JPS5965041A - Preparation of methyl methacrylate - Google Patents

Abstract

PURPOSE:To prepare the titled compound in high yield, by amidating methacrylonitrile in the presence of sulfuric acid until the maximum amidation ratio is obtained, decreasing the amount of the unreacted raw material in the presence of a specific amount of water keeping the amidation ratio, and esterifying the product. CONSTITUTION:Methacrylonitrile is made to react with sulfuric acid and water to obtain methacrylamide, which is converted to methyl methacrylate by esterification. The above process is carried out by (1) proceeding the amidation reaction of methacrylamide in the presence of sulfuric acid until the maximum amidation ratio (preferably 96-99%) is achieved, (2) decreasing the amount of unreacted methacrylonitrile in the presence of 0.03-0.3mol of water per 1mol of the methacrylonitrile keeping the amidation ratio essentially to the above level, and (3) esterifying the product. EFFECT:The reaction proceeds under mild condition using small amount of sulfuric acid. The process is simple and economical.

Description

【発明の詳細な説明】 本発明はメタクリロニトリル（以後ＭＡＮと略記する）
から未反応ＭＡＮが数十ｐｐｍという極めて少いメタク
リル酸メチル（以後ＭＭＡと略記する）を高収率で製造
する方法に関する。Detailed Description of the Invention The present invention relates to methacrylonitrile (hereinafter abbreviated as MAN)
It relates to a method for producing methyl methacrylate (hereinafter abbreviated as MMA) in high yield with an extremely low amount of unreacted MAN of several tens of ppm.

ＭＭＡ中に未反応ＭＡＮが残存している場合はそのポリ
マーの色度や物性に悪影響を与える懸念があり、未反応
ＭＡＮは極力低減することが望ましい。If unreacted MAN remains in MMA, there is a concern that it will adversely affect the chromaticity and physical properties of the polymer, so it is desirable to reduce unreacted MAN as much as possible.

従来、不飽和二）　ＩＪルを鉱酸及び水で加水分解し、
次いでエステル化して不飽和カルボン酸エステルを製造
する方法は公知であるが、エステル中の残存二）　ＩＪ
ルについては、論じたものが少く又ｐｐｍの水準につい
て論じたものは皆無であった。Conventionally, unsaturated IJ is hydrolyzed with mineral acid and water,
A method for producing an unsaturated carboxylic acid ester by subsequent esterification is known, but the remaining 2) IJ in the ester
There were few discussions on the level of ppm, and there were no discussions on ppm levels.

未反応ニトリルを低減する一般的な方法としてエステル
化後の蒸留による分離及びアミド化反応及びエステル化
反応時の条件設定による低減が代表的なものとして上げ
られる。ところが通常の蒸留方法による精製で数百〜数
千ｐｐｍという低濃度の未反応二）　ＩＪルを分離する
には相当の困難性があり、さらにＶＡＮとそのエステル
であるＭＭＡの場合の様に沸点が近い場合には著しく困
難さなる。Typical common methods for reducing unreacted nitriles include separation by distillation after esterification and reduction by setting conditions during amidation and esterification reactions. However, it is quite difficult to separate unreacted IJ at a low concentration of several hundred to several thousand ppm by purification using ordinary distillation methods, and furthermore, as in the case of VAN and its ester MMA, the boiling point It becomes extremely difficult when the values are close to each other.

また反応による未反応ニトリルの一般的な低減方法とし
ては硫酸及び水のモル比を上げる方法、反応温度を上げ
る方法、滞留時間を増す方法が上げられる。例えば、特
公昭５２−６９７４号公報には、アクリロニトリルから
アクリルアミド硫酸塩を製造する場合における未反応ニ
ドＩＪルの低減方法として、収率低下や副生成物の増加
を招かない範囲で、化学量論量より過剰量の硫酸と水を
使用する方法が記載されており、ニトリル１モル当り硫
酸及び水のモル比は１．０〜１．３が最適だとしている
０しかしＭＡＮよりＭＭＡを製造する場合の実施例をみ
る限°す、未反応ＭＡＮは供給ＭＡＮを基に２％残存し
ており数十から数百ｐｐｍの水準については論議されて
いない。Further, general methods for reducing unreacted nitrile through reaction include increasing the molar ratio of sulfuric acid and water, increasing the reaction temperature, and increasing the residence time. For example, Japanese Patent Publication No. 52-6974 describes a method for reducing unreacted nitrogen when producing acrylamide sulfate from acrylonitrile. A method is described in which an excess amount of sulfuric acid and water is used, and the optimum molar ratio of sulfuric acid and water per mole of nitrile is 1.0 to 1.3.However, when producing MMA from MAN, As far as the examples described above are concerned, unreacted MAN remains at 2% based on the supplied MAN, and a level of several tens to hundreds of ppm is not discussed.

