CN103864689B - A kind of method of the condensate liquid obtained in the evaporative crystallization steps of purification of aqueous ammonium sulfate phase - Google Patents
A kind of method of the condensate liquid obtained in the evaporative crystallization steps of purification of aqueous ammonium sulfate phase Download PDFInfo
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- CN103864689B CN103864689B CN201310661049.7A CN201310661049A CN103864689B CN 103864689 B CN103864689 B CN 103864689B CN 201310661049 A CN201310661049 A CN 201310661049A CN 103864689 B CN103864689 B CN 103864689B
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07D—HETEROCYCLIC COMPOUNDS
- C07D223/00—Heterocyclic compounds containing seven-membered rings having one nitrogen atom as the only ring hetero atom
- C07D223/02—Heterocyclic compounds containing seven-membered rings having one nitrogen atom as the only ring hetero atom not condensed with other rings
- C07D223/06—Heterocyclic compounds containing seven-membered rings having one nitrogen atom as the only ring hetero atom not condensed with other rings with hetero atoms or with carbon atoms having three bonds to hetero atoms with at the most one bond to halogen, e.g. ester or nitrile radicals, directly attached to ring carbon atoms
- C07D223/08—Oxygen atoms
- C07D223/10—Oxygen atoms attached in position 2
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01C—AMMONIA; CYANOGEN; COMPOUNDS THEREOF
- C01C1/00—Ammonia; Compounds thereof
- C01C1/24—Sulfates of ammonium
- C01C1/242—Preparation from ammonia and sulfuric acid or sulfur trioxide
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07D—HETEROCYCLIC COMPOUNDS
- C07D201/00—Preparation, separation, purification or stabilisation of unsubstituted lactams
- C07D201/02—Preparation of lactams
- C07D201/04—Preparation of lactams from or via oximes by Beckmann rearrangement
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07D—HETEROCYCLIC COMPOUNDS
- C07D201/00—Preparation, separation, purification or stabilisation of unsubstituted lactams
- C07D201/16—Separation or purification
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Abstract
The present invention is the method for preparing caprolactam, it is a kind of method for the condensate liquid for purifying and being obtained in the evaporative crystallization steps of aqueous ammonium sulfate phase, wherein described aqueous ammonium sulfate is mutually to be obtained in the presence of sulphuric acid using the Beckmann rearrangement of cyclohexanone oxime, methods described, which comprises at least, extracts and strips the step of aqueous ammonium sulfate phase is so as to produce condensate liquid, wherein the condensate liquid can be purified at least in part, during the condensate liquid purified in purification step can be re-introduced at least in part.
Description
Technical field
The present invention relates to a kind of method of the condensate liquid obtained in evaporative crystallization steps of purification of aqueous ammonium sulfate phase.This hair
It is bright to be related to a kind of method for preparing caprolactam, ammonium sulfate is formd in this method and can be from described in crystallisation step
Ammonia sulfate crystal and condensate liquid are obtained in ammonium sulfate.
Background technology
Here " method of caprolactam " refers to the synthesis for the method and step for preparing caprolactam.Therefore, the life of caprolactam
Production method also includes those steps for being applied to prepare the intermediate products of caprolactam.It is any special that the method for the present invention is not limited to
Lactams.The preferred epsilon-caprolactams of lactams.
US3,264,060, which discloses production lactams, includes the method for caprolactam.In the method, in the presence of sulfuric acid
Cycloalkanone oxime is reset by Beckmann rearrangement down, so as to obtain a kind of neutralized rearrangement mixture containing lactams.Then, in water
In the presence of neutralized rearrangement mixture is neutralized with ammoniacal liquor in neutral zone, so as to obtain it is a kind of containing aqueous ammonium sulfate solution and
The mixture of aqueous thick lactams phase.Then, the solution and aqeous thick lactams of aqueous ammonium sulfate is mutually separated each other.
Ammonium sulfate is mutually inputted in evaporator, the moisture in the evaporator in ammonium sulfate phase is partly steamed
Hair while sulfate precipitate ammonium crystal.In this process, caused mother liquor contains remaining unprecipitated ammonium sulfate.In next work
Ammonia sulfate crystal is separated so as to reclaim ammonia sulfate crystal from mother liquor using the effect of such as centrifugal separator in skill step.So
After add and be diluted with water remaining mother liquor, and the mother liquor of dilution is transported to neutral zone.Water for dilution can be by evaporator
In evaporation condensate moisture obtain condensate liquid.
