JPS6210221B2 - - Google Patents
Info
- Publication number
- JPS6210221B2 JPS6210221B2 JP53080916A JP8091678A JPS6210221B2 JP S6210221 B2 JPS6210221 B2 JP S6210221B2 JP 53080916 A JP53080916 A JP 53080916A JP 8091678 A JP8091678 A JP 8091678A JP S6210221 B2 JPS6210221 B2 JP S6210221B2
- Authority
- JP
- Japan
- Prior art keywords
- alkylamide
- aqueous solution
- extraction
- chloride
- polymerization
- 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
Links
- 239000007864 aqueous solution Substances 0.000 claims description 52
- 238000000034 method Methods 0.000 claims description 34
- 229910001385 heavy metal Inorganic materials 0.000 claims description 29
- YMWUJEATGCHHMB-UHFFFAOYSA-N Dichloromethane Chemical compound ClCCl YMWUJEATGCHHMB-UHFFFAOYSA-N 0.000 claims description 27
- 229910001504 inorganic chloride Inorganic materials 0.000 claims description 26
- 150000002500 ions Chemical class 0.000 claims description 22
- 239000000243 solution Substances 0.000 claims description 17
- HEDRZPFGACZZDS-UHFFFAOYSA-N Chloroform Chemical compound ClC(Cl)Cl HEDRZPFGACZZDS-UHFFFAOYSA-N 0.000 claims description 8
- UBOXGVDOUJQMTN-UHFFFAOYSA-N 1,1,2-trichloroethane Chemical compound ClCC(Cl)Cl UBOXGVDOUJQMTN-UHFFFAOYSA-N 0.000 claims description 4
- 150000008282 halocarbons Chemical class 0.000 claims description 4
- WSLDOOZREJYCGB-UHFFFAOYSA-N 1,2-Dichloroethane Chemical compound ClCCCl WSLDOOZREJYCGB-UHFFFAOYSA-N 0.000 claims description 3
- 230000000737 periodic effect Effects 0.000 claims description 2
- 229910052751 metal Inorganic materials 0.000 claims 1
- 239000002184 metal Substances 0.000 claims 1
- 238000000605 extraction Methods 0.000 description 47
- 238000006116 polymerization reaction Methods 0.000 description 30
- FXHOOIRPVKKKFG-UHFFFAOYSA-N N,N-Dimethylacetamide Chemical compound CN(C)C(C)=O FXHOOIRPVKKKFG-UHFFFAOYSA-N 0.000 description 22
- 229920000642 polymer Polymers 0.000 description 22
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 20
- 239000012071 phase Substances 0.000 description 20
- SECXISVLQFMRJM-UHFFFAOYSA-N N-Methylpyrrolidone Chemical compound CN1CCCC1=O SECXISVLQFMRJM-UHFFFAOYSA-N 0.000 description 18
- 239000007787 solid Substances 0.000 description 17
- 239000007788 liquid Substances 0.000 description 16
- KWGKDLIKAYFUFQ-UHFFFAOYSA-M lithium chloride Chemical compound [Li+].[Cl-] KWGKDLIKAYFUFQ-UHFFFAOYSA-M 0.000 description 14
- 238000011084 recovery Methods 0.000 description 13
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 12
- -1 benzene Chemical compound 0.000 description 12
- 239000000463 material Substances 0.000 description 11
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 11
- 239000000126 substance Substances 0.000 description 10
- 229910052742 iron Inorganic materials 0.000 description 9
- 238000004821 distillation Methods 0.000 description 8
- 238000000465 moulding Methods 0.000 description 8
- 238000003756 stirring Methods 0.000 description 8
- UXVMQQNJUSDDNG-UHFFFAOYSA-L Calcium chloride Chemical compound [Cl-].[Cl-].[Ca+2] UXVMQQNJUSDDNG-UHFFFAOYSA-L 0.000 description 7
- 239000001110 calcium chloride Substances 0.000 description 7
- 229910001628 calcium chloride Inorganic materials 0.000 description 7
- 239000002904 solvent Substances 0.000 description 7
- WMFOQBRAJBCJND-UHFFFAOYSA-M Lithium hydroxide Chemical compound [Li+].[OH-] WMFOQBRAJBCJND-UHFFFAOYSA-M 0.000 description 6
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 6
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 6
- 239000003795 chemical substances by application Substances 0.000 description 6
- 230000000052 comparative effect Effects 0.000 description 6
- 230000000694 effects Effects 0.000 description 6
- 239000012535 impurity Substances 0.000 description 6
- 239000002351 wastewater Substances 0.000 description 6
- 229910001430 chromium ion Inorganic materials 0.000 description 5
- 238000000354 decomposition reaction Methods 0.000 description 5
- 229910001437 manganese ion Inorganic materials 0.000 description 5
- 239000000203 mixture Substances 0.000 description 5
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 4
- 238000007667 floating Methods 0.000 description 4
- 239000011521 glass Substances 0.000 description 4
- 239000000843 powder Substances 0.000 description 4
- UHOVQNZJYSORNB-UHFFFAOYSA-N Benzene Chemical compound C1=CC=CC=C1 UHOVQNZJYSORNB-UHFFFAOYSA-N 0.000 description 3
- VEQPNABPJHWNSG-UHFFFAOYSA-N Nickel(2+) Chemical compound [Ni+2] VEQPNABPJHWNSG-UHFFFAOYSA-N 0.000 description 3
- 239000002253 acid Substances 0.000 description 3
- JFDZBHWFFUWGJE-UHFFFAOYSA-N benzonitrile Chemical compound N#CC1=CC=CC=C1 JFDZBHWFFUWGJE-UHFFFAOYSA-N 0.000 description 3
- 239000006227 byproduct Substances 0.000 description 3
- 238000005345 coagulation Methods 0.000 description 3
- 230000015271 coagulation Effects 0.000 description 3
- 238000004817 gas chromatography Methods 0.000 description 3
- QZUPTXGVPYNUIT-UHFFFAOYSA-N isophthalamide Chemical compound NC(=O)C1=CC=CC(C(N)=O)=C1 QZUPTXGVPYNUIT-UHFFFAOYSA-N 0.000 description 3
