CN215822383U - N-vinyl pyrrolidone purification system - Google Patents
N-vinyl pyrrolidone purification system Download PDFInfo
- Publication number
- CN215822383U CN215822383U CN202121467485.7U CN202121467485U CN215822383U CN 215822383 U CN215822383 U CN 215822383U CN 202121467485 U CN202121467485 U CN 202121467485U CN 215822383 U CN215822383 U CN 215822383U
- Authority
- CN
- China
- Prior art keywords
- nvp
- distillate
- rectification
- crystallization
- rectifying
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Landscapes
- Pyrrole Compounds (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Abstract
The utility model relates to a purification system of N-vinyl pyrrolidone, which comprises: the device comprises a first rectification unit, a first crystallization system, a third rectification unit, a second crystallization system and an NVP storage tank which are sequentially connected in series through pipelines, wherein the first rectification unit receives synthetic reaction liquid containing NVP, carries out rectification treatment and outputs a first distillate and a first kettle outlet, the first crystallization system receives the first distillate, carries out crystallization purification and outputs a first crystallization liquid, and the third rectification unit receives the first crystallization liquid, carries out rectification treatment and outputs a seventh distillate; the second rectifying unit is used for rectifying the first kettle output and outputting a second distillate, the second kettle output is returned to the first rectifying unit for rectifying, and the second crystallizing system is used for crystallizing the second distillate to obtain a second crystallized liquid; the NVP storage tank receives the seventh distillate and the second crystallization liquid. The utility model couples the cascade rectification and the gradient crystallization, can continuously refine the NVP and improve the yield of the NVP.
Description
Technical Field
The utility model belongs to the technical field of N-vinyl pyrrolidone preparation, and particularly relates to an N-vinyl pyrrolidone purification system.
Background
N-methylpyrrolidone (NVP) is a fine chemical with excellent performance, and high requirements are put on the purity of the NVP. When an acetylene synthesis method (Reppe method) is adopted to synthesize NVP, strong base such as KOH is mostly adopted as a catalyst to catalyze the vinylation reaction of a-pyrrolidone and acetylene, the method has obvious defects and multiple reaction steps, the monomer is obtained through five-step reactions such as aldehyde addition, catalytic hydrogenation, catalytic dehydrogenation cyclization, ammonolysis, alkyne addition and the like of acetylene, and the amount of nonvolatile polymerization byproducts generated in the monomer synthesis reaction process is large, so that the product post-treatment is troublesome, the yield of the target product NVP is reduced, and the separation and purification of the NVP are complicated.
At present, the NVP is separated and purified by semi-continuous separation, intermittent distillation is needed to be adopted in the last step for generating the NVP product with qualified purity, the retention time of the step is about 24-30 hours, N-vinyl pyrrolidone is a heat-sensitive substance, the retention time of materials in a rectifying tower is as high as 30-40 hours, and a large amount of N-vinyl pyrrolidone is subjected to self-polymerization in the rectifying process due to high temperature, so that the yield of the NVP target product is reduced, the production efficiency of enterprises is not high, the production cost of the enterprises is increased, and in addition, a certain environmental pollution problem is caused by self-polymerization byproducts. Therefore, a continuous refining process with better NVP separation and purification effects is found.
SUMMERY OF THE UTILITY MODEL
The utility model aims to provide a system and a method for purifying N-vinyl pyrrolidone, aiming at the defects and shortcomings of the prior art, so as to realize continuous production of high-purity N-vinyl pyrrolidone and improve the yield of a target product NVP.
To achieve the above object, the present invention provides an N-vinylpyrrolidone purification system comprising: a first rectifying unit, a first crystallizing system and a third rectifying unit which are connected in series in turn through pipelines, a second rectifying unit and a second crystallizing system which are connected in series, and an NVP storage tank, wherein,
the first rectifying unit receives a synthetic reaction liquid containing NVP (N-vinyl pyrrolidone) for rectifying and outputs a first distillate and a first kettle outlet, the first crystallization system receives the first distillate for crystallization and purification and outputs a first crystallization liquid and a first mother liquid, and the third rectifying unit receives the first crystallization liquid for rectifying and outputs a seventh distillate and a seventh kettle outlet;
the second rectifying unit is connected with the first rectifying unit and is used for rectifying the first kettle output and outputting a second distillate and a second kettle output, the second kettle output returns to the synthetic reaction liquid or returns to the first rectifying unit for rectifying, and the second crystallizing system receives the second distillate for crystallizing and purifying and outputs a second crystallizing liquid and a second mother liquid;
the NVP storage tank is connected with the third rectifying unit and the second crystallizing system and receives the seventh distillate and the second crystallized liquid.
Further, the synthetic reaction liquid is prepared by adopting an acetylene synthesis method, and the synthetic reaction liquid comprises the following components of 30-65% (wt%) of NVP and 35-70% (wt%) of a-p.
Further, the seventh fraction contains purified NVP, wherein the NVP is more than or equal to 99.7 percent (wt%), the a-p is less than or equal to 0.05 percent (wt%), and the PH value is 8.2-9.5.
Further, the second distillate contains purified NVP, wherein the NVP is more than or equal to 99.7 percent (wt%), the a-p is less than or equal to 0.05 percent (wt%), and the PH value is 8.2-9.5.
Further, the second crystallization liquid contains purified NVP, wherein the NVP is more than or equal to 99.9% (wt%), and a-p is less than or equal to 0.05% (wt%).
Compared with the prior art, the utility model has the following beneficial effects:
1) the utility model optimizes and designs the separation and purification process of NVP again, changes semi-continuous rectification into full-continuous rectification operation, improves the utilization efficiency of a rectification system and related crystallization equipment, reduces the retention time of materials in the rectification system from 30-40 hours of the semi-continuous process to 12-18 hours by process optimization, and can obviously improve the production efficiency.
2) The utility model combines the cascade rectification and fractional crystallization, optimizes the rectification operation conditions, and immediately purifies the materials purified by the two-stage rectification and the one-stage crystallization directly by low-temperature rectification (the kettle temperature of the third rectification unit is 110 plus or minus 120 ℃) to distill high-purity NVP, thereby avoiding the continuous staying in the rectification system and repeated high-temperature rectification after the multi-stage rectification and crystallization in the traditional process (the kettle temperature of the rectification tower in the traditional process is 147 +/-3 ℃) and reducing the self-polymerization reaction of the NVP. Thus, the reacted autopolymer decreased from 2.4 tons/day for the conventional process to 1.6 tons/day for the new process.
3) Because N-vinyl pyrrolidine is a heat-sensitive substance, N-vinyl pyrrolidone is easy to generate self-polymerization in the rectification process due to high temperature, the process optimization of the utility model realizes that the retention time of materials in a rectification system is greatly reduced, and the chance of the self-polymerization reaction of the materials is reduced, so that the utility model can improve the yield of NVP, reduce the production cost, reduce the residue rate in NVP production from 30 percent to 22 percent, and improve the yield of NVP by about 8 percent.
4) And (3) performing product crystallization treatment on the second distillate, and further improving the quality (color, purity and the like) of the NVP product of the second distillate to obtain a colorless, transparent and high-purity K90 medical-grade high-quality NVP product.
