Device and method for purifying electronic-grade propylene glycol monomethyl ether

Abstract

The invention belongs to the technical field of purification and preparation devices of organic compounds, and discloses a device and a method for purifying electronic-grade propylene glycol monomethyl ether (PGME). The device comprises a cyclohexane feeding pump, a propylene glycol monomethyl ether feeding pump, a cyclohexane preheater, a propylene glycol monomethyl ether preheater, a first azeotropic rectifying tower, a second rectifying tower, a three-way valve, a resin column feeding pump, a first mixed resin column, a second resin column, an intermediate tank and a membrane separator. A tower kettle discharging opening of the azeotropic rectifying tower is connected with a feeding opening of the second rectifying tower through a pipeline; a tower top discharging opening of the second rectifying tower is connected to a feeding opening of the mixed resin column through a pipeline, a resin column feeding pump and a three-way valve. The device and the method provided by the invention are a green chemical device which is simple in process, energy-saving, efficient, stable in product quality, capable of realizing continuous production and high in economic benefit.

Description

Technical Field

[0001] The invention belongs to the technical field of purification and preparation devices for organic compounds, and particularly relates to a device and method for preparing electronic-grade propylene glycol monomethyl ether. Background Art

[0002] The molecular formula of propylene glycol monomethyl ether (PGME) is CH3CHOHCH2OCH3. The molecule contains two oxygen-containing functional groups, hydroxyl and ether bonds, which give it good solubility and can be easily dissolved in polar and non-polar substances. Therefore, it is often called a "universal" solvent in the industrial field. In the advanced process of integrated circuits, propylene glycol monomethyl ether (PGME) is usually used as a cleaning agent, stripping agent and diluent, and is an environmentally friendly and low-toxic substitute for ethylene glycol monomethyl ether. With the refinement and complexity of integrated circuits, higher requirements are placed on the purity of supporting electronic chemicals, especially the metal ion content in chemicals, which will seriously affect the life and stability of electronic components. Usually, the purification of organic reagents is completed by multi-tower distillation, but it is difficult to meet the requirements of electronic-grade high-purity reagents for the content of metal impurities. Ion exchange technology is one of the basic technologies for recovering strategic metals and promoting social development and progress.

[0003] At present, the method for industrial production of propylene glycol methyl ether is to use catalyst to catalyze propylene oxide and methanol to react to obtain, but a large amount of water and a by-product 2-methoxy-1-propanol with higher toxicity will be generated in the process. In addition, the catalyst used in many production processes will also introduce metal ion impurities. Liu Zhun et al. disclose a continuous production device for electronic grade propylene glycol methyl ether (Liu Zhun et al., Chinese patent CN202519180U, November 7, 2012), the device uses a solid base catalyst to react in a fixed bed to generate propylene glycol methyl ether, and then successively passes through a dealcoholization tower and a deionization tower to obtain electronic grade propylene glycol methyl ether, but the removal of by-products is not mentioned. Zhang Zaizhong et al. disclosed a device for preparing electronic-grade propylene glycol monomethyl ether (Zhang Zaizhong et al., Chinese patent CN211636466U, October 9, 2020), which uses an alkaline ionic liquid catalyst to generate a product in a microchannel reactor, followed by negative pressure distillation to remove excess reactants, and the resulting reaction solution is evaporated into steam through a thin film evaporator and then subjected to negative pressure distillation again, and electronic-grade propylene glycol monomethyl ether is obtained in the side line of the distillation tower, but there are multiple morphological transformations in the process, and the energy consumption is relatively high. Wang Jincheng et al. disclosed a method for preparing semiconductor-grade propylene glycol monomethyl ether (Wang Jincheng et al., Chinese patent CN113480414A, October 8, 2021), which is purified by a methanol distillation tower, a light removal tower, a heavy removal tower, a dehydration tower, an ion exchange resin and an ultrafilter, and the process energy consumption and cost are both relatively high.

