JPS62120341A - Purification of methacrylic acid - Google Patents

Purification of methacrylic acid

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Publication number
JPS62120341A
JPS62120341A JP25872185A JP25872185A JPS62120341A JP S62120341 A JPS62120341 A JP S62120341A JP 25872185 A JP25872185 A JP 25872185A JP 25872185 A JP25872185 A JP 25872185A JP S62120341 A JPS62120341 A JP S62120341A
Authority
JP
Japan
Prior art keywords
methacrylic acid
acetic acid
extraction
semipermeable membrane
acid
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
Application number
JP25872185A
Other languages
Japanese (ja)
Other versions
JPH0694433B2 (en
Inventor
Kozo Iwasaki
岩崎 晃三
Morimasa Kuragano
倉賀野 守正
Minoru Koshibe
越部 実
Osamu Kido
木戸 修
Hirozo Segawa
瀬川 博三
Katsuji Yoguchi
與口 勝治
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Kyowa Gas Chemical Industry Co Ltd
Mitsui Toatsu Chemicals Inc
Original Assignee
Kyowa Gas Chemical Industry Co Ltd
Mitsui Toatsu Chemicals Inc
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Kyowa Gas Chemical Industry Co Ltd, Mitsui Toatsu Chemicals Inc filed Critical Kyowa Gas Chemical Industry Co Ltd
Priority to JP60258721A priority Critical patent/JPH0694433B2/en
Publication of JPS62120341A publication Critical patent/JPS62120341A/en
Publication of JPH0694433B2 publication Critical patent/JPH0694433B2/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

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  • Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)

Abstract

PURPOSE:Isobutylene, tert.-butanol, methacrolein or isobutyl aldehyde is catalytically oxidized with O2 in the presence of steam, and the resultant methacrylic acid is efficiently purified by combination of treatment with a semipermeable membrane and extraction with isopropyl acetate. CONSTITUTION:The catalytic oxidation of isobutylene, tert.-butanol, methacrolein or isobutyl aldehyde is carried out with an oxygen-containing gas in the presence of steam, the resultant reaction mixture gas (containing acetic acid as a major impurity) is cooled down to form aqueous methacrylic acid. The solution is brought into contact with a semipermeable membrane at 5-50 deg.C at 20-60kg/cm<2>. The filtrate is extracted with isopropyl acetate to collect methacrylic acid acetic acid simultaneously and methacrylic acid is purified.

Description

【発明の詳細な説明】 〔産業上の利用分野〕 この発明は、メタクリル酸の改良された精製法に間する
ものである。さらに詳しくは、イソブチレン、第3級ブ
タノール、メタクロレインまたはインブチルアルデヒF
:ヲ水蒸気の存在下に分子状酸素含有ガスにより接触酸
化して得られるメタクリルMIFr半透過膜処理と酢酸
イソプロピルによる抽出の組合せにより効率よく精製す
る方法に関する。
DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] This invention relates to an improved method for purifying methacrylic acid. More specifically, isobutylene, tertiary butanol, methacrolein or inbutyraldehyde F
: A method for efficiently purifying methacrylate obtained by catalytic oxidation with a molecular oxygen-containing gas in the presence of water vapor using a combination of semi-permeable membrane treatment with MIFr and extraction with isopropyl acetate.

〔従来の技術と発明が解決すべき問題点〕イソブチレン
、第3級ブタノール、メタクロレインまたはイソブチル
アルデヒド(以下これらを単に原料と呼ぶ)を1段また
は2段の反応で気相接触酸化して得られるメタクリル酸
は、抽出および蒸留などの通常の精製手段で高純度の製
品とすることができる。
[Prior art and problems to be solved by the invention] Isobutylene, tertiary butanol, methacrolein, or isobutyraldehyde (hereinafter referred to simply as raw materials) are obtained by gas phase catalytic oxidation in one or two stages of reaction. The methacrylic acid obtained can be made into a highly pure product by conventional purification means such as extraction and distillation.

しかしながら、工業的にこれらを実施するに当っては操
業性および経済性の面で多くの問題点を抱えでいる。即
ち、上記原料からメタクリル酸を製造する場合、酸化反
応生成ガス中には、メタクリル酸以外にメタクロレイン
、M素、炭酸ガス、−酸化炭素、水蒸気をはじめ未反応
の04炭化水素類、酸素、更には副生成物のアルデヒド
類、ケトン類、有機酸類及び重合体等が含まれでいる。
However, when implementing these methods industrially, there are many problems in terms of operability and economy. That is, when producing methacrylic acid from the above raw materials, the oxidation reaction product gas contains, in addition to methacrylic acid, methacrolein, carbon dioxide, carbon dioxide, unreacted 04 hydrocarbons including water vapor, oxygen, Furthermore, by-products such as aldehydes, ketones, organic acids, and polymers are included.

