JPH0580462B2 - - Google Patents
Info
- Publication number
- JPH0580462B2 JPH0580462B2 JP28438885A JP28438885A JPH0580462B2 JP H0580462 B2 JPH0580462 B2 JP H0580462B2 JP 28438885 A JP28438885 A JP 28438885A JP 28438885 A JP28438885 A JP 28438885A JP H0580462 B2 JPH0580462 B2 JP H0580462B2
- Authority
- JP
- Japan
- Prior art keywords
- acid
- methacrylic acid
- solvent
- separation column
- column
- 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
- CERQOIWHTDAKMF-UHFFFAOYSA-N Methacrylic acid Chemical compound CC(=C)C(O)=O CERQOIWHTDAKMF-UHFFFAOYSA-N 0.000 claims description 58
- 239000002904 solvent Substances 0.000 claims description 40
- XBDQKXXYIPTUBI-UHFFFAOYSA-N dimethylselenoniopropionate Natural products CCC(O)=O XBDQKXXYIPTUBI-UHFFFAOYSA-N 0.000 claims description 36
- KQNPFQTWMSNSAP-UHFFFAOYSA-N isobutyric acid Chemical compound CC(C)C(O)=O KQNPFQTWMSNSAP-UHFFFAOYSA-N 0.000 claims description 36
- 238000000926 separation method Methods 0.000 claims description 35
- SMZOUWXMTYCWNB-UHFFFAOYSA-N 2-(2-methoxy-5-methylphenyl)ethanamine Chemical compound COC1=CC=C(C)C=C1CCN SMZOUWXMTYCWNB-UHFFFAOYSA-N 0.000 claims description 20
- NIXOWILDQLNWCW-UHFFFAOYSA-N 2-Propenoic acid Natural products OC(=O)C=C NIXOWILDQLNWCW-UHFFFAOYSA-N 0.000 claims description 20
- 238000009835 boiling Methods 0.000 claims description 20
- 235000019260 propionic acid Nutrition 0.000 claims description 18
- IUVKMZGDUIUOCP-BTNSXGMBSA-N quinbolone Chemical compound O([C@H]1CC[C@H]2[C@H]3[C@@H]([C@]4(C=CC(=O)C=C4CC3)C)CC[C@@]21C)C1=CCCC1 IUVKMZGDUIUOCP-BTNSXGMBSA-N 0.000 claims description 18
- 238000000605 extraction Methods 0.000 claims description 17
- 150000007933 aliphatic carboxylic acids Chemical class 0.000 claims description 16
- 238000011084 recovery Methods 0.000 claims description 7
- 239000007788 liquid Substances 0.000 claims description 6
- 238000004821 distillation Methods 0.000 claims description 5
- 238000000034 method Methods 0.000 claims description 5
- 239000002253 acid Substances 0.000 claims description 4
- 150000001735 carboxylic acids Chemical class 0.000 claims description 2
- 238000004064 recycling Methods 0.000 claims description 2
- QTBSBXVTEAMEQO-UHFFFAOYSA-N Acetic acid Chemical compound CC(O)=O QTBSBXVTEAMEQO-UHFFFAOYSA-N 0.000 description 48
- IMNFDUFMRHMDMM-UHFFFAOYSA-N N-Heptane Chemical compound CCCCCCC IMNFDUFMRHMDMM-UHFFFAOYSA-N 0.000 description 7
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 7
- 239000007864 aqueous solution Substances 0.000 description 5
- VLKZOEOYAKHREP-UHFFFAOYSA-N n-Hexane Chemical compound CCCCCC VLKZOEOYAKHREP-UHFFFAOYSA-N 0.000 description 5
- AMIMRNSIRUDHCM-UHFFFAOYSA-N Isopropylaldehyde Chemical compound CC(C)C=O AMIMRNSIRUDHCM-UHFFFAOYSA-N 0.000 description 4
- STNJBCKSHOAVAJ-UHFFFAOYSA-N Methacrolein Chemical compound CC(=C)C=O STNJBCKSHOAVAJ-UHFFFAOYSA-N 0.000 description 4
