JP3871406B2 - Method for purifying methacrylic acid - Google Patents
Method for purifying methacrylic acid Download PDFInfo
- Publication number
- JP3871406B2 JP3871406B2 JP21611997A JP21611997A JP3871406B2 JP 3871406 B2 JP3871406 B2 JP 3871406B2 JP 21611997 A JP21611997 A JP 21611997A JP 21611997 A JP21611997 A JP 21611997A JP 3871406 B2 JP3871406 B2 JP 3871406B2
- Authority
- JP
- Japan
- Prior art keywords
- methacrylic acid
- treatment
- exchange resin
- formaldehyde
- cation exchange
- 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.)
- Expired - Lifetime
Links
Landscapes
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Description
【０００１】
【発明の属する技術分野】
本発明は、イソブチレン、第３級ブチルアルコールおよびメチル第３級ブチルエーテルからなる群から選ばれる少なくとも一種の化合物、または、イソブタン、メタクロレイン、イソブチルアルデヒドおよびイソ酪酸からなる群から選ばれる一種の化合物（以下、炭素数４の化合物とも言う）の気相接触酸化反応で得られたメタクリル酸含有物を精製する方法に関する。
【０００２】
【従来の技術】
イソブタン、イソブチレン、第３級ブチルアルコール、メチル第３級ブチルエーテル、メタクロレイン、イソブチルアルデヒド、イソ酪酸等の気相接触酸化反応で得られるメタクリル酸含有物は抽出、蒸留等の通常の精製手段により不純物の少ない製品とすることができるが、微量に存在する不純物を完全に除去することは困難であり、そのため製品の着色を完全に防止できなかったり、得られた製品の重合性が著しく劣るなどの問題が生じている。
【０００３】
このような微量不純物の中には、抽出剤との溶解性および沸点がメタクリル酸と近いものがあり、通常の抽出および蒸留等の物理的手段による精製法だけでは除去することが極めて困難である。蒸留塔の段数を増やす等の手法により微量不純物をいくらか低減することは可能であるが、このような方法は工程が複雑化してコスト高を招くため、工業的に採用することはほとんど不可能である。
【０００４】
そこで、スルホン酸基含有化合物およびホルムアルデヒド含有物よる処理とアミン類による処理を組み合わせる方法（特公平３−３６４５号公報）、スルホン酸基含有化合物による処理とアミン類による処理を組み合わせる方法（特公平３−３６４６号公報）等が報告されている。
【０００５】
しかしながら、これらの方法により、着色が少なく重合性能の優れたメタクリル酸を得ようとすると、前者の方法は多量の処理剤が必要であり、後者の方法は多量に使用するアミン類とメタクリル酸が反応してメタクリル酸の回収率が低下するため、何れも経済性が悪いという問題があった。
【０００６】
【発明が解決しようとする課題】
本発明の課題は、着色が少なく重合性能の優れたメタクリル酸を少量の処理剤で得ることができるメタクリル酸の精製方法を提供することである。
【０００７】
【課題を解決するための手段】
本発明は、炭素数４の化合物の気相接触酸化反応で得られたメタクリル酸含有物を蒸留により精製する方法において、あらかじめメタクリル酸含有物を第１級および／または第２級のアミノ基含有化合物により処理し、強酸性陽イオン交換樹脂により処理した後、ホルムアルデヒド含有物を添加して強酸性陽イオン交換樹脂を充填した固定床に流通させて処理したものを蒸留することを特徴とするメタクリル酸の精製方法にある。
【０００８】
【発明の実施の形態】
本発明の精製対象であるメタクリル酸含有物は、イソブチレン、第３級ブチルアルコールおよびメチル第３級ブチルエーテルからなる群から選ばれる少なくとも一種の化合物、または、イソブタン、メタクロレイン、イソブチルアルデヒドおよびイソ酪酸からなる群から選ばれる一種の化合物を気相接触酸化して得られるものである。なお、メチル第３級ブチルエーテルは、気相接触酸化の際に直ちに分解してイソブチレンおよび／または第３級ブチルアルコールが得られる。
【０００９】
炭素数４の化合物を気相接触酸化して得られるメタクリル酸含有物としては、例えば、メタクロレインを気相接触酸化して得られるメタクリル酸水溶液に対して抽出および蒸留等の分離精製を行い、メタクリル酸の含有率を約５０重量％以上に濃縮したものが挙げられるが、これに制限されるものではない。
【００１０】
