JP6036402B2 - Method for producing (meth) acrylic acid ester - Google Patents

Method for producing (meth) acrylic acid ester Download PDF

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JP6036402B2
JP6036402B2 JP2013035874A JP2013035874A JP6036402B2 JP 6036402 B2 JP6036402 B2 JP 6036402B2 JP 2013035874 A JP2013035874 A JP 2013035874A JP 2013035874 A JP2013035874 A JP 2013035874A JP 6036402 B2 JP6036402 B2 JP 6036402B2
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大作 兼子
大作 兼子
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Mitsubishi Chemical Corp
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本発明は(メタ)アクリル酸エステルの製造方法に係り、特に、(メタ)アクリル酸とアルコールとを酸触媒の存在下に反応させて得られた(メタ)アクリル酸エステルを含むエステル化反応液から(メタ)アクリル酸エステルと重質分とを蒸留分離し、この重質分を重質分解器に送給して分解、エステル化反応させて有価物を回収するに当たり、重質分解器のリボイラーにおける閉塞運転トラブルを防止して、長期に亘り安定かつ効率的に(メタ)アクリル酸エステルを製造する方法に関する。   The present invention relates to a method for producing (meth) acrylic acid ester, and in particular, an esterification reaction liquid containing (meth) acrylic acid ester obtained by reacting (meth) acrylic acid and alcohol in the presence of an acid catalyst. The (meth) acrylic acid ester and heavy component are separated from the product by distillation, and the heavy component is fed to the heavy cracker for decomposition and esterification to recover valuable materials. The present invention relates to a method for preventing a clogging operation trouble in a reboiler and producing a (meth) acrylic acid ester stably and efficiently over a long period of time.

なお、本明細書において、(メタ)アクリル酸はアクリル酸とメタクリル酸との総称であり、そのいずれか一方でもよく双方でもよい。   In the present specification, (meth) acrylic acid is a general term for acrylic acid and methacrylic acid, and either one or both of them may be used.

(メタ)アクリル酸エステルは重合性を有する化合物であって、得られる重合体に優れた特性を付与することができることから、種々の用途、例えば塗料、接着剤、粘着剤、合成樹脂、繊維などの原料として幅広く用いられている。   (Meth) acrylic acid ester is a compound having polymerizability, and can give excellent properties to the resulting polymer, so that it can be used in various applications such as paints, adhesives, pressure-sensitive adhesives, synthetic resins, fibers, etc. It is widely used as a raw material.

(メタ)アクリル酸エステルの製造方法としては、酸触媒の存在下、(メタ)アクリル酸とアルコールとをエステル化反応させる方法が一般に広く用いられている。更に、得られたエステル化反応液から酸触媒及び未反応の(メタ)アクリル酸を除去するために、水で抽出後、アルカリ水溶液で処理し、その後、(メタ)アクリル酸エステルを含有する油層(有機層)と、このような洗浄、中和処理で生じる水及び中和塩を含有する水層とを静置槽で静置分離することが一般的に行われている(例えば特許文献1)。   As a method for producing (meth) acrylic acid ester, a method in which (meth) acrylic acid and an alcohol are esterified in the presence of an acid catalyst is generally widely used. Further, in order to remove the acid catalyst and unreacted (meth) acrylic acid from the obtained esterification reaction solution, the oil layer is extracted with water and then treated with an alkaline aqueous solution, and then contains (meth) acrylic acid ester. In general, the organic layer is separated from the aqueous layer containing water and neutralized salt generated by such washing and neutralization treatment in a stationary tank (for example, Patent Document 1). ).

図1は、従来の一般的なアクリル酸エステルの製造プロセスを示す系統図であって、アクリル酸、アルコールは、酸触媒の存在下、エステル化反応器1を経てエステル化反応し、エステル化反応で生成する水は、エステル化反応器1から系外へ排出される。エステル化反応液は、抽出塔(触媒回収塔)2で水と向流接触して酸触媒が抽出分離、回収され、回収された触媒の一部はエステル化反応器1の入口側へ循環されて再利用され、残部は後段の重質分解器7に送給され、重質分解器7における重質分の分解に使用される。抽出塔2からの反応液は、アクリル酸分離塔3でアルカリ水溶液が添加されて中和されると共に、水で洗浄される。アクリル酸分離塔3からの中和・洗浄処理液は、静置槽4で油水分離され、水相は系外へ排出され、油相は次の軽沸分離塔5に送給されて未反応のアルコール等の軽沸分が蒸留分離され、塔頂より抜き出される。軽沸分離塔5の塔底液は、次の精製塔6に送給されて重質分が蒸留分離され、製品の高純度アクリル酸エステルが塔頂より取り出される。精製塔6の塔底液は、重質分解器7に送給され、重質分の分解、蒸留でアクリル酸やアクリル酸エステルやアルコールを生成させ、これら有価物は反応器に循環させ、この重質分解器7の塔底液は廃油として系外へ排出される。なお、図中、7Aは重質分解器7のリボイラーである。   FIG. 1 is a system diagram showing a conventional process for producing a typical acrylate ester. Acrylic acid and alcohol undergo an esterification reaction through an esterification reactor 1 in the presence of an acid catalyst, and an esterification reaction is performed. The water produced in is discharged from the esterification reactor 1 to the outside of the system. The esterification reaction solution is countercurrently contacted with water in the extraction tower (catalyst recovery tower) 2 to extract and recover the acid catalyst, and a part of the recovered catalyst is circulated to the inlet side of the esterification reactor 1. The remaining portion is sent to the heavy decomposer 7 at the subsequent stage, and is used for heavy component decomposition in the heavy decomposer 7. The reaction solution from the extraction tower 2 is neutralized by adding an alkaline aqueous solution in the acrylic acid separation tower 3 and washed with water. The neutralized and washed treatment liquid from the acrylic acid separation tower 3 is separated into oil and water in the stationary tank 4, the aqueous phase is discharged out of the system, and the oil phase is fed to the next light boiling separation tower 5 and unreacted. The light boiling components such as alcohol are distilled and separated from the top of the column. The bottom liquid of the light boiling separation tower 5 is fed to the next purification tower 6 where the heavy components are separated by distillation, and the high-purity acrylic ester of the product is taken out from the top of the tower. The bottom liquid of the purification tower 6 is sent to the heavy cracker 7, where acrylic acid, acrylic acid ester and alcohol are produced by decomposition and distillation of heavy components, and these valuable materials are circulated in the reactor. The bottom liquid of the heavy cracker 7 is discharged out of the system as waste oil. In the figure, 7A is a reboiler of the heavy cracker 7.