- 229910052759 nickel Inorganic materials 0.000 description 3
- 229910001453 nickel ion Inorganic materials 0.000 description 3
- 239000000047 product Substances 0.000 description 3
- 238000000926 separation method Methods 0.000 description 3
- MHSKRLJMQQNJNC-UHFFFAOYSA-N terephthalamide Chemical compound NC(=O)C1=CC=C(C(N)=O)C=C1 MHSKRLJMQQNJNC-UHFFFAOYSA-N 0.000 description 3
- WZCQRUWWHSTZEM-UHFFFAOYSA-N 1,3-phenylenediamine Chemical compound NC1=CC=CC(N)=C1 WZCQRUWWHSTZEM-UHFFFAOYSA-N 0.000 description 2
- CBCKQZAAMUWICA-UHFFFAOYSA-N 1,4-phenylenediamine Chemical compound NC1=CC=C(N)C=C1 CBCKQZAAMUWICA-UHFFFAOYSA-N 0.000 description 2
- NLXLAEXVIDQMFP-UHFFFAOYSA-N Ammonia chloride Chemical compound [NH4+].[Cl-] NLXLAEXVIDQMFP-UHFFFAOYSA-N 0.000 description 2
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 description 2
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 2
- TWRXJAOTZQYOKJ-UHFFFAOYSA-L Magnesium chloride Chemical compound [Mg+2].[Cl-].[Cl-] TWRXJAOTZQYOKJ-UHFFFAOYSA-L 0.000 description 2
- OFOBLEOULBTSOW-UHFFFAOYSA-N Malonic acid Chemical compound OC(=O)CC(O)=O OFOBLEOULBTSOW-UHFFFAOYSA-N 0.000 description 2
- 239000004952 Polyamide Substances 0.000 description 2
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 description 2
- 230000002378 acidificating effect Effects 0.000 description 2
- 150000007513 acids Chemical class 0.000 description 2
- FDQSRULYDNDXQB-UHFFFAOYSA-N benzene-1,3-dicarbonyl chloride Chemical compound ClC(=O)C1=CC=CC(C(Cl)=O)=C1 FDQSRULYDNDXQB-UHFFFAOYSA-N 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 2
- 150000001805 chlorine compounds Chemical class 0.000 description 2
- MVPPADPHJFYWMZ-UHFFFAOYSA-N chlorobenzene Chemical compound ClC1=CC=CC=C1 MVPPADPHJFYWMZ-UHFFFAOYSA-N 0.000 description 2
- 238000011109 contamination Methods 0.000 description 2
- 238000005260 corrosion Methods 0.000 description 2
- 230000007797 corrosion Effects 0.000 description 2
- 238000002474 experimental method Methods 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-M hydroxide Chemical compound [OH-] XLYOFNOQVPJJNP-UHFFFAOYSA-M 0.000 description 2
- 238000006386 neutralization reaction Methods 0.000 description 2
- 229920002647 polyamide Polymers 0.000 description 2
- JIAARYAFYJHUJI-UHFFFAOYSA-L zinc dichloride Chemical compound [Cl-].[Cl-].[Zn+2] JIAARYAFYJHUJI-UHFFFAOYSA-L 0.000 description 2
- AVQQQNCBBIEMEU-UHFFFAOYSA-N 1,1,3,3-tetramethylurea Chemical compound CN(C)C(=O)N(C)C AVQQQNCBBIEMEU-UHFFFAOYSA-N 0.000 description 1
- NWUYHJFMYQTDRP-UHFFFAOYSA-N 1,2-bis(ethenyl)benzene;1-ethenyl-2-ethylbenzene;styrene Chemical compound C=CC1=CC=CC=C1.CCC1=CC=CC=C1C=C.C=CC1=CC=CC=C1C=C NWUYHJFMYQTDRP-UHFFFAOYSA-N 0.000 description 1
- KYWXRBNOYGGPIZ-UHFFFAOYSA-N 1-morpholin-4-ylethanone Chemical compound CC(=O)N1CCOCC1 KYWXRBNOYGGPIZ-UHFFFAOYSA-N 0.000 description 1
- LNWWQYYLZVZXKS-UHFFFAOYSA-N 1-pyrrolidin-1-ylethanone Chemical compound CC(=O)N1CCCC1 LNWWQYYLZVZXKS-UHFFFAOYSA-N 0.000 description 1
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 description 1
- WAEMQWOKJMHJLA-UHFFFAOYSA-N Manganese(2+) Chemical compound [Mn+2] WAEMQWOKJMHJLA-UHFFFAOYSA-N 0.000 description 1
- AMQJEAYHLZJPGS-UHFFFAOYSA-N N-Pentanol Chemical compound CCCCCO AMQJEAYHLZJPGS-UHFFFAOYSA-N 0.000 description 1
- 239000004962 Polyamide-imide Substances 0.000 description 1
- 239000004642 Polyimide Substances 0.000 description 1
- 239000004743 Polypropylene Substances 0.000 description 1
- 239000004809 Teflon Substances 0.000 description 1
- 229920006362 Teflon® Polymers 0.000 description 1
- BTGRAWJCKBQKAO-UHFFFAOYSA-N adiponitrile Chemical compound N#CCCCCC#N BTGRAWJCKBQKAO-UHFFFAOYSA-N 0.000 description 1
- 150000001298 alcohols Chemical class 0.000 description 1
- 235000019270 ammonium chloride Nutrition 0.000 description 1
- 239000008346 aqueous phase Substances 0.000 description 1
- 239000004760 aramid Substances 0.000 description 1
- 150000004984 aromatic diamines Chemical class 0.000 description 1
- 229920003235 aromatic polyamide Polymers 0.000 description 1
- 125000003118 aryl group Chemical group 0.000 description 1
- ALHNLFMSAXZKRC-UHFFFAOYSA-N benzene-1,4-dicarbohydrazide Chemical compound NNC(=O)C1=CC=C(C(=O)NN)C=C1 ALHNLFMSAXZKRC-UHFFFAOYSA-N 0.000 description 1
- AXCZMVOFGPJBDE-UHFFFAOYSA-L calcium dihydroxide Chemical compound [OH-].[OH-].[Ca+2] AXCZMVOFGPJBDE-UHFFFAOYSA-L 0.000 description 1
- 239000000920 calcium hydroxide Substances 0.000 description 1
- 229910001861 calcium hydroxide Inorganic materials 0.000 description 1
- 239000013522 chelant Substances 0.000 description 1
- 239000011651 chromium Substances 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 239000012141 concentrate Substances 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 230000002596 correlated effect Effects 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- WYACBZDAHNBPPB-UHFFFAOYSA-N diethyl oxalate Chemical compound CCOC(=O)C(=O)OCC WYACBZDAHNBPPB-UHFFFAOYSA-N 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 239000004744 fabric Substances 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 239000000835 fiber Substances 0.000 description 1
