JPS5943945B2 - ε↓−Method for purifying caprolactam - Google Patents
ε↓−Method for purifying caprolactamInfo
- Publication number
- JPS5943945B2 JPS5943945B2 JP1800378A JP1800378A JPS5943945B2 JP S5943945 B2 JPS5943945 B2 JP S5943945B2 JP 1800378 A JP1800378 A JP 1800378A JP 1800378 A JP1800378 A JP 1800378A JP S5943945 B2 JPS5943945 B2 JP S5943945B2
- Authority
- JP
- Japan
- Prior art keywords
- lactam
- crude
- aqueous solution
- caprolactam
- purifying
- 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
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- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
- Separation, Recovery Or Treatment Of Waste Materials Containing Plastics (AREA)
Description
【発明の詳細な説明】
本発明はポリカプラミドをリン酸あるいはアルカリ触媒
で解重合することにより回収された粗ラクタムの精製方
法に関する。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for purifying crude lactam recovered by depolymerizing polycapramide with a phosphoric acid or alkali catalyst.
環状ケトキシムのベツクマン転位により得られる粗ラク
タム、例えばε−カプロラクタムの精製については従来
より多くの研究がなされており種種の精製方法が提案さ
れている。Much research has been done on the purification of crude lactams, such as ε-caprolactam, obtained by Beckman rearrangement of cyclic ketoxime, and various purification methods have been proposed.
例えば粗ラクタムを多段式蒸留により精製する方法、ア
ルカリもしくはアルカリ金属の過酸化物の存在下に蒸留
する方法、有機溶剤を用いて抽出を行う方法、活性炭、
イオン交換樹脂などで処理する方法、再結晶による方法
、単に過マンガン酸カリウム、重クロム酸カリウムなど
により酸化精製する方法などが知られている。For example, methods for purifying crude lactams by multistage distillation, methods for distilling in the presence of alkali or alkali metal peroxides, methods for extraction using organic solvents, activated carbon,
Methods such as treatment with an ion exchange resin, recrystallization, and simple oxidation purification using potassium permanganate, potassium dichromate, etc. are known.
一方最近においては省資源的な立場、経済的な見地より
、ポリラクタムを熱解重合してラクタムを回収する方法
が重視されている。On the other hand, recently, from a resource-saving and economic standpoint, emphasis has been placed on a method of recovering lactam by thermally depolymerizing polylactam.
上記回収方法において、熱解重合された粗ラクタムを濃
厚な水溶液として回収しているが、この粗ラクタムは前
記の環状ケトキシムのベツクマン転位により得られるラ
クタムとは異なり、極めて精製が困難であり、また得ら
れるラクタムの品質も市販のものに比較してかなり低い
ものとなる。In the above recovery method, thermally depolymerized crude lactam is recovered as a concentrated aqueous solution, but unlike the lactam obtained by the Beckman rearrangement of a cyclic ketoxime, this crude lactam is extremely difficult to purify. The quality of the lactam obtained is also considerably lower than that commercially available.
これはポリカプラミドの熱解重合が280℃を土建る厳
しい反応条件にさらされるために必然的に得られた不純
物の種類、量が多くなること、またポリカプラミドに含
まれる種々の添加剤あるいはその染色に使用された染料
などが、不純物の原因となりやすいことなどのためと考
えられている。従来から行なわれている精製方法の1つ
として、回収された粗ラクタムを水溶液にして、中性に
て過マンガン酸カリウムで酸化し、副生する二酸化マン
ガンを分離した後の濾液をアルカリ性fで蒸留する方法
が有効とされているが、この方法でも得られるラクタム
の品質は、あまり高くなく、揮発性塩基含有量(以下V
Bという)および遊離塩基含有量(以下FBという)な
どは、市販のラクタムより高い値を示す。したがつて上
記方法で得られたラクタムだけを用いて、繊維製造に適
する高品質のポリカプラミドを製造することは非常に困
難である。This is due to the fact that the thermal depolymerization of polycapramide is exposed to harsh reaction conditions at 280°C, which inevitably results in a large number of impurities, as well as the various additives contained in polycapramide or the dyeing process. This is thought to be because the dyes used tend to cause impurities. One of the conventional purification methods is to make the recovered crude lactam into an aqueous solution, oxidize it with potassium permanganate under neutral conditions, and separate the by-product manganese dioxide, and then immerse the filtrate in alkaline f. Distillation is said to be effective, but the quality of the lactam obtained by this method is not very high, and the volatile base content (hereinafter referred to as V
B) and free base content (hereinafter referred to as FB) are higher than those of commercially available lactams. Therefore, it is very difficult to produce high quality polycapramide suitable for fiber production using only the lactam obtained by the above method.
