Device for industrial production of glycidol and production method thereof

Abstract

The invention discloses a device for industrial production of glycidol and a production method thereof, the top of a reaction kettle is provided with a liquid alkali solution continuous feeding hole and is connected with an azeotropic rectifying tower, the bottom of the reaction kettle is provided with a reaction liquid outlet, and the top of the azeotropic rectifying tower is provided with a gas phase outlet; a gas phase outlet is sequentially connected with a second condenser and a liquid-liquid layering device, an organic phase outlet of the liquid-liquid layering device is connected with a liquid distributor at the top of the azeotropic rectifying tower, and a water phase outlet of the liquid-liquid layering device is connected with a solvent recovery tower; an inlet of the centrifugal filtering device is connected with a reaction liquid outlet of the reaction kettle; a filtrate outlet is connected with an inlet of the wiped-film evaporation device; an organic phase outlet is formed in the top of the wiped-film evaporation device and connected with an inlet of the first condenser, and a heavy component discharge port is formed in the bottom of the wiped-film evaporation device; and an outlet of the first condenser is connected with a glycidyl rectification system. The method has the advantages of low cost, high safety coefficient, environmental protection, high product purity, high reaction yield and the like.

Description

Technical Field

[0001] The invention relates to the technical field of organic synthesis, and in particular to a device for industrial production of glycidol and a production method thereof. Background Art

[0002] Glycidol, also known as 2,3-epoxy-1-propanol and 2,3-epoxypropanol, contains two functional groups, epoxy and hydroxyl, in its molecule. It can be used as an intermediate for the synthesis of surfactants, elastomers, plastics, resins, dyes, paints, etc. It can also be widely used in the extraction and separation of various solvents. Its derivatives are industrial raw materials for pesticides, plastics, resins, medicines and additives.

[0003] The commercial methods known at home and abroad for preparing glycidol include allyl alcohol oxidation and 3-chloro-1,2-propylene glycol low-temperature dehydrochlorination. Among them, the allyl alcohol oxidation method uses allyl alcohol and hydrogen peroxide as raw materials, and performs epoxidation under catalyst conditions to produce glycidol, but the allyl alcohol required for this route is obtained by epoxidation of propylene to propylene oxide and then isomerization, resulting in high cost of glycidol obtained by this route, and the starting raw material propylene is a non-renewable resource. And the dehydrochlorination method using 3-chloro-1,2-propylene glycol as raw material, the raw material 3-chloro-1,2-propylene glycol can be prepared by reacting glycerol with hydrogen chloride, glycerol is a raw material that can be derived from biological, low cost, high sustainable development, so the glycidol industrial development of this route has an increasingly important green development prospect. The traditional 3-chloro-1,2-propylene glycol dehydrochlorination method uses dichloromethane as solvent, adds solid sodium hydroxide to react, and the crude product obtained by the reaction is filtered and desalted, and then distilled under reduced pressure to obtain glycidol. This method involves the addition of solid materials in the industrial process, which makes it difficult to achieve continuous and large-scale production. The reaction system involves a solid phase, and the dissolution of the solid takes time, resulting in a long reaction time. In addition, glycidol is prone to self-polymerization in the presence of acids, bases or salts. Long reaction time will seriously reduce the yield of glycidol and even cause safety accidents.