[0004] In summary, the existing technology has problems such as high energy consumption, high cost and incomplete removal of by-products when producing propylene glycol methyl ether. There is an urgent need for a new and efficient purification method to meet the application requirements of electronic-grade propylene glycol methyl ether in integrated circuit manufacturing. Summary of the invention

[0005] The invention aims at the problems that the current method for purifying industrial-grade propylene glycol methyl ether does not consider the removal of by-products, has high energy consumption and complicated processes, and provides a green chemical technology with simple process, energy saving and high efficiency, stable product quality and continuous production.

[0006] The technical solution of the present invention is:

[0007] A purification device for electronic grade propylene glycol methyl ether, the purification device comprising a first azeotropic distillation tower, a second distillation tower, a three-way valve, a first mixed resin column, a second resin column, an intermediate tank and a membrane separator which are connected in sequence;

[0008] A cyclohexane feed port is arranged at the upper portion of the first azeotropic distillation tower, and the cyclohexane feed port is sequentially connected to a cyclohexane preheater and a cyclohexane feed pump through a feed pipeline;

[0009] A propylene glycol methyl ether feed port is arranged in the middle of the first azeotropic distillation tower, and the propylene glycol methyl ether feed port is connected to a propylene glycol methyl ether preheater and a propylene glycol methyl ether feed pump in sequence through a feed pipeline;

[0010] The bottom discharge port of the first azeotropic distillation tower is connected to the feed port of the second distillation tower through a pipeline; the top discharge port of the second distillation tower is connected to the feed port of the first mixed resin column through a resin column feed pump, a three-way valve and a connecting pipeline; the second resin column discharge port is connected to the membrane separator through a connecting pipeline and a feed pump.

[0011] The first azeotropic distillation tower, the second distillation tower, the first mixed resin column, the second resin column, the intermediate tank and the membrane separator are sequentially arranged in series; the cyclohexane feed pipeline is provided with a cyclohexane feed pump and a cyclohexane preheater; the industrial-grade propylene glycol methyl ether feed pipeline is provided with a propylene glycol methyl ether feed pump and a propylene glycol methyl ether preheater.

[0012] The azeotropic agent cyclohexane used in the azeotropic distillation tower is fed separately from the raw material, and the discharge port of the azeotropic distillation tower kettle is connected to the feed port of the second distillation tower through a pipeline; the discharge port at the top of the second distillation tower is connected to the feed port of the first mixed resin column through a feed pump, a three-way valve and a connecting pipeline; the discharge port of the second resin column is connected to the membrane separator through a connecting pipeline and a feed pump.

[0013] Furthermore, the three-way valve, the connecting pipeline between the two resin columns and the resin column are all made of PFA material or have a PFA inner coating.

[0014] Furthermore, the first mixed resin column and the second resin column each include two identical resin columns arranged in parallel, and a three-way valve is arranged on the connecting pipeline.

[0015] Furthermore, the filler in the first mixed resin column is composed of a uniform mixture of a styrene-based strongly acidic cation exchange resin and a styrene-based strongly basic anion exchange resin. The filler in the second resin column is composed of a macroporous resin.

[0016] Furthermore, the resins are all pretreated before use, the cation exchange resin is converted into a hydrogen type, the anion exchange resin is converted into a hydroxy type, and are washed with raw materials before use.

[0017] Furthermore, the separation membrane used in the membrane separator is a polytetrafluoroethylene membrane with a membrane pore diameter of 0.1 to 1 μm.

[0018] Furthermore, a reflux tank is provided on the pipeline between the top discharge port of the second distillation tower and the first mixed resin column.

[0019] The present invention also provides a purification method using the purification device of electronic-grade propylene glycol methyl ether PGME, comprising the following steps:

[0020] (1) Cyclohexane and industrial-grade propylene glycol methyl ether are fed into the upper and middle parts of the first azeotropic distillation tower, respectively. Cyclohexane is preheated to 20-40° C. in a preheater, and industrial-grade propylene glycol methyl ether is preheated to 30-50° C. in a preheater;

[0021] The first azeotropic distillation tower has 30 to 40 plates, an operating reflux ratio of 0.8 to 2, preferably in the range of 0.8 to 1.5, and a tower top pressure of 0.1 to 0.3 MPa. The tower top discharge is water and cyclohexane, the temperature is stabilized at 70°C to 80°C, and the tower bottom discharge is a crude product of propylene glycol methyl ether, including 2-methoxy-1-propanol, and the temperature is stabilized at 140°C to 150°C.

