CN1071750C - Process for the selective separation of morpholine - Google Patents
Process for the selective separation of morpholine Download PDFInfo
- Publication number
- CN1071750C CN1071750C CN96191128A CN96191128A CN1071750C CN 1071750 C CN1071750 C CN 1071750C CN 96191128 A CN96191128 A CN 96191128A CN 96191128 A CN96191128 A CN 96191128A CN 1071750 C CN1071750 C CN 1071750C
- Authority
- CN
- China
- Prior art keywords
- morpholine
- methylmorpholine
- cationite
- nmmo
- aqueous solution
- 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
Classifications
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07D—HETEROCYCLIC COMPOUNDS
- C07D295/00—Heterocyclic compounds containing polymethylene-imine rings with at least five ring members, 3-azabicyclo [3.2.2] nonane, piperazine, morpholine or thiomorpholine rings, having only hydrogen atoms directly attached to the ring carbon atoms
- C07D295/02—Heterocyclic compounds containing polymethylene-imine rings with at least five ring members, 3-azabicyclo [3.2.2] nonane, piperazine, morpholine or thiomorpholine rings, having only hydrogen atoms directly attached to the ring carbon atoms containing only hydrogen and carbon atoms in addition to the ring hetero elements
- C07D295/023—Preparation; Separation; Stabilisation; Use of additives
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07D—HETEROCYCLIC COMPOUNDS
- C07D295/00—Heterocyclic compounds containing polymethylene-imine rings with at least five ring members, 3-azabicyclo [3.2.2] nonane, piperazine, morpholine or thiomorpholine rings, having only hydrogen atoms directly attached to the ring carbon atoms
- C07D295/22—Heterocyclic compounds containing polymethylene-imine rings with at least five ring members, 3-azabicyclo [3.2.2] nonane, piperazine, morpholine or thiomorpholine rings, having only hydrogen atoms directly attached to the ring carbon atoms with hetero atoms directly attached to ring nitrogen atoms
- C07D295/28—Nitrogen atoms
Abstract
The invention is concerned with a process for the selective separation of morpholine from an aqueous solution containing morpholine, N-methylmorpholine and N-methylmorpholine-N-oxide, characterized by the following steps: (A) passing said aqueous solution over a cation exchanger capable of adsorbing morpholine in such an amount until it cannot be charged substantially with morpholine any more and an eluate substantially free from morpholine but containing N-methyhnorpholine and N-methylmorpholine-N-oxide is obtained, and (B) regenerating the cation exchanger charged with morpholine and reusing it in step (A).
Description
The present invention relates to the method for selective separation of morpholine from the aqueous solution that contains morpholine, N-methylmorpholine and N-methylmorpholine-N-oxide compound.In particular, the present invention relates to handle the method for the aqueous process fluid (ProzeBflussigkeit) of the amine oxide method that contains morpholine, N-methylmorpholine and N-methylmorpholine-N-oxide compound.
Recent decades, seeking to prepare the method for shaped cellulose bodies, can replace the viscose process that extensively adopts now always.As because of more adapting to the also interesting a kind of possibility method of environmental requirement, found cellulose dissolution with underivatized in organic solvent, and from this solution extrusion die goods, for example process of fiber, film and other moulded product.The fiber of extruding like this obtains generic name Lyocell from BISFA (regenerated fiber stdn international office).Be interpreted as the mixture of organic chemicals and water for organic solvent B ISFA.
Verified, the mixture particularly suitable of tertiary amino oxides and water is used to prepare shaped cellulose bodies as organic solvent.What wherein at first use as amine oxide is N-methylmorpholine-N-oxide compound (NMMO).Other amine oxide for example also has explanation in EP-A-0553070.The method of the mouldable cellulose solution of known preparation from EP-A-0356419 for example.For the purpose of this specification sheets and these claims, use tertiary amino oxides to prepare the so-called amine oxide method of process of shaped cellulose bodies.
