JPH0621103B2 - Methacrylic acid recovery method - Google Patents
Methacrylic acid recovery methodInfo
- Publication number
- JPH0621103B2 JPH0621103B2 JP2397986A JP2397986A JPH0621103B2 JP H0621103 B2 JPH0621103 B2 JP H0621103B2 JP 2397986 A JP2397986 A JP 2397986A JP 2397986 A JP2397986 A JP 2397986A JP H0621103 B2 JPH0621103 B2 JP H0621103B2
- Authority
- JP
- Japan
- Prior art keywords
- methacrylic acid
- weight
- boiling point
- polymer
- parts
- 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 - Fee Related
Links
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- Extraction Or Liquid Replacement (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Description
【発明の詳細な説明】 〔産業上の利用分野〕 本発明はメタクリル酸の回収法に関する。更に詳しくは
メタクリ酸を蒸留分離した缶残液から、メタクリル酸を
回収する方法に関する。TECHNICAL FIELD The present invention relates to a method for recovering methacrylic acid. More specifically, it relates to a method for recovering methacrylic acid from a bottom liquid obtained by distilling and separating methacrylic acid.
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を水蒸気の存在下に分子状酸素
で1段または2段の反応で接触酸化して得られるメタク
リル酸は抽出及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。Methacrylic acid obtained by catalytic oxidation of isobutylene, tertiary butanol, methacrolein or isobutyraldehyde with molecular oxygen in the presence of steam in a one-step or two-step reaction can be highly purified by conventional purification means such as extraction and distillation. It can be a pure product.
しかし、最終的にメタクリル酸を得るまでにはメタクリ
ル酸水溶液からアルデヒド類及びケトン類等の軽沸点成
分の除去、抽出処理後の溶剤回収、メタクリル酸よりも
低沸点の酸の分離そして高沸点成分の分離と幾度となく
加熱状態に曝される。そのため各工程の処理はフェノチ
アジン、ベンゾフェノチアジン、ハイドロキノン、メト
キシハイドロキノン、メチレンブルーおよび分子状酸素
など従来公知の重合禁止剤存在下に遂行されてはいる
が、メタクリル酸等の重合を完全に抑制することはでき
ず工程を経るごとにメタクリル酸等の重合物および重合
禁止剤等が徐々に蓄積され、最終工程では無視できない
量となる。However, until methacrylic acid is finally obtained, removal of light-boiling components such as aldehydes and ketones from methacrylic acid aqueous solution, recovery of solvent after extraction treatment, separation of acids having a lower boiling point than methacrylic acid, and high-boiling components And is repeatedly exposed to heating conditions. Therefore, the treatment of each step is carried out in the presence of a conventionally known polymerization inhibitor such as phenothiazine, benzophenothiazine, hydroquinone, methoxyhydroquinone, methylene blue and molecular oxygen, but it is not possible to completely suppress the polymerization of methacrylic acid or the like. This cannot be done, and the polymer such as methacrylic acid and the polymerization inhibitor are gradually accumulated with each step, and the amount becomes nonnegligible in the final step.
したがって、メタクリル酸を精留留去した後の缶残液中
には反応によって生成した高沸点不純物の他に相当量の
重合物や重合禁止剤等が存在するため、メタクリル酸の
留出率(留出量/供給量)を高くしすぎると缶部の液粘
度が上昇し、再沸器の熱効率の悪化、更にはメタクリル
酸等の重合を助長する結果となる。Therefore, in the bottom liquid after the methacrylic acid has been distilled off by rectification, a considerable amount of a polymer and a polymerization inhibitor are present in addition to the high-boiling-point impurities generated by the reaction. If the amount of distillate / supply is too high, the liquid viscosity of the can portion rises, the thermal efficiency of the reboiler deteriorates, and the polymerization of methacrylic acid and the like is promoted.
そこで、必然的にメタクリル酸の留出率をある範囲以下
に抑えることになり、缶残液として重合物を含む高沸点
成分と共に相当量のメタクリル酸を排出することにな
る。したがって、該缶残液を廃棄または焼却するとメタ
クリル酸の損失をまねき、ひいては原単位の悪化、コス
ト増につながるために何等かの方法でメタクリル酸の回
収を計らねばならない。Therefore, the distillation rate of methacrylic acid is necessarily suppressed below a certain range, and a considerable amount of methacrylic acid is discharged together with the high-boiling point component containing the polymer as a bottom liquid. Therefore, if the residual liquid in the can is discarded or incinerated, loss of methacrylic acid is caused, which leads to deterioration of the basic unit and increase in cost. Therefore, recovery of methacrylic acid must be done by some method.