[0022] The mass flow rate ratio of the industrial-grade propylene glycol methyl ether to cyclohexane is 1:2 to 1:4.

[0023] In order to facilitate the recovery of cyclohexane and improve economic efficiency, a cyclohexane storage tank is connected to the tower top outlet pipeline, and the cyclohexane can be recycled as an azeotropic agent feed after subsequent separation from water.

[0024] (2) The crude product of propylene glycol methyl ether enters the second distillation tower to remove 2-methoxy-1-propanol.

[0025] The number of plates of the second distillation tower is 35 to 45, the top pressure is 10 KPa to 200 KPa, the ratio of the mass flow rate of the top distillate to the mass flow rate of the feed is 0.6:1 to 0.9:1, the top discharge is 99.99% propylene glycol methyl ether, the top temperature is stable at 50 to 60°C, the bottom discharge is 2-methoxy-1-propanol, and the bottom temperature is stable at 60 to 70°C.

[0026] In order to facilitate the collection of 2-methoxy-1-propanol, a 2-methoxy-1-propanol storage tank is connected to a discharge pipeline of the second distillation tower kettle.

[0027] In order to facilitate reflux, a reflux tank is provided to be connected to a pipeline of a discharge port at the top of the second distillation tower, and the reflux tank is connected to a three-way valve and the first mixed resin column through a pipeline.

[0028] (3) The top product of the second distillation tower enters the first mixed resin column through a feed pump. The filler in the column is a uniform mixture of strongly acidic cation exchange resin and strongly basic anion exchange resin, the mass ratio of the two is 0.8-1.5, the filler height-diameter ratio is 3-6, the feed flow rate is 10-20 BV / h, preferably, the resin particle size is 0.2-0.4, the uniformity coefficient is 1.3-1.5, and when the resin column adsorbs to a point close to the breakthrough point, it is switched to another identical resin column in parallel through a three-way valve.

[0029] The anion and cation exchange resins are both styrene-based resins.

[0030] The three-way valve, the connecting pipeline between the propylene glycol methyl ether storage tank and the first mixed resin column, and the first resin column are all made of PFA material.

[0031] (4) After the crude propylene glycol methyl ether passes through the first mixed resin column to remove most of the anions and most of the metal cations, it then enters the second resin column through a three-way valve to further remove ionic impurities. The filler in the second resin column is a macroporous resin with a height-to-diameter ratio of 3 to 6 and a flow rate of 10 to 20 BV / h. Preferably, the resin particle size is 0.4 to 0.6 and the resin uniformity coefficient is 1.0 to 1.2. When the resin column adsorbs to a point close to the breakthrough point, it is switched to another identical resin column in parallel through a three-way valve. The discharge product of the second resin column enters the middle tank.

[0032] The three-way valve, the connecting pipeline between the first mixed resin column and the second resin column, and the second resin column are all made of PFA material.

[0033] (5) The propylene glycol methyl ether in the middle tank enters the membrane separator to further remove tiny solid particles.

[0034] The separation membrane used in the membrane separator is a polytetrafluoroethylene membrane with a membrane pore diameter of 0.1 to 1 μm.

[0035] Compared with the prior art, the present invention has the following advantages:

[0036] The invention uses economical, low-toxic and highly efficient cyclohexane as an azeotropic agent, and can effectively remove a large amount of water in industrial-grade propylene glycol methyl ether. A second rectification tower is arranged to remove the byproduct 2-methoxy-1-propanol that may be contained in the industrial-grade propylene glycol methyl ether, and the purity of the propylene glycol methyl ether can be purified to 99.99%, and the byproduct can be recovered.

[0037] The present invention uses a variety of adsorption resins to remove metal ion impurities, which is green and energy-saving, and can purify most metal cation impurities to less than 0.1 ppb. The three-way valve allows the process flow to be replaced and regenerated in the middle of the resin column to achieve continuous production. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 A schematic diagram of a purification device for electronic-grade propylene glycol monomethyl ether provided by the present invention.