Drawings
Fig. 1 is a schematic diagram of a NVP purification system and process flow according to embodiment 1;
fig. 2 is a schematic view of an NVP purification system and process flow according to embodiment 2;
FIG. 3 is a schematic diagram of the NVP purification system and process flow according to embodiment 3;
FIG. 4 is a schematic diagram of the NVP purification system and process flow according to embodiment 4;
FIG. 5 is a schematic diagram of the NVP purification system and process flow according to embodiment 5;
FIG. 6 is a schematic diagram of a prior art NVP purification system and process flow.
Reference numerals:
a first rectification unit 1; a second rectification unit 2; a third rectifying column 3; a fourth rectifying column 4; a fifth rectifying column 5; a sixth rectifying column 6; a third rectification unit 7; a first crystallization system 8; a second crystallization system 9; a residue steaming kettle 10; synthesizing a reaction solution 00; the first distillation 11; a first kettle outlet 12; the second distillation 21; a second kettle outlet 22; the third distillation is 31; a third kettle outlet 32; the fourth distillation is 41; a fourth kettle outlet 42; the sixth distillation 61; a sixth kettle outlet 62; the seventh distillation is carried out to obtain 71; a seventh kettle outlet 72; the first crystal liquid 81; a first mother liquor 82; a second crystal liquid 91; a second mother liquor 92; a first rectifying column 1 a; a second rectifying column 1 b; distilling 101 in a first rectifying tower; a first rectification tower kettle outlet 102; a storage tank 1 c; the mixture was distilled off 13.
Detailed Description
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the embodiments will be briefly described below. It is obvious that the drawings in the following description are only some embodiments of the utility model, and that for a person skilled in the art, other drawings can be derived from them without inventive effort.
An aspect of an embodiment of the present invention provides an N-vinylpyrrolidone purification system, including: a first rectification unit 1, a first crystallization system 8 and a third rectification unit 7 which are connected in series in sequence through pipelines, a second rectification unit 2 and a second crystallization system 9 which are connected in series, and an NVP storage tank, wherein,
the first rectification unit 1 receives the synthetic reaction liquid 00 containing NVP for rectification and outputs a first distillate 11 and a first still outlet 12, the first crystallization system 8 receives the first distillate 11 for crystallization and purification and outputs a first crystallization liquid 81 and a first mother liquid 82, and the third rectification unit 7 receives the first crystallization liquid 81 for rectification and outputs a seventh distillate 71 and a seventh still outlet 72;
the second rectification unit 2 is connected to the first rectification unit 1, and outputs a second distillate 21 and a second still outlet 22 after the first still outlet 12 is rectified, the second still outlet 22 returns to the synthetic reaction solution 00 or returns to the first rectification unit 1 for rectification, and the second crystallization system 9 receives the second distillate 21 for crystallization and purification and outputs a second crystallization liquid 91 and a second mother liquid 92;
the NVP storage tank is connected to the third rectification unit 7 and the second crystallization system 9, and receives the seventh distillation fraction 71 and the second crystallization liquid 91.
Further, the synthesis reaction solution 00 is prepared by an acetylene synthesis method, and the synthesis reaction solution 00 comprises 30-65% (wt%) of NVP and 35-70% (wt%) of a-p.
Furthermore, the first distillate 11 contains NVP of more than or equal to 97.8 percent (wt percent) and a-p of less than or equal to 0.15 percent (wt percent).
Further, the NVP in the first kettle outlet 12 accounts for 45-70% (wt%), and a-p accounts for 30-55% (wt%).
Further, the seventh distillation 71 contains purified NVP, wherein the NVP is more than or equal to 99.7% (wt%), the a-p is less than or equal to 0.05% (wt%), and the PH value is 8.2-9.5.
Further, the second distillate 21 contains purified NVP, wherein the NVP is more than or equal to 99.7% (wt%), the a-p is less than or equal to 0.05% (wt%), and the PH value is 8.2-9.5.
Further, the second crystallization liquid contains purified NVP, wherein the NVP is more than or equal to 99.9% (wt%), and a-p is less than or equal to 0.05% (wt%).
Further, the device comprises an incineration device, and the incineration device carries out incineration treatment on the first mother liquor 82, the seventh kettle outlet 72 and the second mother liquor 92.
Further, the second rectification unit 2 includes a fourth rectification tower 4 and a fifth rectification tower 5 connected in sequence, the fourth rectification tower 4 receives the first still outlet 12 of the first rectification unit 1, performs distillation purification, and outputs a fourth distillate 41 and a fourth still outlet 42, the fourth still outlet 42 enters the fifth rectification tower 5, performs distillation purification, and outputs the second distillate 21 and the second still outlet 22, and the fourth distillate 41 enters the first crystallization system 8 for crystallization treatment.
Furthermore, the fourth distillate 41 contains NVP more than or equal to 98 percent (wt%), a-p less than or equal to 0.1 percent (wt%) and a PH value of 10.5-11.5.
Furthermore, the fourth kettle outlet 42 contains NVP more than or equal to 98 percent (wt percent), a-p less than or equal to 1 percent (wt percent) and PH value of 10.2-11.
Further, the second rectification unit 2 further includes a third rectification column 3, the third rectification column 3 is connected in series with the fourth rectification column 4, the third rectification column 3 receives the first still outlet 12 from the first rectification unit 1 and outputs a third distillation fraction 31 and a third still outlet 32, wherein the third distillation fraction 31 enters the fourth rectification column 4, and the third still outlet 32 returns to the synthetic reaction liquid 00 or returns to the first rectification unit 1 for rectification.
Furthermore, the third distillate 31 contains NVP more than or equal to 98 percent (wt percent), a-p less than or equal to 1 percent (wt percent) and a PH value of 10.2-11.
Further, the first rectification unit 1 comprises a first rectification column 1a, a second rectification column 1b, a sixth rectification column 6 and a residue distillation kettle 10, wherein the first rectification column 1a is used for receiving the synthetic reaction liquid 00 and outputting a first rectification column distillate 101 and a first rectification column kettle outlet 102, and the second rectification column 1b is used for receiving the first rectification column distillate 101 and outputting a first distillate 11; the sixth rectifying tower 6 receives the first rectifying tower still outlet 102 and outputs a sixth distillate 61 and a sixth still outlet 62, wherein the sixth still outlet 62 enters the residue steaming still 10, the sixth distillate 61 returns to recover alpha-pyrrolidone, and the sixth distillate 61 comprises NVP (NVP) not less than 90% (wt%), and a-p not more than 10% (wt%).
Further, the distillate 101 of the first rectifying tower consists of NVP accounting for 45-70% (wt%), a-p accounting for 30-55% (wt%), and NVP accounting for 5-10% (wt%) in the material discharged from the bottom 102 of the first rectifying tower; the second rectifying tower 1b outputs the first distillate 11 containing NVP more than or equal to 97.8% (wt%), and a-p less than or equal to 0.15% (wt%).
Further, a storage tank 1c is connected in series between the first rectification unit 1 and the first crystallization system 8, and the storage tank 1c receives the first distillate 11 output from the first rectification unit 1 and outputs a mixed distillate 13 to the first crystallization system 8.