- 229930195733 hydrocarbon Natural products 0.000 description 1
- 150000002430 hydrocarbons Chemical class 0.000 description 1
- 230000007062 hydrolysis Effects 0.000 description 1
- 238000006460 hydrolysis reaction Methods 0.000 description 1
- 230000002401 inhibitory effect Effects 0.000 description 1
- 229910001867 inorganic solvent Inorganic materials 0.000 description 1
- 239000003049 inorganic solvent Substances 0.000 description 1
- 238000011835 investigation Methods 0.000 description 1
- 239000003456 ion exchange resin Substances 0.000 description 1
- 229920003303 ion-exchange polymer Polymers 0.000 description 1
- 238000000622 liquid--liquid extraction Methods 0.000 description 1
- 229910052744 lithium Inorganic materials 0.000 description 1
- 230000007774 longterm Effects 0.000 description 1
- 229910001629 magnesium chloride Inorganic materials 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000004949 mass spectrometry Methods 0.000 description 1
- 229910021645 metal ion Inorganic materials 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 230000007935 neutral effect Effects 0.000 description 1
- 230000003472 neutralizing effect Effects 0.000 description 1
- 239000011368 organic material Substances 0.000 description 1
- 229920000620 organic polymer Polymers 0.000 description 1
- 239000003960 organic solvent Substances 0.000 description 1
- 229920002312 polyamide-imide Polymers 0.000 description 1
- 229920001721 polyimide Polymers 0.000 description 1
- 230000000379 polymerizing effect Effects 0.000 description 1
- 229920001155 polypropylene Polymers 0.000 description 1
- 229910052573 porcelain Inorganic materials 0.000 description 1
- 239000002244 precipitate Substances 0.000 description 1
- 238000001556 precipitation Methods 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 239000011347 resin Substances 0.000 description 1
- 229920005989 resin Polymers 0.000 description 1
- 239000002893 slag Substances 0.000 description 1
- 239000002002 slurry Substances 0.000 description 1
- 239000011780 sodium chloride Substances 0.000 description 1
- 238000000638 solvent extraction Methods 0.000 description 1
- 238000002798 spectrophotometry method Methods 0.000 description 1
- 239000003381 stabilizer Substances 0.000 description 1
- 239000011550 stock solution Substances 0.000 description 1
- 238000003860 storage Methods 0.000 description 1
- LXEJRKJRKIFVNY-UHFFFAOYSA-N terephthaloyl chloride Chemical compound ClC(=O)C1=CC=C(C(Cl)=O)C=C1 LXEJRKJRKIFVNY-UHFFFAOYSA-N 0.000 description 1
- 238000002166 wet spinning Methods 0.000 description 1
- 239000011592 zinc chloride Substances 0.000 description 1
- 235000005074 zinc chloride Nutrition 0.000 description 1
Landscapes
- Pyrrole Compounds (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Description
本発明は無機塩化物及び重金属イオンを含有す
るN−アルキルアミド水溶液から、N−アルキル
アミドを回収する方法に関する。その目的は無機
塩化物及び重金属イオンを含有するN−アルキル
アミド水溶液から、N−アルキルアミドを安定し
た工程で、安価に、収率よく、かつ高純度で回収
する方法を提供することにある。
近年、業界においては、耐熱性、難燃性、高強
力性、耐薬品性及び寸法安定性を有する有機素材
への要望が強く、そのために芳香族ポリアミド、
ポリアミドヒドラジド、ポリアミドイミド、ポリ
イミド等のいわゆる有機耐熱性ポリマーの製造が
盛んに行なわれている。これらはすでに繊維、フ
イルム、紙、テープ等に成形され各種工業用品と
して利用されてきている。
しかし、これらのポリマーは、極めて難溶性で
あつて、通常の安価な有機溶剤には溶解しない。
ポリマーの重合や成形のためには、N・N−ジメ
チルアセトアミド、N−メチルピロリドンに代表
されるいわゆるN−アルキルアミドといわれる高
価な溶剤と、溶剤助剤としての塩化リチウムや塩
化カルシウム等の無機塩化物の混合物が使用され
ている。
この無機塩化物を含むN−アルキルアミドを用
いて重合されたポリマーや、成形された成形物は
通常水によつて洗浄され、単離される。一方、N
−アルキルアミドは無機塩化物と共に、水溶液の
形でポリマーや成形物から分離される。そして、
N−アルキルアミドは高価であるが故に、回収し
て再使用する必要があり、この水溶液からいかに
収率よく、安価に、高純度のN−アルキルアミド
を回収するかということが、この工業の成効の鍵
を握るものとされている。
そして、ポリマーの成形に用いたN−アルキル
アミドと無機塩化物(塩化カルシウム)の水溶液
からN−アルキルアミドを、ジクロルメタン他の
抽剤で抽出回収する方法は公知である(特公−昭
48−23415、特公−昭49−48432号各公報)。
しかし、芳香族ポリアミドを得るための芳香族
ジカルボン酸クロライドと芳香族ジアミンの反応
の如く、重合に用いられ、常法に従つて、重合時
に副生する塩酸を中和して水溶液となつたN−ア
ルキルアミドを、この方法で抽出回収するに際し
ては、回収して得られるN−アルキルアミドの品
質上においても、抽出回収する工程上においても
問題を有している事実が見い出された。
即ち、回収したN−アルキルアミドの品質上の
問題とは、再度この溶剤を使用して重合を実施す
る場合、得られるポリマーの重合度が十分なもの
ではなくなるという現象である。この原因は定か
ではないが、回収したN−アルキルアミドに重合
を阻害する不純物が含有されているものと推定さ
れ、この不純物の同定をガスクロマトグラフイー
及びマススペクトルスコピー等の手段で検討して
いるが、現在未だ解明されるには至つていない。
また、抽出回収における工程上の問題とは、抽
出操作時に水溶液と抽剤が接触することによつて
生じる固形物(いわゆる「ノロ」)によるもので
ある。本発明者らの究明によれば、この固形物は
N−アルキルアミド水溶液中に混入する重金属イ
オンによるものであり、N−アルキルアミドある
いはその分解物が、重金属、無機物と何らかの形
で結合したものであると推定された。この固形物
は、抽出操作時に発生し、抽出装置内に付着し液
−液抽出の接触面積を減少させ徐々に抽出率を低
下させ、遂には抽出操作を不可能に至らしめる。
又、この固形物は浮遊性をも有しており、抽廃水
や抽出相中に混入し、抽出工程以降の回収工程に
おいても、熱交換器等に付着して熱伝導を悪くす
る等の各種トラブルを引きおこす。
このトラブルの原因となる重金属イオンの混入
は、ある種の無機塩化物に元来含まれているも
の、及び重合において発生する塩酸による装置材
料の腐蝕によるものである。
周知の如く塩酸は、一般に装置材料として用い
られる鉄材、SUS材を腐蝕し、全く腐蝕を無くす
るためには非常に高価な材料を使用するか、テフ
ロンやガラスのライニング、コーテイング等の処
置を施さなければならない。しかし、このような
材質で、これらの化合物が接触するすべての装置
を作ることは経済的に困難であり、さらに装置に
要求される機械的強度、及び装置製作時の加工性
から物理的に不可能な場合がほとんどであつて、
重合の溶剤として用いたN−アルキルアミドの回
収すべき水溶液中に、重金属イオンが混入するこ
とは不可避の事実である。
本発明者らは、このような無機塩化物及び重金
属イオンを含むN−アルキルアミド水溶液からの
N−アルキルアミドの抽出回収において、該抽出
操作を円滑に行ない得、高純度で収率よく回収で
きる改良方法を開発すべく検討した結果、該水溶
液を特定のPH域に調整することによつて、抽出時
の固形物の発生を防止することに成功した。さら
に、該水溶液を特定のPH域において抽出操作を行
うことにより、回収されたN−アルキルアミド中
の重合阻害不純物を、事実上重合に関与しない量
まで減少させることが可能であり、回収するN−
アルキルアミドの品質上の問題も一挙に解決でき
ることを見い出した。本発明は上記知見に基いて
完成され、所期の目的を達成するに至つたもので
ある。
即ち、本発明は重量で1〜50%の無機塩化物と
