JP3211396B2 - Recovery method of acrylic acid and acetic acid - Google Patents
Recovery method of acrylic acid and acetic acidInfo
- Publication number
- JP3211396B2 JP3211396B2 JP22706392A JP22706392A JP3211396B2 JP 3211396 B2 JP3211396 B2 JP 3211396B2 JP 22706392 A JP22706392 A JP 22706392A JP 22706392 A JP22706392 A JP 22706392A JP 3211396 B2 JP3211396 B2 JP 3211396B2
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- acetic acid
- distillation column
- acrylic acid
- line
- column
- Prior art date
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Description
【０００１】[0001]
【産業上の利用分野】本発明は、プロピレン及び／又は
アクロレインを分子状酸素で接触酸化してアクリル酸を
製造する際に、副生する酢酸をアクリル酸と共に純度良
く回収する方法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for recovering acetic acid by-produced together with acrylic acid with high purity when producing acrylic acid by catalytically oxidizing propylene and / or acrolein with molecular oxygen.
【０００２】[0002]
【従来の技術】プロピレンおよび／またはアクロレイン
を水蒸気の存在下に固体触媒を用いて分子状酸素にて気
相接触酸化することによって得られる反応生成ガスは、
通常、冷却、洗浄されて水溶液として回収される。この
水溶液には主成分のアクリル酸のほかに、アクロレイ
ン、酢酸、その他のアルデヒド類等が含まれている。こ
のうち、アクロレインはアクリル酸と沸点差が大きいた
めに簡単に分離できる。また、その他のアルデヒド類は
生成量が極めて少なく、実用上の問題となることはほと
んどない。しかしながら、酢酸はアクリル酸に対して、
酸化触媒や反応条件によって異なるが、通常、１〜１５
ｗｔ％程度副生し、これを分離、除去することは有効成
分の回収および廃棄物負荷の低減の観点から重要であ
る。2. Description of the Related Art A reaction product gas obtained by subjecting propylene and / or acrolein to gas-phase catalytic oxidation with molecular oxygen using a solid catalyst in the presence of steam is as follows:
Usually, it is cooled, washed and recovered as an aqueous solution. This aqueous solution contains acrolein, acetic acid, other aldehydes and the like in addition to acrylic acid as a main component. Of these, acrolein can be easily separated because of its large boiling point difference from acrylic acid. In addition, the amount of other aldehydes produced is extremely small and hardly causes a practical problem. However, acetic acid is
Depending on the oxidation catalyst and reaction conditions, it is usually 1 to 15
It is important to separate and remove by-products of about wt% from the viewpoints of recovery of active ingredients and reduction of waste load.
【０００３】アクリル酸と酢酸を分離する方法として、
蒸留で直接分離する方法（特公昭４９−２４８９８
号）、アクリル酸を安定化させる効果があるといわれる
トルエン、エチルベンゼン、キシレンなどの共沸溶媒を
使用して共沸蒸留する方法（特開昭４９−７２１６号、
特公昭６３−１０６９１号、特開平３−１８１４４０
号、特公昭４１−１１２４７号）が知られている。[0003] As a method for separating acrylic acid and acetic acid,
Direct separation by distillation (JP-B-49-24898)
Azeotropic distillation using an azeotropic solvent such as toluene, ethylbenzene or xylene, which is said to have an effect of stabilizing acrylic acid (JP-A-49-7216,
JP-B-63-10691, JP-A-3-181440
No. JP-B-41-11247) is known.
【０００４】[0004]
【発明が解決しようとする課題】しかしながら、蒸留で
直接分離する方法は、アクリル酸と酢酸の沸点差が小さ
いことから、蒸留塔の還流比や段数を大幅に増加させな
ければばらず、更に酢酸分離塔においてアクリル酸の重
合物が蒸留塔内で生成しやすいという問題を有してい
る。従来の共沸蒸留する方法は、酢酸をアクリル酸から
分離することはできるが、酢酸を排水中に捨てることに
なり、排水負荷が大きくなり、また、方法によっては回
収酢酸中にアクリル酸が混入し、純度が低下すると同時
に、アクリル酸がロスしてしまい好ましい方法とは言い
難い。However, in the direct separation method by distillation, since the boiling point difference between acrylic acid and acetic acid is small, the reflux ratio and the number of stages in the distillation column must be greatly increased. There is a problem that a polymer of acrylic acid is easily formed in the distillation column in the separation column. With the conventional azeotropic distillation method, acetic acid can be separated from acrylic acid, but acetic acid is discarded in the wastewater, which increases the drainage load, and depending on the method, acrylic acid is mixed in the recovered acetic acid. However, at the same time as the purity is reduced, acrylic acid is lost, which is not a preferable method.
【０００５】本発明者はかかる問題のない粗アクリル酸
水溶液から精製アクリル酸及び酢酸を分離回収すること
を目的として鋭意検討した結果、第一蒸留塔で粗アクリ
ル酸水溶液から共沸脱水によって水を分離し、第二蒸留
塔で塔底からアクリル酸を取り出し、第三蒸留塔で実質
的にアクリル酸を含まない酢酸を留出させ、塔底液は第
一蒸留塔又は第二蒸留塔に循環し、第四蒸留塔で水を加
えて溶媒を留去し、塔底より酢酸を取り出すことによ
り、効率良く、高純度のアクリル酸及び酢酸を回収でき
ることを見出し、本発明に至った。The inventors of the present invention have conducted intensive studies for the purpose of separating and recovering purified acrylic acid and acetic acid from a crude acrylic acid aqueous solution free from such problems, and as a result, water was removed from the crude acrylic acid aqueous solution by azeotropic dehydration in the first distillation column. Separate, take out acrylic acid from the bottom in the second distillation column, distill acetic acid substantially free of acrylic acid in the third distillation column, circulate the bottom liquid to the first distillation column or the second distillation column Then, the present inventors have found that high-purity acrylic acid and acetic acid can be efficiently recovered by adding water in a fourth distillation column to distill off the solvent and removing acetic acid from the bottom of the column, thereby leading to the present invention.
