KR100315507B1 - Purification method of recovered caprolactam - Google Patents
Purification method of recovered caprolactam Download PDFInfo
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- KR100315507B1 KR100315507B1 KR1019950039334A KR19950039334A KR100315507B1 KR 100315507 B1 KR100315507 B1 KR 100315507B1 KR 1019950039334 A KR1019950039334 A KR 1019950039334A KR 19950039334 A KR19950039334 A KR 19950039334A KR 100315507 B1 KR100315507 B1 KR 100315507B1
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- C—CHEMISTRY; METALLURGY
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- C07D201/00—Preparation, separation, purification or stabilisation of unsubstituted lactams
- C07D201/16—Separation or purification
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- C—CHEMISTRY; METALLURGY
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- C07D201/00—Preparation, separation, purification or stabilisation of unsubstituted lactams
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Description
본 발명은 회수 카프로락탐의 정제방법에 관한 것으로서, 보다 구체적으로는 나일론6를 해중합하여 카프로락탐을 회수하는 과정에서 유분이 부착된 원사등을 해중합함으로써 발생되는 불순물들을 제거하여 고순도의 회수 카르로락탐을 수득하는 방법에 관한 것이다.The present invention relates to a method for purifying recovered caprolactam, and more particularly, to remove impurities generated by depolymerization of an oil-coated yarn or the like in the process of depolymerizing nylon 6 to recover caprolactam, thereby recovering high-purity carrolactam. To a method for obtaining the same.
나일론6는 부식성이 없으므로 매립하여 폐기할 경우 분해되지 않고 그대로 축적되므로 토양을 황폐화시킬 우려가 있고, 소각폐기하는 경우에도 대기오염등의 소지가 있으므로, 폐기되는 나일론6를 재활용하기 위한 가장 효과적인 방법은 해중합하여 회수카프로락탐으로 재생하는 방법이다.Since nylon 6 is not corrosive, it is not decomposed when landfilled and disposed of. Therefore, the soil may be depleted, and even in the case of incineration, there is a possibility of air pollution. It depolymerizes and regenerates with a caprolactam.
종래, 나일론6의 해중합에 관하여 일본특공소 52-31877호의 공보 등에 제시되어 있으나, 이러한 종래 방법에 의하면 유분이 부착된 원사나 기타 각종 형태의 나일론6의 웨이스트 해중합시 발생되는 불순물이 다양하게 존재하므로 고분자 응집제 처리만으로는 회수 카프로락탐의 물성이 양호해지지 않는 것이 문제점으로 남아 있다.Conventionally, the depolymerization of nylon 6 is disclosed in Japanese Unexamined Patent Publication No. 52-31877, etc., but according to the conventional method, impurities generated during waste depolymerization of oil-bearing yarn or other various types of nylon 6 are present. It remains a problem that the physical properties of the recovered caprolactam are not improved only by treatment with the polymer flocculant.
회수카프로락탐의 물성이 새 카프로락탐(virgin caprolactam) 보다 크게 저하될 경우, 이를 재사용한 수지나 얀(yarn) 등에서 문제를 일으키므로, 사용할 수 없거나 또는 사용량을 극히 소량밖에 할 수 없으므로, 회수카프로락탐의 물성을 개선해야할 필요성이 있다,If the physical properties of the recovered caprolactam are significantly lower than that of the new caprolactam, it may cause problems in the reused resin or yarn, and thus cannot be used or use only a very small amount of recovered caprolactam. Needs to improve their properties,
따라서 본 발명은 이러한 회수카프로락탐을 보다 많이 재활용 가능하도록, 회수카프로락탐의 물성을 향상시키기 위한 정제방법을 제공하는 것을 목적으로 한다.Therefore, an object of the present invention is to provide a purification method for improving the physical properties of the recovered caprolactam, so that the recovered caprolactam can be recycled more.