- 239000012535 impurity Substances 0.000 description 4
- 230000003647 oxidation Effects 0.000 description 4
- 238000007254 oxidation reaction Methods 0.000 description 4
- 239000000243 solution Substances 0.000 description 4
- DKGAVHZHDRPRBM-UHFFFAOYSA-N Tert-Butanol Chemical compound CC(C)(C)O DKGAVHZHDRPRBM-UHFFFAOYSA-N 0.000 description 3
- YXFVVABEGXRONW-UHFFFAOYSA-N Toluene Chemical compound CC1=CC=CC=C1 YXFVVABEGXRONW-UHFFFAOYSA-N 0.000 description 3
- 230000003197 catalytic effect Effects 0.000 description 3
- 238000007796 conventional method Methods 0.000 description 3
- 239000000284 extract Substances 0.000 description 3
- 239000000203 mixture Substances 0.000 description 3
- 238000010992 reflux Methods 0.000 description 3
- XDTMQSROBMDMFD-UHFFFAOYSA-N Cyclohexane Chemical compound C1CCCCC1 XDTMQSROBMDMFD-UHFFFAOYSA-N 0.000 description 2
- YNQLUTRBYVCPMQ-UHFFFAOYSA-N Ethylbenzene Chemical compound CCC1=CC=CC=C1 YNQLUTRBYVCPMQ-UHFFFAOYSA-N 0.000 description 2
- VQTUBCCKSQIDNK-UHFFFAOYSA-N Isobutene Chemical group CC(C)=C VQTUBCCKSQIDNK-UHFFFAOYSA-N 0.000 description 2
- OFBQJSOFQDEBGM-UHFFFAOYSA-N Pentane Chemical compound CCCCC OFBQJSOFQDEBGM-UHFFFAOYSA-N 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- TVMXDCGIABBOFY-UHFFFAOYSA-N octane Chemical compound CCCCCCCC TVMXDCGIABBOFY-UHFFFAOYSA-N 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- VVQNEPGJFQJSBK-UHFFFAOYSA-N Methyl methacrylate Chemical compound COC(=O)C(C)=C VVQNEPGJFQJSBK-UHFFFAOYSA-N 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 150000007513 acids Chemical class 0.000 description 1
- 150000001299 aldehydes Chemical class 0.000 description 1
- 239000006227 byproduct Substances 0.000 description 1
- 239000003054 catalyst Substances 0.000 description 1
- 239000007795 chemical reaction product Substances 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- JMMWKPVZQRWMSS-UHFFFAOYSA-N isopropanol acetate Natural products CC(C)OC(C)=O JMMWKPVZQRWMSS-UHFFFAOYSA-N 0.000 description 1
- 229940011051 isopropyl acetate Drugs 0.000 description 1
- GWYFCOCPABKNJV-UHFFFAOYSA-N isovaleric acid Chemical compound CC(C)CC(O)=O GWYFCOCPABKNJV-UHFFFAOYSA-N 0.000 description 1
- 239000000047 product Substances 0.000 description 1
- 238000000746 purification Methods 0.000 description 1
- 238000001577 simple distillation Methods 0.000 description 1
- -1 so in such a case Chemical compound 0.000 description 1
- 238000000638 solvent extraction Methods 0.000 description 1
- 238000004065 wastewater treatment Methods 0.000 description 1
Landscapes
- 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を含有する水性混合物か
らメタクリル酸を分離精製する方法に関するもの
である。DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for separating and purifying methacrylic acid from an aqueous mixture containing methacrylic acid.
