JPH08109167A - Purification of n-methyl-2-pyrrolidone - Google Patents
Purification of n-methyl-2-pyrrolidoneInfo
- Publication number
- JPH08109167A JPH08109167A JP24543494A JP24543494A JPH08109167A JP H08109167 A JPH08109167 A JP H08109167A JP 24543494 A JP24543494 A JP 24543494A JP 24543494 A JP24543494 A JP 24543494A JP H08109167 A JPH08109167 A JP H08109167A
- Authority
- JP
- Japan
- Prior art keywords
- distillation column
- pyrrolidone
- nmp
- methyl
- column
- 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.)
- Granted
Links
Landscapes
- Pyrrole Compounds (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明はＮ−メチル−２−ピロリ
ドン（以下、ＮＭＰと略す。）の精製方法に関するもの
である。詳しくは、熱効率よくＮＭＰ（ａ）とＮＭＰよ
り比揮発度の小さい有機物（ｂ）を含む水溶液からＮＭ
Ｐを精製して回収する方法に関するものである。このＮ
ＭＰは、トリクレンのような塩素化炭化水素溶剤の代替
として使用される金属洗浄剤として有用である。FIELD OF THE INVENTION The present invention relates to a method for purifying N-methyl-2-pyrrolidone (hereinafter abbreviated as NMP). Specifically, from an aqueous solution containing NMP (a) and an organic substance (b) having a smaller specific volatility than NMP with good thermal efficiency, NM
The present invention relates to a method of purifying and recovering P. This N
MP is useful as a metal detergent used as a replacement for chlorinated hydrocarbon solvents such as trichlene.
【０００２】[0002]
【従来の技術】ＮＭＰを製造する方法としては、γ−ブ
チロラクトンとモノメチルアミンとを反応させる方法
（特公昭４９−２０５８５号、同４９−２０５８６号、
同５１−４２１０７号、特開平１−１９０６６７号参
照）や２−ピロリドンとメタノールとを反応させる方法
（特公昭５７−４５２１８号参照）が知られている。2. Description of the Related Art As a method for producing NMP, a method of reacting .gamma.-butyrolactone with monomethylamine (Japanese Patent Publication Nos. 49-20585 and 49-20586,
51-42107, JP-A-1-190667) and a method of reacting 2-pyrrolidone with methanol (see JP-B-57-45218).
【０００３】この反応生成物には、Ｎ−メチル−２−ピ
ロリドン、水の外にＮ−メチル−２−ピロリドンよりも
比揮発度の小さい（沸点が高い）、有機物、例えば２−
ピロリドンを含む水溶液（通常、ＮＭＰよりも比揮発度
の小さな有機物を少量、好ましくは３重量％以下含有
し、且つ水を５重量％以上、好ましくは１０〜５０重量
％の範囲で含有するＮＭＰ水溶液である。）であるの
で、反応生成物より水およびかかる比揮発度の小さい有
機物を除いて高純度（９９重量％以上）のＮ−メチル−
２−ピロリドンを得るという精製工程が必要とされ、通
常、工業的な規模においては蒸留によって精製されてい
る。The reaction products include N-methyl-2-pyrrolidone, water, as well as N-methyl-2-pyrrolidone having a smaller specific volatility (higher boiling point) than N-methyl-2-pyrrolidone, organic substances such as 2-.
Aqueous solution containing pyrrolidone (usually an NMP aqueous solution containing a small amount of organic matter having a smaller specific volatility than NMP, preferably 3% by weight or less and water in an amount of 5% by weight or more, preferably 10 to 50% by weight). Therefore, N-methyl- of high purity (99% by weight or more) is excluded, except for water and organic matter having a smaller relative volatility than the reaction product.
A purification step of obtaining 2-pyrrolidone is required and is usually purified by distillation on an industrial scale.
【０００４】例えば特公昭５１−４２１０７号公報に
は、反応帯域から得られた反応生成物を蒸留塔に供給
し、未反応のモノアルキルアミンと水の一部とを塔頂か
ら留出させて反応帯域に循環し、０．５〜２．０モル倍
の水を含有するピロリドン類を塔底から回収し、これを
脱水蒸留塔に導入して減圧下に蒸留を行ない水を除去
し、脱水したピロリドン類を更により低い減圧下で蒸留
して高沸点物を塔底から除去して精製したピロリドン類
を得ることが開示されている。For example, in Japanese Patent Publication No. 51-42107, the reaction product obtained from the reaction zone is fed to a distillation column, and unreacted monoalkylamine and a part of water are distilled from the top of the column. Pyrrolidones that circulate in the reaction zone and contain 0.5 to 2.0 moles of water are recovered from the bottom of the tower, and this is introduced into a dehydration distillation tower and distilled under reduced pressure to remove water and dehydrate. It is disclosed that the above pyrrolidones are distilled under a further lower pressure to remove high-boiling substances from the bottom of the column to obtain purified pyrrolidones.