Further, a storage tank 1c is connected in series between the second rectification column 1b and the first crystallization system 8, the storage tank 1c receives the first distillate 11 output from the second rectification column 1b and/or the fourth distillate 41 output from the fourth rectification column 4, and outputs a mixed distillate 13 to the first crystallization system 8, and the mixed distillate 13 has a composition of NVP ≥ 98% (wt%), and a-p ≤ 1.5% (wt%).
Further, the rectifying towers of the first rectifying unit 1, the second rectifying unit 2 and the third rectifying unit 7 are packed towers, and the rectifying operation pressure is 0.082-0.083 MPa.
Further, the temperature of the first distillation column 1a is 140-.
Further, the temperature of the second distillation column 1b is 110-.
Further, the temperature of the third distillation column 3 is 140-.
Further, the temperature of the fourth rectifying tower 4 is 110-120 ℃, and the temperature of the top of the tower is 87-93 ℃.
Further, the temperature of the fifth distillation column 5 is 120-.
Further, the temperature of the sixth rectifying tower 6 is 160-170 ℃, and the temperature of the top of the tower is 145 +/-3 ℃.
Further, the tower temperature of the rectifying tower of the third rectifying unit 7 is 110-.
Further, the residue steaming kettle 10 is a stirring kettle, and the operation pressure is 0.076 MPa.
Further, the operating conditions of the first crystallization system 8 are as follows: the crystallization temperature is-12 ℃ to-6 ℃, the crystallization time is kept for 6 hours at-12 ℃ and kept for 6 hours at-6 ℃.
Further, the operating conditions of the second crystallization system 9 are as follows: the crystallization temperature is 6 ℃ to 11 ℃, and the crystallization time is 4 hours.
Further, the second crystallization system 9 adopts a gradient crystallization method to purify NVP: gradually decreasing the temperature from 11 ℃ to 6 ℃ at 1 ℃/10 min, keeping the temperature at 6 ℃ for 30 min, gradually increasing the temperature to 14 ℃ at 1 ℃/10 min, and keeping the temperature at 14 ℃ for 30 min.
The utility model also provides a method for purifying N-vinyl pyrrolidone by using the N-vinyl pyrrolidone purification system, which comprises the following steps:
s1: the synthetic reaction liquid 00 containing NVP enters a first rectification unit 1 for first-stage NVP purification and outputs a first distillate 11 and a first kettle outlet 12;
s2: the first crystallization system 8 receives the first distillation 11 for secondary NVP purification and outputs a first crystallization liquid 81 and a first mother liquid 82;
s3: the third rectifying unit 7 receives the first crystallized liquid 81 for three-stage NVP purification and outputs a seventh distillate 71 and a seventh kettle outlet 72;
s4: the second rectification unit 2 receives the first still outlet 11 for four-stage NVP purification and outputs a second distillate 21 and a second still outlet 22; the second kettle outlet 22 returns to the synthetic reaction solution 00 or returns to the first rectification unit 1 for rectification treatment;
s5: the second crystallization system 9 receives the second distillation 21, performs five-stage NVP purification, and outputs a second crystallization liquid 91 and a second mother liquid 92;
s6: an NVP storage tank receives the seventh distillation fraction 71 and the second crystal liquid 92.
Further, step S7 is included, in which an incineration device incinerates the first mother liquor 82, the seventh still outlet 72, and the second mother liquor 92.
Further, in step S4, the second rectification unit 2 includes a fourth rectification column 4 and a fifth rectification column 5 connected in sequence, the fourth rectification column 4 receives the first still outlet 12 of the first rectification unit 1, performs distillation and purification, and outputs a fourth distillate 41 and a fourth still outlet 42, the fourth still outlet 42 enters the fifth rectification column 5, performs distillation and purification, and outputs the second distillate 21 and the second still outlet 22, and the fourth distillate 41 enters the first crystallization system 8 for crystallization.
Further, the synthesis reaction solution 00 is prepared by an acetylene synthesis method, and the synthesis reaction solution 00 comprises 30-65% (wt%) of NVP and 35-70% (wt%) of a-p.
Furthermore, the first distillate 11 contains NVP of more than or equal to 97.8 percent (wt percent) and a-p of less than or equal to 0.15 percent (wt percent).
Further, the NVP in the first kettle outlet 12 accounts for 45-70% (wt%), and a-p accounts for 30-55% (wt%).
Further, the seventh distillation 71 contains purified NVP, wherein the NVP is more than or equal to 99.7% (wt%), the a-p is less than or equal to 0.05% (wt%), and the PH value is 8.2-9.5.
Further, the second distillate 21 contains purified NVP, wherein the NVP is more than or equal to 99.7% (wt%), the a-p is less than or equal to 0.05% (wt%), and the PH value is 8.2-9.5.
Furthermore, the fourth distillate 41 contains NVP more than or equal to 98 percent (wt%), a-p less than or equal to 0.1 percent (wt%) and a PH value of 10.5-11.5.
Furthermore, the fourth kettle outlet 42 contains NVP more than or equal to 98 percent (wt percent), a-p less than or equal to 1 percent (wt percent) and PH value of 10.2-11.
Further, the second crystallization liquid 91 contains purified NVP, wherein NVP is more than or equal to 99.9% (wt%), and a-p is less than or equal to 0.05% (wt%).
Further, in step S4, the second rectification unit 2 further includes a third rectification column 3, the third rectification column 3 is connected in series with the fourth rectification column 4, the third rectification column 3 receives the first still output 12 from the first rectification unit 1 and outputs a third distillation output 31 and a third still output 32, where the third distillation output 31 enters the fourth rectification column 4, and the third still output 32 returns to the synthesis reaction liquid 00 or returns to the first rectification unit 1 for rectification processing.
Furthermore, the third distillate 31 contains NVP more than or equal to 98 percent (wt percent), a-p less than or equal to 1 percent (wt percent) and a PH value of 10.2-11.
Further, in step S1, the first rectification unit 1 includes a first rectification column 1a, a second rectification column 1b, a sixth rectification column 6 and a residue distillation kettle 10, the first rectification column 1a is used for receiving the synthesis reaction liquid 00 and outputting a first rectification column distillate 101 and a first rectification column kettle outlet 102, and the second rectification column 1b receives the first rectification column distillate 101 and outputs the first distillation 11; the sixth rectifying tower 6 receives the first rectifying tower still outlet 102 and outputs a sixth distillate 61 and a sixth still outlet 62, wherein the sixth still outlet 62 enters the residue steaming still 10, the sixth distillate 61 returns to recover alpha-pyrrolidone, and the sixth distillate 61 comprises NVP (NVP) not less than 90% (wt%), and a-p not more than 10% (wt%).
Further, the distillate 101 of the first rectifying tower consists of NVP accounting for 45-70% (wt%), a-p accounting for 30-55% (wt%), and NVP accounting for 5-10% (wt%) in the material discharged from the bottom 102 of the first rectifying tower; the second rectifying tower 1b outputs the first distillate 11 containing NVP more than or equal to 97.8% (wt%), and a-p less than or equal to 0.15% (wt%).