メタクリル酸の製造法、例えば、イソブチレ
ン、第３級ブタノール、メタクロレインあるいは
イソブチルアルデヒドの接触空気酸化によるメタ
クリル酸の製造法においては、主生成物のメタク
リル酸と共に種々の副生物、とりわけ酢酸、アク
リル酸、プロピオン酸、イソ酪酸等の脂肪族カル
ボン酸が多く生成する。
In the production of methacrylic acid, for example, by catalytic air oxidation of isobutylene, tertiary butanol, methacrolein or isobutyraldehyde, various by-products, especially acetic acid and acrylic acid, are produced along with the main product methacrylic acid. , propionic acid, isobutyric acid, and other aliphatic carboxylic acids are produced in large quantities.
粗メタクリル酸は反応生成ガスの凝縮により、
これらの混合物の水溶液として得られるのが一般
的である。このメタクリル酸水溶液を直接蒸留し
てメタクリル酸を精製することは、水がメタクリ
ル酸より沸点が低いために、水の全量を留去する
ことが必要であり、エネルギーコストが嵩む上
に、分離効率が悪いので、通常はメタクリル酸を
適当な抽剤で抽出し、その後、抽剤とメタクリル
酸を分離する方法が採られる。特に抽出操作によ
つて抽出層にメタクリル酸が、水層に酢酸および
アクリル酸が移行するような抽剤としてシクロヘ
キサン又はｎ−ヘキサンを選定した提案（特公昭
56−52007号）がある。しかしながら、単なる抽
出処理だけではアクリル酸等の不純物を市場のニ
ーズに対応したレベルに下げることができないの
で、一段と純度を高める必要がある。又抽出後、
抽剤の回収、メタクリル酸の蒸留分離等の精製工
程を経てメタクリル酸が精製されることも既に周
知となつている。しかし上記不純物酸類はメタク
リル酸と沸点が比較的近かつたり、気相会合など
の影響があるので、完全に除去することは困難で
あつた。 Crude methacrylic acid is produced by condensing the reaction product gas.
Generally, these mixtures are obtained as an aqueous solution. Purifying methacrylic acid by directly distilling this aqueous methacrylic acid solution requires distilling off the entire amount of water, as water has a lower boiling point than methacrylic acid, which not only increases energy costs but also reduces separation efficiency. Since the methacrylic acid is poor, a method is usually adopted in which methacrylic acid is extracted with a suitable extractant and then the extractant and methacrylic acid are separated. In particular, a proposal was made to select cyclohexane or n-hexane as the extractant so that methacrylic acid would be transferred to the extraction layer and acetic acid and acrylic acid would be transferred to the aqueous layer during the extraction operation (Tokuko Showa).
56-52007). However, it is not possible to reduce impurities such as acrylic acid to a level that meets market needs through simple extraction treatment, so it is necessary to further increase the purity. Also, after extraction,
It is already well known that methacrylic acid is purified through purification steps such as recovery of extractant and distillation separation of methacrylic acid. However, it has been difficult to completely remove the above-mentioned impurity acids because their boiling points are relatively close to that of methacrylic acid and they are affected by gas phase association.
本発明の目的は、従来の技術において分離不充
分であつたプロピオン酸、アクリル酸およびイソ
酪酸等の低級脂肪族カルボン酸不純物を効率よく
分離するメタクリル酸の精製方法を提供すること
にある。
An object of the present invention is to provide a method for purifying methacrylic acid that efficiently separates lower aliphatic carboxylic acid impurities such as propionic acid, acrylic acid, and isobutyric acid, which have been insufficiently separated using conventional techniques.
本発明者らはこの点に着目し鋭意検討を加えた
結果、抽出溶剤とメタクリル酸を蒸留分離する際
に、アクリル酸、プロピオン酸及びイソ酪酸が溶
剤分離塔内に蓄積してくることを突き止め、これ
をサイドカツトして別途蒸留分離することでアク
リル酸、プロピオン酸及びイソ酪酸を実質上害の
ないレベルまで効率よく除去できることを見い出
し本発明を完成した。
The inventors of the present invention focused on this point and conducted extensive research, and as a result, discovered that acrylic acid, propionic acid, and isobutyric acid accumulate in the solvent separation column when the extraction solvent and methacrylic acid are separated by distillation. The present invention has been completed by discovering that acrylic acid, propionic acid and isobutyric acid can be efficiently removed to a substantially harmless level by side-cutting and separately distilling this.