【０００５】又、特開昭６１−１９１６７３号公報に
は、不純物として芳香族化合物及び水に不溶性の有機化
合物を含有する粗Ｎ−メチルピロリドンを蒸留精製する
にあたり、 該粗Ｎ−メチルピロリドンを第１蒸留塔において、
水を塔底液中の水分濃度が４０重量％以上になる量存在
させ、且つ５００ｍｍＨｇ以上の圧力下で蒸留するこ
と、In Japanese Patent Laid-Open No. 61-191673, a crude N-methylpyrrolidone is purified by distillation when crude N-methylpyrrolidone containing an aromatic compound as an impurity and an organic compound insoluble in water is purified by distillation. In one distillation column,
Distilling water in an amount such that the water concentration in the bottom liquid is 40% by weight or more and under a pressure of 500 mmHg or more,
【０００６】 該第１蒸留塔の塔頂から芳香族化合
物、水に不溶性の有機化合物及び水を含有する第１の留
出液を留出させること、 該第１蒸留塔の塔底からＮ−メチルピロリドン及び
水を含有する第１の缶出液を得、それを第２蒸留塔に供
給すること、 該第２蒸留塔を減圧下で蒸留すること、Distilling a first distillate containing an aromatic compound, a water-insoluble organic compound and water from the top of the first distillation column, and N − from the bottom of the first distillation column. Obtaining a first bottoms solution containing methylpyrrolidone and water, feeding it to a second distillation column, distilling the second distillation column under reduced pressure,
【０００７】 該第２蒸留塔の塔頂から水からなる第
２の留出液を留出させ、その少なくとも一部を上記第１
蒸留塔に循環させること、及び 該第２蒸留塔の塔底から精製Ｎ−メチルピロリドン
からなる第２の缶出液を得ること、を特徴とするＮ−メ
チルピロリドンの精製方法が開示されている。A second distillate made of water is distilled from the top of the second distillation column, and at least a part of the second distillate is distilled from the first distillate.
Disclosed is a method for purifying N-methylpyrrolidone, which comprises circulating it to a distillation column and obtaining a second bottoms liquid comprising purified N-methylpyrrolidone from the bottom of the second distillation column. .
【０００８】更に、特開平１−１９０６６７号公報に
は、反応生成液を三基のオルダーショー蒸留塔を組み合
わせ、第一蒸留塔では水及び過剰分のモノメチルアミン
の大部分を塔頂に抜き出し、缶出液を第二蒸留塔でさら
に水を分離した後、第三蒸留塔で精製蒸留し中段側留分
からＮ−メチル−２−ピロリドンを抜き出し、純度が９
９．８６％、γ−ブチロラクトンの含有率が０．０３
％、色相がＡＰＨＡ１０のＮＭＰ製品を得ることが開示
されている。Further, in JP-A-1-190667, the reaction product liquid is combined with three Oldershaw distillation columns, and in the first distillation column, most of water and excess monomethylamine are withdrawn to the top of the column, and The effluent was further separated in the second distillation column to separate water, and then purified and distilled in the third distillation column to extract N-methyl-2-pyrrolidone from the middle-stage fraction, and the purity was 9%.
9.86%, γ-butyrolactone content 0.03
%, An NMP product having a hue of APHA10 is disclosed.
【０００９】[0009]
【発明が解決しようとする課題】従来の工業規模の連続
蒸留によってＮＭＰを精製し回収するには、第１蒸留塔
で水を主成分とする軽沸成分を塔頂より留出させて分離
し、ＮＭＰの同伴ロスを最少に抑えるため該留出物中の
ＮＭＰ濃度は極力小さく、好ましくは１重量％以下にな
るように還流をかけて蒸留する。さらに別の第２蒸留塔
で高沸成分とＮＭＰとを分離し、製品として純度の高い
ＮＭＰを塔頂もしくは側流より留出させることが有効で
あった。In order to purify and recover NMP by conventional industrial scale continuous distillation, a light-boiling component containing water as a main component is distilled from the top of the first distillation column and separated. In order to minimize the entrainment loss of NMP, the NMP concentration in the distillate is distilled as it is refluxed so that it is as low as possible, preferably 1% by weight or less. It was effective to separate the high boiling point component and NMP in another second distillation column and distill NMP having a high purity as a product from the top or side stream of the column.
【００１０】しかし、これらの精製方法では蒸留塔での
熱利用効率が悪く、熱源用役費が多大であった。本発明
は、γ−ブチロラクトンとモノメチルアミンとを反応さ
せて得られたＮ−メチル−２−ピロリドン反応生成液、
２−ピロリドンとメタノールとを反応させて得られたＮ
−メチル−２−ピロリドン反応生成液から熱効率よく、
かつ、色相の優れたＮＭＰを高純度に取り出す精製方法
の提供を目的とする。However, in these refining methods, the heat utilization efficiency in the distillation column was poor, and the utility cost for the heat source was large. The present invention provides a reaction product liquid of N-methyl-2-pyrrolidone obtained by reacting γ-butyrolactone with monomethylamine,
N obtained by reacting 2-pyrrolidone with methanol
-Methyl-2-pyrrolidone reaction product solution with high thermal efficiency,
Moreover, it is an object of the present invention to provide a purification method for extracting NMP having an excellent hue with high purity.