Described the amine oxide method for preparing spinnable cellulose solution in EP-A-0356419, this method adopts the suspension of Mierocrystalline cellulose in liquid aqueous N-methylmorpholine-N-oxide compound (NMMO) as starting raw material etc.This method is to make suspension step and be transformed into mouldable solution continuously in the film treatment unit.At last, mouldable solution is by shaping jig, and for example spinning nozzle is spun into long filament, makes long filament pass through settling bath then.
Mierocrystalline cellulose precipitates in settling bath.Tertiary amino oxides is enrichment in settling bath.Can contain the amine oxide that is up to 30% (weight) in the settling bath.For the economy of amine oxide method, more extremely important is as far as possible fully to reclaim amine oxide and be reused for the mouldable cellulose solution of preparation.Therefore be necessary from settling bath, to reclaim NMMO.
The known method that from dilute aqueous soln, reclaims NMMO from DD-A-274 435.According to this method, make the aqueous solution by filling band SO
3The exchange column of the vinylbenzene/divinyl benzene copolymer of H group until reaching mole such as maximum load, is discharged NMMO with the sodium hydroxide solution of equimolar amount subsequently, and with sour exchange column is regenerated.
Except amine oxide, the also enrichment in settling bath of the degraded product of amine oxide method.These degraded products possibility colors are very dark, and therefore make the debase of the shaped cellulose bodies of generation.On the other hand, other material also means the anxious trouble of safety, because under given conditions, amine oxide often is easy to the intensive exothermal decomposition reactions takes place, and these decomposition reactions can be caused by some material or quicken.These materials must concentrate with separate NMMO before from want the regenerated settling bath, remove.
Remove after these unwanted materials, extract water outlet from the settling bath that purifies, also optional other process water that is combined with the amine oxide method of settling bath is as the steam condensate that generates in preparation cellulose solution process.This can for example can be undertaken by evaporative process.Contain the high-concentration aqueous amine oxide in the resistates of evaporative process, it can be recycled in the amine oxide method.Steam in the evaporative process mainly contains water, but wherein is dissolved with a large amount of N-methylmorpholines, i.e. the main degradation products of NMMO.And, also contain NMMO and morpholine in the steam.Generally speaking, every liter of steam contains the N-methylmorpholine of the NMMO, the 240mg that are up to 100mg and the morpholine of 30mg.These steam are for example concentrated easily by the inverse osmosis effect.The resulting aqueous solution generally contains the NMMO that is up to 4g, be up to the N-methylmorpholine of 10g and be up to the morpholine of about 1g.
By EP-A-0 402 347 as can be known, amine can be separated from the waste water of Mierocrystalline cellulose processing by cationite.Cationite has carboxylic group as functional group.For wash-out amine, handle the cationite that is loaded with amine subsequently with the weakly acidic aqueous solution of pKa value＞3.0.Elutriant is carried out fractionation by distillation.When fractionation by distillation, with a part of weak acid and amine is separated and under possible situation with its recovery.Two kinds of amine are separated to from waste water from the aqueous solution that contains N-methylmorpholine and morpholine with this method and are up to 94%.Isolated amine is got rid of by burning.
Known in addition, morpholine, N-methylmorpholine and NMMO can separate (V.Grilc and N.Zitko, the recovery of morpholine together by ion-exchanger from waste water; Chem.Biochem.Eng.Q.6 (4), 189-193 (1992)).
EP-A-0 468 951 has described a kind of from the aqueous solution, or rather the method for separation of amine oxide compound from add the waste water that produces man-hour at Mierocrystalline cellulose particularly.According to this currently known methods, make waste water and have the cationite of carboxylic group and contact as functional group, so that cationite load amine oxide, then wash load cationite and handle amine oxide with the weakly acidic aqueous solution of pKa-value＞3.0, with the wash-out amine oxide.The purpose of this method also is fully amine oxide to be separated from waste water, so that do not cause trouble to environmental protection.
