CN101391975B - Process for separation and purification of N-vinyl pyrrolidone - Google Patents
Process for separation and purification of N-vinyl pyrrolidone Download PDFInfo
- Publication number
- CN101391975B CN101391975B CN2008100720613A CN200810072061A CN101391975B CN 101391975 B CN101391975 B CN 101391975B CN 2008100720613 A CN2008100720613 A CN 2008100720613A CN 200810072061 A CN200810072061 A CN 200810072061A CN 101391975 B CN101391975 B CN 101391975B
- Authority
- CN
- China
- Prior art keywords
- rectifying tower
- falling
- film evaporator
- vinyl pyrrolidone
- tower
- 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.)
- Expired - Fee Related
Links
Images
Landscapes
- Pyrrole Compounds (AREA)
Abstract
The invention discloses a separation and purification method of N-vinyl pyrrolidone, relates to N-vinyl pyrrolidone, and provides a vacuum batch fractionating device with a falling film evaporator, and a separation and purification method of the N-vinyl pyrrolidone. , The device is provided with a storage tank, the falling film evaporator, a rectifying tower, a condenser, a reflux tank, a heat interchanger, a magnetic pump, a first receiving tank, a second receiving tank and a vacuum system. The material which contains the N-vinyl pyrrolidone and is to be separated is preheated and then sent to the falling film evaporator for evaporation, the obtained steam is led into the rectifying tower to be used as the rising steam of the rectifying tower; the rectifying tower is treated with total-reflux operation until the purity of the N-vinyl pyrrolidone in the overhead products of the rectifying tower is not less than 99.9 percent; reflux ratio is regulated by stages, and N-vinyl pyrrolidone is collected from the overhead products of the rectifying tower. The invention is suitable for the separation of heat-sensitive substances, can effectively inhibit the heat-sensitive reaction of the N-vinyl pyrrolidone and the generation of impurities and improve the recovery ratio and purity of the N-vinyl pyrrolidone.
Description
Technical field
The present invention relates to a kind of N-vinyl pyrrolidone, especially relate to a kind of method of separating purification heat-sensitive substance N-vinyl pyrrolidone with the vacuum rectifier unit at intermittence of band falling-film evaporator.
Background technology
The polymkeric substance of N-vinyl pyrrolidone is widely used in fields such as medicine, household chemicals and food.Industrially under catalyst action, carry out vinylation reaction to produce the N-vinyl pyrrolidone with 2-Pyrrolidone and acetylene usually.The transformation efficiency of general this reaction 2-Pyrrolidone is 30%～65%, and selectivity is 85%～96%.From the reaction mixture that ethylenation reactor comes out,, also contain nonvolatile catalyzer and minor by-products except that containing N-vinyl pyrrolidone and unreacted completely the 2-Pyrrolidone.As the monomer of producing polyvinylpyrrolidone, the N-vinyl pyrrolidone must reach very high purity and could use.And unreacted completely 2-Pyrrolidone also must separate and continue to utilize.Application number is the device and method that the Chinese patent application of 200510013370.X has been reported a kind of intermittent rectification under vacuum purifying N-ethane base pyrrolidone, but material heats in the tower still always in the operating process, to cause a large amount of N-vinyl pyrrolidone generation thermosensitive responses and produce impurity, thereby the N-vinyl pyrrolidone rate of recovery is lower.The generation of impurity has simultaneously also influenced the purity of the back N-vinyl pyrrolidone of purifying.The separation purification of N-vinyl pyrrolidone can also be adopted the method (referring to Chinese patent 96113099.7,01810216.6) of multistage crystallization, but processing step is various, and operation control is difficult for, and also needs just can reach separation purification purpose in conjunction with rectificating method.
Summary of the invention
The object of the present invention is to provide a kind of device that separates purifying N-ethane base pyrrolidone, promptly with the vacuum of falling-film evaporator rectifier unit intermittently.
Another object of the present invention is to provide a kind of vacuum rectifier unit at intermittence that adopts the band falling-film evaporator, the separating and purifying method of the N-vinyl pyrrolidone that technology is easy, the rate of recovery is high, product purity is high.
