201223939 六、發明說明： 【發明所屬之技術領域】 本發明係關於在丙烯酸酯、較佳為高沸點的丙烯酸 醋之製造中’以反應中所生成的丙烯酸之回收·再使用 為主要目的的丙稀酸酯之製造方法、及丙稀酸之回收方 法’屬於製造•使用丙烯酸酯之技術領域及使用丙烯酸 之技術領域。 【先前技術】 丙烯酸酯係大多在酸觸媒的存在下使丙烯酸與醇進 行酯化反應所製造。 在低沸點丙烯酸酯之製造中，蒸餾反應液以進行精 製。 另外，在高沸點丙烯酸酯之製造中由於蒸餾不易， 故中和包含反應溶劑的酯化反應液以除去酸觸媒及丙烯 酸’分離有機相與水相之已2層分離的有機層，再者使 有機層中的反應溶劑進行去溶劑所製造。此時，由於其 為目的物之丙烯酸酯與原料醇的分離困難，一般採用如 使用過剩丙烯酸而使原料醇儘可能多地反應，而在反應 液中未殘留醇的方法。 然而’使用過剩丙烯酸時，則產生進行除去丙烯酸 的中和•水洗之必要’該結果不僅損失丙稀酸，亦包含 產生化學需氧量（COD)値高的廢水之問題。 為了解決上述的問題’提案中和酯化反應液，使含 有丙烯酸或其驗金屬鹽的水性溶液進行酸性化，藉由有 機溶劑萃取回收丙烯酸之方法（專利文獻1及2)。 201223939 然而’該等方法係因以有機溶劑萃取回收，變得必 須有用於進行萃取之設備、用於回收有機溶劑之設備， 而回收液中的丙烯酸濃度低如3 0重量％以下，在再利用 所回收的丙烯酸中則必須藉由蒸餾等進行精製等處於不 一定足夠的情況。 先前技術文獻 專利文獻 專利文獻1 特開2006-213647號公報 專利文獻2 特開昭61-243046號公報 【發明内容】 [發明的概要] [發明所欲解決之課題] 本發明之目的為提供不需要藉由有機溶劑的丙婦酸 之萃取步驟、回收液中的丙烯酸濃度為高濃度、丙烯酸 之回收效率優異的丙烯酸酯之製造方法，及丙烯酸之回 收方法。 [用以解決課題之方式] 本發明者等為了解決前述課題而進行專心一志研究 的結果，完成以下所示之本發明的丙烯酸酯之製造方 法、及丙烯酸之回收方法。 以依次實施下述第1步驟至第5步驟為特徵的丙烯 酸曄之製造方法。 第1步驟：在酸觸媒的存在下，攪拌•混合丙烯酸 與醇，獲得已進行酯化反應之包含丙烯酸酯的反應液之 步驟； 201223939 第2步驟：添加鹼水溶液於第1步驟中所獲得之反 應液以中和後’分離為有機相與水相之2相，分餾有機 相，回收丙烯酸酯之步驟； 第3步驟：分餾於第2步驟所獲得之水相，添加碳 酸濃度為70重量％以上的硫酸水溶液於其中，調整 於4.0以下，且使液體中之丙烯酸及/或其鹼金屬鹽的含 有比例以丙稀酸換算為1 8重量％以上之步驟； 第4步驟：將於第3步驟所獲得的液體分離成大多 包含丙烯酸及/或其鹼金屬鹽之相（上層）、與大多包含硫 酸鹼金屬鹽之相（下層）之2相之步驟； 第5步驟：分餾於第4步驟所獲得之液體的大多包 含硫酸鹼金屬鹽之相（下層），回收殘留的大多包含丙稀 酸及/或其鹼金屬鹽之相（上層）之步驟。 以依次實施下述第3’步驟至第5，步驟為特徵的丙烯 酸之回收方法。 第3’步驟：調製含有丙烯酸及/或其鹼金屬鹽、硫酸 驗金屬鹽、以及水，pH為4.0以下，且丙稀酸及/或其驗201223939 VI. Description of the Invention: [Technical Field] The present invention relates to a main purpose of recycling and reusing acrylic acid produced in a reaction in the production of an acrylate, preferably a high-boiling acrylic vinegar. The method for producing a dilute acid ester and the method for recovering acrylic acid are in the technical field of manufacturing and using acrylate and the technical field using acrylic acid. [Prior Art] Acrylates are often produced by esterification of acrylic acid with an alcohol in the presence of an acid catalyst. In the production of a low boiling point acrylate, the reaction liquid is distilled to be refined. In addition, in the production of high-boiling acrylates, it is difficult to distill, so the esterification reaction solution containing the reaction solvent is neutralized to remove the acid catalyst and the organic layer of the acrylic acid separated from the organic phase and the aqueous phase. The reaction solvent in the organic layer is subjected to solvent removal. At this time, since it is difficult to separate the acrylate of the target from the raw material alcohol, a method in which the raw material alcohol is reacted as much as possible, and the alcohol is not left in the reaction liquid, is generally employed. However, when excessive acrylic acid is used, it is necessary to carry out neutralization and water washing for removing acrylic acid. This result not only causes loss of acrylic acid but also causes generation of waste water having a high chemical oxygen demand (COD). In order to solve the above problem, a method of neutralizing an esterification reaction liquid, acidizing an aqueous solution containing acrylic acid or a metal salt thereof, and recovering acrylic acid by organic solvent extraction (Patent Documents 1 and 2) is proposed. 201223939 However, 'these methods are extracted by organic solvent extraction, and it is necessary to have equipment for extracting and equipment for recovering organic solvents, and the concentration of acrylic acid in the recovered liquid is as low as 30% by weight or less, and is reused. In the acrylic acid to be recovered, it is not necessarily sufficient to carry out purification by distillation or the like. [Problems to be Solved by the Invention] [The object of the present invention] The object of the present invention is to provide no There is a need for an extraction process of a bupropion acid by an organic solvent, a method of producing an acrylate having a high concentration of acrylic acid in a recovered liquid, and an excellent recovery efficiency of acrylic acid, and a method for recovering acrylic acid. [Means for Solving the Problem] The inventors of the present invention have completed the results of intensive research to solve the above problems, and have completed the method for producing an acrylate of the present invention and the method for recovering acrylic acid described below. A method for producing bismuth acrylate characterized by sequentially performing the following first to fifth steps. Step 1 : a step of stirring and mixing acrylic acid and alcohol in the presence of an acid catalyst to obtain a reaction liquid containing an acrylate which has been subjected to an esterification reaction; 201223939 second step: adding an aqueous alkali solution in the first step The reaction liquid is separated into two phases of an organic phase and an aqueous phase after neutralization, fractionating the organic phase, and recovering the acrylate. Step 3: fractionating the aqueous phase obtained in the second step, adding a carbonic acid concentration of 70% by weight And a step of adjusting the ratio of the content of the acrylic acid and/or the alkali metal salt thereof in the liquid to 18% by weight or more in terms of acrylic acid; the fourth step: The liquid obtained in the third step is separated into a phase in which a phase containing most of acrylic acid and/or an alkali metal salt thereof (upper layer) and a phase containing a large amount of an alkali metal sulfate (lower layer) are separated; Step 5: fractionation in the fourth step Most of the liquid obtained in the step contains a phase (lower layer) of an alkali metal sulfate, and a step of recovering a phase (upper layer) mostly containing acrylic acid and/or an alkali metal salt thereof is recovered. The method for recovering acrylic acid characterized by the steps 3 to 5 described below is carried out in sequence. Step 3: Preparation of acrylic acid and/or its alkali metal salt, sulfuric acid metal salt, and water, pH 4.0 or less, and acrylic acid and/or its test