即ち、精製塔6の塔底液には、アクリル酸とアルコールとのエステル化反応工程で副生したマレイン酸アルキル、ダイマー酸アルキル、アルコキシプロピオン酸アルキル、ヒドロキシプロピオン酸アルキル等のミカエル付加物が含まれているため、この塔底液を重質分解器7に送給し、抽出塔2からの回収触媒と原料タンクからのアクリル酸を添加してこれらを分解し、また、エステル化反応させると共に蒸留分離して、アルコール、アクリル酸アルキル、アクリル酸等の有価物を回収し、これらを反応系に循環させる。なお、この重質分解器7には、製造プロセスのプロセス外抜き出し液(反応開始時の規格外プロセス液、反応停止時のプロセス抜き出し液、アクリル酸分離塔、静置槽の油水界面より抜き出される有機層及び/又は水層のうち有機層のみを分離したもの等)も導入されて処理される場合もある。   That is, the bottom liquid of the purification tower 6 contains Michael adducts such as alkyl maleate, alkyl dimer acid, alkyl alkoxypropionate, alkyl hydroxypropionate and the like by-produced in the esterification reaction step of acrylic acid and alcohol. Therefore, the bottom liquid is fed to the heavy cracker 7 and the recovered catalyst from the extraction tower 2 and acrylic acid from the raw material tank are added to decompose them, and the esterification reaction is performed. By distilling and separating, valuable materials such as alcohol, alkyl acrylate, and acrylic acid are recovered, and these are circulated in the reaction system. The heavy cracker 7 is extracted from an out-of-process extraction liquid (a non-standard process liquid at the start of the reaction, a process extraction liquid at the time of the reaction stop, an acrylic acid separation tower, and an oil / water interface of a stationary tank). In some cases, an organic layer and / or an aqueous layer in which only the organic layer is separated or the like is also introduced and processed.

図2は、従来の一般的なアクリル酸エステルの製造プロセスを示す別の系統図であって、アクリル酸、アルコールは、固体酸触媒の存在下、エステル化反応器1を経てエステル化反応し、エステル化反応で生成する水は、エステル化反応器1から系外へ排出される。エステル化反応液は、アクリル酸分離塔3でアルカリ水溶液が添加されて中和されると共に、水で洗浄される。アクリル酸分離塔3からの中和・洗浄処理液は、静置槽4で油水分離され、水相は系外へ排出され、油相は次の溶媒回収塔(溶媒分離塔)8に送給されて溶媒が蒸留分離され、その後軽沸分離塔5に送給されて未反応のアルコール等の軽沸分が蒸留分離され、塔頂より抜き出される。軽沸分離塔5の塔底液は、次の精製塔6に送給されて重質分が蒸留分離され、製品の高純度アクリル酸エステルが塔頂より取り出される。精製塔6の塔底液は、重質分解器7に送給され、重質分の分解、蒸留でアクリル酸やアクリル酸エステルやアルコールを生成させ、これら有価物は反応器に循環させ、この重質分解器7の塔底液は廃油として系外へ排出される。なお、図中、7Aは重質分解器7のリボイラーである。   FIG. 2 is another system diagram showing a conventional general process for producing an acrylate ester, in which acrylic acid and alcohol undergo an esterification reaction through an esterification reactor 1 in the presence of a solid acid catalyst, Water produced by the esterification reaction is discharged out of the system from the esterification reactor 1. The esterification reaction liquid is neutralized by adding an alkaline aqueous solution in the acrylic acid separation tower 3 and washed with water. The neutralized and washed treatment liquid from the acrylic acid separation tower 3 is separated into oil and water in the stationary tank 4, the aqueous phase is discharged out of the system, and the oil phase is fed to the next solvent recovery tower (solvent separation tower) 8. Then, the solvent is separated by distillation, and then fed to the light boiling separation column 5 where light boiling components such as unreacted alcohol are distilled and separated from the top of the column. The bottom liquid of the light boiling separation tower 5 is fed to the next purification tower 6 where the heavy components are separated by distillation, and the high-purity acrylic ester of the product is taken out from the top of the tower. The bottom liquid of the purification tower 6 is sent to the heavy cracker 7, where acrylic acid, acrylic acid ester and alcohol are produced by decomposition and distillation of heavy components, and these valuable materials are circulated in the reactor. The bottom liquid of the heavy cracker 7 is discharged out of the system as waste oil. In the figure, 7A is a reboiler of the heavy cracker 7.

即ち、前述の如く、精製塔6の塔底液には、アクリル酸とアルコールとのエステル化反応工程で副生したマレイン酸アルキル、ダイマー酸アルキル、アルコキシプロピオン酸アルキル、ヒドロキシプロピオン酸アルキル等のミカエル付加物が含まれているため、この塔底液を重質分解器7に送給し、系外からの酸触媒と原料タンクからのアクリル酸を添加してこれらを分解し、また、エステル化反応させると共に蒸留分離して、アルコール、アクリル酸アルキル、アクリル酸等の有価物を回収し、これらを反応系に循環させる。なお、この重質分解器7には、前述の如く、製造プロセスのプロセス外抜き出し液(反応開始時の規格外プロセス液、反応停止時のプロセス抜き出し液、アクリル酸分離塔、静置槽の油水界面より抜き出される有機層及び/又は水層のうち有機層のみを分離したもの等)も導入されて処理される場合もある。   That is, as described above, the bottom liquid of the purification tower 6 includes Michael such as alkyl maleate, alkyl dimer acid, alkyl alkoxypropionate, alkyl hydroxypropionate, etc., which are by-produced in the esterification reaction step of acrylic acid and alcohol. Since adducts are contained, this bottom solution is sent to the heavy cracker 7, where acid catalyst from outside the system and acrylic acid from the raw material tank are added to decompose them, and esterification The reaction is conducted and separated by distillation to recover valuable materials such as alcohol, alkyl acrylate, and acrylic acid, and these are circulated in the reaction system. In addition, as described above, the heavy decomposer 7 includes an out-of-process extraction liquid (non-standard process liquid at the start of reaction, process extraction liquid at the time of reaction stop, acrylic acid separation tower, oil / water in a stationary tank, and the like. In some cases, an organic layer and / or an aqueous layer extracted from the interface are separated from the organic layer, and the like.

特許文献2には、(メタ)アクリル酸エステル精製工程で分離された重質分に酸触媒を添加して分解することにより、(メタ)アクリル酸、(メタ)アクリル酸エステル、及びアルコールを回収するに当たり、エーテル類の副生を抑制して高い回収率で分解する方法として、重質分に対する酸触媒の添加量を0.1〜1.0重量%(重質分と酸触媒との合計に対する酸触媒の濃度としては1.0重量%より少ない値となる。)とする方法が記載されているが、従来において、重質分解器の運転トラブルと酸触媒との関係についての検討はなされておらず、重質分解器の安定運転のために酸触媒濃度を調製することは行われていない。   In Patent Document 2, (meth) acrylic acid, (meth) acrylic acid ester, and alcohol are recovered by adding an acid catalyst to the heavy component separated in the (meth) acrylic acid ester purification step and decomposing it. In order to suppress the by-product of ethers and decompose at a high recovery rate, the amount of the acid catalyst added to the heavy component is 0.1 to 1.0% by weight (the total of the heavy component and the acid catalyst). The concentration of the acid catalyst is less than 1.0% by weight). However, conventionally, the relation between the operation trouble of the heavy cracker and the acid catalyst has been studied. The acid catalyst concentration is not adjusted for stable operation of the heavy cracker.