【０００６】[0006]
【課題を解決するための手段】すなわち本発明は、
（１）プロピレン及び／又はアクロレインを分子状酸素
で接触酸化して生成するガスを冷却及び／又は水に吸収
して得られる粗アクリル水溶液又は該水溶液中のアルデ
ヒド類をストリッピングにより除去した水溶液及び酢酸
と水のそれぞれと共沸する溶媒を第一蒸留塔に供給し、
（２）第一蒸留塔の塔頂より供給液に含まれる実質的に
全ての水を同伴する一部の酢酸と共に留去し、酢酸及び
アクリル酸を塔底液として抜き出して第二蒸留塔に供給
し、（３）第二蒸留塔にて残り全ての酢酸とアクリル酸
の一部を塔頂より留出させて第三蒸留塔に供給し、塔底
より精製アクリル酸を回収し、（４）第三蒸留塔にて塔
頂より実質的にアクリル酸を含まない酢酸を留出させて
第四蒸留塔に供給し、塔底より酢酸及びアクリル酸を抜
き出して第一蒸留塔又は第二蒸留塔に循環し、（５）第
四蒸留塔にて塔頂に水を供給して溶媒を留去し、塔底よ
り精製酢酸を回収することを特徴とするアクリル酸及び
酢酸の回収方法である。That is, the present invention provides:
(1) a crude acrylic aqueous solution obtained by cooling and / or absorbing gas produced by catalytically oxidizing propylene and / or acrolein with molecular oxygen, and / or an aqueous solution obtained by removing aldehydes in the aqueous solution by stripping; A solvent that azeotropes with each of acetic acid and water is supplied to the first distillation column,
(2) From the top of the first distillation column, substantially all of the water contained in the feed solution is distilled off together with a portion of the accompanying acetic acid, and acetic acid and acrylic acid are withdrawn as a bottom solution and passed to the second distillation column. (3) In the second distillation column, all remaining acetic acid and part of acrylic acid are distilled off from the top and supplied to the third distillation column, and purified acrylic acid is recovered from the bottom of the column. ) Distilling acetic acid substantially free of acrylic acid from the top of the third distillation column and supplying it to the fourth distillation column, extracting acetic acid and acrylic acid from the bottom of the column, and removing the acetic acid and acrylic acid from the first distillation column or the second distillation column (5) A method for recovering acrylic acid and acetic acid, comprising: supplying water to the top of a fourth distillation column to distill off the solvent, and recovering purified acetic acid from the bottom of the column. .
【０００７】プロピレンまたはアクロレインを水蒸気の
存在下に固体触媒を用いて分子状酸素にて気相接触酸化
するとアクリル酸の他に、アクロレイン、酢酸やその他
のアルデヒド類が生成する。通常、反応生成ガスは冷却
及び／または水に吸収して粗アクリル酸水溶液として回
収される。用いる触媒の種類や反応条件によって異なる
が、酢酸はアクリル酸に対して約１〜１５％程度含まれ
る。When propylene or acrolein is oxidized in the gas phase with molecular oxygen using a solid catalyst in the presence of water vapor, acrolein, acetic acid and other aldehydes are produced in addition to acrylic acid. Usually, the reaction product gas is cooled and / or absorbed in water and recovered as a crude acrylic acid aqueous solution. Acetic acid is included in about 1 to 15% of acrylic acid, depending on the type of catalyst used and reaction conditions.
【０００８】酢酸と水のそれぞれと共沸する溶媒として
は、ベンゼン、トルエン、キシレン、エチルベンゼン、
シクロヘキサン、シクロヘキセン、メチルシクロヘキサ
ン、ヘプタン、オクタン及びこれらの混合物が用いられ
る。The solvents azeotropic with acetic acid and water include benzene, toluene, xylene, ethylbenzene,
Cyclohexane, cyclohexene, methylcyclohexane, heptane, octane and mixtures thereof are used.
【０００９】以下、本発明の実施態様を示す図１により
説明する。粗アクリル酸水溶液をライン５から、水と酢
酸のそれぞれと共沸する溶媒をライン７から第一蒸留塔
１に供給し共沸脱水蒸留を行う。塔頂より供給液に含ま
れる実質的に全ての水、一部の酢酸及び溶媒、さらには
少量のアクリル酸が同伴して留出する。留出液の溶媒層
は蒸留塔に還流し、水層はライン８から廃棄する。留出
した酢酸は水層に入り、廃棄される。その量は蒸留条件
にもよるが、第一蒸留塔に供給される量の２５〜３５％
程度になる。FIG. 1 shows an embodiment of the present invention. A crude acrylic acid aqueous solution is supplied to the first distillation column 1 from a line 5 and a solvent azeotropic with water and acetic acid from a line 7 to perform azeotropic dehydration distillation. From the top of the column, substantially all of the water, part of acetic acid and the solvent contained in the feed, and a small amount of acrylic acid are distilled off. The solvent layer of the distillate is refluxed to the distillation column, and the aqueous layer is discarded from the line 8. Distilled acetic acid enters the aqueous layer and is discarded. The amount depends on the distillation conditions, but 25 to 35% of the amount supplied to the first distillation column.