さらに本発明者らの検討によれば未反応ＭＡＮを極力低
減する目的で上記公報記載の条件で反応を行った所、供
給ＭＡＩＩ　１モル当りの水モル比が１．１０未満の場
合には、反応温度を高くするか又は反応時間を長くして
も１反応系内に若干水が残存するにもかかわらず未反応
ＭＡＮは１１００ｐｐ以下には低減せず、むしろアミド
化収率が低下するという問題がある事が判明した。Furthermore, according to the studies of the present inventors, when the reaction was carried out under the conditions described in the above publication for the purpose of reducing unreacted MAN as much as possible, if the molar ratio of water per 1 mole of supplied MAII was less than 1.10, Even if the reaction temperature is increased or the reaction time is increased, the unreacted MAN does not decrease to below 1100 pp even though some water remains in the reaction system, and the amidation yield actually decreases. It turns out that there is.

また王化誌６９−６　（１９６６）にはＭＡＮよりＭＭ
Ａを合成する方法に於いてＭＡＮとメタノールの混合溶
液に硫酸を滴下しメタクリル酸アミドのモノアルキル硫
酸塩とし１次いでメタノール水を加えエステル化する方
法は、硫酸水溶液にＭＡＮを滴下しメタクリルアミド硫
酸塩とし、次いでメタノールを加えエステル化を行う方
法に比べ、未反応ニドＩＪルを低減出来ると記載されて
いるが具体例によると前者の方法の場合でも未反応ＭＡ
Ｎが供給ＭＡＮを基にして約２％程度残存しており、数
十〜数百ｐｐｍの水準には低減できていない。Also, in Wangkashi 69-6 (1966), MM is better than MAN.
In the method of synthesizing A, sulfuric acid is added dropwise to a mixed solution of MAN and methanol to form a monoalkyl sulfate of methacrylic acid amide, and then methanol water is added to esterify it. It is stated that the amount of unreacted nitrogen can be reduced compared to the method of forming a salt and then adding methanol for esterification, but according to specific examples, even in the case of the former method, unreacted MA
About 2% of N remains based on the supply MAN, and it has not been possible to reduce it to a level of several tens to hundreds of ppm.