상기한 목적을 달성하기 위한 본 발명에 의하면, 나일론-6 웨이스트(waste)를 해중합하여 얻어지는 카프로락탐 수용액에 포함된 불순물을 제거,여과하므로써 고순도의 카프로락탐을 얻는 회수카프로락탐의 정제방법에 있어서,According to the present invention for achieving the above object, in the method for purifying recovered caprolactam to obtain a high-purity caprolactam by removing and filtering impurities contained in the aqueous solution of caprolactam obtained by depolymerizing nylon-6 waste (waste),
해중합된 10∼60 중량% 카프로락탐 수용액에 5중량% 과망간산칼륨 수용액을 5∼10 중량부 첨가하여 불순물을 산화시켜 1차로 제거, 여과한 다음, 분자량 1000만∼1600만의 폴리아크릴아미드 고분자응집제를 첨가하여 불순물을 2차로 제거, 여과하고, 0.5∼2 중량부의 수산화나트륨을 첨가, 증류하여 고순도의 카프로락탐을 얻는 일련의 연속공정을 거치는 것을 특징으로 하는 회수카프로락탐의 정제방법이 제공된다.5 to 10 parts by weight of a 5% by weight aqueous solution of potassium permanganate is added to the depolymerized 10 to 60% by weight aqueous solution of caprolactam, followed by oxidizing impurities to remove the primary, filtered, and then a polyacrylamide polymer coagulant having a molecular weight of 10 to 16 million. There is provided a method for purifying recovered caprolactam, characterized in that the impurities are removed secondly, filtered, and 0.5-2 parts by weight of sodium hydroxide is added and distilled to obtain a high-purity caprolactam.
보다 상세하게 설명하면 본 발명은 원사, 칩, 스파게티(spagetti), 성형품, 올리고머(oligomer)등 다양한 나일론6의 웨이스트를 통상의 방법에 따라 260∼350℃에서 인산을 첨가하여 가수분해시켜 카프로락탐 10∼60 중량% 수용액을 제조하고, 다음과 같은 새로이 개발된 공정, 즉 카프로락탐 수용액에 과망간산칼륨을 5 중량% 수용액으로 5∼10 중량부를 첨가, 30분 이상 교반시켜 불순물을 산화시키고,산화반응후 발생하는 고형물을 메쉬필터(mesh filter)나 그밖의 여과방법으로 1차 여과하여 제거한 후, 분자량 1,000만∼1,600만의 폴리아크릴아미드 고분자 응집제를 0.2 중량% 수용액으로 1∼3 중량부 투입하고 교반하여 고형물 형태로 생성된 불순물과 유상물(油狀物) 및 잔류 망간화합물을 응집하고 메쉬필터나 그밖의 여과방법으로 2차 여과제거하는 공정을 수행한 다음, 이후 통상의 농축, 수산화나트륨(NaOH) 첨가, 증류등의 방법을 거쳐 물성이 우수한 회수 카프로락탐을 얻는 정제방법에 관한 것이다.In more detail, the present invention is a caprolactam 10 by hydrolyzing a variety of nylon 6 waste, such as yarn, chips, spaghetti, molded articles, oligomers by adding phosphoric acid at 260 ~ 350 ℃ according to a conventional method To prepare an aqueous solution of ˜60% by weight, add 5-10 parts by weight of potassium permanganate as a 5% by weight aqueous solution to a caprolactam aqueous solution, and stir for 30 minutes or more to oxidize impurities, and after oxidation The resulting solids were first filtered off by a mesh filter or other filtration method, and then 1 to 3 parts by weight of a polyacrylamide polymer coagulant having a molecular weight of 10 to 16 million was added to a 0.2% by weight aqueous solution, followed by stirring. Aggregate impurities, oily substances, and residual manganese compounds in the form, and perform secondary filtration and removal using a mesh filter or other filtration method. Well, the present invention relates to a purification method for obtaining a recovered caprolactam having excellent physical properties through usual concentration, sodium hydroxide (NaOH) addition, distillation, and the like.
이와 같이 본 발명에서는 복합적인 일련의 연속적인 정제처리를 함으로서 상승효과를 기대할 수 있도록 구성되어 있다. 각 공정 별로 상세히 설명하면 다음과 같다.As described above, in the present invention, a synergistic effect can be expected by performing a series of complex purification processes. Detailed description of each process is as follows.