この酸化反応生成ガスは水で冷却して、メタクリル亀の
水溶液となし、次いで有機溶媒を用いて、メタクリル酸
を抽出し、抽出物から有機溶媒を除去回収してメタクリ
ル酸を得ることが一般的であり、この方法に関しては既
に多くの文献がある。
This oxidation reaction product gas is generally cooled with water to form an aqueous solution of methacrylic acid, then methacrylic acid is extracted using an organic solvent, and the organic solvent is removed and recovered from the extract to obtain methacrylic acid. There are already many documents regarding this method.

これらの方法は多くの場合、主生成物であるメタクリル
酸を選択的に抽出することを主目的としているが、主副
生成物である酢酸をも同時に抽出し、酢酸は分離回収後
、前工程でメタクロレインの捕集溶媒として使用する方
法も提案されている(特開昭59−93028) 。
In many cases, the main purpose of these methods is to selectively extract the main product, methacrylic acid, but the main by-product, acetic acid, is also extracted at the same time. A method of using it as a collection solvent for methacrolein has also been proposed (Japanese Patent Application Laid-open No. 59-93028).

気相空気酸化によるメタクリル酸製造時に副生する酢酸
はメタクリル酸に対し10〜30%程度にも達するので
これを回収する提案も種々なされでいる。このように、
酢酸をメタクリル酸と同時に抽出する後者の提案は設備
的にも、熱量的にも経済的な方法といえる0、 前記メタクリル酸水溶液を得る際に、メタクリル酸、水
と共に上記の多くの副生物も凝縮捕集される。このうち
比較的軽沸点の物質は蒸留操作等で簡単に除去すること
ができ、またテレフタル酸等の高沸点で溶解度の低い芳
香族カルボン酸は大部分個体として析出しているので適
当な手段でか別除去することができる。ところが、これ
ら芳香族カルボン酸の残分の他、マレイン酸、シトラコ
ン酸、およびメタクロレインとメタクリル酸の重合体等
(以下これらを不揮発残分と呼ぶ)がメタクリル酸水溶
液中に溶存しておりメタクリル酸の液々抽出時に液々界
面におけるスカムの発生、抽出塔内のクール状物質によ
る汚染および閉塞、および/または抽残相側でのカーボ
ン状物質の析出および配管の閉塞となって現れ、連続運
転に支障を来たしている。
Since acetic acid by-produced during the production of methacrylic acid by gas-phase air oxidation amounts to about 10 to 30% of the methacrylic acid, various proposals have been made to recover this acetic acid. in this way,
The latter proposal, in which acetic acid is extracted at the same time as methacrylic acid, is an economical method both in terms of equipment and calorific value.When obtaining the methacrylic acid aqueous solution, many of the above-mentioned by-products are also extracted together with methacrylic acid and water. Condensed and collected. Among these, substances with relatively low boiling points can be easily removed by distillation, etc., and aromatic carboxylic acids with high boiling points and low solubility, such as terephthalic acid, are mostly precipitated as solids, so they can be removed by appropriate means. Can be removed separately. However, in addition to these aromatic carboxylic acid residues, maleic acid, citraconic acid, and polymers of methacrolein and methacrylic acid (hereinafter referred to as nonvolatile residues) are dissolved in the methacrylic acid aqueous solution, and methacrylic acid During liquid-liquid extraction of acid, this appears as scum at the liquid-liquid interface, contamination and blockage by cool substances in the extraction tower, and/or precipitation of carbon-like substances on the raffinate phase side and blockage of piping. My driving is impaired.

特にメタクリル酸と酢酸とを同時に析出する溶媒、例え
ば酢酸イソプロピルを用いた場合について、本発明者ら
が検討したところでは、溶媒の抽出力が強いため、メタ
クリル酸と酢酸のみならず、前記不揮発残分の50〜6
0%をも抽出し、それがために液々界面においで大量の
スカムが発生するばかりでなく、次の溶剤回収工程にお
いで、蒸留塔のりボイラー及び塔底部に重合物の生成及
び閉塞を生ずることが知見された。
In particular, when using a solvent that precipitates methacrylic acid and acetic acid at the same time, such as isopropyl acetate, the present inventors found that due to the strong extraction power of the solvent, not only methacrylic acid and acetic acid but also the non-volatile residue is used. 50-6 minutes
0% is extracted, which not only generates a large amount of scum at the liquid-liquid interface, but also causes polymer formation and blockage in the distillation column boiler and column bottom in the next solvent recovery step. It was discovered that