金屬鹽的含有比例以丙烯酸換篡A ” 佚异马1 8重量％以上之液體 之步驟； 第4’步驟··分離於第3’步驟所獲得的液體成大多包 含丙烯酸及/或其驗金屬鹽之相(上層）、與大多包含硫酸 鹼金屬鹽之相（下層）之2相之步驟； 之液體的大多包 的大多包含丙歸 第5’步驟：分餾於第4,步驟所獲得 含硫isc驗金屬鹽之相（下層），回收殘留 酸及/或其鹼金屬鹽之相（上層）之步驟。 -6 - 201223939 [發明之致果] 根據本發明’可提供不需要藉由有機溶劑的丙烯酸 之萃取步驟’以所謂除去已2相分離的下層液體之簡便 方法可容易地回收丙烯酸’而且可使回收液中的丙烯酸 濃度成為高濃度、回收效率優異的丙烯酸酯之製造方 法、及丙烯酸之回收方法。 又’所回收之丙烯酸係可直接或進行精製後，再使 用於丙烯酸酯或聚合物的製造。 【實施方式] [用以實施發明之形態] 以下’詳細說明本發明。 本發明係關於以依次實施下述第1步驟至第5步驟 為特徵的丙烯酸酯之製造方法。 第1步驟：在酸觸媒的存在下，攪拌•混合丙烯酸 與醇，獲得已進行酯化反應的包含丙烯酸酯之反應液之 步驟； ’ 第2步驟：添加鹼水溶液於第丨步驟中所獲得的反 應液以中和後，分離成有機相與水相之2相，分餾有機 相’回收丙烤酸酯之步驟； 第3步驟：分餾於第2步驟所獲得的水相，添加硫 酸濃度為70重量％以上的硫酸水溶液於其中，調整pH 於4.0以下’而且使液體十的丙烯酸及/或其鹼金屬鹽： 含有比例以丙烯酸換算為18重量％以上之步驟；孤 第4步驟：分離於第3步驟所獲得之液體成為大夕 包含丙烯酸及/或其鹼金屬鹽之相（上層）、與大多包人= 酸驗金屬鹽之相（下層）之2相之步驟； 201223939 第5步驟：分餾於第4步驟所獲得之液體的大多包 含硫酸鹼金屬鹽之相（下層）’回收殘留的大多包含丙稀 酸及/或其鹼金屬鹽之相（上層）之步驟。 又，本發明係關於以依次實施下述第3，步驟至第5 ’ 步驟為特徵的丙烯酸之回收方法。 第3,步驟：調製含有丙烯酸及/或其鹼金屬鹽、硫酸 鹼金屬鹽、以及水，PH為4.0以下，且丙烯酸及/或其驗 金屬鹽的含有比例以丙稀酸換算為1 8重量％以上之液體 之步驟； 第4,步驟：分離於第3’步驟所獲得之液體為大多包 含丙烯酸及/或其鹼金屬鹽之相（上層）、與大多包含硫酸 鹼金屬鹽之相（下層）之2相之步驟； 第5’步驟：分餾於第4’步驟所獲得之液體的大多包 含硫酸鹼金屬鹽之相（下層），回收殘留的大多包含丙烯 酸及/或其驗金屬鹽之相（上層）之步驟。 (丙烯酸酯之製造方法） 根據本發明的丙烯酸酯之製造方法，可製造各種的 丙烯酸酯，可較佳地適用於高沸點丙烯酸酯的製造，特 別是可較佳地適用於在13.3kPa的壓力下之沸點為100 °C以上的丙烯酸酯之製造。 13.3kPa的壓力下之沸點為1〇〇。(：以上的丙烯酸酯方 面’舉例為酚環氧烷加成物的丙烯酸酯、壬酚環氧烷加 成物的丙烯酸酯及對@香基酚環氧烷加成物的丙烯酸酯 專的酚類之環氡炫加成物的丙烯酸酯； 2 -乙基己醇環氧烷加成物的丙烯酸酯； • 8 - 201223939 三環癸二羥曱基的丙烯酸酯等之丙烯酸多環式烷 酯； 二丙烯酸三環癸二經曱酯等的二丙烯酸多環式烷 酯； 乙二醇的一或二丙烯酸酯、丙二醇的一或二丙烯 酯、戊二醇的一或二丙烯酸酯及己二醇的一或二丙烯 酯等的烯烴基二醇之一或二丙烯酸酯； 二乙二醇的一或二丙烯酸酯、三乙二醇的一或二 烯酸酯、四乙二醇的一或二丙烯酸酯、聚乙二醇的一 二丙烯酸酯、二丙二醇的一或二丙烯酸酯、三丙二醇 一或二丙烯酸酯及聚丙二醇的一或二丙烯酸酯等的聚 烴基二醇之一或二丙烯酸酯； 丙三醇的二或三丙烯酸酯及二丙三醇的二或三丙 酸酯等的丙三醇類之二或三丙烯酸酯；丙三醇類的環 烷加成物的二或三丙烯酸酯； 雙酚A環氧烷加成物的一或二丙烯酸酯及雙酚F 氧烧加成物的一或二丙烯酸I旨等的雙盼環氧院加成物 一或二丙烯酸酯； 三羥甲基丙烷三丙烯酸酯、二三羥曱基丙烷三丙 酸酯、二三羥甲基丙烷四丙烯酸酯、新戊四醇三丙烯 酯、新戊四醇四丙烯酸酯、二新戊四醇五（曱基）丙烯 酯及二新戊四醇六丙烯酸酯等的聚醇聚丙烯酸酯；該 聚醇的環氧烷加成物之聚（曱基）丙烯酸酯； 異三聚氰酸環氧烷加成物的二或三（曱基）丙烯 酯； 基 基 酸 酸 丙 或 的 稀 烯 氧 環 之 烯 酸 酸 等 酸 -9 - 201223939 以及聚酯丙烯酸酯等。 環氧院加成物中的環氧烧方面，舉出為環氧乙烧及 環氧丙烷等。又’環氧烷的加成數方面，較佳為丨至2〇。 在該等丙烯酸酯中，在以後述的第i步驟中可防止 水相側溶解丙烯酸酯的觀點來看，比較於烯烴基二醇的 一或二丙烯酸酯等的親水性丙烯酸酯，較適於疏水性的 丙稀酸酯之製造方法。 以下’說明前述的第1步驟至第5步驟。 1.第1步驟 在第1步驟中，在酸觸媒的存在下，擾拌•混合丙 烯酸與醇，獲得已進行酯化反應的包含丙烯酸酯之反應 液。 醋化反應方面，可依照常用方法，舉例為在有機溶 劑中、酸觸媒的存在下加熱•攪拌丙烯酸及高沸點醇的 方法等》 醇方面’可使用對應於前述的丙烯酸酯者。 具體而言，舉出為： 紛基環氧烷加成物、壬酚基環氧烷加成物及對茴香 基酴環氧烷加成物等的酚類之環氧烷加成物； 2 -乙基己醇環氧烷加成物； 三環癸二羥甲基等的多環式烷基醇； 三環癸二羥甲基等的多環式烷基二醇； 乙二醇、丙二醇、戊二醇及己二醇等的烯烴基二醇； 一乙一醇、三乙二醇、四乙二醇、聚乙二醇、二丙 二醇、三丙二醇及聚丙二醇等的聚烯烴基二醇； -10* 201223939 丙三醇及二丙三醇等的丙三醇類； 丙三醇類的環氧烷加成物； 雙酚A環氧烷加成物及雙酚F環氧烷加成物等的雙 盼類環氧烷加成物； 一羥甲基丙烷、二三羥甲基丙烷三丙烯酸酯、新戊 四醇三丙烯酸酯及二新戊四醇等的聚醇； 該等聚醇的環氧烷加成物； 異三聚氰酸環氧烷加成物；以及聚醋聚醇等。 環氧烷加成物中的環氧烷方面，舉例為環氧乙烷及 環氧丙烷等。又，環氧烷的加成數方面，較佳為1至2〇。 該等醇之中，如前述，較佳為使所獲得的丙烯酸酯 成為疏水性之醇。 丙稀酸的使用比例可隨目的丙烯酸酯而適宜地設 定，相對於1莫耳的高沸點醇之全部羥基，較佳為1〇 至2.0莫耳’更佳為1丨至1.5莫耳。 酸觸媒方面’舉出為硫酸等的無機酸、以及對甲笨 續酸、甲績酸及三氟甲續酸等的續酸等。 酸觸媒的使用比例方面’相對於包含有機溶劑的反 應液重量，較佳為〇. 1至10重量％。 酯化反應係可依照常用方法實施。 反應溫度雖隨所使用的原料及目的而適宜地設定， 但從反應時間的縮短與防止聚合的觀點來看，較佳為65 至140°C ’更佳為75至120°C。藉由使反應溫度為65〇c 以上，可迅速地進行酯化反應’並防止產率的降低，另 外使反應溫度為140。(：以下’可防止丙烯酸或所生成的 丙烯酸酯之熱聚合。 201223939 反應令的壓力方面， 以防止丙烯酸或所生成的丙烯酸:旨：：均可。如後述， 佳為在減壓狀態下進行。 之熱聚合為目的，較 在酿化反應時，較佳為使 與有機溶劑共沸同時促進脫水。 所生成的水 較佳的有機溶劑方面’舉例“ 的芳香族烴；己烷及庚烷等的：：本及二甲笨等 的脂環式烴等。 、空，以及環已烷等 有機溶劑的使用量，相對 ^ 量’較佳A；則述醇與丙烯酸的八丄 較佳為成為10至75重量％ 的S叶 至55重量❹/。的比例。 更佳為成為15 s曰化反應係以防止丙烯酸或 聚合為目的，較佳為在75$ μ。成的丙烯醆酯之熱 衩佳為在75至12〇t下進 止聚合’較佳為在氧的存在 為了防 、 〇牡乳旳存在下進行酯化反應。 =同樣的目的，較佳為添加聚合抑制劑於反 中。聚合抑制劑方面，舉例為有 〜液 平灼馮百機化合物及金屬鹽等。 有機化合物方面，舉例盔贫 一 举例為本醌、氫醌、鄰笨二酚、 =級；：醌、氳醌一甲基醚、萘醌、三級丁鄰笨二酚、 本酚、一〒基三級丁苯酚、三級丁 ▼苯酚、二 土羥基节笨及啡噻听（phen〇thiazine)等。 人金屬鹽方面，舉出為氣化銅及硫酸銅等的金屬銅化 5物以及硫酸亞鐵等的金屬鐵化合物等。 聚合抑制劑的添加量隨原料的丙烯酸之使用量以 重量較佳為10至50,000 ppm，更佳為1〇〇至1〇〇〇〇 PPm。在100 ppm以上時則可充份發揮聚合防止效果， -12- 201223939 在10,000 ppm以下時，可一方面防止著色，一方面防止 生成物的硬化性降低。 酯化反應的進行度係一方面監控因酯化反應所生成 的水量，即脫水量，一方面分析反應液中的酸成分濃度， 分析生成物丙稀酸醋的組成以確s忍目的之組成以判斷。 又’前述之氧存在下的反應方面，具體而言為一方 面在含氧氣體的氣體環境下進行反摩，一方面將含氧氣 體導入反應液中同時進行反應的方法。典型的含氧氣體 j為二氣，但在工業上考量閃燃爆炸危險而適合使用氧 3 i 15容量％以下的氣體。含氧氣體係可藉由混 空氣與惰性氣體所調製。惰性氣體方面，常用 氮氣或氬氣。 2.第2步驟 第2步驟係添加鹼水溶 應液以巾*後，*料離成有機 4巾所獲得的反 相’回收丙烯酸醋的步驟。相、水相的2相之有機 以鹼水溶液添加於第丨 藉由驗水溶液從反應驟中所獲得的反應液，可 的酸成分。 刀 •除去丙烯酸及酸觸媒等 在使用於中和的鹼水溶 氮氧化納及氣氧化鉀等的驗驗成分方面，舉出為 等的驗金屬鹽及氮氧虱氧化物、以及碳酸納 中，驗金屬氣氧化物因=的驗土族金屬等。該等之 鹼水溶液中的鹼成八效果向的觀點而為較佳者。 分，較佳為以莫耳 刀之量，相對於反應液的酸成 若為上述範圍時，則充it二更佳為丨…… 進仃S久成分的中和。 -13- 201223939 又’驗水溶液的濃度較佳為i至25重量％，更佳為 3至25重量％ ’特佳為10至25重量％。藉由使該濃度 為1重量％以上，可防止中和處理後的排水量增大；為 2 5重量/〇以下，則可防止丙烯酸酯聚合。 第2 ^驟的中和處理係供給反應液及驗水溶液於槽 型裝置並攪拌以進行處冑，或使用靜態混合器(static mixer)等以進行處理。尚且，因比重調整等的目的，亦 可在中和前添加有機溶劑於反應液中。 在第2步驟中，添加鹼水溶液於第丨步騍所獲得的 反應液以中和後’分離成有機相與水相之2相。亦可分 成夕數次以貫施該中和處理。 _前處理 在實施中和處理之前， 的水洗處理。 因各種目的而可進行反應液 之聚合抑制劑時，可 特佳為在酯化反應中使用銅系 有效率地除去銅系之聚合抑制劑。 ，具體舉出 進行攪拌及 水洗處理的方法方面，可依照常用方法 為添加水於因醋化反應所獲得的反應液中， 混合的方法。 水方面較佳為使用純水。 •丙烯酸酯最終製品 ^第2步驟中，，前述中和處理後，分離成有機相 與水相之2相’分備有機相，回收丙烯酸雖。 有機相的分顧方法方面’可抽取下層二水相。所抽 取的水相係實施後述的第3步驟。 201223939 前述中分餾水相後的有機層，必要時可除去有機溶 劑而成為最終製品的丙稀酸g旨。 去溶劑處理係可依照常用方法進行，舉例為使去溶 劑槽減壓以除去有機溶劑的方法等。去溶劑槽的真空度 方面，可隨所使用的原料及目的而適宜地設定，較22 0.5至50kPa ’較佳為隨溶劑的除去程度而慢慢地增加 壓度。 ' 該去溶劑處理係為了抑制丙烯酸酯的熱聚合，較佳 為方面供給氧，一方面添加聚合抑制劑 例如抓以上8。。。以下，並在減壓下進行。 度於 必要時，亦可在前述去溶劑處理中於去溶劑槽從有 機相除去有機溶劑，同時供給過滤助劑於去溶劑槽，在 連接於去溶劑槽的g型水平濾板式之過濾器中堆積過濾 助劑以進行反應生成物的過濾處理。 一 又，有機層於必要時亦可在進行去溶劑處理之前， 進行水洗處理。 3·第3步驟 第3步驟係分館於第2步驟所獲得的水相（以下，稱 為水相⑺。）’添加硫酸濃度為7〇重量％以上的硫酸水 溶液於其中，調整pH力4.〇以下，而且液體中的丙稀酸 及/或其驗金屬鹽的含有比例以丙烯酸換算A 18重量％ 以上之步驟。 〇 '使用於第3步驟的硫酸水溶液之硫酸濃度為重量 '上右使用小於70重量％者時，第4步驟的2相分 離變困難’使丙浠酸（鹽）的回收率降低。硫酸水溶液的 201223939 又較佳為1 〇 〇重 硫酸濃度方面，較佳為75重量％以上 量％以下’更佳為99重量❶/。以下。 、 3步驟中，添加硫酸水溶液於水相 成為4.0以下。若pH為超過4 ，^ ^ ^ ^ ^ ^ ^ 舱織m他 了弟4步驟的2相分 離變困難’使丙稀酸(鹽)的回收率降低。較佳的水相之 PH方面為0至4.0的範圍’更佳為U 35的範圍。 添加於水相（2)的硫酸水溶液之添加量方面，則為任 何使水相的pH成為4·〇以下之量。 添加硫酸水溶液於水相（2)時的溫度方面，較佳為25 。匚以上，更佳為25至4(TC ’特佳為3〇至4〇t。藉由使 該溫度成為25t：以上，可在第3步中驟防止硫酸鹽3析出。 在本發明的丙烯酸酯之製造方法中，在第3步驟 中，使液體中的丙烯酸及/或其鹼金屬鹽（以下，稱為「丙 烯酸（鹽）」β)之含有比例以丙烯酸換算為18重量％以上， 較佳為60重量％以下。