即ち、本発明はプロピオン酸、アクリル酸およ
びイソ酪酸等の低級脂肪族カルボン酸を含むメタ
クリル酸水溶液から溶剤でメタクリル酸を抽出し
て後、溶剤を該メタクリル酸から分離回収し、缶
出液として得られる粗メタクリル酸を蒸留精製す
るに当つて、抽出溶剤をメタクリル酸から蒸留分
離するための溶剤分離塔の濃縮部中段から前記低
級脂肪族カルボン酸類をサイドカツトし、このサ
イドカツト液を低沸分離塔に供給して塔頂より濃
縮された該低級脂肪族カルボン酸類を分離除去
し、一方メタクリル酸を主体とする低沸分離塔缶
出液を前記溶剤分離塔回収部上段にリサイクルす
ることを特徴とするメタクリル酸の精製法を提供
するものである。 That is, the present invention extracts methacrylic acid with a solvent from an aqueous methacrylic acid solution containing lower aliphatic carboxylic acids such as propionic acid, acrylic acid, and isobutyric acid, and then separates and recovers the solvent from the methacrylic acid to produce a bottom liquid. In distilling and purifying the obtained crude methacrylic acid, the lower aliphatic carboxylic acids are side-cut from the middle stage of the concentration section of the solvent separation column for distilling and separating the extraction solvent from the methacrylic acid, and this side-cut liquid is transferred to the low-boiling separation column. The lower aliphatic carboxylic acids concentrated from the top of the column are separated and removed, while the low-boiling separation column bottoms mainly containing methacrylic acid are recycled to the upper stage of the solvent separation column recovery section. The present invention provides a method for purifying methacrylic acid.
以下本発明をさらに詳しく説明する。 The present invention will be explained in more detail below.
本発明におけるメタクリル酸水溶液としては、
プロピオン酸、アクリル酸及びイソ酪酸等の低級
脂肪族カルボン酸を含むものであれば、その製造
法に制約はないが、通常はイソブチレン、第３級
ブタノール、メタクロレインあるいはイソブチル
アルデヒドを１段ないしは２段の触媒層を通して
接触酸化として得られたものが使用される。例え
ば第３級ブタノールを２段で接触酸化して得られ
たメタクリル酸の水溶液はメタクリル酸31.5％、
酢酸4.0％、プロピオン酸0.2％、アクリル酸0.7
％、イソ酪酸0.1％、その他水及び低沸点成分と
高沸点成分とからなる。 The methacrylic acid aqueous solution in the present invention includes:
There are no restrictions on the manufacturing method as long as it contains lower aliphatic carboxylic acids such as propionic acid, acrylic acid, and isobutyric acid, but usually isobutylene, tertiary butanol, methacrolein, or isobutyraldehyde is used in one or two stages. The resulting catalytic oxidation through the stage catalyst layer is used. For example, an aqueous solution of methacrylic acid obtained by catalytic oxidation of tertiary butanol in two stages has 31.5% methacrylic acid.
Acetic acid 4.0%, propionic acid 0.2%, acrylic acid 0.7
%, isobutyric acid 0.1%, other water, low boiling point components and high boiling point components.
抽出溶剤としてはメタクリル酸の抽剤として公
知のものが使用可能であり、ｎ−ペンタン、ｎ−
ヘキサン、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、酢酸イソ
プリピル、メタクリル酸メチルなどがある。 As the extraction solvent, those known as extractants for methacrylic acid can be used, such as n-pentane, n-
Examples include hexane, n-heptane, n-octane, cyclohexane, toluene, ethylbenzene, isopropyl acetate, and methyl methacrylate.