【００１１】[0011]
【課題を解決するための手段】本発明は、Ｎ−メチル−
２−ピロリドン（ａ）とＮ−メチル−２−ピロリドンよ
り比揮発度の小さい有機物（ｂ）を含む水溶液を蒸留し
て水と該有機物をほとんど含まないＮ−メチル−２−ピ
ロリドンを製造する方法において、 該水溶液を第１蒸留塔に供給して、塔頂から水とＮ
−メチル−２−ピロリドンを留出し、その一部を分縮さ
せて第１蒸留塔へ還流として戻し、残りを凝縮すること
なく第２蒸留塔の上部に気相状態で供給すること、The present invention provides N-methyl-
Method for producing N-methyl-2-pyrrolidone containing almost no water and organic matter by distilling an aqueous solution containing 2-pyrrolidone (a) and an organic matter (b) having a relative volatility lower than that of N-methyl-2-pyrrolidone In, the aqueous solution was supplied to the first distillation column, and water and N
Distilling out methyl-2-pyrrolidone, decomposing a part of it and returning it to the first distillation column as reflux, and supplying the rest in the vapor phase state to the upper part of the second distillation column without condensing.
【００１２】 第１蒸留塔の塔底からＮ−メチル−２
−ピロリドン（ａ）とＮ−メチル−２−ピロリドンより
比揮発度の小さな有機物（ｂ）の混合物を抜き出し、第
２蒸留塔の下部に液相状態で供給すること 第２蒸留塔の塔頂より水を主成分とする低沸成分を
留出させ、塔底よりＮ−メチル−２−ピロリドンを含む
高沸成分を抜き出し、製品のＮ−メチル−２−ピロリド
ンは側流から回収すること 第２蒸留塔の塔頂圧力は第１蒸留塔の塔頂圧力より
も低圧にすることを特徴とするＮ−メチル−２−ピロリ
ドンの精製方法を提供するものである。From the bottom of the first distillation column, N-methyl-2
-Pyrrolidone (a) and N-methyl-2-pyrrolidone A mixture of organic matter (b) having a smaller relative volatility is withdrawn and fed to the lower part of the second distillation column in a liquid phase state From the top of the second distillation column The low boiling point component containing water as the main component is distilled off, the high boiling point component containing N-methyl-2-pyrrolidone is withdrawn from the bottom of the column, and the product N-methyl-2-pyrrolidone is recovered from the side stream. The top pressure of the distillation column is lower than the top pressure of the first distillation column, which provides a method for purifying N-methyl-2-pyrrolidone.
【００１３】[0013]
【作用】蒸留塔２基を用いて反応生成物を連続蒸留する
場合、第１蒸留塔の留出物中に水を主成分とする軽沸成
分と原料として供給したＮＭＰの１〜３０重量％を含有
したままで第２蒸留塔の上部へ気相供給し、一方、塔底
から抜き出す高沸成分中の含水率を１重量％以下として
第２蒸留塔の下部へ液相供給し、第２蒸留塔の側流より
製品ＮＭＰを取得することで従来の慣習的な蒸留方法で
取得した製品と品質的に遜色なく、しかも第１塔及び第
２塔の還流比が大幅に削減されリボイラー・コンデンサ
ーの熱源の用役使用量が減少し熱経済的な連続蒸留が可
能になった。即ち、本発明ではＮＭＰ（ａ）と、水、及
びＮＭＰより比揮発度の小さい有機物（ｂ）の各々の比
揮発度差に基づく蒸留分離の容易さを利用したので熱経
済的な連続蒸留を行うことができた。When the reaction product is continuously distilled by using two distillation columns, 1 to 30% by weight of the light-boiling component containing water as the main component and NMP supplied as a raw material in the distillate of the first distillation column. Is supplied to the upper part of the second distillation column in the vapor phase, while the water content in the high boiling point component withdrawn from the bottom of the column is set to 1% by weight or less and the liquid phase is supplied to the lower part of the second distillation column. By obtaining the product NMP from the side stream of the distillation column, the quality is comparable to the product obtained by the conventional conventional distillation method, and the reflux ratio of the first and second columns is greatly reduced, and the reboiler condenser The amount of utility of the heat source was reduced, and thermo-economic continuous distillation became possible. That is, in the present invention, since the ease of distillation separation based on the relative volatility difference between NMP (a), water, and the organic matter (b) having a smaller relative volatility than NMP is utilized, thermo-economic continuous distillation is performed. I was able to do it.
【００１４】（発明の概要）反応水溶液 本発明の反応生成物のＮ−メチル−２−ピロリドン
（ａ）とＮ−メチル−２−ピロリドンより比揮発度の小
さい有機物（ｂ）を含む水溶液は、γ−ブチロラクトン
とモノメチルアミンとを反応させて得られたＮ−メチル
−２−ピロリドン反応生成物、２−ピロリドンとメタノ
ールとを反応させて得られたＮ−メチル−２−ピロリド
ン反応生成物であり、このものは、ＮＭＰよりも比揮発
度の小さい有機物（ｂ）を少量、好ましくは３重量％以
下含有し、水を５重量％以上、好ましくは１０〜５０重
量％含有し、ＮＭＰを５０重量％を越え、９５重量％未
満、好ましくは５５〜９０重量％含有する水溶液であ
る。(Summary of the Invention) Aqueous Reaction Solution An aqueous solution containing the reaction product of the present invention, N-methyl-2-pyrrolidone (a) and an organic matter (b) having a smaller specific volatility than N-methyl-2-pyrrolidone, an N-methyl-2-pyrrolidone reaction product obtained by reacting γ-butyrolactone and monomethylamine, and an N-methyl-2-pyrrolidone reaction product obtained by reacting 2-pyrrolidone and methanol. , Containing a small amount of organic matter (b) having a lower relative volatility than NMP, preferably 3% by weight or less, containing 5% by weight or more of water, preferably 10 to 50% by weight, and 50% by weight of NMP. % And less than 95% by weight, preferably 55 to 90% by weight.