従来、一般的な方法として蒸発缶等による缶残液の再蒸
発によるメタクリル酸の回収または有機溶剤抽出による
メタクリル酸の回収等が考えられてきた。しかし、前者
は回収率の悪さやメタクリル酸の重合に起因する操業上
の問題などがあり、また後者は抽出溶剤により多量の浮
滓が生成し、エマルジョン化や抽出塔のフラッデイング
が発生するなど、いずれも有効な方法とは言えない。Heretofore, as a general method, recovery of methacrylic acid by re-evaporation of a bottom liquid in an evaporator or recovery of methacrylic acid by extraction with an organic solvent has been considered. However, the former has problems such as poor recovery rate and operational problems due to polymerization of methacrylic acid, and the latter causes a large amount of sludge to be generated by the extraction solvent, resulting in emulsification and flooding of the extraction tower. However, none of them are effective methods.
[発明が解決しようとする問題点] したがって、本発明の目的はメタクリル酸蒸留の缶残液
からメタクリル酸を容易に、かつ効率よく回収するため
の方法を提供することにある。[Problems to be Solved by the Invention] Therefore, an object of the present invention is to provide a method for easily and efficiently recovering methacrylic acid from a bottom liquid of a methacrylic acid distillation.
本発明者らは、この点に着目し、メタクリル酸を蒸留分
離した後の重合物及び高沸点成分を含む缶残液からメタ
クリル酸を効果的に回収する方法について鋭意研究した
結果、水を前記缶残液に添加すると高沸点アルデヒド
類、重合物、重合禁止剤等の高沸点成分の大部分がメタ
クリル酸水溶液から選択的に二層分離し、メタクリル酸
を容易に、かつ効率よく回収できることを見出し、その
知見に基づき本発明を完成した。The present inventors focused their attention on this point, and as a result of earnest research on a method for effectively recovering methacrylic acid from a bottoms solution containing a polymer and a high-boiling component after methacrylic acid was separated by distillation, as a result, When added to the bottom liquid, most of the high-boiling components such as high-boiling aldehydes, polymers, and polymerization inhibitors are selectively separated into two layers from the aqueous methacrylic acid solution, and methacrylic acid can be recovered easily and efficiently. The present invention has been completed based on the findings and the findings.
本発明のメタクリル酸の回収法はメタクリル酸60〜9
5重量部、高沸点物3〜30重量部および重合物2〜1
0重量部からなる、メタクリル酸を蒸留分離した缶残液
に水を添加し、重合物及び高沸点成分の層とメタクリル
酸水溶液層とに二層分離し、該メタクリル酸水溶液から
メタクリル酸を有機溶剤で抽出して回収することを特徴
とするものである。Methacrylic acid recovery method of the present invention is methacrylic acid 60-9
5 parts by weight, high boiling substance 3 to 30 parts by weight and polymer 2-1
Water was added to 0 parts by weight of the bottoms obtained by distillation to separate methacrylic acid, and two layers were separated into a layer of the polymer and the high boiling point component and a methacrylic acid aqueous solution layer. It is characterized by being extracted with a solvent and recovered.
分離されたメタクリル酸水溶液からメタクリル酸を分離
する方法としては蒸留、抽出、半透膜等による方法が適
用できるが、このメタクリル酸水溶液は少量の親水性の
高沸点成分を含有しているため、ここからメタクリル酸
を純度良くかつ低コストで回収するためには特定の有機
溶剤によってメタクリル酸を抽出する方法が最も効果的
である。As a method for separating methacrylic acid from the separated methacrylic acid aqueous solution, distillation, extraction, a method such as semipermeable membrane can be applied, but since this methacrylic acid aqueous solution contains a small amount of hydrophilic high-boiling point component, The method of extracting methacrylic acid with a specific organic solvent is the most effective for recovering methacrylic acid from here with high purity and at low cost.
本発明の方法が対象とする缶残液は、公知の種々の方法
により得られたメタクリル酸を蒸留して得られた缶残液
が使用可能である。例えば、イソブチレン、第三級ブタ
ノール、メタクロレインまたはイソブチルアルデヒドを
水蒸気の存在下に分子状酸素を含有するガスにより接触
酸化しこの酸化生成物を冷却することにより得られるメ
タクリル酸水溶液から、溶媒によるメタクリル酸の抽
出、溶媒の回収、メタクリル酸の蒸留分離をした缶残液
である。As the bottoms solution targeted by the method of the present invention, bottoms solutions obtained by distilling methacrylic acid obtained by various known methods can be used. For example, isobutylene, tert-butanol, methacrolein or isobutyraldehyde is catalytically oxidized with a gas containing molecular oxygen in the presence of water vapor, and the methacrylic acid aqueous solution obtained by cooling the oxidation product is treated with a methacrylic acid by a solvent. It is a bottom liquid obtained by acid extraction, solvent recovery, and methacrylic acid distillation separation.