[0039] Among them, 1 is a cyclohexane feed pump; 2 is a propylene glycol methyl ether feed pump; 3 is a cyclohexane preheater; 4 is a propylene glycol methyl ether preheater; 5 is a first azeotropic distillation tower; 6 is a second distillation tower feed pump; 7 is a second distillation tower; 8 is a first mixed resin column feed pump; 9 and 10 are both first mixed resin columns; 11 and 12 are both second resin columns; 13 is a 2-methoxy-1-propanol storage tank; 14 is a cyclohexane storage tank; 15 is an intermediate tank; 16 is a membrane separator feed pump; 17 is a membrane separator. DETAILED DESCRIPTION

[0040] A schematic diagram of a purification device for electronic grade propylene glycol monomethyl ether is shown in FIG. Figure 1 shown.

[0041] The present invention provides a purification device for electronic grade propylene glycol methyl ether, comprising a cyclohexane feed pump 1, a propylene glycol methyl ether feed pump 2, a cyclohexane preheater 3, a propylene glycol methyl ether preheater 4, a first azeotropic distillation tower 5, a second distillation tower feed pump 6, a second distillation tower 7, a first mixed resin column feed pump 8, first mixed resin columns 9 and 10, second resin columns 11 and 12, a 2-methoxy-1-propanol storage tank 13, a cyclohexane storage tank 14, an intermediate tank 15, a membrane separator feed pump 16 and a membrane separator 17. A cyclohexane feed pipeline is provided with a cyclohexane feed pump and a cyclohexane preheater, and an industrial grade propylene glycol methyl ether feed pipeline is provided with a propylene glycol methyl ether feed pump and a propylene glycol methyl ether preheater. The top discharge port of the second distillation tower is connected to the feed port of the first mixed resin column through a first mixed resin column feed pump, a three-way valve and a connecting pipeline. The discharge port of the first mixed resin column is connected to the feed port of the second resin column through a three-way valve and a connecting pipeline. The discharge port of the second resin column is connected to the membrane separator through a connecting pipeline and a feed pump.

[0042] The purification method operation process is as follows:

[0043] (1) Cyclohexane and industrial-grade propylene glycol methyl ether are fed into the upper and middle parts of the first azeotropic distillation tower, respectively. Cyclohexane is preheated to 20-40° C. in a preheater, and industrial-grade propylene glycol methyl ether is preheated to 30-50° C. in a preheater;

[0044] The first azeotropic distillation tower has 30 to 40 plates, an operating reflux ratio of 0.8 to 2, preferably in the range of 0.8 to 1.5, and a tower top pressure of 0.1 to 0.3 MPa. The tower top discharge is water and cyclohexane, the temperature is stabilized at 70°C to 80°C, and the tower bottom discharge is a crude product of propylene glycol methyl ether, including 2-methoxy-1-propanol, and the temperature is stabilized at 140°C to 150°C.

[0045] The mass flow rate ratio of the industrial-grade propylene glycol methyl ether to cyclohexane is 1:2 to 1:4.

[0046] In order to facilitate the recovery of cyclohexane and improve economic efficiency, a cyclohexane storage tank is connected to the tower top outlet pipeline, and the cyclohexane can be recycled as an azeotropic agent feed after subsequent separation from water.

[0047] (2) The crude product of propylene glycol methyl ether enters the second distillation tower to remove 2-methoxy-1-propanol.

[0048] The number of plates of the second distillation tower is 35 to 45, the top pressure is 10 KPa to 200 KPa, the ratio of the mass flow rate of the top distillate to the mass flow rate of the feed is 0.6:1 to 0.9:1, the top discharge is 99.99% propylene glycol methyl ether, the top temperature is stable at 50 to 60°C, the bottom discharge is 2-methoxy-1-propanol, and the bottom temperature is stable at 60 to 70°C.

[0049] In order to facilitate the collection of 2-methoxy-1-propanol, a 2-methoxy-1-propanol storage tank is connected to a discharge pipeline of the second distillation tower kettle.

[0050] In order to facilitate reflux, a reflux tank is provided to be connected to a pipeline of a discharge port at the top of the second distillation tower, and the reflux tank is connected to a three-way valve and the first mixed resin column through a pipeline.

