JP2008266290A - Method for recovering cyclohexanone oxime - Google Patents

Method for recovering cyclohexanone oxime Download PDF

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JP2008266290A
JP2008266290A JP2007327759A JP2007327759A JP2008266290A JP 2008266290 A JP2008266290 A JP 2008266290A JP 2007327759 A JP2007327759 A JP 2007327759A JP 2007327759 A JP2007327759 A JP 2007327759A JP 2008266290 A JP2008266290 A JP 2008266290A
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cyclohexanone oxime
gas
residue
recovered
recovering
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JP5236273B2 (en
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Masashi Yokota
雅志 横田
Kanji Kuwabara
寛治 桑原
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Sumitomo Chemical Co Ltd
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Sumitomo Chemical Co Ltd
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Priority to TW097110686A priority patent/TWI346099B/en
Priority to DE602008002353T priority patent/DE602008002353D1/en
Priority to EP08153394A priority patent/EP1985609B1/en
Priority to US12/078,278 priority patent/US20080242891A1/en
Priority to SG200802529-8A priority patent/SG146598A1/en
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    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C249/00—Preparation of compounds containing nitrogen atoms doubly-bound to a carbon skeleton
    • C07C249/04—Preparation of compounds containing nitrogen atoms doubly-bound to a carbon skeleton of oximes
    • C07C249/14—Separation; Purification; Stabilisation; Use of additives
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C249/00—Preparation of compounds containing nitrogen atoms doubly-bound to a carbon skeleton
    • C07C249/04—Preparation of compounds containing nitrogen atoms doubly-bound to a carbon skeleton of oximes

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Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for recovering cyclohexanone oxime, wherein cyclohexanone oxime can be recovered with a high recovery rate from the mixture of cyclohexanone oxime and the tar of cyclohexanone oxime origin formed as a residue after the evaporation of liquid cyclohexanone oxime. <P>SOLUTION: A liquid cyclohexanone oxime A is vaporized by heating to form a cyclohexanone oxime gas A1, and the remaining residue C is distilled under pressure lower than that upon the vaporization by heating, and then cyclohexanone oxime A2 contained in the residue C is recovered. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

本発明は、液状シクロヘキサノンオキシムを加熱蒸発させた後の残渣から、該残渣に含まれるシクロヘキサノンオキシムを回収する方法に関する。   The present invention relates to a method for recovering cyclohexanone oxime contained in a residue from the residue after liquid cyclohexanone oxime is evaporated by heating.

ε−カプロラクタム（以下「ラクタム」と称することもある）は、主に繊維やエンジニアリングプラクチックスの製造に使用されるナイロン−６の合成に用いられるモノマーである。ラクタムの製造には、ガス状のシクロヘキサノンオキシムを出発原料として気相ベックマン転位反応を行う方法が知られている。   ε-Caprolactam (hereinafter sometimes referred to as “lactam”) is a monomer mainly used for the synthesis of nylon-6, which is used for the production of fibers and engineering plastics. For the production of lactam, a method of performing a gas phase Beckmann rearrangement reaction using gaseous cyclohexanone oxime as a starting material is known.

気相ベックマン転位反応においては、濡壁蒸発器を用いて液状のシクロヘキサノンオキシムを加熱、蒸発させて、ガス状のシクロヘキサノンオキシムを得る（特許文献１参照）。しかしながら、シクロヘキサノンオキシムは熱安定性が悪いため、加熱して蒸発させる工程において熱分解や熱縮合等を起こしてタールを副生し易い。かかるタールは、濡壁蒸発器の閉塞を招くため残渣として外部に排出する必要があるが、このとき、タールとともに液状シクロヘキサノンオキシムも一緒に排出されてしまい、ガス状シクロヘキサノンオキシムを高い収率で得ることができないという問題があった。   In the gas phase Beckmann rearrangement reaction, liquid cyclohexanone oxime is heated and evaporated using a wet wall evaporator to obtain gaseous cyclohexanone oxime (see Patent Document 1). However, since cyclohexanone oxime has poor thermal stability, tar is easily produced as a by-product by causing thermal decomposition, thermal condensation, or the like in the process of heating and evaporating. Such tar needs to be discharged to the outside as a residue because it causes clogging of the wet wall evaporator. At this time, liquid cyclohexanone oxime is also discharged together with tar, and gaseous cyclohexanone oxime is obtained in high yield. There was a problem that I could not.