[0004] The Chinese invention patent with the publication number of CN103012322A provides a method for synthesizing glycidol, wherein dichloromethane is used as a solvent, 40% sodium hydroxide solution and a catalytic amount of tetrabutylammonium chloride react with 3-chloro-1,2-propylene glycol at 80°C, and anhydrous calcium chloride is used for dehydration and drying after the reaction is completed. Under this temperature condition, the presence of a large amount of water and metal ions will lead to significant ring-opening degradation of glycidol, and the dehydration operation of a large amount of anhydrous calcium chloride does not have the operability of large-scale industrial production, and the production and processing costs are high. The Korean patent (KR2004 / 002093) uses fine-grained phosphate to replace sodium hydroxide, and still uses dichloromethane as a solvent. The obtained solution is desalted and distilled under reduced pressure to obtain glycidol. Since water is generated during the reaction process, this method still contains a small amount of salt in the crude product during reduced pressure distillation, and the problem of ring-opening self-polymerization of glycidol in the presence of salts is still not solved during the distillation process. At the same time, the addition of phosphate is still solid addition, which is difficult to achieve continuous production in industry. The Chinese invention patent with publication number CN106588820A provides a method for preparing glycidol, which uses 3-chloro-1,2-propylene glycol and a 95% ethanol solution of sodium hydroxide to react, and after the reaction is completed, centrifugal filtration is performed to remove most of the sodium chloride solid, and then the crude product is concentrated by multiple short-path thin film evaporation to obtain glycidol. Although this method avoids the hydrolysis problem of glycidol in the presence of a large amount of water and metal salts, it still has many disadvantages. First, it still cannot avoid the problem of the operationality of feeding solid sodium hydroxide and its slow dissolution in ethanol. Secondly, due to Since 95% ethanol is used as the solvent and water is generated during the reaction, the composition of the solution (water content greater than 5%) is located on the composition side of the lowest azeotropic point of the azeotropic system of ethanol and water (95.6% ethanol and 4.4% water) and water. Ordinary distillation cannot completely remove the water in the bottom of the tower. Therefore, after multiple thin-film evaporation concentrations, the glycerol product still contains about 1% water. Therefore, there are still a few metal salts in the glycerol product that cannot be removed, which not only leads to a decrease in the yield of glycidol during the evaporation process, but also brings safety risks to the long-term stable storage of the product. The Chinese invention patent with publication number CN104844463A provides a green synthesis method for high-purity 3-methylamino-1,2-propanediol, in which 3-chloro-1,2-propanediol and a methanol solution of sodium methoxide are reacted in a tower reactor. After the reaction, most of the sodium chloride solids are removed by centrifugal filtration, and then the crude product is passed through an intermittent distillation device to obtain a glycidol product. Although this method avoids the problem of sodium hydroxide feeding and dissolution, the cost of sodium methoxide is higher than that of sodium hydroxide. In addition, since water is generated during the reaction, methanol is evaporated first during the intermittent purification process. The remaining water in the intermittent distillation kettle and the metal salts dissolved in the water will cause the ring-opening self-polymerization of glycidol, reducing the yield of glycidol and posing a safety risk. Summary of the invention

[0005] The purpose of the present invention is to provide a device for industrial production of glycidol and a production method thereof, which has the advantages of easy continuous production, easy availability of raw materials, low cost, high safety factor, low reaction temperature, high reaction purity and yield, and solves the above problems existing in the prior art.

[0006] The invention discloses a device for industrial production of glycidol, comprising a reactor, a centrifugal filter, a scraped film evaporator, a first condenser, a glycidol distillation system and a solvent recovery tower. The reactor is provided with a mechanical stirring device. The reactor is provided with a continuous feed port for a liquid alkali solution at the top and connected to an azeotropic distillation tower, and a reaction liquid outlet is provided at the bottom. The azeotropic distillation tower is provided with a gas phase outlet at the top, which is sequentially connected to a second condenser and a liquid-liquid separator. The organic phase outlet of the liquid-liquid separator is connected to a liquid distributor at the top of the azeotropic distillation tower, and the water phase outlet of the liquid-liquid separator is connected to the solvent recovery tower. The inlet of the centrifugal filter is connected to the reaction liquid outlet of the reactor, and the filtrate outlet is connected to the inlet of the scraped film evaporator. The top of the scraped film evaporator is provided with an organic phase outlet, which is connected to the inlet of the first condenser, and the bottom of the scraped film evaporator is provided with a heavy component discharge outlet. The outlet of the first condenser is connected to the glycidol distillation system, which is a glycidol continuous distillation system or a glycidol intermittent distillation tower.

[0007] Furthermore, the glycidol continuous distillation system comprises a light component removal tower, a glycidol refining tower and a propylene glycol recovery tower which are connected in sequence, the light component removal tower is used to remove the azeotropic solvent, the azeotropic solvent is extracted from the top of the light component removal tower, the bottom material of the light component removal tower enters the glycidol refining tower, the glycidol refining tower is used to extract high-purity glycidol from the top, and the purity of glycidol can reach more than 99.0%, the bottom material of the glycidol refining tower enters the propylene glycol recovery tower, the propylene glycol recovery tower is used to recover excess 3-chloro-1,2-propylene glycol reactant, and the bottom of the propylene glycol recovery tower is the distillation residue.

[0008] Furthermore, the internals of the glycidol refining tower use low pressure drop structured packing or random packing suitable for high vacuum, including but not limited to structured BX wire mesh packing. Through the above selection, the kettle temperature can be reduced and the yield of glycidol can be increased.

[0009] The present invention also provides an industrial production method of glycidol, comprising the following steps:

[0010] S1, the azeotropic solvent and 3-chloro-1,2-propylene glycol are mixed in a reactor in a molar ratio of 0.50-2.5:1, and then an aqueous solution of sodium hydroxide is continuously added dropwise to the system under vacuum, wherein the molar ratio of 3-chloro-1,2-propylene glycol to sodium hydroxide is 1.01-1.30:1, and more preferably, the molar ratio of the two is 1.05-1.15:1, the reaction temperature is 10-40 ° C, and the reaction residence time is 0.5-3 hours, keeping the system in a boiling reflux state to react and remove water simultaneously; within the above temperature range, the higher the temperature, the shorter the corresponding required reaction residence time, if the temperature is lower than this scope, the reaction speed is too slow; the temperature is higher than this scope, which will lead to an increase in by-products; the residence time of the reaction is too long, which will lead to a series of cascade reactions of glycidol;