WO00/66561 discloses the method for preparing caprolactam, and ammonium sulfate is formd in this method and is being crystallized
Ammonia sulfate crystal and condensate liquid can be obtained from the ammonium sulfate while condensate liquid is purified and returned it into step
Into the production process of caprolactam.The ammonium sulfate is preferably with ammoniacal liquor or aqueous ammonia and Beckmann rearrangement
Formed during mixture, wherein the Beckmann rearrangement mixture is cyclohexanone oxime utilizes Beckmann rearrangement in the presence of sulphuric acid
What reaction obtained during forming caprolactam.
Unpurified condensate liquid during ammonium sulfate crystallization, which is returned in caprolactam production process, to be caused with higher
Concentration organic pollutant and the caprolactam generation compared with high absorbance, the data measure according to ISO7059.Returned in condensate liquid
To before the production technology of caprolactam, condensate liquid is purified to produce sufficiently pure caprolactam.
Different treatments can be used to carry out the purification of condensate liquid, including being divided with activated carbon as described in WO00/66561
From, oxidation processes such as ozone processing or hydrogen peroxide treatment, UV irradiations, ion-exchanger, polymer absorbing agent, biology only
Change, UF membrane, extraction or distillation and the combination of these technologies.
In one option of methods described, evaporation water and its is cold is formed in the crystallizing evaporator for producing ammonia sulfate crystal
Condensate liquid is congealed into, purifies the condensate liquid, the purification condensate liquid of the acquisition can be applied to the weight obtained by Beckmann rearrangement
Arrange the neutral zone of mixture.In WO00/66561 embodiment 1, added into ammoniacal liquor purification condensate liquid and it is extra go from
Sub- water, wherein the ammoniacal liquor is input into neutral zone.
It is sufficiently low to have now found that the purifying technique implemented disclosed in WO00/66561 can have caused caprolactam
Absorbance, obtained according to ISO7059 measurements.Therefore, as known to the skilled person, caprolactam caused by polymerization and with logical
Chang Fangfa detects nylon-6, can produce high-quality nylon-6
But it is found that the method for purification of the condensate liquid disclosed in WO00/66561 is not still the method for a high-efficiency and economic.
Although the method for purification disclosed in WO00/66561 does not remove most pollutant and via containing active-carbon bed mistake
The preferable purification of filter generates the caprolactam of better quality, but utilizes pollutant in the condensate liquid of active-carbon bed removal
Quantity it is very big, and need displacement or regenerated carbon bed frequency it is too high and uneconomical.
Except pollutant, caprolactam can be evaporated during ammonium sulfate crystallization and due in condensate liquid caprolactam deposit
Caprolactam also can be by active-carbon bed absorption.Energy of adsorption of the caprolactam meeting restricted activity charcoal bed to any pollutant
The frequency that power is replaced or regenerated so as to improve activated carbon beds to need.Further, since used activated carbon is abandoned, activity
Absorption of the charcoal to caprolactam can cause the reduction of caprolactam total output so as to add cost.
It is well known that the contaminant problems of caprolactam are very serious when condensate liquid returns to caprolactam production process.
If however, condensate liquid is not returned to the production technology of caprolactam, it is necessary to not homologous water is added into technique.This meeting
The consumption of water is greatly enhanced, so as to cause the increase of the raising of cost and carrying capacity of environment.
Nowadays we have found it is a kind of reduce condensate liquid in pollutant burden method and therefore can maximum journey limit prolong
The life-span of the long filter used.
The content of the invention
The present invention relates to a kind of method for preparing caprolactam, the use of unnecessary water is limited in this method, is reduced
Or eliminate the problem of caprolactam is not pure enough and extend the life-span of liquor condensate filter to greatest extent.
It is an object of the present invention to by introducing the extraction step of extra ammonium sulfate and subsequent before crystallization processes
Stripping step and condensate liquid is purified before condensate liquid to be returned to preparing process of caprolactam to realize.