먼저 과망간산칼륨에 의한 산화처리는 아래 반응식과 같이 과망간산칼륨의 망간의 산화수가 바뀌면서 불순물을 산화시킬 수 있는 발생기 산소를 방출시켜, 방출된 발생기 산소가 카프로락탐 수용액중의 불순물들의 작용기를 산화시킴으로써 불순물의 제거를 가능하게 된다. 산화된 불순물은 카프로락탐 수용액에서 석출되거나 증류공정에서 제거된다.First, the oxidation treatment with potassium permanganate releases generator oxygen capable of oxidizing impurities as the oxidation number of potassium permanganate changes, and the released generator oxygen oxidizes functional groups of impurities in the caprolactam aqueous solution. Removal is possible. Oxidized impurities are precipitated in aqueous caprolactam or removed in a distillation process.
과망간산칼륨은 5 중량% 수용액으로 1∼10 중량부를 투입하여 30분 이상 교반시키는데 그 투입량이 5 중량부 보다 낮은 경우에는 불순물을 산화시키는 효과가 미미하며, 10 중량부를 초과하는 경우에는 과망간산칼륨의 용해도 감소로 수용액중에서 침전된 상태로 남아 있을 수 있으므로 상기한 범위내로 유지시키는 것이 바람직하다.Potassium permanganate is added in an amount of 1 to 10 parts by weight in a 5% by weight aqueous solution and stirred for 30 minutes or more. When the amount is lower than 5 parts by weight, the effect of oxidizing impurities is insignificant. It is preferable to keep within the above range as the reduction may remain precipitated in aqueous solution.
둘째로 이러한 산화반응이 끝난후 KMnO4나 MnO2가 남아 있을 경우 산화반응이 계속 진행될 수도 있어 회수카프로락탐에 영향을 줄 수 있으므로, 1차 여과를 실시하여 산화반응후 석출된 물질들과 함께 제거하여 준다. 1차여과에서는 뒤에 2차 여과가 있으므로 고형물의 완전제거가 필요없으므로 메쉬 필터등을 써서 간단하게 제거해 주는 것이 좋다.Secondly, if KMnO 4 or MnO 2 is left after the oxidation reaction, the oxidation reaction may be continued and may affect the recovered caprolactam. Give it. In the first filtration, there is a second filtration at the back, so it is not necessary to completely remove the solids.
셋째, 폴리아크릴아미드 고분자응집제를 투입하면 부유물이나 유상 혼합물 형태의 불순물이나, 산화반응후의 미세한 망간화합물을 포집하여 응집물이 형성된다. 이 때 분자량이 1,000만 이하의 폴리아크릴아미드는 응집체 형성이 미약하므로 이의 제거가 용이하지 않으므로 부적합하다. 또한 응집시 교반속도 60 RPM 이하의 약 교반을 해줌으로 해서 응집체를 깨뜨리지 않으면서 계내의 불순물을 효과적으로 포집시켜 주는 것이 중요하다. 본 방법에서 이용하기 적합한 고분자응집제는 분자량 1,000만 ∼ 1,600만, 더욱 좋기로는 분자량 1,400만 ∼ 1,550만의 폴리아크릴아미드 고분자응집제이다.Third, when the polyacrylamide polymer coagulant is added, aggregates are formed by trapping impurities in the form of suspended solids or oily mixtures or fine manganese compounds after the oxidation reaction. At this time, polyacrylamide having a molecular weight of 10 million or less is not suitable because its formation is not easy because its removal is not easy. In addition, it is important to effectively collect impurities in the system without breaking the agglomerates by performing agitation at a stirring speed of 60 RPM or less. Polymer coagulants suitable for use in the present method are polyacrylamide polymer coagulants having a molecular weight of 10 million to 16 million, more preferably 14 million to 15 million molecular weight.
넷째, 이러한 응집물을 메쉬 필터 등으로 여과하여 불순물과 응집체를 동시에 제거해 준다. 이 여과공정에서는 비교적 크고 강도가 있는 응집체의 형성으로 메쉬 필터를 이용한 간단한 단순여과만으로도 충분히 제거가 가능하며, 그 이유는 미세한 망간화합물이 응집체에 포함되고, 분자량이 큰 고분자응집제를 사용하기 때문으로 판단된다.Fourth, the aggregates are filtered through a mesh filter to remove impurities and aggregates at the same time. In this filtration process, the formation of a relatively large and cohesive aggregate can be sufficiently removed by simple simple filtration using a mesh filter because the fine manganese compound is included in the aggregate and a high molecular weight coagulant is used. do.
