JPS6115057B2 - - Google Patents

Info

Publication number
JPS6115057B2
JPS6115057B2 JP52087990A JP8799077A JPS6115057B2 JP S6115057 B2 JPS6115057 B2 JP S6115057B2 JP 52087990 A JP52087990 A JP 52087990A JP 8799077 A JP8799077 A JP 8799077A JP S6115057 B2 JPS6115057 B2 JP S6115057B2
Authority
JP
Japan
Prior art keywords
methacrylic acid
methyl methacrylate
water
methanol
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
Application number
JP52087990A
Other languages
Japanese (ja)
Other versions
JPS5424813A (en
Inventor
Tatsuro Masuko
Shigeo Fukaya
Kazuhiko Masaoka
Yasuo Takeuchi
Takashi Uchida
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.)
Mitsubishi Kasei Corp
Original Assignee
Mitsubishi Kasei Corp
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 Mitsubishi Kasei Corp filed Critical Mitsubishi Kasei Corp
Priority to JP8799077A priority Critical patent/JPS5424813A/en
Priority to NL7807420A priority patent/NL7807420A/en
Priority to CS464278A priority patent/CS214895B2/en
Priority to GB7830309A priority patent/GB2001315B/en
Priority to FR7821746A priority patent/FR2398037A1/en
Priority to DE19782832202 priority patent/DE2832202A1/en
Publication of JPS5424813A publication Critical patent/JPS5424813A/en
Publication of JPS6115057B2 publication Critical patent/JPS6115057B2/ja
Granted legal-status Critical Current