Therefore, the invention provides it is a kind of by the condensate liquid obtained in the evaporative crystallization steps of aqueous ammonium sulfate phase purification
Method, wherein the aqueous ammonium sulfate is mutually in presence of water, in reactant mixture ammoniacal liquor and it will obtain, reaction mixing
Thing is to be obtained in the presence of sulphuric acid using the Beckmann rearrangement of cyclohexanone oxime, be the described method comprises the following steps：
1) Beckmann rearrangement of cyclohexanone oxime is carried out in the presence of sulphuric acid；
2) with aqueous ammonia neutralization procedure 1) product obtained an aqueous ammonium sulfate phase and a crude caprolactam phase；
3) it is separated out aqueous ammonium sulfate phase from crude caprolactam；
4) crude caprolactam phase is extracted with organic solvent；
5) the aqueous ammonium sulfate phase gone out with organic solvent extract and separate；
6) strip stripped aqueous ammonium sulfate and mutually obtain a steam stripped aqueous ammonium sulfate phase and having containing organic substance
Solvent phase；
7) steam stripped aqueous ammonium sulfate is mutually crystallized, the crystallisation step contains the evaporation of water；
8) moisture that evaporates of the condensation from step 7) and caused condensate liquid is real at least in part at least in part
Apply purification step；
9) condensate liquid of purification in step 8) is introduced into step 2) at least in part.
Here term refers at least 50% weight, more preferably at least 75% weight " at least in part ", most preferably
Ground is at least 85% weight, in particular at least 90% weight.
The method that presently, there are many production caprolactams, wherein ammonium sulfate are formed at single or multiple processing step
In.In production technology cyclohexanone, cyclohexanone oxime and caprolactam may be obtained successively from benzene or toluene.Ammonium sulfate can
To be obtained by being used under the conditions of existing for water in such as ammoniacal liquor with Beckmann rearrangement mixture, wherein the Beckman weight
Row's reactant mixture is the process that cyclohexanone oxime forms caprolactam via Beckmann rearrangement under the conditions of existing for sulfuric acid
In it is obtainable.Ammonium sulfate can also be formed in the process for preparing azanol, and the azanol is used to form cyclohexanone by cyclohexanone
In the reaction of oxime.
The production method that the method for the present invention is not limited to any caprolactam is also not necessarily limited to any formation ammonium sulfate
Processing step.The production method of the caprolactam is included according to so-called (improved) Raschig technologies, based on an oxidation
The hydrogenation technology of nitrogen, based on ammoxidation technology andThe method of intermediate prepared by technology.One in these production technologies
Or multiple possibility can be combined with the technology for implementing a step and multistep Beckmann rearrangement under the conditions of existing for sulfuric acid.It is logical
The reactant mixture obtained in conventional ammoniacal liquor and after Beckmann rearrangement is so as to forming ammonium sulfate.
Then, it is separated out aqueous ammonium sulfate phase from crude caprolactam.
To reach certain purity, the aqueous ammonium sulfate phase of organic solvent extract and separate need to be used.Preferably, organic solvent can
To be toluene or benzene, wherein most preferably benzene.The extraction step eliminates caprolactam and other from aqueous ammonium sulfate phase
Organic pollution.
Then, the stripped aqueous ammonium sulfate is stripped mutually so as to generate a steam stripped aqueous ammonium sulfate phase and one
Organic solvent phase.Stripped aqueous ammonium sulfate phase can be stripped using steam stream.Can following current or adverse current strip stripped contain
Water ammonium sulfate phase, and preferred adverse current strips.For steam, any inert vapor, but preferred water vapour can be used.Stripping is usual
Carried out in packed tower or plate column.
By in step 4) organic solvent extraction obtain organic caprolactam mutually may be processed in many approach with
Produce high-quality caprolactam.One of these approach are included in phase of the back extraction containing organic caprolactam in aqueous phase and contained with obtaining
The phase of water caprolactam, it is optional after the strip stage that ion-exchange treatment, hydrogenation impurity treatment are carried out to caprolactam, is steamed
Evaporate water and final distillation processing.
Another approach includes cleaning and gone containing organic caprolactam phase, distillation removal organic solvent, hydrogenation impurity, distillation
Water, distillation remove light fraction and finally distill caprolactam.
Preferably with water or alkaline moisture solution cleaning step 4) in organic solvent extraction obtain organic caprolactam
Phase.The alkali concn of the aqueous solution is relative to water typically in 0.01% weight between 5% weight.Preferably, alkali concn
For 0.1-2% weight.It is preferred that cleaned with water or with the water containing the extremely low aqueous slkali of alkali content.Generally by alkaline (alkaline earth) hydrogen
Oxide and/or carbonate are as alkali.It is preferred that use sodium hydroxide or potassium hydroxide.
Those skilled in the art can determine that the water of phase of the cleaning containing organic caprolactam.In general, relative to organic
The amount of phase, the water are 0.1-5% weight.Preferably, relative to the amount of organic phase, the water is 0.5-2% weight.Have
After machine mutually cleans, increased water in organic phase and organic phase is usually evaporated.So as to form caprolactam/aqueous mixtures.
The content of caprolactam is the 85-99.9% weight of gross weight in the mixture.So water is 0.1-15% weight here.