炭素数４の化合物を気相接触酸化して得られるメタクリル酸含有物は、最初に第１級および／または第２級のアミノ基含有化合物により処理される。以下、この工程をアミン類処理という。
【００１１】
アミン類処理で用いられる第１級または第２級のアミノ基含有化合物としては、脂肪族および芳香族アミンのいずれでもよく、１分子中に複数個のアミノ基を有するアミン類、アンモニア、ヒドラジンおよびその誘導体、さらにはヒドロキシルアミンおよびその無機酸塩等の化合物もこれに含まれる。このような第１級または第２級のアミノ基含有化合物としては、例えば、プロピルアミン、ブチルアミン、ペンチルアミン、ヘキシルアミン、ジエチルアミン、ジ−ｎ−プロピルアミン、ジイソプロピルアミン、メチルエチルアミン、エチレンジアミン、トリメチレンジアミン、テトラメチレンジアミン、ペンタメチレンジアミン、Ｎ，Ｎ’−ジフェニルエチレンジアミン、エタノールアミン、ヘキサメチレンジアミン、ジエチレントリアミン、テトラエチレンペンタミン、アニリン、トルイジン、Ｎ−エチルアニリン、Ｎ−プロピルアミン、ジフェニルアミン、フェニレンジアミン、Ｎ−メチルフェニレンジアミン、ベンジルアミン、フェネチルアミン、アニシジン等が挙げられる。
【００１２】
第１級および／または第２級のアミノ基含有化合物は、単独で用いてもよいが、２種類以上の化合物を適宜組み合わせて用いてもよい。また、第１級および／または第２級のアミノ基含有化合物の添加量は、メタクリル酸含有物１００重量部に対して、０．００１〜１重量部、特に０．００５〜０．８重量部の範囲が好ましい。
【００１３】
アミン類処理は通常熱処理を必要とし、５０〜１５０℃、特に８０〜１３０℃の温度で熱処理を行うことが好ましい。このときの処理時間は５分〜５時間、特に１５分〜３時間の範囲が好ましい。アミン類処理の方法としては、例えば、メタクリル酸含有物に第１級および／または第２級のアミノ基含有化合物を添加して、所定の温度に加熱した後、好ましくは混合物を撹拌しながら一定時間保持する方法が挙げられるがこれに限定されるものではない。
【００１４】
アミン類処理を行った液は、そのまま次の処理を行ってもよいが、蒸留した後に次の処理を行った方が好ましい結果が得られる。
【００１５】
アミン類処理を行った液は、次に強酸性陽イオン交換樹脂により処理される。以下、この工程をイオン交換樹脂処理という。ここで強酸性陽イオン交換樹脂としては、通常スルホン酸基を有するものが用いられ、そのイオン交換容量および架橋度などに関して特に制限はない。イオン交換樹脂処理の方式は回分式および連続式のいずれでもよいが、工業的には強酸性陽イオン交換樹脂を充填した固定床にメタクリル酸含有物を流通させる連続式が好ましい。強酸性陽イオン交換樹脂の使用量は回分式ではメタクリル酸含有物１００重量部に対して、０．１〜５０重量部、特に１〜３０重量部の範囲が好ましく、連続式ではメタクリル酸含有物の流通量は強酸性陽イオン交換樹脂に対して空間速度で０．０１〜１０ｈｒ-1、特に０．０５〜５ｈｒ-1の範囲が好ましい。処理温度は２０〜１５０℃、特に４０〜１３０℃の範囲が好ましい。処理時間は５分〜５時間、特に１５分〜３時間の範囲が好ましい。
【００１６】
続いて、イオン交換樹脂処理された液は、ホルムアルデヒド含有物が添加され、強酸性陽イオン交換樹脂を充填した固定床に流通させることにより処理される。以下、この工程をホルムアルデヒド処理という。
【００１７】
ホルムアルデヒド処理で用いられるホルムアルデヒド含有物としては、ホルムアルデヒド、ホルムアルデヒド溶液のほか、パラホルムアルデヒド等のホルムアルデヒドを生成し得る化合物であれば何れも使用できるが、通常はホルマリンとして市販されているホルムアルデヒド水溶液が用いられる。ホルムアルデヒド含有物の使用量は、メタクリル酸含有物中のホルムアルデヒド含有率が１０〜１００００ｐｐｍ、特に５０〜５０００ｐｐｍとなる量が好ましい。
【００１８】
ホルムアルデヒド含有物を単独で用いた場合には微量不純物の除去効果が乏しく、強酸性陽イオン交換樹脂による処理を併せて行う必要がある。ここで強酸性陽イオン交換樹脂としては、前記のイオン交換樹脂処理で使用したものと同様に、通常スルホン酸基を有するものが用いられ、そのイオン交換容量および架橋度などに関して特に制限はない。また強酸性イオン交換樹脂の種類は、前記のイオン交換樹脂処理で使用したものと同じでも異なっていてもよい。
【００１９】
強酸性陽イオン交換樹脂による処理は、これを充填した固定床にホルムアルデヒド含有物を添加したメタクリル酸含有物を流通させて行う。流通量は強酸性陽イオン交換樹脂に対して空間速度で０．０１〜１０ｈｒ-1、特に０．０５〜５ｈｒ-1の範囲が好ましい。処理温度は２０〜１５０℃、特に４０〜１３０℃の範囲が好ましい。処理時間は５分〜５時間、特に１５分〜３時間の範囲が好ましい。
【００２０】
本発明において、上記３つの工程により処理された液は、最終的に常法の蒸留によって精製される。この蒸留工程において、未反応の処理剤、処理剤と着色要因物質および重合阻害要因物質との反応物が分離除去される。蒸留工程においては、例えば、フェノチアジン、ベンゾフェノチアジン等の重合禁止剤を添加しておくことが好ましい。
【００２１】
【実施例】