特開２００２−２８４７５２号公報Japanese Patent Laid-Open No. 2002-284752

そこで、本発明は、シクロヘキサノンオキシムの熱安定性に配慮しながら、液状シクロヘキサノンオキシムを加熱蒸発させた後の残渣から簡便な方法で効率よくシクロヘキサノンオキシムを回収する方法を提供することを目的とする。   Therefore, an object of the present invention is to provide a method for efficiently recovering cyclohexanone oxime from a residue after heating and evaporating liquid cyclohexanone oxime with a simple method, while taking into consideration the thermal stability of cyclohexanone oxime.

本発明者は、上記課題を解決するべく鋭意研究した結果、シクロヘキサノンオキシムと副生タールとの沸点差が大きいことに着目し、液状シクロヘキサノンオキシムを加熱蒸発した後の残渣からシクロヘキサノンオキシムを回収するにあたり、前記残渣を別の蒸発器にて、シクロヘキサノンオキシムを加熱蒸発させる際の圧力よりも低い圧力（以下「低圧力」と称することがある。）の下で蒸留することによって、その熱安定性に配慮しつつ、簡便に、高回収率で、シクロヘキサノンオキシムをタール分と分離して回収できることを見出した。   As a result of earnest research to solve the above-mentioned problems, the present inventor has paid attention to the large difference in boiling point between cyclohexanone oxime and by-product tar, and in recovering cyclohexanone oxime from the residue after heating and evaporating liquid cyclohexanone oxime By distilling the residue in a separate evaporator under a pressure lower than the pressure at which cyclohexanone oxime is evaporated by heating (hereinafter sometimes referred to as “low pressure”), the thermal stability of the residue is reduced. The present inventors have found that cyclohexanone oxime can be separated and recovered from the tar content in a simple and high recovery rate while taking into consideration.

さらに、本発明者は、回収したシクロヘキサノンオキシムを再利用する際の簡便性に鑑み、前記低圧力の下での蒸留により留去させたシクロヘキサノンオキシムガスを液状として回収することを目指し、シクロヘキサノンオキシムガスを凝縮器で凝縮させることを試みた。しかし、シクロヘキサノンオキシムは融点が９０℃と高いため、９０℃未満の冷却用媒体を用いた場合、凝縮器内でシクロヘキサノンオキシムの結晶が析出しやすく、凝縮器内で閉塞を招く。さらに、この結晶析出を防止するべく凝縮器の冷却用媒体として９０℃以上の熱水を用いた場合には、シクロヘキサノンオキシムの蒸気圧が比較的高いため、未凝縮ガスが多くなり回収ロスが無視できなくなるうえ、排ガス配管での結晶析出は回避できず、やはり配管の閉塞を招くことになる。このように、いずれにしてもシクロヘキサノンオキシムの結晶化によって連続した安定操業が妨げられるという問題があった。なお、凝縮器の冷却用媒体として９０℃以上の熱水を用いた場合の未凝縮ガスを減少させるためには、蒸留を行う前記蒸発器の操作圧力を常圧以上とすることが考えられるが、蒸発器の操作温度を高くするとタール分の副生が助長されることになる。これらの問題をも解決するべく、本発明者は検討を重ねた結果、前記低圧力の下での蒸留により留去されたシクロヘキサノンオキシムガスを、シクロヘキサノンオキシムを溶解しうる溶剤に接触させてシクロヘキサノンオキシム溶液とすることにより、前記問題を回避しつつシクロヘキサノンオキシムを液状で回収することができることを見出した。
本発明は、これらの知見に基づき完成したものである。 Furthermore, the present inventor aims to recover the cyclohexanone oxime gas distilled off by distillation under the low pressure as a liquid in view of the convenience in reusing the recovered cyclohexanone oxime. I tried to condense it with a condenser. However, since the melting point of cyclohexanone oxime is as high as 90 ° C., when a cooling medium of less than 90 ° C. is used, crystals of cyclohexanone oxime are likely to precipitate in the condenser, which causes clogging in the condenser. Furthermore, when hot water of 90 ° C. or higher is used as a cooling medium for the condenser to prevent this crystal precipitation, the vapor pressure of cyclohexanone oxime is relatively high, so the amount of uncondensed gas increases and the recovery loss is ignored. In addition, it is impossible to avoid crystal precipitation in the exhaust gas pipe, which also causes the pipe to be blocked. Thus, in any case, there has been a problem that continuous stable operation is hindered by crystallization of cyclohexanone oxime. In order to reduce uncondensed gas when hot water of 90 ° C. or higher is used as the condenser cooling medium, it is conceivable that the operating pressure of the evaporator for performing distillation is set to normal pressure or higher. By raising the operating temperature of the evaporator, the by-product of tar is promoted. In order to solve these problems as well, the present inventor has made studies and as a result, the cyclohexanone oxime gas distilled by distillation under the low pressure is brought into contact with a solvent capable of dissolving cyclohexanone oxime to obtain cyclohexanone oxime. It has been found that cyclohexanone oxime can be recovered in liquid form while avoiding the above problems by using a solution.
The present invention has been completed based on these findings.