In the amine oxide method, should keep the consumption of NMMO as far as possible little.Also N-methylmorpholine should be oxidized to NMMO again and return.Oxidizing reaction is for example finished with the peroxidation oxygenant.
For example, prepare the method for tertiary amino oxides product by the oxygenizement of tertiary amine by known among the EP-A-0092862.According to this method, under pressure, in water-containing solvent, use the molecular oxygen oxidation amine oxide, the pH value of described solvent approximates or is higher than the PKa value of tertiary amine.
DD-A-259 863 relates to the preparation of the NMMO aqueous solution: use H
2O
2The oxidation N-methylmorpholine makes reaction soln by one or more exchange columns that are full of the vinylbenzene/divinyl benzene copolymer that contains sulfonate radical, and the pH value of adding phosphoric acid regulator solution is between 8 to 5.
Shortcoming when carrying out oxidizing reaction is, the morpholine of bringing into tertiary amine as impurity that exists in process water is understood some and is oxidized to deleterious N-nitrosomorpholine, the N-nitrosomorpholine ground enrichment that can be out of favour in the NMMO-circulation.When carrying out oxidizing reaction, also can generate other nitrosamine.
For example known from EP-A-0254803, utilize N-methylmorpholine and H
2O
2Oxygenizement prepare NMMO.From the known a kind of method for preparing NMMO of DE-A-04140259, wherein for example utilize carboxylic acid halides to catch and kill primary amine and secondary amine and suppress the generation of nitrosamine.EP-A-0320690 has described the preparation of the amine oxide that is substantially free of nitrosamine: at the CO as the nitrosamine inhibitor
2/ xitix mixture exists down, utilizes peroxy oxygen to turn into making.Known from EP-A-0401503, at water and cosolvent, in the preferred carbonic ether, use H
2O
2Carry out oxidation.According to FR-A-8808039, oxygenizement is adding CO
2Condition under carry out, and according to US-A-5,216,154, the process that is oxidized to NMMO is at pure CO
2Carry out in the atmosphere.
In the prior art, or be to be unrealized to restrain the generation of nitrosamine, or be exactly that initial product by removing N-nitrosomorpholine or the use additive that slows down the N-nitrosomorpholine generating rate is achieved success.Particularly in comprising the amine oxide method of closed cycle, with various chemical, for example carboxylic acid halides, xitix or CO
2Join the purifying problem that causes process water in the technological process, because must from technological process, remove by the degraded product of the chemical generation of adding.For the number of chemical product, must consider the problem of secure context, as the danger of thermopositive reaction.Therefore, described method none is suitable for the regeneration of amine oxide method process water.
Therefore the objective of the invention is, provide a kind of from the different process water of amine oxide method the method for selective separation of morpholine, with this method basically just morpholine be separated, and NMMO and N-methylmorpholine are still stayed in the process water.
The method of the present invention's selective separation of morpholine from the aqueous solution that contains morpholine, N-methylmorpholine and NMMO, its characteristics are following steps, promptly
(A) make the aqueous solution pass through to adsorb the cationite of morpholine, until it basically again till the carrier band morpholine, and obtain being substantially free of morpholine but contain N-methylmorpholine and the elutriant of N-methylmorpholine-N-oxide compound and
(B) will be loaded with the cationite regeneration of morpholine and be reused for step (A).
The present invention is based on such knowledge, promptly apparent, cationite is with respect to N-methylmorpholine and NMMO, for morpholine higher activity is arranged, and this higher activity is enough to reach when morpholine begins to go out, N-methylmorpholine and NMMO have been eluted to higher yields, therefore make sensitive separation of morpholine become possibility.Specifically, separation is to take place like this, promptly at first adsorbs all three components, i.e. morpholine, N-methylmorpholine and NMMO on fresh cationite.When the cationite carrier band after these three components, NMMO begins to go out because the NMMO that not only comes in later can not be adsorbed again, and the morpholine that entered afterwards and N-methylmorpholine can be replaced away the NMMO that has been adsorbed.This means and in fact only contain NMMO in the elutriant this moment.