この様に収率を低下させる事なく、未反応ＭＡＮを極力
低減する工業技術は未完成である〇本発明者らは上記状
況にあるＭＡＮを原料とするＭＭＡの製造方法について
鋭意研究を重ねた結呆１ＭＡＮと硫酸及び水と反応させ
メタクリルアミド硫酸塩を製造する場合には一種の平衡
現象が有り、未反応ＭＡＮを数十ｐｐｍの水準に低減す
るには、水が極めて重要な働きをする事を見い出し本発
明に至った。さらに詳述すればＭＡＮと硫酸及び水と反
応させた場合に１反応の進行に従い最大のアミド化収率
（−アミド液中の笑測二重結合邦／供給ＭＡＮ中の理論
二重結合量）がイ（トられる時点があるが、この時点で
は未反応ＭＡＮは未だ数百〜数千ｐｐｍ残存しており品
質面の要求を満たさない０反応を続行し未反応ＭＡＮの
低減を行う場合には１本発明者らが見い出した以下のポ
イントに留意する必要がある。第一に未反応ＭＡＮの最
小到達濃度は反応生成物中の水濃度により規定される事
（第１図参照）、第二に反応温度が低い場合の方が反応
温度が高い場合に比し、未反応ＭＡＮの最小到達濃度が
低（なる傾向が見られる事（第１図参照）、第三に６ｔ
ｅ　ＭはＭＡＮに対し等モル以上存在すれば、未反応Ｍ
ＡＮの低減速度には関係するものの未反応ＶＡＮの最小
到達濃度には関係しない事（ｖＩ２図参照）のｉｉ要点
である。さらにはアミド化収率を維持するには反応温度
を而＜シない事及びＭＡＮに対する硫酸モル比を高くし
ない事への留意が必要である〇 上述の現象に対し本発明者らはＭＡＮとメタクリルアミ
ド及びメタクリル酸の間に平衡現象が起っている為と解
釈している。すなわちＭＡＮを硫酸及び水と反応させた
場合にはメタクリルアミド硫酸塩が生成するが水が理論
Ｊ１（より過剰にある場合には遂次反応によりメタクリ
ル酸が生成する。この場合にＭＡＮと硫酸及び水からメ
タクリルアミド硫酸塩が生成する速度はメタクリルアミ
ド硫酸塩と水からメタクリル酸が生成する速度に比し速
い為に、まずＭＡＮよりメタクリルアミド硫酸塩が生成
する反応が主体的に進行してＭＡＮとメタクリルアミド
硫酸塩の間が大略平衡状態となり、続いてメタクリルア
ミド硫酸塩とメタクリル酸の間が平衡状態となり、この
時点で三者間の平衡に到達するものと考えられる。この
様な平衡を考えれば１発熱反応であるＭＡＮからメタク
リルアミドが生成する反応に於いて反応温度が高い場合
に未反応ＭＡＮの水準が晶くなる現象は容易に理解され
る０ 上述の様に、未反応ＭＡＮを反応により低減する際には
、水が極めて重要な働きをするが、この水も必要量以上
に多い場合には未反応ＭＡＮの低減速度が減少し、エス
テル化した場合にはメタクリル酸の副生率が増大し、且
つメタクリル酸がＭＭＡに比し沸点が高く重合し易い為
か。In this way, the industrial technology to reduce unreacted MAN as much as possible without reducing the yield has not yet been completed. The present inventors have conducted intensive research on a method for producing MMA using MAN in the above situation as a raw material. When producing methacrylamide sulfate by reacting 1MAN with sulfuric acid and water, there is a kind of equilibrium phenomenon, and water plays an extremely important role in reducing unreacted MAN to a level of several tens of ppm. This discovery led to the present invention. More specifically, when MAN is reacted with sulfuric acid and water, the maximum amidation yield is achieved according to the progress of one reaction (-measured amount of double bonds in the amide solution/theoretical amount of double bonds in the supplied MAN) There is a point when the unreacted MAN is removed, but at this point unreacted MAN still remains in the amount of several hundred to several thousand ppm, which does not meet the quality requirements. 1 It is necessary to keep in mind the following points discovered by the present inventors: First, the minimum concentration of unreacted MAN is determined by the water concentration in the reaction product (see Figure 1); The minimum concentration of unreacted MAN is lower when the reaction temperature is lower than when the reaction temperature is high (see Figure 1). Third, 6t
e If M is present in equimolar or more relative to MAN, unreacted M
The main point is that although it is related to the rate of reduction of AN, it is not related to the minimum concentration of unreacted VAN (see Figure vI2). Furthermore, in order to maintain the amidation yield, it is necessary to pay attention not to change the reaction temperature and not to increase the molar ratio of sulfuric acid to MAN. This is interpreted to be due to an equilibrium phenomenon occurring between amide and methacrylic acid. That is, when MAN is reacted with sulfuric acid and water, methacrylamide sulfate is produced, but if water is in excess than theory J1 (the theory J1), methacrylic acid is produced by sequential reactions. Since the rate at which methacrylamide sulfate is generated from water is faster than the rate at which methacrylic acid is generated from methacrylamide sulfate and water, the reaction that generates methacrylamide sulfate proceeds primarily from MAN. It is thought that a state of equilibrium is reached between methacrylamide sulfate and methacrylamide sulfate, followed by an equilibrium state between methacrylamide sulfate and methacrylic acid, and at this point an equilibrium between the three is reached. If you think about it, it is easy to understand that in the exothermic reaction where methacrylamide is produced from MAN, the level of unreacted MAN crystallizes when the reaction temperature is high. Water plays an extremely important role in reduction by reaction, but if the amount of water exceeds the required amount, the rate of reduction of unreacted MAN decreases, and in the case of esterification, the by-product of methacrylic acid This is probably because methacrylic acid has a higher boiling point and is easier to polymerize than MMA.

ＭＭＡとメタクリル酸を合計した留出収率の低下が起こ
る〇 この為未反応ＭＡＮを低減せしめる工程の残存する水の
モル比は、供給ＭＡＮ　１モル当り０．０５〜０．３モ
ルの範囲が適する。上記範囲に水モル比を設定する方法
としては、アミド化工程と未反応ＭＡＮ低減工程に分割
する方法及びアミド化工程に全量供給する方法のいすで
も可能である。The total distillation yield of MMA and methacrylic acid decreases. Therefore, the molar ratio of remaining water in the step of reducing unreacted MAN should be in the range of 0.05 to 0.3 mol per 1 mol of MAN supplied. Suitable. The water molar ratio can be set within the above range by dividing the water into an amidation step and an unreacted MAN reduction step, or by supplying the entire amount to the amidation step.