すなわち、本発明は以下の構成からなる。
（１）液状シクロヘキサノンオキシムを加熱蒸発させてシクロヘキサノンオキシムガス(Ａ１)を得た後の残渣を、加熱蒸発させる際の圧力よりも低い圧力の下に蒸留し、前記残渣に含まれるシクロヘキサノンオキシムを回収することを特徴とするシクロヘキサノンオキシムの回収方法。
（２）前記蒸留は、１．４〜１０ｋＰａ（絶対圧力）の下で行う、前記（１）記載のシクロヘキサノンオキシムの回収方法。
（３）前記残渣を蒸留することにより留去されたシクロヘキサノンオキシムガス(Ａ２)を、シクロヘキサノンオキシムを溶解しうる溶剤に接触させてシクロヘキサノンオキシム溶液とし、回収する、前記（１）または（２）記載のシクロヘキサノンオキシムの回収方法。
（４）前記残渣を蒸留することにより留去されたシクロヘキサノンオキシムガス(Ａ２)を、９０℃以上の冷却用媒体を用いた凝縮器で凝縮してシクロヘキサノンオキシム凝縮液（Ａ３）を得、同時に得られた未凝縮のシクロヘキサノンオキシムガス（Ａ４）を、シクロヘキサノンオキシムを溶解しうる溶剤に接触させてシクロヘキサノンオキシム溶液とし、回収する、前記（１）または（２）記載のシクロヘキサノンオキシムの回収方法。
（５）前記シクロヘキサノンオキシムガス(Ａ２)またはシクロヘキサノンオキシムガス（Ａ４）を、冷却体の表面で前記溶剤と接触させる、前記（３）または（４）記載のシクロヘキサノンオキシムの回収方法。 That is, the present invention has the following configuration.
(1) Liquid cyclohexanone oxime is heated and evaporated to obtain a cyclohexanone oxime gas (A1), and the residue is distilled under a pressure lower than the pressure at the time of heat evaporation to recover cyclohexanone oxime contained in the residue. And a method for recovering cyclohexanone oxime.
(2) The method for recovering cyclohexanone oxime according to (1), wherein the distillation is performed under 1.4 to 10 kPa (absolute pressure).
(3) The above described (1) or (2), wherein the cyclohexanone oxime gas (A2) distilled off by distillation of the residue is brought into contact with a solvent capable of dissolving cyclohexanone oxime to obtain a cyclohexanone oxime solution and recovered. Method for recovering cyclohexanone oxime.
(4) The cyclohexanone oxime gas (A2) distilled off by distillation of the residue is condensed in a condenser using a cooling medium of 90 ° C. or higher to obtain a cyclohexanone oxime condensate (A3), which is obtained at the same time. The method for recovering cyclohexanone oxime according to (1) or (2) above, wherein the non-condensed cyclohexanone oxime gas (A4) is brought into contact with a solvent capable of dissolving cyclohexanone oxime to form a cyclohexanone oxime solution and recovered.
(5) The method for recovering cyclohexanone oxime according to (3) or (4), wherein the cyclohexanone oxime gas (A2) or cyclohexanone oxime gas (A4) is brought into contact with the solvent on the surface of a cooling body.