以下図面に従つて、本発明の一実施態様を説明
する。 An embodiment of the present invention will be described below with reference to the drawings.
第１図において管１よりメタクリル酸水溶液
を、また管２より抽出溶剤を抽出塔Ａに供給して
向流接触させてメタクリル酸を抽出する。管３か
らは抽残液が排出され、場合によつてはこの中に
溶け込んだ溶剤を蒸留回収して後、廃水処理又は
焼却処理に掛けられる。 In FIG. 1, an aqueous methacrylic acid solution is supplied from tube 1 and an extraction solvent is supplied from tube 2 to extraction column A, and methacrylic acid is extracted by countercurrent contact. A raffinate is discharged from the pipe 3, and, if necessary, the solvent dissolved therein is recovered by distillation and then subjected to wastewater treatment or incineration.
メタクリル酸及び低級脂肪族カルボン酸等を含
む抽出液は管４から抜き出され溶剤分離塔Ｂに供
給される。通常カルボン酸類より沸点の低い溶剤
が抽出溶剤として使用されるので、抽出溶剤は溶
剤分離塔Ｂの塔頂から管５を経て分離回収され
る。この時酢酸は溶剤と共に塔頂より抜き出され
デカンターＣで水層側に分離されるので管７より
抜き出し排棄されるか、第２段酸化工程における
未反応メタクロレインの吸収溶剤に供される。ま
たデカンターＣの油層は一部が管６から溶剤分離
塔Ｂ塔頂へ還流され、残りは管８を通して酢酸回
収塔Ｅへ供給される。 The extract containing methacrylic acid, lower aliphatic carboxylic acids, etc. is extracted from the pipe 4 and supplied to the solvent separation column B. Since a solvent having a boiling point lower than that of the carboxylic acids is usually used as the extraction solvent, the extraction solvent is separated and recovered from the top of the solvent separation column B via the pipe 5. At this time, acetic acid is extracted from the top of the column along with the solvent and separated into the aqueous layer by decanter C, which is then extracted from pipe 7 and disposed of, or used as an absorption solvent for unreacted methacrolein in the second oxidation step. . Further, part of the oil layer in the decanter C is refluxed to the top of the solvent separation column B through a pipe 6, and the rest is supplied to the acetic acid recovery column E through a pipe 8.
溶剤分離塔Ｂの濃縮部に蓄積された低級脂肪族
カルボン酸類は濃縮部中段９から抜き出され、管
１４を経て低沸分離塔Ｄに供給される。低沸分離
塔Ｄの塔頂から管１２を経て濃縮されたプロピオ
ン酸、アクリル酸およびイソ酪酸が留出される。
一方、低級脂肪族カルボン酸濃度の下がつた缶出
液は管１１を経て溶剤分離塔Ｂの回収部上段にリ
サイクルされる。 The lower aliphatic carboxylic acids accumulated in the concentration section of the solvent separation column B are extracted from the middle stage 9 of the concentration section and supplied to the low boiling point separation column D via the pipe 14. Concentrated propionic acid, acrylic acid and isobutyric acid are distilled from the top of the low-boiling separation column D via a pipe 12.
On the other hand, the bottoms whose concentration of lower aliphatic carboxylic acids has decreased is recycled to the upper stage of the recovery section of the solvent separation column B via the pipe 11.
溶剤分離塔Ｂの塔底からはもはや該低級脂肪族
カルボン酸の含量が実用上差し支えのない濃度以
下となつたメタクリル酸が、管１０を経て取り出
される。このメタクリル酸を通常の方法で蒸留し
て高沸点成分を除去すれば市場ニーズに対応した
高純度の精製メタクリル酸を得ることができる。 From the bottom of the solvent separation column B, methacrylic acid whose content of the lower aliphatic carboxylic acid has dropped below a practically acceptable concentration is taken out via a pipe 10. By distilling this methacrylic acid using a conventional method to remove high-boiling components, highly purified purified methacrylic acid that meets market needs can be obtained.