5ppm以上の重金属イオンを含有するN−アルキ
ルアミド水溶液から、N−アルキルアミドを回収
するにあたり、該水溶液のPH2.5〜5.5に調整して
抽剤で抽出することよりなるN−アルキルアミド
の抽出回収方法である。
従来、N−アルキルアミド水溶液を抽出するに
際して該水溶液を酸性に保つということは、N−
アルキルアミドの加水分解に対する安定性から好
ましくないと考えられていたものである。しかる
に本発明方法において、この水溶液を特定のPH域
に調整し、抽出を行なうことにより、安定した工
程で、安価に収率よく、かつ高純度のN−アルキ
ルアミドの回収が可能になつたことは驚くべきこ
とである。
本発明によつて見い出されたPH域において、な
ぜ、従来の技術で発生した固形物が発生せず、重
合を阻害する不純物が、抽出相から回収したN−
アルキルアミドに含まれなくなつたかは明確では
ないが、いずれもこれらのものが水溶液のPHによ
つて抽出率が変化することによるものであろうと
推定される。
本発明は、重合に用いられたN−アルキルアミ
ド水溶液のみならず、成形に用いられたN−アル
キルアミド水溶液においても適用することができ
る。即ち、長期間成形の凝固液として用いられた
無機塩化物を含むN−アルキルアミドは無機塩化
物の腐蝕性ゆえに、装置機材を浸蝕し、重金属イ
オンを無視できぬ量含有しており、さらにN−ア
ルキルアミドの分解等により、重合時に反応を阻
害する不純物をも含有していることによるもので
あり、このような場合には本発明の効果が発揮さ
れる。
本発明でいうN−アルキルアミドとは、N・N
−ジメチルアセトアミド、N−メチルピロリド
ン、テトラメチルウレア、N−アセチルピロリジ
ン、N−アセチルモルホリン等の溶剤を云い、こ
れらは一種単独であるいは二種以上混合されて用
いられる。
また本発明においてN−アルキルアミド水溶液
に含有される無機塩化物とは、N−アルキルアミ
ドを用いてポリマーを重合する、あるいは成形す
るに際し共存させることによつて有利であると知
られている塩化リチウム、塩化マグネシウム、塩
化カルシウム、塩化亜鉛等の重合あるいは成形時
に添加された無機塩化物を云い、またジカルボン
酸クロライドを用いた重合時に副生する塩酸を中
和することによつて生じる上記の無機塩化物及び
塩化ナトリウム、塩化アンモニウム等の副生無機
塩化物も含まれる。これらの無機塩化物は一種単
独でも二種以上混合されても本発明の効果をそこ
なうものではなく、水溶液中の濃度が重量で1〜
50%の場合に本発明に適用される。
本発明ではN−アルキルアミド水溶液のPHは
2.5〜5.5の任意の値がとられてよい。ただし、本
発明者らによる検討検果、安定した工程でN−ア
ルキルアミドを回収するために適するPH範囲の上
限が水溶液に含有される重金属イオンの濃度と相
関があることが判明した。即ち本発明でいう重金
属イオンとは一般的な装置材料として使用されて
いる各種鉄材、SUS材を構成する元素で、周期律
表第4周期の第、、族を構成する元素のう
ちの金属イオンを言い、鉄、ニツケル、クロム、
マンガンの各イオンが含まれ、二種以上の混合物
でもよいが、この重金属イオンの総和が5ppm以
上になると抽出時に固形物の析出がみられ、これ
を防止するためには水溶液のPH6.0以下にするこ
とが必要であつた。ちなみに重金属イオンが
50ppmの場合に適するPH値上限は5.2であり、重
金属イオンの濃度によつてこれらの上限値以下の
PH値をとることによつて工程的トラブルを回避す
ることができる。
一方、重合を阻害する不純物の回収溶剤への混
入を防止する事は、水溶液のPHを2.5〜5.5に調整
することによつて達成される。さらに好ましいPH
領域は3.0〜5.0である。
N−アルキルアミド水溶液のPHが2.5〜5.5で抽
出を受けるための方法は任意の方法が採られても
よい。そして容易に採用される方法は無機塩化
物、重金属イオンを含むN−アルキルアミド水溶
液の抽出操作を実施する前に、PHを本発明領域に
調整する方法である。即ち、中和水溶液に塩酸等
の酸類を微量加えてPHを調整する方法である。ま
たN−アルキルアミドを用いて重合する際に塩酸
が副生するような場合には、すでに中和した水溶
液に酸類を添加して調整する上述の方法の他、完
全に中和することなく、副生する塩酸の一部のみ
中和するか、あるいは、全く中和操作を行なわず
にPHを本発明領域に保つ方法等が任意にとられて
よい。また場合によつては抽剤に酸類を加えてお
き抽出時の水溶液相のPHを実質的に2.5〜5.5にす
る方法が採られてもよく、抽剤自体が酸性で安定
なものについては抽剤の分解を防止する意味から
も推奨される。
本発明の抽出に用いる抽剤は、通常の水溶液か
らのN−アルキルアミドの抽出に用いる抽剤が用
いられてよく、ジクロメタン、クロルベンゼン等
のハロゲン化炭化水素、ベンゼン等の炭化水素、
アミールアルコール等の高級アルコール、蓚酸ジ
エチル等のエステル化合物、アジポニトリル、ベ
ンゾニトリル等のニトリル化合物が知られてい
る。本発明者らの検討によれば、本発明の抽剤と
して好ましいのはハロゲン化炭化水素であり、さ
らに好ましくはジクロルメタン、1・2−ジクロ
ルエタン、クロロホルム、1・1・2−トリクロ
ルエタンであり、これらは一種のみあるいは二種
以上混合して用いられる。これらのハロゲン化炭
化水素は抽出率において秀れているばかりでな
く、本発明の特徴である酸性水溶液との接触によ
り抽剤自体の分解が抑制され好結果をもたらすこ
とも判明した。
この抽剤を用いるN−アルキルアミドの抽出条
件、即ち抽出温度、抽剤量等はN−アルキルアミ
ドの種類、水溶液中の濃度、及び抽剤の種類によ
つて任意に選択しうる。
またこの抽出に用いる装置も特に制限されず、
連続式、回分式を問わず、回転翼内臓式塔、充填
式塔、棚段式塔あるいは遠心力を利用した抽出装
置、邪魔板を利用した抽出装置、通常の撹拌機能
を有する混合槽を用いる抽出装置等が有効に利用
できる。
また本発明に従つて抽出された抽出相から、N
−アルキルアミドを回収するための方法は制限さ
れるものではなく、一般のN−アルキルアミドと
抽剤を分離するための各種の方法がとられてよ
い。容易な方法は通常の分離蒸留であり、連続
式、回分式を問わず用いられる。回収すべきN−
アルキルアミドの純度は再使用される条件にあわ
せて任意に選択できる。しかも本発明による場合
は固形物の混入がないために蒸留残渣として除去
すべきN−アルキルアミドの量が減少し、N−ア
ルキルアミドの回収率を飛躍的に増大させること
ができる。さらには蒸留中における固形物の存在
がないために、熱交換器への固形物付着による熱
伝導の低下がみられず、またフラツデイング現象
も生じないために、安定な品質の回収N−アルキ
ルアミドを得ることができる。
本発明を実施することにより発生する抽廃水の
処理については任意の方法が採られてよい。即
ち、本発明により得られる抽廃水は酸性を示し、
中和緩放流するも、あるいは含まれる無機塩化物
を回収するも任意であり、無機塩化物の原価と、
回収に要する費用と決定される。通常、無機塩化
物の濃度が高ければ回収されるのが有利であり、
このための方法も自由に選ばれてよい。即ち回収
された無機塩化物に要求される純度等を考慮して
回収方法条件、装置等が決定される。例えば回収
する無機塩化物の必要純度がそれ程厳密でなけれ
ば抽廃水をそのまま、あるいは中和後濃縮する。
あるいは重金属イオンの一部を水酸化物として除
去後濃縮する等の方法を採る。さらに高純度の無
機塩化物が要求されるならば、抽廃水を重金属選
択吸着性のイオン交換樹脂あるいはキレート樹脂
で処理して完全に重金属を除去して濃縮回収する
といつた方法をとることができる。
なお、本発明の実施においては、N−アルキル
アミド水溶液中に、無機塩化物及び重金属イオン
以外の有機物、無機物が含まれていてもよく、又
抽剤中に含まれる安定剤等も何ら本発明の効果を
そこなわない。
以上詳記したように、本発明方法によれば耐熱
性、難燃性、高強力性、耐薬品性を有する有機ポ
リマーの重合、成形に好んで用いられるN−アル
キルアミドを水溶液から回収するにあたり、工程
的なトラブルを実質的に皆無にし、安定した工程
で、安価な高収率の回収が可能になり、さらに高
純度での回収が容易になりN−アルキルアミドの
品質を極めて安定なものとすることができる。
さらに本発明の効果は上記の如くN−アルキル
アミドの回収率、品質の向上に顕著であるだけで
なく、抽剤の分解を抑制する効果をも奏するもの
であつて、抽剤の原単位を低下せしめ、無機塩化
物の回収においても高純度のものの回収を容易に
する著効を有する。
以下に本発明の実施例及び比較例を掲記し、本
発明の実施態様及び効果をより具体的に示す。
なお実施例中の重金属イオンの定量は、吸光光
度法(JIS−K−0102等)によつて測定したもの
であり、ppm単位はmg/で表示したものであ
る。
また重金属イオン以外の物質の含量を表示する
%、重量%による表示である。
実施例中のポリマーの重合度を表わすパラメー
ターとして用いる対数粘度(ηinh)は、次式に
よつて定義される。
ηinh=ln ηr/0.5
(式中、ηrは98重量%硫酸中でのポリマー濃度
0.5g/100mlの相対粘度を示し、25℃で毛細管粘
度計で測定したポリマー溶液と98重量%硫酸との
落下秒数の比である。)
実施例 1
撹拌機を有するSUS304製の容器に、N・N−
ジメチルアセトアミド(以下DMAと略記する。)
を1.0Kg仕込み、塩化リチウム50gとメタフエニ
レンジアミン108gを溶解した。これらが溶解し
た後、イソフタル酸クロライド203gを粉末状で
一時に添加し、撹拌を行つた。撹拌に要する動力
負荷が液の粘度と共に上昇し、30分後に負荷が一
定になり重合は終了した。得られた粘稠な液を水
酸化リチウム48gを含む水と共に、小型ミキサー
にて混合して重合したポリ−メタフエニレンイソ
フタルアミドを凝固させ、ガラスフイルターにて
該ポリマーを分離して回収すべきDMAの水溶液
を得た。
この水溶液はPH=6.7であり、DMAを23%、塩
化リチウムを3%含有しており、重金属として鉄
イオンを15ppm、クロムイオンを2ppm、ニツケ
ルイオンを1ppm、マンガンイオンを1ppm含ん
でいた。
このDMA水溶液を100g採取して、0.1N塩酸水
溶液でPH=4.0に調整して分液漏斗に入れ、ジク
ロルメタン100gを添加して振とう後静置させ
た。液は完全に二相に分離され、界面等に異物の
発生はなく、容易に二相を分取できた。DMAの
抽出相濃度は10%、抽廃水相濃度は19%であつ
た。
比較例 1
実施例1で用いたDMA水溶液100gをPH調整す
ることなく、実施例1と同様にジクロルメタン
100gを添加して分液漏斗で分離を試みた。
液は二相に分離されDMAの抽出相、抽廃水相
への分配は実施例1と同様の値であつたが、界面
近辺に褐色の浮遊性のある固形物が析出してお
り、界面近辺の二相の分取は困難であつた。
実施例 2
撹拌機を有するSUS 316製の容器にN−メチル
ピロリドン(以下、NMPと略記する。)を500g
入れて、25gの塩化リチウムと、15.5gのテレフ
タル酸ジヒドラジド及び2.2gのパラフエニレン
ジアミンを溶解した。この系を冷却し、撹拌を続
けながら20.3gのテレフタル酸クロライドを粉末
状で一時に添加した。粘度の急速な上昇がみら
れ、1時間後に透明なポリアミドヒドラジドの溶
液が得られた。この溶液に、水酸化リチウム4.8
gを含む水でポリマーを凝固させ、ポリマーを漏
別してNMPの水溶液を得た。
この水溶液はPH=7.5であり、NMPを25%、塩