About.
【００１０】アクリル酸、酢酸および溶媒からなる塔底
液はライン６から第二蒸留塔２に供給し、更に第三蒸留
塔３の塔底液をライン１２を経て循環、供給し、留出液
を一部還流しながら蒸留し、塔頂から第二蒸留塔２へ供
給した酢酸及び溶媒の実質的に全量をアクリル酸の一部
と共に留出させる。塔底液は酢酸及び溶媒を殆ど含まな
い精製アクリル酸であり、ライン１０から抜き出し、必
要により更に精製して製品のアクリル酸とする。A bottom solution comprising acrylic acid, acetic acid and a solvent is supplied from a line 6 to a second distillation column 2, and the bottom solution of a third distillation column 3 is circulated and supplied via a line 12, and a distillate Is distilled under partial reflux, and substantially all of the acetic acid and the solvent supplied from the top to the second distillation column 2 are distilled off together with a part of acrylic acid. The bottom liquid is purified acrylic acid containing almost no acetic acid and solvent and is withdrawn from the line 10 and, if necessary, further purified to obtain acrylic acid as a product.
【００１１】アクリル酸、酢酸および溶媒からなる第二
蒸留塔の留出液はライン１１から第三蒸留塔３に供給
し、留出液を一部還流しながら蒸留し、塔頂から実質的
にアクリル酸を含まない酢酸と溶媒をほぼ共沸組成に近
い組成で留出させる。留出液にアクリル酸が混入すると
アクリル酸がロスになるだけでなく酢酸の純度低下につ
ながるので出来るだけ留出させないようにする必要があ
る。アクリル酸、酢酸および溶媒からなる塔底液はライ
ン１２から第一蒸留塔又は第二蒸留塔へ循環する。何れ
の塔へ循環するかは蒸留塔の分離能力、エネルギー使用
量等を勘案して適宜選択される。The distillate of the second distillation column comprising acrylic acid, acetic acid and a solvent is supplied from a line 11 to a third distillation column 3, and the distillate is partially distilled under reflux, and substantially distilled from the top of the column. Acrylic acid-free acetic acid and a solvent are distilled off at a composition close to the azeotropic composition. If acrylic acid is mixed in the distillate, acrylic acid is lost as well as the purity of acetic acid is reduced. Therefore, it is necessary to avoid distilling as much as possible. A bottoms liquid composed of acrylic acid, acetic acid and a solvent is circulated from a line 12 to a first distillation column or a second distillation column. Which column to circulate is appropriately selected in consideration of the separation capacity of the distillation column, the amount of energy used, and the like.
【００１２】酢酸と溶媒からなる第三蒸留塔の留出液は
ライン１３から第四蒸留塔に供給し、溶媒を水と共沸除
去させるためにライン１６から水を供給して蒸留を行
い、塔頂から第四蒸留塔に供給される実質的にすべての
溶媒と水を留出させ、水は蒸留塔へ還流し、溶媒はライ
ン１７からライン７を経て第一蒸留塔へ循環する。塔底
のライン１５から精製酢酸を取り出す。酢酸の濃度は９
５％以上、更には９８％以上にすることが可能である。The distillate from the third distillation column comprising acetic acid and a solvent is supplied to a fourth distillation column from a line 13, and water is supplied from a line 16 to azeotropically remove the solvent with water, and distillation is performed. Substantially all of the solvent and water fed to the fourth distillation column from the top are distilled off, the water is refluxed to the distillation column, and the solvent is circulated from line 17 through line 7 to the first distillation column. The purified acetic acid is taken out from the bottom line 15. Acetic acid concentration is 9
It can be 5% or more, and even 98% or more.
【００１３】第二蒸留塔の塔底液である精製アクリル酸
に酢酸の混入するのを出来るだけ少なくするために、ラ
イン９で示す第一蒸留塔の塔底液の供給位置よりも下部
に溶媒を追加してもよい。また、第三蒸留塔において、
アクリル酸の留出を抑制しつつ溶媒の留出を促進するた
めに、ライン１４で示すように回収した酢酸の一部を第
三蒸留塔に循環してもよい。In order to minimize the incorporation of acetic acid into the purified acrylic acid, which is the bottom liquid of the second distillation column, the solvent is placed below the supply position of the bottom liquid of the first distillation column shown in line 9. May be added. In the third distillation column,
In order to promote the distillation of the solvent while suppressing the distillation of acrylic acid, a part of the collected acetic acid may be circulated to the third distillation column as shown by the line 14.
【００１４】[0014]
【発明の効果】本発明の方法により、プロピレン及び／
又はアクロレインの酸化生成物から効率的に純度良くア
クリル酸及び酢酸を回収することができる。According to the method of the present invention, propylene and / or
Alternatively, acrylic acid and acetic acid can be efficiently and efficiently recovered from the oxidation product of acrolein.