The vacuum of described band falling-film evaporator intermittently rectifier unit is provided with basin, falling-film evaporator, rectifying tower, condenser, return tank, interchanger, magnetic drive pump, the 1st receiving tank, the 2nd receiving tank and vacuum system.The material outlet of basin connects the material inlet of interchanger through magnetic drive pump, the material outlet of interchanger connects falling-film evaporator, the organic vapor outlet of falling-film evaporator connects the inlet of rectifying tower, the organic vapor outlet of rectifying tower connects condenser inlet, the condensed fluid outlet of condenser connects the return tank inlet, the phegma outlet of return tank connects phegma inlet and the 1st receiving tank or the 2nd receiving tank of rectifying tower respectively, the liquid of falling-film evaporator and rectifying tower returns basin after the interchanger cooling, basin is provided with cooling water jecket.
Described falling-film evaporator can be made up of 10～40 (deciding on the material treatment capacity) vertical generating tubes, and the falling liquid film sparger is equipped with at the top of every generating tube.The ratio of the pipe range of generating tube and caliber can be (100～150): 1.Falling-film evaporator can be according to known technical project and manufacturing.
Described rectifying tower is no tower still packing tower, and filler is a corrugated wire gauze packing.
The separating and purifying method of described N-vinyl pyrrolidone comprises the following steps:
1) material that contains the N-vinyl pyrrolidone to be separated is delivered to falling-film evaporator and is evaporated after preheating, and the gained steam feeds rectifying tower, as the steam that rises in the rectifying tower;
2) purity 〉=99.9% of rectifying tower total reflux operation N-vinyl pyrrolidone in the rectifying tower overhead product;
3) adjust reflux ratio stage by stage, from the overhead product of rectifying tower, collect the N-vinyl pyrrolidone.
The column bottom temperature of falling-film evaporator bottom and rectifying tower is preferably 80～135 ℃, and the tower top temperature of rectifying tower is preferably 60～100 ℃, and the absolute pressure of rectifying tower cat head is preferably 533.3Pa～2666kPa.
Reflux ratio is preferably (1.2～12): 1.
Can adopt fixedly reflux ratio 1: 1, and from the overhead product of rectifying tower, collect 2-Pyrrolidone.
The present invention is with the reboiler of falling-film evaporator as rectifying tower, compare with existing shell and tube reboiler, falling-film evaporator does not have the static pressure effect, can not cause temperature difference loss, the heat transfer temperature difference is less, evaporation is carried out under higher vacuum tightness and lower temperature, be suitable for the separation of heat-sensitive materials.The material overwhelming majority time that contains the N-vinyl pyrrolidone to be separated is under the cold conditions, time by the falling-film evaporator evaporation is very short, be that the material heated time is very short, thereby effectively suppressed the thermosensitive response of N-vinyl pyrrolidone and the generation of impurity, improved the rate of recovery and the purity of N-vinyl pyrrolidone.The reaction mixture (containing N-vinyl pyrrolidone, 2-Pyrrolidone, catalyzer and by product) that comes out from ethylenation reactor is separated into three parts through method of the present invention: the one, and highly purified N-vinyl pyrrolidone; The 2nd, contain the 2-Pyrrolidone of micro-N-vinyl pyrrolidone; The 3rd, catalyzer and by product.Highly purified N-vinyl pyrrolidone can be directly used in polymerization and produce polyvinylpyrrolidone, and the 2-Pyrrolidone that contains micro-N-vinyl pyrrolidone then can return ethylenation reactor and produce the N-vinyl pyrrolidone to continue reaction.
Description of drawings
Fig. 1 is that the structure of the vacuum rectifier unit at intermittence of band falling-film evaporator of the present invention is formed synoptic diagram.In Fig. 1,1 is basin, and 2 is falling-film evaporator, and 3 is rectifying tower, and 4 is condenser, and 5 is return tank, and 6 is interchanger, and 7 is magnetic drive pump, and 8 is the 1st receiving tank, and 9 is the 2nd receiving tank.
Embodiment
Following examples will the invention will be further described.
Referring to Fig. 1, the vacuum of band falling-film evaporator intermittently rectifier unit is provided with basin 1, falling-film evaporator 2, rectifying tower 3, condenser 4, return tank 5, interchanger 6, magnetic drive pump the 7, the 1st receiving tank the 8, the 2nd receiving tank 9 and vacuum system.The material outlet of basin 1 connects the material inlet of interchanger 6 through magnetic drive pump 7, the material outlet of interchanger 6 connects falling-film evaporator 2, the organic vapor outlet of falling-film evaporator 2 connects the inlet of rectifying tower 3, the organic vapor outlet of rectifying tower 3 connects condenser 4 inlets, the condensed fluid outlet of condenser 4 connects return tank 5 inlets, the phegma outlet of return tank 5 connects phegma inlet and the 1st receiving tank 8 or the 2nd receiving tank 9 of rectifying tower 3 respectively, the liquid of falling-film evaporator 2 and rectifying tower 3 returns basin 1 after interchanger 6 coolings, basin 1 is provided with cooling water jecket.
