CN1244552C - Process for absorbing and separating phthalonitrile gas - Google Patents
Process for absorbing and separating phthalonitrile gas Download PDFInfo
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- CN1244552C CN1244552C CN 200410041028 CN200410041028A CN1244552C CN 1244552 C CN1244552 C CN 1244552C CN 200410041028 CN200410041028 CN 200410041028 CN 200410041028 A CN200410041028 A CN 200410041028A CN 1244552 C CN1244552 C CN 1244552C
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- benzene dicarbonitrile
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Abstract
The present invention relates to the improvement of an absorption extraction method for extracting phthalonitrile from gas generated by xylene, ammonia and oxygen-containing gas which reacting with each other under the existence of a catalyst, particularly to an absorption extraction method for absorbing phthalonitrile from gas generated in a reaction. The present invention is characterized in that a circulating tank behind an absorption tower enables absorption liquid absorbing the phthalonitrile and other organic impurities to be brought into the circulating tank after being discharged from the absorption tower, the absorption liquid returns to the absorption tower again and contacts the gas generated in the reaction, and the phthalonitrile is collected to form the circulation of the absorption liquid. The supplement of an absorption agent is controllable in the circulation process, the internal temperature of the absorption tower is at least maintained as higher than the dew point of water vapor, the absorption agent is charged into subsequent extraction by distillation after circulation for a plurality of times, and thereby, the control of the absorption liquid is simple and easy to execute. The absorption extraction technology of the present invention has the characteristics of high product yield, high economy, equipment investment saving, low running expenses, etc. The present invention is an ideal method for absorbing and extracting phthalonitrile from gas generated in a reaction.
Description
Technical field
The invention relates to by dimethylbenzene and ammonia and oxygen-containing gas in the presence of catalyzer in the generated reactive gas, the improvement of Separation of Benzene dimethoxy nitrile method for absorbing and separating relates in particular to from reaction and generates the method for absorbing and separating that absorbs benzene dicarbonitrile the gas.
Background technology
Benzene dicarbonitrile is called different peptide nitrile (IPN) again, is the important source material of organic synthesis.In the benzene dicarbonitrile production method, be comparatively advanced production method of present stage by the oxidation proceses of ammonia of dimethylbenzene and ammonia and oxygen-containing gas reaction, promptly in gas-solid phase fluidized bed plant, make dimethylbenzene in the presence of high temperature and catalyzer with ammonia and oxygen reaction, generation benzene dicarbonitrile.Because oxidative ammonolysis produces a large amount of reaction heat, so temperature of reaction is very high, reaction product is discharged from reactor head with gas phase (be referred to as reaction and generate gas) usually.And generate in the gas in reaction; except that containing benzene dicarbonitrile; usually also contain ammonia, hydrogenation cyanogen, carbon monoxide, carbonic acid gas, water vapor, nitrogen, oxygen, dimethylbenzene, methyl benzonitrile, cyanobenzene etc., this separates with regard to needing that reaction is generated gas, to obtain highly purified benzene dicarbonitrile.
The method that generates Separation of Benzene dimethoxy nitrile the gas from reaction has multiple, and reported by a plurality of patents and document, wherein U.S. Pat 4134910, US6509490 and Chinese patent CN1397543A, report adopts the organic solvent absorption reaction to generate gas, making wherein, benzene dicarbonitrile is trapped in (we are referred to as the single flow one way and absorb) in the lyosorption, separate through two steps of two fractionation by distillation towers again, obtain the high-purity benzene dimethoxy nitrile.Yet this organic solvent single flow one way captures and absorbs, though can obtain absorption extraction effect preferably, but still have some deficiency, for example the absorption liquid consumption is difficult to control, two kinds of situations of incomplete absorption and taken in excess can occur.
The absorption liquid consumption is excessive, tends to make the concentration of product (benzene dicarbonitrile) in absorption liquid (incomplete absorption) on the low side, not only can increase follow-up fractionation by distillation energy consumption and man-hour greatly, reduces separation and Extraction efficient; And excessive absorption liquid consumption also can cause reaction to generate the gas undercooling, when temperature is lower than under the steam dew point situation, can cause condensing or absorbing of steam.And benzene dicarbonitrile is relatively poor at water stability, in that meeting generation hydrolysis reaction under the condition of water is arranged, generates aromatic amides or aromatic carboxylic acid, thereby causes the yield of benzene dicarbonitrile to reduce.