酢酸回収塔Ｅへ供給されたデカンターＣの油層
からは溶剤に混入している酢酸が分離され、溶剤
は管２から抽出塔Ａへリサイクルされる。一方、
酢酸は塔底の管１３から排出され、管７の酢酸と
同様メタクロレインの吸収に使用される。但し使
う溶剤の種類によつては酢酸と２成分共沸を形成
することもあるので、かかる場合には塔頂から酢
酸が溶剤と共沸で抜き出され、塔底から溶剤が回
収される。 Acetic acid mixed in the solvent is separated from the oil layer in the decanter C supplied to the acetic acid recovery tower E, and the solvent is recycled to the extraction tower A through the pipe 2. on the other hand,
The acetic acid is discharged through tube 13 at the bottom of the column and, like the acetic acid in tube 7, is used to absorb methacrolein. However, depending on the type of solvent used, it may form a two-component azeotrope with acetic acid, so in such a case, acetic acid is extracted azeotropically with the solvent from the top of the column, and the solvent is recovered from the bottom of the column.
以下に実施例を示して本発明を具体的に説明す
る。
EXAMPLES The present invention will be specifically described below with reference to Examples.
実施例 １
メタクリル酸21.0部、酢酸4.2部、プロピオン
酸0.05部、アクリル酸0.5部、イソ酪酸0.04部、ア
ルデヒド類0.5部、その他少量の高沸点物を含む
メタクリル酸の水溶液を、メタクリル酸抽出塔Ａ
（塔径75mm、円板数70枚の回転円板塔）の上部へ
2.8Kg／Hrの速度で供給し、塔底からはヘプタン
を3.0Kg／Hrで供給してメタクリル酸の抽出を行
つた。各酸の抽出はメタクリル酸、プロピオン
酸、アクリル酸およびイソ酪酸が99.2％、酢酸
18.7％であつた。このメタクリル酸抽出液は3.4
Kg／Hrの供給速度で溶剤分離塔Ｂ（塔径70mm、段
数30段の多孔板塔）に送入した。操作条件60mm
Hg絶対圧、塔頂28℃、塔底95℃で還流比2.5とし
塔頂からヘプタンと水を回収し、デカンターＣで
水層を分離した後、酢酸分離塔Ｅで酢酸を除去
し、抽出塔Ａへリサイクルした。一方、溶剤分離
塔Ｂの濃縮部中段からは還流比10で、プロピオン
酸4.4部、アクリル酸34.6部、イソ酪酸9.4部、メ
タクリル酸50.9部、水0.7部からなる成分を0.2
Kg／Hrでサイドカツトし、低沸分離塔Ｄへ供給
した。低沸分離塔Ｄでは、操作圧力50mmHg（絶対
圧）、塔頂温度75℃、塔底温度91.2℃で操作し、
還流比５で塔頂よりプロピオン酸8.8部、アクリ
ル酸67.2部、イソ酪酸18.8部、水1.4部およびメタ
クリル酸1.8部からなる留出液を0.017Kg／Hrで抜
き出した。塔底からはメタクリル酸95.3部、プロ
ピオン酸0.5部、アクリル酸3.1部、イソ酪酸0.7部
からなる缶出液0.18Kg／Hrを得た。この缶出液
は溶剤分離塔Ｂ回収部上段へリサイクルした。ま
た溶剤分離塔Ｂの塔底からはメタクリル酸99.9
部、プロピオン酸3ppm、アクリル酸6ppm、イソ
酪酸12ppm、高沸点物0.1部のメタクリル酸0.59
Kg／Hrを得た。Example 1 An aqueous solution of methacrylic acid containing 21.0 parts of methacrylic acid, 4.2 parts of acetic acid, 0.05 parts of propionic acid, 0.5 parts of acrylic acid, 0.04 parts of isobutyric acid, 0.5 parts of aldehydes, and a small amount of other high-boiling substances was added to a methacrylic acid extraction column. A
(to the top of the rotating disk tower with a tower diameter of 75 mm and 70 disks)
Methacrylic acid was extracted by feeding at a rate of 2.8 Kg/Hr, and heptane was fed from the bottom of the column at a rate of 3.0 Kg/Hr. Extraction of each acid is 99.2% methacrylic acid, propionic acid, acrylic acid and isobutyric acid, and acetic acid
It was 18.7%. This methacrylic acid extract is 3.4
The solution was fed into the solvent separation column B (a perforated plate column with a column diameter of 70 mm and 30 plates) at a feed rate of Kg/Hr. Operating conditions 60mm