When basically all after the NMMO on the cationite is replaced, the N-methylmorpholine that the morpholine that also occurs being come in subsequently in elutriant displaces.Contain NMMO and N-methylmorpholine in the elutriant this moment.When no longer including N-methylmorpholine basically and adsorb on cationite, and the capacity of cationite has been when having exhausted, and morpholine begins to go out, and must stop wash-out and cationite is regenerated.Regeneration for example can realize with diluted mineral acid.
The cationite that uses by method of the present invention preferably has carboxylic group and/or sulfonic acid group.
Its characteristics of preferred embodiment of method of the present invention are further step, promptly
(C) elutriant that obtains in step (A) is chosen wantonly removing the laggard capable oxide treatment of anhydrating, N-methylmorpholine is oxidized to N-methylmorpholine-N-oxide compound.
This scheme of method of the present invention has guaranteed almost completely to suppress newly-generated deleterious N-nitrosomorpholine, because elutriant is substantially free of morpholine.Therefore oxidized elutriant only is contained in the N-nitrosomorpholine of low amount usually that occurs in the amine oxide method.
Advantageously carry out oxidation by peroxide oxidant.In the method for the invention, preferably adopt H
2O
2As peroxide oxidant.H
2O
2Preferably with 30-50% (weight) H
2O
2The form of the aqueous solution is used.H
2O
2Optimum amount be every mole of N-methylmorpholine 0.8-2 mole H
2O
2
Another preferred embodiment of method of the present invention is characterized in that, with the aqueous solution in oxide treatment or afterwards, is the UV-irradiation of 254nm basically with wavelength, wherein ultraviolet source low pressure mercury lamp preferably.
This scheme of method of the present invention is based on such discovery, and promptly N-nitrosomorpholine can be by with maximum strength being the UV-irradiation of 254nm and destroyed.If, therefore can reduce the contents level of this toxic substance significantly so in oxide treatment or use UV-irradiation later on, will be directed at the lower aq level of destroying N-nitrosomorpholine.
Show, preferably, at first isolate morpholine by cationite, oxidation elutriant then, because in this way, obviously shorter for destroying the required UV-irradiation time of N-nitrosomorpholine, required ultraviolet ray intensity is obviously less.If before oxidation, do not isolate morpholine, so can newly-generated N-nitrosomorpholine corresponding to morpholine content.In order to destroy these newly-generated N-nitrosomorpholines, it needs obviously long irradiation time and higher irradiation power to destroy.
Irradiation power for example can be 200-500mJ/cm
2, and depend on structure, the operating condition, particularly temperature of lamp.
The general method of known quantitative analysis nitrosamine promptly adopts the UV rayed, measures nitrite anions (D.E.G.Shuker, S.R.Tannenbaum, Anal.Chem., 1983,55 2152-2155 that generate then; M.Rhighezza, M.H.Murello, A.M.Siouffi, J.Chromat., 1987,410,145-155; J.J.Conboy, J.H.Hotchkiss, Analyst, 1989,114,155-159; B.Buchele, L.Hoffmann, J.Lang, Fresen.J.Anal.Chem., 1990,336,328-333).Yet these analytical procedures do not relate to the destruction of N-nitrosomorpholine.
For carrying out the irradiation with low-voltage lamp of the present invention, lamp can hang in the container that contains pending process fluid.But lamp also can otherwise be put.And, also can for example in the process of the continuous recirculation of solution to be illuminated, in film-UV reactor, carry out rayed.
Method of the present invention is specially adapted to handle the process water from the amine oxide method.