The material that contains the N-vinyl pyrrolidone to be separated in the basin 1 is transported to interchanger 6 through magnetic drive pump 7, delivers to falling-film evaporator 2 after preheating, and after falling-film evaporator 2 evaporations, organic vapor feeds rectifying tower 3.The organic vapor that the cat head of rectifying tower 3 comes out is condensed into liquid through condenser 4, enters return tank 5, and wherein a part is returned rectifying tower 3 as phegma, and another part extraction is collected in the 1st receiving tank 8 or the 2nd receiving tank 9.The liquid that comes out from falling-film evaporator 2 and rectifying tower 3 bottoms returns basin 1 after interchanger 6 coolings.Basin 1 has cooling water jecket, makes the material in the basin 1 remain at the state that approaches normal temperature.
Falling-film evaporator is made up of 10～40 (deciding on the material treatment capacity) vertical generating tubes, and the falling liquid film sparger is equipped with at the top of every generating tube.The ratio of the pipe range of generating tube and caliber can be (100～150): 1.Falling-film evaporator can be according to known technical project and manufacturing.
Described rectifying tower is the packing tower that does not have the tower still, and filler is the wire cloth corrugated regular filler.
Embodiment 1
2000kg consists of N-vinyl pyrrolidone 57wt%, and the mixture of 2-Pyrrolidone 40wt% and high boiling point and nonvolatile substances 3wt% separates purifying N-ethane base pyrrolidone with device shown in Figure 1.Falling-film evaporator 2 is that the vertical generating tube of 25mm is formed by 32 nominal diameters, and the ratio of the pipe range of generating tube and caliber is 120: 1.The tower diameter of rectifying tower 3 is 0.35m, filling 500 shaped metal screen waviness structured packings in the tower, and bed stuffing height is 6m.Material to be separated is squeezed in the basin 1.Open vacuum system P, make the absolute pressure of the cat head of rectifying tower 3 reach 933Pa (vacuum tightness 753mmHg).Start magnetic drive pump 7, make the material in the basin 1 behind interchanger 6, flow into falling-film evaporator 2.Open the water coolant A of condenser 4, boiling water steam B heats falling-film evaporator.Adjusting vapor pressure makes the bottom of falling-film evaporator 2 and the column bottom temperature of rectifying tower 3 reach 86 ℃.Carry out total reflux operation earlier, form with the gas chromatographic detection overhead product every 30min.When N-vinyl pyrrolidone purity 〉=99.9%, regulating reflux ratio is 1.2: 1, and collection unit fractionates out in thing to the 1 receiving tank 8.This moment, tower top temperature was 65 ℃.Along with the carrying out of rectifying, column bottom temperature rises gradually, and N-vinyl pyrrolidone purity descends to some extent in the overhead product.Progressively improve reflux ratio stage by stage until 12: 1, make that N-vinyl pyrrolidone purity is not less than 99.5% in the overhead product.Continue rectifying, when N-vinyl pyrrolidone purity drops to 99.2% in the overhead product, overhead product is collected in the 2nd receiving tank 9, and to transfer reflux ratio be 1: 1 that this moment, distilled was 2-Pyrrolidone.Proceed all to distillate until 2-Pyrrolidone, at this moment, the column bottom temperature of the bottom of falling-film evaporator 2 and rectifying tower 3 has risen to 125 ℃, and the tower top temperature of rectifying tower 3 has risen to 95 ℃.When rectifying finishes, put into the 2nd receiving tank 9 with holding liquid in the rectifying tower.The small amount of liquid that remains in the basin 1 is high boiling point and nonvolatile substances.Whole rectifying process about 4h consuming time.The result obtains N-vinyl pyrrolidone 1094.4kg in the 1st receiving tank 8, purity is 99.7%, and the rate of recovery is 96%.Obtain 2-Pyrrolidone 803.2kg in the 2nd receiving tank 9, purity is 98.6%, and the rate of recovery is 99%.