又，前述含有比例較佳為2〇重 量/〇以上，特佳為20至60重量。該比例為丨8重量％ 以下時’在第4步驟中則不能進行2相分離。 使溶液中的丙烯酸（鹽）之含有比例以丙烯酸換算為 1 8重量〇/0以上之方法方面，舉出為調整於第2步驟所使 用的丙烯酸水溶液之濃度及鹼水溶液的使用量之方法 等。又’若液體中的丙烯酸（鹽）之含有比例為1 8重量％ 以下時，蒸餾除去水，或追加丙烯酸（鹽），亦可使丙烯 酸（鹽）的含有比例成為前述比例。 尚且’溶液中的丙烯酸（鹽）之比例，係可由液相層 析法、氣相層析法及離子色層分析法等的方法測定。在 -16- 201223939 該情況下’預先使用丙烯酸（鹽）以製作檢量線’可藉由 絕對檢量線法校正所測定之値以決定比例。當測定為丙 稀酸鹽時，藉由計算以換算成丙烯酸。 再者’在專利文獻1(特開2006-213647號公報）中’ 6己載於實施例的水相中之丙烯酸濃度為1 6.6重量。/❶’在 專利文獻2 (特開昭6 1 - 2 4 3 0 4 6號公報）中，記載於實施例 3的水相中之丙烯酸濃度為ι5 $重量％，均非2相分離 者0 本發明者等，發現以前述熟知文獻中完全未揭示之 使溶液中的丙烯酸（鹽）濃度為特定値，可達成前述熟知 文獻中亦完全未揭示建議之可達成後述第4步驟中的2 相分離。 4 .第4步驟 第4步驟係將第3步驟中所獲得之液體分離成大多 包含丙缚酸（鹽）之相（上層）、與大多包含硫酸鹼金屬鹽之 相（下層）之2相之步驟。 該情況下的溫度方面，較佳 。 敉佳為25至40°C，更佳為 3 〇至4 0 C。藉由維持於贫许$阁 出。 '皿度範圍，可防止硫酸鹽的析 層二成大多包含丙稀酸(鹽)之相(上 層）、、大多包含硫酸驗金屬鹽之 方面’雖無特別之限制，但0之2相之方法 舉出為m Φ v 权佳為利用比重差之方法， 舉出為進仃靜置分離之方法 當進行靜置分離時，可在前广分離之方法等。 第3步驟所獲得之液體一定時間。 置 201223939 5. ·第5步驟 步驟所獲得之液體的大多包 ’回收殘留的大多包含丙烯 第5步驟係分館於第43 含硫酸驗金屬鹽之相（下層）， 酸（鹽）之相（上層）之步驟。 藉由第4步驟，厶M . a ^ t & μ…、The ratio of the content of the metal salt to acrylic acid is 篡A 佚 1 1 1 1 1 1 ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; a step of a salt phase (upper layer) and a phase of a phase (lower layer) containing a large amount of an alkali metal sulfate; the majority of the liquids of the liquid mostly contain a fifth step: fractionation in the fourth step, the sulfur obtained in the step The step of recovering the phase of the metal salt (lower layer), recovering the phase of the residual acid and/or its alkali metal salt (upper layer). -6 - 201223939 [The fruit of the invention] According to the invention, it is not required to use an organic solvent The acrylic acid extraction step 'is a method for producing acrylic acid which can easily recover acrylic acid by a simple method of removing the lower liquid which has been separated by two phases, and which can make the concentration of acrylic acid in the recovered liquid high, and has excellent recovery efficiency, and acrylic acid The method of recovering the same. The acrylic acid recovered can be directly or refined, and then used in the production of an acrylate or a polymer. [Embodiment] [Formation for carrying out the invention The present invention is described in detail below. The present invention relates to a method for producing an acrylate characterized by sequentially performing the following first steps to the fifth step. Step 1: stirring and mixing acrylic acid in the presence of an acid catalyst An alcohol, a step of obtaining an acrylate-containing reaction liquid which has been subjected to an esterification reaction; 'Step 2: adding an aqueous alkali solution to the reaction liquid obtained in the second step to neutralize, and separating into an organic phase and an aqueous phase. a step of fractionating the organic phase to recover the propionate; a third step: fractionating the aqueous phase obtained in the second step, adding a sulfuric acid aqueous solution having a sulfuric acid concentration of 70% by weight or more, and adjusting the pH to below 4.0. The liquid acrylic acid and/or its alkali metal salt: a step of containing 18% by weight or more in terms of acrylic acid; the fourth step: separating the liquid obtained in the third step into a large eve containing acrylic acid and/or its base Step of the phase of the metal salt (upper layer) and the phase of the majority of the package = the phase of the acid salt (lower layer); 201223939 Step 5: fractionation of the liquid obtained in the fourth step The phase of the alkali metal sulfate (lower layer)' is a step of recovering a majority of the phase (upper layer) of the acrylic acid and/or its alkali metal salt. Further, the present invention relates to the following steps 3, steps to Step 5 is a method for recovering acrylic acid. Step 3: Preparing an acrylic acid and/or an alkali metal salt thereof, an alkali metal sulfate, and water, having a pH of 4.0 or less, and an acrylic acid and/or a metal salt thereof a step of containing a liquid in a ratio of 18% by weight or more in terms of acrylic acid; Step 4: The liquid obtained by separating the step 3' is a phase mostly containing acrylic acid and/or an alkali metal salt thereof (upper layer), a step of phase 2 with a phase (lower layer) containing mostly an alkali metal sulfate; step 5': fractionating a phase of the liquid obtained by the step 4', which mostly contains an alkali metal sulfate (lower layer), and recovers most of the residue. A step comprising a phase (upper layer) of acrylic acid and/or a metal salt thereof. (Method for Producing Acrylate) According to the method for producing an acrylate of the present invention, various acrylates can be produced, which are preferably suitable for the production of high-boiling acrylates, and particularly preferably at a pressure of 13.3 kPa. Manufacture of acrylate having a boiling point of 100 ° C or higher. The boiling point at a pressure of 13.3 kPa is 1 Torr. (The above acrylate aspect is exemplified by an acrylate of a phenol alkylene oxide adduct, an acrylate of a nonylphenol alkylene oxide adduct, and an acrylate specific phenol for an @香phenol phenol alkylene oxide adduct. Acrylates of cyclodextrose-like addition compounds; acrylates of 2-ethylhexanol alkylene oxide adducts; • 8 - 201223939 tricyclic fluorene dihydroxy hydrazide acrylates and other polycyclic alkyl acrylates a polycyclic alkyl diacrylate such as tricyclopentane diacetate; a mono or diacrylate of ethylene glycol; a mono or diacrylate of propylene glycol; a mono or diacrylate of pentanediol; One or two acrylates of an alkene diol such as an alcohol or a diacrylate; one or two acrylates of diethylene glycol, one or a diene ester of triethylene glycol, or one of tetraethylene glycol