本発明によれば、液状シクロヘキサノンオキシムを気化させた後に残渣として得られるシクロヘキサノンオキシムとシクロヘキサノンオキシム由来のタール分との混合物から、簡便に、高い回収率でシクロヘキサノンオキシムを得ることができる、という効果が得られる。しかも、本発明によれば、前記残渣は低圧力の下で蒸留するので、比較的低温でシクロヘキサノンオキシムを留去させることができ、得られるシクロヘキサノンオキシムの熱劣化を抑制することもできる。加えて、前記低圧力の下での蒸留により留去させたシクロヘキサノンオキシムを、シクロヘキサノンオキシムを溶解しうる溶剤に接触させてシクロヘキサノンオキシム溶液とすることにより、凝縮器や凝縮器に連結する配管等におけるシクロヘキサノンオキシムの固結（結晶析出）を抑制しつつ、シクロヘキサノンオキシムを液状で回収することが可能になり、回収したシクロヘキサノンオキシムを再利用する際の簡便性を向上させることができる。   According to the present invention, from the mixture of cyclohexanone oxime obtained as a residue after vaporizing liquid cyclohexanone oxime and the tar content derived from cyclohexanone oxime, there is an effect that cyclohexanone oxime can be easily obtained at a high recovery rate. can get. In addition, according to the present invention, since the residue is distilled under a low pressure, cyclohexanone oxime can be distilled off at a relatively low temperature, and thermal deterioration of the resulting cyclohexanone oxime can also be suppressed. In addition, the cyclohexanone oxime distilled off by distillation under the low pressure is brought into contact with a solvent capable of dissolving cyclohexanone oxime to form a cyclohexanone oxime solution, whereby a condenser or a pipe connected to the condenser is used. Cyclohexanone oxime can be recovered in a liquid state while suppressing the consolidation (crystal precipitation) of cyclohexanone oxime, and the convenience in reusing the recovered cyclohexanone oxime can be improved.

また、本発明によって得られたシクロヘキサノンオキシムを気相ベックマン転位反応によるラクタムの製造用原料として再使用することにより、原料であるシクロヘキサノンオキシムの利用効率が高い生産性に優れたラクタムの製造工程を確立することができる、という効果も得られる。   In addition, by reusing the cyclohexanone oxime obtained by the present invention as a raw material for the production of lactam by the gas phase Beckmann rearrangement reaction, a process for producing a lactam with high utilization efficiency of the raw material cyclohexanone oxime and high productivity is established. The effect that it can do is also acquired.

本発明のシクロヘキサノンオキシムの回収方法は、例えば気相ベックマン転位反応によるε−カプロラクタムの製造において原料とするシクロヘキサノンオキシムガス(Ａ１)を得るために、液状シクロヘキサノンオキシムを加熱蒸発させた後の残渣から、シクロヘキサノンオキシムを回収する方法である。詳しくは、前記残渣はシクロヘキサノンオキシムと該オキシムの加熱分解物などからなるタール分とを含む混合物であり、本発明は、この混合物からシクロヘキサノンオキシムのみを留去させて回収する方法である。
前記残渣を得る際の液状シクロヘキサノンオキシムの加熱蒸発は、通常は、減圧しない状態、すなわち常圧ないしは加圧の状態で行うものであり、具体的には、通常、１３０〜１７０℃で、１０１〜１４０ｋＰａ（絶対圧力）で行われる。 In order to obtain cyclohexanone oxime gas (A1) as a raw material in the production of ε-caprolactam, for example, by vapor phase Beckmann rearrangement reaction, the cyclohexanone oxime recovery method of the present invention is obtained from the residue after heating and evaporating liquid cyclohexanone oxime, This is a method for recovering cyclohexanone oxime. Specifically, the residue is a mixture containing cyclohexanone oxime and a tar component composed of a thermal decomposition product of the oxime, and the present invention is a method for recovering by distilling off only cyclohexanone oxime from the mixture.
The liquid cyclohexanone oxime is heated and evaporated when the residue is obtained, usually in a state where the pressure is not reduced, that is, in a normal pressure or a pressurized state. It is performed at 140 kPa (absolute pressure).

本発明においては、前記残渣を低圧力の下にて蒸留する。低圧力の下で蒸留することにより、比較的低い温度でシクロヘキサノンオキシムを留去させることができるので、得られるシクロヘキサノンオキシムの熱劣化を抑制することができ、ひいては高い回収率を達成することができる。例えば、前記蒸留は、１．４〜１０ｋＰａ（絶対圧力）の減圧下で行うことが好ましく、より好ましくは１．４〜８ｋＰａ（絶対圧力）の減圧下で行うのがよい。蒸留時の圧力が１．４ｋＰａ（絶対圧力）未満であると、シクロヘキサノンオキシムが固結する傾向があり、一方、１０ｋＰａ（絶対圧力）を超えると、シクロヘキサノンオキシムの熱劣化が進みやすくなる傾向がある。   In the present invention, the residue is distilled under a low pressure. By distilling under a low pressure, cyclohexanone oxime can be distilled off at a relatively low temperature, so that thermal deterioration of the resulting cyclohexanone oxime can be suppressed, and thus a high recovery rate can be achieved. . For example, the distillation is preferably performed under reduced pressure of 1.4 to 10 kPa (absolute pressure), and more preferably performed under reduced pressure of 1.4 to 8 kPa (absolute pressure). If the pressure during distillation is less than 1.4 kPa (absolute pressure), cyclohexanone oxime tends to consolidate, whereas if it exceeds 10 kPa (absolute pressure), thermal degradation of cyclohexanone oxime tends to proceed easily. .