[0051] (3) The top product of the second distillation tower enters the first mixed resin column through a feed pump. The filler in the column is a uniform mixture of strongly acidic cation exchange resin and strongly basic anion exchange resin, the mass ratio of the two is 0.8-1.5, the filler height-diameter ratio is 3-6, the feed flow rate is 10-20 BV / h, preferably, the resin particle size is 0.2-0.4, the uniformity coefficient is 1.3-1.5, and when the resin column adsorbs to a point close to the breakthrough point, it is switched to another identical resin column in parallel through a three-way valve.

[0052] The anion and cation exchange resins are both styrene-based resins.

[0053] The three-way valve, the connecting pipeline between the propylene glycol methyl ether storage tank and the first mixed resin column, and the first resin column are all made of PFA material.

[0054] (4) After the crude propylene glycol methyl ether passes through the first mixed resin column to remove most of the anions and most of the metal cations, it then enters the second resin column through a three-way valve to further remove ionic impurities. The filler in the second resin column is a macroporous resin with a height-to-diameter ratio of 3 to 6 and a flow rate of 10 to 20 BV / h. Preferably, the resin particle size is 0.4 to 0.6 and the resin uniformity coefficient is 1.0 to 1.2. When the resin column adsorbs to a point close to the breakthrough point, it is switched to another identical resin column in parallel through a three-way valve. The discharge product of the second resin column enters the middle tank.

[0055] The three-way valve, the connecting pipeline between the first mixed resin column and the second resin column, and the second resin column are all made of PFA material.

[0056] (5) The propylene glycol methyl ether in the middle tank enters the membrane separator to further remove tiny solid particles.

[0057] The separation membrane used in the membrane separator is a polytetrafluoroethylene membrane with a membrane pore diameter of 0.1 to 1 μm.

[0058] The specific operation process is as follows:

[0059] (1) Cyclohexane and industrial-grade propylene glycol methyl ether are fed into the upper and middle parts of the first azeotropic distillation tower, respectively. Cyclohexane is preheated to 40.0° C. in a preheater, and industrial-grade propylene glycol methyl ether is preheated to 30.0° C. in a preheater;

[0060] The first azeotropic distillation tower has 30 plates, an operating reflux ratio of 1, preferably in the range of 0.8 to 1.5, and a top pressure of 0.2 MPa. The top discharge is water and cyclohexane, the temperature is stabilized at 76.5°C, and the bottom discharge is a crude product of propylene glycol methyl ether, including 2-methoxy-1-propanol, and the temperature is stabilized at 144.6°C.

[0061] The mass flow rate ratio of the industrial-grade propylene glycol methyl ether to cyclohexane is 1:3.

[0062] In order to facilitate the recovery of cyclohexane and improve economic efficiency, a cyclohexane storage tank is connected to the tower top outlet pipeline, and the cyclohexane can be recycled as an azeotropic agent feed after subsequent separation from water.

[0063] (2) The crude product of propylene glycol methyl ether enters the second distillation tower to remove 2-methoxy-1-propanol.

[0064] The number of plates of the second distillation tower is 40, the top pressure is 10KPa, the mass flow rate ratio of the top distillate to the feed mass flow rate is 0.85:1, the top discharge is 99.99% propylene glycol methyl ether, the top temperature is stable at 59.6°C, the bottom discharge is 2-methoxy-1-propanol, and the bottom temperature is stable at 66.5°C.

[0065] In order to facilitate the collection of 2-methoxy-1-propanol, a 2-methoxy-1-propanol storage tank is connected to a discharge pipeline of the second distillation tower kettle.

[0066] In order to facilitate reflux, a reflux tank is provided to be connected to a pipeline of a discharge port at the top of the second distillation tower, and the reflux tank is connected to a three-way valve and the first mixed resin column through a pipeline.

[0067] (3) The top product of the second distillation tower enters the first mixed resin column through a feed pump. The filler in the column is a uniform mixture of strongly acidic cation exchange resin and strongly basic anion exchange resin, the mass ratio of the two is 1.2, the filler height-diameter ratio is 6, the feed flow rate is 15 BV / h, and preferably, the resin particle size is 0.2-0.4, and the uniformity coefficient is 1.3-1.5. When the resin column is adsorbed to a point close to the breakthrough point, it is switched to another identical resin column in parallel through a three-way valve.