Further, a storage tank 1c is connected in series between the first rectification unit 1 and the first crystallization system 8, and the storage tank 1c receives the first distillate 11 output from the first rectification unit 1 and outputs a mixed distillate 13 to the first crystallization system 8.
Further, a storage tank 1c is connected in series between the second rectification column 1b and the first crystallization system 8, the storage tank 1c receives the first distillate 11 output from the second rectification column 1b and/or the fourth distillate 41 output from the fourth rectification column 4, and outputs a mixed distillate 13 to the first crystallization system 8, and the mixed distillate 13 has a composition of NVP ≥ 98% (wt%), and a-p ≤ 1.5% (wt%).
Further, the rectifying towers of the first rectifying unit 1, the second rectifying unit 2 and the third rectifying unit 7 are packed towers, and the rectifying operation pressure is 0.082-0.083 MPa.
Further, the temperature of the first distillation column 1a is 140-.
Further, the temperature of the second distillation column 1b is 110-.
Further, the temperature of the third distillation column 3 is 140-.
Further, the temperature of the fourth rectifying tower 4 is 110-120 ℃, and the temperature of the top of the tower is 87-93 ℃.
Further, the temperature of the fifth distillation column 5 is 120-.
Further, the temperature of the sixth rectifying tower 6 is 160-170 ℃, and the temperature of the top of the tower is 145 +/-3 ℃.
Further, the tower temperature of the rectifying tower of the third rectifying unit 7 is 110-.
Further, the residue steaming kettle 10 is a stirring kettle, and the operation pressure is 0.076 MPa.
Further, the operating conditions of the first crystallization system 8 are as follows: the crystallization temperature is-12 ℃ to-6 ℃, the crystallization time is kept for 6 hours at-12 ℃ and kept for 6 hours at-6 ℃.
Further, the operating conditions of the second crystallization system 9 are as follows: the crystallization temperature is 6 ℃ to 11 ℃, and the crystallization time is 4 hours.
Further, the second crystallization system 9 adopts a gradient crystallization method to purify NVP: adding seed crystal at 11 deg.c in 0.1 wt% of the crystallization liquid, gradually lowering the temperature from 11 deg.c to 6 deg.c at 1 deg.c/10 min, maintaining at 6 deg.c for 30 min, raising the temperature to 14 deg.c at 1 deg.c/10 min, and maintaining at 14 deg.c for 30 min. The present invention is described in detail below with reference to the drawings and the specific embodiments, which are not repeated herein, but the embodiments of the present invention are not limited to the following embodiments.
Fig. 1 is a schematic view of an NVP refining system and process flow according to embodiment 1 of the present invention.
As shown in fig. 1, an N-vinyl pyrrolidone refining system includes: a first rectification unit 1, a first crystallization system 8 and a third rectification unit 7 which are connected in series in sequence through pipelines, a second rectification unit 2 and a second crystallization system 9 which are connected in series, and an NVP storage tank. The first rectification unit 1 receives the synthetic reaction liquid 00 containing NVP, carries out rectification treatment and outputs a first distillate 11 and a first kettle outlet 12, the first crystallization system 8 receives the first distillate 11, carries out crystallization purification and outputs a first crystallization liquid 81 and a first mother liquid 82, and the third rectification unit 7 receives the first crystallization liquid 81, carries out rectification treatment and outputs a seventh distillate 71 and a seventh kettle outlet 72; the second rectification unit 2 is connected with the first rectification unit 1, rectifies the first kettle outlet 12 and outputs a second distillate 21 and a second kettle outlet 22, and the second kettle outlet 22 returns to the synthetic reaction liquid 00 or returns to the first rectification unit 1 for rectification; the second crystallization system 9 receives the second distillate 21 for crystallization and purification and outputs a second crystallization liquid 91 and a second mother liquid 92; the NVP storage tank is connected to the third rectifying unit 7 and the second crystallizing system 9, and receives the seventh distillate 71 and the second crystallized liquid 91. The first rectifying unit 1, the second rectifying unit 2 and the third rectifying unit 7 are all packed towers.
As shown in fig. 1, a synthetic reaction solution 00 of NVP is prepared by an acetylene synthesis method, after gas-liquid separation, the synthetic reaction solution 00 comprises NVP 30-65% (wt%), a-p 35-70% (wt%), the synthetic reaction solution 00 enters a first rectification unit 1 at 960 liters/hour for first-stage NVP purification (i.e., first-stage rectification purification), a first distillation 11 is extracted from the top of the rectification unit at a rectification operation pressure of 0.082-0.083MPa and a rectification tower top temperature of 100 and 106 ℃, wherein the first distillation 11 comprises NVP more than or equal to 97.8% (wt%), a-p less than or equal to 0.15% (wt%), and a first distillation 12 is extracted from the bottom of the rectification tower of the first rectification unit 1, wherein the NVP 45-70% (wt%) and the a-p 30-55% (wt%).
The first distillate 11 after NVP purification enters the first crystallization system 8 for second-stage NVP purification (i.e. first-stage crystallization purification), and the operation conditions of the first crystallization system 8 are as follows: the crystallization temperature is-12 ℃ to-6 ℃, the crystallization time is kept for 6 hours at-12 ℃ and kept for 6 hours at-6 ℃. Crystallizing and purifying to obtain a first crystal liquid 81 and a first mother liquid 82, sending the first mother liquid 82 to an incineration device for incineration treatment, sending the first crystal liquid 81 subjected to NVP recovery through the first crystallization system 8 to the third rectification unit 7 for three-stage NVP purification (namely, two-stage rectification purification) and outputting a seventh distillate 71, and outputting a seventh kettle 72 from the third rectification unit 7 for incineration treatment.
In this embodiment, the rectifying tower of the third rectifying unit 7 controls the tower still temperature to be 110-: NVP is more than or equal to 99.7 percent (wt%), a-p is less than or equal to 0.05 percent (wt%), and the PH value is 8.2-9.5, and the purified NVP is used as a product to enter an NVP product storage tank.
As shown in fig. 1, the first still outlet 12 of the first rectification unit 1 enters the second rectification unit 2, and the first still outlet 12 containing NVP is subjected to four-stage NVP purification (i.e., three-stage rectification purification) to separate NVP and a-p. Under the rectification operating pressure of 0.082-0.083MPa, and when the tower top temperature is controlled to be 100-106 ℃, a second distillation 21 is extracted from the tower top of the rectification tower of the second rectification unit 2, and the NVP contained in the second distillation 21 after purification reaches the product receiving standard, namely: NVP is more than or equal to 99.7 percent (wt%), a-p is less than or equal to 0.05 percent (wt%), and the PH value is 8.2-9.5, and the purified NVP is used as a raw material and enters a second crystallization system 9 to carry out five-stage NVP purification (namely, secondary crystallization purification) to obtain a second crystallization liquid 91 and a second mother liquid 92. The second kettle outlet 22 output by the second rectification unit 2 returns to the synthetic reaction liquid 00 or returns to the first rectification unit 1 for rectification. The second mother liquor 92 is sent to an incineration device for treatment.