そこで本発明者らは、上記の事情に鑑み、回収された粗
ラクタムを簡単な操作で精製し、高品質のラクタムを得
るため鋭意検討を重ねた結果、以下に示す方法で所期の
目的を達成し得ることを見出した。In view of the above circumstances, the inventors of the present invention have conducted intensive studies to purify the recovered crude lactam using simple operations and obtain high-quality lactam. I found out what can be achieved.
すなわち本発明はポリカプラミドをリン酸系触媒または
アルカリ系触媒の存在下に熱解重合して得られる粗ε−
カプロラタタムを精製するに際し、該粗ε一カプロラク
タムの水溶液をPH2〜6の酸性下で蒸留する工程およ
びPHlO〜14のアルカリ性下で蒸留する工程を経る
ことを特徴とするε一カプロラクタムの精製方法および
前記粗ε一カプロラクタムの水溶液を酸性下で蒸留し、
次いで酸化剤で処理した後、アルカリ性下で蒸留するこ
とを特徴とするε一カプロラクタムの精製方法である。
本発明において、粗ε一カプロラクタムの水溶液をPH
2〜6の酸性丁で蒸留するために用いられる酸性物質と
しては、硫酸、塩酸、硝酸、リン酸などの無機酸、蟻酸
、酢酸、モノクロール酢酸などの有機酸が適用でき、そ
れらは一種類でも、二種類以上併用してもよい。That is, the present invention provides crude ε-
A method for purifying ε-caprolactam, which comprises distilling an aqueous solution of the crude ε-caprolactam under acidic conditions of pH 2 to 6 and distilling it under alkalinity of pH 10 to 14 when purifying caprolatatum; An aqueous solution of crude ε-caprolactam is distilled under acidic conditions,
This is a method for purifying ε-caprolactam, which is characterized in that it is then treated with an oxidizing agent and then distilled under alkaline conditions.
In the present invention, an aqueous solution of crude ε-caprolactam is adjusted to pH
As the acidic substance used for distillation with 2 to 6 acidic acids, inorganic acids such as sulfuric acid, hydrochloric acid, nitric acid, and phosphoric acid, and organic acids such as formic acid, acetic acid, and monochloroacetic acid can be used. However, two or more types may be used in combination.
上記蒸留時のPHを2以下にすると、粗ラクタムの精製
効果は高く、高純度のラクタムが得られるが、蒸留時に
ラクタムが加水分解されやすいため、ε−アミノ−n−
カプロン酸の副生が多く、そのため精製後のラクタムの
収率が低下する結果となり好ましくない。またPHを6
以上にすると、粗ラクタムの精製効果が低くなるので好
ましくない。上記酸性下での蒸留工程を経たラクタムは
、凝縮させた水あるいは新たに水を添加して水溶液とし
、次いでアルカリ性下で蒸留を行うか、あるいは酸化剤
で処理した後アルカリ性下で蒸留を行う。If the pH during the above distillation is 2 or less, the purification effect of the crude lactam is high and a highly pure lactam can be obtained, but the lactam is easily hydrolyzed during the distillation, so ε-amino-n-
A large amount of caproic acid is produced as a by-product, which results in a decrease in the yield of lactam after purification, which is not preferable. Also, increase the pH to 6
If it is more than that, the effect of purifying the crude lactam will be lowered, which is not preferable. The lactam that has undergone the above-mentioned distillation process under acidic conditions is made into an aqueous solution by adding condensed water or new water, and then distilled under alkaline conditions, or treated with an oxidizing agent and then distilled under alkaline conditions.