따라서 이러한 처리공정을 순차적으로 거치면서 산화처리효과, 부유 불순물의 포집효과, 산화반응물질의 제거등 각각의 효과가 서로 상승작용을 일으켜, 용이한 공정으로 고품질의 회수카프로락탐을 얻을 수 있게 된다.Therefore, the oxidative treatment effect, the trapping effect of suspended impurities, the removal of the oxidizing reactant, and the like effect the synergistic effects with each other, and the high quality recovered caprolactam can be obtained in an easy process.
이하, 본 발명을 실시예에 의해 더욱 구체적으로 설명하겠는 바, 본 발명은 후술되는 실시예에 의해 한정되는 것은 아니다.Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to the Examples described below.
《실시예 1》<< Example 1 >>
방사유제가 1% 부착된 나일론6(폴리카프로락탐) 원사 100 중량부와 나일론6 칩 100 중량부를 반응기에 넣고, 인산 2.0 중량부와 물 700 중량부를 투입한 후, 290℃에서 3시간 해중합시키면서 유출되는 증기(Vapor)를 응축하여 25%의 미정제 카프로락탐(crude caprolactam) 수용액을 얻었다, 이 수용액에 5% 과망간산칼륨 수용액 8 중량부를 투입하고 30분간 교반하면서 반응을 시킨 후, 40μ0의 메쉬 필터로 여과하여 용액중 고형성분을 제거하였다. 다음, 분자량 1,500만의 폴리아크릴아미드 고분자응집제 0,2% 수용액을 2 중량부첨가한 후 30분간 임펠러타입 교반기로 교란속도 60 RPM 이하로 약하게 교반하면서 응집체를 형성시킨다. 형성된 응집물을 10μ0메쉬 필터로 여과, 제거한 후 맑은 용액을 얻었다.100 parts by weight of nylon 6 (polycaprolactam) yarn with 1% of spinning oil and 100 parts by weight of nylon 6 chip were placed in a reactor, 2.0 parts by weight of phosphoric acid and 700 parts by weight of water were added, followed by depolymerization at 290 ° C. for 3 hours. After condensing the vapor (Vapor) to obtain a 25% crude caprolactam aqueous solution, 8 parts by weight of 5% aqueous potassium permanganate solution was added to the aqueous solution and reacted while stirring for 30 minutes, the mesh filter of 40μ 0 The solid component in the solution was removed by filtration. Next, after adding 2 parts by weight of an aqueous solution of 0,2% of a polyacrylamide polymer coagulant having a molecular weight of 15 million, agglomerates are formed while stirring gently at a disturbance rate of 60 RPM or less with an impeller stirrer for 30 minutes. The formed aggregate was filtered and removed with a 10 mu 0 mesh filter to obtain a clear solution.
수득 용액을 증류장치에 넣고 80% 농도가 될 때까지 농축후, 1 중량부의 수산화나트륨을 첨가하고, 나머지 물을 증발시키고, 카프로락탐을 증류하여 회수하였다. 이러한 회수카프로락탐의 수율, PZ치와 PM치를 다음과 같은 방법으로 측정하였다. 측정결과는 하기 표 1에 제시된다.The obtained solution was placed in a distillation apparatus, concentrated to 80% concentration, 1 part by weight of sodium hydroxide was added, the remaining water was evaporated, and caprolactam was recovered by distillation. The yield, PZ value and PM value of the recovered caprolactam were measured by the following method. The measurement results are shown in Table 1 below.