缶残液の組成は通常メタクリル酸60〜95重量部、高沸点
物3〜30重量部および重合物2〜10重量部である。本発
明においては、この組織の缶残液が用いられる。缶残液
中の高沸点成分はシトラコン酸、マレイン酸、テレフタ
ル酸、トリメリット酸等の酸類、P−トルアルデヒド、
ベンズアルデヒド等のアルデヒド類、及び重合禁止剤と
して添加されたハイドロキノン等であり、また重合物は
メタクリル酸の重合物である。The composition of the bottom liquid is usually 60 to 95 parts by weight of methacrylic acid, 3 to 30 parts by weight of a high-boiling substance, and 2 to 10 parts by weight of a polymer. In the present invention, the bottom solution of this structure is used. The high-boiling components in the bottom liquid are citraconic acid, maleic acid, terephthalic acid, trimellitic acid and other acids, P-tolualdehyde,
Aldehydes such as benzaldehyde, and hydroquinone added as a polymerization inhibitor, and the polymer is a polymer of methacrylic acid.
本発明において、缶残液に添加される水の量は缶残液の
組成によって異なるが、通常缶残液に対し2〜6倍量
(重量)が採用される。2倍量(重量)より少ない場合
も6倍量(重量)を超えて使用する場合も均一溶液のま
まで二層分離せず、本発明の目的を果たすことができな
い。In the present invention, the amount of water to be added to the bottom liquor varies depending on the composition of the bottom liquor, but is usually 2 to 6 times the weight (weight) of the bottom liquor. When the amount is less than 2 times the weight (weight) or when the amount is more than 6 times the weight (weight), the two layers are not separated as a homogeneous solution and the object of the present invention cannot be achieved.
本発明において、メタクリル酸の抽出に用いる有機溶剤
としては、非水溶性でかつメタクリル酸より低沸点の有
機溶剤、例えば脂肪族炭化水素類、脂環式炭化水素類、
芳香族炭化水素類、酢酸エステル類エーテレ類か使用で
き、特に好ましくは、n−ペンタン、n−ヘプタン、n
−ヘキサンおよびn−オクタン、シクロヘキサン、トル
エン、エチルベンゼンおよびキシレン等を挙げることが
できる。In the present invention, the organic solvent used to extract methacrylic acid is a water-insoluble organic solvent having a lower boiling point than methacrylic acid, for example, aliphatic hydrocarbons, alicyclic hydrocarbons,
Aromatic hydrocarbons, acetic acid esters or ethers can be used, and particularly preferably n-pentane, n-heptane, n
-Hexane and n-octane, cyclohexane, toluene, ethylbenzene, xylene and the like can be mentioned.
缶残液に水を添加することによって二層分離して得られ
たメタクリル酸水溶液からメタクリル酸を上記有機溶剤
で抽出することによって大部分の水と親水性高沸点成分
とを抽残液として分離除去して廃水処理設備によって処
理することができる。Most of the water and hydrophilic high-boiling point components are separated as a raffinate by extracting methacrylic acid with the above organic solvent from the methacrylic acid aqueous solution obtained by separating the two layers by adding water to the bottom liquid. It can be removed and treated by a wastewater treatment facility.
一方、抽出液として得られたメタクリル酸の有機溶剤溶
液は蒸留によって有機溶剤を分離することによりメタク
リル酸を低コストで回収することができる。On the other hand, the organic solvent solution of methacrylic acid obtained as the extract can be recovered at low cost by separating the organic solvent by distillation.
本発明の方法によれば従来缶残液として高沸点成分およ
び重合物と共に廃棄または焼却されていたメタクリル酸
を容易に、かつ、効率的に回収することができる。According to the method of the present invention, methacrylic acid, which has been conventionally discarded or incinerated together with a high boiling point component and a polymer as a bottom liquid, can be easily and efficiently recovered.
以下に実施例をあげて本発明をさらに具体的に説明す
る。Hereinafter, the present invention will be described more specifically with reference to examples.
実施例1 メタクリル酸93.84%、重合物および高沸点成分を6.16
%からなるメタクリル酸精留塔の缶残液25kgに水75kgを
加えて十分に撹拌し静置したところ、メタクリル酸22.5
4%、高沸点成分0.48%、および水76.98%の組成を有す
る上層液94.73kgと、メタクリル酸40.04%、高沸点成分
20.49%、水39.47%の組成を有する下層液5.27kgとに層
分離した溶液を得た。メタクリル酸の回収率は91.0%、
高沸点成分の除去率は70.1%であった。Example 1 Methacrylic acid 93.84%, polymer and high boiling point component 6.16
% Of methacrylic acid rectification column containing 75% of water was added to 75 kg of water, and the mixture was sufficiently stirred and allowed to stand.