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

Description

【発明の詳細な説明】 本発明はメタクリル酸の分離方法に関する。さ
らに詳しくは、本発明は、水、メタノール、メタ
クリル酸及びメタクリル酸メチルを含む混合液か
らメタクリル酸を蒸留により分離する方法に関す
る。 メタクリル酸のメタノールによるエステル化反
応は平衡反応であり、得られる反応生成物は水、
メタノール、メタクリル酸及びメタクリル酸メチ
ルからなる混合物である。 このような反応生成物から目的生成物であるメ
タクリル酸メチルを分離する方法としては、抽
出、蒸留等による方法が多数知られているが、必
ずしも経済性からいつて満足すべきものではな
い。 そして、このような場合、エステル化反応生成
物中のメタクリル酸の存在が、メタクリル酸メチ
ルの分離操作を煩雑、経済的不利にしている例が
少なくない。たとえば、エステル化反応生成物を
有機溶媒と水で液相抽出し、メタクリル酸メチル
を有機相へ、メタノールを水相へと分離するよう
な場合、メタクリル酸は水に溶解しやすいため水
相側に含まれるが、この水溶液から希薄なメタク
リル酸を回収するのは困難であり、またこれを廃
棄するにしても、生物学的方法によるメタクリル
酸の分解無毒化がが要求され、経済的に極めて不
利である。また、メタクリル酸は重合しやすいの
で、エステル化反応生成物を蒸留してメタクリル
酸メチルを分離するような場合にはメタクリル酸
が重合して不都合をひきおこすこともある。 したがつて、上記エステル化反応生成物からメ
タクリル酸メチルを分離するに先立つて、メタク
リル酸を分離除去しておくことが望ましい。 本発明の目的は水、メタノール、メタクリル酸
及びメタクリル酸メチルを含む混合液からメタク
リル酸を効率良くかつ高い選択性をもつて分離す
る方法を提供することにあり、この目的は、本発
明方法に従つて、水、メタノール、メタクリル酸
及びメタクリル酸メチルを含む混合液を、蒸留系
内に水が存在する期間中、蒸留系内にメタクリル
酸メチルが存在するように蒸留系を維持しつつ蒸
留して、塔頂から実質的に全量の水、メタノール
及びメタクリル酸メチルを留出させ、塔底から実
質的に全量のメタクリル酸を抜き出すことによつ
てメタクリル酸を分離することにより達成され
る。 本発明を詳細に説明すると、本発明方法に従つ
て、水、メタノール、メタクリル酸及びメタクリ
ル酸メチルを含む混合液(たとえば、メタクリル
酸のメタノールによるエステル化反応生成物)を
蒸留して塔頂から実質的に全量の水、メタノール
及びメタクリル酸メチルを留出させ塔底から実質
的に全量のメタクリル酸を抜き出すには、上記混
合液中に含まれる水がメタクリル酸メチルとの共
沸蒸留によつて塔頂から実質的に留去されるに十
分な量のメタクリル酸メチルが上記混合液中に含
まれることが必要である。水をメタクリル酸メチ
ルとの共沸蒸留によつて塔頂から実質的に留去さ
れるに十分な量のメタクリル酸メチルが存在しな
い場合には、メタクリル酸が水との共沸により塔
頂から留去するので、留出物中にメタクリル酸が
含まれる。 なお、上記混合液中に含まれる水をメタクリル
酸メチルとの共沸蒸留によつて塔頂から実質的に
留去させるに十分なメタクリル酸メチルの量は、
混合液中の水及びメタノールの量がわかれば、操
作圧力下での水−メタクリル酸メチル及びメタノ
ール−メタクリル酸メチルの各共沸混合物の組成
に基いて計算することができる。すなわち、メタ
クリル酸メチルは水と同様メタノールとも共沸す
るので、混合液中の水及びメタノールの実質的に
全量をメタクリル酸メチルとの共沸蒸留により塔
頂から留出させるに必要な量のメタクリル酸メチ
ルが存在すればよい。 メタクリル酸メチルが不足する場合には、留出
物の油相を還流することによりメタクリル酸メチ
ルを補充すればよい。この場合の還流量は必要に
応じて適宜選択すればよいが、通常、還流比は0
〜0.5の範囲から選ばれる。 上記した蒸留は、通常の蒸留塔を使用し、常法
に従つて行なわれる。蒸留は通常、常圧又は減圧
下に行なわれるが、メタクリル酸及びメタクリル
酸メチルの重合を防止するために減圧下低温で行
なうのが望ましい。 以上のようにして蒸留を行なうことにより、塔
底からは、実質的に全量のメタクリル酸が、他成
分をほとんど含まない状態で得られる。なお、塔
頂からも蒸気圧分に相当する程度の量のメタクリ
ル酸が留出するが、これはメタクリル酸の全体の
量からみれば無視できる程度である。 このようにして塔底から得られるメタクリル酸
は回収され、必要に応じて精製あるいはエステル
化反応の原料として再使用される。 塔頂からの留出物である、実質的にメタクリル
酸を含まない、メタクリル酸メチル、水及びメタ
ノールからなる混合液からは、溶媒抽出、蒸留等
の方法により、比較的容易にメタクリル酸メチル
を分離することができる。 以上述べたように、本発明方法によれば、水、
メタノール、メタクリル酸及びメタクリル酸メチ
ルを含む混合液からのメタクリル酸の分離を、簡
易かつ経済的有利に行なうことができる。 次に、実施例により本発明方法をさらに具体的
に説明するが、本発明はその要旨を超えない限
り、以下の実施例に限定されない。 実施例 内径32mm、段数24段のオルダーシヨー型蒸留塔
の中段に、下記表に示す組成の原料混合液(38
℃)を供給し、塔頂圧力115Torr、塔底温度110
℃、塔頂温度37℃の条件で蒸留を行なつた。留出
物は冷却後2液相に分液するので、その油相を、
還流比0.1で還流させた。このようにして得られ
た留出液及び缶出液の組成を下記表に示す。 【表】
DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for separating methacrylic acid. More specifically, the present invention relates to a method for separating methacrylic acid from a liquid mixture containing water, methanol, methacrylic acid, and methyl methacrylate by distillation. The esterification reaction of methacrylic acid with methanol is an equilibrium reaction, and the resulting reaction products are water,
It is a mixture consisting of methanol, methacrylic acid and methyl methacrylate. Many methods such as extraction and distillation are known as methods for separating the desired product, methyl methacrylate, from such reaction products, but these methods are not necessarily satisfactory from an economic standpoint. In such cases, the presence of methacrylic acid in the esterification reaction product often makes the separation operation of methyl methacrylate complicated and economically disadvantageous. For example, when performing liquid phase extraction of the esterification reaction product with an organic solvent and water and separating methyl methacrylate into the organic phase and methanol into the aqueous phase, methacrylic acid is easily dissolved in water, so the aqueous phase However, it is difficult to recover dilute methacrylic acid from this aqueous solution, and even if it is to be disposed of, decomposition and detoxification of methacrylic acid using biological methods is required, making it economically extremely difficult. It is disadvantageous. Furthermore, since methacrylic acid is easily polymerized, when the esterification reaction product is distilled to separate methyl methacrylate, the methacrylic acid may polymerize and cause problems. Therefore, it is desirable to separate and remove methacrylic acid before separating methyl methacrylate from the esterification reaction product. An object of the present invention is to provide a method for efficiently and highly selectively separating methacrylic acid from a mixed liquid containing water, methanol, methacrylic acid, and methyl methacrylate; Therefore, a mixture containing water, methanol, methacrylic