CN101891672B - Separation and purification method and device for purifying piperidinol product from piperidone hydrogenation reaction solution - Google Patents

Abstract

The invention discloses a separation and purification method and device for purifying piperidinol products from a piperidone hydrogenation reaction solution. The method comprises the following steps: (a) passing the crude piperidinol raw material liquid into the feed port of a piperidone recovery distillation tower , light components such as piperidone and acetonin are discharged from the top of the piperidone recovery distillation tower and then partially refluxed after being condensed by the recovery condenser; The material extracted from the bottom of the tower is sent to the feed port of the piperidine alcohol rectification tower, and the gas phase piperidine alcohol is extracted at the top of the piperidine alcohol rectification tower. The product is recovered, and the residual part of the still discharged from the bottom of the piperidine alcohol rectification tower is heated by the reboiler at the bottom of the piperidine alcohol rectification tower to form a gas phase and return to the tower, while part of it is discharged as waste liquid. By adopting the method, a high-purity piperidinol product (more than 99.5 percent by mass) can be obtained at one time, and the piperidinone product can be recovered.

Description

Separation and purification method and device for purifying piperidinol product from piperidone hydrogenation reaction solution

technical field

The invention relates to a separation and purification method for purifying piperidinol products from a piperidone hydrogenation reaction solution, and also relates to a separation and purification device for purifying piperidinol products from a piperidone hydrogenation reaction solution.

Background technique

Traditional piperidinol (2,2,6,6-tetramethyl-4-piperidinol) production technology as shown in Figure 1 is to use acetone as basic raw material earlier, obtain piperidone after reaction, and then After hydrogenation of piperidone (2,2,6,6-tetramethyl-4-piperidone), the crude product of piperidinol is obtained, that is, a kind of piperidinol, piperidone and acetonin involved in the present invention, etc. The mixed solution of the components undergoes the first crystallization after simple removal of alcohol (at this time, the mass percentage of piperidinol is about 90%) to obtain 95%-97% of piperidinol. Then, after secondary crystallization, more than 99.5% of the product can be finally obtained. Due to the shortcomings of the crystallization unit, such as long operation process, many equipment, large material loss, and high labor intensity, more piperidinol products are taken away by the crystallization mother liquor after the two crystallization processes, which will inevitably reduce the single-cycle yield of the product, and the product per ton The consumption of acetone is relatively large.

Contents of the invention

The object of the present invention is to overcome the deficiencies of the prior art, and provide a separation and purification method for purifying piperidinol products from piperidone hydrogenation reaction liquid with less consumption of raw materials, high product purity and low pollution discharge.

Another object of the present invention is to provide a separation and purification device for purifying piperidinol products from piperidone hydrogenation reaction liquid with the advantages of high efficiency, energy saving, safety and stability.

The separation and purification method of piperidinone hydrogenation reaction liquid purification piperidinol product of the present invention, it comprises the following steps:

(a) feed the crude piperidinol raw material liquid into the middle part of the piperidone recovery distillation tower, and light components such as piperidone and acetonin are discharged from the top of the piperidone recovery distillation tower and then recovered and condensed After the device is condensed, it is partly refluxed and partly extracted as piperidone product; the operating pressure at the top of the piperidone recovery distillation tower is -0.090～0.080MPa, and the pressure difference between the top and the bottom of the tower is 1～3kPa;

(b) The material extracted from the bottom of the piperidone recovery distillation tower is sent to the middle feed port of the piperidinol rectification tower, and the gas phase piperidinol is extracted at the top of the piperidine alcohol rectification tower, After the vapor phase piperidinol is condensed by the condenser, part of it is refluxed and the other part is taken out as a product, and the remaining part of the still discharged from the bottom of the piperidine alcohol rectification tower is heated by the bottom reboiler of the piperidine alcohol rectification tower After that, the gas phase is formed and returned to the tower while part of it is discharged as waste liquid. The operating pressure at the top of the piperidine alcohol rectification tower is -0.090～-0.080MPa, and the pressure difference between the top and the bottom of the tower is 2～3kPa.

The separation and purification device for purifying piperidinol products from the piperidone hydrogenation reaction liquid of the present invention comprises a piperidone recovery distillation tower and a piperidinol rectification tower, and in the piperidone recovery distillation tower and piperidinol The top of the rectifying tower is connected with a condensation and reflux device and is connected with a reboiler at the lower part of the piperidone recovery distillation tower and the piperidinol rectification tower respectively. The middle part of the tower body has a feed port respectively, and the outlet at the bottom of the piperidine recovery distillation tower is connected to the feed port of the piperidine alcohol rectification tower through a pipeline. A waste liquid pipeline is connected to the bottom of the pyridine alcohol rectification tower.