[0011] S2, the reactor is connected to the azeotropic distillation tower, the gas phase generated during boiling reflux enters the azeotropic distillation tower from the reactor for further condensation, and then enters the liquid-liquid separator for stratification, the upper organic phase is returned to the azeotropic distillation tower in a reflux manner, and the lower water phase enters the solvent recovery tower to recover the azeotropic solvent;

[0012] S3. After the reaction is completed, the reaction solution is centrifuged and filtered, and the obtained filtrate enters the scraped film evaporator and evaporates under high vacuum to obtain an organic phase and a heavy component, and the heavy component is discharged from the bottom of the scraped film evaporator;

[0013] S4. The organic phase is evaporated from the top of the scraped film evaporator and then condensed and enters the glycidol distillation system for refining to obtain the glycidol product.

[0014] Furthermore, the azeotropic distillation tower is a distillation tower with reflux and internal fillers, and the refluxed organic phase enters the azeotropic distillation tower through a liquid distributor at the top of the azeotropic distillation tower for reuse.

[0015] Furthermore, the solvent recovery tower is a continuous distillation tower or an intermittent distillation tower, and the water after recovering the azeotropic solvent is discharged into the sewage system or reused as reclaimed water.

[0016] Furthermore, the azeotropic solvent includes n-butanol, sec-butanol, isobutanol, methyl isobutyl ketone, benzene, n-heptane, toluene, 1,2-dichloroethane, cyclohexane or a combination thereof.

[0017] Organic solvents have the following advantages: 1. They form an azeotrope with the lowest azeotropic point with water, can effectively carry water, and form an insoluble or partially miscible two-phase system with water; 2. Their boiling point at normal pressure is significantly different from that of glycidol (163°C), which is beneficial for subsequent separation from the product. Generally, the difference in boiling point between them and glycidol is not less than 15 degrees, and they do not form an azeotrope with glycidol; 3. They do not react with reactants or products under process operating conditions; 4. They have low viscosity, which is beneficial for adjusting the viscosity of the system and facilitates subsequent filtration operations.

[0018] Furthermore, the concentration of the sodium hydroxide is 30-50%. More preferably, a 30% sodium hydroxide solution commonly used in industry can be used as the reaction material.

[0019] Furthermore, in step S1, 3-chloro-1,2-propanediol has R-type or S-type optical activity, and a glycidol product with corresponding optical activity is obtained.

[0020] Furthermore, in step S4, the azeotropic solvent and 3-chloro-1,2-propanediol are recovered and reused in the reaction system.

[0021] The working principle of the present invention is as follows:

[0022]

[0023] Compared with the prior art, the beneficial technical effects of the present invention are:

[0024] The device and production method for industrial production of glycidol of the present invention adopt sodium hydroxide aqueous solution as reaction material, solve the problem of solid sodium hydroxide feeding and dissolution, easy to operate, easy to obtain raw materials, and easy to realize continuous industrial production; and the reaction process adopts azeotropic solvent to carry water, the water generated in the reaction process and the water brought in by the liquid alkali solution are removed from the system by the azeotropic solvent, the reaction system is always controlled to maintain a low water content, and the side reaction of ring-opening hydrolysis of the product glycidol under this condition is greatly reduced; wherein, the reactor is connected with the azeotropic distillation tower, the reaction temperature is low, and the side reactions such as polymerization and hydrolysis of glycidol are effectively suppressed; meanwhile, the reaction process is always in a boiling reflux state, and the heat released by the reaction can be used as a heat source of the azeotropic distillation reboiler, which is not only energy-saving, but also has a strong heat transfer capacity, increases the safety factor, reduces the thermal risk level of the reaction, and reduces the possibility of explosion; at this time, before the glycidol is refined, a scraped film evaporator is used to remove a small amount of alkali metal chloride remaining in the crude product, which greatly improves the stability of glycidol in the subsequent distillation operation stage, thereby improving the yield of glycidol (>90.0%).

[0025] The device for industrial production of glycidol and the production method thereof of the present invention can obtain glycidol of high purity (>99.0%) because water and salt are removed before refining glycidol, and the stability of glycidol under refining operation conditions is increased; moreover, the azeotropic solvent and unreacted 3-chloro-1,2-propylene glycol both achieve high recycling rates, and a small amount of solvent in wastewater is also recycled before discharge or reclaimed water reuse. The whole process is energy-saving and environmentally friendly, with little pollution to the environment, and can be used for large-scale industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0027] Figure 1 This is a schematic diagram of the process of the device for industrial production of glycidol according to Example 1 of the present invention when used for continuous production of glycidol;

[0028] Figure 2 This is a schematic diagram of the process of the device for industrial production of glycidol according to Example 2 of the present invention when used for intermittent production of glycidol.