前記蒸留の際の温度（蒸留温度）は、９０〜１３５℃とするのが好ましく、より好ましくは９０〜１２５℃とするのがよい。蒸留温度が９０℃未満になると、シクロヘキサノンオキシムが固結する傾向があり、一方、１３５℃を超えると、シクロヘキサノンオキシムの熱劣化が進みやすくなる傾向がある。   The temperature during distillation (distillation temperature) is preferably 90 to 135 ° C, and more preferably 90 to 125 ° C. When the distillation temperature is less than 90 ° C., cyclohexanone oxime tends to solidify, while when it exceeds 135 ° C., thermal degradation of cyclohexanone oxime tends to proceed easily.

このようにして、前記残渣を低圧力の下にて蒸留することにより留去されたシクロヘキサノンオキシムガス(Ａ２)は、（Ｉ）シクロヘキサノンオキシムを溶解しうる溶剤に接触させてシクロヘキサノンオキシム溶液とし、回収するか、（ＩＩ）９０℃以上の冷却用媒体を用いた凝縮器で凝縮してシクロヘキサノンオキシム凝縮液（Ａ３）を得、同時に得られた未凝縮のシクロヘキサノンオキシムガス（Ａ４）を、シクロヘキサノンオキシムを溶解しうる溶剤に接触させてシクロヘキサノンオキシム溶液とし、回収することが好ましい。これにより、凝縮器や凝縮器に連結する配管等におけるシクロヘキサノンオキシムの固結（結晶析出）を抑制しつつ、回収したシクロヘキサノンオキシムを再利用する際の簡便性を向上させることができる。   Thus, the cyclohexanone oxime gas (A2) distilled off by distilling the residue under a low pressure is brought into contact with a solvent capable of dissolving (I) cyclohexanone oxime to form a cyclohexanone oxime solution and recovered. Or (II) to obtain a cyclohexanone oxime condensate (A3) by condensing in a condenser using a cooling medium of 90 ° C. or higher, and simultaneously obtaining the uncondensed cyclohexanone oxime gas (A4) from cyclohexanone oxime. The cyclohexanone oxime solution is preferably brought into contact with a soluble solvent and recovered. Thereby, the simplicity at the time of reusing the recovered cyclohexanone oxime can be improved while suppressing the consolidation (crystal precipitation) of cyclohexanone oxime in the condenser and the pipe connected to the condenser.

前記溶剤としては、シクロヘキサノンオキシムを溶解しうるものが用いられ、具体的には、例えば、メタノール、エタノール、ｎ−プロパノール、イソプロパノール、ｔ−ブタノール等のアルコール類や、トルエン、シクロヘキサノンなどが好ましく用いられる。   As the solvent, those capable of dissolving cyclohexanone oxime are used, and specifically, for example, alcohols such as methanol, ethanol, n-propanol, isopropanol, t-butanol, toluene, cyclohexanone and the like are preferably used. .