【００１５】精製装置 本発明を実施する精製装置を図１を用いて説明する。図
中、１は第１蒸留塔、２は第２蒸留塔、３は反応生成物
の導管、４は還流管、５はガスライン、６は分縮器、
６′はリボイラー、７は供給ライン、８はガスライン、
９は凝縮器、１０は抜き出し管、１１は高沸点物の抜き
出しライン、１２は製品のＮＭＰの側流抜き出しライ
ン、１３はリボイラーである。 Refining Device A refining device for carrying out the present invention will be described with reference to FIG. In the figure, 1 is a first distillation column, 2 is a second distillation column, 3 is a reaction product conduit, 4 is a reflux pipe, 5 is a gas line, 6 is a partial condenser,
6'is a reboiler, 7 is a supply line, 8 is a gas line,
Reference numeral 9 is a condenser, 10 is an extraction pipe, 11 is a high-boiling-point extraction line, 12 is a side stream extraction line for NMP of the product, and 13 is a reboiler.
【００１６】精製方法 第１蒸留塔１にＮＭＰ（ａ）とＮＭＰよりも比揮発度の
小さな有機物（例えば２−ピロリドン）（ｂ）を含有し
た水溶液を反応器（図示しない）より液供給管３を経て
供給する。第１蒸留塔は理論段数１０〜２５段の充填
塔、あるいは棚段塔で塔内の圧力は常圧ないしは減圧下
に操作され、塔底温度は通常１５０℃ないしＮＭＰの沸
点＋１５℃、好ましくはＮＭＰの沸点＋５℃の範囲から
選択される。ＮＭＰはできるだけ、高温にさらさないよ
うにして蒸留するのが好ましい。塔頂より抜き出された
留出物は分縮器６で一部凝縮し還流ライン４を経由して
蒸留塔１へ戻される以外は、ガスライン５より気相のま
ま第２蒸留塔の上部に供給される。 Purification method An aqueous solution containing NMP (a) and an organic substance (eg, 2-pyrrolidone) (b) having a relative volatility smaller than that of NMP is supplied to the first distillation column 1 from a reactor (not shown) and a liquid supply pipe 3 Supply via. The first distillation column is a packed column having 10 to 25 theoretical plates or a plate column, and the pressure inside the column is operated under normal pressure or reduced pressure, and the column bottom temperature is usually 150 ° C. to the boiling point of NMP + 15 ° C., preferably It is selected from the range of the boiling point of NMP + 5 ° C. It is preferable to distill NMP so that it is not exposed to high temperature as much as possible. The distillate extracted from the top of the column is partially condensed in the dephlegmator 6 and returned to the distillation column 1 via the reflux line 4, except that it is in the gas phase from the gas line 5 in the upper part of the second distillation column. Is supplied to.
【００１７】液供給管３より供給したＮＭＰの１〜３０
％を第１蒸留塔の塔頂より留出させてガスライン５を経
由して第２蒸留塔へ供給することで、第１蒸留塔での還
流量の削減が可能になり、使用する熱源の用役使用量は
大幅に減少する。第２蒸留塔は理論段数２０〜３５段の
充填塔あるいは棚段塔で、塔内の圧力は第１蒸留塔より
も減圧で操作され、好ましくは５００ｍｍＨｇ以下、さ
らに好ましくは１０〜２００ｍｍＨｇ下で塔底温度は２
００℃以下、好ましくは１６０℃以下で減圧蒸留する。
塔頂からの留出ガスは通常、工業用水で冷却するため、
塔頂温度は３５〜７０℃の範囲が好ましい。1 to 30 of NMP supplied from the liquid supply pipe 3.
% By distilling from the top of the first distillation column and supplying it to the second distillation column via the gas line 5, it becomes possible to reduce the amount of reflux in the first distillation column, and to reduce the heat source used. The amount of utility usage is greatly reduced. The second distillation column is a packed column or a plate column with a theoretical plate number of 20 to 35, and the pressure in the column is operated at a pressure lower than that of the first distillation column, preferably 500 mmHg or less, more preferably 10 to 200 mmHg. Bottom temperature is 2
Vacuum distillation is carried out at a temperature of 00 ° C or lower, preferably 160 ° C or lower.
Since the distillate gas from the top of the tower is usually cooled with industrial water,
The tower top temperature is preferably in the range of 35 to 70 ° C.