The further purification of caprolactam/aqueous mixtures can use a variety of technical methods, such as use ion exchange
Agent, adsorbent or method for hydrogenation.Preferably, hydrogenated caprolactam/aqueous mixtures further purify.Can using art processes
Implement hydrogenation.EP0635487 describes a suitable method for hydrogenation.
In order to obtain pure anhydrous caprolactam, water can be distilled out from caprolactam.Finally, will using distillation
Higher boiling composition removes from the caprolactam of the drying obtained.
Another advantage is that the organic solvent from step 5) and step 6) can mutually reclaim in process of production and
Recycle.
Preferably, the organic solvent of step 5) mutually at least part of after being condensed can be used for extraction step 4) it is thick in oneself
Acid amides phase；
Preferably, the organic solvent of step 6) is used at least partially for purification step 4 after being mutually recovered) crude caprolactam
Phase.
Preferably, after the organic solvent of step 6) is mutually recovered and use it for extraction step 5 at least in part) contain
Water ammonium sulfate phase.
The unpurified condensate liquid that step 9) obtains contains organic pollution, and the pollutant includes such as cyclohexanone oxime, benzene
Amine, the especially material such as octahydro azophenlyene.In unpurified condensate liquid, especially with ammoniacal liquor or aqueous ammonia and neutralized rearrangement mixture
The octahydro azophenlyene of the organic pollution, especially high concentration that are found that high concentration is formed in ammonium sulfate, wherein the rearrangement
Mixture obtains in condition cyclohexanone oxime existing for sulfuric acid generates caprolactam process via Beckmann rearrangement.
Above-mentioned pollutant present in the condensate liquid that step 9) obtains is wondrous, because to crystallisation step 8) addition
The aqueous sulfuric acid ammonium salt solution from step 6) in do not find the pollutant., can be with default of the rationale of science
Think that the precursor of above-mentioned organic pollution is present in the ammonium sulfate that is added in crystallizer and in crystallisation step 7) in shape
Into above-mentioned organic pollution.In addition, the condensate liquid surprisingly obtained in step 8) contains having for such as octahydro azophenlyene
Organic pollutants, the pollutant have 355-365 DEG C of boiling point under 1bar (about 100kPa) pressure.Considering as described below
People are not intended to octahydro azophenlyene in condensate liquid be present during crystallizer operation temperature, because it has higher boiling point.
Crystallisation step 7 is mutually implemented to steam stripped aqueous ammonium sulfate), the step contains the evaporation of water.
The method according to the invention, ammonia sulfate crystal is mutually obtained from aqueous ammonium sulfate using moisture is evaporated in crystallisation step.
This is usually realized in crystallizer.The example of crystallizer can be found in Don W.Green and James O.Maloney and compile for 1997
" Perry's Chemical Engineers Handbook " the 18th the 44-55 pages of the part write.The operation temperature of crystallizer
It is not strict with pressure.Crystallizer is 20-80 DEG C generally in temperature, and pressure is 20mbar (about 2kPa) to 8bar (about 800kPa)
Under conditions of operated.Preferably, the operation temperature of crystallizer be 40-130 DEG C, operation pressure be 50mbar (about 5kPa) extremely
Between 2bar (about 200kPa).
The ammonium sulfate concentrations being added in the ammonium sulfate phase of crystallizer are generally 25%-50% weight, are especially 35%-
45% weight.The COD for being added to ammonium sulfate phase in crystallizer (uses KMnO4Oxidizing process determines) it is generally 0.1-20g/
Kg, preferably 0.2-15g/kg, in particular 0.3-10g/kg.
Therefore, in crystallisation step, the evaporation water of step 7) is condensed so as to obtain condensate liquid in step 8).With for example hot
Exchanger cooling evaporation water can realize above-mentioned condensation.
The condensed water of step 8) contains up to 5mg/kg octahydros azophenlyene, is determined by HPLC (UV E290mm), preferably up to
3mg/kg octahydro azophenlyene, most preferably up to 1mg/kg octahydros azophenlyene.
Then purification step is implemented to condensate liquid.The purification of condensate liquid can be realized by number of ways.Preferably with activity
Charcoal is purified.It is also possible that above-mentioned technology and oxidation processes, which are combined,.Oxidation processes include for example, ozone processing and/or
Hydrogen peroxide treatment, and/or UV treatment with irradiation.Using well known to a person skilled in the art above-mentioned technology purification of aqueous steam.