前記シクロヘキサノンオキシムガス(Ａ２) またはシクロヘキサノンオキシムガス（Ａ４）を前記溶剤に接触させる際には、（ｉ）シクロヘキサノンオキシムガス(Ａ２) または（Ａ４）を蒸気のまま直接溶剤と接触させる直接接触式の凝縮器、(ｉｉ）シクロヘキサノンオキシムガス(Ａ２) または（Ａ４）を凝縮させて液状とし、これに溶剤を接触させる間接接触式の凝縮器、のいずれかが用いられる。具体的には、前記（ｉ）の凝縮器は、前記低圧力の下での蒸留の操作圧力において沸点未満である温度に冷却した前記溶剤をスプレーノズル等を用いて前記シクロヘキサノンオキシムガス(Ａ２) または（Ａ４）の蒸気中に噴霧するものであればよく、例えば、スプレー塔、充填塔など一般的なガス吸収装置を利用することができる。他方、前記（ｉｉ）の凝縮器は、前記シクロヘキサノンオキシムガス(Ａ２) または（Ａ４）を冷却体（熱交換器など）の表面で前記溶剤と接触させる（つまり、シクロヘキサノンオキシムガス（Ａ２）または（Ａ４）の蒸気が冷却体の表面で冷却されて凝縮したところへ前記溶剤を噴霧する）ものであればよく、例えば、多管式熱交換器など一般的な形式の熱交換器を利用することができる。   When the cyclohexanone oxime gas (A2) or cyclohexanone oxime gas (A4) is brought into contact with the solvent, (i) the cyclohexanone oxime gas (A2) or (A4) is brought into direct contact with the solvent as a vapor. Either a condenser, or (ii) an indirect contact condenser in which cyclohexanone oxime gas (A2) or (A4) is condensed to form a liquid and a solvent is brought into contact therewith is used. Specifically, in the condenser (i), the cyclohexanone oxime gas (A2) is obtained by using a spray nozzle or the like to cool the solvent cooled to a temperature lower than the boiling point at the operation pressure of distillation under the low pressure. Or what is necessary is just to spray in the vapor | steam of (A4), for example, common gas absorption apparatuses, such as a spray tower and a packed tower, can be utilized. On the other hand, the condenser (ii) brings the cyclohexanone oxime gas (A2) or (A4) into contact with the solvent on the surface of a cooling body (such as a heat exchanger) (that is, cyclohexanone oxime gas (A2) or ( A4) may be used as long as the solvent is sprayed on the surface where the vapor is cooled and condensed on the surface of the cooling body. For example, a general type heat exchanger such as a multi-tube heat exchanger is used. Can do.

本発明によって回収されたシクロヘキサノンオキシムを気相ベックマン転位反応に再使用することにより、原料であるシクロヘキサノンオキシムの利用効率が高い生産性に優れたラクタムの製造工程を確立することができる。   By reusing the cyclohexanone oxime recovered by the present invention in the gas phase Beckmann rearrangement reaction, a lactam production process with high utilization efficiency of the raw material cyclohexanone oxime and excellent productivity can be established.

以下、実施例によって本発明を詳細に説明するが、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）
図１に示すフローチャートに準じて、シクロヘキサノンオキシムの回収を行った。
まず、液状シクロヘキサノンオキシムＡを、スチーム（図示せず）により加熱された蒸発器１００に供給し、１１６ｋＰａ（絶対圧力）の下で加熱蒸発させた。これによって、シクロヘキサノンオキシムガスＡ１を生じさせると同時に、残渣Ｃとして、シクロヘキサノンオキシムとシクロヘキサノンオキシム由来のタール分との混合物を１０重量部／時で得た。この残渣Ｃは、次いでスチーム（図示せず）により加熱された減圧蒸留器１０１に導入し、真空ポンプ（図示せず）により該蒸留器１０１内部を４．９ｋＰａ（絶対圧力）の減圧にして、１２０℃で蒸留を行った。そして、９重量部／時でシクロヘキサノンオキシムＡ２を留去させるとともに、蒸留残渣であるタール分Ｄを減圧蒸留器１０１底部から１重量部／時で排出した。 EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited to a following example.
Example 1
According to the flowchart shown in FIG. 1, cyclohexanone oxime was recovered.
First, liquid cyclohexanone oxime A was supplied to the evaporator 100 heated by steam (not shown), and was evaporated by heating under 116 kPa (absolute pressure). As a result, cyclohexanone oxime gas A1 was produced, and at the same time, as residue C, a mixture of cyclohexanone oxime and tar content derived from cyclohexanone oxime was obtained at 10 parts by weight / hour. This residue C is then introduced into a vacuum distillation apparatus 101 heated by steam (not shown), and the inside of the distillation apparatus 101 is reduced to 4.9 kPa (absolute pressure) by a vacuum pump (not shown). Distillation was performed at 120 ° C. Then, cyclohexanone oxime A2 was distilled off at 9 parts by weight / hour, and tar content D as a distillation residue was discharged from the bottom of the vacuum distillation apparatus 101 at 1 part by weight / hour.