The beneficial effects of adopting the inventive method and device are:

1) By improving the traditional crystallization separation and purification process to the double-tower continuous vacuum distillation technology of the present invention, a high-purity piperidinol product (more than 99.5% by mass) can be obtained at one time, and the piperidinone product can be recovered;

2) The separation process is shortened, the separation efficiency is improved; the labor intensity of workers is reduced, and the discharge of pollutants is reduced.

3) The design method of "evaporation-condensation" condenser is adopted, which saves the consumption of cooling water, recovers the waste heat of distillation, and reduces the production cost.

4) Low pressure drop structured packing and forced circulation reboiler are used to reduce residual heat-sensitive coking in the distillation pot and increase product yield.

Description of drawings

Fig. 1 is a schematic diagram of the traditional crystallization separation process;

Fig. 2 is the schematic flow sheet of the separation and purification method of piperidinone hydrogenation reaction liquid purification piperidinol product of the present invention;

Fig. 3 is the structural representation of the "evaporation-condensation" type condenser adopted in the top of the piperidine alcohol rectifying tower in the method of the present invention.

Detailed ways

Below in conjunction with specific embodiment, and with reference to accompanying drawing, the present invention will be further described:

As shown in Figure 2, the separation and purification method of the piperidinone hydrogenation reaction solution of the present invention to purify the piperidinol product comprises the following steps: (a) usually heating the piperidinol crude raw material solution to about 70°C and passing it into Piperidone recovery distillation tower 1 middle feed port, light components such as piperidone and acetonin are discharged from the top of the piperidone recovery distillation tower, and after being condensed by recovery condenser 3, part of it is refluxed and part of it is used as piperidine The ketone product is extracted; the operating pressure at the top of the piperidone recovery distillation tower is -0.090～0.080MPa (absolute pressure), and the pressure difference between the top and the bottom of the tower is 1～3kPa; (b) from the piperidone The material extracted from the bottom of the pyridone recovery distillation tower is sent to the middle feed port of the piperidine alcohol rectification tower 4, and the gas phase piperidine alcohol is extracted at the top of the piperidine alcohol rectification tower, and the gas phase piperidine alcohol is condensed Part of it is refluxed after the device is condensed, and another part is taken out as a product at the same time, and the still residue discharged from the bottom of the piperidine alcohol rectification tower is heated by the bottom reboiler of the piperidine alcohol rectification tower to form a gas phase and return to the tower. At the same time, part of it is discharged as waste liquid. The operating pressure at the top of the piperidine alcohol rectification tower is -0.090～-0.080MPa (absolute pressure), and the pressure difference between the top and the bottom of the tower is 2～3kPa.

In the method of the present invention, the recovery condenser at the top of the piperidone recovery distillation tower is connected to the top of the tower through a gas phase line, and the liquid material condensed by the condenser enters the reflux tank, and a part is used as the necessary reflux liquid of the distillation tower. The reflux pump enters the reflux distributor at the top of the tower, and the material from the outlet of the reflux pump enters the piperidone product tank except for the reflux part. Most of the liquid phase material extracted from the liquid extraction outlet at the bottom of the piperidone recovery tower is piperidinol, only a very small part of heavy component impurities with a higher boiling point than piperidinol, and this stock is transported to piperidinol The middle inlet of the pyridine alcohol rectification tower is used as the feed of the piperidine alcohol rectification tower.

Preferably, the bottom reboiler of the piperidine alcohol rectification tower adopts forced circulation, which can speed up the flow rate of the material, thereby avoiding the solidification of the bottom material and blocking the heat exchange tube of the reboiler.

The recovery condenser of the piperidone recovery tower can use a traditional fixed tube-plate heat exchanger, and a stream of circulating cooling water can be used as the refrigerant, but the temperature at which piperidone is condensed must not be lower than 45°C, because the freezing point of piperidone It is 39°C. Below this temperature, piperidone will be solidified, block the heat exchanger, and cause an accident to stop in serious cases. Preferably, the overhead reflux of the piperidinol rectifying tower in the (b) step adopts internal reflux and the overhead condenser adopts soft water as a refrigerant. The overhead condenser of the piperidinol rectification tower is designed directly at the top of the tower, and is connected with the tower body by the cylinder flange, so that the gaseous phase materials can enter the inner channel of the condenser heat exchange tube more quickly and be condensed by the condenser The liquid material is directly returned to the uppermost part of the tower and the collector at the lower part of the condenser heat exchange tube, part of it is used as the necessary reflux liquid of the distillation tower, and the liquid enters the top liquid reflux distributor through the liquid conduit, and the other part of the liquid The extraction pipe at the top of the tower near the collector leads out of the tower and enters the piperidinol product tank.