かかる問題点を解消する方法としては、原因物質と考え
られる不揮発残分の発生を防止または抑制するか、ある
いは対症療法的に、発生した不揮発残分を除去する方法
が考えられる。前者の提案としては、例えば、特公昭4
8−10452、特開昭48−26717、特開昭49
−104884、特開昭49−54317などがあるが
、特開昭52−48609号公報明細書にも記載されて
いるように、不揮発残分の発生を完全に抑制することは
事実上不可能である。
Possible methods for solving this problem include preventing or suppressing the generation of non-volatile residues that are thought to be the causative agent, or removing generated non-volatile residues as a symptomatic treatment. As for the former proposal, for example,
8-10452, JP-A-48-26717, JP-A-49
-104884, JP-A-49-54317, etc. However, as stated in the specification of JP-A-52-48609, it is virtually impossible to completely suppress the generation of non-volatile residues. be.

一方、後者の提案としては(1)抽出前にメタクリル酸
水溶液を活性炭や特殊なイオン交換樹脂で処理する方法
(特開昭5O−52021) 、(2)抽出操作により
メタクリル酸が抽出されるに伴い抽残相(水相)中に不
揮発残分が析出するのを防止するために水相への溶解/
Iを上げる目的で予め添加物を加えて水溶性付加物とし
ておく方法。(特開昭50−151805、同58−1
28337、同58−99434、同59−44337
、同59−44338) 、(3)抽出前に強制的にス
カムを発生させ炉別する方法(特開昭54−68617
、同56−16438、同56−79634) 、(4
)メタクリル酸水溶液とする前に熱水で反応生成ガス中
から選択的に溶解除去する方法(特開昭52−4860
9)などがある。
On the other hand, the latter proposals include (1) a method of treating an aqueous methacrylic acid solution with activated carbon or a special ion exchange resin before extraction (Japanese Patent Application Laid-Open No. 50-52021), and (2) a method in which methacrylic acid is extracted by the extraction operation. In order to prevent non-volatile residue from precipitating in the raffinate phase (aqueous phase),
A method in which additives are added in advance to form a water-soluble adduct for the purpose of increasing I. (Unexamined Japanese Patent Publication No. 50-151805, No. 58-1
28337, 58-99434, 59-44337
, 59-44338), (3) A method for forcibly generating scum and separating it in a furnace before extraction (Japanese Patent Laid-Open No. 54-68617)
, 56-16438, 56-79634) , (4
) A method of selectively dissolving and removing the reaction product gas with hot water before making it into an aqueous solution of methacrylic acid (JP-A-52-4860)
9) etc.

しかしく1)の方法はプロセスを複雑にし、かつ長時間
の運転で種々のトラブルを発生し、装置の洗滌などのた
め多ぐの廃水を発生し工業的には採用し難い、〔2〕の
方法は操作を簡略化するが酸性度の大きい芳香族カルボ
ン酸等をアルカリ変性できたとしても多くの重合体を充
分に変性することは難しく、そのために上記問題点を根
本的に解決できないこと、また本発明者らの検討では、
アルカリ変性されたものが一部有機相に同伴されて析出
し、そこで配管閉塞を起こすという新たな問題を生じる
等、まだ工業的には難点がある。(3)の方法は全量の
スカムを発生させてしまうにはメタクリル#iを充分に
抽出してしまう必要があるにも拘らず、溶剤を1段で混
ぜるだけなのでその効果は小ざ〈満足できる処理ではな
く、操作も繁雑である。 (4)4の方法は反応生成ガ
スを急冷する前の処理であるから、急冷時に新たに生ず
る重合体に対しては除去手段がない。本発明者らの検討
では重合体は反応過程でできるものと、その後の急冷工
程でできるものと、はぼ半々位であることを付き止めて
いる。したがって長期間の抽出操作を行うには根本的な
対策とはなり得ない。
However, method 1) complicates the process, causes various troubles during long-time operation, and generates a lot of waste water for cleaning the equipment, so it is difficult to adopt method 2 industrially. Although the method simplifies the operation, even if highly acidic aromatic carboxylic acids etc. can be modified with alkali, it is difficult to sufficiently modify many polymers, and therefore the above problems cannot be fundamentally solved; In addition, in the study of the present inventors,
There are still some difficulties in industrial use, such as a new problem of alkali-modified substances being partially entrained in the organic phase and precipitated, which causes pipe blockage. Although method (3) requires sufficient extraction of methacrylic #i to generate the entire amount of scum, the effect is only small (satisfactory) because the solvent is mixed in one step. Not only the processing but also the operation is complicated. (4) Since method 4 is a treatment before quenching the reaction product gas, there is no means for removing the polymer newly generated during quenching. The present inventors have determined that the amount of polymer produced during the reaction process and that produced during the subsequent quenching process are about 50/50. Therefore, it cannot be a fundamental countermeasure for long-term extraction operations.