【００１５】[0015]
【実施例】以下、本発明を実施例で詳細に説明するが、
本発明はこの実施例に限定されない。 実施例１ 図１に示すフローでアクリル酸及び酢酸の回収を行う。
アクリル酸５７．５ｗｔ％、酢酸２．９ｗｔ％を含む粗
アクリル酸水溶液を第一蒸留塔１にライン５から１０．
９ｋｇ／Ｈで、同時に共沸溶媒としてトルエンをライン
７から０．５８ｋｇ／Ｈで供給し、塔頂圧力１６０ｍｍ
Ｈｇ、塔頂温度４６℃で蒸留を行う。留出液の溶媒層は
蒸留塔へ還流し、水層はライン８から４．４ｋｇ／Ｈで
抜き出す。水層にはトルエンが０．５％、酢酸が１．９
％、アクリル酸が０．０５％含まれる。Hereinafter, the present invention will be described in detail with reference to Examples.
The present invention is not limited to this embodiment. Example 1 Acrylic acid and acetic acid are collected according to the flow shown in FIG.
The crude acrylic acid aqueous solution containing 57.5% by weight of acrylic acid and 2.9% by weight of acetic acid was introduced into the first distillation column 1 through lines 5 to 10.
At the same time, toluene was supplied at 0.58 kg / H from line 7 as an azeotropic solvent at a pressure of 160 mm
Distillation is carried out at Hg and at an overhead temperature of 46 ° C. The solvent layer of the distillate is refluxed to the distillation column, and the aqueous layer is withdrawn from line 8 at 4.4 kg / H. 0.5% of toluene and 1.9 of acetic acid in the aqueous layer
% Acrylic acid and 0.05%.
【００１６】塔底液はトルエンを７．９％、酢酸を３．
３％、アクリル酸を８８．８％含み、ライン６を経由し
て第二蒸留塔２へ供給する。更に、トルエンを４８．７
％、酢酸を１８．０％、アクリル酸を３３．１％を含む
第三蒸留塔の塔底液を第二蒸留塔に循環、供給し、塔頂
圧力８０ｍｍＨｇ、塔頂温度５２℃、還流比３．５で蒸
留を行う。トルエン６７．７％、酢酸９．４ｗｔ％、ア
クリル酸２２．８％を含む留出液を３．１ｋｇ／Ｈで、
塔底からは酢酸濃度が３０００ｐｐｍ以下の精製アクリ
ル酸を６．３ｋｇ／Ｈで得る。The bottom liquid is 7.9% of toluene and 3.09% of acetic acid.
It contains 3% and 88.8% of acrylic acid and is supplied to the second distillation column 2 via the line 6. Further, toluene was added to 48.7.
%, Acetic acid 18.0%, acrylic acid 33.1%, the bottom liquid of the third distillation column is circulated and supplied to the second distillation column, the top pressure is 80 mmHg, the top temperature is 52 ° C., and the reflux ratio is Distill at 3.5. A distillate containing 67.7% of toluene, 9.4% by weight of acetic acid, and 22.8% of acrylic acid at 3.1 kg / H,
6.3 kg / H of purified acrylic acid having an acetic acid concentration of 3000 ppm or less is obtained from the bottom of the column.
【００１７】第二蒸留塔の留出液をライン１１を経て第
三蒸留塔へ供給し、塔頂圧力２４０ｍｍＨｇ、塔頂温度
７１℃、還流比４．０で蒸留を行う。塔頂からトルエン
を７０．５％、酢酸を２９．２％を含み、アクリル酸が
３００ｐｐｍ以下の留出液を０．８ｋｇ／Ｈで、トルエ
ンを４８．７％、酢酸を１８．０％、アクリル酸を３
３．１％を含む塔底液を得る。塔底液はライン１２をへ
て第二蒸留塔へ循環する。The distillate from the second distillation column is supplied to the third distillation column via the line 11, and distillation is performed at a top pressure of 240 mmHg, a top temperature of 71 ° C., and a reflux ratio of 4.0. A distillate containing 70.5% of toluene and 29.2% of acetic acid from the top of the column, and a distillate containing 300 ppm or less of acrylic acid at 0.8 kg / H, 48.7% of toluene, 18.0% of acetic acid, 3 acrylic acid
A bottoms liquid containing 3.1% is obtained. The bottom liquid is circulated through line 12 to the second distillation column.
【００１８】第三蒸留塔の留出液を第四蒸留塔へ供給
し、共沸剤として水０．１４ｋｇ／Ｈをライン１６から
塔頂に供給して塔頂圧力３００ｍｍＨｇで蒸留し、留出
液の水層は蒸留塔へ還流し、溶媒はライン１７からライ
ン７を経て第一蒸留塔へ循環する。塔底のライン１５か
ら水１．８ｗｔ％を含む純度９８ｗｔ％以上の酢酸を
０．２３ｋｇ／Ｈで回収する。なお、回収酢酸中のアク
リル酸は０．１ｗｔ％以下である。The distillate from the third distillation column is supplied to the fourth distillation column, and 0.14 kg / H of water as an azeotropic agent is supplied from the line 16 to the top of the column to distill it at a top pressure of 300 mmHg. The aqueous layer of the liquid is refluxed to the distillation column, and the solvent is circulated from the line 17 to the first distillation column via the line 7. Acetic acid having a purity of 98% by weight or more and containing 1.8% by weight of water is recovered from the bottom line 15 at a rate of 0.23 kg / H. In addition, acrylic acid in the recovered acetic acid is 0.1 wt% or less.