（実施例２）
実施例１で減圧蒸留器１０１にて留去させて得たシクロヘキサノンオキシムＡ２を用いて、図２に示すフローチャートに準じて、シクロヘキサノンオキシムの回収を行った。
留去されたシクロヘキサノンオキシムＡ２は、９０℃の熱水を用いた予備凝縮器１０２に導き、該予備凝縮器１０２で凝縮した液状シクロヘキサノンオキシムＡ３を回収するとともに、未凝縮のシクロヘキサノオキシムＡ４を９５℃に保温しつつ直接接触式凝縮器１０３に導入した。この直接接触式の凝縮器１０３は、連続的に投入したメタノールＥをポンプ１０４にて循環させ、凝縮器１０３の上部からスプレーノズル（図示せず）で噴霧するようになっており、導入されたシクロヘキサノンオキシムＡ４に対して冷却手段１０５で−６℃に冷却されたメタノールＥを噴霧して直接接触させることでシクロヘキサノンオキシムＡ４を凝縮させるものである。凝縮したシクロヘキサノンオキシムを含むメタノールは、循環途中でシクロヘキサノンオキシムのメタノール溶液Ａ５として抜き出した。なお、シクロヘキサノンオキシムＡ２およびＡ４は、真空ポンプ１０６により予備凝縮器１０２および直接接触式凝縮器１０３に導いた。 (Example 2)
Using cyclohexanone oxime A2 obtained by distilling off with the vacuum distillation apparatus 101 in Example 1, cyclohexanone oxime was recovered according to the flowchart shown in FIG.
The distilled cyclohexanone oxime A2 is led to a precondenser 102 using hot water at 90 ° C., and liquid cyclohexanone oxime A3 condensed in the precondenser 102 is recovered, and uncondensed cyclohexanooxime A4 is recovered as 95. It was directly introduced into the contact condenser 103 while keeping the temperature at 0 ° C. This direct contact type condenser 103 is configured such that methanol E continuously fed is circulated by a pump 104 and sprayed from above the condenser 103 by a spray nozzle (not shown). The cyclohexanone oxime A4 is condensed by spraying methanol E cooled to −6 ° C. by the cooling means 105 and bringing it into direct contact with the cyclohexanone oxime A4. Methanol containing the condensed cyclohexanone oxime was extracted as a methanol solution A5 of cyclohexanone oxime during the circulation. The cyclohexanone oxime A2 and A4 were led to the precondenser 102 and the direct contact condenser 103 by the vacuum pump 106.

（実施例３）
実施例１で減圧蒸留器１０１にて留去させて得たシクロヘキサノンオキシムＡ２を用いて、図３に示すフローチャートに準じて、シクロヘキサノンオキシムの回収を行う。
留去されたシクロヘキサノンオキシムＡ２は、真空ポンプ１０６により直接接触式凝縮器１０３に導く。この直接接触式の凝縮器１０３は、連続的に投入したメタノールＥをポンプ１０４にて循環させ、凝縮器１０３の上部からスプレーノズル（図示せず）で噴霧するようになっており、導入されたシクロヘキサノンオキシムＡ４に対して冷却手段１０５で−６℃に冷却されたメタノールＥを噴霧して直接接触させることでシクロヘキサノンオキシムＡ２を凝縮させるものである。凝縮したシクロヘキサノンオキシムを含むメタノールは、循環途中でシクロヘキサノンオキシムのメタノール溶液Ａ５として抜き出すことができる。 (Example 3)
Cyclohexanone oxime is recovered according to the flowchart shown in FIG. 3 using cyclohexanone oxime A2 obtained by distilling off using the vacuum distillation apparatus 101 in Example 1.
The distilled cyclohexanone oxime A2 is directly led to the contact condenser 103 by the vacuum pump 106. This direct contact type condenser 103 is configured such that methanol E continuously fed is circulated by a pump 104 and sprayed from above the condenser 103 by a spray nozzle (not shown). The cyclohexanone oxime A2 is condensed by spraying methanol E cooled to −6 ° C. by the cooling means 105 to the cyclohexanone oxime A4 and directly contacting it. The methanol containing the condensed cyclohexanone oxime can be extracted as a methanol solution A5 of cyclohexanone oxime during the circulation.

本発明のシクロヘキサノンオキシムの回収方法の一実施形態を示すフローチャートである。It is a flowchart which shows one Embodiment of the collection | recovery method of the cyclohexanone oxime of this invention. 本発明のシクロヘキサノンオキシムの回収方法の他の実施形態を示すフローチャートである。It is a flowchart which shows other embodiment of the collection | recovery method of the cyclohexanone oxime of this invention. 本発明のシクロヘキサノンオキシムの回収方法のさらに他の実施形態を示すフローチャートである。It is a flowchart which shows other embodiment of the collection | recovery method of the cyclohexanone oxime of this invention.