The "soft water evaporation-condensation" condenser at the top of the piperidine alcohol rectification tower is used at the top of the piperidine alcohol tower. The condenser preferably uses 40-50°C soft water as the initial refrigerant and enters the shell side of the condenser. When the soft water absorbs heat and vaporizes under a certain pressure, it is discharged from the shell side of the condenser through the steam line welded on the upper part of the shell side. The steam pressure is 0.3-0.4MPa, which can ensure that the top operating pressure of the piperidine alcohol rectification tower is - 0.090～-0.080MPa. The reason why soft water is used is that it is not easy to scale and ensures a high heat transfer coefficient of the condenser.

The separation and purification device for purifying piperidinol products from piperidone hydrogenation reaction liquid of the present invention comprises piperidone recovery distillation tower 1 and piperidinol rectification tower 4, in the piperidone recovery distillation tower and piperidone distillation tower The tower top of pyridine alcohol rectification tower is connected with reflux device and is respectively connected with reboiler 2,5 at the lower part of the tower of piperidone recovery distillation tower and piperidin alcohol rectification tower, and in piperidone recovery distillation tower and piperidine The middle part of the alcohol rectification tower body is respectively provided with a feed port, and the bottom outlet of the piperidone recovery distillation tower is connected to the feed port of the piperidine alcohol rectification tower through a pipeline. The bottom of the piperidine alcohol rectifying tower is connected with a waste liquid pipeline.

The reflux device of the piperidone recovery distillation tower is an external reflux device.

The preferred condensation and reflux device of the piperidine alcohol rectification tower is the internal condensation and reflux device 6 . The internal condensation and reflux device may include a shell, and a plurality of heat exchange tubes 6-1 are arranged vertically in the upper part of the shell, and a water inlet 6-3 and a steam inlet 6-3 are opened on the shell. Outlet 6-2, a baffle plate is installed in the shell at the lower part of the heat exchange tube, the collector is arranged along the circumferential direction of the inner wall of the shell and the bottom wall of the collector is connected with the inner wall of the shell, close to the inner wall of the shell The deflector wall of the baffle plate set on the wall is located above the top of the collector so that the diversion liquid can flow into the collector, and the housing at the position of the collector is provided with a material extraction port 6 -4, a liquid backflow distributor 6-6 is arranged in the lower part of the housing, and the bottom of the collector communicates with the liquid backflow distributor through a guide tube 6-5, and the housing The bottom is connected with the top of the piperidine alcohol rectifying tower 4 through a cylinder flange.

Preferably, the bottom reboiler of the piperidinol rectification column is a forced circulation reboiler.

Preferably, an insulation jacket or an insulation coil is arranged outside the tower body of the piperidone recovery distillation tower and the piperidinol rectification tower, which is more suitable when the device is started and shut down.

Example 1

Heat the crude piperidinol raw material liquid to 70°C and feed it into the feed port in the middle of the piperidone recovery distillation tower 1. Light components such as piperidone and acetonin are discharged from the top of the piperidone recovery distillation tower and passed through Recovery condenser 3 condenses and partly refluxes and simultaneously partially extracts as piperidone product; the operating pressure at the top of the described piperidone recovery distillation tower is -0.090MPa (absolute pressure, the same below), and the pressure between the top and the bottom of the tower is Pressure difference is 2kPa; (b) the material that recovers from the bottom of described piperidone rectifying tower is sent into the middle part feed port of piperidinol rectifying tower 4, and is extracted at the top of described piperidinol rectifying tower tower Gas-phase piperidinol is discharged, and the gas-phase piperidinol is partially refluxed after being condensed by a condenser, and another part is extracted as a product at the same time. The reboiler at the bottom of the tower is heated to form a gas phase and returns to the tower while part of it is discharged as waste liquid. The operating pressure of the piperidine alcohol rectifying tower top is -0.085MPa (absolute pressure, the same below), and the pressure between the top and the bottom of the tower The difference is 2.5kPa. The bottom reboiler of the piperidinol rectification tower adopts forced circulation.

After testing: the quality percent purity of the piperidinol product is above 99.5%, and the piperidinone product is recovered.