【００１９】実施例２ 図１に示すフローで実施例１と同様にアクリル酸及び酢
酸の回収を行う。アクリル酸５７．５ｗｔ％、酢酸２．
９ｗｔ％を含む粗アクリル酸水溶液を第一蒸留塔１にラ
イン５から１０．９ｋｇ／Ｈで、同時に共沸溶媒として
トルエンをライン７から０．５８ｋｇ／Ｈで供給し、塔
頂圧力１６０ｍｍＨｇ、塔頂温度４６℃で蒸留を行う。
留出液の溶媒層は蒸留塔へ還流し、水層はライン８から
４．４ｋｇ／Ｈで抜き出す。水層にはトルエンが０．５
％、酢酸が１．９％、アクリル酸が０．０５％含まれ
る。Example 2 Acrylic acid and acetic acid are recovered in the same manner as in Example 1 according to the flow shown in FIG. Acrylic acid 57.5 wt%, acetic acid 2.
A crude acrylic acid aqueous solution containing 9 wt% is supplied to the first distillation column 1 from the line 5 at 10.9 kg / H, and at the same time, toluene is supplied as an azeotropic solvent from the line 7 at 0.58 kg / H. Distillation is carried out at a top temperature of 46 ° C.
The solvent layer of the distillate is refluxed to the distillation column, and the aqueous layer is withdrawn from line 8 at 4.4 kg / H. 0.5 parts toluene in water layer
%, Acetic acid 1.9% and acrylic acid 0.05%.
【００２０】塔底液はトルエンを７．９％、酢酸を３．
３％、アクリル酸を８８．８％含み、ライン６を経由し
て第二蒸留塔２へ、トルエンを５７．４％、酢酸を３．
０％、アクリル酸を３９．６％を含む第三蒸留塔の塔底
液を第二蒸留塔に循環、供給する。更に、ライン９から
トルエンを０．５ｋｇ／Ｈで供給し、塔頂圧力８０ｍｍ
Ｈｇ、塔頂温度５４℃、還流比３．２で蒸留を行う。ト
ルエン６７．７％、酢酸９．４ｗｔ％、アクリル酸２
２．８％を含む留出液を３．１ｋｇ／Ｈで、塔底からは
酢酸濃度が１０００ｐｐｍ以下の精製アクリル酸を６．
３ｋｇ／Ｈで得る。The bottom liquid is 7.9% toluene and acetic acid 3.
Containing 38.8% of acrylic acid and 88.8% of acrylic acid;
The bottom liquid of the third distillation column containing 0% and 39.6% of acrylic acid is circulated and supplied to the second distillation column. Further, toluene was supplied at a rate of 0.5 kg / H from a line 9 and a top pressure was 80 mm.
Distillation is carried out at Hg, a top temperature of 54 ° C. and a reflux ratio of 3.2. Toluene 67.7%, acetic acid 9.4 wt%, acrylic acid 2
3.1 kg / H of a distillate containing 2.8% and purified acrylic acid having an acetic acid concentration of 1000 ppm or less from the bottom of the column.
Obtained at 3 kg / H.
【００２１】第二蒸留塔の留出液をライン１１を経て第
三蒸留塔へ、更にライン１４を経て酢酸を０．２ｋｇ／
Ｈで供給し、塔頂圧力２４０ｍｍＨｇ、塔頂温度６９
℃、還流比５．３で蒸留を行う。塔頂からトルエンを６
９．３％、酢酸を３０．５％を含み、アクリル酸が３０
０ｐｐｍ以下の留出液を１．５ｋｇ／Ｈで、トルエンを
５７．４％、酢酸を３．０％、アクリル酸を３９．６％
を含む塔底液を得た。塔底液はライン１２をへて第二蒸
留塔へ循環する。The distillate of the second distillation column is sent to the third distillation column via the line 11 and 0.2 kg / acetic acid is further fed via the line 14.
H, top pressure 240 mmHg, top temperature 69
The distillation is carried out at a temperature of 5.3 ° C. and a reflux ratio of 5.3. 6 toluene from top
9.3%, acetic acid 30.5%, acrylic acid 30
A distillate of 0 ppm or less is 1.5 kg / H, 57.4% of toluene, 3.0% of acetic acid, and 39.6% of acrylic acid.
Was obtained. The bottom liquid is circulated through line 12 to the second distillation column.
【００２２】第三蒸留塔の留出液を第四蒸留塔へ供給
し、共沸剤として水０．２６ｋｇ／Ｈをライン１６から
塔頂に供給して塔頂圧力３００ｍｍＨｇで蒸留し、留出
液の水層は蒸留塔へ還流し、溶媒はライン１７からライ
ン７を経て第一蒸留塔へ循環する。塔底のライン１５か
ら水１．８ｗｔ％を含む純度９８ｗｔ％以上の酢酸を
０．４６ｋｇ／Ｈで回収した。なお、回収酢酸中のアク
リル酸は０．１ｗｔ％以下である。The distillate from the third distillation column is supplied to the fourth distillation column, and 0.26 kg / H2 of water as an azeotropic agent is supplied from the line 16 to the top of the column to distill it at a top pressure of 300 mmHg. The aqueous layer of the liquid is refluxed to the distillation column, and the solvent is circulated from the line 17 to the first distillation column via the line 7. Acetic acid having a purity of 98% by weight or more and containing 1.8% by weight of water was recovered from line 15 at the bottom of the column at 0.46 kg / H. In addition, acrylic acid in the recovered acetic acid is 0.1 wt% or less.