前記酸化処理を行う場合、用いられる酸化剤として、過
マンガン酸カリウム、過マンガン酸ナトリウムなどの過
マンガン酸のアルカリ塩、次亜塩素酸ナトリウム、次亜
塩素酸カリウム、亜塩素酸ナトリウム、亜塩素酸カリウ
ムなどのハロゲン酸類のアルカリ塩、および過酸化水素
、過炭酸ナトリウム、過硼酸ナトリウム、オゾンなどが
用いられフる。When carrying out the above oxidation treatment, the oxidizing agents used include alkali salts of permanganic acid such as potassium permanganate and sodium permanganate, sodium hypochlorite, potassium hypochlorite, sodium chlorite, and chlorine. Alkali salts of halogen acids such as potassium acid, hydrogen peroxide, sodium percarbonate, sodium perborate, ozone, and the like are used.
本発明においては酸化した後の副生物の少ない過酸化水
素またはオゾンを用いるのが特に好ましい。たとえば過
酸化水素を使用する場合、前記酸性下蒸留工程を経たラ
クタム水溶液に、ラクタムに対して0,001〜0.5
重量%、好ましくは0.002〜0.01重量%の酸化
剤を添加した後攪拌する通常の方法に従うのが簡便であ
る。なお、上記の酸化剤の添加量または吸収量は他の酸
化条件や精製されるべきラクタム水溶液中の被酸化性不
純物の量により異なる。過酸化水素処理に必要な時間は
0.2〜2時間で充分である。In the present invention, it is particularly preferable to use hydrogen peroxide or ozone, which produces fewer by-products after oxidation. For example, when hydrogen peroxide is used, the lactam aqueous solution that has passed through the acidic distillation step has a concentration of 0.001 to 0.5% relative to the lactam.
It is convenient to follow the usual method of adding oxidizing agent in an amount of % by weight, preferably 0.002 to 0.01% by weight, followed by stirring. Note that the amount of the above-mentioned oxidizing agent added or absorbed varies depending on other oxidation conditions and the amount of oxidizable impurities in the lactam aqueous solution to be purified. A sufficient time for hydrogen peroxide treatment is 0.2 to 2 hours.
また処理を行う際にラクタム水溶液の温度が高すぎると
、不純物を酸化する以外に副反応も起こりやすくなり、
逆に温度が低すぎると、不純物が酸化されず、過剰の酸
化剤が残存する結果となり好ましくないので、できる限
り20〜60℃の範囲で行うよう注意すべきである。な
お上記過酸化水素処理はPHが10〜14、好ましくは
11〜13で行うと、より強い酸化力を発揮するので、
水酸化ナトリウム、水酸化カリウムなどの塩基性物質を
添加しておくことが望ましい。アルカリ性下での蒸留は
、前記の様に酸化処理を経たラクタム水溶液がすでにア
ルカリ性となつている場合は新たにアルカリを加える必
要はない。一方、アルカリを添加する場合は、たとえば
水酸化ナトリウム、水酸化カリウム、水酸化リチウム、
炭酸ナトリウム、炭酸カリウムなどの塩基性物質を添加
して常法に従つて蒸留することにより、目的とする高純
度のラクタムが得られる。この際に添加されるアルカリ
量はラクタム水溶液中のラクタムに対し0.01〜1.
0重量%になるよう選ぶことが好ましい。Additionally, if the temperature of the lactam aqueous solution is too high during treatment, side reactions are likely to occur in addition to oxidizing impurities.
On the other hand, if the temperature is too low, the impurities will not be oxidized and an excessive amount of oxidizing agent will remain, which is undesirable, so care should be taken to keep the temperature as low as possible in the range of 20 to 60°C. In addition, when the above hydrogen peroxide treatment is performed at a pH of 10 to 14, preferably 11 to 13, stronger oxidizing power is exhibited.