[0029] Explanation of the reference numerals: 1. Reactor; 2. Azeotropic distillation tower; 3. Second condenser; 4. Liquid-liquid separator; 5. Centrifugal filter; 6. Wiped film evaporator; 7. First condenser; 8. Light component removal tower; 9. Glycidol refining tower; 10. Chloropropylene glycol recovery tower; 11. Solvent recovery tower; 12. Glycidol intermittent distillation tower; 13. Solvent intermittent recovery tower. DETAILED DESCRIPTION

[0030] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0031] In the description of the present invention, it should be understood that the terms "length", "width", "inside", "outside" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined.

[0032] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0033] The embodiment of the present specification provides a device for industrial production of glycidol, including a reactor 1, a centrifugal filter device 5, a scraped film evaporator 6, a first condenser 7, a glycidol distillation system and a solvent recovery tower 11, the reactor 1 has a built-in mechanical stirring device, the top of the reactor 1 is provided with a continuous feed port for a liquid alkali solution and is connected to an azeotropic distillation tower 2, the bottom is provided with a reaction liquid outlet, the top of the azeotropic distillation tower 2 is provided with a gas phase outlet, the gas phase outlet is connected to a second condenser 3 and a liquid-liquid separator 4 in sequence, and the organic phase outlet of the liquid-liquid separator 4 is connected to the azeotropic distillation tower 2. The liquid distributor at the top of the distillation tower 2 is connected, and the water phase outlet of the liquid-liquid separator 4 is connected to the solvent recovery tower 11; the inlet of the centrifugal filter device 5 is connected to the reaction liquid outlet of the reactor 1, and the filtrate outlet is connected to the inlet of the scraped film evaporation device; the top of the scraped film evaporation device is provided with an organic phase outlet, and the organic phase outlet is connected to the inlet of the first condenser 7, and the bottom of the scraped film evaporation device is provided with a heavy component discharge outlet; the outlet of the first condenser 7 is connected to the glycidol distillation system, and the glycidol distillation system is a glycidol continuous distillation system or a glycidol intermittent distillation tower 12.

[0034] The glycidol continuous distillation system comprises a light component removal tower 8, a glycidol refining tower 9 and a chloropropylene glycol recovery tower 10 which are connected in sequence. The light component removal tower 8 is used to remove the azeotropic solvent. The azeotropic solvent is extracted from the top of the light component removal tower 8. The bottom material of the light component removal tower 8 enters the glycidol refining tower 9. The glycidol refining tower 9 is used to extract high-purity glycidol from the top. The bottom material of the glycidol refining tower 9 enters the chloropropylene glycol recovery tower 10. The chloropropylene glycol recovery tower 10 is used to recover excess 3-chloro-1,2-propylene glycol reactant. The bottom of the chloropropylene glycol recovery tower 10 is the distillation residue.

[0035] In addition, as the internals of the glycidol refining tower 9, a low pressure drop structured packing or random packing suitable for high vacuum is used.

[0036] The present specification also provides an industrial production method of glycidol, comprising the following steps:

[0037] S1, the azeotropic solvent and 3-chloro-1,2-propylene glycol are mixed in a molar ratio of 0.50-2.5:1 in a reactor 1 in advance, and then an aqueous solution of sodium hydroxide is continuously added dropwise to the system under vacuum conditions, wherein the molar ratio of 3-chloro-1,2-propylene glycol to sodium hydroxide is 1.01-1.30:1, the reaction temperature is 10-40 ° C, the reaction residence time is 0.5-3 hours, and the system is kept in a boiling reflux state to react and remove water at the same time;

[0038] S2, the reactor 1 is connected to the azeotropic distillation tower 2, the gas phase generated during the boiling reflux of the system enters the azeotropic distillation tower 2 from the reactor 1 for further condensation, and then enters the liquid-liquid separator 4 for stratification, the upper organic phase is returned to the azeotropic distillation tower 2 in a reflux manner, and the lower water phase enters the solvent recovery tower 11 to recover the azeotropic solvent;

[0039] S3, after the reaction is completed, the reaction solution is centrifuged and filtered, and the obtained filtrate enters the scraped film evaporator, and evaporates under high vacuum to obtain an organic phase and a heavy component, and the heavy component is discharged from the bottom of the scraped film evaporator 6;

[0040] S4, the organic phase is evaporated from the top of the scraped film evaporator 6 and then condensed and enters the glycidol distillation system for refining to obtain the glycidol product.

[0041] The solvent recovery tower 11 is a continuous distillation tower or an intermittent distillation tower, and the water after recovering the azeotropic solvent is discharged into the sewage system or reused as reclaimed water.