以下、本発明を実施例によりさらに詳しく説明するが、これらに限定されるものではない。下記実施例および比較例におけるメタクリル酸の純度は重量百分率を意味する。
【００２２】
メタクリル酸の回収率は、
回収率（％）=Ｂ／Ａ×１００
により定義され、式中のＡおよびＢは、
Ａ：精製処理前の粗製メタクリル酸含有物に含まれるメタクリル酸の重量
Ｂ：精製処理後の精製メタクリル酸に含まれるメタクリル酸の重量
を意味する。
【００２３】
誘導期間の測定は次のように行った。すなわち、試験管に測定対象の精製メタクリル酸１００ｍｌ、ヒドロキノンモノメチルエーテル５ｍｇおよび重合促進剤として過酸化ベンゾイル０．１ｇを加えて溶解する。これに水１０ｍｌを加え、温度６５℃の恒温槽に浸漬し、熱電対を用いて試験管内の液温を測定する。液温が６５℃より上昇した時点、つまり重合熱の発生し始めた時点を測定し、恒温槽に浸漬してから重合開始までに要した時間を誘導期間とする。重合性能は誘導期間が短いものほど優れている。
【００２４】
［実施例１］
イソブチレンを出発原料として気相接触酸化によって得られたメタクリル酸を抽出および蒸留によって精製し、純度９９．２％の粗メタクリル酸を得た。この粗メタクリル酸の色数はAPHA６３であった。この粗メタクリル酸１００ｇに重合禁止剤としてフェノチアジン０．０５ｇを添加し、これにエチレンジアミン０．０５ｇを添加して１００℃で２時間処理した。次いで１０mmHg減圧下で単蒸留し、得られたメタクリル酸に重合禁止剤としてハイドロキノン０．０２ｇを添加し、強酸性陽イオン交換樹脂アンバーリスト１５E（ロームアンドハース社製）２．５ｇを添加し、１００℃で１時間処理した。処理液からデカンテーションによってイオン交換樹脂を取り除いた液に、３５重量％のホルムアルデヒド水溶液をホルムアルデヒドの含有率が１００ｐｐｍとなるように添加した。５ｇのアンバーリスト１５Eを固定したガラス製Ｕ字管を８０℃の恒温中に保持し、ホルムアルデヒドを添加したメタクリル酸を空間速度０．２ｈｒ-1で連続的に流通させた。次いで、この通過液を１０mmHg減圧下で単蒸留して精製メタクリル酸を得た。得られた精製メタクリル酸の回収率は９４％、色数はAPHA３、誘導期間は８．０分であった。
【００２５】
［実施例２］
実施例１でエチレンジアミン０．０５ｇの代わりに、Ｎ，Ｎ’−ジフェニルエチレンジアミン０．１０ｇを使用した以外は実施例１と同じ条件で処理を行い精製メタクリル酸を得た。得られた精製メタクリル酸の回収率は９４．１％、色数はAPHA３、誘導期間は８．５分であった。
【００２６】
［実施例３］
実施例１でエチレンジアミン０．０５ｇの代わりに、ヒドラジン０．０３ｇおよびＮ，Ｎ’−ジフェニルエチレンジアミン０．０５ｇを使用した以外は実施例１と同じ条件で処理を行い精製メタクリル酸を得た。得られた精製メタクリル酸の回収率は９３．８％、色数はAPHA３、誘導期間は８．３分であった。
【００２７】
［実施例４〜１０］
ホルムアルデヒド処理工程におけるホルムアルデヒドの含有率および処理温度を表１の条件に変更した以外は、実施例１と同じ条件で処理を行い精製メタクリル酸を得た。その結果を表１に併せて示す。
【００２８】
【表１】
［比較例１］
実施例１において、陽イオン交換樹脂処理を省略すると、精製メタクリル酸の回収率は９３．９％、色数はAPHA５、誘導期間は２０分であった。このように、実施例１に比べて色数および誘導期間がともに悪化した。
【００３０】
［比較例２］
比較例１において、ホルムアルデヒドの含有率を５００ｐｐｍに増量したところ、精製メタクリル酸の回収率は８５．７％、色数はAPHA４、誘導期間は１２分であった。このように、比較例１に比べて色数および誘導期間は改善されるが、実施例１に比べると不十分であり、回収率は比較例１よりもむしろ悪化した。
【００３１】
［比較例３］
実施例１において、ホルムアルデヒド処理を省略すると、精製メタクリル酸の回収率は９３．７％、色数はAPHA１２、誘導期間は９．２分であった。このように、実施例１に比べて色数が悪化した。
【００３２】
［比較例４］
比較例３において、エチレンジアミンの使用量を０．５ｇに増量したところ、精製メタクリル酸の回収率は８１％、色数はAPHA３、誘導期間は８．５分であった。このように、比較例３に比べて色数および誘導期間は改善されるが、回収率はむしろ悪化した。
【００３３】
［比較例５］
実施例１において、アミン類処理を省略すると、精製メタクリル酸の回収率は９４．３％、色数はAPHA１５、誘導期間は１２分であった。このように、実施例１に比べて色数および誘導期間が悪化した。
【００３４】
【発明の効果】