特開2003−231665号公報JP 2003-231665 A 特開2003−226668号公報JP 2003-226668 A

従来、精製塔6からの重質分を分解して有価物を回収する重質分解器7では、リボイラー7Aの閉塞トラブルで安定運転が阻害される問題があった。
重質分解器7のリボイラー7Aが閉塞した場合には、運転を停止してリボイラー7A内を洗浄する必要があり、長期連続運転を行えずに生産性が著しく低下したり、洗浄のためのコストが増えることとなる。
Conventionally, in the heavy decomposer 7 that decomposes heavy components from the purification tower 6 and collects valuables, there has been a problem that stable operation is hindered due to a clogging trouble of the reboiler 7A.
When the reboiler 7A of the heavy cracker 7 is blocked, it is necessary to stop the operation and clean the inside of the reboiler 7A. This makes it impossible to perform continuous operation for a long period of time, resulting in a significant decrease in productivity and the cost for cleaning. Will increase.

本発明は上記従来の問題点を解決し、このような(メタ)アクリル酸エステルの製造プロセスにおいて、重質分解器のリボイラーにおける閉塞トラブルを防止して、重質分解器を長期に亘り安定に連続運転可能とする(メタ)アクリル酸エステルの製造方法を提供することを課題とする。   The present invention solves the above-mentioned conventional problems, and in such a (meth) acrylic ester production process, prevents the clogging trouble in the reboiler of the heavy decomposer and makes the heavy decomposer stable for a long time. It aims at providing the manufacturing method of the (meth) acrylic acid ester which enables continuous operation.

本発明者らは、上記課題を解決すべく鋭意検討を重ねた結果、重質分解器のリボイラーの閉塞物の形成には、重質分解器に導入される酸触媒が関係しており、重質分解器に導入される酸触媒の濃度を制御することにより、この閉塞トラブルを抑制することができることを見出した。   As a result of intensive studies to solve the above-mentioned problems, the inventors of the present invention are concerned with the formation of the blocker of the reboiler of the heavy cracker, because an acid catalyst introduced into the heavy cracker is involved. It has been found that this clogging trouble can be suppressed by controlling the concentration of the acid catalyst introduced into the degrading device.

本発明はこのような知見に基づいて達成されたものであり、以下を要旨とする。   The present invention has been achieved based on such findings, and the gist thereof is as follows.

[1] (メタ)アクリル酸とアルコールとを酸触媒の存在下に反応させて(メタ)アクリル酸エステルを含むエステル化反応液を得る反応工程と、該エステル化反応液から(メタ)アクリル酸エステルと重質分とを蒸留分離する精製工程と、該重質分を酸触媒含有液との混合液として重質分解器に導入して分解、エステル化反応させることにより(メタ)アクリル酸エステル及びアルコールを含む有価物を回収する回収工程とを含む(メタ)アクリル酸エステルの製造方法において、下記(1)及び/又は(2)の条件を満たすことを特徴とする(メタ)アクリル酸エステルの製造方法。
(1) 前記酸触媒含有液の酸触媒濃度が5〜28重量
(2) 前記混合液の酸触媒濃度が1〜3重量%
[1] A reaction step in which (meth) acrylic acid and alcohol are reacted in the presence of an acid catalyst to obtain an esterification reaction liquid containing a (meth) acrylic acid ester, and (meth) acrylic acid from the esterification reaction liquid A (meth) acrylic acid ester is obtained by distilling and separating an ester and a heavy component, and then introducing the heavy component into a heavy cracker as a mixed solution with an acid catalyst-containing solution for decomposition and esterification. And a (meth) acrylic acid ester production method comprising a recovery step for recovering valuable materials including alcohol, wherein the (meth) acrylic acid ester satisfies the following conditions (1) and / or (2): Manufacturing method.
(1) The acid catalyst concentration of the acid catalyst-containing liquid is 5 to 28 % by weight .
(2) The acid catalyst concentration of the mixed solution is 1 to 3% by weight.

[2] 前記酸触媒含有液の酸触媒濃度が10〜25重量%で、前記混合液の酸触媒濃度が1〜2.5重量%であることを特徴とする[1]に記載の(メタ)アクリル酸エステルの製造方法。 [2] The (meta) according to [1], wherein the acid catalyst concentration of the acid catalyst-containing liquid is 10 to 25% by weight, and the acid catalyst concentration of the mixed liquid is 1 to 2.5% by weight. ) A method for producing acrylic ester.

[3] 前記エステル化反応液中の酸触媒を水で抽出して回収する抽出工程を含み、前記混合液は、該抽出工程からの酸触媒含有液と原料(メタ)アクリル酸を含むことを特徴とする[1]又は[2]に記載の(メタ)アクリル酸エステルの製造方法。 [3] It includes an extraction step of extracting and recovering the acid catalyst in the esterification reaction solution with water, and the mixed solution contains an acid catalyst-containing solution from the extraction step and a raw material (meth) acrylic acid. The method for producing a (meth) acrylic acid ester according to [1] or [2], which is characterized.

[4] 前記有価物を前記反応工程に返送する返送工程を含むことを特徴とする[1]ないし[3]のいずれかに記載の(メタ)アクリル酸エステルの製造方法。 [4] The method for producing a (meth) acrylic acid ester according to any one of [1] to [3], including a return step of returning the valuable material to the reaction step.

[5] 前記重質分解器の塔頂より前記有価物を回収し、前記重質分解器の塔底液を廃油として系外に排出する(メタ)アクリル酸エステルの製造方法であって、該重質分解器に導入される前記混合液に対する該廃油の割合が10〜40重量%であることを特徴とする[1]ないし[4]のいずれかに記載の(メタ)アクリル酸エステルの製造方法。 [5] A method for producing a (meth) acrylic acid ester, wherein the valuable material is recovered from the top of the heavy cracker, and the bottom liquid of the heavy cracker is discharged out of the system as waste oil, The production of (meth) acrylic acid ester according to any one of [1] to [4], wherein the ratio of the waste oil to the mixed liquid introduced into the heavy cracker is 10 to 40% by weight Method.

本発明によれば、(メタ)アクリル酸エステル製造プロセスにおいて、(メタ)アクリル酸エステルと蒸留分離された重質分から有価物を回収するための重質分解器のリボイラーの閉塞トラブルを防止して、長期に亘り、安定かつ効率的な(メタ)アクリル酸エステルの製造を行える。   According to the present invention, in the (meth) acrylic acid ester manufacturing process, the trouble of clogging the reboiler of the heavy cracker for recovering valuable materials from the heavy fraction distilled and separated from the (meth) acrylic acid ester is prevented. Thus, stable and efficient production of (meth) acrylic acid esters can be performed over a long period of time.