Embodiment 2
System to be separated, device and working method are with embodiment 1.Its difference is that the absolute pressure of rectifying tower cat head reaches 2666Pa (vacuum tightness 740mmHg), and the column bottom temperature of the bottom of falling-film evaporator 2 and rectifying tower 3 is 97～135 ℃, and the tower top temperature of rectifying tower 3 is 70～100 ℃.The result obtains N-vinyl pyrrolidone 1063.4kg, and purity is 99.7%, and the rate of recovery is 93%.Obtain 2-Pyrrolidone 800kg, purity is 98%, and the rate of recovery is 98%.
Embodiment 3
System to be separated, device and working method are with embodiment 1.Its difference is that the absolute pressure of rectifying tower cat head reaches 533.3Pa (vacuum tightness 756mmHg), and the column bottom temperature of the bottom of falling-film evaporator 2 and rectifying tower 3 is 82～120 ℃, and the tower top temperature of rectifying tower 3 is 60～93 ℃.The result obtains N-vinyl pyrrolidone 1109.1kg, and purity is 99.7%, and the rate of recovery is 97%.Obtain 2-Pyrrolidone 801.6kg, purity is 98.8%, and the rate of recovery is 99%.
Embodiment 4
2000kg consists of N-vinyl pyrrolidone 10wt%, and the mixture of 2-Pyrrolidone 90wt% separates purifying N-ethane base pyrrolidone with device shown in Figure 1.Falling-film evaporator 2 is that the vertical generating tube of 25mm is formed by 32 nominal diameters, and the ratio of the pipe range of generating tube and caliber is 120: 1.The tower diameter of rectifying tower 3 is 0.35m, filling 500 shaped metal screen waviness structured packings in the tower, and bed stuffing height is 6m.Material to be separated is squeezed in the basin 1.Open vacuum system, make the absolute pressure of the cat head of rectifying tower 3 reach 933Pa (vacuum tightness 753mmHg).Start magnetic drive pump 7, make the material in the basin 1 behind interchanger 6, flow into falling-film evaporator 2.Open condenser cooling water, boiling water steam heating falling-film evaporator.Adjusting vapor pressure makes the bottom of falling-film evaporator 2 and the column bottom temperature of rectifying tower 3 reach 90 ℃.Carry out total reflux operation earlier, form with the gas chromatographic detection overhead product every 30min.When N-vinyl pyrrolidone purity 〉=99.9%, regulating reflux ratio is 1.2: 1, and collection unit fractionates out in thing to the 1 receiving tank 8.This moment, tower top temperature was 65 ℃.Along with the carrying out of rectifying, column bottom temperature rises gradually, and N-vinyl pyrrolidone purity descends to some extent in the overhead product.Progressively improve reflux ratio stage by stage until 12: 1, make that N-vinyl pyrrolidone purity is not less than 99% in the overhead product.Continue rectifying, when N-vinyl pyrrolidone purity drops to 98% in the overhead product till, at this moment, the column bottom temperature of the bottom of falling-film evaporator 2 and rectifying tower 3 has risen to 100 ℃, the tower top temperature of rectifying tower 3 has risen to 70 ℃.When rectifying finishes, put into basin 1 with holding liquid in the rectifying tower.The result obtains N-vinyl pyrrolidone 191.9kg in the 1st receiving tank 8, purity is 99%, and the rate of recovery is 95%.Obtain 2-Pyrrolidone 1803.6kg in basin 1, purity is 99.7%, and the rate of recovery is 99.9%.
Embodiment 5
2000kg consists of N-vinyl pyrrolidone 90wt%, and the mixture of 2-Pyrrolidone 10wt% separates purifying N-ethane base pyrrolidone with device shown in Figure 1.Falling-film evaporator 2 is that the vertical generating tube of 25mm is formed by 32 nominal diameters, and the ratio of the pipe range of generating tube and caliber is 120: 1.The tower diameter of rectifying tower 3 is 0.35m, filling 500 shaped metal screen waviness structured packings in the tower, and bed stuffing height is 6m.Material to be separated is squeezed in the basin 1.Open vacuum system, make the absolute pressure of the cat head of rectifying tower 3 reach 933Pa (vacuum tightness 753mmHg).Start magnetic drive pump 7, make the material in the basin 1 behind interchanger 6, flow into falling-film evaporator 2.Open condenser cooling water, boiling water steam heating falling-film evaporator.Adjusting vapor pressure makes the bottom of falling-film evaporator 2 and the column bottom temperature of rectifying tower 3 reach 80 ℃.Carry out total reflux operation earlier, form with the gas chromatographic detection overhead product every 30min.When N-vinyl pyrrolidone purity 〉=99.9%, regulating reflux ratio is 1.2: 1, and collection unit fractionates out in thing to the 1 receiving tank 8.This moment, tower top temperature was 65 ℃.Along with the carrying out of rectifying, column bottom temperature rises gradually, and N-vinyl pyrrolidone purity descends to some extent in the overhead product.Progressively improve reflux ratio stage by stage until 12: 1, make that N-vinyl pyrrolidone purity is not less than 99.8% in the overhead product.Continue rectifying, when N-vinyl pyrrolidone purity drops to 99.5% in the overhead product till, at this moment, the column bottom temperature of the bottom of falling-film evaporator 2 and rectifying tower 3 has risen to 95 ℃, the tower top temperature of rectifying tower 3 has risen to 67 ℃.When rectifying finishes, put into basin 1 with holding liquid in the rectifying tower.The result obtains N-vinyl pyrrolidone 1792.8kg, and purity is 99.9%, and the rate of recovery is 99.5%.Obtain 2-Pyrrolidone 204.1kg, purity is 97%, and the rate of recovery is 99%.