〔問題点を解決するための手段〕[Means for solving problems]

本発明者らは、この点に着目し、メタクリル酸の精製方
法につい!鋭意検討を重ねた結果、上記メタクリル酸水
溶液をポリスルホン、ポリアクリロニトリル又はポリア
ミドからなる半透膜に加圧下に接触させて膜処理するこ
とにより、大きい透過率にで、且つ80%以上の排除率
亡不揮発残分が除去された透過液を得、これを液々抽出
すると、前述の如き抽出塔内での汚染および閉塞が皆無
になること、また抽剤である酢酸イソプロピルの回収に
おいても蒸留塔での重合物や生成や閉塞が生じなくなる
ことを見い出し本発明を完成した。
The present inventors focused on this point and developed a method for purifying methacrylic acid! As a result of extensive studies, we have found that by bringing the above methacrylic acid aqueous solution into contact with a semipermeable membrane made of polysulfone, polyacrylonitrile, or polyamide under pressure for membrane treatment, we can achieve a high permeability and eliminate an exclusion rate of 80% or more. Obtaining a permeate from which non-volatile residues have been removed and extracting it liquid-liquid eliminates contamination and clogging in the extraction column as described above, and also allows for recovery of isopropyl acetate, which is the extraction agent, in the distillation column. The present invention has been completed based on the discovery that polymerization, formation, and blockage of polyurethane particles do not occur.

即ち、本発明のメタクリル酸の精製法はイソブチレン、
第3級ブタノール、メタクロレインもしくはイソブチル
アルデヒドを水蒸気の存在下に分子状酸素含有ガスによ
り接触酸化し、接触酸化からの酢Mを主たる不純物とす
る反応生成ガスを冷却して得られるメタクリル酸水溶液
を半透膜に加圧下に接触させ、半透膜透過液から酢酸イ
ソプロピルを抽剤として、メタクリル酸と酢酸とを同時
に抽出す☆ことを特徴とするものである。
That is, the method for purifying methacrylic acid of the present invention uses isobutylene,
A methacrylic acid aqueous solution obtained by catalytically oxidizing tertiary butanol, methacrolein or isobutyraldehyde with a molecular oxygen-containing gas in the presence of water vapor and cooling the reaction product gas containing vinegar M as the main impurity from the catalytic oxidation. This method is characterized in that methacrylic acid and acetic acid are simultaneously extracted by contacting a semipermeable membrane under pressure and using isopropyl acetate as an extraction agent from the semipermeable membrane permeate.

本発明におけるメタクリル酸水溶液は、前記原料を水蒸
気の存在下に分子状酸素含有ガスにより、1段又は2段
で接触酸化して得られるものであるが、酸化生成物を冷
却凝縮捕集したメタクリル酸を含む水溶液あるいは該水
溶液からストリッピング等で軽沸点成分であるアセトン
、およびメタクロレイン等のケトン類およびアルデヒド
類を除去した債のメタクリル酸水溶液の形で使用される
。しかし半透膜の寿命等を考慮すると軽沸点成分を除去
したメタクリル酸水溶液が望ましい。
The aqueous methacrylic acid solution in the present invention is obtained by catalytically oxidizing the raw material in one or two stages with a molecular oxygen-containing gas in the presence of water vapor, and the methacrylic acid aqueous solution is obtained by catalytically oxidizing the raw material in one or two stages with a molecular oxygen-containing gas in the presence of water vapor. It is used in the form of an aqueous solution containing an acid or an aqueous methacrylic acid solution obtained by removing low-boiling components such as acetone, ketones such as methacrolein, and aldehydes from the aqueous solution by stripping or the like. However, in consideration of the life span of the semipermeable membrane, an aqueous methacrylic acid solution from which low-boiling components have been removed is desirable.

本発明においてメタクリル酸水溶液を処理するのに用い
る半透膜は、分画分子量が好ましくは500〜2,00
0のものである。そして、この半透膜はポリスルホン、
ポリアクリロニトリル、ポリアミドからなるものが好ま
しい、・・ 本発明においては、メタクリル酸水溶液は一般的には5
〜50°Cで半透膜に加圧下に接触される。
The semipermeable membrane used to treat the methacrylic acid aqueous solution in the present invention preferably has a molecular weight cut-off of 500 to 2,000.
0. This semipermeable membrane is made of polysulfone,
Preferably, those made of polyacrylonitrile or polyamide... In the present invention, the methacrylic acid aqueous solution is generally
The semipermeable membrane is contacted under pressure at ~50°C.