一般的なアクリル酸エステルの製造プロセスの一例を示す系統図である。It is a systematic diagram which shows an example of the manufacturing process of a general acrylic ester. 一般的なアクリル酸エステルの製造プロセスの別の例を示す系統図である。It is a systematic diagram which shows another example of the manufacturing process of a general acrylate ester.

以下に本発明の(メタ)アクリル酸エステルの製造方法の実施の形態を詳細に説明する。   Hereinafter, embodiments of the method for producing a (meth) acrylic acid ester of the present invention will be described in detail.

本発明の(メタ)アクリル酸エステルの製造方法は、(メタ)アクリル酸とアルコールとを酸触媒の存在下に反応させて(メタ)アクリル酸エステルを含むエステル化反応液を得る反応工程と、このエステル化反応液から(メタ)アクリル酸エステルと重質分とを蒸留分離する精製工程と、分離された重質分を酸触媒含有液との混合液として重質分解器に導入して分解、エステル化反応させることにより(メタ)アクリル酸エステル及びアルコールを含む有価物を回収する回収工程とを含む(メタ)アクリル酸エステルの製造方法において、下記(1)及び/又は(2)の条件を満たすことを特徴とする。
(1) 前記酸触媒含有液の酸触媒濃度が28重量%以下
(2) 前記混合液の酸触媒濃度が1〜3重量%
The method for producing a (meth) acrylic acid ester of the present invention includes a reaction step of reacting (meth) acrylic acid and an alcohol in the presence of an acid catalyst to obtain an esterification reaction liquid containing a (meth) acrylic acid ester, A purification process in which (meth) acrylic acid ester and heavy components are separated from this esterification reaction solution by distillation, and the separated heavy components are introduced into a heavy decomposer as a mixture with an acid catalyst-containing solution for decomposition. In the method for producing a (meth) acrylic acid ester, which comprises a recovery step of recovering a valuable product containing a (meth) acrylic acid ester and an alcohol by an esterification reaction, the following conditions (1) and / or (2) It is characterized by satisfying.
(1) The acid catalyst concentration of the acid catalyst-containing liquid is 28% by weight or less (2) The acid catalyst concentration of the mixed liquid is 1 to 3% by weight

即ち、本発明者は、重質分解器のリボイラーの閉塞トラブルの原因について検討した結果、リボイラー内の閉塞物の形成には酸触媒が寄与しており、重質分解器への酸触媒の導入量を上記(1)及び/又は(2)、好ましくは上記(1)及び(2)の条件を満たすように制御することにより、リボイラー内の閉塞物の形成を抑制して、重質分解器の運転トラブルを防止することができることを知見した。   That is, as a result of examining the cause of the clogging trouble of the reboiler of the heavy decomposer, the present inventor has found that the acid catalyst contributes to the formation of the clogged material in the reboiler, and the introduction of the acid catalyst into the heavy decomposer. By controlling the amount so as to satisfy the above conditions (1) and / or (2), preferably satisfying the above conditions (1) and (2), the formation of a plug in the reboiler is suppressed, and the heavy cracker It was found that it was possible to prevent driving troubles.

本発明において、酸触媒含有液とは、重質分解器に導入される液のうち、酸触媒を含む液を指し、図1における抽出塔2の塔底から抜き出される液の流通液、即ち、図1の「※1」で示す配管の流通液が該当する。或いは、図2における「※1」で示す配管の流通液が該当する。また、重質分と酸触媒含有液との混合液とは、この酸触媒含有液に、(メタ)アクリル酸エステルと蒸留分離された重質分とが混合された液であり、図1,2における「※2」で示す配管の流通液が該当する。この混合液が重質分解器への全導入液となる。   In the present invention, the acid catalyst-containing liquid refers to a liquid containing an acid catalyst among liquids introduced into the heavy cracker, and is a flowing liquid of liquid extracted from the bottom of the extraction tower 2 in FIG. 1 corresponds to the circulating fluid in the pipe indicated by “* 1” in FIG. Or the distribution | circulation liquid of the piping shown by "* 1" in FIG. 2 corresponds. Moreover, the liquid mixture of the heavy component and the acid catalyst-containing liquid is a liquid in which (meth) acrylic acid ester and the heavy component separated by distillation are mixed with this acid catalyst-containing liquid. This corresponds to the circulating fluid in the pipe indicated by “* 2” in FIG. This mixed liquid becomes the total introduction liquid into the heavy decomposer.

酸触媒含有液とは、酸触媒を含有していればよく、特に制限はないが、通常、図1に示す如く、抽出塔2の塔底から抜き出される酸触媒含有抽出液、或いは、図2における酸触媒の導入液である。   The acid catalyst-containing liquid is not particularly limited as long as it contains an acid catalyst. Usually, the acid catalyst-containing liquid extracted from the bottom of the extraction tower 2 as shown in FIG. 2 is an acid catalyst introduction liquid in No. 2.

酸触媒含有液中の酸触媒濃度が28重量%より高いと、重質分解器7のリボイラー8Aの閉塞トラブルを引き起こし易い。ただし、酸触媒含有液中の酸触媒濃度が低過ぎると、重質分解器における酸触媒量が不足し、重質分の分解、エステル化反応効率が低下するため、酸触媒含有液の酸触媒濃度は、特に5〜28重量%、とりわけ10〜25重量%、中でも10〜20重量%とすることが好ましい。なお、酸触媒含有液の酸触媒濃度が高くても、これに重質分を混合した混合液の酸触媒濃度が低ければ、重質分解器内の酸触媒濃度が抑えられ、リボイラーの閉塞トラブルは抑制される傾向にあるが、混合液の酸触媒濃度が低くても、酸触媒含有液の酸触媒濃度が高過ぎると、やはりリボイラーの閉塞トラブルを引き起こし易い。これは、酸触媒含有液は通常水溶液であるのに対し、その他の液は有機溶剤であるため混合性が悪く、混合液全体に対する濃度が低くとも、重質分解器で水が蒸発した際には局所的に酸触媒が高濃度で存在し、閉塞物形成の要因になるためであると推定される。   If the concentration of the acid catalyst in the acid catalyst-containing liquid is higher than 28% by weight, a trouble of clogging the reboiler 8A of the heavy cracker 7 is likely to occur. However, if the acid catalyst concentration in the acid catalyst-containing liquid is too low, the amount of acid catalyst in the heavy cracker is insufficient, and the decomposition of the heavy component and the esterification reaction efficiency are reduced. The concentration is particularly preferably 5 to 28% by weight, more preferably 10 to 25% by weight, and particularly preferably 10 to 20% by weight. Even if the acid catalyst concentration of the acid catalyst-containing liquid is high, if the acid catalyst concentration of the mixed liquid in which the heavy component is mixed is low, the acid catalyst concentration in the heavy cracker can be suppressed, and the reboiler is blocked. However, even if the acid catalyst concentration of the mixed solution is low, if the acid catalyst concentration of the acid catalyst-containing solution is too high, reboiler clogging trouble is likely to occur. This is because the acid catalyst-containing liquid is usually an aqueous solution, while the other liquids are organic solvents, so the mixing properties are poor, and even when the concentration relative to the whole liquid mixture is low, when the water evaporates in the heavy cracker. It is estimated that this is because the acid catalyst is locally present in a high concentration and becomes a cause of occlusion formation.