化リチウムを1.7%含有しており、重金属として
鉄イオンを10ppm、クロム、ニツケルの各イオ
ンをそれぞれ1ppm含んでいた。
このNMP水溶液を100g採取し、0.1N塩酸でPH
=3.5に調整して分液漏斗に入れ、クロロホルム
を100g添加して振とう後静置させた。液は完全
に二相に分離し容易に二相を分取できた。
なお、NMPの濃度は抽出相が14%、抽廃水相
が12%であつた。
比較例 2
実施例2で用いたNMP水溶液100gをPH調整す
ることなく実施例2と同様にクロロホホルム100
gを添加し、分液漏斗での分離を試みた。
液は二相に分離され、抽出相、抽廃水相の
NMP濃度は実施例2と同様の値であつたが、界
面近辺に黄褐色の浮遊性のある固形物が析出して
おり、界面近辺の二相の分取は容易ではなかつ
た。
実施例 3
ポリ−メタフエニレンイソフタルアミドを塩化
カルシウム5%を含有するDMAに溶解し、ポリ
マー濃度が20%の成形用の原液を作成し、SUS
316製の湿式紡糸設備を用いたポリ−メタフエニ
レンイソフタルアミドを紡糸する実験を行ない、
凝固浴組成は塩化カルシウム25%、DMA30%の
水溶液とし、この凝固浴からDMAを回収するた
めの検討を実施した。
この液はPH=7.8であり重金属として、鉄イオ
ンを45ppm、クロムイオン及びマンガンイオン
をそれぞれ2ppm含んでいた。
この液をPH=3.0に調整した後、連続抽出装置
により、抽出回収する実験を実施した。抽出装置
はガラス製25mmφ、高さ1.5mのパイプにSUS
316製のラシヒリングを有する充填塔及び定量ポ
ンプ、タンクよりなる装置であり、DMA水溶液
を塔底より180g/分、抽剤の1・1・2−トク
ロルエタンを塔頂より200g/分の流量で連続し
て流した。連続して8時間の運転が可能であり、
それ以降の運転にも支障をきたす事象はみられな
かつた。また抽廃水中のDMA濃度はガスクロマ
トグラフイー法によつては検出できない量
(50ppm以下)であり、完全な抽出操作が可能で
あつた。
比較例 3
実施例3で用いたDMA水溶液を調整すること
なく同一装置及び同一条件で抽出処理を行つた。
運転開始後30分頃から明らかな褐色固形物の充填
塔内部での発生がみられ、1時間後には充塔物へ
の付着による塔内部随所での偏流がみられた。そ
してこの時点での抽廃水中のDMA濃度はガスク
ロマトグラフイー法による定量が可能であり、
300ppmであつた。さらに1時間の運転で褐色固
形物の析出が激しくなり、抽廃水相や抽出液中に
浮遊物が見られるに至り、抽出操作が不可能にな
つた。
実施例 4
SUS製の重合装置を用いてポリ−パラフエニレ
ンテレフタルアミドの重合を実施し、その重合に
用いた溶剤を回収し、くり返し重合に使用するテ
ストを実施した。
入荷精製したNMPを撹拌機構を有するSUS
304製容器に10Kg仕込み、それに塩化カルシウム
を800g、パラフエニレンジアミンを540gを添加
して溶解した後、テレフタル酸クロライド1015g
を撹拌下に粉末状で添加した。この液は急速に粘
度を増し約3分でゲル状に変化し、それ以上の撹
拌が困難になつた。このゲル状物をすばやく回分
式ニーダーに移し、15分間破砕・混練し重合を完
了させた。得られた粉末状の重合体をヘンシエル
ミキサーに移し、285gの水酸化カルシウムを含
むスラリー水溶液を加えて混合してポリマーを凝
固させた。固液を分離し、ポリマーは水洗・乾燥
される一方、NMP水溶液は回収されるべく貯槽
にストツクさせた。
上記重合操作を5回繰り返しηinhは、以下の
如き数値となつた。
5.62、5.54、5.64、5.68、5.57
一方ストツクされたNMP水溶液は全体混合さ
れ、PH=7.2で35%のNMPを含み、塩化カルシウ
ムを4.7%含んでおり、鉄イオンを30ppmクロム
イオンを5ppm、ニツケルイオンを2ppm、マン
ガンイオンを1ppm含んでいた。
この水溶液の半量を用いて、以下の回収操作を
実施して、再び重合に供した。
まず水溶液を0.1N塩酸水溶液にてPH=4.0調整
し、連続抽出装置による抽出回収した。即ち抽出
装置は、ガラス製の25mmφで高さ1.5mのパイプ
に磁製のインターロツクサドルを入れた充填塔、
及び定量ポンプ、タンクよりなる装置であり、
NMP水溶液を塔底より200g/分、抽剤のジクロ
ルメタンを塔頂より300g/分の流量で流し、連
続処理を行つた。得られた抽出相よりNMPを回
収するために、蒸留塔にて分離蒸留を行ない、ジ
クロルメタンを除去後、NMPの本留分として10
Kgを得た。
この液を用いて再び同一装置、同一条件、同一
の原料(ただしNMPを除く。)でポリ−パラフエ
ニレンテレフタルアミドの重合を実施したところ
そのηinhは5.71であつた。
比較例 4
実施例4の当初の重合から得た回収液の半量を
用いて従来技術による抽出回収を実施して再び重
合に使用した例を示す。
重合回収液をPH調整することなく、実施例3と
同一の充填塔による処理は固形物の発生のために
出来なかつた。そこで重合回収液をPH=9に
0.1Nの水酸化ナトリウム水溶液で調整し、含有
される重金属を水酸化物としてポリプロピレン製
の布を用いて漏別した後再び塩酸にて中和しPH=
7の中性とした。漏過された液中の重金属含有量
は、鉄イオンが2ppmに低下しており、ニツケ
ル、クロロホルム、マンガンの各イオンは検出限
界以下であることが判つた。このようにほとんど
の重金属を除去した後、実施例4と同一の装置を
用い、同一条件によつて抽出を実施したところ抽
出時の固形物の析出はわずかに観察されたが、こ
の量の処理では工程に支障を与えなかつた。得ら
れた抽出液を実施例3と同様に蒸留塔にて分離蒸
留し、ジクロルメタンを除去後、NMPの本留分
として10Kgを採取した。
この液を用いてポリ−パラフエニレンテレフタ
ルアミドの重合を実施したが、そのηinhは3.83
と当初の重合に比して明らかな低下を示してい
た。
実施例5〜7(比較例5〜6)
撹拌機構を有するSUS 304製容器に、入荷精製
したDMAを10Kg仕込み、500gの塩化リチウム、
1080gのメタフエニレンジアミンを溶解し、イソ
フタル酸クロライドを2030g粉末状で添加し1時
間撹拌することによつて粘稠なポリマー溶液を得
た。この溶液を800gの水酸化ナトリウムを含む
水と共にヘンシエルミキサーに移し、ポリマーを
凝固、粉砕して回収すべきDMAの水溶液を得
た。一方得られたポリマーを洗浄して溶液粘度を
測定したところηinh=2.28であつた。
このようにして得られたDMAの水溶液はPH=
6.8で、鉄イオンを19ppm、クロムイオンを
3ppm、ニツケルイオンを1ppm含有していた。
このDMAの水溶液を5分割し、それぞれ以下の
所定のPHに調整した後、1・2−ジクロルエタン
にて抽出し、それぞれを蒸留精製し、回収DMA
を得て実施例1で示したポリメタフエニレンイソ
フタルアミドの重合を行つた。このようにして得
られた回収DMAを用いた重合結果を次表に示
す。
The present invention relates to a method for recovering N-alkylamide from an aqueous N-alkylamide solution containing inorganic chloride and heavy metal ions. The purpose is to provide a method for recovering N-alkylamide from an aqueous N-alkylamide solution containing inorganic chloride and heavy metal ions in a stable process, at low cost, in good yield, and with high purity. In recent years, there has been a strong demand in the industry for organic materials that have heat resistance, flame retardance, high strength, chemical resistance, and dimensional stability.
2. Description of the Related Art So-called organic heat-resistant polymers such as polyamide hydrazide, polyamideimide, and polyimide are being actively produced. These materials have already been formed into fibers, films, papers, tapes, etc. and used as various industrial products. However, these polymers are extremely poorly soluble and do not dissolve in ordinary inexpensive organic solvents.
In order to polymerize and mold polymers, expensive solvents called N-alkylamides such as N・N-dimethylacetamide and N-methylpyrrolidone, and inorganic solvents such as lithium chloride and calcium chloride are used as solvent aids. A mixture of chlorides is used. Polymers polymerized using N-alkylamides containing inorganic chlorides and molded articles are usually washed with water and isolated. On the other hand, N
- The alkylamides together with the inorganic chlorides are separated from the polymers and moldings in the form of aqueous solutions. and,
Since N-alkylamides are expensive, they must be recovered and reused, and the challenge in this industry is how to recover high-purity N-alkylamides from this aqueous solution at a high yield and at low cost. It is said to hold the key to success. There is a well-known method for extracting and recovering N-alkylamides from an aqueous solution of N-alkylamides and inorganic chloride (calcium chloride) used for polymer molding with dichloromethane or other extracting agent (Tokuko-Sho).