【００１８】ガスライン５より供給された留出分に含ま
れる水の殆どがガスライン８を経由して凝縮器９で凝縮
した後、抜き出し管１０によって系外に放出される。一
方、製品ＮＭＰは第２蒸留塔の気相原料供給位置と液相
原料供給位置との中間の側流抜き出しライン１２より取
得される。尚、側流抜き出しライン１２は液相でも気相
抜き出しであってもかまわない。また気相原料供給位置
と側流からの製品抜き出し位置までの必要段数は、ガス
ライン５より供給されたＮＭＰを回収し、水を側流の製
品抜き出し位置では殆ど含ませないことのできる段数、
例えば理論段数１〜１０段、好ましくは２〜８段であ
る。Most of the water contained in the distillate supplied from the gas line 5 is condensed in the condenser 9 via the gas line 8 and then discharged to the outside of the system by the extraction pipe 10. On the other hand, the product NMP is obtained from the side stream withdrawal line 12 between the vapor phase raw material supply position and the liquid phase raw material supply position of the second distillation column. In addition, the side flow extraction line 12 may be liquid phase extraction or gas phase extraction. The required number of stages from the gas-phase raw material supply position to the sidestream product withdrawal position is such that the NMP supplied from the gas line 5 can be recovered and water can be hardly included at the sidestream product withdrawal position.
For example, the number of theoretical plates is 1 to 10, preferably 2 to 8.
【００１９】さらに、第１蒸留塔の塔底から第２蒸留塔
の下部に供給される液中には水は殆ど含有されていない
（１重量％以下）ため、ＮＭＰとＮＭＰより比揮発度の
小さい有機物の分離を第２蒸留塔の下段部分で行えばよ
く、ＮＭＰより比揮発度の小さい有機物は塔底の抜き出
し管１１より系外に抜き出す。尚、抜き出し管１１より
排出される高沸成分液には、通常は側流として抜き出す
ＮＭＰに対し１〜１５重量％のＮＭＰを高沸成分と一緒
に抜き出すように蒸留する。すなわち１〜１５重量％の
ＮＭＰを高沸成分と一緒に抜き出し、再蒸留してＮＭＰ
を回収すると製品に及ぼす影響が小さく、回収操作を安
定して行うことができるので有利である。Further, since the liquid supplied from the bottom of the first distillation column to the lower part of the second distillation column contains almost no water (1% by weight or less), NMP and NMP have a relative volatility higher than that of NMP. Small organic substances may be separated in the lower part of the second distillation column, and organic substances having a smaller specific volatility than NMP are withdrawn from the system through an extraction pipe 11 at the bottom of the column. The high-boiling component liquid discharged from the extraction pipe 11 is usually distilled so that 1 to 15% by weight of NMP is extracted as a side stream together with the high-boiling component. That is, 1 to 15% by weight of NMP is extracted together with the high boiling point component and redistilled to obtain NMP.
It is advantageous to recover the product because it has a small effect on the product and the recovery operation can be performed stably.
【００２０】[0020]
【実施例】以下に実施例により本発明を更に具体的に説
明するが、本発明は以下の実施例に限定されるものでは
ない。 実施例１ 反応容器内にγ−ブチロラクトン、モノメチルアミン及
び水を仕込み、Ｎ−メチル−２−ピロリドンの製造を行
った。製造条件として、モノメチルアミン／γ−ブチロ
ラクトンのモル比１．０８とし、水／γ−ブチロラクト
ンのモル比４．０とし、反応温度２５５℃、滞留時間３
時間として反応させた。The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to the following examples. Example 1 N-methyl-2-pyrrolidone was produced by charging γ-butyrolactone, monomethylamine and water into a reaction vessel. As production conditions, the molar ratio of monomethylamine / γ-butyrolactone was 1.08, the molar ratio of water / γ-butyrolactone was 4.0, the reaction temperature was 255 ° C., and the residence time was 3
It was made to react as time.
【００２１】得た反応生成物は、ＮＭＰ８３．５重量
％、２−ピロリドン１．２重量％および水１５．３重量
％を含有するものであった。この反応生成物を図１に示
す装置を用いてＮＭＰを精製した。第１蒸留塔は理論段
数２０段で、この上から１４段目の位置に反応生成物を
導管３より２３８．１Ｋｇ／Ｈｒの割合で供給した。第
１蒸留塔の塔頂圧力は５１０ｍｍＨｇとし、塔頂からの
留出物のうち５６．４Ｋｇ／Ｈｒ（水６４．７重量％、
ＮＭＰ３５．３重量％）をガスライン５を経由して気相
状態のまま第２蒸留塔（理論段数３０段）の５段に供給
し、残りは分縮器６にて凝縮後、還流ライン４より第１
蒸留塔へ戻した。また第１蒸留塔の塔底よりライン７に
て缶出物１８１．８Ｋｇ／Ｈｒ（ＮＭＰ９８．４重量
％、２−ピロリドン１．６重量％）を抜き出し、第２蒸
留塔の２２段に液相のまま供給した。The reaction product obtained contained 83.5% by weight of NMP, 1.2% by weight of 2-pyrrolidone and 15.3% by weight of water. NMP of this reaction product was purified using the apparatus shown in FIG. The first distillation column has 20 theoretical plates, and the reaction product was supplied to the position of the 14th plate from the top through the conduit 3 at a rate of 238.1 Kg / Hr. The top pressure of the first distillation column was 510 mmHg, and 56.4 Kg / Hr (64.7% by weight of water, of the distillate from the top of the column was
NMP (35.3 wt%) is supplied to the 5th stage of the second distillation column (30 theoretical stages) via the gas line 5 in the gas phase state, and the rest is condensed in the partial condenser 6 and then the reflux line 4 More first
Returned to the distillation column. Further, the bottom product 181.8 kg / Hr (NMP 98.4% by weight, 2-pyrrolidone 1.6% by weight) was extracted from the bottom of the first distillation column through a line 7, and the liquid phase was drawn in 22 stages of the second distillation column. It was supplied as is.