また、混合液中の酸触媒濃度が3重量%より高いと、重質分解器7のリボイラー8Aの閉塞トラブルを引き起こし易い。ただし、混合液中の酸触媒濃度が低過ぎると、重質分解器における酸触媒量が不足し、重質分の分解、エステル化反応効率が低下するため、混合液の酸触媒濃度は、特に1〜3重量%、とりわけ1〜2.5重量%、中でも1.5〜2.5重量%とすることが好ましい。なお、混合液の酸触媒濃度が高くても、酸触媒含有液の酸触媒濃度が低ければ、重質分解器に導入される前の酸触媒含有液中での閉塞物原因物質の形成が防止されることにより、リボイラーの閉塞トラブルは抑制される傾向にあるが、前記(1)の条件のみを満たす場合であっても、混合液の酸触媒濃度は3重量%以下であることが好ましい。また、前記(2)の条件のみを満たす場合であっても、酸触媒含有液の酸触媒濃度は28重量%以下であることが好ましい。即ち、上記(1)と(2)の条件をともに満たすように酸触媒濃度を調整することが好ましい。   Further, if the acid catalyst concentration in the mixed solution is higher than 3% by weight, a trouble of clogging the reboiler 8A of the heavy cracker 7 is likely to occur. However, if the acid catalyst concentration in the mixed solution is too low, the amount of acid catalyst in the heavy cracker will be insufficient, and the decomposition of heavy components and the esterification reaction efficiency will decrease. It is preferably 1 to 3% by weight, particularly 1 to 2.5% by weight, and more preferably 1.5 to 2.5% by weight. Even if the acid catalyst concentration of the mixed solution is high, if the acid catalyst concentration of the acid catalyst-containing solution is low, the formation of obstructive substances in the acid catalyst-containing solution before being introduced into the heavy cracker is prevented. As a result, reboiler clogging troubles tend to be suppressed, but even when only the condition (1) is satisfied, the acid catalyst concentration of the mixed solution is preferably 3% by weight or less. Even when only the condition (2) is satisfied, the acid catalyst concentration of the acid catalyst-containing liquid is preferably 28% by weight or less. That is, it is preferable to adjust the acid catalyst concentration so as to satisfy both the above conditions (1) and (2).

この酸触媒濃度の調整は、例えば、図1の製造プロセスの場合、エステル化反応器1への酸触媒供給量を調整したり、抽出塔2の塔底液から別ラインへ液を排出して酸触媒濃度を下げる方法の他、重質分解器への重質分の送給量に対して、回収触媒、(メタ)アクリル酸、及び抜き出し液の送給量を調整する方法や、抽出塔2への水の導入量を調整して抽出塔2からの回収触媒液の酸触媒濃度を調整する方法などが挙げられる。   For example, in the case of the production process shown in FIG. 1, the acid catalyst concentration is adjusted by adjusting the amount of acid catalyst supplied to the esterification reactor 1 or discharging the liquid from the bottom liquid of the extraction tower 2 to another line. In addition to the method of reducing the acid catalyst concentration, the method of adjusting the feed rate of the recovered catalyst, (meth) acrylic acid, and the extracted liquid with respect to the feed amount of heavy components to the heavy cracker, and the extraction tower And a method of adjusting the acid catalyst concentration of the catalyst solution recovered from the extraction tower 2 by adjusting the amount of water introduced into the column 2.

以下に、(メタ)アクリル酸エステルの一般的な製造方法について、図1を参照して説明するが、本発明の(メタ)アクリル酸エステルの製造方法は、図1に示す製造プロセスに限らず、図2に示す製造プロセス、その他、(メタ)アクリル酸とアルコールとを酸触媒の存在下に反応させて得られた(メタ)アクリル酸エステルを含むエステル化反応液から(メタ)アクリル酸エステルと重質分とを蒸留分離し、この重質分を重質分解器に送給して分解、エステル化反応させて有価物を回収する方法に適用することができる。   Below, the general manufacturing method of (meth) acrylic acid ester is demonstrated with reference to FIG. 1, but the manufacturing method of (meth) acrylic acid ester of this invention is not restricted to the manufacturing process shown in FIG. 2, (meth) acrylic acid ester from an esterification reaction solution containing (meth) acrylic acid ester obtained by reacting (meth) acrylic acid and alcohol in the presence of an acid catalyst. And the heavy component can be distilled and separated, and the heavy component can be fed to a heavy decomposer to be decomposed and esterified to recover valuable materials.

本発明で製造される(メタ)アクリル酸エステルとしては、特に限定されず、(メタ)アクリル酸メチル、(メタ)アクリル酸エチル、(メタ)アクリル酸n−ブチル、(メタ)アクリル酸n−ヘキシル、(メタ)アクリル酸n−オクチル、(メタ)アクリル酸2−エチルヘキシル等が挙げられる。これらの中でも(メタ)アクリル酸n−ブチル、(メタ)アクリル酸2−エチルヘキシルなどのアルキル基の炭素数が4以上の(メタ)アクリル酸アルキルエステルが好ましい。   The (meth) acrylic acid ester produced in the present invention is not particularly limited, and is methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, (meth) acrylic acid n-. Examples include hexyl, n-octyl (meth) acrylate, and 2-ethylhexyl (meth) acrylate. Among these, (meth) acrylic acid alkyl esters having 4 or more carbon atoms in the alkyl group such as n-butyl (meth) acrylate and 2-ethylhexyl (meth) acrylate are preferable.