One of a polyhydrocarbyl glycol such as a diacrylate, a diacrylate of polyethylene glycol, a mono- or diacrylate of dipropylene glycol, a mono- or diacrylate of tripropylene glycol or a mono- or diacrylate of polypropylene glycol or diacrylic acid Ester; di or triacrylate of glycerol and di- or tri-propane of diglycerol a di or triacrylate of a glycerol such as an acid ester; a di- or triacrylate of a cycloalkane adduct of a glycerol; a mono- or di-acrylate of a bisphenol A alkylene oxide adduct and a bisphenol F Oxygen-fired adducts of mono- or di-acrylic acid I, etc., of di-epoxy epoxy adduct mono- or di-acrylate; trimethylolpropane triacrylate, ditrihydroxypropane propane tripropionate, two Polyols such as trimethylolpropane tetraacrylate, neopentyl alcohol tripropylene ester, neopentyl alcohol tetraacrylate, dipentaerythritol penta (decyl) acrylate, and dipentaerythritol hexaacrylate Polyacrylate; poly(indenyl) acrylate of alkylene oxide adduct of the polyalcohol; di- or tri(indenyl) acrylate of isodecane cyanide adduct adduct; Or acid such as diene oxide ring olefin acid-9 - 201223939 and polyester acrylate, etc. The epoxy burning in epoxy compound addition is exemplified by epoxy bromide and propylene oxide. The number of additions of the alkylene oxide is preferably from 丨 to 2 〇. Among the acrylates, it can be prevented in the i-th step described later. From the viewpoint of dissolving the acrylate on the phase side, it is more suitable for a method for producing a hydrophobic acrylate than a hydrophilic acrylate such as a mono- or diacrylate of an olefin-based diol. Step to Step 5. 1. Step 1 In the first step, in the presence of an acid catalyst, the acrylic acid and the alcohol are mixed and mixed to obtain an acrylate-containing reaction liquid which has been subjected to an esterification reaction. On the other hand, according to a usual method, for example, a method of heating and stirring an acrylic acid and a high-boiling alcohol in the presence of an acid catalyst in an organic solvent, etc., an alcohol may be used corresponding to the aforementioned acrylate. An alkylene oxide adduct of a phenolic alkylene oxide adduct, a nonylphenol-based alkylene oxide adduct, and an anisidine-based alkylene oxide adduct; 2-ethylhexanol An alkylene oxide adduct; a polycyclic alkyl alcohol such as tricyclic quinone dihydroxymethyl; a polycyclic alkyl diol such as tricyclic quinone dihydroxymethyl; ethylene glycol, propylene glycol, pentanediol and Olefinic diols such as hexanediol; monoethyl alcohol, triethylene glycol, tetraethylene Polyolefin-based diols such as polyethylene glycol, dipropylene glycol, tripropylene glycol, and polypropylene glycol; -10* 201223939 glycerols such as glycerol and diglycerin; propylene oxides of glycerol a double-anti-epoxyalkylene adduct of a bisphenol A alkylene oxide adduct and a bisphenol F alkylene oxide adduct; monomethylolpropane, ditrimethylolpropane triacrylate, Polyalcohols such as pentaerythritol triacrylate and dipentaerythritol; alkylene oxide adducts of such polyalcohols; isodecane cyanide adducts; and polyacetates. The alkylene oxide in the alkylene oxide adduct is exemplified by ethylene oxide and propylene oxide. Further, the number of additions of the alkylene oxide is preferably from 1 to 2 Å. Among these alcohols, as described above, it is preferred to make the obtained acrylate into a hydrophobic alcohol. The proportion of the acrylic acid to be used may be appropriately set in accordance with the objective acrylate, and is preferably from 1 Torr to 2.0 mols, more preferably from 1 Torr to 1.5 mols, based on the total of the hydroxyl groups of the 1-mole high-boiling alcohol. The acid catalyst is exemplified by an inorganic acid such as sulfuric acid or the like, and a continuous acid such as a benzoic acid, a methic acid or a trifluoromethylene. The ratio of the use ratio of the acid catalyst is preferably from 0.1 to 10% by weight based on the weight of the reaction liquid containing the organic solvent. The esterification reaction system can be carried out in accordance with a usual method. The reaction temperature is appropriately set depending on the raw materials and the purpose to be used. From the viewpoint of shortening the reaction time and preventing polymerization, it is preferably 65 to 140 ° C', more preferably 75 to 120 ° C. By setting the reaction temperature to 65 〇c or more, the esterification reaction can be rapidly carried out and the yield can be prevented from being lowered, and the reaction temperature can be further lowered to 140. (: The following 'prevents the thermal polymerization of acrylic acid or the resulting acrylate. 201223939 The pressure of the reaction is to prevent acrylic acid or acrylic acid generated::: As described later, it is preferably carried out under reduced pressure. For the purpose of thermal polymerization, it is preferred to azeotrope with an organic solvent while promoting dehydration during the brewing reaction. The resulting water is preferably an aromatic hydrocarbon in terms of an organic solvent; hexane and heptane. Etc.: alicyclic hydrocarbons such as dimethyl benzene, etc., and the amount of organic solvent such as cyclohexane and cyclohexane, the relative amount is preferably A; It is a ratio of 10 to 75% by weight of S-leaf to 55% by weight. More preferably, it is a 15 s oxidation reaction system for the purpose of preventing acrylic acid or polymerization, preferably at 75 Å. The enthalpy is preferably carried out at 75 to 12 Torr. It is preferred to carry out the esterification reaction in the presence of oxygen in order to prevent the presence of sputum. For the same purpose, it