" the Handbook of edited by Ronald W.Rousseau that John Wiley＆Sons publishing company in 1987 publishes
Separation Process Technology " describe many such purification techniques.With the purification such as 651- of activated carbon
Described in page 653." the Chemical Engineer's edited by John H.Perry that McGraw-Hill publishing company publishes
Handbook " fourth editions have inquired into absorption and ion-exchanger.
In the present invention, it is preferred to use activated carbon is purified.It is preferred that granular active carbon, because its size, surface area
It is more balanced with drooping characteristic aspect.Particularly preferred Norit ROX 0.8, Chemviron Filtrasorb 300, YH Shell
20-40, the Ji Bei Yanshan Mountain, Chengde activated carbon Co., Ltd YH-11Shell 10-24 and Huaibei activated carbon carbon company YH Shell
8-16。
The reduction of each and any organic principle concentration is all favourable.Preferably, the purification of step 8) is cold
Lime set contains<3mg/kg octahydro azophenlyene, more preferably<1mg/kg, it is most preferably<0.5mg/kg, in particular<
0.02mg/kg, determined by HPLC (UV E290nm).
Preferably, in technique of the invention, the dosage of the activated carbon (fresh or regeneration) for purifying condensate liquid is
Less than 1kg caprolactams per ton, more preferably less than 0.7kg caprolactams per ton, even more preferably less than 0.5kg acyls per ton in oneself
Amine, most preferably in less than 0.25kg caprolactam per ton.
The condensate liquid of purification return to caprolactam produce technique in make caprolactam than do not carry out condensate liquid purification but its
Caprolactam caused by his step identical production technology is purer.Condensate liquid is allowed to return to life according to present invention purification condensate liquid
The purity of caprolactam does not have any serious reduction simultaneously in production. art.According to the present invention, condensate liquid is returned and can greatly be dropped
Low water consumption.
In the method for the present invention, the condensate liquid of purification can be returned to the different phase in caprolactam preparation process.Carry
The example in the stage that pure condensate liquid is likely to return to includes the preparatory phase of azanol, the preparatory phase of cyclohexanone oxime, Beckman
The neutralization for the neutralized rearrangement mixture that rearrangement reaction obtains and caprolactam purification phase.
One embodiment of the invention elaborates the caprolactam obtained according to the inventive method.
Caprolactam preferably contains as caused by obtaining the inventive method<3mg/kg octahydro azophenlyene, more preferably<1mg/
Kg, most preferably<0.5mg/kg, in particular<0.2mg/kg, determined (UV E290nm) by HPLC.
Therefore, we can be found that extraction is aqueous when extending the usage time of activated carbon as far as possible for economic aim
Ammonium sulfate, then carry out stripping stripped aqueous sulfuric acid ammonium salt solution and molten by steam stripped aqueous ammonium sulfate is partly evaporated
Caused condensate liquid, which carries out purification, after liquid can significantly reduce the concentration of organic pollution, and particularly unsaturated compoundses is dense
The concentration of octahydro azophenlyene in degree and condensate liquid.
Brief description of the drawings
The present invention is by following figure come more thorough explanation.
Fig. 1 describes prior art, as exemplified by WO00/66561.
The embodiment that Fig. 2 elaborates the inventive method.
In Fig. 1, Beckmann rearrangement mixture [1] and aqueous ammonia [4] are added to neutral zone [A].Obtained in neutral zone [A]
Neutralization mixture containing aqueous sulfuric acid ammonium salt solution and aqueous crude caprolactam.Conveying neutralizes mixture [5] and arrives separator
[B], aqueous sulfuric acid ammonium salt solution and aqueous crude caprolactam are separated from each other by being separated there.Aqueous crude caprolactam [6]
Separator [B] is left with aqueous sulfuric acid ammonium salt solution [7].Subsequent ammonium sulfate [7] enters crystal region [E].[E] contains for crystal region
One or more crystallizers and one or more liquid-crystal separation equipments.The ammonia sulfate crystal that crystal region [E] is formed is with streamer [13]
Leave crystal region [E].Optionally, the mother liquor in streamer [17] is removed.Crystal region [E] water condensation evaporated is condensed into condensation
Liquid.Condensate liquid [14] is transported to adsorption zone [F].Adsorption zone [F] is made up of one or more equipment full of activated carbon.
The condensate liquid [15] of purification is discharged from adsorption zone [F].The addition deionized water [16] into the condensate liquid [15] of purification,
So as to obtain the current of mixing [3].Gaseous state or aqueous ammonia [2] are added to streamer [3], so as to obtain available for neutral zone [A]
Aqueous ammonia [4].Extraction purification of aqueous crude caprolactam [6] (Fig. 1 is not shown) in organic solvent is utilized afterwards.