(メタ)アクリル酸エステルの製造では、一般的には(メタ)アクリル酸とアルコールとから酸触媒の存在下、エステル化反応器1を経てエステル化反応させて対応するエステルを製造する。通常原料である(メタ)アクリル酸とアルコールとは、モル比1.0:0.5〜1.0:2.0の割合で反応器に供給される。酸触媒としては、p−トルエンスルホン酸、ベンゼンスルホン酸、キシレンスルホン酸、あるいは、メタンスルホン酸等の有機酸や硫酸、塩酸等の鉱酸が用いられる。酸触媒は反応液に対し、0.1〜5.0重量%、好ましくは1.0〜2.5重量%の割合で添加される。反応は70〜180℃の温度で、蒸留や共沸蒸留によりエステル化反応で生成する反応生成水を除去しながら行われる(反応蒸留方式)。生成水の除去を容易にするために、反応に不活性な共沸剤が添加されることがある。共沸剤としては、ベンゼン、トルエン、シクロヘキサン等の炭化水素が用いられることが多い。反応生成水は蒸気分離膜、ベーパーレイション膜などの膜分離や、蒸留以外の方法で除去される場合もある。   In the production of a (meth) acrylic acid ester, the corresponding ester is generally produced from (meth) acrylic acid and an alcohol through an esterification reactor 1 in the presence of an acid catalyst. Usually, (meth) acrylic acid and alcohol as raw materials are supplied to the reactor at a molar ratio of 1.0: 0.5 to 1.0: 2.0. As the acid catalyst, p-toluenesulfonic acid, benzenesulfonic acid, xylenesulfonic acid, organic acids such as methanesulfonic acid, and mineral acids such as sulfuric acid and hydrochloric acid are used. The acid catalyst is added in an amount of 0.1 to 5.0% by weight, preferably 1.0 to 2.5% by weight, based on the reaction solution. The reaction is carried out at a temperature of 70 to 180 ° C. while removing the reaction product water produced by the esterification reaction by distillation or azeotropic distillation (reactive distillation method). An azeotropic agent inert to the reaction may be added to facilitate removal of product water. As the azeotropic agent, hydrocarbons such as benzene, toluene and cyclohexane are often used. The reaction product water may be removed by a method other than membrane separation such as a vapor separation membrane or a vaporization membrane, or distillation.

また、反応系には、通常、ポリマーの生成を防止するために、重合防止剤が添加される。重合防止剤としては、ハイドロキノン、ハイドロキノンモノメチルエーテル等のフェノール類、フェノチアジン、ジフェニルアミン等のアミン類、ジブチルジチオカルバミン酸銅、酢酸マンガン等の重金属塩、ニトロソ化合物、ニトロ化合物、テトラメチルピペリジノオキシル誘導体等のアミノキシル類が知られている。重合防止剤の添加量は、エステル化反応液中の重合防止剤濃度が20〜1000ppm程度となる量とすることが好ましい。   In addition, a polymerization inhibitor is usually added to the reaction system in order to prevent the formation of a polymer. Examples of polymerization inhibitors include phenols such as hydroquinone and hydroquinone monomethyl ether, amines such as phenothiazine and diphenylamine, heavy metal salts such as copper dibutyldithiocarbamate and manganese acetate, nitroso compounds, nitro compounds, tetramethylpiperidinooxyl derivatives, etc. The aminoxyls are known. The addition amount of the polymerization inhibitor is preferably such that the concentration of the polymerization inhibitor in the esterification reaction solution is about 20 to 1000 ppm.

エステル化反応液は、抽出塔(触媒回収塔)2で水と向流接触して酸触媒が抽出分離、回収され、回収された酸触媒の一部はエステル化反応器1の入口側へ循環され再利用され、残部は後段の重質分解器7に送給され、重質分解器7における重質分の分解に使用される。抽出塔2からの反応液は、アクリル酸分離塔3でアルカリ水溶液が添加されて中和されると共に、水で洗浄された後、アクリル酸分離器3の塔頂から静置槽4に送給されて油水分離される。   The esterification reaction solution is countercurrently contacted with water in the extraction tower (catalyst recovery tower) 2 to extract and recover the acid catalyst, and a part of the recovered acid catalyst is circulated to the inlet side of the esterification reactor 1. Then, the remainder is sent to the heavy decomposer 7 at the subsequent stage, and used for heavy component decomposition in the heavy decomposer 7. The reaction liquid from the extraction tower 2 is neutralized by adding an alkaline aqueous solution in the acrylic acid separation tower 3 and washed with water, and then sent to the stationary tank 4 from the top of the acrylic acid separator 3. The oil and water are separated.

抽出塔2でエステル化反応液と向流接触させる水の比率は、エステル化反応液に対して0.5(重量比)以下が好ましく、最適には0.05〜0.2(重量比)である。水は、新しく添加されても良いが、エステル化反応器1から得られる反応生成水を用いることもでき、この場合には、排水量を少なくすることができる利点がある。   The ratio of water counter-contacted with the esterification reaction liquid in the extraction tower 2 is preferably 0.5 (weight ratio) or less with respect to the esterification reaction liquid, and optimally 0.05 to 0.2 (weight ratio). It is. Although water may be newly added, the reaction product water obtained from the esterification reactor 1 can also be used. In this case, there is an advantage that the amount of waste water can be reduced.

抽出塔2の形式としては、通常のものを用いることができる。一般的な抽出塔は、塔下部よりエステル化反応液、塔上部より抽出用の水を供給し、塔頂より酸触媒などが抽出除去された反応液を、塔底より酸触媒、(メタ)アクリル酸等を含む水溶液を得る型式のものであるが、特に制限されるものではない。抽出塔としては、充填塔、棚段塔などが一般的に用いられるが、液液接触効率の高い装置が好ましい。抽出塔は、一段でも多段に設けてもよい。   As the form of the extraction tower 2, a normal one can be used. A general extraction tower supplies an esterification reaction liquid from the bottom of the tower, extraction water from the top of the tower, and a reaction liquid from which the acid catalyst has been extracted and removed from the top of the tower. Although it is a type which obtains the aqueous solution containing acrylic acid etc., it does not restrict | limit in particular. As the extraction tower, a packed tower, a plate tower and the like are generally used, but an apparatus having a high liquid-liquid contact efficiency is preferable. The extraction tower may be provided in a single stage or multiple stages.

アクリル酸分離塔3としては抽出塔2と同様のものを用いることができる。中和に用いるアルカリ水溶液としては、通常、水酸化ナトリウム、水酸化カリウムなどのアルカリ金属水酸化物の水溶液を挙げることができる。酸性の水溶性不純物を含有するエステル化反応液を中和してこれらの不純物を完全に除去するために、中和後のアクリル酸含有液のpHが9以上となるようにアルカリ水溶液を供給することが好ましい。   As the acrylic acid separation tower 3, the same one as the extraction tower 2 can be used. Examples of the aqueous alkali solution used for neutralization include aqueous solutions of alkali metal hydroxides such as sodium hydroxide and potassium hydroxide. In order to neutralize the esterification reaction liquid containing acidic water-soluble impurities and completely remove these impurities, an alkaline aqueous solution is supplied so that the pH of the neutralized acrylic acid-containing liquid is 9 or more It is preferable.