また未反応ＭＡＮ低減工程の反応温度は、アミド化収率
の低下を抑制する為及び未反応ＭＡＮの水準を低くする
為の二つの理由から９０〜１２０℃という温度が好まし
い。またこの工程は工業的には反応工学上の理由から管
型反応器の使用が好才しい。この様にして未反応ＭＡＮ
を極めて低い水準に低減せしめた反応生成物を、通常の
方法でエステル化し精製することにより高品質なＭＭＡ
を収率、よく得る事ができる。Further, the reaction temperature in the unreacted MAN reduction step is preferably 90 to 120° C. for two reasons: to suppress a decrease in amidation yield and to lower the level of unreacted MAN. Further, from an industrial standpoint, it is preferable to use a tubular reactor in this process for reaction engineering reasons. In this way, unreacted MAN
High-quality MMA can be obtained by esterifying and purifying the reaction product, which has been reduced to an extremely low level, using conventional methods.
A good yield can be obtained.

本発明は第一に残存ニトリル低減の為に苛酷な反応条件
を選ばざるを得なかった従来法に対し、温和な条件を設
定する事が可能となり、収率低下や′副生成物の増加を
ほとんど起こさずに未反応ＭＡＮを低減する事が出来る
。第二に従来法に比し比較的低い硫酸モル比を選ぶ事が
可能となり、硫酸使用量の低減及び副生型硫安液量の低
減にも寄与する。第三に未反応ＭＡＮを低減する為の特
別な添加物質や処理剤を必要とせず極めて簡単であり且
つ経済的である。第四にエステル化後の精製工程で蒸留
により未反応ＭＡＮを分離する方法と、比較し、設備費
が低く、蒸気ｉ、（も少く極めて経炎的である。この様
に本発明は品質面及び経済面の両面に優れたプロセスを
提供するものである。Firstly, the present invention makes it possible to set mild conditions in contrast to the conventional method, which had to choose harsh reaction conditions to reduce residual nitrile, thereby reducing yields and increasing by-products. Unreacted MAN can be reduced with almost no occurrence. Second, it is possible to select a relatively low sulfuric acid molar ratio compared to conventional methods, which contributes to reducing the amount of sulfuric acid used and the amount of by-product ammonium sulfate solution. Thirdly, it is extremely simple and economical since it does not require special additives or processing agents to reduce unreacted MAN. Fourthly, compared to the method of separating unreacted MAN by distillation in the purification process after esterification, the equipment cost is low, the steam i. It provides a process that is superior in terms of both economic and economic aspects.

次に本発明を実施例により詳細に説明するが、本発明は
その要旨をこえない限り以下の実施例に限定されるもの
ではない６ 実施例　１ ＭＡＮ及び８４．５％硫酸水溶液をそれぞれ７．Ｑ１Ｒ
１／分、６　、ＯＲ１／分（ｕＡＮ／ａ、ｓｏ４／ｕ、
ｏ　＝１／ｉ、１／１．１　）の速度で第一槽反応器に
供給する。第一槽反応器は１Ｊ、フラスコに攪拌機及び
凝縮機を付してあり測管により連続的に渇合液を抜出せ
る構造を持つＯ油浴温度を調整して反応温度を１１０℃
に保ち４００分間反応せるｏｔＪＩＪ、槽反応器の抜出
液は１１度差にｌり第二槽反応器に連続的に供給される
０第二槽反応器は第一槽反応器と同じ構造であり、第一
槽反応器抜出液を１２０℃で４００分間反応せる。？ぎ
に第二槽反応器抜出液を高度差により内径１５ｓ＋ｍ長
さ１．０ｆｆｉの細管形反応器に導びき油浴により反応
器の内温を１２０℃に保ち１５分間反応させる。細管形
反応器の抜出液を分析した所、未反応ＭＡＮ　（１％度
は５１０　ＰＩ）ｍ　（供給ＭＡＮ　１モル基準のモル
比率。Next, the present invention will be explained in detail with reference to examples, but the present invention is not limited to the following examples unless the gist thereof is exceeded.Example 1 MAN and 84.5% sulfuric acid aqueous solution were prepared in 7. Q1R
1/min, 6, OR1/min (uAN/a, so4/u,
o = 1/i, 1/1.1) to the first tank reactor. The first tank reactor is a 1J flask equipped with a stirrer and a condenser, and has a structure that allows continuous extraction of the quenched liquid through a measuring tube.The temperature of the O oil bath is adjusted to bring the reaction temperature to 110℃.
The liquid extracted from the tank reactor is continuously supplied to the second tank reactor with a difference of 11 degrees.The second tank reactor has the same structure as the first tank reactor. The effluent from the first tank reactor is reacted at 120°C for 400 minutes. ? Next, the liquid discharged from the second tank reactor was introduced into a capillary reactor having an inner diameter of 15 s + m and a length of 1.0 ffi due to the height difference, and the reactor was reacted for 15 minutes while maintaining the internal temperature of the reactor at 120° C. using an oil bath. Analysis of the liquid extracted from the capillary reactor revealed that unreacted MAN (1% degree is 510 PI) m (molar ratio based on 1 mole of supplied MAN).