In the present embodiment, the operating conditions of the second crystallization system 9 are: the crystallization temperature is 6 ℃ to 14 ℃ and the crystallization time is 4 hours. The specific operation is that the second crystallization system 9 adopts a gradient crystallization method to purify NVP: adding seed crystal (accounting for 0.1% of the crystallization stock solution by mass) at 11 deg.C, gradually decreasing from 11 deg.C to 6 deg.C at 1 deg.C/10 min, maintaining at 6 deg.C for 30 min, gradually increasing to 14 deg.C at 1 deg.C/10 min, and maintaining at 14 deg.C for 30 min. Separating the mother liquor from the crystallization liquid. The second crystallization system 9 is arranged to further purify the quality of the NVP product, and the second crystallization liquid 91 after crystallization and purification by the gradient crystallization method of the second crystallization system 9 is colorless and transparent, wherein the NVP is more than or equal to 99.9 percent (wt percent), and a-p is less than or equal to 0.05 percent (wt percent), and is a qualified high-purity NVP product, the quality of the crystallized NVP can be further improved, and the prepared NVP monomer can be used for preparing medicinal PVP.
In the embodiment, the synthetic reaction solution 00 of NVP is prepared by an acetylene synthesis method, the NVP accounts for 30-65% (wt%) and the a-p accounts for 35-70% (wt%) in the composition of the synthetic reaction solution 00 after gas-liquid separation, and a purified NVP product with the NVP more than or equal to 99.7% (wt%), the a-p less than or equal to 0.05% (wt%) and the PH value of 8.2-9.5 can be obtained through three-stage rectification and one-stage crystallization treatment, and a high-purity medical-grade NVP product with the NVP more than or equal to 99.9% (wt%) and the a-p less than or equal to 0.05% (wt%) can also be obtained through two-stage crystallization treatment.
In the embodiment, because the NVP synthesis reaction solution 00 is purified and separated by first-stage rectification to form two materials which are respectively refined in parallel, namely, the synthetic reaction solution 00 is firstly subjected to first-stage purification by a first rectification unit 1 to form a first distillate 11, then is subjected to first-stage crystallization purification to form a crystallization solution, the qualified NVP product is directly separated from the crystallization liquid under the mild second-stage rectification operation condition, the kettle outlet separated by the first rectification unit 1 is purified and separated by parallel third-stage rectification, and then second-stage crystallization and purification are carried out to form the crystallization liquid to produce high-purity medical-grade NVP, because the first-stage crystallization liquid is not returned to the third-stage rectification, the retention time of the NVP, especially the high-concentration NVP material after crystallization and purification, in a rectification system when the NVP material is treated by the traditional process is shortened, therefore, the reaction of self-polymerization of NVP is greatly reduced, and the yield of NVP is obviously improved. At 960 liters/hour of the synthetic reaction solution 00 feed, the reacted autopolymer was 2.0 tons/day, and the residue rate was 28%. By adopting the embodiment, NVP products used in K30 industrial grade and K90 pharmaceutical grade can be obtained.
Fig. 2 is a schematic diagram of the NVP purification system and process flow according to embodiment 2. The synthetic reaction liquid 00 of NVP is prepared by adopting an acetylene synthesis method, the NVP accounts for 30-55% (wt%) and the a-p accounts for 45-70% (wt%) in the composition of the synthetic reaction liquid 00 after gas-liquid separation, and the synthetic reaction liquid 00 enters the first rectification unit 1 at 960 liters/hour for first-stage NVP purification (namely first-stage rectification purification). The difference from embodiment 1 is mainly as follows:
as shown in fig. 2, the second rectification unit 2 of the NVP refining system includes two packed towers, namely a fourth rectification tower 4 and a fifth rectification tower 5, connected in sequence, the fourth rectification tower 4 receives the first still outlet 12 of the first rectification unit 1, performs distillation purification, and outputs a fourth distillate 41 and a fourth still outlet 42, the fourth still outlet 42 enters the fifth rectification tower 5, performs distillation purification, and outputs a second distillate 21 and a second still outlet 22, and the fourth distillate 41 enters the first crystallization system 8 for crystallization treatment.
In the embodiment, as shown in fig. 2, the first outlet 12 containing NVP is subjected to two-step purification treatment in the second distillation unit 2, i.e., four-stage and five-stage NVP purification (i.e., three-stage and four-stage distillation purification), the column temperature of the fourth distillation column 4 is controlled to be 110-. Wherein 40L of fourth distillate 41 is obtained about every 3 hours by controlling the fourth rectifying tower 4, wherein the fourth distillate comprises NVP which is more than or equal to 98 percent (wt percent), a-p which is less than or equal to 0.1 percent (wt percent) and has a pH value of 10.5-11.5, and the fourth still outlet 42 comprises NVP which is more than or equal to 98 percent (wt percent), a-p which is less than or equal to 1 percent (wt percent) and has a pH value of 10.2-11. The fourth distillate 41 enters a first crystallization system 8 for crystallization treatment, and the fourth kettle outlet 42 enters a fifth rectifying tower 5 for distillation and purification and outputs a second distillate 21 and a second kettle outlet 22. The flow rate of the second distillation 21 extracted from the top of the fifth distillation column 5 is 340-350L/h, and the flow rate from the bottom of the column is 70-80L/h.
Because the material 00 of the synthetic reaction liquid of NVP contains light components such as polyamine substances or pyridine substances with boiling points close to that of NVP, the light components are difficult to remove through first-stage rectification and purification, and the existence of the light components can cause yellowing of final NVP products, in the embodiment, a fourth rectifying tower 4 and a fifth rectifying tower 5 are set up, and the lower tower bottom temperature and tower top temperature of the fourth rectifying tower 4 relative to the fifth rectifying tower 5 are controlled, the light components and NVP can be separated under relatively mild rectification operating conditions of the fourth rectifying tower 4, the light components and NVP are separated, the NVP accounts for 45-70% (wt%) and the a-p accounts for 30-55% (wt%) of a first tower outlet 12, the NVP accounts for more than or equal to 98% (wt%) and the a-p accounts for less than or equal to 0.1% (wt%) of a crude NVP products are separated through the fourth rectifying tower 4 under the rectification operating conditions, 40L of flow rate is collected every 3 hours and then enters a first crystallization system 8, qualified NVP products can be further purified, the self-polymerization reaction occurrence probability of the NVP can be reduced, and the yield of the NVP is obviously improved. Under the condition that the feeding of the synthetic reaction liquid 00 is 960 liters/hour, the reacted autopolymer is 1.8 tons/day, and the residue rate of NVP production is 24 percent. By adopting the embodiment, the yield of NVP product used by K90 pharmaceutical grade can be improved.
Fig. 3 is a schematic diagram of the NVP purification system and process flow according to embodiment 3. The synthetic reaction liquid 00 of NVP is prepared by adopting an acetylene synthesis method, the NVP accounts for 30-65% (wt%) and the a-p accounts for 35-70% (wt%) in the composition of the synthetic reaction liquid 00 after gas-liquid separation, and the synthetic reaction liquid 00 enters the first rectification unit 1 at 960 liters/hour for first-stage NVP purification (namely first-stage rectification purification). The difference from embodiment 2 is mainly as follows:
as shown in fig. 3, the second rectification unit 2 of the NVP refining system further includes a third rectification column 3, the third rectification column 3 is disposed at the front end of the fourth rectification column 4 and is connected in series with the fourth rectification column 4, the third rectification column 3 receives the first still output 12 from the first rectification unit 1 and outputs a third distillation output 31 and a third still output 32, wherein the third distillation output 31 enters the fourth rectification column 4, and the third still output 32 returns to the synthetic reaction liquid 00 or returns to the first rectification unit 1 for rectification.