[0042] Optionally, the azeotropic solvent includes n-butanol, sec-butanol, isobutanol, methyl isobutyl ketone, benzene, n-heptane, toluene, 1,2-dichloroethane, cyclohexane or a combination thereof.

[0043] Preferably, the concentration of sodium hydroxide is 30-50%.

[0044] Furthermore, in step S1, 3-chloro-1,2-propanediol has R-type or S-type optical activity, and a glycidol product with corresponding optical activity is obtained.

[0045] Preferably, in step S4, the azeotropic solvent and 3-chloro-1,2-propanediol are recovered and reused in the reaction system.

[0046] The device for industrial production of glycidol and the production method thereof adopt sodium hydroxide aqueous solution as the reaction material, solve the problem of solid sodium hydroxide feeding and dissolution, are easy to operate, and the raw materials are easily available, and it is easy to realize continuous industrial production; and the reaction process adopts azeotropic solvent to carry water, and the water generated in the reaction process and the water brought in by the liquid alkali solution are removed from the system by the azeotropic solvent, and the reaction system is always controlled to maintain a low water content, which greatly reduces the side reaction of ring-opening hydrolysis of the product glycidol under this condition; wherein the reactor 1 is connected to the azeotropic distillation tower 2, the reaction temperature is low, and the side reactions such as polymerization and hydrolysis of glycidol are effectively suppressed; meanwhile, the reaction process is always in a boiling reflux state, and the heat released by the reaction can be used as the heat source of the azeotropic distillation reboiler, which is not only energy-saving, but also has a strong heat transfer capacity, increases the safety factor, reduces the thermal risk level of the reaction, and reduces the possibility of explosion; at this time, before the glycidol is refined, a scraped film evaporator 6 is used to remove a small amount of alkali metal chloride remaining in the crude product, which greatly improves the stability of glycidol in the subsequent distillation operation stage, thereby improving the yield of glycidol.

[0047] The technical solutions provided by various embodiments of the present invention are described in detail below in conjunction with the accompanying drawings.

[0048] Example 1

[0049] like Figure 1 As shown, when the device for industrial production of glycidol of Example 1 of the present invention is used for continuous production of glycidol, it includes a reactor 1, an azeotropic distillation tower 2, a second condenser 3, a liquid-liquid separator 4, a centrifugal filter 5, a scraped film evaporator 6, a first condenser 7, a light component removal tower 8, a glycidol refining tower 9, a chloropropylene glycol recovery tower 10 and a solvent recovery tower 11, wherein the reactor 1 is provided with a mechanical stirring device, a liquid alkali solution continuous feed port is arranged at the top of the reactor 1, the top of the reactor 1 is connected with the azeotropic distillation tower 2, the top of the azeotropic distillation tower 2 is a gas phase outlet, which is connected to the second condenser 3 and the liquid-liquid separator 4, the organic phase outlet of the liquid-liquid separator 4 is connected to the liquid distributor at the top of the azeotropic distillation tower 2, the water phase outlet of the liquid-liquid separator 4 is connected to the solvent recovery tower 11, and the bottom of the reactor 1 is provided with a reaction liquid outlet.

[0050] At this time, the inlet of the centrifugal filtration device 5 is connected to the reaction liquid outlet of the reactor 1, and the filtrate outlet is connected to the inlet of the scraped film evaporation device 6; the top of the scraped film evaporation device 6 is provided with an organic phase outlet, and the organic phase outlet is connected to the inlet of the first condenser 7, and the bottom of the scraped film evaporation device 6 is provided with a heavy component discharge outlet; the outlet of the first condenser 7 is connected to the light component removal tower.

[0051] Among them, the light component removal tower 8 is used to remove the azeotropic solvent, and the azeotropic solvent is extracted from the top of the light component removal tower 8. The bottom material of the light component removal tower 8 enters the glycidol refining tower 9; the glycidol refining tower 9 is used to extract high-purity glycidol from the top, and the bottom material of the glycidol refining tower 9 enters the chloropropylene glycol recovery tower 10 for recovering excess 3-chloro-1,2-propylene glycol reactant, and the bottom is the distillation residue.

[0052] In this embodiment 1, the diameter of the azeotropic distillation tower 2 is 800 mm, and a 3-meter-long regular BX wire mesh packing (packing specific surface area 500 m 2 / m 3 ). The tower diameter of the light component removal tower 8 is 600mm, the filling of the rectifying section is BX structured packing, the height is 2.5 meters, and the height of the BX structured packing of the stripping section is 1.5 meters. The tower diameter of the glycidol refining tower 9 is 700mm, the filling of the rectifying section is BX structured packing, the height is 4 meters, and the height of the BX structured packing of the stripping section is 2.5 meters. The tower diameter of the chloropropylene glycol recovery tower 10 is 700mm, the filling of the rectifying section is BX structured packing, the height is 3 meters, and the height of the BX structured packing of the stripping section is 3 meters.