[0068] The anion and cation exchange resins are both styrene-based resins.

[0069] The three-way valve, the connecting pipeline between the propylene glycol methyl ether storage tank and the first mixed resin column, and the first resin column are all made of PFA material.

[0070] (4) After the crude propylene glycol methyl ether passes through the first mixed resin column to remove most of the anions and most of the metal cations, it then enters the second resin column through a three-way valve to further remove ionic impurities. The filler in the second resin column is a macroporous resin with a height-to-diameter ratio of 6 and a flow rate of 15 BV / h. Preferably, the resin particle size is 0.4-0.6 and the resin uniformity coefficient is 1.0-1.2. When the resin column adsorbs to a point close to the breakthrough point, it is switched to another identical resin column in parallel through a three-way valve. The discharge product of the second resin column enters the middle tank.

[0071] The three-way valve, the connecting pipeline between the first mixed resin column and the second resin column, and the second resin column are all made of PFA material.

[0072] (5) The propylene glycol methyl ether in the middle tank enters the membrane separator to further remove tiny solid particles.

[0073] The separation membrane used in the membrane separator is a polytetrafluoroethylene membrane with a membrane pore diameter of 0.1 μm.

[0074] Through the above process, most metal ion concentrations in industrial-grade propylene glycol methyl ether can be purified to below 0.1 ppb, the acidity is lower than 0.01% (in terms of Hac), and the water content is less than 40 ppm. The purification results of the application example are shown in the table below.

[0075] Industrial Grade PGME Electronic Grade PGME Propylene glycol methyl ether (PGME) / wt% 23.4 99.99 Water, wt% 72.7 0.002 2-Methoxy-1-propanol / wt% 3.9 0.008 <![CDATA[Na + / ppt]]> 603200 53 <![CDATA[K + / ppt]]> 321500 91 <![CDATA[Fe 3+ / ppt]]> 178400 61 <![CDATA[Ca 2+ / ppt]]> 189300 23 <![CDATA[Li + / ppt]]> 83270 32 <![CDATA[Mg 2+ / ppt]]> 127400 42 <![CDATA[Cu 2+ / ppt]]> 36760 81 <![CDATA[Al 3+ / ppt]]> 51400 78 <![CDATA[Cr 3+ / ppt]]> 56340 61 <![CDATA[Mn 2+ / ppt]]> 42750 58 <![CDATA[Ni 2+ / ppt]]> 71650 75 >0.1μm solid particles / ml 4632 20

[0076] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A purification device for electronic grade propylene glycol methyl ether PGME, characterized in that: The purification device comprises a first azeotropic distillation tower, a second distillation tower, a three-way valve, a first mixed resin column, a second resin column, an intermediate tank and a membrane separator connected in sequence; A cyclohexane feed port is arranged at the upper portion of the first azeotropic distillation tower, and the cyclohexane feed port is sequentially connected to a cyclohexane preheater and a cyclohexane feed pump through a feed pipeline; A propylene glycol methyl ether feed port is arranged in the middle of the first azeotropic distillation tower, and the propylene glycol methyl ether feed port is connected to a propylene glycol methyl ether preheater and a propylene glycol methyl ether feed pump in sequence through a feed pipeline; The bottom discharge port of the first azeotropic distillation tower is connected to the feed port of the second distillation tower through a pipeline; the top discharge port of the second distillation tower is connected to the feed port of the first mixed resin column through a resin column feed pump, a three-way valve and a connecting pipeline; the second resin column discharge port is connected to the membrane separator through a connecting pipeline and a feed pump.

2. The purification device of electronic grade propylene glycol methyl ether PGME according to claim 1, characterized in that, The first mixed resin column and the second resin column each include two identical resin columns arranged in parallel, and a three-way valve is arranged on the connecting pipeline.