Hg absolute pressure, column top 28℃, column bottom 95℃, reflux ratio 2.5, heptane and water are recovered from the column top, the aqueous layer is separated in decanter C, acetic acid is removed in acetic acid separation column E, and extraction column Recycled to A. On the other hand, from the middle stage of the concentration section of the solvent separation column B, a component consisting of 4.4 parts of propionic acid, 34.6 parts of acrylic acid, 9.4 parts of isobutyric acid, 50.9 parts of methacrylic acid, and 0.7 parts of water was collected at a reflux ratio of 0.2 parts.
It was side cut at Kg/Hr and fed to low boiling point separation column D. The low-boiling separation column D was operated at an operating pressure of 50 mmHg (absolute pressure), a column top temperature of 75 °C, and a column bottom temperature of 91.2 °C.
At a reflux ratio of 5, a distillate consisting of 8.8 parts of propionic acid, 67.2 parts of acrylic acid, 18.8 parts of isobutyric acid, 1.4 parts of water, and 1.8 parts of methacrylic acid was extracted from the top of the column at a rate of 0.017 Kg/Hr. From the bottom of the column, 0.18 kg/hr of bottoms was obtained consisting of 95.3 parts of methacrylic acid, 0.5 parts of propionic acid, 3.1 parts of acrylic acid, and 0.7 parts of isobutyric acid. This bottoms was recycled to the upper stage of the recovery section of the solvent separation column B. In addition, 99.9% of methacrylic acid was extracted from the bottom of solvent separation column B.
parts, propionic acid 3ppm, acrylic acid 6ppm, isobutyric acid 12ppm, high boilers 0.1 part methacrylic acid 0.59
Kg/Hr was obtained.
比較例 １
実施例１と同様の方法で溶剤分離塔Ｂで低級脂
肪族カルボン酸をサイドカツトすることなくメタ
クリル酸の精製を行つたところ、溶剤分離塔Ｂの
塔底から得られた液組成はメタクリル酸97.2部、
プロピオン酸0.2部、アクリル酸2.3部、イソ酪酸
0.2部、その他水及び高沸点物0.1部であつた。こ
れを常法に従い低沸分離塔及び高沸分離塔に掛け
精製したが得られたメタクリル酸の純度は99.8％
であつたがプロピオン酸30ppm、アクリル酸
75ppm、イソ酪酸180ppmを含んでいた。Comparative Example 1 When methacrylic acid was purified in the same manner as in Example 1 in solvent separation column B without side-cutting lower aliphatic carboxylic acids, the liquid composition obtained from the bottom of solvent separation column B was methacrylic acid. 97.2 parts of acid,
0.2 parts of propionic acid, 2.3 parts of acrylic acid, isobutyric acid
0.2 part, and 0.1 part of other water and high boiling point substances. This was purified by applying it to a low-boiling separation column and a high-boiling separation column according to the conventional method, and the purity of the obtained methacrylic acid was 99.8%.
Atsutaga propionic acid 30ppm, acrylic acid
It contained 75 ppm and 180 ppm of isobutyric acid.