Claims (6)
1. be with the vacuum rectifier unit at intermittence of falling-film evaporator, it is characterized in that being provided with basin, falling-film evaporator, rectifying tower, condenser, return tank, interchanger, magnetic drive pump, the 1st receiving tank, the 2nd receiving tank and vacuum system, the material outlet of basin connects the material inlet of interchanger through magnetic drive pump, the material outlet of interchanger connects falling-film evaporator, the organic vapor outlet of falling-film evaporator connects the inlet of rectifying tower, the organic vapor outlet of rectifying tower connects condenser inlet, the condensed fluid outlet of condenser connects the return tank inlet, the phegma outlet of return tank connects phegma inlet and the 1st receiving tank or the 2nd receiving tank of rectifying tower respectively, the liquid of falling-film evaporator and rectifying tower returns basin after the interchanger cooling, basin is provided with cooling water jecket.
2. the vacuum of band falling-film evaporator as claimed in claim 1 is rectifier unit intermittently, it is characterized in that described falling-film evaporator is made up of 10～40 vertical generating tubes, and the falling liquid film sparger is equipped with at the top of every generating tube.
3. the vacuum of band falling-film evaporator as claimed in claim 2 is rectifier unit intermittently, it is characterized in that the pipe range of generating tube and the ratio of caliber are 100～150: 1.
4. the vacuum of band falling-film evaporator as claimed in claim 1 is rectifier unit intermittently, it is characterized in that described rectifying tower is no tower still packing tower, and filler is a corrugated wire gauze packing.
5.N-the separating and purifying method of vinyl pyrrolidone is characterized in that comprising the following steps:
1) material that contains the N-vinyl pyrrolidone to be separated is delivered to falling-film evaporator and is evaporated after preheating, and the gained steam feeds rectifying tower, as the steam that rises in the rectifying tower;
2) purity 〉=99.9% of rectifying tower total reflux operation N-vinyl pyrrolidone in the rectifying tower overhead product;
3) adjust reflux ratio stage by stage, from the overhead product of rectifying tower, collect the N-vinyl pyrrolidone;
The column bottom temperature of described falling-film evaporator bottom and rectifying tower is 80～135 ℃, and the tower top temperature of described rectifying tower is 60～100 ℃, and the absolute pressure of described rectifying tower cat head is 533.3Pa～2666kPa.