In order to control the temperature in the absorption tower, remain on the temperature of guaranteeing absorption liquid on the dew point of steam, avoid condensing or absorbing of steam, just must the consumption of solvent be limited, again the absorption liquid quantity not sufficient can appear so often.Absorption liquid consumption very few (excessive resorption), quantity of solvent very little, the excessive concentration of reaction product in solvent can reduce because of cooling make the solubleness of benzene dicarbonitrile at pipeline equitemperature lower absorption liquid, and separate out along with the reduction of solubleness, cause the obstruction of equipment such as pipeline or pump machine.The absorption agent consumption is very few simultaneously, also can cause the absorption liquid temperature acutely to raise, can cause reaction to generate aspiration again and receive not exclusively, required benzene dicarbonitrile product can not be absorbed fully, can not coagulate with other, insoluble gas runs off from the blow-down pipe emptying, causes product yield to reduce.
Besides, owing to adopt the single flow one way to absorb, for improving absorption extraction efficient to product, therefore the solvent that must select product to be had better dissolving power is made absorption agent, rectifying must be steamed for this reason that those are separated the low impurity composition of product solubility property in the thing, just can make and reclaim solvent and be used to return absorption, to guarantee to have higher absorption efficient, though saved solvent like this, needed to increase separating treatment.
Therefore the single flow one way captures and absorbs, the absorber portion poor controllability, not only produce and be difficult to control, and it is unfavorable to high yield Separation of Benzene dimethoxy nitrile, can cause device blockage such as benzene dicarbonitrile loss and pipeline or pump machine, and steam that solvent need separate behind other impurity could reuse, therefore still having is worth improved place.
Summary of the invention
The objective of the invention is to overcome the deficiency of above-mentioned prior art, provide a kind of and have that to absorb controllability good, not only can high yield from the gas that produces by oxidative ammonolysis, reclaim benzene dicarbonitrile, but also the Absorbing And Separating Method Of Benzene Dicarbonitrile Gas that equipment such as pipeline or pump machine are stopped up that can avoid causing.
Method for absorbing and separating of the present invention, the main improvement is to make to absorb the organic solvent absorption reaction of taking to circulate and generate gas, and in circulation absorbs by the temperature of control absorption liquid, make absorption extraction be in the setting perfect condition, thereby avoid the above-mentioned unfavorable problem that may occur.Specifically, Absorbing And Separating Method Of Benzene Dicarbonitrile Gas of the present invention, thereby comprise that reaction generation gas is contacted in the absorption tower with organic solvent to be captured in benzene dicarbonitrile in the lyosorption, it is characterized in that behind the absorption tower circulation groove being arranged, make the absorption liquid that has absorbed benzene dicarbonitrile and other organic impuritys, by being introduced into this circulation groove after the discharge of absorption tower, return the absorption tower once more and contact the capture benzene dicarbonitrile with reaction generation gas, form the circulation of absorption liquid, in working cycle, controlled additional absorption agent, and make that temperature remains on the steam dew point at least in the absorption tower is sent into follow-up fractionation by distillation through circulation repeatedly after absorbing.
Temperature remains on the steam dew point at least in the said absorption tower of the present invention, main effect is to guarantee that steam can not condensed in absorption process in the reaction generation gas, and can not coagulate with other other, insoluble gas is from the blow-down pipe emptying, thereby avoid may expecting the hydrolysis of product because of condensing of steam.Be favourable control, a kind of better method of the present invention is the temperature by the Control Circulation absorption liquid, controls the temperature in the absorption tower, therefore, better is that the absorption liquid temperature is remained on the steam dew point at least.The control of absorption liquid temperature can be that heating and condenser are set in the circulation absorption circuit, and heating and condensing works also can be set in circulation groove, and a kind of comparatively easy method is that heating and condensing works (for example water cooling coil pipe) are set in circulation groove.
For avoiding temperature too high, the absorption that causes is incomplete, and the expectation product yield reduces, and absorption liquid temperature of the present invention is comparatively suitable to be controlled at 105-155 ℃.Cross and low then can cause condensation vapor or be absorbed, make that moisture increases in the absorption liquid, cause the hydrolysising loss of expectation product; Too high can causing again absorbs not exclusively and empty row, and expectation product benzene dicarbonitrile yield reduces.
The suitable concn of product in the Control Circulation absorption liquid not only can make the absorption agent utilization ratio improve, and cuts down the consumption of energy, and can improve product yield.The present invention gropes through test, and the production concentration in the circulating absorption solution is to be controlled at 15-30% for well, and wherein especially with comparatively suitable about 20-25%, concentration is low excessively, can cause the absorption agent utilization ratio to reduce, and follow-up fractionation by distillation energy consumption increases; Excessive concentration can cause product to absorb not exclusively and empty row, and recovery rate reduces.