以後アミド中の未反応ニトリルの濃度は同じ表現をする
０）であり、残存水は供給ＭＩＪ　１モルａｉすｏ、ｏ
ｓモルであり、アミド化収率は９８．５％であった。続
いて前工程の細管型反応器の出し液を連続的に　ｆｆｉ
留時開時間１分間合槽に尋ひき０．１５ｄ／分の速度で
供給される水と混合した後内径１５ｆ１１長さ２．０ｍ
の細管型反応器に導びき１１０℃で５００分間反応せ１
反応滲出口液を分析した所、未反応ＭＡＮは５６　ｐｐ
ｍ　、残存水は供給ＭＡｌ’１モル当り０．０６モル、
アミド化収率は９８．２　％であった〇 つぎに５４１１の反応器をオーバーフロー形式で直列に
接続したエステル化装置でエステル化を行う０各反応器
には攪拌機及び蒸気留出配管が付してあり、第１〜第５
反応器の液容量は各々１０００１１４であり第４及び第
５槽の液容量は各々５００　Ｒ１である。前工程の細管
型反応器の出口液及び６１．４％メタノール水溶液を８
．５　ｄ１分の速度でエステル化第一槽に供給し、順次
第二槽から第五槽までを通過させてエステル化を行う。Hereafter, the concentration of unreacted nitrile in the amide is 0) using the same expression, and the remaining water is 1 mol aio,o of the supplied MIJ.
s mol, and the amidation yield was 98.5%. Next, the liquid discharged from the capillary reactor in the previous step was continuously fed to ffi.
After mixing with water supplied to the tank at a rate of 0.15 d/min for 1 minute during retention and opening time, the inner diameter is 15 f11 and the length is 2.0 m.
The mixture was introduced into a capillary reactor and reacted at 110°C for 500 minutes.
Analysis of the reaction effluent revealed that unreacted MAN was 56 pp.
m, residual water is 0.06 mol per mol of fed MAl',
The amidation yield was 98.2%.Next, esterification was carried out in an esterification device in which 5411 reactors were connected in series in an overflow format.Each reactor was equipped with a stirrer and steam distillation piping. There are 1st to 5th
The liquid capacity of each reactor is 1000114, and the liquid capacity of the fourth and fifth tanks is each 500 R1. The outlet liquid from the capillary reactor in the previous step and the 61.4% methanol aqueous solution were
．． It is supplied to the first esterification tank at a rate of 5 d1 min, and is passed sequentially through the second tank to the fifth tank to carry out esterification.

６槽の反応条件は第一槽が９０℃、第二槽が１１０℃、
第三槽が１２０℃、第四槽が１５０℃、第五槽が１４０
℃の温度であり、第四槽及び第五槽には各々熱水を１．
５１７分の割合で供給する。The reaction conditions for the 6 tanks are 90°C for the first tank, 110°C for the second tank,
The third tank is 120℃, the fourth tank is 150℃, and the fifth tank is 140℃.
℃, and the fourth and fifth tanks each contain 1.
It is supplied at a rate of 517 minutes.

６槽の蒸発成分を反応系外に取り出し凝縮させて得られ
た液中のＭＭＡ、メタクリル酸、未反応ＭＡＲを分析し
た結果、供給ＭＡＮ基準のＭＭＡ収率は９４．２　％で
あり、メタクリル酸収率は３．１チであった。又ＭＭＡ
及びメタクリル酸の合Ｉｔ重量−こ対する未反応ＭＡＮ
の重量比は２９　ｐｐｍであったＯ 実施例　２ 実施例１の第一工程と同条件で反応を実施して得られる
反応生成物を、ｏ、４５−７分の速度で供給される水と
混合した後、細管型反応器に導ひき１１０℃で１２０分
間反応させるＯ得られた反応生成物を分析した所、未反
応ＭＡＮは１６ｐｐｍ、残存水は供給ＭＡＮ　１モル当
り０．２２モｌし。As a result of analysis of MMA, methacrylic acid, and unreacted MAR in the liquid obtained by taking the evaporated components from the six tanks out of the reaction system and condensing them, the MMA yield based on the supplied MAN was 94.2%, and the MMA yield was 94.2%, and the MMA yield was 94.2% based on the supplied MAN. The yield was 3.1 cm. Also MMA
and methacrylic acid combined It weight vs. unreacted MAN
The weight ratio of O was 29 ppm. Example 2 The reaction product obtained by carrying out the reaction under the same conditions as in the first step of Example 1 was mixed with water supplied at a rate of 45-7 min. After mixing, the mixture was introduced into a capillary reactor and reacted at 110°C for 120 minutes. Analysis of the resulting reaction product revealed that unreacted MAN was 16 ppm, and residual water was 0.22 mol per 1 mol of MAN supplied. .