本発明の方法を用いると、従来の方法に比べて少量の処理剤で、着色が少なく重合性能の優れたメタクリル酸を得ることができる。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to at least one compound selected from the group consisting of isobutylene, tertiary butyl alcohol and methyl tertiary butyl ether, or one compound selected from the group consisting of isobutane, methacrolein, isobutyraldehyde and isobutyric acid ( Hereinafter, the present invention also relates to a method for purifying a methacrylic acid-containing material obtained by a gas phase catalytic oxidation reaction of 4 carbon atoms.
[0002]
[Prior art]
Methacrylic acid-containing products obtained by gas-phase catalytic oxidation reactions such as isobutane, isobutylene, tertiary butyl alcohol, methyl tertiary butyl ether, methacrolein, isobutyraldehyde, isobutyric acid, etc. are impurities by ordinary purification means such as extraction and distillation. However, it is difficult to completely remove impurities present in a trace amount, so that coloring of the product cannot be completely prevented, and the polymerizability of the obtained product is remarkably inferior. There is a problem.
[0003]
Some of these trace impurities have a solubility in an extractant and a boiling point that is close to that of methacrylic acid, and it is extremely difficult to remove by only a purification method using physical means such as normal extraction and distillation. . Although it is possible to reduce the amount of trace impurities somewhat by techniques such as increasing the number of stages in the distillation column, such a method is complicated and the process is expensive, so it is almost impossible to adopt industrially. is there.
[0004]
Therefore, a method of combining a treatment with a sulfonic acid group-containing compound and a formaldehyde-containing material and a treatment with amines (Japanese Patent Publication No. 3-3645), a method of combining a treatment with a sulfonic acid group-containing compound and a treatment with amines (Japanese Patent Publication No. 3). No. 3646)) has been reported.
[0005]
However, in order to obtain methacrylic acid with little coloration and excellent polymerization performance by these methods, the former method requires a large amount of treating agent, and the latter method requires a large amount of amines and methacrylic acid to be used. Since the recovery rate of methacrylic acid decreased due to the reaction, there was a problem that all were poor in economic efficiency.