【００２３】実施例３ 図１に示すフローでアクリル酸及び酢酸の回収を行う。
アクリル酸５７．５ｗｔ％、酢酸２．９ｗｔ％を含む粗
アクリル酸水溶液を第一蒸留塔１にライン５から１０．
９ｋｇ／Ｈで、同時に共沸溶媒としてトルエンをライン
７から０．５７ｋｇ／Ｈで供給し、更にトルエンを５
５．８％、酢酸を１３．８％、アクリル酸を３０．３％
を含む第三蒸留塔の塔底液を第一蒸留塔に循環、供給
し、塔頂圧力１６０ｍｍＨｇ、塔頂温度４６℃で蒸留を
行う。留出液の溶媒層は蒸留塔へ還流し、水層はライン
８から４．４ｋｇ／Ｈで抜き出す。水層にはトルエンが
０．４％、酢酸が２．０％、アクリル酸が０．０５％含
まれる。Example 3 Acrylic acid and acetic acid are recovered according to the flow shown in FIG.
The crude acrylic acid aqueous solution containing 57.5% by weight of acrylic acid and 2.9% by weight of acetic acid was introduced into the first distillation column 1 through lines 5 to 10.
At the same time, toluene was supplied at 0.57 kg / H from line 7 as an azeotropic solvent, and toluene was further added at 5 kg / H.
5.8%, acetic acid 13.8%, acrylic acid 30.3%
Is circulated and supplied to the first distillation column, and distillation is performed at a top pressure of 160 mmHg and a top temperature of 46 ° C. The solvent layer of the distillate is refluxed to the distillation column, and the aqueous layer is withdrawn from line 8 at 4.4 kg / H. The aqueous layer contains 0.4% toluene, 2.0% acetic acid, and 0.05% acrylic acid.
【００２４】塔底液はトルエンを１８．８％、酢酸を
５．７％、アクリル酸を７５．５％含み、ライン６を経
由して第二蒸留塔２へ供給する。塔頂圧力８０ｍｍＨ
ｇ、塔頂温度５２℃、還流比４．０で蒸留を行う。トル
エン、酢酸、アクリル酸を含む留出液を２．１ｋｇ／Ｈ
で、塔底からは酢酸濃度が３０００ｐｐｍ以下の精製ア
クリル酸を６．３ｋｇ／Ｈで得る。The bottom liquid contains 18.8% of toluene, 5.7% of acetic acid and 75.5% of acrylic acid, and is supplied to the second distillation column 2 via the line 6. Top pressure 80mmH
g, distillation at a top temperature of 52 ° C. and a reflux ratio of 4.0. 2.1 kg / H of distillate containing toluene, acetic acid and acrylic acid
Thus, 6.3 kg / H of purified acrylic acid having an acetic acid concentration of 3000 ppm or less is obtained from the bottom of the column.
【００２５】第二蒸留塔の留出液をライン１１を経て第
三蒸留塔へ供給し、塔頂圧力２４０ｍｍＨｇ、塔頂温度
７１℃、還流比５．０で蒸留を行う。塔頂からトルエン
を７０．５％、酢酸を２９．２％を含み、アクリル酸が
３００ｐｐｍ以下の留出液を０．８ｋｇ／Ｈで、トルエ
ンを５５．８％、酢酸を１３．８％、アクリル酸を３
０．３％を含む塔底液を得る。塔底液はライン１２をへ
て第一蒸留塔へ循環する。The distillate from the second distillation column is supplied to the third distillation column via the line 11, and distillation is performed at a top pressure of 240 mmHg, a top temperature of 71 ° C., and a reflux ratio of 5.0. A distillate containing 70.5% of toluene, 29.2% of acetic acid, and a distillate containing 300 ppm or less of acrylic acid at 0.8 kg / H from the top of the column, 55.8% of toluene, 13.8% of acetic acid, 3 acrylic acid
A bottoms solution containing 0.3% is obtained. The bottom liquid is circulated through line 12 to the first distillation column.
【００２６】第三蒸留塔の留出液を第四蒸留塔へ供給
し、共沸剤として水０．１４ｋｇ／Ｈをライン１６から
塔頂に供給して塔頂圧力３００ｍｍＨｇで蒸留し、留出
液の水層は蒸留塔へ還流し、溶媒はライン１７からライ
ン７を経て第一蒸留塔へ循環する。塔底のライン１５か
ら水１．８ｗｔ％を含む純度９８ｗｔ％以上の酢酸を
０．２３ｋｇ／Ｈで回収する。なお、回収酢酸中のアク
リル酸は０．１ｗｔ％以下である。The distillate from the third distillation column is supplied to the fourth distillation column, and 0.14 kg / H of water as an azeotropic agent is supplied from the line 16 to the top of the column to distill it at a top pressure of 300 mmHg. The aqueous layer of the liquid is refluxed to the distillation column, and the solvent is circulated from the line 17 to the first distillation column via the line 7. Acetic acid having a purity of 98% by weight or more and containing 1.8% by weight of water is recovered from the bottom line 15 at a rate of 0.23 kg / H. In addition, acrylic acid in the recovered acetic acid is 0.1 wt% or less.
【００２７】実施例４ 図１に示すフローで実施例１と同様にアクリル酸及び酢
酸の回収を行う。アクリル酸５６．３ｗｔ％、酢酸３．
２ｗｔ％を含む粗アクリル酸水溶液を第一蒸留塔１にラ
イン５から０．３９ｋｇ／Ｈで、同時に共沸溶媒として
トルエンをライン７から０．０３ｋｇ／Ｈで供給し、塔
頂圧力１６０ｍｍＨｇ、塔頂温度４６℃で蒸留を行う。
留出液の溶媒層は蒸留塔へ還流し、水層はライン８から
０．１６ｋｇ／Ｈで抜き出す。水層の酢酸は２．０％、
アクリル酸が０．３％以下である。Example 4 Acrylic acid and acetic acid are recovered in the same manner as in Example 1 according to the flow shown in FIG. 56.3 wt% acrylic acid, acetic acid 3.