is preferred to add a polymerization inhibitor to the reaction. In the case of polymerization inhibitors, for example, there are ~ liquid Pingzhuo Fengbaiji compound and metal salt, etc. For organic compounds, examples of helmet-poor ones are 醌, hydroquinone, o-diphenol, = grade; 醌, 氲醌-methyl ether, naphthoquinone, grade III Ding ou diphenol, phenol, monodecyl tertiary butyl phenol, tertiary butyl phenol, dioxin hydroxy phenanthrene and phen 〇 thiazine. In terms of human metal salt, it is liquefied copper. And a metal copper compound such as copper sulfate or the like, a metal iron compound such as ferrous sulfate, etc. The amount of the polymerization inhibitor added is preferably from 10 to 50,000 ppm, more preferably 1 Torr, depending on the amount of acrylic acid used as the raw material. When it is 100 ppm or more, the polymerization prevention effect can be fully exerted. When -12-201223939 is 10,000 ppm or less, coloring can be prevented on the one hand, and the hardenability of the product can be prevented from being lowered on the one hand. The progress of the reaction is to monitor the amount of water generated by the esterification reaction, that is, the amount of dehydration. On the one hand, the concentration of the acid component in the reaction solution is analyzed, and the composition of the produced acrylic acid vinegar is analyzed to determine the composition of the product. And 'the reaction in the presence of the aforementioned oxygen Specifically, it is a method of performing anti-friction in an oxygen-containing gas atmosphere on the one hand, and introducing an oxygen-containing gas into a reaction liquid while performing a reaction on the one hand. A typical oxygen-containing gas j is two gases, but industrially. Considering the danger of flash explosion, it is suitable to use a gas with an oxygen content of less than 3 5% by volume. The oxygen-containing system can be prepared by mixing air with an inert gas. For inert gas, nitrogen or argon is usually used. 2. Step 2 Step 2 After adding the alkali water solution to the towel*, the material is separated from the organic 4 towel to obtain the reverse phase of the step of recovering the acrylic vinegar. The organic phase of the phase and the aqueous phase is added to the third aqueous solution by the aqueous solution. The reaction liquid obtained from the reaction step is an acid component. Knife • Removal of acrylic acid and acid catalysts, etc., for use in neutralized alkaline water, nitrogen, nitrogen oxides, potassium oxychloride, etc., for the determination of metal salts, oxynitride oxides, and sodium carbonate. , test the metal oxides of the metal oxides, etc. It is preferred from the viewpoint that the alkali in the aqueous alkali solution has an effect of eight. It is preferable that the amount of the molar knife is such that the acidity with respect to the reaction liquid is in the above range, and it is more preferable that it is the neutralization of the long-term component. Further, the concentration of the aqueous solution is preferably from i to 25% by weight, more preferably from 3 to 25% by weight, particularly preferably from 10 to 25% by weight. By setting the concentration to 1% by weight or more, it is possible to prevent an increase in the amount of water discharged after the neutralization treatment; and when it is 25 parts by weight or less, the polymerization of the acrylate can be prevented. The neutralization treatment of the second step is to supply the reaction solution and the aqueous solution to the tank device and stir to carry out the treatment, or to use a static mixer or the like for treatment. Further, an organic solvent may be added to the reaction liquid before the neutralization for the purpose of adjusting the specific gravity or the like. In the second step, the reaction liquid obtained by adding the aqueous alkali solution to the second step is neutralized and separated into two phases of an organic phase and an aqueous phase. It can also be divided into several times to apply the neutralization process. _Pre-treatment In the implementation and before the treatment, the washing process. When the polymerization inhibitor of the reaction liquid can be used for various purposes, it is particularly preferable to use a copper system in the esterification reaction to efficiently remove the copper-based polymerization inhibitor. Specifically, a method of mixing and washing the water may be carried out by mixing water in the reaction liquid obtained by the acetalization reaction according to a usual method. In terms of water, it is preferred to use pure water. • Acrylate final product. In the second step, after the neutralization treatment, the organic phase and the aqueous phase are separated into two phases to separate the organic phase, and the acrylic acid is recovered. The method of separation of the organic phase can extract the lower aqueous phase. The extracted aqueous phase is subjected to the third step described later. 201223939 The above organic layer after fractionating the aqueous phase, if necessary, can remove the organic solvent to become the acrylic acid of the final product. The solvent removal treatment can be carried out in accordance with a usual method, and is, for example, a method of depressurizing a solvent to remove an organic solvent. The degree of vacuum of the solvent removal tank can be appropriately set depending on the raw materials and purpose to be used, and it is preferable to gradually increase the pressure with respect to the degree of removal of the solvent from 22 to 50 kPa'. The desolvent treatment is preferably to supply oxygen in order to suppress thermal polymerization of the acrylate, and to add a polymerization inhibitor, for example, to the above. . . Hereinafter, it is carried out under reduced pressure. If necessary, the organic solvent may be removed from the organic phase in the solvent removal tank in the solvent removal treatment, and the filter aid may be supplied to the solvent removal tank in the g-type horizontal filter plate filter connected to the solvent removal tank. A filter aid is deposited to carry out a filtration treatment of the reaction product. Further, the organic layer may be subjected to a water washing treatment before the solvent removal treatment as necessary. 