In the embodiment, the third distillation column 3 is a packed column, under the conditions that the distillation operation pressure is 0.082-0.083MPa, the column bottom temperature is 140-, the first kettle outlet 12 from the first rectifying unit 1 is rectified, the third rectifying tower 3 is arranged to deeply rectify and refine the kettle outlet material purified by first-stage rectification at a higher temperature to produce NVP products as much as possible, the material amount returned to the first rectifying unit 1 for rectification is reduced, the repeated rectification and long-time retention time of the material in a rectifying system is shortened, the self-polymerization of the NVP is reduced, and the yield of the NVP target product is improved. In the present embodiment, the third fraction 31 contains NVP of 98% or more (wt%), a-p of 1% or less (wt%), and has a pH of 10.2 to 11. Under the condition that the feeding amount of the synthetic reaction liquid 00 is 960 liters/hour, the reacted autopolymer is 1.6 tons/day, the residue rate of NVP production is 22 percent, and the residue rate is further reduced.
Fig. 4 is a schematic diagram of the NVP purification system and process flow according to embodiment 4. The synthetic reaction liquid 00 of NVP is prepared by adopting an acetylene synthesis method, the NVP accounts for 30-65% (wt%) and the a-p accounts for 35-70% (wt%) in the composition of the synthetic reaction liquid 00 after gas-liquid separation, and the synthetic reaction liquid 00 enters the first rectification unit 1 at 960 liters/hour for first-stage NVP purification (namely first-stage rectification purification). The difference from embodiment 3 is mainly as follows:
as shown in fig. 4, the first rectifying unit 1 of the NVP refining system includes a first rectifying tower 1a, a second rectifying tower 1b, a sixth rectifying tower 6 and a residue distillation kettle 10, the first rectifying tower 1a is configured to receive the NVP synthesis reaction liquid 00 and output a first rectifying tower distillate 101 and a first rectifying tower kettle outlet 102, and the second rectifying tower 1b is configured to receive the first rectifying tower distillate 101 and output a first distillate 11 and a first kettle outlet 12; the sixth rectifying tower 6 receives the first rectifying tower still outlet 102 and outputs a sixth distillate 61 and a sixth still outlet 62, wherein the sixth still outlet 62 enters the residue distilling still 10, the sixth distillate 61 returns to recover alpha-pyrrolidone, and the sixth distillate 61 comprises NVP (n v p) of not less than 90% (wt%), and a-p of not more than 10% (wt%).
In the embodiment, the first rectifying tower 1a is a packed tower, and is used as a rough distillation tower for rectifying and purifying NVP, under the conditions that the rectifying operation pressure is 0.082-0.083MPa, the tower kettle temperature is 140-.
In the embodiment, the second rectifying tower 1b is a packed tower, and is used as a light component removing tower for rectifying and purifying NVP to remove light components such as polyamine substances or pyridine substances with a boiling point close to that of NVP brought by the NVP synthesis reaction solution 00 material in the NVP crude product, under the conditions that the distillation operation pressure is 0.082-0.083MPa, the tower temperature of the second distillation tower 1b is 110-, rectifying the material 101 distilled from the first rectifying tower and outputting the material 11 distilled from the first rectifying tower, wherein the NVP content is more than or equal to 97.8 percent (wt percent), and a-p content is less than or equal to 0.15 percent (wt percent), due to the arrangement of the second rectifying tower 1b, the yellowing phenomenon of the NVP product is obviously improved, and the quality of the NVP product is obviously improved.
As shown in fig. 4, in the present embodiment, the sixth rectification column 6 is a packed column, and is configured to recover the α -pyrrolidone in the NVP synthesis reaction liquid 00 material. Under the conditions that the distillation operation pressure is 0.082-0.083MPa, the temperature of a tower kettle is 160-. The slag steaming kettle 10 is a stirring kettle, the capacity is 100-110L, and the operating pressure is 0.076 MPa.
In the present embodiment, the first rectification unit 1 is provided with a two-stage rectification tower to perform rectification and purification on the synthetic reaction liquid 00 containing NVP, remove light components, and is provided with a sixth rectification tower 6 to perform rectification on the first rectification tower bottom 102 and recover alpha-pyrrolidone in a matching manner, so that purification of NVP can be achieved, and alpha-pyrrolidone can be recovered at the same time, thereby reducing the cost of production operation. Under the condition that the feeding of the synthetic reaction liquid 00 is 960 liters/hour, the reacted autopolymer is 1.6 tons/day, and the residue rate of NVP production is 22 percent.
Fig. 5 is a schematic diagram of the NVP purification system and process flow according to embodiment 5. The synthetic reaction liquid 00 of NVP is prepared by adopting an acetylene synthesis method, the NVP accounts for 30-65% (wt%) and the a-p accounts for 35-70% (wt%) in the composition of the synthetic reaction liquid 00 after gas-liquid separation, and the synthetic reaction liquid 00 enters the first rectification unit 1 at 960 liters/hour for first-stage NVP purification (namely first-stage rectification purification). The difference from embodiment 4 is mainly as follows:
as shown in fig. 5, a storage tank 1c is connected in series between the first rectifying unit 1 and the first crystallizing system 8 of the NVP refining system, the storage tank 1c receives the first distillate 11 output from the second rectifying tower 1b of the first rectifying unit 1 and the fourth distillate 41 output from the fourth rectifying tower of the second rectifying unit 2, and outputs a mixed distillate 13 to the first crystallizing system 8, and the mixed distillate 13 has a composition of NVP ≥ 98% (wt%), and a-p ≤ 1.5% (wt%).
In the present embodiment, one storage tank 1c is provided in series upstream of the first crystallization system 8. On one hand, the storage tank 1c provides material guarantee for the downstream first crystallization system 8, because the rectification operation in the NVP refining system continuously operates, the first crystallization system 8 is gradient crystallization and intermittent operation, if the first distillate 11 and/or the fourth distillate 41 directly enters the first crystallization system 8, the stable operation of the whole NVP refining system and process is disturbed, and the quality of the final NVP product is affected, on the other hand, the storage tank 1c is used for receiving the two rectification fractions of the first rectification unit 1 and the second rectification unit 2, fully mixing the NVP rectification and playing a material buffering role, so as to better guarantee the stable operation of the crystallization system. Under the condition that the feeding of the synthetic reaction liquid 00 is 960 liters/hour, the reacted autopolymer is 1.6 tons/day, and the residue rate of NVP production is 22 percent.
FIG. 6 is a schematic diagram of a prior art NVP purification system and process flow. The synthetic reaction liquid of NVP is prepared by adopting an acetylene synthesis method, the NVP accounts for 30-55% (wt%) and the a-p accounts for 45-70% (wt%) in the composition of the synthetic reaction liquid after gas-liquid separation, and the synthetic reaction liquid enters a first rectifying tower at 960 liters/hour for first-stage rectification and purification.