一般に処理温度が高い程、大きい透過液量を得ることが
できるか、メタクリル酸水溶液の安定性の面、また続く
酢酸インプロピルによる抽出処理温度も考慮すると50
℃よりも高い温度は好ましくない、また、5℃より低い
温度では透過液量が実用上からは小さく、また抽出処理
温度としても抽出効率が低下することから好ましくない
In general, the higher the treatment temperature, the larger the amount of permeate can be obtained. Considering the stability of the methacrylic acid aqueous solution and the temperature of the subsequent extraction treatment with inpropyl acetate,
Temperatures higher than 5° C. are not preferred, and temperatures lower than 5° C. are not preferred because the amount of permeate is small from a practical standpoint, and the extraction efficiency is also lowered as an extraction treatment temperature.

膜処理における圧力は、用いる半透膜の形態によって2
0〜60にq/cm (ゲージ圧、以下向し)とされる
、圧力が小さすぎると液の透過速度が小さく、一方圧力
が大きすぎると膜が容易に圧密化したり、又損傷する恐
れがあるので好ましくない。
The pressure in membrane treatment varies depending on the form of the semipermeable membrane used.
0 to 60 q/cm (gauge pressure, below); if the pressure is too low, the liquid permeation rate will be low, while if the pressure is too high, the membrane may be easily consolidated or damaged. I don't like it because it is.

更に本発明においでは、上記のような条件下で膜透過液
としてメタクリル酸水溶液の少なくとも50%以上、好
ましくは70〜98%が回収されるまで、メタクリル酸
水溶液を半透膜に連続して循環させつつ、加圧接触させ
るのが望ましい、必要ならば、水を適宜に加えで透過し
た分を補う、膜面に対する流速は膜面に平行の線速を0
.5〜8m/sec 、好ましくは1〜4m/secと
するのがよい。
Furthermore, in the present invention, the methacrylic acid aqueous solution is continuously circulated through the semipermeable membrane under the above conditions until at least 50% or more, preferably 70 to 98%, of the methacrylic acid aqueous solution is recovered as the membrane permeate. It is desirable to pressurize the contact while keeping the water flowing.If necessary, add water appropriately to compensate for the permeation.The flow velocity with respect to the membrane surface is set to 0.
.. The speed is preferably 5 to 8 m/sec, preferably 1 to 4 m/sec.

線速か小さすぎると膜面での不透過成分の濃度分極が大
きくなって、メタクリル酸の透過を妨げ、また、大きす
ぎるときは、徒らにポンプの動力費が嵩むので好ましく
ない。
If the linear velocity is too low, the concentration polarization of impermeable components on the membrane surface becomes large, which impedes the permeation of methacrylic acid, and if it is too high, the power cost of the pump increases undesirably.

かくして不揮発残分の大部分が除去されたメタクリル酸
水溶液は溶媒による抽出工程および溶媒の回収蒸留工程
における前述の如き問題を生ずる心配がないので、目的
成分であるメタクリル酸および酢酸に対して選択性の高
い抽出溶媒である酢酸イソプロピルをはじめで使用する
ことができる。
In this way, the methacrylic acid aqueous solution from which most of the non-volatile residue has been removed is free from the above-mentioned problems in the solvent extraction process and the solvent recovery distillation process, so it is selective to the target components methacrylic acid and acetic acid. Isopropyl acetate, which is a high extraction solvent, can be used initially.

酢酸イソプロピルの抽出溶媒としての利点は特開昭59
−93028号公報明細書にも記載されでいるが、メタ
クリル酸を99%以上抽出する条件で酢酸をも70%以
上抽出することができる。
The advantages of isopropyl acetate as an extraction solvent are described in JP-A-59
As described in the specification of Japanese Patent No. 93028, under the conditions that extract 99% or more of methacrylic acid, 70% or more of acetic acid can also be extracted.

酢酸イソプロピルは酢酸濃度5%の水溶液の分配係数が
0.7と大きい割に水への溶解度が小さい(2,9%、
20℃)ので抽残水からの回収費用が少なくですむ6ま
た、沸点が89℃であって、酢酸の沸点との差が大きく
、且つ共沸を作らないので溶剤の分離が容易である。
Isopropyl acetate has a large partition coefficient of 0.7 in an aqueous solution with an acetic acid concentration of 5%, but its solubility in water is low (2.9%,
20°C), so the cost of recovering from the raffinate water is low6.Also, the boiling point is 89°C, which is a large difference from the boiling point of acetic acid, and since it does not create an azeotrope, it is easy to separate the solvent.