【００２２】第１蒸留塔のリボイラー６′での使用蒸気
量はエネルギー換算すると３１，３００Ｋｃａｌ／Ｈｒ
であり、分縮器６で要した除熱量は３，７００Ｋｃａｌ
／Ｈｒであった。第２蒸留塔は理論段数３０段を有し、
塔頂の圧力は１００ｍｍＨｇとした。第２蒸留塔の塔頂
よりの留出物３６．５Ｋｇ／Ｈｒ（水９９．７重量％、
ＮＭＰ０．３重量％）は凝縮９で凝縮後、系外１０に放
出した。The amount of steam used in the reboiler 6'of the first distillation column is 31,300 Kcal / Hr in terms of energy.
And the heat removal amount required by the demultiplexer 6 is 3,700 Kcal
Was / Hr. The second distillation column has 30 theoretical plates,
The pressure at the top of the column was 100 mmHg. Distillate from the top of the second distillation column 36.5 kg / Hr (water 99.7% by weight,
NMP (0.3 wt%) was condensed in the condensate 9 and then discharged outside the system 10.
【００２３】第２蒸留塔の塔底からはライン１１にて２
−ピロリドン１８．９重量％を含有する高沸物１４．８
Ｋｇ／Ｈｒを抜き出した。製品のＮＭＰは８段目の液相
より側流抜き出しで取得した。製品中のＮＭＰ純度は９
９．９５重量％以上あり、着色度はＡＰＨＡ１０であっ
た。第２蒸留塔のリボイラー１３の使用蒸気量は３６，
３００Ｋｃａｌ／Ｈｒであり、凝縮器９での除熱量は６
７，５００Ｋｃａｌ／Ｈｒであった。尚、ＡＰＨＡはＡ
ＳＴＭ Ｄ−１２０９に準じて測定した。Line 2 from the bottom of the second distillation column is 2
A high-boiling substance 14.8 containing 18.9% by weight of pyrrolidone
Kg / Hr was extracted. The NMP of the product was obtained by side-drawing from the liquid phase in the eighth stage. NMP purity in the product is 9
The content was 9.95% by weight or more, and the coloring degree was APHA10. The amount of steam used in the reboiler 13 of the second distillation column is 36,
It is 300 Kcal / Hr, and the heat removal amount in the condenser 9 is 6
It was 7,500 Kcal / Hr. APHA is A
It measured according to STM D-1209.
【００２４】比較例 実施例と同じ二基の蒸留塔を用いて図２に示す装置を用
い、従来の連続蒸留方式にてＮＭＰを精製した。第１蒸
留塔（理論段数２０段）に導管３より実施例の反応生成
物２３８．２Ｋｇ／Ｈｒ（水１５．３重量％、ＮＭＰ８
３．５重量％、２−ピロリドン１．２重量％）とライン
１０より第２蒸留塔（理論段数３０段）の塔頂からの留
出液１４．９Ｋｇ／Ｈｒ（水０．６重量％、ＮＭＰ９
９．４重量％）を供給した。第１蒸留塔の塔頂からの留
出液中のＮＭＰ濃度が０．１重量％以下になるように還
流を行い、３６．４Ｋｇ／Ｈｒの留出液をライン５より
系外に放出した。第１蒸留塔の塔底よりライン７にて缶
出液２１６．７Ｋｇ／Ｈｒ（ＮＭＰ９８．６重量％、２
−ピロリドン１．３重量％、水０．１重量％）を第２蒸
留塔に供給した。第１蒸留塔のリボイラー６′の使用蒸
気量をエネルギー換算すると４３，６００Ｋｃａｌ／Ｈ
ｒであり、分縮器６で要した除熱量は３７，２００Ｋｃ
ａｌ／Ｈｒであった。Comparative Example Using the same two distillation columns as in the example and using the apparatus shown in FIG. 2, NMP was purified by the conventional continuous distillation system. 238.2 Kg / Hr (15.3% by weight of water, NMP8) of the reaction product of the example from conduit 3 to the first distillation column (20 theoretical plates)
3.5 wt%, 2-pyrrolidone 1.2 wt%) and a distillate from the top of the second distillation column (30 theoretical plates) through line 10 14.9 kg / Hr (water 0.6 wt%, NMP9
9.4% by weight). Reflux was carried out so that the NMP concentration in the distillate from the top of the first distillation column was 0.1% by weight or less, and a distillate of 36.4 Kg / Hr was discharged from the system through line 5. From the bottom of the first distillation column, a bottom liquid 216.7 Kg / Hr (NMP 98.6% by weight, 2
-1.3% by weight of pyrrolidone, 0.1% by weight of water) was fed to the second distillation column. When the amount of steam used in the reboiler 6'of the first distillation column is converted into energy, it is 43,600 Kcal / H.
r, and the heat removal amount required by the demultiplexer 6 is 37,200 Kc
It was al / Hr.