[0006]
[Problems to be solved by the invention]
An object of the present invention is to provide a method for purifying methacrylic acid, which can obtain methacrylic acid with little coloration and excellent polymerization performance with a small amount of treatment agent.
[0007]
[Means for Solving the Problems]
The present invention relates to a method for purifying a methacrylic acid-containing product obtained by vapor phase catalytic oxidation reaction of a compound having 4 carbon atoms by distillation, wherein the methacrylic acid-containing product is previously contained in a primary and / or secondary amino group. A methacrylic acid is characterized in that it is treated with a compound, treated with a strong acid cation exchange resin, then added with formaldehyde and passed through a fixed bed filled with a strong acid cation exchange resin, followed by distillation. It is in the purification method of the acid.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
The methacrylic acid-containing product to be purified of the present invention is at least one compound selected from the group consisting of isobutylene, tertiary butyl alcohol and methyl tertiary butyl ether, or isobutane, methacrolein, isobutyraldehyde and isobutyric acid. It is obtained by vapor phase catalytic oxidation of one kind of compound selected from the group consisting of Note that methyl tertiary butyl ether is immediately decomposed in the gas phase catalytic oxidation to obtain isobutylene and / or tertiary butyl alcohol.
[0009]
As the methacrylic acid-containing product obtained by vapor-phase catalytic oxidation of a compound having 4 carbon atoms, for example, separation and purification such as extraction and distillation are performed on a methacrylic acid aqueous solution obtained by vapor-phase catalytic oxidation of methacrolein, Although what concentrated the content rate of methacrylic acid to about 50 weight% or more is mentioned, it is not restrict | limited to this.
[0010]
A methacrylic acid-containing product obtained by vapor-phase catalytic oxidation of a compound having 4 carbon atoms is first treated with a primary and / or secondary amino group-containing compound. Hereinafter, this process is referred to as amine treatment.
[0011]
The primary or secondary amino group-containing compound used in the amine treatment may be any of aliphatic and aromatic amines, amines having a plurality of amino groups in one molecule, ammonia, hydrazine, and the like. This includes compounds such as hydroxylamine and its inorganic acid salts. Examples of such primary or secondary amino group-containing compounds include propylamine, butylamine, pentylamine, hexylamine, diethylamine, di-n-propylamine, diisopropylamine, methylethylamine, ethylenediamine, trimethylene. Diamine, tetramethylenediamine, pentamethylenediamine, N, N'-diphenylethylenediamine, ethanolamine, hexamethylenediamine, diethylenetriamine, tetraethylenepentamine, aniline, toluidine, N-ethylaniline, N-propylamine, diphenylamine, phenylenediamine , N-methylphenylenediamine, benzylamine, phenethylamine, anisidine and the like.
[0012]
The primary and / or secondary amino group-containing compounds may be used alone, or two or more compounds may be used in appropriate combination. Moreover, the addition amount of the primary and / or secondary amino group-containing compound is 0.001 to 1 part by weight, particularly 0.005 to 0.8 part by weight, with respect to 100 parts by weight of the methacrylic acid-containing compound. The range of is preferable.
[0013]
The amine treatment usually requires a heat treatment, and it is preferable to perform the heat treatment at a temperature of 50 to 150 ° C., particularly 80 to 130 ° C. The treatment time at this time is preferably in the range of 5 minutes to 5 hours, particularly 15 minutes to 3 hours. As a method for treating amines, for example, a primary and / or secondary amino group-containing compound is added to a methacrylic acid-containing material and heated to a predetermined temperature, and then the mixture is preferably stirred while stirring. Although the method of hold | maintaining time is mentioned, It is not limited to this.
[0014]
The solution treated with amines may be subjected to the next treatment as it is, but it is preferable to carry out the next treatment after distillation.