It is desirable to add a basic substance such as sodium hydroxide or potassium hydroxide. In distillation under alkaline conditions, if the lactam aqueous solution that has undergone the oxidation treatment is already alkaline as described above, there is no need to add a new alkali. On the other hand, when adding alkali, for example, sodium hydroxide, potassium hydroxide, lithium hydroxide,
By adding a basic substance such as sodium carbonate or potassium carbonate and distilling according to a conventional method, the desired high-purity lactam can be obtained. The amount of alkali added at this time is 0.01 to 1.0% to the lactam in the lactam aqueous solution.
It is preferable to select 0% by weight.
以上かかる構成よりなる本発明を採用することにより、
従来の方法では困難であつたアミン系の不純物を完全に
除去することができ、市販のラノタムと遜色のない高純
度のラクタムを、簡単な操作で、経済的に得ることがで
きる。By adopting the present invention having the above configuration,
Amine-based impurities, which were difficult to remove using conventional methods, can be completely removed, and high-purity lactam, which is comparable to commercially available lanotam, can be obtained economically with simple operations.
以下実施例に基づいて本発明を具体的に説明するが、本
発明は必ずしもこれらの実施例により限定されるもので
はない。The present invention will be specifically described below based on Examples, but the present invention is not necessarily limited to these Examples.
なおFB,.VBl過マンガン酸カリウム価(以下PZ
という)については以下の方法により測定した。In addition, FB,. VBl potassium permanganate value (hereinafter referred to as PZ
) was measured by the following method.
FB;ラクタム507をPH6の蒸留水50m1に溶解
し、この溶液をPH6に戻すために必要な1/50規定
の塩酸水溶液の量Meq/Kg単位で表わす。FB: The amount of 1/50 normal hydrochloric acid aqueous solution required to dissolve lactam 507 in 50 ml of distilled water at pH 6 and return the solution to pH 6. Expressed in Meq/Kg.
VB:ラクタム50fを20%の水酸化ナトリウム10
0m1に溶解し常法に従つて水蒸気蒸留を行いl/50
規定硫酸水溶液10m1中に留出させ250TI11と
する。VB: Lactam 50f 20% sodium hydroxide 10
Dissolve in 0ml and perform steam distillation according to the usual method to 1/50
It is distilled into 10 ml of normal sulfuric acid aqueous solution to give 250TI11.
次にこの水溶液を1/50規定水酸化ナトリウム水溶液
で滴定し、同様の操作を蒸留水について行いブランクを
考慮し、アンモニアに換算してPpm単位で表わす。P
Z:1%のラクタム水溶液にl/100規定過マンガン
酸カリウム水溶液1m1を添加し、その色が標準液(塩
化コバルト・6水塩3yと硫酸銅・5水塩27を11の
蒸留水に溶解した液)と同一色になるまでの時間を秒数
で表わす。実施例 1
ポリカプラミドの糸、チツプなどの屑1000yにリン
酸50yを添加し、過熱水蒸気を吹込みながら300′
Cで3時間解重合反応を行い、粗ラクタムを留出させた
。Next, this aqueous solution is titrated with a 1/50N aqueous sodium hydroxide solution, and the same operation is performed with distilled water, taking into consideration a blank, and expressed in units of Ppm in terms of ammonia. P
Z: Add 1 ml of 1/100N potassium permanganate aqueous solution to 1% lactam aqueous solution, and the color changes from standard solution (cobalt chloride hexahydrate 3y and copper sulfate pentahydrate 27 dissolved in 11 distilled water) The time it takes for the color to become the same as that of the liquid (mixed liquid) is expressed in seconds. Example 1 50 y of phosphoric acid was added to 1000 y of scraps such as polycapramide threads and chips, and the mixture was heated for 300 y while blowing superheated steam.
A depolymerization reaction was carried out at C for 3 hours, and the crude lactam was distilled off.