As shown in fig. 6, the NVP purification system of the prior art includes a first rectifying tower, a second rectifying tower, a storage tank, a crystallization system, a third rectifying tower and a fourth rectifying tower connected in series with the second rectifying tower, and a fifth rectifying tower and a residue steaming kettle connected in series with the first rectifying tower. In the embodiment, all the rectifying towers are packed towers, and the rectifying operation pressure is 0.082-0.083 MPa.
As shown in fig. 6, a synthetic reaction solution of NVP is prepared by an acetylene synthesis method, the synthetic reaction solution after gas-liquid separation contains 30-65% (wt%) of NVP and 35-70% (wt%) of a-p, and the synthetic reaction solution enters a first rectifying tower to be subjected to first-stage rectification and purification to obtain a first rectifying tower distillate and a first rectifying tower still outlet, wherein the first rectifying tower distillate enters a second rectifying tower to be subjected to second-stage rectification and purification to obtain a second rectifying tower distillate and a second rectifying tower still outlet, the second rectifying tower distillate enters a storage tank, a crystallization system receives a first fraction in the storage tank to be subjected to crystallization and purification to obtain a crystallization liquid and a mother liquid, and the crystallization liquid is sent to the second rectifying tower to be subjected to continuous rectification. And the third rectifying tower receives the continuous rectification and purification from the second rectifying tower and outputs the distillate of the third rectifying tower, and the intermittent rectification and purification are continuously carried out in the fourth rectifying tower until the qualified NVP product is distilled from the tower top.
In this embodiment, the residue from the first distillation column enters a fifth distillation column for distillation and purification to form a distillate from the fifth distillation column and a residue from the first distillation column, wherein the residue from the first distillation column is sent to a residue distillation column for treatment, and the distillate is used for recovering alpha-pyrrolidone.
In the present embodiment:
the first rectifying tower is a packed tower, under the conditions that the rectifying operation pressure is 0.082-0.083MPa, the tower kettle temperature is 140-150 ℃, the tower top temperature is 124-130 ℃ and the material rectifying residence time is 2-3 hours, the NVP synthetic reaction liquid is subjected to primary purification and rectification, and the distillate of the first rectifying tower extracted from the top of the first rectifying tower comprises 45-70 percent (wt%) of NVP, 30-55 percent (wt%) of a-p and 5-10 percent (wt%) of NVP in the material 102 from the bottom of the first rectifying tower.
The second rectifying tower is a packed tower, under the conditions that the rectifying operation pressure is 0.082-0.083MPa, the kettle temperature of the second rectifying tower is 110-120 ℃, the tower top temperature is 100-106 ℃ and the material rectifying residence time is 2-3 hours, the distillation material of the first rectifying tower is rectified and output to the second rectifying tower, wherein the distillation material contains NVP more than or equal to 97.8 percent (wt percent) and a-p less than or equal to 0.15 percent (wt percent).
The third rectifying tower is a packed tower, under the conditions that the rectifying operation pressure is 0.082-0.083MPa, the tower kettle temperature is 140-150 ℃, the tower top temperature is 100-106 ℃ and the material rectifying residence time is 2-3 hours, the third rectifying tower which is used for rectifying the material from the second rectifying tower kettle and outputs the distillate containing NVP more than or equal to 98 percent (wt percent), a-p less than or equal to 1 percent (wt percent) and the PH value is 10.2-11.
The fourth rectifying tower is a packed tower, under the conditions that the rectifying operation pressure is 0.082-0.083MPa, the tower kettle temperature is 120-130 ℃ and the tower top temperature is 100-106 ℃, the distillate from the third rectifying tower is rectified and output to the fourth rectifying tower, and in order to ensure that the NVP in the distillate is more than or equal to 99.7 percent (wt percent), the a-p is less than or equal to 0.05 percent (wt percent) and the PH value is 8.2-9.5, the qualified requirement of the NVP product is met, the material rectifying residence time is required to be controlled to be 24-30 hours.
And the fifth rectifying tower is a packed tower, under the conditions that the rectifying operation pressure is 0.082-0.083MPa, the tower kettle temperature is 160-170 ℃, the tower top temperature is 145 +/-3 ℃ and the material rectifying residence time is 2-3 hours, purifying the kettle outlet of the first rectifying tower and outputting the distillate and the kettle outlet of the fifth rectifying tower, wherein the kettle outlet enters a residue distillation kettle for treatment, the distillate returns to recover alpha-pyrrolidone, and the distillate component is NVP (nitrogen to noise ratio) which is more than or equal to 90 percent (wt percent) and a-p (alpha-p) which is less than or equal to 10 percent (wt percent). The residue steaming kettle is a stirring kettle, and the operation pressure is 0.076 MPa.
In the embodiment, semi-continuous separation is adopted in the rectification separation process of the synthetic reaction liquid containing NVP, intermittent distillation is adopted in the last step (fourth rectification tower) to ensure that the NVP product with qualified purity is produced, the residence time of the step is about 24-30 hours, the rectification treatment time of the previous three towers is 6-9 hours, the residence time of the material in the rectification tower is up to 30-40 hours, due to the fact that the heat-sensitive substances in the N-vinyl pyrrolidone are in the rectification process, particularly under the high-temperature environment of the third rectification tower, a large amount of N-vinyl pyrrolidone is subjected to self-polymerization, the material self-polymerization is 2.4 tons/day, and the NVP production residue rate is up to 30%.
The above description is only one embodiment of the present invention, and is not intended to limit the present invention, and it is apparent to those skilled in the art that various modifications and variations can be made in the present invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (10)
1. An N-vinyl pyrrolidone purification system, comprising: a first rectifying unit, a first crystallizing system and a third rectifying unit which are connected in series in turn through pipelines, a second rectifying unit and a second crystallizing system which are connected in series, and an NVP storage tank, wherein,
the first rectifying unit receives a synthetic reaction liquid containing NVP (N-vinyl pyrrolidone) for rectifying and outputs a first distillate and a first kettle outlet, the first crystallization system receives the first distillate for crystallization and purification and outputs a first crystallization liquid and a first mother liquid, and the third rectifying unit receives the first crystallization liquid for rectifying and outputs a seventh distillate and a seventh kettle outlet;
the second rectifying unit is connected with the first rectifying unit and is used for rectifying the first kettle output and outputting a second distillate and a second kettle output, the second kettle output returns to the synthetic reaction liquid or returns to the first rectifying unit for rectifying, and the second crystallizing system receives the second distillate for crystallizing and purifying and outputs a second crystallizing liquid and a second mother liquid;
the NVP storage tank is connected with the third rectifying unit and the second crystallizing system and receives the seventh distillate and the second crystallized liquid.
2. The N-vinylpyrrolidone purification system of claim 1,
the seventh fraction contains purified NVP, wherein the NVP is more than or equal to 99.7 percent (wt%), the a-p is less than or equal to 0.05 percent (wt%), and the PH value is 8.2-9.5.
The second distillate contains purified NVP, wherein the NVP is more than or equal to 99.7 percent (wt%), the a-p is less than or equal to 0.05 percent (wt%), and the PH value is 8.2-9.5.