3. The third step and the third step are the aqueous phase obtained by the second step in the second step (hereinafter referred to as the aqueous phase (7).) 'The sulfuric acid aqueous solution having a sulfuric acid concentration of 7 〇 wt% or more is added thereto, and the pH is adjusted to 4. In the following, the content ratio of the acrylic acid and/or the metal salt thereof in the liquid is 18% by weight or more in terms of acrylic acid. 〇 'The sulfuric acid concentration of the aqueous sulfuric acid solution used in the third step is the weight. When the upper right side is less than 70% by weight, the two-phase separation in the fourth step becomes difficult. The recovery rate of propionic acid (salt) is lowered. The 201223939 aqueous sulfuric acid solution is preferably a concentration of 1 〇 〇 heavy sulfuric acid, preferably 75% by weight or more and more preferably 99% by weight. the following. In the third step, an aqueous solution of sulfuric acid is added to the aqueous phase to be 4.0 or less. If the pH is more than 4, ^ ^ ^ ^ ^ ^ ^, the two-phase separation of the four steps of the turf is difficult, and the recovery of acrylic acid (salt) is lowered. The pH of the preferred aqueous phase is in the range of from 0 to 4.0, more preferably in the range of U 35 . The amount of the aqueous sulfuric acid solution to be added to the aqueous phase (2) is any amount such that the pH of the aqueous phase is 4 Torr or less. The temperature at which the aqueous sulfuric acid solution is added to the aqueous phase (2) is preferably 25 Å. More preferably, it is 25 to 4 (TC' is particularly preferably 3 to 4 Torr. By setting the temperature to 25t: or more, the precipitation of the sulfate 3 can be prevented in the third step. In the method of producing an ester, in the third step, the content ratio of acrylic acid and/or an alkali metal salt thereof (hereinafter referred to as "acrylic acid (salt)" β) in the liquid is 18% by weight or more in terms of acrylic acid, Further, the content ratio is preferably 2% by weight or more, particularly preferably 20 to 60% by weight. When the ratio is 8% by weight or less, '2 phases cannot be performed in the fourth step. The method of adjusting the content of the acrylic acid (salt) in the solution to 18 wt%/0 or more in terms of acrylic acid is to adjust the concentration of the aqueous acrylic acid solution used in the second step and the amount of the aqueous alkali solution used. In the case where the content of the acrylic acid (salt) in the liquid is 18% by weight or less, the water is distilled off, or acrylic acid (salt) is added, and the content ratio of the acrylic acid (salt) may be set to the above ratio. 'Acrylic acid in solution The ratio of salt) can be determined by liquid chromatography, gas chromatography, ion chromatography, etc. In the case of -16-201223939, 'pre-use acrylic acid (salt) to make a calibration curve' The enthalpy of the measurement can be corrected by the absolute calibration method to determine the ratio. When it is determined to be an acrylate, it is calculated to be converted into acrylic acid. Further, the patent document 1 (Japanese Laid-Open Patent Publication No. 2006-213647) The concentration of the acrylic acid in the aqueous phase of the example of the present invention is 1 6.6. The weight of the acrylic acid in the aqueous phase of the embodiment is described in Example 3 of the Patent Document 2 (Japanese Laid-Open Patent Publication No. Hei. No. Hei. No. Hei. The concentration of acrylic acid in the aqueous phase is ι 5 $% by weight, and both of them are not two-phase separators. The present inventors have found that it is possible to achieve a specific concentration of acrylic acid (salt) in the solution, which is not disclosed in the aforementioned well-known literature. The above-mentioned well-known literature also does not disclose at all that the two-phase separation in the fourth step described later can be achieved. 4. The fourth step, the fourth step, separates the liquid obtained in the third step into mostly containing acrylic acid (salt). The phase (upper layer), and mostly contains alkali metal sulfate The step of the phase of the phase (lower layer). The temperature in this case is preferably. The temperature is preferably from 25 to 40 ° C, more preferably from 3 to 40 ° C. By maintaining the leanness. The range of the degree of the sulphate can prevent the precipitation of the sulphate from being mostly composed of the phase of the acrylic acid (salt) (the upper layer), and most of the aspects including the metal salt of the sulphuric acid test, although there is no particular limitation, but the method of the phase 2 The method of m Φ v is preferably a method of utilizing a difference in specific gravity, and a method of separating and separating the mixture is carried out, and when it is subjected to static separation, the method can be widely separated before, etc. The liquid obtained in the third step is fixed for a certain period of time. Set 201223939 5. · Most of the liquids obtained in the fifth step of the process's recovery of the majority of the residual propylene containing the fifth step of the branch in the 43rd phase of the metal salt containing the test salt (lower layer), the acid (salt) phase ( The steps of the upper layer). By the fourth step, 厶M . a ^ t & μ...,