符号の説明Explanation of symbols

１００ 蒸発器
１０１ 減圧蒸留器
１０２ 予備凝縮器
１０３ 直接接触式凝縮器
１０４、１０６ ポンプ（真空ポンプ）
１０５ 冷却手段 DESCRIPTION OF SYMBOLS 100 Evaporator 101 Vacuum distillation apparatus 102 Precondenser 103 Direct contact type condenser 104,106 Pump (vacuum pump)
105 Cooling means

Claims (5)

液状シクロヘキサノンオキシムを加熱蒸発させてシクロヘキサノンオキシムガス(Ａ１)を得た後の残渣を、加熱蒸発させる際の圧力よりも低い圧力の下に蒸留し、前記残渣に含まれるシクロヘキサノンオキシムを回収する、ことを特徴とするシクロヘキサノンオキシムの回収方法。   The residue after the liquid cyclohexanone oxime is evaporated by heating to obtain cyclohexanone oxime gas (A1) is distilled under a pressure lower than the pressure at the time of evaporation by heating, and the cyclohexanone oxime contained in the residue is recovered. A process for recovering cyclohexanone oxime characterized by 前記蒸留は、１．４〜１０ｋＰａ（絶対圧力）の下で行う、請求項１記載のシクロヘキサノンオキシムの回収方法。   The method for recovering cyclohexanone oxime according to claim 1, wherein the distillation is performed under 1.4 to 10 kPa (absolute pressure). 前記残渣を蒸留することにより留去されたシクロヘキサノンオキシムガス(Ａ２)を、シクロヘキサノンオキシムを溶解しうる溶剤に接触させてシクロヘキサノンオキシム溶液とし、回収する、請求項１または２記載のシクロヘキサノンオキシムの回収方法。   The method for recovering cyclohexanone oxime according to claim 1 or 2, wherein cyclohexanone oxime gas (A2) distilled off by distillation of the residue is brought into contact with a solvent capable of dissolving cyclohexanone oxime to form a cyclohexanone oxime solution and recovered. . 前記残渣を蒸留することにより留去されたシクロヘキサノンオキシムガス(Ａ２)を、９０℃以上の冷却用媒体を用いた凝縮器で凝縮してシクロヘキサノンオキシム凝縮液（Ａ３）を得、同時に得られた未凝縮のシクロヘキサノンオキシムガス（Ａ４）を、シクロヘキサノンオキシムを溶解しうる溶剤に接触させてシクロヘキサノンオキシム溶液とし、回収する、請求項１または２記載のシクロヘキサノンオキシムの回収方法。   The cyclohexanone oxime gas (A2) distilled off by distilling the residue was condensed in a condenser using a cooling medium at 90 ° C. or higher to obtain a cyclohexanone oxime condensate (A3). The method for recovering cyclohexanone oxime according to claim 1 or 2, wherein the condensed cyclohexanone oxime gas (A4) is brought into contact with a solvent capable of dissolving cyclohexanone oxime to form a cyclohexanone oxime solution and recovered. 前記シクロヘキサノンオキシムガス(Ａ２)またはシクロヘキサノンオキシムガス（Ａ４）を、冷却体の表面で前記溶剤と接触させる、請求項３または４記載のシクロヘキサノンオキシムの回収方法。   The method for recovering cyclohexanone oxime according to claim 3 or 4, wherein the cyclohexanone oxime gas (A2) or cyclohexanone oxime gas (A4) is brought into contact with the solvent on the surface of a cooling body.
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JPH08283185A (en) * 1995-04-03 1996-10-29 Eastman Kodak Co Removal of dimethyl terephthalate from metanolysis vapor flow
JP2002284752A (en) * 2001-03-28 2002-10-03 Sumitomo Chem Co Ltd Method for evaporating cyclohexanone oxime
JP2003034674A (en) * 2001-06-28 2003-02-07 Enichem Spa Method for purifying cyclohexanone-oxime

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JPH08283185A (en) * 1995-04-03 1996-10-29 Eastman Kodak Co Removal of dimethyl terephthalate from metanolysis vapor flow
JP2002284752A (en) * 2001-03-28 2002-10-03 Sumitomo Chem Co Ltd Method for evaporating cyclohexanone oxime
JP2003034674A (en) * 2001-06-28 2003-02-07 Enichem Spa Method for purifying cyclohexanone-oxime

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