge pipe are respectively passed through the outer cylinder, the outer cylinder is provided with a discharge port, and the material of the inner cylinder includes at least one of polytetrafluoroethylene, polysiloxane, thermoplastic elastomer, and polyurethane.

2. The separator according to claim 1, characterized in that The outer cylinder is also provided with an air suction port, and the air suction port is located above the discharge port; and / or the outer cylinder is made of metal.

3. The separator according to claim 1 or 2, characterized in that: The separator also includes a scraper and a driving member. The scraper is rotatably arranged in the outer cylinder and abuts against the outer wall surface of the inner cylinder. The driving member is arranged at the top of the outer cylinder and is drivingly connected to the scraper.

4. A device for purifying 2-methyl-6-propionylnaphthalene, characterized in that: A separator comprising the separator according to any one of claims 1 to 3.

5. The device for purifying 2-methyl-6-propionylnaphthalene according to claim 4, characterized in that: The device also includes a raw material tank, a feed pump and a product collection tank. The outlet of the raw material tank is connected to the feed pipe of the separator through the feed pump, and the product collection tank is connected to the discharge port of the separator.

6. The device for purifying 2-methyl-6-propionylnaphthalene according to claim 5, characterized in that: The device further comprises a constant pressure valve, a vacuum pump and a heating device, wherein the constant pressure valve is arranged between the feed pump and the feed pipe of the separator, the vacuum pump is connected to the air extraction port of the separator, and the heating device is arranged on the periphery of the outer cylinder; And / or, the device also includes a circulation system, which includes: a buffer tank, a circulation pump and a one-way valve, the outlet of the buffer tank is connected to the feed pipe of the separator through the circulation pump and the one-way valve in sequence, and the feed port of the buffer tank is connected to the outlet pipe of the separator.

7. A method for purifying 2-methyl-6-propionylnaphthalene using the device according to any one of claims 4 to 6, characterized in that: include: The crude 2-methyl-6-propionylnaphthalene raw material is injected into the separator through the feed pipe of the separator, and after the 2-methyl-6-propionylnaphthalene is precipitated on the outer wall surface of the inner cylinder of the separator, it is collected through the discharge port of the separator.

8. The method for purifying 2-methyl-6-propionylnaphthalene according to claim 7, characterized in that: The method further comprises: after 2-methyl-6-propionylnaphthalene is precipitated on the outer wall surface of the inner cylinder, starting the driving member of the separator to drive the scraper to rotate to scrape and collect the 2-methyl-6-propionylnaphthalene precipitated on the outer wall surface of the inner cylinder.

9. The method for purifying 2-methyl-6-propionylnaphthalene according to claim 7, characterized in that: The temperature in the separator is 60-140° C.; and / or the vacuum degree of the outer cylinder of the separator is 1000-5000 Pa, and the pressure of the inner cylinder of the separator is 1-2.5 MPa.

10. The method for purifying 2-methyl-6-propionylnaphthalene according to claim 7, characterized in that: The crude 2-methyl-6-propionylnaphthalene raw material includes nitrobenzene, 2-methyl-6-propionylnaphthalene and isomers thereof; Preferably, the content of nitrobenzene in the crude 2-methyl-6-propionylnaphthalene raw material is 70-90wt%, and the content of 2-methyl-6-propionylnaphthalene and its isomers is 10-30wt%.

Images