[0015]
The solution treated with amines is then treated with a strongly acidic cation exchange resin. Hereinafter, this process is referred to as ion exchange resin treatment. Here, as the strongly acidic cation exchange resin, those having a sulfonic acid group are usually used, and there are no particular restrictions on the ion exchange capacity and the degree of crosslinking. Either a batch type or a continuous type may be used as a method for the ion exchange resin treatment, but industrially, a continuous type in which a methacrylic acid-containing material is circulated through a fixed bed filled with a strongly acidic cation exchange resin is preferable. The amount of the strongly acidic cation exchange resin used is preferably in the range of 0.1 to 50 parts by weight, particularly 1 to 30 parts by weight with respect to 100 parts by weight of the methacrylic acid-containing product in a batch system, and methacrylic acid-containing product in a continuous system. the amount of circulation 0.01～10Hr -1 in space velocity relative to the strong acid cation exchange resins, in particular in the range of 0.05～5Hr -1 are preferred. The treatment temperature is preferably 20 to 150 ° C, particularly 40 to 130 ° C. The treatment time is preferably in the range of 5 minutes to 5 hours, particularly 15 minutes to 3 hours.
[0016]
Subsequently, the liquid subjected to the ion exchange resin treatment is treated by adding the formaldehyde-containing material to the fixed bed filled with the strong acid cation exchange resin. Hereinafter, this process is referred to as formaldehyde treatment.
[0017]
As the formaldehyde-containing material used in the formaldehyde treatment, in addition to formaldehyde and formaldehyde solution, any compound that can formaldehyde such as paraformaldehyde can be used, but usually an aqueous formaldehyde solution commercially available as formalin is used. . The amount of formaldehyde-containing material used is preferably such that the formaldehyde content in the methacrylic acid-containing material is 10 to 10,000 ppm, particularly 50 to 5000 ppm.
[0018]
When the formaldehyde-containing material is used alone, the effect of removing trace impurities is poor, and it is necessary to perform treatment with a strongly acidic cation exchange resin. Here, as the strong acid cation exchange resin, those having a sulfonic acid group are usually used in the same manner as those used in the above ion exchange resin treatment, and the ion exchange capacity and the degree of crosslinking are not particularly limited. Moreover, the kind of strong acidic ion exchange resin may be the same as that used by the said ion exchange resin process, or may differ.
[0019]
The treatment with the strongly acidic cation exchange resin is carried out by circulating a methacrylic acid-containing material to which a formaldehyde-containing material is added on a fixed bed filled with this. Weight distribution is 0.01～10Hr -1 in space velocity relative to the strong acid cation exchange resins, in particular in the range of 0.05～5Hr -1 are preferred. The treatment temperature is preferably 20 to 150 ° C, particularly 40 to 130 ° C. The treatment time is preferably in the range of 5 minutes to 5 hours, particularly 15 minutes to 3 hours.
[0020]
In the present invention, the liquid treated in the above three steps is finally purified by conventional distillation. In this distillation step, the unreacted processing agent, and the reaction product of the processing agent, the coloring factor substance, and the polymerization inhibiting factor substance are separated and removed. In the distillation step, for example, it is preferable to add a polymerization inhibitor such as phenothiazine or benzophenothiazine.
[0021]
【Example】
EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, it is not limited to these. The purity of methacrylic acid in the following examples and comparative examples means weight percentage.
[0022]
The recovery rate of methacrylic acid is
Recovery rate (%) = B / A × 100
Where A and B are
A: Weight of methacrylic acid contained in crude methacrylic acid-containing material before purification treatment B: Meaning weight of methacrylic acid contained in purified methacrylic acid after purification treatment.
[0023]
The induction period was measured as follows. That is, 100 ml of purified methacrylic acid to be measured, 5 mg of hydroquinone monomethyl ether and 0.1 g of benzoyl peroxide as a polymerization accelerator are added to a test tube and dissolved. 10 ml of water is added to this, immersed in a thermostatic bath at a temperature of 65 ° C., and the liquid temperature in the test tube is measured using a thermocouple. The time when the liquid temperature rises from 65 ° C., that is, the time when the polymerization heat starts to be generated is measured, and the time required from the immersion in the thermostat until the start of polymerization is taken as the induction period. The shorter the induction period, the better the polymerization performance.