A crude acrylic acid aqueous solution containing 2 wt% is supplied to the first distillation column 1 from the line 5 at 0.39 kg / H, and at the same time, toluene is supplied as an azeotropic solvent from the line 7 at 0.03 kg / H. Distillation is carried out at a top temperature of 46 ° C.
The solvent layer of the distillate is refluxed to the distillation column, and the aqueous layer is withdrawn from line 8 at 0.16 kg / H. Acetic acid in the aqueous layer is 2.0%,
Acrylic acid is 0.3% or less.
【００２８】塔底液０．２６ｋｇ／Ｈはトルエンを１
１．３％、酢酸を３．６％、アクリル酸を７７．３％含
み、ライン６を経由して第二蒸留塔２へ、トルエンを５
５．４％、酢酸を３．８％、アクリル酸を４０．８％を
含む第三蒸留塔の塔底液０．０７７ｋｇ／Ｈを第二蒸留
塔に循環、供給する。更に、ライン９からトルエンを
０．０１５ｋｇ／Ｈで供給し、塔頂圧力８０ｍｍＨｇ、
塔頂温度５５℃、還流比４．０で蒸留を行う。トルエン
６６．６％、酢酸９．１ｗｔ％、アクリル酸２４．２％
を含む留出液を０．１３ｋｇ／Ｈで、塔底からは酢酸濃
度が０．１％以下の精製アクリル酸を０．３ｋｇ／Ｈで
得る。The bottom liquid of 0.26 kg / H contains 1 part of toluene.
1.3%, acetic acid 3.6%, acrylic acid 77.3%, toluene 5 to the second distillation column 2 via line 6
0.077 kg / H of the bottom liquid of the third distillation column containing 5.4%, 3.8% of acetic acid and 40.8% of acrylic acid is circulated and supplied to the second distillation column. Further, toluene was supplied at 0.015 kg / H from the line 9 and the pressure at the top of the column was 80 mmHg.
Distillation is performed at an overhead temperature of 55 ° C. and a reflux ratio of 4.0. Toluene 66.6%, acetic acid 9.1 wt%, acrylic acid 24.2%
Is obtained at 0.13 kg / H, and purified acrylic acid having an acetic acid concentration of 0.1% or less is obtained at 0.3 kg / H from the bottom of the column.
【００２９】第二蒸留塔の留出液をライン１１を経て第
三蒸留塔へ、更にライン１４を経て酢酸を０．０１ｋｇ
／Ｈで供給し、塔頂圧力２４０ｍｍＨｇ、塔頂温度７０
℃、還流比７．０で蒸留を行う。塔頂からトルエンを６
９．９％、酢酸を３０．０％を含み、アクリル酸が５０
０ｐｐｍ以下の留出液を０．０６３ｋｇ／Ｈで、トルエ
ンを５５．４％、酢酸を３．８％、アクリル酸を４０．
８％を含む塔底液を得る。塔底液はライン１２をへて第
二蒸留塔へ循環する。The distillate from the second distillation column is sent to the third distillation column via the line 11, and 0.01 kg of acetic acid is sent via the line 14.
/ H, overhead pressure 240 mmHg, overhead temperature 70
Distillation is carried out at a temperature of 70 ° C. and a reflux ratio of 7.0. 6 toluene from top
Contains 9.9%, 30.0% acetic acid, 50% acrylic acid
0.063 kg / H of a distillate of 0 ppm or less, 55.4% of toluene, 3.8% of acetic acid, and 40.
A bottoms liquid containing 8% is obtained. The bottom liquid is circulated through line 12 to the second distillation column.
【００３０】第三蒸留塔の留出液を第四蒸留塔へ供給
し、共沸剤として水をライン１６から塔頂に供給して塔
頂圧力３００ｍｍＨｇで蒸留し、留出液の水層は蒸留塔
へ還流し、溶媒はライン１７からライン７を経て第一蒸
留塔へ循環する。塔底のライン１５から水１．８ｗｔ％
を含む純度９８ｗｔ％以上の酢酸を０．０１８ｋｇ／Ｈ
で得る。なお、回収酢酸中のアクリル酸は０．２ｗｔ％
以下である。The distillate from the third distillation column is supplied to the fourth distillation column, water is supplied as an azeotropic agent from the line 16 to the top and distilled at a top pressure of 300 mmHg. Reflux to the distillation column and the solvent circulates from line 17 via line 7 to the first distillation column. 1.8 wt% of water from the bottom line 15
Acetic acid with a purity of 98 wt% or more containing 0.018 kg / H
Get in. Acrylic acid in the recovered acetic acid was 0.2 wt%
It is as follows.
【図１】本発明の実施態様を示す図である。FIG. 1 is a diagram showing an embodiment of the present invention.