The second crystallization liquid contains purified NVP, wherein the NVP is more than or equal to 99.9 percent (wt percent), and a-p is less than or equal to 0.05 percent (wt percent).
3. A purification system of N-vinylpyrrolidone as claimed in claim 1, wherein the synthesis reaction liquid is prepared by acetylene synthesis and has a composition of NVP 30 to 65% (wt%) and a-p 35 to 70% (wt%).
4. The N-vinyl pyrrolidone purification system of claim 1, wherein the second rectification unit comprises a fourth rectification column and a fifth rectification column which are connected in sequence, the fourth rectification column receives the first still outlet of the first rectification unit, performs distillation purification, and outputs a fourth distillate and a fourth still outlet, the fourth still outlet enters the fifth rectification column for distillation purification and outputs the second distillate and the second still outlet, and the fourth distillate enters the first crystallization system for crystallization treatment.
5. The purification system of N-vinyl pyrrolidone as claimed in claim 4, wherein the fourth distillation contains NVP more than or equal to 98% (wt%), a-p less than or equal to 0.1% (wt%), and pH value is 10.5-11.5; the fourth kettle outlet contains NVP more than or equal to 98 percent (wt percent), a-p less than or equal to 1 percent (wt percent) and PH value of 10.2-11.
6. The N-vinylpyrrolidone purification system of claim 4 or 5, wherein the second rectification unit further comprises a third rectification column connected in series with the fourth rectification column, the third rectification column receives the first still output from the first rectification unit and outputs a third distillation and a third still output, wherein the third distillation enters the fourth rectification column, and the third still output is returned to the synthesis reaction liquid or the first rectification unit for rectification.
7. The N-vinylpyrrolidone purification system of claim 6 further comprising a storage tank connected in series between the first rectification unit and the first crystallization system, the storage tank receiving the first distillate from the output of the first rectification unit and outputting a mixed distillate to the first crystallization system.
8. The purification system of any one of claims 1-5, wherein the first rectification unit comprises a first rectification column, a second rectification column, a sixth rectification column and a residue distillation kettle, the first rectification column is used for receiving the synthesis reaction liquid and outputting a first rectification column distillate and a first rectification column kettle outlet, and the second rectification column is used for receiving the first rectification column distillate and outputting the first distillate; and the sixth rectifying tower receives the first rectifying tower kettle output and outputs a sixth distillate and a sixth kettle output, wherein the sixth kettle output enters the residue distilling kettle, the sixth distillate returns to recover alpha-pyrrolidone, and the composition of the sixth distillate is that NVP is more than or equal to 90% (wt%), and a-p is less than or equal to 10% (wt%).
9. The purification system of any one of claims 1-5, further comprising an incineration device, wherein the incineration device incinerates the first mother liquor, the seventh still outlet, and the second mother liquor.
10. A purification system according to any one of claims 1 to 5, wherein the first crystallization system is operated under the following conditions: the crystallization temperature is-12 ℃ to-6 ℃, the crystallization time is kept for 6 hours at-12 ℃ and kept for 6 hours at-6 ℃;
the operating conditions of the second crystallization system are as follows: the crystallization temperature is 6 ℃ to 11 ℃, and the crystallization time is 4 hours;
and the second crystallization system adopts a gradient crystallization method to purify NVP: adding seed crystal at 11 deg.c in 0.1 wt% of the crystallization liquid, gradually lowering the temperature from 11 deg.c to 6 deg.c at 1 deg.c/10 min, maintaining at 6 deg.c for 30 min, raising the temperature to 14 deg.c at 1 deg.c/10 min, and maintaining at 14 deg.c for 30 min.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202121467485.7U CN215822383U (en) | 2021-07-03 | 2021-07-03 | N-vinyl pyrrolidone purification system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202121467485.7U CN215822383U (en) | 2021-07-03 | 2021-07-03 | N-vinyl pyrrolidone purification system |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN215822383U true CN215822383U (en) | 2022-02-15 |
Family
ID=80190944
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202121467485.7U Active CN215822383U (en) | 2021-07-03 | 2021-07-03 | N-vinyl pyrrolidone purification system |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN215822383U (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113476877A (en) * | 2021-07-03 | 2021-10-08 | 乌兰察布市珂玛新材料有限公司 | N-vinyl pyrrolidone purification system and method |
-
2021
- 2021-07-03 CN CN202121467485.7U patent/CN215822383U/en active Active
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113476877A (en) * | 2021-07-03 | 2021-10-08 | 乌兰察布市珂玛新材料有限公司 | N-vinyl pyrrolidone purification system and method |
| CN113476877B (en) * | 2021-07-03 | 2024-04-19 | 乌兰察布市珂玛新材料有限公司 | N-vinyl pyrrolidone purification system and method |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN101027276B (en) | Method for the continuous production of alkyl amino acryl amides | |
| CN113582845B (en) | Device and process for co-producing electronic grade methyl ethyl carbonate and diethyl carbonate by reaction rectification method | |
| CN215822383U (en) | N-vinyl pyrrolidone purification system | |
| KR19990076763A (en) | Method for preparing gamma-butyrolactone and uses thereof | |
| KR20110011917A (en) | Process for preparing of n-methyl pyrrolidone | |
| CN106588590A (en) | Refinement method for polyoxymethylene dimethyl ether | |
| TWI418542B (en) | Process for preparation of n-methyl pyrrolidone | |
| CN111217684A (en) | Production method for improving yield of cyclohexanone | |
| CN108191743B (en) | Method for realizing 2-methylpyridine dehydration by side-line extraction of azeotropic distillation tower | |
| KR20040063970A (en) | Process for recovering caprolactam | |
| CN113476877A (en) | N-vinyl pyrrolidone purification system and method | |
| CN111018757B (en) | Method for synthesizing 3-mercaptopropionic acid from acidic waste gas | |
| KR100727504B1 (en) | Process for the Production of N-Methyl Pyrrolidone Using Gamma Butyrolactone and Mixed Methylamines as Starting Materials | |
| CN116283704A (en) | Continuous preparation method of N-methylpyrrolidone | |
| CN216427172U (en) | N-vinyl pyrrolidone refining system | |
| CN113444029B (en) | N-vinyl pyrrolidone refining system and process | |
| KR20010075697A (en) | Process to afford gamma butyrolactone and tetrahydrofuran | |
| CN111892525A (en) | N-methyl pyrrolidone for liquid crystal panel and production process thereof | |
| CN116261559A (en) | Method and device for purifying intermediate in maltol grignard section | |
| KR101388760B1 (en) | Process for continuously preparing n-ethyl-2-pyrrolidone (nep) | |
| JP2001302626A (en) | Method for manufacturing high-purity pyrrolidone | |
| CN113549026A (en) | Synthesis process of N-vinyl oxazolidinone compound | |
| CN219050363U (en) | Acetic acid separation device in process of preparing lactic acid by straw and system for preparing lactic acid | |
| JP4348890B2 (en) | Method for purifying gamma-butyrolactone | |
| CN113527095B (en) | Synthesis and purification method of high-content chloroformic acid-2-ethylhexyl ester |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| GR01 | Patent grant | ||
| GR01 | Patent grant |