[0024]
[Example 1]
Methacrylic acid obtained by gas phase catalytic oxidation using isobutylene as a starting material was purified by extraction and distillation to obtain crude methacrylic acid having a purity of 99.2%. The color number of this crude methacrylic acid was APHA63. To 100 g of this crude methacrylic acid, 0.05 g of phenothiazine was added as a polymerization inhibitor, and 0.05 g of ethylenediamine was added thereto, followed by treatment at 100 ° C. for 2 hours. Next, simple distillation under reduced pressure of 10 mmHg, 0.02 g of hydroquinone was added as a polymerization inhibitor to the resulting methacrylic acid, 2.5 g of strongly acidic cation exchange resin Amberlyst 15E (Rohm and Haas) was added, Treated at 100 ° C. for 1 hour. A 35% by weight aqueous formaldehyde solution was added to the liquid obtained by removing the ion exchange resin from the treatment liquid by decantation so that the formaldehyde content was 100 ppm. A glass U-tube fixed with 5 g of Amberlyst 15E was kept at a constant temperature of 80 ° C., and methacrylic acid added with formaldehyde was continuously circulated at a space velocity of 0.2 hr −1 . Next, this passing liquid was simply distilled under reduced pressure of 10 mmHg to obtain purified methacrylic acid. The recovery rate of the obtained purified methacrylic acid was 94%, the number of colors was APHA3, and the induction period was 8.0 minutes.
[0025]
[Example 2]
Purified methacrylic acid was obtained in the same manner as in Example 1 except that 0.10 g of N, N′-diphenylethylenediamine was used instead of 0.05 g of ethylenediamine in Example 1. The recovery rate of the obtained purified methacrylic acid was 94.1%, the color number was APHA3, and the induction period was 8.5 minutes.
[0026]
[Example 3]
In Example 1, in place of 0.05 g of ethylenediamine, 0.03 g of hydrazine and 0.05 g of N, N′-diphenylethylenediamine were used to carry out the treatment under the same conditions as in Example 1 to obtain purified methacrylic acid. The recovery rate of the obtained purified methacrylic acid was 93.8%, the number of colors was APHA3, and the induction period was 8.3 minutes.
[0027]
[Examples 4 to 10]
Purified methacrylic acid was obtained by treatment under the same conditions as in Example 1 except that the formaldehyde content and the treatment temperature in the formaldehyde treatment step were changed to the conditions shown in Table 1. The results are also shown in Table 1.
[0028]
[Table 1]
[Comparative Example 1]
In Example 1, when the cation exchange resin treatment was omitted, the recovery rate of purified methacrylic acid was 93.9%, the number of colors was APHA5, and the induction period was 20 minutes. As described above, both the number of colors and the induction period were deteriorated as compared with Example 1.
[0030]
[Comparative Example 2]
In Comparative Example 1, when the formaldehyde content was increased to 500 ppm, the recovery of purified methacrylic acid was 85.7%, the number of colors was APHA4, and the induction period was 12 minutes. Thus, although the number of colors and the induction period were improved as compared with Comparative Example 1, it was insufficient as compared with Example 1, and the recovery rate was worse than that of Comparative Example 1.
[0031]
[Comparative Example 3]
In Example 1, when formaldehyde treatment was omitted, the recovery rate of purified methacrylic acid was 93.7%, the color number was APHA12, and the induction period was 9.2 minutes. Thus, the number of colors deteriorated compared to Example 1.
[0032]
[Comparative Example 4]
In Comparative Example 3, when the amount of ethylenediamine used was increased to 0.5 g, the recovery rate of purified methacrylic acid was 81%, the number of colors was APHA3, and the induction period was 8.5 minutes. Thus, although the number of colors and the induction period were improved as compared with Comparative Example 3, the recovery rate was rather deteriorated.
[0033]
[Comparative Example 5]
In Example 1, when the treatment with amines was omitted, the recovery rate of purified methacrylic acid was 94.3%, the number of colors was APHA15, and the induction period was 12 minutes. Thus, the number of colors and the induction period deteriorated compared to Example 1.
[0034]
【The invention's effect】
When the method of the present invention is used, it is possible to obtain methacrylic acid which is less colored and excellent in polymerization performance with a small amount of treatment agent compared with the conventional method.