１ 第一蒸留塔 ２ 第二蒸留塔 ３ 第三蒸留塔 ４ 第四蒸留塔 ５ 第一蒸留塔への供給ライン ６ 第一蒸留塔塔底液の抜き出しライン ７ 溶媒の供給ライン ８ 水の排出ライン ９ 溶媒の追加供給ライン １０ 第二蒸留塔塔底液（精製アクリル酸）の抜き出し
ライン １１ 第三蒸留塔への供給ライン １２ 第三蒸留塔塔底液の抜き出しライン １３ 第四蒸留塔への供給ライン １４ 酢酸の循環ライン １５ 第四蒸留塔塔底液（精製酢酸）の抜き出しライン １６ 水の供給ライン １７ 溶媒の取り出しラインDESCRIPTION OF SYMBOLS 1 1st distillation tower 2 2nd distillation tower 3 3rd distillation tower 4 4th distillation tower 5 Supply line to 1st distillation tower 6 Extraction line of bottom liquid of 1st distillation tower 7 Solvent supply line 8 Water discharge line 9 Additional supply line of solvent 10 Extraction line of bottom liquid (purified acrylic acid) of second distillation column 11 Supply line to third distillation column 12 Extraction line of bottom liquid of third distillation column 13 Supply to fourth distillation column Line 14 Circulation line of acetic acid 15 Fourth distillation tower bottom liquid (purified acetic acid) extraction line 16 Water supply line 17 Solvent extraction line
───────────────────────────────────────────────────── フロントページの続き (72)発明者 安田 稔 愛媛県新居浜市惣開町５番１号 住友化 学工業株式会社内 (56)参考文献 特開 平３−181440（ＪＰ，Ａ) 特開 昭56−90034（ＪＰ，Ａ) (58)調査した分野(Int.Cl.7，ＤＢ名) C07C 51/46 C07C 53/08 C07C 57/07 ────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Minoru Yasuda 5-1 Sokai-cho, Niihama-shi, Ehime Sumitomo Chemical Industries, Ltd. (56) References JP-A-3-181440 (JP, A) JP-A Sho 56-90034 (JP, A) (58) Fields investigated (Int. Cl. 7 , DB name) C07C 51/46 C07C 53/08 C07C 57/07
Claims (4)
ンを分子状酸素で接触酸化して生成するガスを冷却及び
／又は水に吸収して得られる粗アクリル水溶液又は該水
溶液中のアルデヒド類をストリッピングにより除去した
水溶液及び酢酸と水のそれぞれと共沸する溶媒を第一蒸
留塔に供給し、（２）第一蒸留塔の塔頂より供給液に含
まれる実質的に全ての水を同伴する一部の酢酸と共に留
去し、酢酸及びアクリル酸を塔底液として抜き出して第
二蒸留塔に供給し、（３）第二蒸留塔にて残り全ての酢
酸とアクリル酸の一部を塔頂より留出させて第三蒸留塔
に供給し、塔底より精製アクリル酸を回収し、（４）第
三蒸留塔にて塔頂より実質的にアクリル酸を含まない酢
酸を留出させて第四蒸留塔に供給し、塔底より酢酸及び
アクリル酸を抜き出して第一蒸留塔又は第二蒸留塔に循
環し、（５）第四蒸留塔にて塔頂に水を供給して溶媒を
留去し、塔底より精製酢酸を回収することを特徴とする
アクリル酸及び酢酸の回収方法。1. A method for stripping a crude acrylic aqueous solution obtained by cooling and / or absorbing a gas generated by catalytically oxidizing propylene and / or acrolein with molecular oxygen and / or water, or an aldehyde in the aqueous solution. (2) supplying the aqueous solution removed by the method and a solvent azeotropic with each of acetic acid and water to the first distillation column, and (2) entraining substantially all of the water contained in the feed liquid from the top of the first distillation column. Of acetic acid and acrylic acid are withdrawn as a bottom liquid and supplied to the second distillation column. (3) In the second distillation column, all remaining acetic acid and acrylic acid are partially removed from the top of the column. Distilled and supplied to the third distillation column, purified acrylic acid is recovered from the bottom of the column, and (4) acetic acid substantially free of acrylic acid is distilled from the top of the third distillation column to form the fourth Feed to distillation column and extract acetic acid and acrylic acid from bottom of column (5) supplying water to the top of the fourth distillation column to distill off the solvent, and recovering purified acetic acid from the bottom of the fourth distillation column. Method for recovering acrylic acid and acetic acid.
給位置よりも下部に溶媒を追加供給すること及び／又は
第四蒸留塔の塔底の精製酢酸の一部を第三蒸留塔に循環
することを特徴とする請求項１記載のアクリル酸及び酢
酸の回収方法。2. A solvent is additionally supplied below a position at which a bottom liquid of the first distillation column is supplied to the second distillation column, and / or a part of the purified acetic acid at the bottom of the fourth distillation column is removed. 2. The method for recovering acrylic acid and acetic acid according to claim 1, wherein the acrylic acid and acetic acid are circulated through a tristillation column.
項２記載の酢酸の回収方法。3. The method for recovering acetic acid according to claim 1, wherein the solvent is toluene.
項１又は請求項２記載の酢酸の回収方法。4. The method for recovering acetic acid according to claim 1, wherein the concentration of the purified acetic acid is 95% or more.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP22706392A JP3211396B2 (en) | 1992-08-26 | 1992-08-26 | Recovery method of acrylic acid and acetic acid |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP22706392A JP3211396B2 (en) | 1992-08-26 | 1992-08-26 | Recovery method of acrylic acid and acetic acid |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0672944A JPH0672944A (en) | 1994-03-15 |
| JP3211396B2 true JP3211396B2 (en) | 2001-09-25 |
Family
ID=16854952
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP22706392A Expired - Fee Related JP3211396B2 (en) | 1992-08-26 | 1992-08-26 | Recovery method of acrylic acid and acetic acid |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3211396B2 (en) |
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| JPH0672944A (en) | 1994-03-15 |
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