3. The purification device of electronic grade propylene glycol methyl ether PGME according to claim 1, characterized in that, The purification device also includes a cyclohexane storage tank and a 2-methoxy-1-propanol storage tank; the cyclohexane storage tank is connected to the top discharge port of the first azeotropic distillation tower through a pipeline, and the 2-methoxy-1-propanol storage tank is connected to the discharge pipeline of the bottom of the second distillation tower.

4. The purification device of electronic grade propylene glycol methyl ether PGME according to claim 1, characterized in that, The separation membrane used in the membrane separator is a polytetrafluoroethylene membrane with a membrane pore diameter of 0.1 to 1 μm.

5. The purification device of electronic grade propylene glycol methyl ether PGME according to claim 1, characterized in that, The three-way valve, the connecting pipeline between the two resin columns and the resin column material are all made of PFA or have a PFA coating on the inside.

6. The purification device of electronic grade propylene glycol methyl ether PGME according to claim 1, characterized in that, The filler in the first mixed resin column is composed of a uniform mixture of styrene-based strongly acidic cation exchange resin and styrene-based strongly basic anion exchange resin.

7. The purification device of electronic grade propylene glycol methyl ether PGME according to claim 1, characterized in that, The filler in the second resin column is composed of macroporous resin.

8. The purification device of electronic grade propylene glycol methyl ether PGME according to claim 1, characterized in that, A reflux tank is arranged on the pipeline between the top discharge port of the second distillation tower and the first mixed resin column.

9. A purification method using the purification device of electronic grade propylene glycol methyl ether PGME according to any one of claims 1 to 8, characterized in that: The steps include: (1) Cyclohexane and industrial-grade propylene glycol methyl ether are fed into the upper and middle parts of the first azeotropic distillation tower, respectively. Cyclohexane is preheated to 20-40° C. in a preheater, and industrial-grade propylene glycol methyl ether is preheated to 30-50° C. in a preheater; The first azeotropic distillation tower has 30 to 40 plates, an operating reflux ratio of 0.8 to 2, and a top pressure of 0.1 to 0.3 MPa; the top discharge is water and cyclohexane, the temperature is stabilized at 70°C to 80°C, and the bottom discharge is a crude product of propylene glycol methyl ether, including 2-methoxy-1-propanol, and the temperature is stabilized at 140°C to 150°C; The mass flow rate ratio of the industrial-grade propylene glycol methyl ether to cyclohexane is 1:2 to 1:4; (2) The crude product of propylene glycol methyl ether enters the second distillation tower to remove 2-methoxy-1-propanol The second distillation tower has 35 to 45 plates, a top pressure of 10 KPa to 200 KPa, a ratio of the mass flow rate of the top distillate to the mass flow rate of the feed of 0.6:1 to 0.9:1, a top discharge of 99.99% propylene glycol methyl ether, a top temperature of 50 to 60° C., a bottom discharge of 2-methoxy-1-propanol, and a bottom temperature of 60 to 70° C.; (3) The top product of the second distillation tower enters the first mixed resin column through a feed pump. The filler in the column is a uniform mixture of strongly acidic cation exchange resin and strongly basic anion exchange resin, the mass ratio of the two is 0.8-1.5, the filler height-diameter ratio is 3-6, the feed flow rate is 10-20 BV / h, the resin particle size is 0.2-0.4, and the uniformity coefficient is 1.3-1.

5. When the resin column adsorbs to a point close to the breakthrough point, it is switched to another identical resin column in parallel through a three-way valve; (4) the crude propylene glycol methyl ether passes through the first mixed resin column to remove most of the anions and most of the metal cations, and then enters the second resin column through a three-way valve to further remove ionic impurities; The filler in the second resin column is a macroporous resin with a height-to-diameter ratio of 3-6, a flow rate of 10-20 BV / h, a resin particle size of 0.4-0.6, and a resin uniformity coefficient of 1.0-1.

2. When the resin column adsorbs close to the penetration point, it is switched to another identical resin column in parallel through a three-way valve; the discharge product of the second resin column enters the middle tank; (5) Propylene glycol methyl ether in the middle tank enters the membrane separator to further remove tiny solid particles; The separation membrane used in the membrane separator is a polytetrafluoroethylene membrane with a membrane pore diameter of 0.1 to 1 μm.

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