48-23415, Special Publication No. 49-48432). However, when used in polymerization, such as the reaction of aromatic dicarboxylic acid chloride and aromatic diamine to obtain aromatic polyamide, N It has been found that when extracting and recovering -alkylamides using this method, there are problems both in terms of the quality of the N-alkylamides obtained by recovery and in the process of extraction and recovery. That is, the problem with the quality of the recovered N-alkylamide is the phenomenon that when polymerization is carried out using this solvent again, the degree of polymerization of the resulting polymer is no longer sufficient. Although the cause of this is not clear, it is presumed that the recovered N-alkylamide contains impurities that inhibit polymerization, and we are investigating the identification of these impurities by means such as gas chromatography and mass spectroscopy. However, it has not yet been elucidated. Further, process problems in extraction and recovery are caused by solid matter (so-called "slag") that occurs when the aqueous solution and extractant come into contact during the extraction operation. According to the investigation by the present inventors, this solid substance is due to heavy metal ions mixed in the N-alkylamide aqueous solution, and is a combination of N-alkylamide or its decomposition products with heavy metals and inorganic substances in some way. It was estimated that This solid matter is generated during the extraction operation, adheres to the inside of the extraction device, reduces the contact area for liquid-liquid extraction, gradually reduces the extraction rate, and finally makes the extraction operation impossible.
In addition, this solid substance has a floating property, so it mixes into the extraction waste water and the extraction phase, and even in the recovery process after the extraction process, it can cause various problems such as adhering to heat exchangers etc. and impairing heat conduction. cause trouble. The contamination of heavy metal ions that cause this trouble is due to those originally contained in certain inorganic chlorides and due to corrosion of equipment materials by hydrochloric acid generated during polymerization. As is well known, hydrochloric acid corrodes iron and SUS materials that are generally used as equipment materials, and in order to completely eliminate corrosion, it is necessary to use very expensive materials or to take measures such as Teflon or glass lining or coating. There must be. However, it is economically difficult to make all devices that come into contact with these compounds using such materials, and it is also physically difficult due to the mechanical strength required for the devices and the workability during device manufacturing. In most cases it is possible,
It is an unavoidable fact that heavy metal ions are mixed into the aqueous solution of N-alkylamide used as a polymerization solvent to be recovered. The present inventors have discovered that in the extraction and recovery of N-alkylamides from such N-alkylamide aqueous solutions containing inorganic chlorides and heavy metal ions, the extraction operation can be performed smoothly and can be recovered with high purity and good yield. As a result of studying to develop an improved method, we succeeded in preventing the generation of solids during extraction by adjusting the aqueous solution to a specific pH range. Furthermore, by performing an extraction operation on the aqueous solution in a specific pH range, it is possible to reduce the polymerization-inhibiting impurities in the recovered N-alkylamide to an amount that does not actually participate in polymerization, and the recovered N −
It was discovered that quality problems with alkylamides could be solved all at once. The present invention has been completed based on the above findings and has achieved the intended purpose. That is, the present invention uses 1 to 50% by weight of inorganic chloride and
Extraction of N-alkylamide by adjusting the pH of the aqueous solution to 2.5 to 5.5 and extracting with an extractant when recovering N-alkylamide from an N-alkylamide aqueous solution containing 5 ppm or more of heavy metal ions. This is a collection method. Conventionally, when extracting an N-alkylamide aqueous solution, keeping the aqueous solution acidic meant that N-
This was considered undesirable due to the stability of alkylamides against hydrolysis. However, in the method of the present invention, by adjusting this aqueous solution to a specific pH range and performing extraction, it has become possible to recover N-alkylamide at low cost, in good yield, and with high purity in a stable process. is surprising. Why is it that in the PH range found by the present invention, the solids generated in the conventional technology are not generated, and impurities that inhibit polymerization are removed from the N-
Although it is not clear whether they are no longer included in alkylamides, it is presumed that the extraction rate of these substances changes depending on the pH of the aqueous solution. The present invention can be applied not only to an aqueous N-alkylamide solution used in polymerization, but also to an aqueous N-alkylamide solution used in molding. In other words, N-alkylamides containing inorganic chlorides used as coagulation liquids for long-term molding corrode equipment and materials due to the corrosivity of inorganic chlorides, contain non-negligible amounts of heavy metal ions, and This is because the polymer also contains impurities that inhibit the reaction during polymerization due to decomposition of alkylamides, etc. In such cases, the effects of the present invention are exhibited. N-alkylamide as used in the present invention means N.N.
It refers to solvents such as -dimethylacetamide, N-methylpyrrolidone, tetramethylurea, N-acetylpyrrolidine, and N-acetylmorpholine, which may be used singly or in a mixture of two or more. In the present invention, the inorganic chloride contained in the N-alkylamide aqueous solution refers to chloride which is known to be advantageous when coexisting when polymerizing or molding a polymer using N-alkylamide. Refers to inorganic chlorides added during polymerization or molding of lithium, magnesium chloride, calcium chloride, zinc chloride, etc., and also refers to the above inorganic chlorides produced by neutralizing hydrochloric acid produced as a by-product during polymerization using dicarboxylic acid chloride. Also included are chlorides and by-product inorganic chlorides such as sodium chloride and ammonium chloride. These inorganic chlorides may be used alone or in a mixture of two or more without impairing the effects of the present invention, and the concentration in the aqueous solution may be 1 to 1 by weight.
Applies to the invention in 50% of cases. In the present invention, the pH of the N-alkylamide aqueous solution is
Any value between 2.5 and 5.5 may be taken. However, studies conducted by the present inventors have revealed that the upper limit of the pH range suitable for recovering N-alkylamides in a stable process is correlated with the concentration of heavy metal ions contained in the aqueous solution. In other words, the heavy metal ions used in the present invention are metal ions of the elements that constitute various iron materials and SUS materials that are used as general equipment materials, and that constitute the fourth period of the periodic table. , iron, nickel, chrome,
Each type of manganese ion is included, and a mixture of two or more types may be used, but if the total of these heavy metal ions exceeds 5 ppm, solid matter will precipitate during extraction, and to prevent this, the pH of the aqueous solution must be below 6.0. It was necessary to do so. By the way, heavy metal ions
The upper limit of PH value suitable for 50 ppm is 5.2, and depending on the concentration of heavy metal ions, the pH value below these upper limits may be
Process troubles can be avoided by taking the PH value. On the other hand, preventing impurities that inhibit polymerization from being mixed into the recovered solvent can be achieved by adjusting the pH of the aqueous solution to 2.5 to 5.5. More favorable PH
The range is 3.0-5.0. Any method may be used for extraction when the pH of the N-alkylamide aqueous solution is 2.5 to 5.5. An easily adopted method is to adjust the pH to the range of the present invention before carrying out the extraction operation of an N-alkylamide aqueous solution containing inorganic chloride and heavy metal ions. That is, this is a method of adjusting the pH by adding a small amount of an acid such as hydrochloric acid to a neutralized aqueous solution. In addition, in cases where hydrochloric acid is produced as a by-product during polymerization using N-alkylamides, in addition to the above-mentioned method of adding acids to an already neutralized aqueous solution, it is possible to Any method may be used to neutralize only a portion of the by-produced hydrochloric acid, or to maintain the pH within the range of the present invention without performing any neutralization operation. In some cases, a method may be adopted in which acids are added to the extraction agent to substantially adjust the pH of the aqueous phase during extraction to 2.5 to 5.5. It is also recommended to prevent decomposition of the agent. The extraction agent used in the extraction of the present invention may be the extraction agent used for the extraction of N-alkylamides from ordinary aqueous solutions, such as halogenated hydrocarbons such as dichloromethane and chlorobenzene, hydrocarbons such as benzene, etc.