アミド化収率は９７．５％であった。続いて実施例１と
同条件でエステル化を笑施し、得られた留出液を分析し
た所、供給ＭＡＮ基準のＭＭＡ収率は９１．１％であり
、メタクリル酸収率は５．２％であった。またＭＭＡ及
びメタクリル酸の合計重量に対する未反応ＭＡＮの重量
比は１４　ｐｐｍであったＯ実施例　５ 実施例１の第一工程と同条件で反応を実施して得られた
反応生成物を、水を添加せずにそのまま細管型反応器に
導びき１１０℃で５００分間反応せる。得られた反応生
成物を分析した所。Amidation yield was 97.5%. Subsequently, esterification was carried out under the same conditions as in Example 1, and the resulting distillate was analyzed, and the yield of MMA based on the supplied MAN was 91.1%, and the yield of methacrylic acid was 5.2%. Met. In addition, the weight ratio of unreacted MAN to the total weight of MMA and methacrylic acid was 14 ppm. The mixture was directly introduced into a capillary reactor without the addition of any of the following, and reacted at 110°C for 500 minutes. Analysis of the resulting reaction product.

未反応ＭＡＮは７５Ｐｌ）ｍ、残存水は供給ＭＡＮ　１
　％ル当り０．０３モル、アミド化収率は９８．０　％
であった０続いて実施例１と同条件でエステル化を実施
し、得られた留出液を分析した所、供給ＭＡＮ基準のＭ
ＭＡ収率は９４．５　％であり、メタクリル酸収率は２
．６チであったＯまたＭＭＡ及びメタクリル酸の合計重
量に対する未反応ＭＡＮの重量比は６２１’１ｐ１ｎで
あった□ 実施例　４ ＭＡＮ及び８５．５　％硫酸水溶液をそれぞれ７．０吟
傍。Unreacted MAN is 75Pl)m, residual water is supplied to MAN 1
0.03 mol per % mol, amidation yield is 98.0%
0 Subsequently, esterification was carried out under the same conditions as in Example 1, and the obtained distillate was analyzed.
The MA yield was 94.5% and the methacrylic acid yield was 2.
．． Also, the weight ratio of unreacted MAN to the total weight of MMA and methacrylic acid was 621'lp1n.' Example 4 MAN and 85.5% sulfuric acid aqueous solution were each mixed with 7.0 min.

６．１　ｍｕ／分（ＭＡＮ／Ｈ！８０．／Ｈ，Ｏ−１／
１，１／　１．２　）の速度で第一槽反応器に供給し、
１１０℃で４０分反応させる。続いて第二槽反応器で１
２０℃で４０分間、＃ｌｌ酸型反応器１２０℃で１５分
間反応させる０この細管型反応器の出口液を分析した所
、未反応ＭＡＮは４０５ＰＰＩｎ、残存水は供給ＭＡＮ
　１モル当り０．０９モル、アミド化収率は９８．４　
％であった。続いて前工程の反応器出口液を水を添加せ
ずにそのまま細管型反応器に導びき１１０℃で３００分
間反応せ、得られた反応生成物を分析した所、未反応Ｍ
ＡＮは５８ｐｐｍ。6.1 mu/min (MAN/H!80./H, O-1/
1,1/1.2) to the first tank reactor,
React at 110°C for 40 minutes. Then, in the second tank reactor, 1
React at 20°C for 40 minutes, #ll acid type reactor at 120°C for 15 minutes 0 Analysis of the outlet liquid from this capillary reactor revealed that unreacted MAN was 405 PPIn, and residual water was 405 PPIn.
0.09 mol per mol, amidation yield 98.4
%Met. Next, the reactor outlet liquid from the previous step was directly introduced into a capillary reactor without adding water and reacted at 110°C for 300 minutes, and the resulting reaction product was analyzed and found to be unreacted M.
AN is 58ppm.