Example 2

Heat the crude piperidinol raw material liquid to 72°C and feed it into the feed port in the middle of the piperidone recovery distillation tower 1. Light components such as piperidone and acetonin are discharged from the top of the piperidone recovery distillation tower and passed through Recovery condenser 3 condenses and partly refluxes and simultaneously partly extracts as piperidone product; the operating pressure at the top of the described piperidone recovery distillation tower is 0.01MPa (absolute pressure), and the pressure difference between the top and the bottom of the tower is 1kPa (b) The material extracted from the bottom of the piperidone recovery distillation tower is sent to the middle feed port of the piperidine alcohol rectification tower 4, and the gas phase piperidine is extracted at the top of the piperidine alcohol rectification tower Alcohol, the gaseous piperidine alcohol is partially refluxed after being condensed by the condenser, and the other part is extracted as a product, and the bottom of the piperidine alcohol rectification tower is reboiled at the bottom of the piperidine alcohol rectification tower. After heating, the gas phase is formed and returned to the tower while part of it is discharged as waste liquid. The operating pressure of the piperidine alcohol rectifying tower top is -0.080MPa, and the pressure difference between the tower top and the bottom of the tower is 3kPa. The bottom reboiler of the piperidinol rectification tower adopts forced circulation. The top of the piperidinol rectification tower adopts a "soft water evaporation-condensation" condenser, and the condenser uses soft water at 45°C as the initial refrigerant, which enters the shell side of the condenser. When the soft water absorbs heat and vaporizes under a certain pressure, it is discharged from the shell side of the condenser through the steam line welded to the upper part of the shell side, and the steam pressure is 0.4MPa.

After testing: the quality percentage purity of the piperidinol product is above 99.5%, and the piperidone product is recovered, and the by-product steam is 150kg/hr.

Example 3

Heat the piperidinol crude raw material liquid to 68°C and feed it into the feed port in the middle of the piperidone recovery distillation tower 1. Light components such as piperidone and acetonin are discharged from the top of the piperidone recovery distillation tower and passed through Recovery condenser 3 condenses and partly refluxes and simultaneously partially extracts as piperidone product; the operating pressure at the top of the described piperidone recovery distillation tower is 0.040MPa (absolute pressure), and the pressure difference between the top and the bottom of the tower is 3kPa (b) The material extracted from the bottom of the piperidone recovery distillation tower is sent to the middle feed port of the piperidine alcohol rectification tower 4, and the gas phase piperidine is extracted at the top of the piperidine alcohol rectification tower Alcohol, the gaseous piperidine alcohol is partially refluxed after being condensed by the condenser, and the other part is extracted as a product, and the bottom of the piperidine alcohol rectification tower is reboiled at the bottom of the piperidine alcohol rectification tower. After heating, the vapor phase is formed and returned to the tower while part of it is discharged as waste liquid. The operating pressure at the top of the piperidine alcohol rectification tower is -0.090MPa, and the pressure difference between the top and the bottom of the tower is 2kPa. The bottom reboiler of the piperidinol rectification tower adopts forced circulation. The top of the piperidinol rectification tower adopts a "soft water evaporation-condensation" condenser, and the condenser uses 50°C soft water as the initial refrigerant, which enters the shell side of the condenser. When the soft water absorbs heat and vaporizes under a certain pressure, it is discharged from the shell side of the condenser through the steam pipeline welded on the upper part of the shell side, and the steam pressure is 0.3MPa.

After testing: the quality percentage purity of the piperidinol product is above 99.5%, and the piperidone product is recovered, and the by-product steam is 150kg/hr.

Example 4

Heat the crude piperidinol raw material liquid to 70°C and feed it into the feed port in the middle of the piperidone recovery distillation tower 1. Light components such as piperidone and acetonin are discharged from the top of the piperidone recovery distillation tower and passed through Recovery condenser 3 condenses and partly refluxes and simultaneously partly extracts as piperidone product; the operating pressure at the top of the described piperidone recovery distillation tower is 0.080MPa (absolute pressure), and the pressure difference between the top and the bottom of the tower is 1.5 kPa; (b) the material taken out from the bottom of the piperidine alcohol rectification tower is sent to the middle feed port of the piperidine alcohol rectification tower 4, and the vapor phase piperidine is extracted at the top of the piperidine alcohol rectification tower tower Pyridyl alcohol, gaseous piperidine alcohol is partially refluxed after being condensed by a condenser, and another part is taken out as a product, and the remaining part of the still discharged at the bottom of the piperidine alcohol rectification tower is passed through the bottom of the piperidine alcohol rectification tower. After the boiler is heated, a gas phase is formed and returned to the tower while part of it is discharged as waste liquid. The operating pressure at the top of the piperidine alcohol rectification tower is -0.092MPa, and the pressure difference between the top and the bottom of the tower is 2kPa. The bottom reboiler of the piperidinol rectification tower adopts forced circulation. The top of the piperidinol rectification tower adopts a "soft water evaporation-condensation" condenser, and the condenser uses 40°C soft water as the initial refrigerant, which enters the shell side of the condenser. When the soft water absorbs heat and vaporizes under a certain pressure, it is discharged from the shell side of the condenser through the steam pipeline welded on the upper part of the shell side, and the steam pressure is 0.35MPa.