The said additional absorption agent of the present invention can be to add new lyosorption, but a kind of be more preferably to add follow-uply steam product (light constituent and solvent) through rectifying separation, so not only help improving the utilization ratio that steams by-product, further reduce separation costs; But also avoided rectifying to steam detrimentally affect and/or minimizing environmental protection treatment expense that thing causes environment.
The present invention has the absorption liquid circulation groove owing to increasing behind the absorption tower, make absorption agent adopt the reaction of circulation absorption pattern absorption extraction to generate benzene dicarbonitrile in the gas, thereby make absorption liquid control (consumption, temperature) become simple, under the situation of incomplete absorption, can absorb by the circulation repeatedly of absorption liquid, reach and improve production concentration in the absorption liquid; Under the situation of excessive resorption, can obtain balance by in circulation groove, adding new lyosorption again.Make whole absorption technique have comparatively ideal controllability and very high economy.Temperature controlling in the absorption tower, can make and absorb the perfect condition that is in expectation, not only can make steam remain on gas phase state, and do not coagulate with other, insoluble gas, discharge from the top, absorption tower as ammonia, hydrogenation cyanogen, carbon monoxide, carbonic acid gas, nitrogen, oxygen etc., emptying is after treatment guaranteed to react the steam that generates in the gas and can not condensed in the organic solvent absorption liquid, can avoid benzene dicarbonitrile generation hydrolysis reaction to cause damage, improve the yield of benzene dicarbonitrile; But also can avoid the too high and incomplete situation of absorption that cause of absorption liquid temperature.By control absorption liquid temperature, more can easy control absorption tower in temperature.Replenish absorption agent adopt follow-up through rectifying separation steam thing (light constituent and solvent), also help the utilization ratio that improves by-product, reduce separation costs, avoided rectifying to steam the detrimentally affect that thing causes environment and/or reduced the environmental protection treatment expense.Absorption extraction technology of the present invention has product yield height, good economy performance, does not need big facility investment, characteristic such as running cost is low.
Below in conjunction with an embodiment, further specify the present invention, but the inventive method is not limited to illustrated embodiment.
Description of drawings
Accompanying drawing is an embodiment of the invention process flow sheet.
Embodiment
Embodiment: is example with m-xylene as raw material, referring to accompanying drawing.
Oxidative ammonolysis
In φ 38mm * 1800mm stainless steel fluidized-bed reactor 1, add fine particle ammoxidation catalyst 550g (the said V of Chinese patent CN1123385C for example
10Cr
aA
bB
cC
dO
xCatalyzer), feed m-xylene, ammonia and oxygen-containing gas (air) respectively, control raw material charging proportioning is: m-xylene: ammonia: air=1: 8: 41, carry out oxidative ammonolysis, about 425 ℃ of control reaction temperature, reaction generates gas and is drawn by reactor head.
The generation aspiration is received
To react and generate gas to introduce internal diameter be φ 150mm, highly be 800mm, in be filled with the stainless steel absorption tower 2 of 450mm Pall ring packing layer, spiral coil cooling tube, absorption liquid distribution pipe are housed in the absorption tower.One φ 500mm * 280mm is arranged behind the absorption tower, the stainless steel circulation groove 5 of tensimeter, thermometer, stirring rake, electric heater 4, spiral coil cooling tube 3 (water quench), safety valve is housed.Add 40 liter 1 in the circulation groove, 3,5-trimethylbenzene organic solvent, pumping enters the reaction generation circulation of vital energy in the wrong direction stream that enters with lower bottom part by top, absorption tower and contacts absorption, absorption liquid is drawn at the bottom of by tower and is pumped to circulation groove and returns circulation and absorb, do not formed as ammonia, hydrogenation cyanogen, carbon monoxide, carbonic acid gas, water vapor, nitrogen, oxygen etc., draw from the top on absorption tower, after treatment emptying by the gas phase of solvent absorbing.Pass through circulation groove internal heating or refrigerating unit in the circulation absorption process, 105-155 ℃ of Control Circulation groove absorption liquid temperature, the concentration of product in the continuous sampling analysis absorption liquid, in circulation groove, add as required by follow-up rectifying tower top and steam product (light constituent and solvent), product benzene dicarbonitrile concentration reaches 20%-25% in circulation groove, send back distillation tower fractionation by distillation with absorption liquid, removes high boiling point heavy constituent impurity, solvent and light constituent impurity get high-purity two cyanobenzene.
In addition, lyosorption of the present invention replenishes, and also can adopt to add fresh lyosorption.
The inventive method is equally applicable to produce para-Phthalonitrile and phthalonitrile with p-Xylol or o-Xylol as raw material.
Dimethylbenzene of the present invention comprises p-Xylol, m-xylene, o-Xylol.