【００２５】第２蒸留塔の塔底からは２−ピロリドン１
９．３重量％を含有する高沸物１５．０Ｋｇ／Ｈｒを抜
き出した。製品のＮＭＰは第２蒸留塔の４段目の液相よ
りライン１２にて側流抜き出しで取得した。製品中のＮ
ＭＰ純度は９９．９５重量％以上あり、着色度はＡＰＨ
Ａ１０であった。第２蒸留塔のリボイラー１３の使用蒸
気量４２，５００Ｋｃａｌ／Ｈｒであり、凝縮器９での
除熱量は４２，３００Ｋｃａｌ／Ｈｒであった。2-pyrrolidone 1 is discharged from the bottom of the second distillation column.
15.0 Kg / Hr of high boiler containing 9.3% by weight was withdrawn. The NMP of the product was obtained by side-flow extraction in line 12 from the liquid phase at the fourth stage of the second distillation column. N in the product
MP purity is over 99.95% by weight, coloring degree is APH
It was A10. The amount of steam used in the reboiler 13 of the second distillation column was 42,500 Kcal / Hr, and the heat removal amount in the condenser 9 was 42,300 Kcal / Hr.
【００２６】[0026]
【発明の効果】１００℃におけるＮＭＰの蒸気圧は２４
ｍｍＨｇ、２−ピロリドンの蒸気圧は３ｍｍＨｇ、水の
蒸気圧は７６０ｍｍＨｇであり、２−ピロリドンのＮＭ
Ｐに対する比揮発度α1 は０．１２５、水のＮＭＰに対
する比揮発度α2 は３１．６６７となる。従来の方法で
は水及び高沸物の分離除去時のＮＭＰ同伴損失を出来る
限り少なく抑制するために、比揮発度αが水のようにか
なり大きな物質であっても、大量の還流をかけて塔頂で
のＮＭＰが微量になるように蒸留操作を行っていた。The NMP vapor pressure at 100 ° C. is 24
mmHg and 2-pyrrolidone have a vapor pressure of 3 mmHg and water have a vapor pressure of 760 mmHg.
The relative volatility α 1 for P is 0.125, and the relative volatility α 2 for NMP of water is 31.667. In the conventional method, in order to suppress the entrainment loss of NMP during separation and removal of water and high-boiling substances as much as possible, even if a substance with a relatively high specific volatility α such as water is used, a large amount of reflux is applied to the tower. The distillation operation was performed so that the amount of NMP at the top was very small.
【００２７】本発明においては、ＮＭＰに対する２−ピ
ロリドンの比揮発度α1 およびＮＭＰに対する水の比揮
発度α2 が１からかなり離れていることが蒸留によって
分離しやすいことに着目してなされたので、第１蒸留塔
で少量の還流によって粗分離した後、第２蒸留塔で容易
にＮＭＰを分離することが可能になる。しかも、第１蒸
留塔の塔頂から留出する水を凝縮することなく第２蒸留
塔に供給することで大幅なエネルギーの削減が達成され
た。In the present invention, the fact that the relative volatility α 1 of 2-pyrrolidone to NMP and the relative volatility α 2 of water to NMP are considerably different from 1 is easily separated by distillation. Therefore, it becomes possible to easily separate NMP in the second distillation column after roughly separating it by a small amount of reflux in the first distillation column. Moreover, a significant reduction in energy was achieved by supplying the water distilled from the top of the first distillation column to the second distillation column without condensing it.
【００２８】また、ライン５からの留出物を従来の慣習
的な蒸留塔からの軽沸物のように系外へ抜き出す場合に
は、ＮＭＰのロスを最小限に抑制するため、ＮＭＰの濃
度が極力小さくなるように還流をかける必要があった
が、本発明では第１蒸留塔の塔頂のＮＭＰの量に係わり
なく、塔底のライン７から抜き出されるＮＭＰ液中の含
水率を１重量％以下に保持すれば、第２蒸留塔で連続的
にＮＭＰを回収することが可能である。When the distillate from the line 5 is withdrawn from the system like a light boiling product from a conventional conventional distillation column, the NMP concentration is reduced to minimize the NMP loss. However, in the present invention, the water content in the NMP liquid extracted from the line 7 at the bottom of the column is 1 regardless of the amount of NMP at the top of the first distillation column. If it is kept at less than or equal to wt%, NMP can be continuously recovered in the second distillation column.
【図１】本発明のＮＭＰ生成物の精製方法を実施する装
置の平面図である。FIG. 1 is a plan view of an apparatus for carrying out an NMP product purification method of the present invention.
【図２】従来のＮＭＰ生成物の精製方法を実施する装置
の平面図である。FIG. 2 is a plan view of an apparatus for carrying out a conventional method for purifying an NMP product.