In Fig. 2, Beckmann rearrangement mixture [1] and aqueous ammonia [4] are added to neutral zone [A].Obtained in neutral zone [A]
Neutralization mixture containing aqueous sulfuric acid ammonium salt solution and aqueous crude caprolactam.Conveying neutralizes mixture [5] and arrives separator
[B], aqueous sulfuric acid ammonium salt solution and aqueous crude caprolactam are separated from each other by being separated there.Aqueous crude caprolactam [6]
Separator [B] is left with aqueous sulfuric acid ammonium salt solution [7].It is aqueous with the organic solvent extraction being added in [8] in extractor [C]
Ammonium sulfate [7].Organic streamer containing organic solvent, caprolactam and organic pollution is left by [9] and for aqueous
The extraction of crude caprolactam (Fig. 2 is not shown).The stripped aqueous sulfuric acid ammonium salt solution of stripping in stripper [D] afterwards
[10].Any remaining organic solvent is removed by line [11] and the extraction of aqueous crude caprolactam can be used it for after condensation
Or the extraction of aqueous sulfuric acid ammonium salt solution (Fig. 2 is not shown).
Steam stripped ammonium sulfate [12] enters crystal region [E].Contain one or more crystallizers and one in crystal region [E]
Or multiple liquid-crystal separation equipments.The ammonia sulfate crystal that crystal region [E] is formed leaves crystal region [E] with streamer [13].Optionally,
Remove the mother liquor in streamer [17].Crystal region [E] water cooling evaporated is congealed into condensate liquid.Condensate liquid [14] is transported to adsorption zone
[F].Adsorption zone [F] is made up of one or more equipment full of activated carbon.
The condensate liquid [15] of purification is discharged from adsorption zone [F].The addition deionized water [16] into the condensate liquid [15] of purification,
So as to obtain the current of mixing [3].
Gaseous state or aqueous ammonia [2] are added to streamer [3], so as to obtain aqueous ammonia [4], the aqueous ammonia [4] is subsequently used in
Neutral zone [A].
Then with the aqueous crude caprolactam of organic solvent purification by liquid extraction [6] (Fig. 2 is not shown).
Embodiment
The present invention is further illustrated by following embodiment, but not limited to this.
Embodiment 1
In the present embodiment, methods described is as shown in Figure 2.
According to DSMIn the business cyclohexanone oxime production plant of technical work, it will be dissolved in using hydrogen aqueous
The nitrate reduction of solution is into azanol.The azanol of acquisition produces cyclohexanone oxime with hexamethylene reactive ketone.After purifying cyclohexanone oxime, it will obtain
Cyclohexanone oxime mix with excessive oleum it is (average to produce 17 tons of oneself interior acyls per hour so as to convert thereof into caprolactam
Amine).The Beckmann rearrangement mixture [1] obtained and aqueous ammonia [4] are added to neutral zone [A].The temperature of neutral zone [A] is maintained at
50℃.The neutralization mixture containing aqueous ammonium sulfate and aqueous crude caprolactam is obtained in neutral zone [A].Neutralize mixture
PH is 4.5.
Mixture [5] input separator [B] will be neutralized, aqueous sulfuric acid ammonium salt solution and aqueous crude caprolactam are in the separator
It is separated from each other by being separated.Crude caprolactam phase streamer [6] is made up of the water of 30% weight and the caprolactam of 70% weight,
Aqueous ammonium sulfate [7] phase streamer leaves separator [B] simultaneously, and the aqueous ammonium sulfate is the ammonium sulfate and 58% weight by 42% weight
The water composition of amount.
The content of caprolactam is 1% weight in aqueous ammonium sulfate [7] phase.Aqueous ammonium sulfate [7] is mutually in counter-current operation
Extraction adds almost purified petroleum benzin by line [8] simultaneously in extractor [C].Organic stream containing benzene, caprolactam and organic pollution
Note leaves extractor [C] and for the extraction of crude caprolactam by line [9].
Stripped aqueous ammonium sulfate is mutually left by line [10] from the bottom of extractor [C] and subsequently enters steam stripping tower
[D].COD (the KMnO of stripped aqueous sulfuric acid ammonium salt solution [10]4The COD of oxidizing process measure) it is 2250ppm weights
Amount.The concentration of benzene and caprolactam in stripped aqueous sulfuric acid ammonium salt solution [10] is respectively 35 and 30ppm weight.Steam vapour
Almost all of benzene is removed by line [11] in stripper [D].By the benzene that line [11] removes in purification caprolactam and ammonium sulfate
Reclaim and reuse during phase.The content of benzene is less than 0.1ppm weight in steam stripped aqueous ammonium sulfate [12].