Higher alcohols such as amyl alcohol, ester compounds such as diethyl oxalate, and nitrile compounds such as adiponitrile and benzonitrile are known. According to the studies of the present inventors, halogenated hydrocarbons are preferable as extractants of the present invention, and more preferably dichloromethane, 1,2-dichloroethane, chloroform, 1,1,2-trichloroethane, These may be used alone or in combination of two or more. It has been found that these halogenated hydrocarbons not only have excellent extraction efficiency, but also that the decomposition of the extractant itself is suppressed by contact with the acidic aqueous solution, which is a feature of the present invention, resulting in good results. Conditions for extracting N-alkylamide using this extractant, ie, extraction temperature, amount of extractant, etc., can be arbitrarily selected depending on the type of N-alkylamide, the concentration in the aqueous solution, and the type of extractant. Also, the equipment used for this extraction is not particularly limited,
Regardless of continuous type or batch type, use a tower with built-in rotary vanes, a packed type tower, a tray type tower, an extraction device using centrifugal force, an extraction device using baffles, or a mixing tank with a normal stirring function. Extraction equipment etc. can be used effectively. Also, from the extracted phase extracted according to the present invention, N
- The method for recovering the alkylamides is not limited, and various methods for separating general N-alkylamides and extractants may be used. An easy method is conventional separation distillation, which can be used either continuously or batchwise. N- to be collected
The purity of the alkylamide can be arbitrarily selected depending on the conditions for reuse. Moreover, in the case of the present invention, since there is no contamination of solid matter, the amount of N-alkylamide to be removed as a distillation residue is reduced, and the recovery rate of N-alkylamide can be dramatically increased. Furthermore, since there are no solids present during distillation, there is no reduction in heat conduction due to solids adhering to the heat exchanger, and no flooding phenomenon occurs, resulting in stable quality recovered N-alkylamide. can be obtained. Any method may be used to treat the extracted waste water generated by carrying out the present invention. That is, the extraction water obtained by the present invention exhibits acidity,
It is optional to neutralize and slowly release the inorganic chloride, or to recover the contained inorganic chloride, and the cost of the inorganic chloride and
This is determined to be the cost required for recovery. Generally, it is advantageous to recover the higher the concentration of inorganic chloride;
The method for this may also be freely chosen. That is, the recovery method conditions, equipment, etc. are determined in consideration of the purity required for the recovered inorganic chloride. For example, if the required purity of the inorganic chloride to be recovered is not so strict, the extraction waste water may be concentrated as is or after neutralization.
Alternatively, a method such as removing a portion of the heavy metal ions as hydroxide and then concentrating it may be used. If even higher purity inorganic chlorides are required, methods such as treating extracted wastewater with an ion exchange resin or chelate resin that selectively adsorbs heavy metals to completely remove heavy metals and concentrate recovery can be used. . In the practice of the present invention, organic substances and inorganic substances other than inorganic chlorides and heavy metal ions may be contained in the N-alkylamide aqueous solution, and stabilizers and the like contained in the extraction agent are not included in the present invention. does not impair the effect of As detailed above, according to the method of the present invention, N-alkylamides, which are preferably used in the polymerization and molding of organic polymers having heat resistance, flame retardancy, high strength, and chemical resistance, can be recovered from aqueous solutions. , with virtually no process troubles and a stable process, it is possible to recover inexpensively and in high yields, and it is also easy to recover with high purity, making the quality of N-alkylamides extremely stable. It can be done. Furthermore, the effects of the present invention are not only remarkable in improving the recovery rate and quality of N-alkylamides as described above, but also suppressing the decomposition of extractants, and reducing the basic unit of extractants. It also has a remarkable effect in making it easier to recover high-purity inorganic chlorides. Examples and comparative examples of the present invention are listed below to more specifically illustrate the embodiments and effects of the present invention. In addition, the quantitative determination of heavy metal ions in the examples was determined by spectrophotometry (JIS-K-0102, etc.), and the ppm unit is expressed in mg/. In addition, the content of substances other than heavy metal ions is expressed in terms of % and weight %. The logarithmic viscosity (ηinh) used as a parameter representing the degree of polymerization of the polymer in the examples is defined by the following formula. ηinh=ln ηr/0.5 (where ηr is the polymer concentration in 98% by weight sulfuric acid
It exhibits a relative viscosity of 0.5 g/100 ml, which is the ratio of the number of seconds of fall between the polymer solution and 98% by weight sulfuric acid, measured with a capillary viscometer at 25°C. ) Example 1 N/N- was placed in a SUS304 container equipped with a stirrer.
Dimethylacetamide (hereinafter abbreviated as DMA)
1.0 kg of lithium chloride was charged and 50 g of lithium chloride and 108 g of metaphenylenediamine were dissolved. After these were dissolved, 203 g of isophthalic acid chloride was added all at once in powder form and stirred. The power load required for stirring increased with the viscosity of the liquid, and after 30 minutes, the load became constant and polymerization was completed. The resulting viscous liquid should be mixed with water containing 48 g of lithium hydroxide in a small mixer to solidify the polymerized poly-metaphenylene isophthalamide, and the polymer should be separated and recovered using a glass filter. An aqueous solution of DMA was obtained. This aqueous solution had a pH of 6.7, contained 23% DMA, 3% lithium chloride, and contained heavy metals such as 15 ppm iron ions, 2 ppm chromium ions, 1 ppm nickel ions, and 1 ppm manganese ions. 100 g of this DMA aqueous solution was collected, adjusted to PH = 4.0 with 0.1N aqueous hydrochloric acid solution, placed in a separatory funnel, added with 100 g of dichloromethane, shaken, and allowed to stand still. The liquid was completely separated into two phases, no foreign matter was generated at the interface, etc., and the two phases could be easily separated. The concentration of DMA in the extracted phase was 10%, and the concentration in the extracted water phase was 19%. Comparative Example 1 100g of the DMA aqueous solution used in Example 1 was added to dichloromethane in the same manner as in Example 1 without adjusting the pH.
100g was added and separation was attempted using a separatory funnel. The liquid was separated into two phases, and the distribution of DMA into the extraction phase and extracted water phase was the same as in Example 1, but a brown floating solid was precipitated near the interface. It was difficult to separate the two phases. Example 2 500g of N-methylpyrrolidone (hereinafter abbreviated as NMP) was placed in a SUS 316 container equipped with a stirrer.
and dissolved 25 g of lithium chloride, 15.5 g of terephthalic acid dihydrazide, and 2.2 g of paraphenylene diamine. The system was cooled and 20.3 g of terephthalyl chloride was added in powder form all at once while stirring was continued. A rapid increase in viscosity was observed and a clear polyamide hydrazide solution was obtained after 1 hour. Add 4.8 lithium hydroxide to this solution.
The polymer was coagulated with water containing g, and the polymer was filtered off to obtain an aqueous solution of NMP. This aqueous solution had a pH of 7.5, contained 25% NMP and 1.7% lithium chloride, and contained 10 ppm of iron ions and 1 ppm each of chromium and nickel ions as heavy metals. Collect 100g of this NMP aqueous solution and pH it with 0.1N hydrochloric acid.
= 3.5 and placed in a separatory funnel, 100 g of chloroform was added, shaken, and allowed to stand still. The liquid was completely separated into two phases, and the two phases could be easily separated. Note that the concentration of NMP was 14% in the extraction phase and 12% in the extracted water phase. Comparative Example 2 100 g of the NMP aqueous solution used in Example 2 was mixed with 100 g of chlorophoform in the same manner as in Example 2 without adjusting the pH.
g was added and separation using a separatory funnel was attempted. The liquid is separated into two phases: the extraction phase and the extracted water phase.
Although the NMP concentration was the same as in Example 2, a yellow-brown floating solid was precipitated near the interface, making it difficult to separate the two phases near the interface. Example 3 Poly-metaphenylene isophthalamide was dissolved in DMA containing 5% calcium chloride to create a stock solution for molding with a polymer concentration of 20%, and SUS
We conducted an experiment to spin poly-metaphenylene isophthalamide using wet spinning equipment manufactured by 316.
The coagulation bath composition was an aqueous solution of 25% calcium chloride and 30% DMA, and a study was conducted to recover DMA from this coagulation bath. This liquid had a pH of 7.8 and contained 45 ppm of iron ions, 2 ppm each of chromium ions and manganese ions as heavy metals. After adjusting the pH of this liquid to 3.0, an experiment was conducted in which it was extracted and recovered using a continuous extraction device. The extraction device is made of glass with a diameter of 25 mm and a pipe with a height of 1.5 m and SUS.
The equipment consists of a packed column with a Raschig ring made of 316, a metering pump, and a tank, and the DMA aqueous solution is continuously fed at a flow rate of 180 g/min from the bottom of the column, and the extractant 1,1,2-tochloroethane is continuously fed at a flow rate of 200 g/min from the top of the column. I washed it away. It can be operated continuously for 8 hours,
There were no occurrences that would interfere with subsequent driving. Furthermore, the DMA concentration in the extracted waste water was undetectable by gas chromatography (less than 50 ppm), and complete extraction operations were possible. Comparative Example 3 The DMA aqueous solution used in Example 3 was extracted using the same apparatus and under the same conditions without adjustment.