[0053] According to the following Figure 1 The process shown in the figure, the industrial production method of glycidol specifically comprises the following steps:

[0054] S1, after the reactor 1 is inerted with nitrogen, 2000Kg of 3-chloro-1,2-propylene glycol is pumped into the reactor 1 with a pump, the kettle temperature is cooled to 20°C with 5°C cooling water, and then 4200Kg of isobutanol is pumped into the reactor 1 with a pump, the 5°C cooling water valve of the second condenser 3 at the top of the azeotropic distillation tower 2 is opened, and the vacuum pump is started to reduce the pressure in the reactor 1 to 20mmHg, and then the reactor 1 is heated to maintain the kettle temperature at 20-25°C. At this time, the isobutanol begins to vaporize and the tower top is fully refluxed; 2200kg of 30% liquid caustic soda solution is dripped from the header tank at a speed of 1470kg / hr, and the entire dripping process is about 1.5 hours, and the kettle temperature is controlled at 20-25°C to keep the system in a boiling reflux state all the time.

[0055] S2, the evaporated gas phase (azeotrope of isobutanol and water) is condensed by the second condenser 3 at the top of the azeotropic distillation tower 2, and then enters the liquid-liquid separator 4 for automatic stratification. The organic phase (mainly isobutanol) on the upper layer overflows to a 2-cubic-meter receiving tank. The isobutanol in the receiving tank is refluxed into the azeotropic distillation tower 2 by a pump, and the reflux flow rate is controlled to make the liquid level in the receiving tank constant. The water phase on the lower layer of the liquid-liquid separator 4 enters a temporary storage tank, and the isobutanol in the water phase is recovered by a solvent recovery tower 11 before the water phase is discharged into the sewage system.

[0056] S3, after the reaction is completed, the reaction solution is centrifuged to remove a large amount of sodium chloride solid generated, and the filtrate enters the mother liquor tank again. Before each filter cake discharge, the filter cake is washed with 100 kg of isobutanol; after washing, a total of 600 kg of isobutanol for washing is added, all of which are incorporated into the mother liquor, totaling 5570 kg of mother liquor, and the obtained mother liquor is fed into the scraped film evaporator 6 at a feed rate of 300 kg / hr per hour to evaporate most of the organic matter, i.e., crude glycidol, also including alkali metal chloride, water, azeotropic solvent, remaining 3-chloro-1,2-propylene glycol, by-products, etc. The pressure of the scraped film evaporator 6 is 1 mmHg, and the return water temperature of the scraped film evaporator 6 is 90° C. The weight of the heavy component (raffinate) after the scraped film evaporation is about 75 kg in total, mainly composed of sodium chloride and a small amount of 3-chloro-1,2-propylene glycol.

[0057] S4, the crude product after scraping film evaporation enters light component removal tower 8 at 1500kg / hr, the tower top operating pressure is 100mmHg, the tower top temperature is about 53-54°C, the water content in isobutanol is about 2.5%, the material coming out of the tower kettle of light component removal tower 8 is pumped into glycidol refining tower 9 at a feed rate of 600kg / hr, the tower top operating pressure is 5mmHg, the tower top temperature is 44°C, and the glycidol content is greater than 99.0%; the material coming out of the tower kettle of glycidol refining tower 9 enters chloropropylene glycol recovery tower 10 at a feed rate of 120kg / hr, the tower top operating pressure is 1mmHg, the tower top temperature is 71°C, and the chloropropylene glycol content obtained at the tower top is about 88%.

[0058] According to calculation, the molar yield of glycidol in Example 1 relative to 3-chloro-1,2-propanediol was 93%.

[0059] Example 2

[0060] like Figure 2As shown, when the device for industrial production of glycidol of Example 2 of the present invention is used for intermittent production of glycidol, it includes a reactor 1, an azeotropic distillation tower 2, a second condenser 3, a liquid-liquid separator 4, a centrifugal filter 5, a scraped film evaporator 6, a first condenser 7, a glycidol intermittent distillation tower 12 and a solvent intermittent recovery tower 13, wherein the reactor 1 is provided with a mechanical stirring device, a liquid alkali solution continuous feed port is arranged at the top of the reactor 1, the top of the reactor 1 is connected with the azeotropic distillation tower 2, the top of the azeotropic distillation tower 2 is a gas phase outlet, which is connected to the second condenser 3 and the liquid-liquid separator 4, the organic phase outlet of the liquid-liquid separator 4 is connected to the liquid distributor at the top of the azeotropic distillation tower 2, the water phase outlet of the liquid-liquid separator 4 is connected to the solvent intermittent recovery tower 13, and the bottom of the reactor 1 is provided with a reaction liquid outlet.