Then steam stripped aqueous ammonium sulfate [12] enters crystal region [E].Crystal region [E] is by one group of Oslo type evaporative crystallization
Device form, its operation temperature be 50-110 DEG C, pressure between 100mbar (about 10kPa) to 1.1bar (about 110kPa) and
Centrifugal separator is as liquid-crystal separation equipment.
The ammonia sulfate crystal that crystal region [E] is formed leaves crystal region [E] with streamer [13].Remove the mother in streamer [17]
Liquid.The water cooling that crystal region is evaporated is congealed into condensate liquid [14].The concentration of octahydro azophenlyene is 0.52mg/kg in condensate liquid [14], by
HPLC (UV E290nm) is determined.Adsorption zone [F] is made up of the pillar full of activated carbon granule of two operation repetitives.Norit
ROX 0.8 (steam activation, acid elution, the activated carbon of extrusion pressing type) is used as adsorbent.The effective volume for flowing into each pillar is
0.5m3Activated carbon condensate liquid per ton (=1800m per hour3Activated carbon condensate liquid per ton is per second).The temperature of condensate liquid [14] is about
65℃.The amount of the condensate liquid of activated carbon processing is 2.7 tons of caprolactams per ton of the moon.
The condensate liquid [15] of purification is discharged from adsorption zone [F].The concentration of octahydro azophenlyene is low in the condensate liquid [15] of purification
In 0.01mg/kg, determined by HPLC (UV E290nm).
The addition deionized water [16] into the condensate liquid [15] of purification, so as to obtain current [3].
Then the aqueous crude caprolactam that the technology purification in WO98/49140 is removed by line [6].Obtain oneself
Lactams has the octahydro azophenlyene that concentration is less than 0.01mg/kg, is determined by HPLC (UV E290nm).
By 36 months by a definite date, the concentration of octahydro azophenlyene in condensate liquid [14] can be reduced to by the activated carbon of adsorption zone [F]
(determined less than 0.01mg/kg by HPLC (UV E290nm)).After this period, with new material substitution adsorption zone [F]
Activated carbon.In the period, high-quality caprolactam is generated.The consumption of fresh activity charcoal be about 0.1kg it is per ton oneself
Lactams.
Comparative example A
This method as described in Example 1, only difference is that not to stripped aqueous sulfuric acid ammonium salt solution [10] carry out
Stripping.Stripped aqueous sulfuric acid ammonium salt solution [10] is added directly into crystal region [E].The aqueous sulfuric acid ammonium salt solution [10] of extraction
With average about 2250gram per m3The COD of aqueous sulfuric acid ammonium salt solution of extraction (use KMnO4The chemical oxygen demand of oxidizing process measure
Amount) content.This includes the benzene of the 35ppm weight of HPLC (UV E290nm) measure.
Water in crystal region [E] is then condensed by evaporation.In addition to water, volatile compound is also all evaporated and coagulated
Knot.Volatile compound of the condensate liquid [14] in addition to containing water also containing condensation, including benzene and octahydro azophenlyene.
In the comparative example, the time for the activated carbon saturation for making adsorption zone [F] is simulated.The activated carbon of saturation is not
The condensate liquid of input is purified again.In general, occur just to have discovered that before complete activated carbon saturation penetrate it is (endless
Full absorption).
The activated carbon in adsorption zone [F] is set to be less than 2100hrs the time required to reaching saturation.This is less than 3 months continuous
Production.
The usage time (36 months) of activated carbon and comparative example A in adsorption zone [F] described in embodiment 1 are simulated
Result (3 months) contrast, clearly show and introduce steam stripping device [D] and the usage time of activated carbon can be extended more than 12
Times.The consumption of fresh activity charcoal is about 1.2kg caprolactams per ton.
Comparative example B
This method as described in Example 1, only difference is that to aqueous sulfuric acid ammonium salt solution [7] do not carry out extraction and then
Also it is not stripped.Methods described is as shown in Figure 1.Addition aqueous sulfuric acid ammonium salt solution [7] arrives crystal region [E].Aqueous sulfuric acid
Organic matter content in ammonium salt solution [7] is averagely about 1% weight.The organic substance is mainly caprolactam.
Crystal region [E] interior water is then condensed by evaporation.In addition to water, volatile compound is also all evaporated and condensed.