Another preferred version of method of the present invention has following steps, promptly
(1) make above-mentioned for example by reverse osmosis and spissated steam by can selective adsorption morpholine cationite and guarantee that pH value scope is 6.0-9.0, then
(2) will merge from the precipitation bath of cationite elutriant that obtains and the amine oxide method that contains 10-30% (weight) NMMO that purified, and
(3) will in the evaporation reaction device, handle with the elutriant that precipitation bath merges with peroxide oxidant, with with the N-methylmorpholine oxidation with concentrate, wherein, obtain spissated, aqueous NMMO and steam, NMMO turns back in the amine oxide method again, and the steam that obtains concentrated and is used for step (1).
Further illustrate the present invention with following example.Abbreviation NMOR, NMMO, NMM and the M that uses below represents N-nitrosomorpholine, N-methylmorpholine-N-oxide compound, N-methylmorpholine and morpholine.
Example 1
Making the process water from the amine oxide method, exactly is the retentate of reverse osmosis, and (the polyacrylic acid skeleton has carboxyl as functional group by weakly acidic cationite; Dowexcc-2; The producer: The Dow Chemical Company).The pH of this retentate is 9.9, and is made up of following: NMMO:1661ppm NMM: 2377ppm M: 1376ppm
At diameter is that 2.5cm and height are use 30ml cationite in the post of about 5.5cm.Make retentate pass through cationite with the speed of 4 bed volumes per hour.Collect an elutriant every 5 bed volumes, and measure the concentration of pH-value and NMMO, NMM and M at every turn subsequently.After 10 bed volumes, cationite begins swelling, and swelling lasts till reinforced end continuously and reach 150% behind 200 bed volumes.
The concentration of NMMO, NMM and M (ppm) is by high-pressure liquid chromatography (post: 150 * 4 millimeters of Hypersil Si; 50 ℃; Eluent: 52% acetonitrile far UV, FisionsScientific Equipment, number A/0627/17; The KH of 48%10 mmoles
2PO
4(Merck, number 4873) is adjusted to pH6.7 with NaOH; 1 ml/min of constant gradient; Detector: UV192nm).Quantitatively all realizing of each component by 3 calibrations of external standard.Following table has provided the result.
Table bed volume NMMO NMM M pH starting point 1,661 2,377 1,376 9.95 1 n.b. n.b. 4.010 1 n.b. n.b. 3.920 332 2 n.b. 5.130 2,350 1 n.b. 5.840 2,409 241 n.b. 7.450 2,064 276 2 7.360 2,026 1,210 3 8.170 1,943 1,517 5 8.180 1,850 2,516 6 8.490 1,805 2,736 6 8.4100 1,671 3,461 5 8.5110 1,632 4,031 5 8.6120 1,594 4,050 6 8.6130 1,594 3,919 6 8.6140 1,596 4,132 6 8.6150 1,597 4,063 7 8.6160 1,596 3,939 13 8.6170 1,588 4,060 85 8.6180 1,605 3,441 459 8.8190 1,625 2,723 1,422 9.3200 1,620 2,390 1,875 9.3210 1,646 2,390 1,748 9.2
N.b.=can not measure
Known to from table, M can significantly separate with NMM and NMMO:
When just beginning, all three components, no matter NMMO, NMM or M all be detained to live by cationite, and pH drop to 4.0 by 9.9 in other words.
Since the 20th bed volume NMMO wash-out, meanwhile NMM and M are detained, and like this up to the 40th bed volume, elutriant all only contains NMMO.PH is raised to 5.8.Perhaps, the wash-out of NMMO is to cause NMM and the squeezing of M that the NMMO that adsorbed by cationite is added successively.
Since the 40th bed volume, NMM is also by wash-out, and meanwhile M continues to be detained.PH is raised to about 8-9.Obviously, the NMM that is adsorbed is squeezed from cationite by the M that adds successively.
Unexpectedly be that M just begins by wash-out from about the 170th bed volume.Like this, to the NMMO and the NMM that have reclaimed at this moment at least 85% (weight).From this moment, pH rises again, and is raised to about 9.3.Therefore behind 170 bed volumes, cationite is fully by morpholine load, and must regenerate.