Claims (8)
1, a kind of Absorbing And Separating Method Of Benzene Dicarbonitrile Gas, thereby comprise that reaction generation gas is contacted in the absorption tower with organic solvent to be captured in benzene dicarbonitrile in the lyosorption, it is characterized in that behind the absorption tower circulation groove being arranged, make the absorption liquid that has absorbed benzene dicarbonitrile and other organic impuritys, by being introduced into this circulation groove after the discharge of absorption tower, return the absorption tower once more and contact the capture benzene dicarbonitrile with reaction generation gas, form the circulation of absorption liquid, in working cycle, controlled additional absorption agent, and make that temperature remains on the steam dew point at least in the absorption tower, send into follow-up fractionation by distillation through circulation repeatedly after absorbing.
2,, it is characterized in that temperature control is to realize by Control Circulation absorption liquid temperature in the said absorption tower according to the described Absorbing And Separating Method Of Benzene Dicarbonitrile Gas of claim 1.
3,, it is characterized in that said circulating absorption solution temperature is at least more than the steam dew point according to the described Absorbing And Separating Method Of Benzene Dicarbonitrile Gas of claim 2.
4,, it is characterized in that said circulating absorption solution temperature is 105-155 ℃ according to the described Absorbing And Separating Method Of Benzene Dicarbonitrile Gas of claim 3.
5,, it is characterized in that said absorption liquid temperature control is to finish in circulation groove according to the described Absorbing And Separating Method Of Benzene Dicarbonitrile Gas of claim 4.
6, according to claim 1,2,3,4 or 5 described Absorbing And Separating Method Of Benzene Dicarbonitrile Gas, when it is characterized in that benzene dicarbonitrile concentration reaches 15-30% in the said circulating absorption solution, send into follow-up fractionation by distillation.
7,, when it is characterized in that benzene dicarbonitrile concentration reaches 20%-25% in the said circulating absorption solution, send into follow-up fractionation by distillation according to the described Absorbing And Separating Method Of Benzene Dicarbonitrile Gas of claim 6.
8,, it is characterized in that said additional absorption agent is the product that follow-up rectifying separation cat head steams according to the described Absorbing And Separating Method Of Benzene Dicarbonitrile Gas of claim 1.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 200410041028 CN1244552C (en) | 2004-06-18 | 2004-06-18 | Process for absorbing and separating phthalonitrile gas |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 200410041028 CN1244552C (en) | 2004-06-18 | 2004-06-18 | Process for absorbing and separating phthalonitrile gas |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1594290A CN1594290A (en) | 2005-03-16 |
| CN1244552C true CN1244552C (en) | 2006-03-08 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 200410041028 Expired - Fee Related CN1244552C (en) | 2004-06-18 | 2004-06-18 | Process for absorbing and separating phthalonitrile gas |
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Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106892840B (en) * | 2015-12-18 | 2019-04-05 | 上海泰禾国际贸易有限公司 | A method of purification para-Phthalonitrile |
| CN110256291B (en) * | 2019-07-26 | 2022-02-22 | 江阴苏利化学股份有限公司 | Method for separating phthalonitrile from high-temperature mixed gas generated by ammoxidation |
| CN113429314A (en) * | 2021-06-22 | 2021-09-24 | 四川金象赛瑞化工股份有限公司 | Ammonium nitrate and xylylenediamine coproduction method and heat exchange network |
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| Publication number | Publication date |
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| CN1594290A (en) | 2005-03-16 |
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Assignee: Dynamic (Nanjing) Chemical Industry Co., Ltd. Assignor: Jiangsu Tianying Chemical Industrial Co., Ltd. Contract fulfillment period: 2004.1.18 to 2014.1.18 contract change Contract record no.: 2008320000169 Denomination of invention: Process for absorbing and separating phthalonitrile gas Granted publication date: 20060308 License type: Exclusive license Record date: 2008.9.22 |
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Free format text: EXCLUSIVE LICENCE; TIME LIMIT OF IMPLEMENTING CONTACT: 2004.1.18 TO 2014.1.18 Name of requester: DANA (NANJING) CHEMICAL CO., LTD. Effective date: 20080922 |
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Owner name: JIANGSU TIANYIN CHEMICAL CO., LTD. Free format text: FORMER OWNER: JIANGSU TIANYIN CHEMICAL INDUSTRY CO., LTD. Effective date: 20081114 |
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Effective date of registration: 20081114 Address after: The concept of village of Jiangsu Province, Yixing Zhoutie town before Patentee after: Jiangsu Tianyin Chemical Industry Co., Ltd. Address before: The concept of village of Jiangsu Province, Yixing Zhoutie town before Patentee before: Jiangsu Tianying Chemical Industrial Co., Ltd. |
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