アクリル酸分離塔3で中和、洗浄して(メタ)アクリル酸等の酸性の水溶性不純物を除去した後のエステル化反応液(以下、「中和・洗浄処理液」と称す場合がある。)は、アクリル酸分離塔3の塔頂から抜き出され、中和、洗浄に用いた水は塔底より排水として系外へ排出される。アクリル酸分離塔3からの中和・洗浄処理液には、中和・洗浄処理液中のアルカリ金属の除去効率を高めるために、更に水が添加される場合もあり、その後静置槽4に送給される。この中和・洗浄処理液への水の添加量は、少な過ぎるとアルカリ金属の除去効率の向上効果を十分に得ることができず、多過ぎてもそれ以上の効果の向上は望めず、徒に液量が増大して工業的に不利である。従って、添加する水の量は、中和・洗浄処理液に対して通常、0〜100重量%、好ましくは1〜10重量%、更に好ましくは2〜6重量%である。   An esterification reaction liquid (hereinafter referred to as “neutralization / washing treatment liquid”) after neutralization and washing in the acrylic acid separation tower 3 to remove acidic water-soluble impurities such as (meth) acrylic acid. ) Is extracted from the top of the acrylic acid separation tower 3, and the water used for neutralization and washing is discharged out of the system as waste water from the bottom of the tower. Water may be further added to the neutralization / washing treatment liquid from the acrylic acid separation tower 3 in order to increase the removal efficiency of alkali metals in the neutralization / washing treatment liquid. Be sent. If the amount of water added to the neutralization / cleaning solution is too small, the effect of improving the alkali metal removal efficiency cannot be sufficiently obtained, and if it is too large, no further improvement in effect can be expected. However, it is industrially disadvantageous because the liquid volume increases. Accordingly, the amount of water to be added is usually 0 to 100% by weight, preferably 1 to 10% by weight, and more preferably 2 to 6% by weight with respect to the neutralization / cleaning treatment liquid.

中和・洗浄処理液に添加する水は、金属成分などの新たな汚染源となるものを高濃度に含まないものであれば良く、工水、純水、蒸気凝縮水などを用いることができる。   The water to be added to the neutralization / cleaning treatment liquid may be any water that does not contain a high concentration of a new contamination source such as a metal component, and industrial water, pure water, steam condensed water, or the like can be used.

必要に応じて水が添加された中和・洗浄処理液は、次いで静置槽4で静置されて油水分離され、水相は排水として系外へ排出され、油相は軽沸分離塔5に送給されてアルコール等の軽沸分が塔頂より蒸留分離され、塔頂留出物は反応器1へ循環される。一方、塔底液は更に精製塔6で高沸分が蒸留分離され、塔頂より製品のアクリル酸エステルが分離される。   The neutralization / cleaning treatment liquid to which water is added as necessary is then left in the stationary tank 4 to be separated into oil and water, the aqueous phase is discharged out of the system as waste water, and the oil phase is light boiling separation tower 5 The light boiling components such as alcohol are distilled and separated from the top of the column, and the top distillate is circulated to the reactor 1. On the other hand, the high-boiling fraction of the column bottom liquid is further separated by distillation in the purification column 6, and the product acrylic acid ester is separated from the column top.

精製塔6の塔底液は、抽出塔2からの回収触媒(回収触媒を含む抽出液)、原料タンクからのアクリル酸、必要に応じてプロセス外抜き出し液との混合液からなる酸触媒含有液と混合されて重質分解器7に導入され、重質分中のミカエル付加物等が分解、エステル化反応され、アクリル酸アルキル、アルコール、アクリル酸等を含む有価物が塔頂より抜き出される。この有価物はエステル化反応器1又はアクリル酸分離塔3に返送される。一方、重質分解器7の塔底液は廃油として系外へ排出される。   The column bottom liquid of the purification tower 6 is an acid catalyst-containing liquid consisting of a mixture of a recovered catalyst from the extraction tower 2 (an extract containing the recovered catalyst), acrylic acid from the raw material tank, and, if necessary, a liquid extracted from outside the process. And mixed into the heavy cracker 7, where the Michael adducts in the heavy component are decomposed and esterified, and valuable materials including alkyl acrylate, alcohol, acrylic acid, etc. are extracted from the top of the column. . This valuable material is returned to the esterification reactor 1 or the acrylic acid separation column 3. On the other hand, the bottom liquid of the heavy cracker 7 is discharged out of the system as waste oil.

この重質分解器7の運転条件については特に制限はないが、通常、反応温度150〜200℃、反応圧力90〜100kPaが採用される。また、廃油として抜き出す塔底液の量にも特に制限はないが、通常、重質分解器7に導入される混合液に対して10〜40重量%程度の条件とすることが好ましい。   Although there is no restriction | limiting in particular about the operating conditions of this heavy decomposer 7, Usually, reaction temperature 150-200 degreeC and reaction pressure 90-100 kPa are employ | adopted. Moreover, although there is no restriction | limiting in particular in the quantity of the tower bottom liquid extracted as waste oil, Usually, it is preferable to set it as about 10-40 weight% conditions with respect to the liquid mixture introduce | transduced into the heavy cracker 7. FIG.

なお、図1では、エステル化反応液を抽出塔2、アクリル酸分離塔3、静置槽4、軽沸分離塔5、精製塔6で順次処理して得られた精製塔6の塔底液である重質分を重質分解器7で分解しているが、本発明で重質分解器において分解する重質分は、エステル化反応液から(メタ)アクリル酸エステルと蒸留分離された重質分であればよく、何ら図1に示される処理を経たものに限定されない。   In FIG. 1, the bottom liquid of the purification tower 6 obtained by sequentially treating the esterification reaction liquid in the extraction tower 2, the acrylic acid separation tower 3, the stationary tank 4, the light boiling separation tower 5, and the purification tower 6. Is decomposed by the heavy decomposer 7, but the heavy component decomposed in the heavy decomposer in the present invention is separated from the (meth) acrylic acid ester by distillation from the esterification reaction solution. What is necessary is just a mass, and it is not limited to what passed through the process shown by FIG.

以下に実施例を挙げて本発明をより具体的に説明する。   Hereinafter, the present invention will be described more specifically with reference to examples.

なお、以下において、アクリル酸ブチル、n−ブタノール、ブトキシプロピオン酸ブチル等の濃度はガスクロマトグラフィーにより測定した。   In the following, the concentrations of butyl acrylate, n-butanol, butyl butoxypropionate and the like were measured by gas chromatography.

[実施例1]
図1に示すアクリル酸ブチルの製造プロセスにおいて、精製塔6から得られた塔底液と、抽出塔2からの回収触媒液と、原料タンクからのアクリル酸とを重質分解器7に送給して重質分の分解、エステル化反応を行った。精製塔6の塔底液の組成は以下の通りであり、塔底液は820kg/hrで重質分解器7に導入した。また、抽出塔2からの回収触媒液の組成は以下の通りであり、回収触媒液は110kg/hrで重質分解器7に導入し、アクリル酸は110kg/hrで重質分解器7に導入した。
[Example 1]
In the butyl acrylate manufacturing process shown in FIG. 1, the bottom liquid obtained from the purification tower 6, the recovered catalyst liquid from the extraction tower 2, and acrylic acid from the raw material tank are fed to the heavy cracker 7. Then, the heavy component was decomposed and esterified. The composition of the bottom liquid of the purification tower 6 is as follows, and the bottom liquid was introduced into the heavy cracker 7 at 820 kg / hr. The composition of the recovered catalyst solution from the extraction tower 2 is as follows. The recovered catalyst solution is introduced into the heavy cracker 7 at 110 kg / hr, and acrylic acid is introduced into the heavy cracker 7 at 110 kg / hr. did.