acid and methyl methacrylate is distilled while maintaining the distillation system such that methyl methacrylate is present in the distillation system during the period in which water is present in the distillation system. This is achieved by separating methacrylic acid by distilling off substantially all of the water, methanol and methyl methacrylate from the top of the column, and extracting substantially all of the methacrylic acid from the bottom of the column. To explain the present invention in detail, according to the method of the present invention, a mixed liquid containing water, methanol, methacrylic acid, and methyl methacrylate (for example, a reaction product of esterification of methacrylic acid with methanol) is distilled from the top of the column. In order to distill out substantially all of the water, methanol and methyl methacrylate and to extract substantially all of the methacrylic acid from the bottom of the column, the water contained in the above liquid mixture is distilled by azeotropic distillation with methyl methacrylate. It is necessary that a sufficient amount of methyl methacrylate be contained in the mixture so that it can be substantially distilled off from the top of the column. If a sufficient amount of methyl methacrylate is not present for water to be substantially removed from the top by azeotropic distillation with methyl methacrylate, methacrylic acid is removed from the top by azeotropic distillation with water. Since it is distilled off, methacrylic acid is contained in the distillate. The amount of methyl methacrylate that is sufficient to substantially distill off the water contained in the liquid mixture from the top of the column by azeotropic distillation with methyl methacrylate is as follows:
Once the amounts of water and methanol in the mixture are known, calculations can be made based on the composition of the water-methyl methacrylate and methanol-methyl methacrylate azeotropes under operating pressure. In other words, since methyl methacrylate azeotropes with methanol as well as water, the amount of methacrylate necessary to distill substantially all of the water and methanol in the mixture from the top of the column by azeotropic distillation with methyl methacrylate. The presence of methyl acid is sufficient. If methyl methacrylate is insufficient, methyl methacrylate may be replenished by refluxing the oil phase of the distillate. In this case, the reflux amount may be selected as appropriate, but the reflux ratio is usually 0.
Selected from the range ~0.5. The above-mentioned distillation is carried out in a conventional manner using a conventional distillation column. Distillation is usually carried out under normal pressure or reduced pressure, but preferably carried out at reduced pressure and low temperature in order to prevent polymerization of methacrylic acid and methyl methacrylate. By carrying out the distillation as described above, substantially the entire amount of methacrylic acid is obtained from the bottom of the column in a state containing almost no other components. Although methacrylic acid is distilled from the top of the column in an amount corresponding to the vapor pressure, this is negligible in terms of the total amount of methacrylic acid. The methacrylic acid thus obtained from the bottom of the column is recovered and reused as a raw material for purification or esterification reaction, if necessary. Methyl methacrylate can be relatively easily extracted from a mixture of methyl methacrylate, water and methanol, which is a distillate from the top of the tower and which does not substantially contain methacrylic acid, by methods such as solvent extraction and distillation. Can be separated. As described above, according to the method of the present invention, water,
Separation of methacrylic acid from a mixed solution containing methanol, methacrylic acid, and methyl methacrylate can be performed easily and economically. Next, the method of the present invention will be explained in more detail with reference to Examples, but the present invention is not limited to the following Examples unless the gist thereof is exceeded. Example A raw material mixture (38
°C), top pressure 115 Torr, bottom temperature 110
Distillation was carried out under conditions of 37°C and a column top temperature of 37°C. The distillate is separated into two liquid phases after cooling, so the oil phase is
It was refluxed at a reflux ratio of 0.1. The compositions of the distillate and bottoms thus obtained are shown in the table below. 【table】