得られた粗ラクタム水溶液4000m1(ラクタム濃度
24.5%、ラクタム収率98.0%)を約1600m
1(ラクタム濃度約60%)に濃縮し、次いでこの濃縮
した粗ラクタム水溶液に5容量%の硫酸25.3m1を
添加して溶液をPH4に調整後、まず水を留出させた後
、続いて留出温度98〜100℃、減圧度2m77!H
gで蒸留し、ラクタム9657を得、このラクタムを留
出した水に溶解し1600m1とした(酸性下蒸留収率
98.5%)。このラクタム水溶液の400m1に20
%水酸化ナトリウム0.95m1を添加して溶液をPH
l.2に調整後、水を蒸発させ、留出温度99〜100
℃減圧度2mmHgでラクタムを留出させた。得られた
ラクタムの品質はPZ;)2500秒、VB;3.0p
pm.FB;0.003meq/Kgであり、通常市販
されているラクタムの品質がPZ:1600秒以上、V
B;2.5〜4.0ppm,.FB:0,01〜0.0
2meq/K9であるのに比較して遜色のないものであ
る。実施例 2〜4
実施例1の酸性下蒸留で得られたラクタム水溶液の残り
1200m1を400m1ずつに分離し、その各々を過
マンガン酸カリウム、過酸化水素、オゾンで酸化した。Approximately 1,600 ml of the obtained crude lactam aqueous solution (lactam concentration 24.5%, lactam yield 98.0%) was
1 (lactam concentration about 60%), then 25.3 ml of 5 volume % sulfuric acid was added to this concentrated crude lactam aqueous solution to adjust the solution to pH 4, and then water was first distilled off, and then Distillation temperature 98-100℃, degree of vacuum 2m77! H
g to obtain lactam 9657, which was dissolved in the distilled water to make 1600 ml (distillation yield under acidic conditions: 98.5%). 20 ml of this lactam aqueous solution
The solution was adjusted to pH by adding 0.95ml of % sodium hydroxide.
l. After adjusting to 2, water is evaporated and the distillation temperature is 99-100.
The lactam was distilled off at a temperature of 2 mmHg. The quality of the obtained lactam is PZ;) 2500 seconds, VB; 3.0p
pm. FB: 0.003 meq/Kg, and the quality of normally commercially available lactams is PZ: 1600 seconds or more, V
B; 2.5 to 4.0 ppm,. FB: 0.01~0.0
Although it is 2meq/K9, it is comparable. Examples 2 to 4 The remaining 1200 ml of the lactam aqueous solution obtained by distillation under acidic conditions in Example 1 was separated into 400 ml portions, each of which was oxidized with potassium permanganate, hydrogen peroxide, and ozone.
その処理液をそれぞれPHl2に調整後(過マンガン酸
カリウム酸化の場合は副生する二酸化マンガンを予め瀘
過分離しておく)、実施例1と同様にしてラクタムを留
出させた。この時の酸化条件および得られたラクタムの
品質結果を第1表に示す。第1表より、酸化処理を経る
ことによりさらにPZが良好となることがわかる。After each of the treated solutions was adjusted to PHL2 (in the case of potassium permanganate oxidation, by-product manganese dioxide was separated by filtration in advance), the lactam was distilled out in the same manner as in Example 1. The oxidation conditions at this time and the quality results of the obtained lactam are shown in Table 1. From Table 1, it can be seen that PZ becomes even better through oxidation treatment.
比較例 1
実施例1と同様にして解重合し、濃縮した粗ラクタム水
溶液400m1を酸性下蒸留をせず、単に5%過マンガ
ン酸カリウム14.4m1(添加量ラクタムに対し0.
3重量%)添加し40℃で30分間酸化後、副生二酸化
マンガンを分離し、次いで実施例1と同様にしてラクタ
ムを留出させた。Comparative Example 1 400 ml of a crude lactam aqueous solution depolymerized and concentrated in the same manner as in Example 1 was not distilled under acidic conditions, but simply 14.4 ml of 5% potassium permanganate (0.0 ml of 5% potassium permanganate (based on the amount of lactam added).
After oxidation at 40° C. for 30 minutes, the by-product manganese dioxide was separated, and then the lactam was distilled out in the same manner as in Example 1.