After testing: the quality percentage purity of the piperidinol product is above 99.5%, and the piperidone product is recovered, and the by-product steam is 150kg/hr.

Claims (7)

1. the separating and purifying method of extracting and purifying piperidinol product from piperidone hydrogenation reaction solution is characterized in that it may further comprise the steps:

(a) piperidines alcohol bullion liquid stock is fed piperidone and reclaim distillation tower middle part opening for feed, piperidone and acetonines light constituent are discharged through reclaiming the condenser condenses rear section from the cat head of said piperidone recovery distillation tower and are refluxed the while part as the extraction of piperidone product; The cat head working pressure that described piperidone reclaims distillation tower is-0.090～0.080MPa, and the pressure reduction at the bottom of cat head and the tower is 1～3kPa;

(b) material that reclaims distillation tower bottom extraction from said piperidone is sent into the middle part opening for feed of piperidines alcohol rectifying tower; At described piperidines alcohol rectifying tower cat head extraction gas phase piperidines alcohol; Gas phase piperidines alcohol refluxes while another part as the product extraction through the condenser condenses rear section; The tower bottom reboiler heating back of the pure rectifying tower of still remnants of defeated troops lease making piperidines of at the bottom of described piperidines alcohol rectifying Tata, discharging forms gas phase and returns in the tower simultaneously partly as discharging of waste liquid; Described piperidines alcohol rectifying tower top working pressure is-0.090～-0.080Mpa, the pressure reduction at the bottom of cat head and the tower is 2～3kPa.

2. the separating and purifying method of extracting and purifying piperidinol product from piperidone hydrogenation reaction solution according to claim 1 is characterized in that: the tower bottom reboiler employing pump circulation of described piperidines alcohol rectifying tower.

3. the separating and purifying method of extracting and purifying piperidinol product from piperidone hydrogenation reaction solution according to claim 1 is characterized in that: the trim the top of column of the piperidines alcohol rectifying tower in described (b) step adopts internal reflux and overhead condenser to adopt soft water as refrigerant.

4. the separation purifying plant of extracting and purifying piperidinol product from piperidone hydrogenation reaction solution; It is characterized in that: it comprises that piperidone reclaims distillation tower and piperidines alcohol rectifying tower; The cat head that reclaims distillation tower and piperidines alcohol rectifying tower at described piperidone is connected with condensation separately and is connected with reboiler respectively with reflux and in the tower bottom of piperidone recovery distillation tower and the pure rectifying tower of piperidines; The middle part of reclaiming distillation tower and piperidines alcohol rectifying tower tower body at piperidone has opening for feed; Discharge port links to each other through the opening for feed of pipeline with described piperidines alcohol rectifying tower at the bottom of the tower of described piperidone recovery distillation tower, at the bottom of the tower of described piperidines alcohol rectifying tower, is connected with the waste liquid pipeline.

5. the separation purifying plant of extracting and purifying piperidinol product from piperidone hydrogenation reaction solution according to claim 4; It is characterized in that: the reflux that described piperidone reclaims distillation tower is an external reflux device, and the condensation and the reflux of described piperidines alcohol rectifying tower are interior condensation and reflux.

6. the separation purifying plant of extracting and purifying piperidinol product from piperidone hydrogenation reaction solution according to claim 4; It is characterized in that: described condensation and reflux comprise housing; Vertically be provided with a plurality of heat transfer tubes and on housing, have water-in and vapour outlet at described housing internal upper part; In the housing of described heat transfer tube bottom, traverse baffle is housed; Scoop links to each other with described inner walls along the circumferential direction setting of inner walls and the diapire of scoop; Training wall near the traverse baffle of inner walls setting is positioned at the top at described scoop top so that the water conservancy diversion fluid power enough flows into described scoop; Be positioned at and have material extraction mouth on the housing of described scoop position and be provided with the liquid return sparger in described housing bottom, the bottom of described scoop is connected with described liquid distributor through thrust-augmenting nozzle, and described housing bottom is connected through shell flange with the cat head of piperidines alcohol rectifying tower.

7. the separation purifying plant of extracting and purifying piperidinol product from piperidone hydrogenation reaction solution according to claim 4 is characterized in that: the tower bottom reboiler of described piperidines alcohol rectifying tower is a forced circulating reboiler.

Images