[0061] At this time, the inlet of the centrifugal filter device 5 is connected to the reaction liquid outlet of the reactor 1, and the filtrate outlet is connected to the inlet of the scraped film evaporator 6; an organic phase outlet is arranged at the top of the scraped film evaporator 6, and the organic phase outlet is connected to the inlet of the first condenser 7, and a heavy component discharge outlet is arranged at the bottom of the scraped film evaporator 6; the outlet of the first condenser 7 is connected to the glycidol intermittent distillation tower 12.

[0062] In this embodiment 2, the diameter of the azeotropic distillation tower 2 is 800 mm, and a 3-meter-long regular BX wire mesh packing (packing specific surface area 500 m 2 / m 3 )

[0063] According to the following Figure 2 The process shown in the figure, the industrial production method of glycidol specifically comprises the following steps:

[0064] S1, after the reactor 1 is inerted with nitrogen, 2000Kg of 3-chloro-1,2-propylene glycol is pumped into the reactor 1 with a pump, the kettle temperature is cooled to 20°C with 5°C cooling water, and then 4200Kg of isobutanol is pumped into the reactor 1 with a pump, the 5°C cooling water valve of the second condenser 3 at the top of the azeotropic distillation tower 2 is opened, and the vacuum pump is started to reduce the pressure in the reactor 1 to 20mmHg, and then the reactor 1 is heated to maintain the kettle temperature at 20-25°C. At this time, the isobutanol begins to vaporize and the tower top is fully refluxed; 2200kg of 30% liquid caustic soda solution is dripped from the header tank at a speed of 1470kg / hr, and the entire dripping process is about 1.5 hours, and the kettle temperature is controlled at 20-25°C to keep the system in a boiling reflux state all the time.

[0065] S2, the evaporated gas phase (azeotrope of isobutanol and water) is condensed by the second condenser 3 at the top of the azeotropic distillation tower 2, and then enters the liquid-liquid separator 4 for automatic stratification. The organic phase (mainly isobutanol) on the upper layer overflows to a 2-cubic-meter receiving tank. The isobutanol in the receiving tank is refluxed into the azeotropic distillation tower 2 by a pump, and the reflux flow rate is controlled to make the liquid level in the receiving tank constant. The water phase on the lower layer of the liquid-liquid separator 4 enters a temporary storage tank, and the isobutanol in the water phase is recovered by a solvent intermittent recovery tower 13 before the water phase is discharged into the sewage system.

[0066] S3, after the reaction is completed, the reaction solution is centrifuged to remove a large amount of sodium chloride solid generated, and the filtrate enters the mother liquor tank again. Before each filter cake discharge, the filter cake is washed with 100 kg of isobutanol; after washing, a total of 600 kg of isobutanol for washing is added, all of which are incorporated into the mother liquor, totaling 5570 kg of mother liquor, and the obtained mother liquor is fed into the scraped film evaporator 6 at a feed rate of 300 kg / hr per hour to evaporate most of the organic matter, i.e., crude glycidol, also including alkali metal chloride, water, azeotropic solvent, remaining 3-chloro-1,2-propylene glycol, by-products, etc. The pressure of the scraped film evaporator 6 is 1 mmHg, and the return water temperature of the scraped film evaporator 6 is 90° C. The weight of the heavy component (raffinate) after the scraped film evaporation is about 75 kg in total, mainly composed of sodium chloride and a small amount of 3-chloro-1,2-propylene glycol.

[0067] S4, the obtained crude glycidol (about 5495Kg) is pumped into the glycidol intermittent distillation tower 12 for refining, steam is introduced into the distillation kettle jacket, the material in the kettle is heated, and a water ring pump is used to evacuate, and isobutanol is recovered at 100mmHg; when the tower top temperature is 60°C and the vacuum is 100mmHg, isobutanol is recovered at the tower top, wherein the water content is 1.1%, when the top temperature begins to rise, the Roots vacuum pump is started, and the vacuum is evacuated to 10mmHg, and the reflux ratio is 9:1. The fraction obtained at this stage is the front fraction, when the top temperature is 56-57°C and the vacuum is 10mmHg, the reflux ratio is 1.5:1, and the finished glycidol is recovered, and its purity is greater than 99.0%, when the top temperature begins to rise, the vacuum is evacuated to 1mmHg, and the material is fully discharged. The fraction obtained at this stage is the rear fraction, and the front and rear fractions are all used for the next batch of distillation.

[0068] According to calculation, the molar yield of glycidol in Example 2 relative to 3-chloro-1,2-propanediol was 92%.

[0069] The device for industrial production of glycidol and the production method thereof of the present invention remove water and salt before refining the glycidol, thereby increasing the stability of the glycidol under refining operation conditions and obtaining high-purity glycidol; in addition, the azeotropic solvent and unreacted 3-chloro-1,2-propylene glycol both achieve high recycling rates, and a small amount of solvent in the wastewater is also recycled before being discharged or recycled water is reused. The whole process is energy-saving and environmentally friendly, with little pollution to the environment, and can be used for large-scale industrial production.