残存水は供給ＭＡ１１１モル当り０．０５モル、アミド
化収率は９８．１　％であった。続いて実施例１と同条
件でエステル化を実施し、得られた留出液を分析した所
、供給ＭＡｌｉ基準のＭＭＡ収率は９５．９％であり、
メタクリル酸収率は５．５　ＴｏであったＯまたＭＭＡ
及びメタクリル酸の合計重量に対する未反応ＭＡＮの重
量比は３５　ｐｐｍであった０比較例　１ ＭＡＮ及び８５．０　％硫酸水溶液をそれぞれ７．Ｏｍ
／ｆｉ。The residual water was 0.05 mol per 111 mol of MA fed, and the amidation yield was 98.1%. Subsequently, esterification was carried out under the same conditions as in Example 1, and the resulting distillate was analyzed, and the MMA yield based on the supplied MAli was 95.9%.
The methacrylic acid yield was 5.5 ToO or MMA.
The weight ratio of unreacted MAN to the total weight of methacrylic acid and methacrylic acid was 35 ppm. 0 Comparative Example 1 MAN and 85.0% sulfuric acid aqueous solution were each added to 7.5 ppm. Om
/fi.

５．９５ｄ／分（ＭＡＮ／Ｈ！Ｓｏ、／Ｈ，Ｏ＝　１　
／　１．１　／　１．０６　）の速度で第一槽反応器に
供給し１１０℃で４００分間反応せる。引続き第二槽反
応器に於いて１２０℃で４０分間、細管型反応器に於い
て１２０℃で１５分間反応させる。細管型反応器の出口
では未反応ＭＡＮは１２００１）Ｉ）ｍであり、アミド
化収率は９７．８％であった０また残存水分は供給ＭＡ
Ｎ　１モル当り０．０１モルであった。続いて細管型反
応器に導びき１１０℃で５００分間反応せたが、未反応
ＭＡＮは７９０１）１）ｍと高濃度であり、アミド化収
率は９７．２％であった。さらに細管型反応器を継ぎ足
す重化より、１１０℃で６０分間及び９０分間反応出来
る様にしたが。5.95d/min (MAN/H!So, /H,O= 1
/ 1.1 / 1.06) to the first tank reactor and reacted at 110°C for 400 minutes. Subsequently, the reaction was carried out at 120° C. for 40 minutes in a second tank reactor and for 15 minutes at 120° C. in a capillary reactor. At the outlet of the capillary reactor, the unreacted MAN was 12001)I)m, and the amidation yield was 97.8%.
It was 0.01 mol per 1 mol of N. Subsequently, it was introduced into a capillary reactor and reacted at 110°C for 500 minutes, but the unreacted MAN was at a high concentration of 7901)1)m, and the amidation yield was 97.2%. Furthermore, by adding a capillary reactor, it was possible to react at 110°C for 60 minutes and 90 minutes.

６００分間反応せた場合番こは未反応ＭＡＮは８０５ｐ
ｐｍ、アミド化収率は９６．５％であり、９００分間反
応せた場合には未反応ＭＡＮはａ　ｓ　ｏ　ｐｐｍ、ア
ミド化収率は９５．８ｅｓと３００分間反応させた場合
に較べ未反応ＭＡＮは逆に若干増加し、アミド化収率は
低下した。When reacting for 600 minutes, the unreacted MAN is 805p
pm, amidation yield was 96.5%, unreacted MAN was as o ppm when reacted for 900 minutes, and amidation yield was 95.8es compared to when reacted for 300 minutes. On the contrary, MAN increased slightly and amidation yield decreased.

比較例　２ 比較例１の第一工程の出口液を細管型反応器に導びき、
１３０’Ｃで５０分間反応させたが、未反応ＭＡＮは１
１６０１）Ｉ）ｍと、はとんど低減せずアミド化収率は
９６．３％と低下した０又１５．０’Ｃで６０分間反応
させた場合も未反応ＭＡＮは１２４０　ｐＩ）ｍと低減
せず、アミド化収率は９４．９％と大幅に低下した。Comparative Example 2 The outlet liquid of the first step of Comparative Example 1 was led to a capillary reactor,
The reaction was carried out at 130'C for 50 minutes, but the unreacted MAN was 1
When reacting with 1601)I)m at 0 or 15.0'C for 60 minutes, the amidation yield decreased to 96.3% without any reduction, the unreacted MAN was 1240 pI)m. The amidation yield was significantly reduced to 94.9%.

比較例　３ 実施例１の第一工程と同条件で反応を実施して得られる
反応生成物を、Ｑ、９ｄ１分の速度で供給される水と混
合した後、細管型反応器に導びき１１０℃で１８０分間
反応させる０得られた反応生成物を分析した所、未反応
ＭＡＮは５’　ｐｐｍ。Comparative Example 3 A reaction product obtained by carrying out the reaction under the same conditions as in the first step of Example 1 was mixed with water supplied at a rate of Q, 9d1 min, and then introduced into a capillary reactor at 110 When the reaction product obtained was analyzed at ℃ for 180 minutes, the unreacted MAN was 5' ppm.