同じ酢酸エステルでも酢酸エチルは水への溶解度が大き
く、又水、にょうで加水分解され易く好ましくない、又
酢酸ノルマルプロピルは酢酸イソプロピルより沸点が高
く、酢酸の沸点に近づくので好ましくない、酢酸ノルマ
ルブチル、酢酸イソブチルはいずれも沸点が酢酸に近接
しており、酢酸との分離が困難である。
Among the same acetic esters, ethyl acetate has a high solubility in water and is easily hydrolyzed by water and odour, making it undesirable.Also, n-propyl acetate has a higher boiling point than isopropyl acetate, approaching the boiling point of acetic acid, which is undesirable. Both butyl and isobutyl acetate have boiling points close to acetic acid, making it difficult to separate them from acetic acid.

〔実施例〕〔Example〕

次に実施例によって本発明を説明する。 Next, the present invention will be explained by examples.

実施例1 ヘテロポリ酸系の酸化触媒を用い、メタクロレインを突
気および水蒸気の存在下に気相接触酸化して得られた反
応生成ガスを、間接冷却器で250℃に冷却した後、急
冷塔へ導入した。
Example 1 Using a heteropolyacid-based oxidation catalyst, methacrolein was catalytically oxidized in the vapor phase in the presence of sudden air and water vapor. The reaction product gas was cooled to 250°C in an indirect cooler, and then transferred to a quenching tower. introduced into.

急冷塔は塔径6インチ、高さ3mでラシヒリングを2m
充填したもので、塔内で凝縮した酸化反応生成物の一部
を冷却器で冷却した後塔頂部へ循環し、反応生成ガスと
並流接触させで、目的物であるメタクリル酸の凝縮捕集
を行った。得られたメタクリル酸の水溶液はメタクリル
酸21.0部、高分子物質3.7部、アルデヒド0.5
部、有機酸類6.0部、残り水であった。このメタクリ
ル酸水溶液を40℃で膜面積0.2rrf、分画分子量
500のポリアミド膜の平板モジュールに101/Hr
で供給し、操作圧力40にq/cポで処理を行った。透
過液量は6511tri時で透過液中の組成はメタクリ
ル酸19.2部、高分子量物質0.05部、アルデヒド
類0.5部、有機酸類5.0部であった。得られた水溶
液をメタクリル酸抽出塔(塔径75mm、円板数70枚
の回転円板場)の上部へ2.8に9/Hrの速度で供給
した。塔底より酢酸インプロピルを2.2Kq/Hrで
供給しメタクリル酸の抽出を行った。
The quenching tower has a tower diameter of 6 inches, a height of 3 m, and a Raschig ring of 2 m.
A part of the oxidation reaction product condensed in the tower is cooled by a cooler and then circulated to the top of the tower, where it is brought into parallel flow contact with the reaction product gas, and the target product, methacrylic acid, is condensed and collected. I did it. The obtained aqueous solution of methacrylic acid contained 21.0 parts of methacrylic acid, 3.7 parts of a polymeric substance, and 0.5 parts of an aldehyde.
1 part, 6.0 parts of organic acids, and the remainder water. This methacrylic acid aqueous solution was applied to a polyamide membrane flat module with a membrane area of 0.2rrf and a molecular weight cutoff of 500 at 40°C for 101/Hr.
The treatment was carried out at an operating pressure of 40 q/c. The amount of permeated liquid was 6511 tri, and the composition of the permeated liquid was 19.2 parts of methacrylic acid, 0.05 parts of high molecular weight substances, 0.5 parts of aldehydes, and 5.0 parts of organic acids. The obtained aqueous solution was supplied to the upper part of a methacrylic acid extraction column (column diameter: 75 mm, rotating disk field with 70 disks) at a rate of 2.8 to 9/Hr. Inpropyl acetate was supplied from the bottom of the column at 2.2 Kq/Hr to extract methacrylic acid.

各酸類の抽出はメタクリルM99.9%、アクリル酸9
2.0%、酢酸75.1%であった。このメタクリル酸
抽出液は3.0にq/Hrの供給速度で溶剤回収塔(塔
径70mm、段数30段の多孔板塔)に送入した。
Extraction of each acid was methacrylic M99.9%, acrylic acid M99.9%,
2.0% and acetic acid 75.1%. This methacrylic acid extract was fed into a solvent recovery column (a perforated plate column with a column diameter of 70 mm and 30 plates) at a supply rate of 3.0 q/Hr.