本発明によれば、プロピオン酸、アクリル酸お
よびイソ酪酸等の低級脂肪族カルボン酸を不純物
として含むメタクリル酸の水溶液を溶剤抽出の
後、蒸留してメタクリル酸を精製する際に、溶剤
分離塔内に蓄積する低級脂肪族カルボン酸をサイ
ドカツトし、低沸分離塔で留去し塔底液は溶剤分
離塔へリサイクルすることにより、従来技術の如
き単純な蒸留では十分に分離除去することが困難
であつた該低級脂肪族カルボン酸を効率よく除去
し、高品位のメタクリル酸を容易に得ることが可
能となつた。
According to the present invention, when purifying methacrylic acid by solvent extraction and distillation of an aqueous solution of methacrylic acid containing lower aliphatic carboxylic acids such as propionic acid, acrylic acid, and isobutyric acid as impurities, By side-cutting the lower aliphatic carboxylic acids that accumulate in the solvent, distilling them off in a low-boiling separation column, and recycling the bottom liquid to a solvent separation column, it is difficult to separate and remove them sufficiently with simple distillation as in the conventional technology. It became possible to efficiently remove the hot lower aliphatic carboxylic acid and easily obtain high-grade methacrylic acid.
第１図は、本発明の一実施態様を説明するため
のフローシートである。
Ａ……抽出塔、Ｂ……溶剤分離塔、Ｃ……デカ
ンター、Ｄ……低沸分離塔、Ｅ……酢酸分離塔。
FIG. 1 is a flow sheet for explaining one embodiment of the present invention. A...extraction tower, B...solvent separation tower, C...decanter, D...low boiling point separation tower, E...acetic acid separation tower.
Claims (1)
の低級脂肪族カルボン酸を含むメタクリル酸水溶
液から溶剤でメタクリル酸を抽出して後、溶剤を
該メタクリル酸から分離回収し、缶出液として得
られる粗メタクリル酸を蒸留精製するに当つて、
抽出溶剤をメタクリル酸から蒸留分離するための
溶剤分離塔の濃縮部中段から前記低級脂肪族カル
ボン酸類をサイドカツトし、このサイドカツト液
を低沸分離塔に供給して塔頂より濃縮された前記
低級脂肪族カルボン酸類を分離除去し、一方メタ
クリル酸を主体とする低沸分離塔缶出液を前記溶
剤分離塔回収部上段にリサイクルすることを特徴
とするメタクリル酸の精製方法。1. After extracting methacrylic acid with a solvent from an aqueous methacrylic acid solution containing lower aliphatic carboxylic acids such as propionic acid, acrylic acid, and isobutyric acid, the solvent is separated and recovered from the methacrylic acid, and crude methacrylic acid is obtained as a bottom liquid. In purifying acid by distillation,
The lower aliphatic carboxylic acids are side-cut from the middle stage of the concentration section of the solvent separation column for distilling and separating the extraction solvent from methacrylic acid, and this side-cut liquid is supplied to the low-boiling separation column, where the lower fat is concentrated from the top of the column. A method for purifying methacrylic acid, which comprises separating and removing group carboxylic acids, and recycling a low-boiling separation column bottoms mainly composed of methacrylic acid to the upper stage of the solvent separation column recovery section.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP28438885A JPS62145044A (en) | 1985-12-19 | 1985-12-19 | Purification of methacrylic acid |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP28438885A JPS62145044A (en) | 1985-12-19 | 1985-12-19 | Purification of methacrylic acid |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS62145044A JPS62145044A (en) | 1987-06-29 |
| JPH0580462B2 true JPH0580462B2 (en) | 1993-11-09 |
Family
ID=17677935
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP28438885A Granted JPS62145044A (en) | 1985-12-19 | 1985-12-19 | Purification of methacrylic acid |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS62145044A (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5523480A (en) * | 1994-03-28 | 1996-06-04 | Rohm And Haas Company | Process for purifying unsaturated carboxylic acids using distillation and melt crystallization |
-
1985
- 1985-12-19 JP JP28438885A patent/JPS62145044A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS62145044A (en) | 1987-06-29 |
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