１ 第１蒸留塔 ２ 第２蒸留塔 ３ ＮＭＰ水溶液の導管 １２ 高純度のＮＭＰの抜き出し管 1 First distillation column 2 Second distillation column 3 NMP aqueous solution conduit 12 High-purity NMP extraction pipe
Claims (3)
−メチル−２−ピロリドンより比揮発度の小さい有機物
（ｂ）を含む水溶液を蒸留して水と該有機物をほとんど
含まないＮ−メチル−２−ピロリドンを製造する方法に
おいて、 該水溶液を第１蒸留塔に供給して、塔頂から水とＮ
−メチル−２−ピロリドンを留出し、その一部を分縮さ
せて第１蒸留塔へ還流として戻し、残りを凝縮すること
なく第２蒸留塔の上部に気相状態で供給すること、 第１蒸留塔の塔底からＮ−メチル−２−ピロリドン
（ａ）とＮ−メチル−２−ピロリドンより比揮発度の小
さな有機物（ｂ）の混合物を抜き出し、第２蒸留塔の下
部に液相状態で供給すること 第２蒸留塔の塔頂より水を主成分とする低沸成分を
留出させ、塔底よりＮ−メチル−２−ピロリドンを含む
高沸成分を抜き出し、製品のＮ−メチル−２−ピロリド
ンは側流から回収すること 第２蒸留塔の塔頂圧力は第１蒸留塔の塔頂圧力より
も低圧にすることを特徴とするＮ−メチル−２−ピロリ
ドンの精製方法。1. N-methyl-2-pyrrolidone (a) and N
In the method for producing N-methyl-2-pyrrolidone containing almost no water and the organic substance by distilling an aqueous solution containing the organic substance (b) having a smaller relative volatility than methyl-2-pyrrolidone, the aqueous solution is first distilled. Supply to the tower, water and N from the top of the tower
-Methyl-2-pyrrolidone is distilled off, a part of it is condensed and returned to the first distillation column as reflux, and the rest is supplied to the upper part of the second distillation column in the vapor phase without condensing. A mixture of N-methyl-2-pyrrolidone (a) and an organic substance (b) having a smaller specific volatility than N-methyl-2-pyrrolidone was extracted from the bottom of the distillation column, and in a liquid phase state at the bottom of the second distillation column. Supplying The low boiling point component containing water as the main component is distilled from the top of the second distillation column, the high boiling point component containing N-methyl-2-pyrrolidone is extracted from the bottom of the column, and N-methyl-2 of the product is supplied. -Pyrrolidone is recovered from a side stream A method for purifying N-methyl-2-pyrrolidone, wherein the top pressure of the second distillation column is lower than the top pressure of the first distillation column.
チル−２−ピロリドンの量は原料として供給されたＮ−
メチル−２−ピロリドンの１〜３０重量％であり、かつ
塔底から抜き出されて第２蒸留塔に供給されるＮ−メチ
ル−２−ピロリドン溶液中の含水率は１重量％以下であ
ることを特徴とする請求項１記載の精製方法。2. The amount of N-methyl-2-pyrrolidone distilled from the top of the first distillation column is the amount of N- supplied as a raw material.
It is 1 to 30% by weight of methyl-2-pyrrolidone, and the water content in the N-methyl-2-pyrrolidone solution extracted from the bottom of the column and supplied to the second distillation column is 1% by weight or less. The purification method according to claim 1, wherein
ロリドンを側流として回収する位置は、気相原料供給位
置と液相原料供給位置との中間であることを特徴とする
請求項１記載の精製方法。3. The position for collecting N-methyl-2-pyrrolidone of the product of the second distillation column as a sidestream is an intermediate position between the gas phase raw material supply position and the liquid phase raw material supply position. Item 1. The purification method according to Item 1.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP24543494A JP3486984B2 (en) | 1994-10-11 | 1994-10-11 | Method for purifying N-methyl-2-pyrrolidone |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP24543494A JP3486984B2 (en) | 1994-10-11 | 1994-10-11 | Method for purifying N-methyl-2-pyrrolidone |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH08109167A true JPH08109167A (en) | 1996-04-30 |
| JP3486984B2 JP3486984B2 (en) | 2004-01-13 |
Family
ID=17133607
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP24543494A Expired - Fee Related JP3486984B2 (en) | 1994-10-11 | 1994-10-11 | Method for purifying N-methyl-2-pyrrolidone |
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| Country | Link |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2001354647A (en) * | 2000-06-14 | 2001-12-25 | Mitsubishi Chemicals Corp | N-methyl-2-pyrrolidone composition and method for producing the same |
| WO2011030728A1 (en) * | 2009-09-14 | 2011-03-17 | 三菱化学エンジニアリング株式会社 | Nmp distilling apparatus |
| CN102399179A (en) * | 2010-09-17 | 2012-04-04 | 上海化学试剂研究所 | Production process for ultra-pure N-methylpyrrolidone |
| WO2012120666A1 (en) * | 2011-03-09 | 2012-09-13 | 三菱化学エンジニアリング株式会社 | Device for distilling nmp |
| CN102921306A (en) * | 2012-11-16 | 2013-02-13 | 北京碧水源膜科技有限公司 | Recovery method of separating film gelling bath solution and separating film prepared by recovered material |
| WO2016017491A1 (en) * | 2014-07-29 | 2016-02-04 | オルガノ株式会社 | System and method for organic solvent purification |
| WO2018179239A1 (en) * | 2017-03-30 | 2018-10-04 | 三菱ケミカルエンジニアリング株式会社 | Nmp distilling apparatus |
| CN111269163A (en) * | 2020-03-19 | 2020-06-12 | 江苏盈天化学有限公司 | Method for removing gamma butyrolactone in N-methyl pyrrolidone |
| JP2021523898A (en) * | 2018-09-28 | 2021-09-09 | エルジー・ケム・リミテッド | Recovery method and equipment for amide compounds |
| CN114432728A (en) * | 2022-04-11 | 2022-05-06 | 天津中福环保科技股份有限公司 | System and process for purifying NMP |
-
1994
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