<塔底液組成>
アクリル酸ブチル:41重量%
ブトキシプロピオン酸ブチル:48重量%
ヒドロキシプロピオン酸ブチル:1重量%
ダイマー酸ブチル:4重量%
マレイン酸ジブチル:5重量%
<回収触媒液組成>
水:75重量%
ブタノール:3重量%
p−トルエンスルホン酸:18重量%
<Tower liquid composition>
Butyl acrylate: 41% by weight
Butyl propionate butyl: 48% by weight
Butyl hydroxypropionate: 1% by weight
Dimeric acid butyl: 4% by weight
Dibutyl maleate: 5% by weight
<Recovered catalyst solution composition>
Water: 75% by weight
Butanol: 3% by weight
p-Toluenesulfonic acid: 18% by weight

即ち、酸触媒含有液の酸触媒濃度は18重量%で、混合液の酸触媒濃度は1.9重量%である。
重質分解器は反応温度170℃、反応圧力100kPa、塔底液抜出量240kg/hrで運転し、塔頂留出物はエステル化反応器1に循環した。
この結果、90日間、重質分解器7のリボイラー7Aの閉塞トラブルを引き起こすことなく安定に連続運転することができた。
That is, the acid catalyst concentration of the acid catalyst-containing liquid is 18% by weight, and the acid catalyst concentration of the mixed liquid is 1.9% by weight.
The heavy cracker was operated at a reaction temperature of 170 ° C., a reaction pressure of 100 kPa, and a column bottom liquid discharge rate of 240 kg / hr, and the column top distillate was circulated to the esterification reactor 1.
As a result, the continuous operation could be stably performed for 90 days without causing the trouble of the reboiler 7A of the heavy cracker 7 being blocked.

[比較例1]
実施例1において、エステル化反応器1への酸触媒供給量を変更し、酸触媒含有液(回収触媒)の酸触媒(p−トルエンスルホン酸)濃度を30重量%、混合液の酸触媒濃度を3.5重量%として運転を行ったところ、運転開始から15日間で重質分解器7のリボイラー7Aの閉塞トラブルにより運転停止となった。
[Comparative Example 1]
In Example 1, the acid catalyst supply amount to the esterification reactor 1 was changed, the acid catalyst (p-toluenesulfonic acid) concentration of the acid catalyst-containing liquid (recovered catalyst) was 30% by weight, and the acid catalyst concentration of the mixed liquid When the operation was performed at 3.5% by weight, the operation was stopped due to a clogging trouble of the reboiler 7A of the heavy cracker 7 within 15 days from the start of the operation.

1 エステル化反応器
2 抽出塔
3 アクリル酸分離塔
4 静置槽
5 軽沸分離塔
6 精製塔
7 重質分解器
7A リボイラー
8 溶媒回収塔
DESCRIPTION OF SYMBOLS 1 Esterification reactor 2 Extraction tower 3 Acrylic acid separation tower 4 Standing tank 5 Light boiling separation tower 6 Purification tower 7 Heavy cracker 7A Reboiler 8 Solvent recovery tower

Claims (5)

(メタ)アクリル酸とアルコールとを酸触媒の存在下に反応させて(メタ)アクリル酸エステルを含むエステル化反応液を得る反応工程と、該エステル化反応液から(メタ)アクリル酸エステルと重質分とを蒸留分離する精製工程と、該重質分を酸触媒含有液との混合液として重質分解器に導入して分解、エステル化反応させることにより(メタ)アクリル酸エステル及びアルコールを含む有価物を回収する回収工程とを含む(メタ)アクリル酸エステルの製造方法において、下記(1)及び/又は(2)の条件を満たすことを特徴とする(メタ)アクリル酸エステルの製造方法。
(1) 前記酸触媒含有液の酸触媒濃度が5〜28重量
(2) 前記混合液の酸触媒濃度が1〜3重量%
A reaction step of reacting (meth) acrylic acid and alcohol in the presence of an acid catalyst to obtain an esterification reaction liquid containing (meth) acrylic acid ester; and (meth) acrylic acid ester and The (meth) acrylic acid ester and alcohol are purified by introducing the heavy component into a heavy decomposer as a mixed solution with an acid catalyst-containing liquid and decomposing and esterifying it. A method for producing a (meth) acrylic acid ester, which satisfies the following conditions (1) and / or (2): .
(1) The acid catalyst concentration of the acid catalyst-containing liquid is 5 to 28 % by weight .
(2) The acid catalyst concentration of the mixed solution is 1 to 3% by weight.
前記酸触媒含有液の酸触媒濃度が10〜25重量%で、前記混合液の酸触媒濃度が1〜2.5重量%であることを特徴とする請求項1に記載の(メタ)アクリル酸エステルの製造方法。   2. The (meth) acrylic acid according to claim 1, wherein the acid catalyst concentration of the acid catalyst-containing liquid is 10 to 25 wt%, and the acid catalyst concentration of the mixture is 1 to 2.5 wt%. Ester production method. 前記エステル化反応液中の酸触媒を水で抽出して回収する抽出工程を含み、前記混合液は、該抽出工程からの酸触媒含有液と原料(メタ)アクリル酸を含むことを特徴とする請求項1又は2に記載の(メタ)アクリル酸エステルの製造方法。   Including an extraction step of extracting and recovering the acid catalyst in the esterification reaction solution with water, wherein the mixed solution contains an acid catalyst-containing solution from the extraction step and a raw material (meth) acrylic acid. The manufacturing method of the (meth) acrylic acid ester of Claim 1 or 2. 前記有価物を前記反応工程に返送する返送工程を含むことを特徴とする請求項1ないし3のいずれか1項に記載の(メタ)アクリル酸エステルの製造方法。   The method for producing a (meth) acrylic acid ester according to any one of claims 1 to 3, further comprising a returning step of returning the valuable material to the reaction step. 前記重質分解器の塔頂より前記有価物を回収し、前記重質分解器の塔底液を廃油として系外に排出する(メタ)アクリル酸エステルの製造方法であって、該重質分解器に導入される前記混合液に対する該廃油の割合が10〜40重量%であることを特徴とする請求項1ないし4のいずれか1項に記載の(メタ)アクリル酸エステルの製造方法。   A method for producing a (meth) acrylic acid ester, wherein the valuable material is recovered from the top of the heavy cracker, and the bottom liquid of the heavy cracker is discharged as waste oil to the outside of the system. The method for producing a (meth) acrylic acid ester according to any one of claims 1 to 4, wherein a ratio of the waste oil to the mixed liquid introduced into the vessel is 10 to 40% by weight.
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