(鹽）之相。 所回收之相中的丙烯酸（鹽）的比例係隨所使用的原 料或條件而異，較佳為獲得包含25至6〇重量％的丙烯 酸（鹽）之水溶液。 •丙烯酸（鹽）之再利用 所回收之丙烯酸（鹽）水溶液雖隨處理條件而變動， 但獲得以丙烯酸為主成分，包含少許丙稀酸的驗金屬鹽 之水溶液。亦可直接使用所回收之丙烯酸（鹽）水溶液， 又亦可進行精製後使用，再者亦可分離丙烯酸後使用。 所回收之丙烯酸（鹽）水溶液係隨做為目的的用途， 未精製而藉由直接進行聚合，而可適當地使用於聚丙烯 酸或聚丙烯酸鹽的製造。 所獲得的聚丙烯酸或聚丙稀酸鹽（較佳為鈉鹽）係可 較佳地使用於分散劑、增黏劑及凝結劑等的用途。 再者，當要求純度之用途時’在前述聚合之前進行 丙烯酸（鹽）水溶液之精製’可使用精製後之丙烯酸（鹽） 201223939 當從所回收之丙烯酸（鹽）水、、容 時，舉出為添加甲苯等的有機溶劑夜分離丙烯酸後使用 水溶液，進行加熱以共沸蒸餘除=所回收之丙彿酸（鹽） 所獲得的丙烯酸係可使用做 1方法。 製造原料。又，亦可使用做為第一 物及丙賴的 •下層之廢棄·處s 步驟中的原料丙烯酸。The phase of (salt). The proportion of the acrylic acid (salt) in the recovered phase varies depending on the raw materials or conditions used, and it is preferred to obtain an aqueous solution containing 25 to 6 % by weight of acrylic acid (salt). • Recycling of acrylic acid (salt) The recovered aqueous solution of acrylic acid (salt) varies depending on the processing conditions, but an aqueous solution containing a metal hydroxide containing a small amount of acrylic acid as a main component of acrylic acid is obtained. The recovered aqueous solution of acrylic acid (salt) may be used as it is, or may be used after purification, or it may be used after separating acrylic acid. The recovered aqueous solution of the acrylic acid (salt) is used for the purpose of the purpose, and can be suitably used for the production of polyacrylic acid or polyacrylic acid salt by directly performing polymerization without purification. The obtained polyacrylic acid or polyacrylic acid salt (preferably sodium salt) can be preferably used for a dispersant, a tackifier, a coagulant or the like. Further, when the use of purity is required, 'the purification of the aqueous solution of the acrylic acid (salt) before the polymerization is carried out' can be carried out using the purified acrylic acid (salt) 201223939 when the recovered acrylic acid (salt) water is used. In order to add an aqueous solution of toluene or the like to an organic solvent, an aqueous solution is used, and heating is carried out to carry out azeotropic distillation to remove the recovered acrylic acid (salt). Manufacturing raw materials. Further, it is also possible to use the raw material acrylic acid in the step of the disposal of the lower layer of the first layer and the second layer.
從處理槽抽取之大多包A 3瓜酉夂驗金屬鹽之相做為下 層的處理方法方面並無㈣之限制，可直接進行燃燒處 理 亦可冷卻該/谷液，分離硫酸鹼金屬鹽成為結晶。 又’蒸顧除去水後’藉由分離所析出的硫酸鹽，亦 可回收做為丙烯酸（鹽）水溶液。 (丙烯酸之回收方法） 本發明的丙烯酸之回收方法係關於以依次實施下述 第3’步驟至第5’步驟為特徵。 第3’步驟：調製含有丙烯酸及/或其驗金屬鹽、硫酸 鹼金屬鹽、以及水，pH為4.0以下，而且丙浠酸及/或其 驗金屬鹽的含有比例以丙稀酸換算為1 8重量％以上之液 體之步驟； 第4’步驟：分離於第3’步驟所獲得之液體成為大多 包含丙烯酸及/或其鹼金屬鹽之相（上層）、與大多包含硫 酸鹼金屬鹽之相（下層）之2相之步驟； 第5’步驟：分餾於第4’步驟所獲得的液體之大多包 含硫酸鹼金屬鹽之相（下層），回收所殘留之大多包含丙 烯酸及/或其鹼金屬鹽之相（上層）之步驟。 -19- 201223939 6.第3’步驟 第3,步驟係調製含有丙烯酸及/或其鹼金屬鹽、硫酸 鹼金屬鹽' 以及水，pH為4·0以下’而且丙烯酸及/或其 鹼金屬鹽的含有比例以丙烯酸換算為1 8重量％以上之液 體之步驟。 於第3’步驟所獲得的液體之pH為4.〇以下之範圍， 較佳為0至4.0之範圍，更佳為1至3.5之範圍《當pH 為超過4.0時，第4步驟的2相分離變困難，丙烯酸（鹽） 的回收率降低。 於第3’步驟所獲得的液體中之丙烯酸及/或其鹼金 屬鹽的含有比例以丙烯酸換算為1 8重量。/〇以上，較佳為 60重量％以下。又，前述含有比例較佳為2〇重量％以上， 特佳為20至60重量％。前述含有比例為18重量％以下 時’在第4 ’步驟卡則不能進行2相分離。 於第3’步驟所獲得的液體中’丙稀酸的驗金屬鹽及 硫酸驗金屬鹽之鹼金屬鹽方面，雖無特別之制限，較佳 舉出為納鹽、及鉀鹽，更佳為舉出為鈉鹽。 又於第3步驟所獲得之液體，較佳為經過前述本 發明的丙缔酸酯夕制、土 士、+ & 製知方法中的第1步驟至第3步驟所 獲得之液體。 再者，第3’步驟中的液體之溫度方面，較佳為25。〇 以上’更佳為25至4(rc ’特佳為3〇至4〇。〇。藉由使液 體的溫度為25°Γ tv I*，ότ λ* L U上’可在第3,步驟防止硫酸鹽析出。 -20- 201223939 7.第4’步驟 第4’步驟係分離於第3,步驟所獲得之液體成 包含丙浠酸及/或其鹼金屬鹽之相（上層）、與大多 硫There is no (4) limitation on the treatment method of the bottom layer of the metal salt which is extracted from the treatment tank as the lower layer. The combustion treatment can be directly carried out to cool the /coline liquid, and the alkali metal sulfate is separated into crystals. . Further, after the steam is removed, the precipitated sulfate can be recovered as an aqueous solution of acrylic acid (salt) by separating the precipitated sulfate. (Recovery Method of Acrylic Acid) The method for recovering acrylic acid of the present invention is characterized by sequentially performing the following steps 3' to 5'. Step 3': preparing the acrylic acid and/or the metal salt thereof, the alkali metal sulfate, and water, the pH is 4.0 or less, and the content ratio of the propionic acid and/or the metal salt thereof is 1 in terms of acrylic acid. Step of 8% by weight or more of liquid; Step 4': The liquid obtained by the step 3' is separated into a phase containing a large amount of acrylic acid and/or an alkali metal salt thereof (upper layer), and a phase mostly containing an alkali metal sulfate Step of the two phases (lower layer); Step 5': fractionation of the liquid obtained in the step 4', which mostly contains the alkali metal sulfate phase (lower layer), and the recovered residual mostly contains acrylic acid and/or its alkali metal The step of the salt phase (upper layer). -19- 201223939 6. Step 3 'Step 3, the step is to prepare acrylic acid and/or its alkali metal salt, alkali metal sulfate 'and water, pH below 4·0' and acrylic acid and/or its alkali metal salt The step of containing a liquid in an amount of 18% by weight or more in terms of acrylic acid. The pH of the liquid obtained in the 3' step is in the range of 4. 