Claims (1)

【特許請求の範囲】 1 水、メタノール、メタクリル酸及びメタクリ
ル酸メチルを含む混合液を、蒸留系内に水が存在
する期間中、蒸留系内にメタクリル酸メチルが存
在するように蒸留系を維持しつつ蒸留して、塔頂
から実質的に全量の水、メタノール及びメタクリ
ル酸メチルを留出させ、塔底から実質的に全量の
メタクリル酸を抜き出すことを特徴とするメタク
リル酸の分離方法。 2 特許請求の範囲第1項記載のメタクリル酸の
分離方法に於て、混合液に含まれる水をメタクリ
ル酸メチルとの共沸蒸留により塔頂から実質的に
留去させるに十分な量のメタクリル酸メチルが該
混合液中に含まれることを特徴とする方法。
[Claims] 1. A mixture containing water, methanol, methacrylic acid, and methyl methacrylate is maintained in the distillation system so that methyl methacrylate is present during the period when water is present in the distillation system. 1. A method for separating methacrylic acid, which comprises distilling water, methanol, and methyl methacrylate from the top of the column, and extracting substantially all of the methacrylic acid from the bottom of the column. 2. In the method for separating methacrylic acid as set forth in claim 1, a sufficient amount of methacrylic acid is used to substantially distill off water contained in the liquid mixture from the top of the column by azeotropic distillation with methyl methacrylate. A method characterized in that methyl acid is contained in the mixture.
JP8799077A 1977-07-22 1977-07-22 Separation of methacrylic acid Granted JPS5424813A (en)

Priority Applications (6)

Application Number Priority Date Filing Date Title
JP8799077A JPS5424813A (en) 1977-07-22 1977-07-22 Separation of methacrylic acid
NL7807420A NL7807420A (en) 1977-07-22 1978-07-10 PROCESS FOR THE SEPARATION OF METHACRYLIC ACID FROM A MIXTURE CONTAINING WATER, METHANOL, METHACRYLIC ACID AND METHYL METHACRYLATE.
CS464278A CS214895B2 (en) 1977-07-22 1978-07-11 Method of separation of the methacryl acid
GB7830309A GB2001315B (en) 1977-07-22 1978-07-19 Process for separating methacrylic acid from an esterification mixture
FR7821746A FR2398037A1 (en) 1977-07-22 1978-07-21 METHOD FOR SEPARATING METHACRYLIC ACID FROM AN ESTERIFICATION MIXTURE
DE19782832202 DE2832202A1 (en) 1977-07-22 1978-07-21 PROCESS FOR SEPARATION OF METHACRYLIC ACID FROM AN ESTERIFICATION MIXTURE

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP8799077A JPS5424813A (en) 1977-07-22 1977-07-22 Separation of methacrylic acid

Publications (2)

Publication Number Publication Date
JPS5424813A JPS5424813A (en) 1979-02-24
JPS6115057B2 true JPS6115057B2 (en) 1986-04-22

Family

ID=13930243

Family Applications (1)

Application Number Title Priority Date Filing Date
JP8799077A Granted JPS5424813A (en) 1977-07-22 1977-07-22 Separation of methacrylic acid

Country Status (1)

Country Link
JP (1) JPS5424813A (en)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS58162105A (en) * 1982-03-23 1983-09-26 Matsushita Electric Ind Co Ltd Crystal oscillating circuit

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3639460A (en) * 1967-07-11 1972-02-01 Roehm Gmbh Esterification of methacrylic acid
JPS49124018A (en) * 1973-04-03 1974-11-27
JPS51146418A (en) * 1975-06-10 1976-12-16 Nippon Zeon Co Ltd Purification of methacrylic esters

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3639460A (en) * 1967-07-11 1972-02-01 Roehm Gmbh Esterification of methacrylic acid
JPS49124018A (en) * 1973-04-03 1974-11-27
JPS51146418A (en) * 1975-06-10 1976-12-16 Nippon Zeon Co Ltd Purification of methacrylic esters

Also Published As

Publication number Publication date
JPS5424813A (en) 1979-02-24

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