94.73 kg of upper layer liquid having a composition of 4%, high boiling point component 0.48%, and water 76.98%, methacrylic acid 40.04%, high boiling point component
A layer-separated solution was obtained with 5.27 kg of a lower layer liquid having a composition of 20.49% and water 39.47%. The recovery rate of methacrylic acid is 91.0%,
The removal rate of high-boiling components was 70.1%.
上層液を実段数20段の回転円盤抽出塔等の塔頂へ2.0kg
/hrの流速で供給し、塔底へ2.0kg/hrの流速でn−ヘ
キサンを供給する。両者を向流接触せしめて塔頂からメ
タクリル酸18.00%、n−ヘキサン81.91%、高沸点成分
120ppmおよび水820ppmの抽出液2.44kg/hrを、塔底から
メタクリル酸0.72%、高沸点成分0.60%および水98.68
%の抽残液1.56kg/hrを得た。メタクリル酸の回収率は
97.5%、高沸点成分の除去率は96.9%であった。両工程
を通じての最終的なメタクリル酸の回収率は88.7%、高
沸点成分の除去率は99.1%であった。2.0 kg of upper layer liquid to the top of a rotating disk extraction tower with 20 actual stages
/ N-hexane at a flow rate of 2.0 kg / hr. Both of them are brought into countercurrent contact and from the top of the column, methacrylic acid 18.00%, n-hexane 81.91%, high boiling point component.
Extraction liquid 2.44 kg / hr of 120 ppm and water 820 ppm is passed from the bottom of the tower to 0.72% of methacrylic acid, 0.60% of high boiling point component and 98.68 of water.
% Raffinate was obtained at 1.56 kg / hr. The recovery rate of methacrylic acid is
The removal rate of high-boiling components was 97.5% and 96.9%. The final methacrylic acid recovery rate through both steps was 88.7%, and the high boiling point component removal rate was 99.1%.
実施例2〜5 表−1に示した2種類の缶残液を原料として、水の添加
量及び溶剤の種類および添加量を変えて実施例1と同様
の処理を行なった結果を実施例1の結果も含め表−1に
示す。Examples 2 to 5 The results obtained by carrying out the same treatment as in Example 1 using the two types of bottom liquids shown in Table 1 as raw materials and changing the addition amount of water and the type and addition amount of solvent are shown in Example 1. The results are shown in Table-1.
───────────────────────────────────────────────────── フロントページの続き (72)発明者 越部 実 大阪府堺市新桧尾台1−3−16 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Minoru Koshibe 1-3-16 Shinhiodai, Sakai City, Osaka Prefecture
Claims (2)
3〜30重量部および重合物2〜10重量部からなる、
メタクリル酸を蒸留分離した缶残液に水を添加し、重合
物および高沸点成分の層とメタクリル酸水溶液層とに二
層分離し、該メタクリル酸水溶液からメタクリル酸を有
機溶剤で抽出して回収することを特徴とするメタクリル
酸の回収方法。1. Methacrylic acid 60 to 95 parts by weight, high boiling point material 3 to 30 parts by weight and polymer 2 to 10 parts by weight,
Water is added to the bottom liquid obtained by distilling and separating methacrylic acid, and two layers are separated into a polymer layer and a high boiling point component layer and a methacrylic acid aqueous solution layer, and methacrylic acid is extracted from the methacrylic acid aqueous solution with an organic solvent and recovered. A method for recovering methacrylic acid, which comprises:
n−ヘプタン、n−オクタン、シクロヘキサン、トルエ
ン、エチルベンゼンまたはキシレンである特許請求の範
囲第1項記載の方法。2. The organic solvent is n-pentane, n-hexane,
A process according to claim 1 which is n-heptane, n-octane, cyclohexane, toluene, ethylbenzene or xylene.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2397986A JPH0621103B2 (en) | 1986-02-07 | 1986-02-07 | Methacrylic acid recovery method |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2397986A JPH0621103B2 (en) | 1986-02-07 | 1986-02-07 | Methacrylic acid recovery method |
Publications (2)
Publication Number | Publication Date |
---|---|
JPS62185040A JPS62185040A (en) | 1987-08-13 |
JPH0621103B2 true JPH0621103B2 (en) | 1994-03-23 |
Family
ID=12125675
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP2397986A Expired - Fee Related JPH0621103B2 (en) | 1986-02-07 | 1986-02-07 | Methacrylic acid recovery method |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPH0621103B2 (en) |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP5432852B2 (en) * | 2009-09-30 | 2014-03-05 | ローム アンド ハース カンパニー | Process for recovering valuable compounds from streams resulting from the purification of methyl methacrylate |
-
1986
- 1986-02-07 JP JP2397986A patent/JPH0621103B2/en not_active Expired - Fee Related
Also Published As
Publication number | Publication date |
---|---|
JPS62185040A (en) | 1987-08-13 |
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