Composition and any residuals from crystallizer are evaporated all finally in condensate liquid [14].Therefore, condensate liquid [14] can contain
Water and residual component, including caprolactam and the volatile ingredient of condensation, including octahydro azophenlyene.Analysis shows caprolactam and 6-
Aminocaproic acid calculates 1000 between 2000ppm weight together.(6-aminocaprolc acid is the linear response production of caprolactam and water
Thing).
In the comparative example, the time for the activated carbon saturation for making adsorption zone [F] is simulated.The activated carbon of saturation is not
The condensate liquid of input is purified again.In general, occur just to have discovered that before complete activated carbon saturation penetrate it is (endless
Full absorption).
The activated carbon in adsorption zone [F] is set to be less than 125hrs the time required to reaching saturation.This is only the continuous production of 5 days.
By the result pair that the usage time of activated carbon and comparative example B are simulated in the adsorption zone [F] described in embodiment 1
Than clearly showing and introducing the usage time extension of extractor [C] and steam stripping tower [D] meeting by activated carbon more than 200 times.
The consumption of fresh activity charcoal is about 22kg caprolactams per ton.
Claims (11)
- A kind of 1. method of the condensate liquid obtained in evaporative crystallization steps of purification of aqueous ammonium sulfate phase, wherein the aqueous sulfuric acid Ammonium is mutually to be obtained in presence of water with ammoniacal liquor neutralization reaction mixture, and the reactant mixture is to utilize ring in the presence of sulphuric acid What the Beckmann rearrangement of hexanone oxime obtained, it the described method comprises the following steps：1) Beckmann rearrangement of cyclohexanone oxime is carried out in the presence of sulphuric acid；2) with aqueous ammonia neutralization procedure 1) product obtained an aqueous ammonium sulfate phase and a crude caprolactam phase；3) aqueous ammonium sulfate phase is isolated from crude caprolactam phase；4) crude caprolactam phase is extracted with organic solvent；5) aqueous ammonium sulfate gone out with organic solvent extract and separate mutually produces stripped aqueous ammonium sulfate phase and comprising organic matter Organic phase；6) strip stripped aqueous ammonium sulfate and mutually obtain a steam stripped aqueous ammonium sulfate phase and the phase containing organic substance；7) steam stripped aqueous ammonium sulfate is mutually crystallized, the step contains the evaporation of water；8) by least condensate moisture of the 50 weight % evaporation from step 7) and by least 50 weight % caused condensation Liquid implements the purification step using activated carbon；9) condensate liquid of purification at least 50 weight % step 8) is introduced into step 2).
- 2. method according to claim 1, wherein the extraction for the aqueous ammonium sulfate phase isolated with benzene.
- 3. the organic phase of method according to claim 1, wherein step 5) is used for extraction step 4) crude caprolactam phase.
- 4. method according to claim 1, wherein recycling step 6) the phase containing organic substance and by its at least 50 weight Amount % be used for extraction step 4) crude caprolactam phase.
- 5. method according to claim 1, wherein recycling step 6) the phase containing organic substance and by its at least 50 weight Amount % be used for extraction step 5) in the aqueous ammonium sulfate phase isolated.
- 6. method according to claim 1, wherein utilizing active-carbon bed purification step 8) condensate liquid.
- 7. method according to claim 1, wherein, for purification step 8) the fresh activity charcoal of condensate liquid that obtains or regeneration The consumption of activated carbon is less than 1kg caprolactams per ton.
- 8. according to the method for claim 1, wherein, for purification step 8) the fresh activity charcoal or again of condensate liquid that obtains The consumption of liveliness proof charcoal is less than 0.5kg caprolactams per ton.
- 9. the condensate liquid of method according to claim 1, wherein step 8) contains 5mg/kg octahydros azophenlyene altogether.
- 10. the purification condensate liquid of method according to claim 1, wherein step 8) contains<3mg/kg octahydro azophenlyene.
- 11. the purification condensate liquid of method according to claim 1, wherein step 9) contains<0.2mg/kg octahydro azophenlyene.
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| CN105061311B (en) * | 2015-08-13 | 2017-12-01 | 江苏三鼎石化科技有限公司 | A kind of process for refining of caprolactam |
| CN107118156B (en) * | 2017-06-26 | 2020-08-28 | 山东清创化工有限公司 | Caprolactam separation and refining process |
| CN108341763B (en) * | 2018-04-24 | 2020-12-01 | 河北美邦工程科技股份有限公司 | Caprolactam crystallization and purification method |
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