[0070] The embodiments described above are only descriptions of the preferred modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A device for industrial production of glycidol, It is characterized in that The invention comprises a reactor, a centrifugal filter, a scraped film evaporator, a first condenser, a glycidol distillation system and a solvent recovery tower, wherein the reactor is built with a mechanical stirring device, a liquid alkali solution continuous feed port is arranged at the top of the reactor and is connected to an azeotropic distillation tower, a reaction liquid outlet is arranged at the bottom, a gas phase outlet is arranged at the top of the azeotropic distillation tower, the gas phase outlet is connected to a second condenser and a liquid-liquid separator in sequence, an organic phase outlet of the liquid-liquid separator is connected to a liquid distributor at the top of the azeotropic distillation tower, and a water phase outlet of the liquid-liquid separator is connected to the solvent recovery tower; the inlet of the centrifugal filter is connected to the reaction liquid outlet of the reactor, and the filtrate outlet is connected to the inlet of the scraped film evaporation device; an organic phase outlet is arranged at the top of the scraped film evaporation device, the organic phase outlet is connected to the inlet of the first condenser, and a heavy component discharge outlet is arranged at the bottom of the scraped film evaporation device; the outlet of the first condenser is connected to the glycidol distillation system, and the glycidol distillation system is a glycidol continuous distillation system or a glycidol intermittent distillation tower.

2. A device for industrial production of glycidol according to claim 1, It is characterized in that The glycidol continuous distillation system comprises a light component removal tower, a glycidol refining tower and a chloropropylene glycol recovery tower which are connected in sequence. The light component removal tower is used to remove the azeotropic solvent, the azeotropic solvent is extracted from the top of the light component removal tower, the bottom material of the light component removal tower enters the glycidol refining tower, the glycidol refining tower is used to extract high-purity glycidol from the top, the bottom material of the glycidol refining tower enters the chloropropylene glycol recovery tower, the chloropropylene glycol recovery tower is used to recover excess 3-chloro-1,2-propylene glycol reactant, and the bottom of the chloropropylene glycol recovery tower is the distillation residue.

3. A device for industrial production of glycidol according to claim 2, It is characterized in that The internals of the glycidol refining tower use low pressure drop structured packing or random packing suitable for high vacuum.

4. A method for industrial production of glycidol, It is characterized in that The steps include: S1, the azeotropic solvent and 3-chloro-1,2-propylene glycol are mixed in a reactor in a molar ratio of 0.50-2.5:1, and then an aqueous solution of sodium hydroxide is continuously added dropwise to the system under vacuum conditions, wherein the molar ratio of 3-chloro-1,2-propylene glycol to sodium hydroxide is 1.01-1.30:1, the reaction temperature is 10-40 ° C, the reaction residence time is 0.5-3 hours, and the system is kept in a boiling reflux state to react and remove water at the same time; S2, the reactor is connected to the azeotropic distillation tower, the gas phase generated during boiling reflux enters the azeotropic distillation tower from the reactor for further condensation, and then enters the liquid-liquid separator for stratification, the upper organic phase is returned to the azeotropic distillation tower in a reflux manner, and the lower water phase enters the solvent recovery tower to recover the azeotropic solvent; S3. After the reaction is completed, the reaction solution is centrifuged and filtered, and the obtained filtrate enters the scraped film evaporator and evaporates under high vacuum to obtain an organic phase and a heavy component, and the heavy component is discharged from the bottom of the scraped film evaporator; S4. The organic phase is evaporated from the top of the scraped film evaporator and then condensed and enters the glycidol distillation system for refining to obtain the glycidol product.

5. A method for industrial production of glycidol according to claim 4, It is characterized in that The solvent recovery tower is a continuous distillation tower or an intermittent distillation tower, and the water after recovering the azeotropic solvent is discharged into the sewage system or reused as reclaimed water.

6. A method for industrial production of glycidol according to claim 4, It is characterized in that The azeotropic solvent includes n-butanol, sec-butanol, isobutanol, methyl isobutyl ketone, benzene, n-heptane, toluene, 1,2-dichloroethane, cyclohexane or a combination thereof.

7. A method for industrial production of glycidol according to claim 4, It is characterized in that The concentration of the sodium hydroxide is 30-50%.

8. A method for industrial production of glycidol according to claim 4, It is characterized in that In the step S1, 3-chloro-1,2-propanediol has R-type or S-type optical activity, and a glycidol product with corresponding optical activity is obtained.

9. A method for industrial production of glycidol according to claim 4, It is characterized in that The azeotropic solvent and 3-chloro-1,2-propanediol recovered in step S4 are recycled to the reaction system.

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