Claims (1)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP21611997A JP3871406B2 (en) | 1997-08-11 | 1997-08-11 | Method for purifying methacrylic acid |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP21611997A JP3871406B2 (en) | 1997-08-11 | 1997-08-11 | Method for purifying methacrylic acid |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH1160536A JPH1160536A (en) | 1999-03-02 |
| JP3871406B2 true JP3871406B2 (en) | 2007-01-24 |
Family
ID=16683555
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP21611997A Expired - Lifetime JP3871406B2 (en) | 1997-08-11 | 1997-08-11 | Method for purifying methacrylic acid |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3871406B2 (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP4581395B2 (en) * | 2003-12-24 | 2010-11-17 | 三菱化学株式会社 | Method for purifying (meth) acrylic acid and method for producing (meth) acrylic acid ester |
| JP2008161848A (en) * | 2007-01-04 | 2008-07-17 | Mitsubishi Rayon Co Ltd | Vertical-type multi-blades reaction tank and purification method of (meth)acrylic acid |
| RU2523228C2 (en) | 2008-12-18 | 2014-07-20 | ЛУСАЙТ ИНТЕРНЭШНЛ ЮКей ЛИМИТЕД | Method of methyl methacrylate purification |
| WO2013163806A1 (en) | 2012-05-03 | 2013-11-07 | Evonik Industries Ag | Process for preparation of highly pure, non-yellowing methacrylic acid |
-
1997
- 1997-08-11 JP JP21611997A patent/JP3871406B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH1160536A (en) | 1999-03-02 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP3835843B2 (en) | Method for producing pure grade acrylic acid | |
| JPH07149687A (en) | Purification of (meth)acrylic acid contaminated with aldehyde | |
| JP6895954B2 (en) | Improved method for the production of polymer grade (meth) acrylic acid | |
| US5705675A (en) | Processes for the preparation of 3-(methylthio)propanal and 2-hydroxy-4-(methylthio)butanenitrile | |
| JP3871406B2 (en) | Method for purifying methacrylic acid | |
| JP6779288B2 (en) | Method for synthesizing acrylic acid oligomer | |
| AU714151B2 (en) | Processes for the preparation of 3-(methylthio)propanal and 2-hydroxy-4-(methylthio)butanenitrile | |
| EP0085898B1 (en) | Removal of trace aldehyde from unsaturated carboxylic acids | |
| JP3792449B2 (en) | Purification method of methacrylic acid | |
| JP2008161848A (en) | Vertical-type multi-blades reaction tank and purification method of (meth)acrylic acid | |
| JP3792448B2 (en) | Purification method of methacrylic acid | |
| JP2002194022A (en) | Method for purifying (meth) acrylate ester, (meth) acrylate ester and (meth)acrylic resin | |
| JP4733275B2 (en) | (Meth) acrylic acid ester purification method | |
| KR910002222B1 (en) | Purification process of methacrylic acid | |
| JP3222068B2 (en) | Purification method of methacrylic acid | |
| CA2088106A1 (en) | Method of reducing impurities in aqueous acrylic monomer solutions | |
| CN105793232A (en) | Process for ruthenium-catalysed transvinylation of carboxylic acids | |
| US5358611A (en) | Method of reducing impurities in aqueous monomer solutions | |
| JP4942878B2 (en) | (Meth) acrylic acid ester purification method | |
| JP3826435B2 (en) | Purification method of acrylic acid or methacrylic acid | |
| JP4551044B2 (en) | Treatment of nitriles with glycolic acid | |
| JPS5948438A (en) | Purification of methacrylic acid | |
| JPS63190862A (en) | Recovery of n-vinylformamide | |
| JPS647064B2 (en) | ||
| JP4601120B2 (en) | Acrylic acid production method |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A131 | Notification of reasons for refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A131 Effective date: 20041221 |
|
| A521 | Written amendment |
Free format text: JAPANESE INTERMEDIATE CODE: A523 Effective date: 20050221 |
|
| TRDD | Decision of grant or rejection written | ||
| A01 | Written decision to grant a patent or to grant a registration (utility model) |
Free format text: JAPANESE INTERMEDIATE CODE: A01 Effective date: 20061010 |
|
| A61 | First payment of annual fees (during grant procedure) |
Free format text: JAPANESE INTERMEDIATE CODE: A61 Effective date: 20061017 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20091027 Year of fee payment: 3 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20101027 Year of fee payment: 4 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20101027 Year of fee payment: 4 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20111027 Year of fee payment: 5 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20111027 Year of fee payment: 5 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20111027 Year of fee payment: 5 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20121027 Year of fee payment: 6 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20121027 Year of fee payment: 6 |
|
| S531 | Written request for registration of change of domicile |
Free format text: JAPANESE INTERMEDIATE CODE: R313531 |
|
| R350 | Written notification of registration of transfer |
Free format text: JAPANESE INTERMEDIATE CODE: R350 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20121027 Year of fee payment: 6 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20131027 Year of fee payment: 7 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| EXPY | Cancellation because of completion of term |