The elutriant of collecting until the 170th bed volume is substantially free of M, and can carry out oxide treatment to obtain NMMO.
Example 2
For NMM is oxidized to NMMO, mixing concentration to every liter of aqueous solution that contains 25 microgram NMOR, 2530 milligrams of NMMO, 3923 milligrams of NMM and 30 milligrams of M is 30% H
2O
2(mole NMM/ mole H
2O
2=1/1.2), and in ultraviolet reactor (model is Katadyn UV-Strahler EK-36, number 79000 with low pressure mercury lamp; Producer: Katadyn) irradiation (wavelength: 254 millimicrons).The temperature of process water is 50 ℃.
The concentration of NMOR is by high-pressure liquid chromatography (post: 250 * 4 millimeters of Hypersil ODS; 50 ℃; Eluent: A=0.6% acetonitrile; B=49.7%H
2O; Gradient 1 ml/min; 10 minutes-100%A; 7 minutes-100%B; Detector: ultraviolet 238nm) measure.In first 90 minutes, the concentration of NMOR rises to 45 micrograms per litre, and this will be owing to the rapid reaction of the M in solution.The concentration of NMOR obviously descends subsequently.No longer determine NMOR after 6 hours.
After total oxidation time reached 20 hours, solution contained 5386 milligrams of NMMO/ liters, and this is equivalent to 62% of theoretical yield.
Claims (8)
1. the method for selective separation of morpholine from the aqueous solution that contains morpholine, N-methylmorpholine and N-methylmorpholine-N-oxide compound is characterized in that following steps:
(A) make the aqueous solution pass through to adsorb the cationite of morpholine, until it basically again till the carrier band morpholine, and obtain being substantially free of morpholine but contain N-methylmorpholine and the elutriant of N-methylmorpholine-N-oxide compound and
(B) carrier band there is the cationite regeneration of morpholine and be reused for step (A).
2. according to the method for claim 1, it is characterized in that cationite has carboxylic group.
3. according to the method for claim 1, it is characterized in that cationite has sulfonic acid group.
4. according to the method for one of claim 1 to 3, it is characterized in that step in addition, promptly
(C) elutriant that obtains in step (A) is chosen wantonly removing the laggard capable oxide treatment of anhydrating, N-methylmorpholine is oxidized to N-methylmorpholine-N-oxide compound.
5. according to the method for claim 4, it is characterized in that, carry out oxidation with peroxide oxidant.
6. according to the method for claim 4, it is characterized in that, with the aqueous solution in oxide treatment or be the UV-irradiation of 254nm afterwards basically with wavelength.
7. according to the method for claim 6, it is characterized in that UV-light is from low pressure mercury lamp.