塔頂からは酢酸イソプロピルと水を回収し、デカンタ−
で水層を分離した後、抽出塔ヘリサイクルした。塔底か
らは大部分の酢酸イソプロピルと水を除去し終えた液を
得た。この液から順次酢酸分離塔、メタクリル酸精製塔
を経て塔頂から精製メタクリル酸を得ることができた。
Isopropyl acetate and water are recovered from the top of the tower and placed in a decanter.
After separating the aqueous layer, it was recycled to an extraction column. A liquid from which most of the isopropyl acetate and water had been removed was obtained from the bottom of the column. This liquid was passed sequentially through an acetic acid separation column and a methacrylic acid purification column, and purified methacrylic acid could be obtained from the top of the column.

この間抽出塔界面におけるスカムの発生はもとよりター
ル状物による詰り現象もなく、また溶剤回収塔の塔底に
おける液の重合はもとより白濁もなく安定な運転をする
ことができた。
During this period, there was no occurrence of scum or clogging due to tar-like substances at the interface of the extraction tower, and stable operation was possible without any clouding or polymerization of the liquid at the bottom of the solvent recovery tower.

比較例1 実施例1と同じメタクリル酸の水溶液を半透膜による処
理をすることなく、酢酸イソプロピルを溶媒として、実
施例1と同じ条件でメタクリル酸の抽出を行った。運転
開始後間もなく界面に多量のスカムが発生して界面の判
別が困難となフできたので界面付近のノズルから液と共
にスカムを抜き出しながら運転を継続した。抽出液側の
色は褐色を呈し、組成的1こはメタクリル酸21.3部
、アルデヒド類0.2部、高分子物質1.9部、有機酸
類5.0部、水7.6部、残り溶媒であった。この抽出
液を溶剤回収塔に送入して蒸留したところ、運転開始1
時間後に塔底部が白濁し、10時間後にはりボイラース
チームの圧力が上昇し、塔底液の抜き出しも不良となっ
たので運転を停止し、内+!i13を点検したところ粘
調なポリマーがりボイラー上部、塔下部目皿部に可成り
付着していた。
Comparative Example 1 Methacrylic acid was extracted from the same aqueous solution of methacrylic acid as in Example 1 under the same conditions as in Example 1 using isopropyl acetate as a solvent without treating it with a semipermeable membrane. Shortly after the start of operation, a large amount of scum was generated at the interface, making it difficult to identify the interface, so operation was continued while extracting the scum along with the liquid from the nozzle near the interface. The color of the extract is brown, and the composition is 21.3 parts of methacrylic acid, 0.2 parts of aldehydes, 1.9 parts of polymeric substances, 5.0 parts of organic acids, 7.6 parts of water, The remainder was solvent. When this extract was sent to a solvent recovery tower and distilled,
After an hour, the bottom of the tower became cloudy, and 10 hours later, the pressure of the boiler steam rose and the bottom liquid was not being extracted properly, so the operation was stopped and the inside +! When I13 was inspected, it was found that a considerable amount of viscous polymer had adhered to the upper part of the boiler and the perforated plate in the lower part of the column.

〔発明の効果〕〔Effect of the invention〕

本発明によれば、酢酸を主たる不純物として含有するメ
タクリル酸溶液から半透膜処理によって不揮発残分を除
去したのちメタクリル酸と酢酸とを抽出するので、メタ
クリル酸に対して選択性が高いが、不揮発残分の50〜
60%をも抽出する酢酸イソブビルを抽剤として用いる
ことができる。この結果、抽出、油剤の回収、抽剤と酢
酸との分別が容易となり、装置的にも回収エネルギーの
面でも極めて倚利となフた。また、抽出工程においで析
出するカーボン状物および/またはタール状物や液々界
面に浮遊するスカムの発生が実雲上認められなくなり、
長期間操業を続ける上で大きな障害となっていた問題が
なくなった。
According to the present invention, methacrylic acid and acetic acid are extracted after removing nonvolatile residues from a methacrylic acid solution containing acetic acid as the main impurity by semipermeable membrane treatment, so that the selectivity for methacrylic acid is high; Non-volatile residue 50~
Isobuvir acetate, which extracts up to 60%, can be used as an extractant. As a result, extraction, recovery of the oil agent, and separation of the extractant and acetic acid are facilitated, making it extremely efficient in terms of equipment and recovery energy. In addition, the occurrence of carbon-like substances and/or tar-like substances that precipitate during the extraction process and scum floating on the liquid-liquid interface is no longer observed,
The problems that had been a major hindrance to continued operation over a long period of time have been eliminated.