残存水は供給ＭＡＮ　１モル当り０．３５モル、アミド
化収率９７．２％であった。続いて実施例１と同条件で
エステル化を行い、得られた留出液を分析した所、供給
ＭＡＮ基準のＭＭＡ収率は８６．８　％であり、メタク
リル酸収率は７．５チであった。The residual water was 0.35 mol per 1 mol of MAN supplied, and the amidation yield was 97.2%. Subsequently, esterification was carried out under the same conditions as in Example 1, and the resulting distillate was analyzed, and the yield of MMA based on the supplied MAN was 86.8%, and the yield of methacrylic acid was 7.5%. there were.

【図面の簡単な説明】[Brief explanation of the drawing]

第１図は残存水分量と未反応ＭＡＮとの相関グラフ、第
２図は反応時間と未反応ＭＡＮとの相関グラフである。 第　１１４ 残存Ｈ２０Δ士込ＭＡＮ　（モル比） 第２図 反応時間（Ｈｒ） 手続ｈｌｉ正書 昭和５７年１１’Ｊ１８ｕ １゛冒′１庁長官　　　　　　殿 １　中（′１の表示　　　　　　　　　、゛、析ψ昭和
５７　イ１　％　　　　願第１７５６４９υ２゛発明０
名称　メタクリル酸メチルの製造法３、ｈｌｉｊｌをす
る者 １Ｊｌｌｆｉとの関係　特許出願人 ４、代理人 氏　名　　（７００９）　　弁理士　久　　門　　　　
知＆　　ｒ＋ｌｉ　ｉｌＸノ内ｉ−＋　　別紙ｆ）　＞
Ｉｌｌ　リ（１）明細書第１４頁第１１行目〜第１２行
目の「続いて細管型反応器に導き・・・」を「続いて前
工程の反応生成物を細管型反応器に導き・・・・」と補
正する。 （２）図面「第１図、第２図」を取り下げ、別添「第１
図、第２図」と差替える。 第１図 残存１−１．０／仕込ＭＡＮ（モル比）第２図 反応時間（Ｉｌｒ）FIG. 1 is a correlation graph between residual water content and unreacted MAN, and FIG. 2 is a correlation graph between reaction time and unreacted MAN. No. 114 Residual H20Δ MAN (mole ratio) Fig. 2 Reaction time (Hr) Procedure hli Original book 1981 11'J18u 1゛Effect'1 Agency Director General 1 Middle (Indication of '1 ,゛, Analysis ψShowa 57 I1 % Application No. 175649υ2゛Invention 0
Name: Process for producing methyl methacrylate 3, person who conducts hlijl 1: Relationship with Jllfi Patent applicant: 4, agent name (7009) Patent attorney Hisamon
knowledge & r+li ilX no uchi i-+ Attachment f) >
Ill Re(1) Specification, page 14, lines 11 to 12, "Then, the reaction product of the previous step is introduced into the capillary reactor..." is replaced with "The reaction product of the previous step is then introduced into the capillary reactor.""..." I corrected myself. (2) Withdraw drawings “Figures 1 and 2” and attached “Figure 1”
Figure 2. Figure 1: Remaining 1-1.0/Charging MAN (molar ratio) Figure 2: Reaction time (Ilr)

Claims (2)

【特許請求の範囲】[Claims] （１）　　メククリロニトリルを硫酸及び水と反応させ
メタクリル酸アミドとし、次いでエステル化しメタクリ
ル酸メチルを製造する方法において、メタクリロニトリ
ルを硫酸の存在下に最大の゛γアミド化収率得られるま
でアミド化を進行せしめる工程、前記工程の反応生成物
を仕込メタクリロニトリル１モル当り０．０５〜０．３
モルの水の存在下、前記アミド化収率を実質的に維持し
たまま未反応メタクリロニトリルを低減せしめる工程及
びエステル化工程とからなる事を特徴とするメタクリル
酸メチルの製造法。(1) In the method of producing methyl methacrylate by reacting meccrylonitrile with sulfuric acid and water to form methacrylic acid amide and then esterifying it, methacrylonitrile is reacted in the presence of sulfuric acid until the maximum yield of γ-amidation is obtained. Step of advancing amidation, charging the reaction product of the above step, 0.05 to 0.3 per mole of methacrylonitrile
A method for producing methyl methacrylate, comprising the steps of reducing unreacted methacrylonitrile while substantially maintaining the above-mentioned amidation yield in the presence of mol of water, and an esterification step. （２）アミド化収率が９６〜９９チである特許請求の範
囲（１）項に記載のメタクリル酸メチルの製造法。(2) The method for producing methyl methacrylate according to claim (1), wherein the amidation yield is 96 to 99%.