6. the separating and purifying method of N-vinyl pyrrolidone as claimed in claim 5 is characterized in that reflux ratio is 1.2～12: 1.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2008100720613A CN101391975B (en) | 2008-11-03 | 2008-11-03 | Process for separation and purification of N-vinyl pyrrolidone |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2008100720613A CN101391975B (en) | 2008-11-03 | 2008-11-03 | Process for separation and purification of N-vinyl pyrrolidone |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN101391975A CN101391975A (en) | 2009-03-25 |
| CN101391975B true CN101391975B (en) | 2010-12-08 |
Family
ID=40492510
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2008100720613A Expired - Fee Related CN101391975B (en) | 2008-11-03 | 2008-11-03 | Process for separation and purification of N-vinyl pyrrolidone |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN101391975B (en) |
Families Citing this family (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102399179B (en) * | 2010-09-17 | 2014-06-18 | 上海化学试剂研究所 | Production process for ultra-pure N-methylpyrrolidone |
| WO2012120666A1 (en) * | 2011-03-09 | 2012-09-13 | 三菱化学エンジニアリング株式会社 | Device for distilling nmp |
| CN102442884B (en) * | 2011-11-11 | 2013-11-27 | 李锦记（新会）食品有限公司 | Method for recovering ethanol during soy production process and device thereof |
| CN102329296B (en) * | 2011-11-17 | 2012-12-19 | 铜陵金泰化工实业有限责任公司 | Method for rectifying high-purity propylene carbonate |
| CN103012235A (en) * | 2012-12-13 | 2013-04-03 | 中盐安徽红四方股份有限公司 | Rectification polymerization inhibition method of N-vinylpyrrolidone (NVP) |
| CN105017021B (en) * | 2014-04-24 | 2018-02-27 | 天津东大化工集团有限公司 | A kind of Ergol purifying technique |
| PL3247480T3 (en) * | 2015-01-21 | 2019-06-28 | Basf Se | Column for purification by distillation of carboxylic acid anhydrides |
| CN105693585B (en) * | 2016-04-11 | 2018-11-20 | 中芳特纤股份有限公司 | A kind of separation N-Methyl pyrrolidone/chloroform system and method |
| CN106631959B (en) * | 2017-01-04 | 2019-01-18 | 漳州华福化工有限公司 | The recovery method of 2-Pyrrolidone in n-vinyl pyrrolidone production process |
| CN107803319A (en) * | 2017-11-13 | 2018-03-16 | 林州朗坤科技有限公司 | A kind of NMP recovery purification systems and its recovery method of purification |
| CN109096169A (en) * | 2018-09-29 | 2018-12-28 | 天津科林泰克科技有限公司 | A kind of purification alpha-pyrrolidone steams the device and method of slag |
| CN111423352B (en) * | 2020-05-19 | 2024-01-02 | 上海盛剑环境系统科技股份有限公司 | Recovery system and recovery method for N-methyl-2-pyrrolidone waste liquid |
-
2008
- 2008-11-03 CN CN2008100720613A patent/CN101391975B/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| CN101391975A (en) | 2009-03-25 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN101391975B (en) | Process for separation and purification of N-vinyl pyrrolidone | |
| JP5199260B2 (en) | Acrylic acid production method | |
| CN100537507C (en) | Method and apparatus for purifying vitamin A intermediate mynistic aldehyde | |
| CN109053355B (en) | Method for purifying biphenyl by continuous rectification | |
| CN112812094A (en) | Method for purifying L-lactide | |
| JP3435598B2 (en) | Method for recovering N-vinyl-2-pyrrolidone | |
| CN108689798B (en) | Method for improving quality of methyl chloride recovered by synthesizing organic silicon monomer | |
| CN101125795A (en) | Method for preparing formic acid | |
| CN112110831A (en) | Method for synthesizing s-metolachlor-imine by heterogeneous catalytic reaction rectification | |
| CN108299151B (en) | Method for preparing 2-methylallyl chloride from 1, 2-dichlorotert-butyl alkane | |
| CN102502697A (en) | Method for recovering ammonia in morpholine solution | |
| CN1045949C (en) | Method and apparatus for producing cyclopentadience by depolymerizing dicyclopentadience | |
| CN1109861A (en) | Rectifying device for refining crude vanillin | |
| CN113233982B (en) | Device and method for obtaining high-purity methyl salicylate through continuous rectification purification | |
| EP1636178B1 (en) | Method for making caprolactam | |
| CN220801977U (en) | 3-Aminopropionitrile high-efficiency rectifying device and continuous production system | |
| EP1636179B1 (en) | Method for making caprolactam from impure 6-amino-capronitrile containing tetrahydroazepine | |
| JPWO2018105724A1 (en) | N- (α-alkoxyethyl) formamide purification method, high-purity N- (α-alkoxyethyl) formamide production method, and N- (α-alkoxyethyl) formamide purification device | |
| CN101260018B (en) | Method for synthesizing exo-tetrahydrocyclopentadiene | |
| CN102321013B (en) | Piperidone continuous refining production method and device capable of continuously recovering acetone | |
| CN206476926U (en) | A kind of gas-liquid separator for improving vinyl acetate purity | |
| CN85100107A (en) | The vacuum distillation plant that vaporization and condensation combines | |
| JPH03223224A (en) | Purification of ethylene glycol |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20101208 Termination date: 20201103 |
|
| CF01 | Termination of patent right due to non-payment of annual fee |