Claims (1)

【特許請求の範囲】[Claims] イソブチレン、第3級ブタノール、メタクロレインもし
くはイソブチルアルデヒドを水蒸気の存在下に分子状酸
素含有ガスにより接触酸化し、接触酸化からの、酢酸を
主たる不純物とする反応生成ガスを冷却して得られるメ
タクリル酸水溶液を半透膜に加圧下に接触させ、半透膜
透過液から酢酸イソプロピルを抽剤として、メタクリル
酸と酢酸とを同時に抽出することを特徴とするメタクリ
ル酸の精製法。
Methacrylic acid obtained by catalytically oxidizing isobutylene, tertiary butanol, methacrolein, or isobutyraldehyde with a molecular oxygen-containing gas in the presence of water vapor, and cooling the reaction product gas containing acetic acid as the main impurity from the catalytic oxidation. A method for purifying methacrylic acid, which comprises bringing an aqueous solution into contact with a semipermeable membrane under pressure, and simultaneously extracting methacrylic acid and acetic acid from the semipermeable membrane permeate using isopropyl acetate as an extractant.
JP60258721A 1985-11-20 1985-11-20 Method for purifying methacrylic acid Expired - Fee Related JPH0694433B2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP60258721A JPH0694433B2 (en) 1985-11-20 1985-11-20 Method for purifying methacrylic acid

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP60258721A JPH0694433B2 (en) 1985-11-20 1985-11-20 Method for purifying methacrylic acid

Publications (2)

Publication Number Publication Date
JPS62120341A true JPS62120341A (en) 1987-06-01
JPH0694433B2 JPH0694433B2 (en) 1994-11-24

Family

ID=17324167

Family Applications (1)

Application Number Title Priority Date Filing Date
JP60258721A Expired - Fee Related JPH0694433B2 (en) 1985-11-20 1985-11-20 Method for purifying methacrylic acid

Country Status (1)

Country Link
JP (1) JPH0694433B2 (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6888026B2 (en) * 2001-09-28 2005-05-03 Nippon Shokubai Co., Ltd. Method for producing (meth)acrylic acid
WO2007074827A1 (en) * 2005-12-26 2007-07-05 Mitsubishi Rayon Co., Ltd. Method for extracting methacrylic acid
WO2010090100A1 (en) * 2009-02-03 2010-08-12 株式会社日本触媒 Method for regenerating filter

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS53101303A (en) * 1977-02-15 1978-09-04 Kanegafuchi Chem Ind Co Ltd Separation of organic substances having carboxyl group
JPS5899434A (en) * 1981-12-10 1983-06-13 Nippon Shokubai Kagaku Kogyo Co Ltd Purification of methacrylic acid
JPS5993028A (en) * 1982-11-19 1984-05-29 Nippon Kayaku Co Ltd Recovery of methacrylic acid
JPS60104034A (en) * 1983-11-11 1985-06-08 Nippon Kayaku Co Ltd Recovery of methacrylic acid

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS53101303A (en) * 1977-02-15 1978-09-04 Kanegafuchi Chem Ind Co Ltd Separation of organic substances having carboxyl group
JPS5899434A (en) * 1981-12-10 1983-06-13 Nippon Shokubai Kagaku Kogyo Co Ltd Purification of methacrylic acid
JPS5993028A (en) * 1982-11-19 1984-05-29 Nippon Kayaku Co Ltd Recovery of methacrylic acid
JPS60104034A (en) * 1983-11-11 1985-06-08 Nippon Kayaku Co Ltd Recovery of methacrylic acid

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6888026B2 (en) * 2001-09-28 2005-05-03 Nippon Shokubai Co., Ltd. Method for producing (meth)acrylic acid
WO2007074827A1 (en) * 2005-12-26 2007-07-05 Mitsubishi Rayon Co., Ltd. Method for extracting methacrylic acid
EA013757B1 (en) * 2005-12-26 2010-06-30 Мицубиси Рэйон Ко., Лтд. Method for extracting methacrylic acid
US7897814B2 (en) 2005-12-26 2011-03-01 Mitsubishi Rayon Co., Ltd. Method for extracting methacrylic acid
JP4995715B2 (en) * 2005-12-26 2012-08-08 三菱レイヨン株式会社 Extraction method of methacrylic acid
WO2010090100A1 (en) * 2009-02-03 2010-08-12 株式会社日本触媒 Method for regenerating filter
JP5461442B2 (en) * 2009-02-03 2014-04-02 株式会社日本触媒 How to play the filter
US8734655B2 (en) 2009-02-03 2014-05-27 Nippon Shokubai Co., Ltd. Method for regenerating filter

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