◎ PZ치 : 0.01N 과망간산칼륨 수용액 1㎖를 회수카프로락탐의 1% 수용액 100㎖에 첨가하여 비색관에 넣은 후, 비색관의 표준액과 동일한 색상이 될 때까지의 시간을 초수로 표시한다. 이때, 표준용액은 COCl2·6H2O 3g과 CuSO4·5H2O 2g을 물 1ℓ에 용해하여 제조함.◎ PZ value: 1 ml of 0.01 N potassium permanganate aqueous solution is added to 100 ml of 1% aqueous solution of recovered caprolactam and placed in a color tube, and the time until the same color as the standard solution of the color tube is expressed in seconds. In this case, the standard solution is prepared by dissolving C O Cl 2 · 6H 2 O 3g and CuSO 4 · 5H 2 O 2g in 1ℓ of water.
◎ PM치 : 0.01N 과망간산칼륨 수용액 1㎖를 회수카프로락탐의 3% 수용액 100㎖에 첨가하여 비색관에 넣은 후, 비색관의 표준액과 동일한 색상이 될 때까지의 시간을 초수로 표시한다. 이 때, 표준용액 은 COCl2·6H2O 3g과 0.1% K2CrO4용액 45㎖를 물 1ℓ에 가하여 제조함.◎ PM value: 1 ml of 0.01 N aqueous potassium permanganate solution is added to 100 ml of a 3% aqueous solution of recovered caprolactam and put into a color tube, and the time until the same color as the standard solution of the color tube is expressed in seconds. At this time, the standard solution was prepared by adding 3 g of C O Cl 2 · 6H 2 O and 45 ml of 0.1% K 2 CrO 4 solution to 1 liter of water.
《 실시예 2 》<< Example 2 >>
실시예 1에서 나일론6 원사만 200 중량부 사용하고, 5% 과망간산칼륨 수용액 10 중량부를 사용하고, 고분자응집제 0.2% 수용액을 3 중량부 첨가한 것을 제외하고는 실시예 1과 동일하게 실시하였다.Example 1 was carried out in the same manner as in Example 1 except that only 200 parts by weight of nylon 6 yarn, 10 parts by weight of 5% aqueous potassium permanganate solution, and 3 parts by weight of 0.2% aqueous solution of polymer coagulant were added.
《 실시예 3 》<< Example 3 >>
실시예 1에서 나일론6 칩만 200 중량부 사용하고, 5% 과망간산칼륨 수용액 5 중량부를 사용한 것을 제외하고는 실시예 1과 동일하게 실시하였다.Except for using 200 parts by weight of nylon 6 chip in Example 1, 5 parts by weight of 5% aqueous potassium permanganate solution was carried out in the same manner as in Example 1.
《 실시예 4 》<< Example 4 >>
실시예 1에서 나일론6 원사 200 중량부, 칩 50 중량부와, 나일론 칩 제조시 칩추출공정의 추출수로부터 카프로락탐을 증류, 회수한 뒤 남는 올리고머 잔류물 중량부를 사용한 것을 제외하고는 실시예 1과 동일하게 실시하였다.Except that in Example 1 200 parts by weight of nylon 6 yarn, 50 parts by weight of chip, and the weight of oligomer residues remaining after distilling and recovering caprolactam from the extraction water of the chip extraction process in the manufacture of nylon chips The same procedure was followed.
《 비교예 1 》<< comparative example 1 >>
실시예1에서 5% 과망간산칼륨 수용액을 8 중량부 투입, 30분 교반까지는 동일하고, 이어서 바로 수용액을 중류장치에 넣고, 80% 농축후, 1 중량부 수산화나트륨을 넣고, 물증발후, 카프로락탐을 증류하여 회수하였다.In Example 1, 8 parts by weight of a 5% aqueous potassium permanganate solution was added and the same until 30 minutes of stirring. Then, the aqueous solution was immediately added to a midstream apparatus, after 80% concentration, 1 part by weight of sodium hydroxide was added, and after evaporation of water, caprolactam Was recovered by distillation.