Approximately 30 minutes after the start of operation, brown solids were clearly generated inside the packed column, and after one hour, uneven flow was observed throughout the column due to adhesion to the packed column. The DMA concentration in the extracted wastewater at this point can be determined by gas chromatography.
It was 300ppm. After a further 1 hour of operation, the precipitation of brown solids became intense, and floating substances were observed in the extracted water phase and extract liquid, making the extraction operation impossible. Example 4 Poly-paraphenylene terephthalamide was polymerized using a polymerization apparatus made of SUS, and the solvent used in the polymerization was recovered and tested for use in repeated polymerizations. SUS with a stirring mechanism for incoming purified NMP
Pour 10kg into a 304 container, add 800g of calcium chloride and 540g of paraphenylenediamine and dissolve, then 1015g of terephthalic acid chloride.
was added in powder form while stirring. This liquid rapidly increased in viscosity and turned into a gel in about 3 minutes, making further stirring difficult. This gel-like material was quickly transferred to a batch kneader, and crushed and kneaded for 15 minutes to complete polymerization. The obtained powdered polymer was transferred to a Henschel mixer, and an aqueous slurry solution containing 285 g of calcium hydroxide was added and mixed to solidify the polymer. The solid and liquid were separated, and the polymer was washed with water and dried, while the NMP aqueous solution was stored in a storage tank to be recovered. The above polymerization operation was repeated 5 times to obtain ηinh as shown below. 5.62, 5.54, 5.64, 5.68, 5.57 On the other hand, the stocked NMP aqueous solution was completely mixed and contained 35% NMP at pH=7.2, 4.7% calcium chloride, 30 ppm iron ions, 5 ppm chromium ions, and nickel. It contained 2 ppm of ions and 1 ppm of manganese ions. Using half of this aqueous solution, the following recovery operation was performed and the solution was subjected to polymerization again. First, the aqueous solution was adjusted to PH=4.0 with a 0.1N aqueous hydrochloric acid solution, and extracted and collected using a continuous extraction device. In other words, the extraction device is a packed tower made of a glass pipe with a diameter of 25 mm and a height of 1.5 m and a porcelain interlock saddle.
It is a device consisting of a metering pump and a tank,
Continuous treatment was carried out by flowing the NMP aqueous solution from the bottom of the column at a flow rate of 200 g/min and the extractant dichloromethane from the top of the column at a flow rate of 300 g/min. In order to recover NMP from the obtained extraction phase, separate distillation is performed in a distillation column, and after removing dichloromethane, 10
Got Kg. Using this solution, poly-paraphenylene terephthalamide was polymerized again using the same equipment, the same conditions, and the same raw materials (excluding NMP), and the ηinh was 5.71. Comparative Example 4 An example is shown in which half of the recovered liquid obtained from the initial polymerization in Example 4 was extracted and recovered by conventional techniques and used again for polymerization. The polymerization recovery liquid could not be treated in the same packed tower as in Example 3 without adjusting the pH due to the generation of solid matter. Therefore, the pH of the polymerization recovery liquid was adjusted to 9.
Adjust with 0.1N sodium hydroxide aqueous solution, remove the contained heavy metals as hydroxide using a polypropylene cloth, and then neutralize with hydrochloric acid again to obtain PH=
It was set as neutral of 7. It was found that the heavy metal content in the leaked liquid had decreased to 2 ppm for iron ions, and that nickel, chloroform, and manganese ions were below the detection limit. After removing most of the heavy metals in this way, extraction was carried out using the same equipment and under the same conditions as in Example 4, and a slight amount of solid matter was observed to precipitate during extraction. There was no hindrance to the process. The obtained extract was subjected to separate distillation in a distillation column in the same manner as in Example 3, and after removing dichloromethane, 10 kg was collected as the main fraction of NMP. This solution was used to polymerize poly-paraphenylene terephthalamide, and its ηinh was 3.83.
This showed a clear decrease compared to the initial polymerization. Examples 5 to 7 (Comparative Examples 5 to 6) Into a SUS 304 container with a stirring mechanism, 10 kg of incoming purified DMA was charged, and 500 g of lithium chloride,
A viscous polymer solution was obtained by dissolving 1080 g of metaphenylene diamine, adding 2030 g of isophthaloyl chloride in powder form, and stirring for 1 hour. This solution was transferred to a Henschel mixer together with 800 g of water containing sodium hydroxide, and the polymer was coagulated and ground to obtain an aqueous solution of DMA to be recovered. On the other hand, when the obtained polymer was washed and the solution viscosity was measured, it was found to be ηinh=2.28. The aqueous solution of DMA thus obtained has a pH of
6.8, 19ppm iron ions, chromium ions
It contained 3ppm and 1ppm of nickel ions.
This DMA aqueous solution was divided into 5 parts, each adjusted to the specified pH below, extracted with 1,2-dichloroethane, purified by distillation, and recovered DMA.
The obtained product was used to polymerize polymetaphenylene isophthalamide as shown in Example 1. The results of polymerization using the recovered DMA thus obtained are shown in the following table.
【表】【table】
Claims (1)
重金属イオンを含有するN−アルキルアミド水溶
液からN−アルキルアミドを回収するにあたり、
該水溶液のPHを2.5〜5.5に調整した後、抽剤で抽
出することを特徴とするN−アルキルアミドの抽
出回収方法。 2 N−アルキルアミド水溶液に含まれる重金属
イオンが周期律表において第4周期の族、
族、及び族を構成する元素のうちの1種あるい
は2種以上の金属元素イオンである特許請求の範
囲第1項に記載のN−アルキルアミドの回収方
法。 3 抽剤としてジクロルメタン、1・2−ジクロ
ルエタン、クロロホルム、1・1・2−トリクロ
ルエタンよりなる群から選ばれる少なくとも1種
のハロゲン化炭化水素を用いる特許請求の範囲第
1項に記載のN−アルキルアミドの回収方法。[Claims] 1. In recovering N-alkylamide from an aqueous N-alkylamide solution containing 1 to 50% by weight of inorganic chloride and 5 ppm or more of heavy metal ions,
A method for extracting and recovering N-alkylamides, which comprises adjusting the pH of the aqueous solution to 2.5 to 5.5, and then extracting with an extractant. 2. The heavy metal ions contained in the N-alkylamide aqueous solution belong to the group 4 of the periodic table,
2. The method for recovering N-alkylamide according to claim 1, wherein the N-alkyl amide is a group and one or more metal element ions of the elements constituting the group. 3. N- according to claim 1, in which at least one halogenated hydrocarbon selected from the group consisting of dichloromethane, 1,2-dichloroethane, chloroform, and 1,1,2-trichloroethane is used as an extractant. Method for recovering alkylamide.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP8091678A JPS559009A (en) | 1978-07-05 | 1978-07-05 | Recovery of n-alkylamide |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP8091678A JPS559009A (en) | 1978-07-05 | 1978-07-05 | Recovery of n-alkylamide |
Publications (2)
Publication Number | Publication Date |
---|---|
JPS559009A JPS559009A (en) | 1980-01-22 |
JPS6210221B2 true JPS6210221B2 (en) | 1987-03-05 |
Family
ID=13731716
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP8091678A Granted JPS559009A (en) | 1978-07-05 | 1978-07-05 | Recovery of n-alkylamide |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPS559009A (en) |
Families Citing this family (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE3328350A1 (en) * | 1983-08-05 | 1985-02-14 | Röhm GmbH, 6100 Darmstadt | METHOD FOR PURIFYING METHACRYLAMIDOPROPYLTRIMETHYLAMMONIUM CHLORIDE AND RELATED COMPOUNDS |
JPS60252614A (en) * | 1984-05-29 | 1985-12-13 | Toa Nenryo Kogyo Kk | Block copolymer |
CN102399179B (en) * | 2010-09-17 | 2014-06-18 | 上海化学试剂研究所 | Production process for ultra-pure N-methylpyrrolidone |
CN102503880B (en) * | 2011-10-18 | 2013-10-02 | 华诺森(武汉)生物医药技术有限公司 | Method for purifying N-vinyl compound |
Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS4923415A (en) * | 1972-05-19 | 1974-03-01 | ||
JPS4948432A (en) * | 1972-09-09 | 1974-05-10 |
-
1978
- 1978-07-05 JP JP8091678A patent/JPS559009A/en active Granted
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS4923415A (en) * | 1972-05-19 | 1974-03-01 | ||
JPS4948432A (en) * | 1972-09-09 | 1974-05-10 |
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