8. according to the method for one of claim 1 to 3, it is characterized in that, contain the aqueous solution of morpholine, N-methylmorpholine and N-methylmorpholine-N-oxide compound with the process water conduct that derives from the amine oxide method.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| AT140395A AT403297B (en) | 1995-08-18 | 1995-08-18 | METHOD FOR SELECTIVE SEPARATION OF MORPHOLINE |
| ATA1403/95 | 1995-08-18 | ||
| ATA1403/1995 | 1995-08-18 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1165514A CN1165514A (en) | 1997-11-19 |
| CN1071750C true CN1071750C (en) | 2001-09-26 |
Family
ID=3513141
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN96191128A Expired - Fee Related CN1071750C (en) | 1995-08-18 | 1996-08-16 | Process for the selective separation of morpholine |
Country Status (9)
| Country | Link |
|---|---|
| EP (1) | EP0783497A1 (en) |
| JP (1) | JPH10508318A (en) |
| CN (1) | CN1071750C (en) |
| AT (1) | AT403297B (en) |
| AU (1) | AU700207B2 (en) |
| BR (1) | BR9606585A (en) |
| CA (1) | CA2202153A1 (en) |
| NO (1) | NO310572B1 (en) |
| WO (1) | WO1997007108A1 (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE19842556C2 (en) * | 1998-09-17 | 2003-02-06 | Alceru Schwarza Gmbh | Process for the production of cellulosic moldings |
| CN111801319A (en) * | 2018-03-15 | 2020-10-20 | 巴斯夫欧洲公司 | Process for removing methoxyethanol from a mixture comprising methoxyethanol and morpholine |
| CN110563669A (en) * | 2019-10-09 | 2019-12-13 | 四川鸿鹏新材料有限公司 | Method and device for improving morpholine purity |
| CN112480035A (en) * | 2020-10-28 | 2021-03-12 | 华茂伟业绿色科技股份有限公司 | N-methylmorpholine and purification method thereof, methylmorpholine oxide and preparation method thereof |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0448924A1 (en) * | 1990-03-28 | 1991-10-02 | Lenzing Aktiengesellschaft | Process for separating water from a diluted aqueous solution of N-methylmorpholine-N-oxide, N-methylmorpholine and/or morpholine |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DD254199B5 (en) * | 1986-12-04 | 1994-01-05 | Thueringische Faser Ag Schwarz | PROCESS FOR CLEANING WAFERRIGER N-METHYLMORPHOLIN N-OXYD SOLUTIONS |
| DD259863A1 (en) * | 1987-04-06 | 1988-09-07 | Schwarza Chemiefaser | METHOD FOR PRODUCING WAFERRIGER, PURE N-METHYLMORPHOLIN N-OXIDE SOLUTIONS |
| DD274435B5 (en) * | 1988-08-02 | 1996-10-31 | Thueringisches Inst Textil | Process for the recovery of N-methylmorpholine-N-oxide |
| AT393114B (en) * | 1989-06-08 | 1991-08-26 | Chemiefaser Lenzing Ag | METHOD FOR SEPARATING AMINES |
-
1995
- 1995-08-18 AT AT140395A patent/AT403297B/en not_active IP Right Cessation
-
1996
- 1996-08-16 CN CN96191128A patent/CN1071750C/en not_active Expired - Fee Related
- 1996-08-16 BR BR9606585A patent/BR9606585A/en not_active Application Discontinuation
- 1996-08-16 JP JP9508733A patent/JPH10508318A/en not_active Ceased
- 1996-08-16 AU AU66954/96A patent/AU700207B2/en not_active Ceased
- 1996-08-16 WO PCT/AT1996/000146 patent/WO1997007108A1/en not_active Application Discontinuation
- 1996-08-16 CA CA 2202153 patent/CA2202153A1/en not_active Abandoned
- 1996-08-16 EP EP96926960A patent/EP0783497A1/en not_active Ceased
-
1997
- 1997-04-17 NO NO19971753A patent/NO310572B1/en not_active IP Right Cessation
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0448924A1 (en) * | 1990-03-28 | 1991-10-02 | Lenzing Aktiengesellschaft | Process for separating water from a diluted aqueous solution of N-methylmorpholine-N-oxide, N-methylmorpholine and/or morpholine |
Also Published As
| Publication number | Publication date |
|---|---|
| AT403297B (en) | 1997-12-29 |
| AU700207B2 (en) | 1998-12-24 |
| NO310572B1 (en) | 2001-07-23 |
| AU6695496A (en) | 1997-03-12 |
| JPH10508318A (en) | 1998-08-18 |
| NO971753L (en) | 1997-04-17 |
| CN1165514A (en) | 1997-11-19 |
| WO1997007108A1 (en) | 1997-02-27 |
| NO971753D0 (en) | 1997-04-17 |
| ATA140395A (en) | 1997-05-15 |
| BR9606585A (en) | 1997-10-28 |
| CA2202153A1 (en) | 1997-02-27 |
| EP0783497A1 (en) | 1997-07-16 |
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