《 비교예 2 》<< comparative example 2 >>
실시예 1에서 해중합하여 얻어진 25%의 미정제 카프로락탐 수용액에 바로 분자량 100만의 폴리아크릴아미드 고분자응집제 0.2% 수용액을 2 중량부 첨가한 후, 30분간 약하게 교반하면서 응집체를 형성시킨다. 형성된 응집물을 10μ0메쉬 필터로 여과한 후, 증류장치에 넣고 80% 농도가 될 때까지 농축후, 1 중량부의 수산화 나트륨을 첨가하고, 나머지 물을 증발시키고, 카프로락탐을 증류하여 회수하였다.2 parts by weight of a 0.2% aqueous solution of a polyacrylamide polymer coagulant having a molecular weight of 1 million is immediately added to a 25% crude caprolactam aqueous solution obtained by depolymerization in Example 1, and then aggregates are formed with gentle stirring for 30 minutes. The formed aggregate was filtered through a 10 mu 0 mesh filter, placed in a distillation apparatus, concentrated to 80% concentration, 1 part by weight of sodium hydroxide was added, the remaining water was evaporated, and caprolactam was recovered by distillation.
《 비교예 3》<< comparative example 3 >>
방사유제가 1% 부착된 나일론6 원사 200 중량부, 85% 인산 20 중량부를 넣고, 290℃에서 질소하에서 2시간 해중합후, 5 토르 감압으로 30% 미정제 카프로락탐 수용액을 얻었다. 이에 수산화나트륨을 첨가하여 pH를 7.5로 조정하여 2시간 방치하였다. 이어서, 분자량 약 50만의 폴리아크릴아미드계 고분자응집제 0.1% 수용액을 28 중량부 넣고 2시간 방치후, 표충부에 부상된 응집물을 활성백토충이 형성된 여과장치로 1차 여과하고, 활성탄이 충진된 컬럼(Column)에 2차 여과후, 용액을 80%로 농축하고, 1 중량부의 수산화 나트륨을 투입후 나머지 물을 증발시키고, 카프로락탐을 증류하여 회수하였다.200 parts by weight of nylon 6 yarn with 1% of spinning agent and 20 parts by weight of 85% phosphoric acid were added, and after depolymerization at 290 ° C. for 2 hours under nitrogen, a 30% crude caprolactam aqueous solution was obtained under reduced pressure of 5 Torr. Sodium hydroxide was added thereto to adjust the pH to 7.5 and left for 2 hours. Subsequently, 28 parts by weight of a 0.1% aqueous solution of a polyacrylamide-based polymer coagulant having a molecular weight of about 500,000 was left for 2 hours, and then the aggregates floating on the worms were first filtered through a filter device in which an active earthworm was formed and a column filled with activated carbon ( After secondary filtration in a column), the solution was concentrated to 80%, 1 part by weight of sodium hydroxide was added, the remaining water was evaporated, and caprolactam was recovered by distillation.
※ PZ치나 PM치는 카프로락탐 물성의 대표적인 측정법으로, 높을수록 물성이 양호함※ PZ value and PM value are representative measuring methods of caprolactam property, and the higher the property is, the better
상기 표 1로부터 알 수 있는 바와 같이 해중합된 카프로락탐의 정제는 과망간산칼륨으로 불순물을 산화시켜 1차 제거, 여과하는 공정과 고분자응집제로 불순물을 2차 제거, 여과하는 공정이 일련의 연속공정으로 수행되었을 때 고순도의 카프로락탐을 얻을 수 있다.As can be seen from Table 1, the depolymerized caprolactam is subjected to a first step of oxidizing impurities with potassium permanganate, and a second step of removing and filtering impurities with a polymer coagulant. When the high purity caprolactam can be obtained.
그 이유는 과망간산칼륨으로 불순물을 산화시켜 1차 제거, 여과하는 공정에서 카프로락탐에 포함되어 있는 망간화합물을 2차 여과시 고분자응집제로 포집하여 응집물의 형태로 제거,여과시킬 수 있는데 반하여, 고분자응집제를 먼저 처리하면 망간화합물이 잘 제거되지 않고 제거되지 않은 망간화합물은 카프로락탐을 분해시켜 수율을 떨어뜨리기 때문이다.The reason is that in the process of oxidizing impurities with potassium permanganate to remove and filter the primary, the manganese compounds contained in caprolactam can be collected as a polymer coagulant during the second filtration and removed and filtered in the form of aggregates. This is because when the first treatment of the manganese compound is not removed well, the manganese compound that is not removed decomposes the caprolactam and lowers the yield.
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