得られたラクタムの品質はPZ:2000秒、VB;1
1.4ppmFB;0.45meq/K9であり、実施
例1と比較するとかなり悪かつた。比較例 2・3
実施例1と同様にして解重合し、濃縮した粗ラクタム水
溶液を5%硫酸でPHl.5およびPH6.5に調整後
、酸性下蒸留を行い、得られたラグタム水溶液を実施例
1と同様にしてラクタムを留出させた。The quality of the obtained lactam is PZ: 2000 seconds, VB: 1
1.4 ppm FB; 0.45 meq/K9, which was considerably worse than in Example 1. Comparative Examples 2 and 3 A crude lactam aqueous solution depolymerized and concentrated in the same manner as in Example 1 was diluted with 5% sulfuric acid to PHL. After adjusting the pH to 5 and 6.5, distillation was performed under acidic conditions, and the resulting aqueous lactam solution was treated in the same manner as in Example 1 to distill off the lactam.
得られたラクタム品質および酸性下蒸留時のラクタム収
率を第2表に示す。第2表より、酸性下蒸留時のPHが
2以下の場合は精製効果は良好で、高純度のラクタムが
得られるが、ラクタムの収率が低い。The quality of the lactam obtained and the lactam yield upon distillation under acidic conditions are shown in Table 2. From Table 2, when the pH during distillation under acidic conditions is 2 or less, the purification effect is good and highly pure lactam can be obtained, but the yield of lactam is low.
Claims (1)
媒の存在下に、熱解重合して得られる粗ε−カプロラク
タムを精製するに際し、該粗ε−カプロラクタムの水溶
液をpH2〜6の酸性下で蒸留する工程およびpH10
〜14のアルカリ性下で蒸留する工程を経ることを特徴
とするε−カプロラクタムの精製方法。 2 ポリカプラミドをリン酸系触媒またはアルカリ系触
媒の存在下に、熱解重合して得られる粗ε−カプロラク
タムを精製するに際し、該粗ε−カプロラクタムの水溶
液をpH2〜6の酸性下で蒸留し、次いで酸化剤で処理
した後、pH10〜14のアルカリ性下で蒸留すること
を特徴とするε−カプロラクタムの精製方法。[Scope of Claims] 1. When purifying crude ε-caprolactam obtained by thermally depolymerizing polycapramide in the presence of a phosphoric acid catalyst or an alkaline catalyst, an aqueous solution of the crude ε-caprolactam is purified to a pH of 2 to 6. Distillation process under acidic conditions and pH 10
A method for purifying ε-caprolactam, which comprises the steps of distilling under alkaline conditions. 2. When purifying crude ε-caprolactam obtained by thermally depolymerizing polycapramide in the presence of a phosphoric acid catalyst or an alkaline catalyst, an aqueous solution of the crude ε-caprolactam is distilled under acidic conditions of pH 2 to 6, A method for purifying ε-caprolactam, which comprises treating it with an oxidizing agent and then distilling it under alkaline conditions with a pH of 10 to 14.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP1800378A JPS5943945B2 (en) | 1978-02-17 | 1978-02-17 | ε↓−Method for purifying caprolactam |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP1800378A JPS5943945B2 (en) | 1978-02-17 | 1978-02-17 | ε↓−Method for purifying caprolactam |
Publications (2)
Publication Number | Publication Date |
---|---|
JPS54109992A JPS54109992A (en) | 1979-08-29 |
JPS5943945B2 true JPS5943945B2 (en) | 1984-10-25 |
Family
ID=11959510
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP1800378A Expired JPS5943945B2 (en) | 1978-02-17 | 1978-02-17 | ε↓−Method for purifying caprolactam |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPS5943945B2 (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH025735U (en) * | 1988-06-24 | 1990-01-16 |
Families Citing this family (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE4407222A1 (en) * | 1994-03-04 | 1995-09-07 | Basf Ag | Process for the recovery of caprolactam from oligo and / or polymers of caprolactam |
PL2935210T3 (en) * | 2012-12-19 | 2017-05-31 | Basf Se | Process for the preparation of purified caprolactam from the beckman rearrangement of cyclohexanoxim |
-
1978
- 1978-02-17 JP JP1800378A patent/JPS5943945B2/en not_active Expired
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH025735U (en) * | 1988-06-24 | 1990-01-16 |
Also Published As
Publication number | Publication date |
---|---|
JPS54109992A (en) | 1979-08-29 |
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