〇 below, preferably in the range of 0 to 4.0, more preferably in the range of 1 to 3.5. When the pH is more than 4.0, the 2nd phase of the 4th step The separation becomes difficult and the recovery of acrylic acid (salt) is lowered. The content ratio of the acrylic acid and/or its alkali metal salt in the liquid obtained in the third step is 18 parts by weight in terms of acrylic acid. Above /, 较佳 is preferably 60% by weight or less. Further, the content ratio is preferably 2% by weight or more, particularly preferably 20 to 60% by weight. When the content ratio is 18% by weight or less, the two-phase separation cannot be performed in the fourth step card. In the liquid obtained in the third step, the metal salt of the acrylic acid and the alkali metal salt of the metal salt of the sulfuric acid salt are not particularly limited, and are preferably a sodium salt or a potassium salt, more preferably Give it as a sodium salt. Further, the liquid obtained in the third step is preferably a liquid obtained by the first step to the third step in the method for producing the propionate, the toast, and the + & Further, the temperature of the liquid in the third step is preferably 25 in terms of the temperature. 〇 Above 'better is 25 to 4 (rc 'extra good is 3〇 to 4〇. 〇. By making the liquid temperature 25°Γ tv I*, ότ λ* LU on 'can be in the third step, prevent Sulfate precipitation. -20- 201223939 7. Step 4' Step 4' is separated from the third step, the liquid obtained in the step is a phase containing a propionic acid and/or its alkali metal salt (upper layer), and a large sulfur
酸鹼金屬鹽之相（下層）之2相之步驟。 5 M 第4 ’步驟係除了使用於第3， ^ ^ ^ i®. ^ ^ 7诹所獲付之液體取代 於第3步驟所獲侍之液體以外，盥 丹弟4步驟相同，鮫佳 之樣態亦相同。 $ 8.第5’步驟 第5,步驟係分館於第4,步驟所獲得之液體的大多包 含硫酸鹼金屬鹽之相(下層），自收所殘留之大多包含丙 烯酸及/或其鹼金屬鹽之相（上層）之步驟。 第5步驟係除了使用於第4,步驟所獲得之液體取代 於第4步驟所獲得之液體以外，與第5步驟相同，較佳 之樣態亦相同。 藉由本發明的丙烯酸之回收方法所回收之丙燦酸 (鹽)水溶液係隨處理條件而變動，獲得以丙烯酸為主成 分’包含少許丙稀酸的驗金屬鹽之水溶液。亦可直接使 用所回收之丙烯酸（鹽）水溶液，又亦可進行精製後使 用，再者亦可分離丙烯酸後使用。 又亦可藉由熟知的方法，從藉由本發明的丙烯酸 之回收方法所回收之丙烯酸（鹽）水溶液，分離及/或精製 丙烯酸及/或其鹼金屬鹽。 又如在前述丙烯酸（鹽）之再利用所述，所回收之 丙烯酸(鹽)水溶液係隨做為目的之用途，可藉由未精製 而直接進行聚合，較佳地使用於聚丙烯酸或聚炳烯酸鹽 的製造。 201223939 [實施例] 以下，舉出實施例及比較例，較具體地說明本發明。 再者，以下「％」表示重量％的意思。 (實施例1) 在10L的反應器中置入3,0〇〇g的丙烯酸、l，47〇g的 二新戊四醇（以下稱為「〇?£1'」。）、7〇莒的78%之硫酸、 10g的氫醌（以下稱為「HQ」。）及2,450g的甲苯’在53kPa 的壓力下、設定於1001的油浴中加熱’以縮合水做為 與甲苯的共沸水而除去，同時反應1 0小時。此時的反應 液重量為6,250g。 在反應結束後，追加3,500g的甲苯。接著，在添加 325g的純水並攪拌後靜置，分離成上層（有機相）與下層 (水相）。從反應器抽取下層（水相），回收上層（有機相）。 在該上層（有機相）中，加入l，7〇〇g的2〇%之氫氧化 鈉水溶液並攪拌後靜置，獲得9,000g的上層（有機相）與 2,400g的下層（水相）。 從反應器抽取該下層（水相）（以下稱為「中和廢 水」。）。又，該中和廢水係在以下所示之實施例2及3、 以及比較例1中被使用。The step of the two phases of the phase of the acid-base metal salt (lower layer). 5 M The 4th step is the same as the liquid obtained in the third step except for the liquid obtained in the third, ^ ^ ^ i®. ^ ^ 7诹. The state is also the same. $ 8. Step 5', step 5, the steps are in the fourth step, the liquid obtained in the step mostly contains the alkali metal sulfate phase (lower layer), and most of the residual material contains acrylic acid and/or its alkali metal salt. The step of the phase (upper layer). The fifth step is the same as the fifth step except that the liquid obtained in the step is replaced by the liquid obtained in the fourth step, and the preferred embodiment is also the same. The aqueous solution of the acrylic acid (salt) recovered by the method for recovering acrylic acid of the present invention is changed depending on the treatment conditions, and an aqueous solution containing a metal hydroxide component containing a small amount of acrylic acid is obtained. Alternatively, the recovered aqueous solution of acrylic acid (salt) may be used as it is, or it may be used after purification, or it may be used after separating acrylic acid. Further, acrylic acid and/or an alkali metal salt thereof may be isolated and/or purified by an aqueous solution of acrylic acid (salt) recovered by the acrylic acid recovery method of the present invention by a well-known method. Further, as described in the reuse of the above-mentioned acrylic acid (salt), the recovered aqueous solution of the acrylic acid (salt) is used for the purpose of the purpose, and can be directly polymerized by unrefining, preferably used in polyacrylic acid or polyacrylic acid. Manufacture of enoates. 201223939 [Examples] Hereinafter, the present invention will be specifically described by way of examples and comparative examples. In addition, the following "%" means the weight %. (Example 1) 3,0 g of acrylic acid and 1,47 g of dipentaerythritol (hereinafter referred to as "〇?£1'") were placed in a 10 L reactor. 78% of sulfuric acid, 10 g of hydroquinone (hereinafter referred to as "HQ".) and 2,450 g of toluene 'heated in an oil bath set at 100 kPa under a pressure of 53 kPa. 'Condensed water as azeotropic water with toluene While removing, the reaction was carried out for 10 hours at the same time. The weight of the reaction solution at this time was 6,250 g. After the reaction was completed, 3,500 g of toluene was added. Next, 325 g of pure water was added and stirred, and then allowed to stand, and separated into an upper layer (organic phase) and a lower layer (aqueous phase). The lower layer (aqueous phase) was taken from the reactor and the upper layer (organic phase) was recovered. Into the upper layer (organic phase), a 2% by weight aqueous solution of 2% by weight of sodium hydroxide was added thereto, and the mixture was stirred and allowed to stand to obtain 9,000 g of an upper layer (organic phase) and 2,400 g of a lower layer (aqueous phase). The lower layer (aqueous phase) is extracted from the reactor (hereinafter referred to as "neutralized waste water"). Further, the neutralized wastewater was used in Examples 2 and 3 and Comparative Example 1 shown below.
使用液相層析儀[島津製作所（股）製，製品名為 LC-10A]，以絕對檢量線法分析所獲得的中和廢水時，含 有32.2%的丙烯酸鈉（相當於24 7〇/〇的丙烯酸）。 S 再者，針對上層（有機相），進一步加入l，360g的2〇% 之氫氧化納水溶液並搜拌後靜置，分離成上層（有機相° 與下層（水相）。在該上層（有機相）_ ,在加入4〇〇g的純 -22- 201223939 水並攪拌後靜置，分離成8,660g的上層（有機相）與下層 (水相）》添加1.3g的氫醌一甲基醚（以下稱為「mq」）於 所獲得的上層（有機相）中，在減壓下蒸餾除去甲笨，獲 得2,750g的丙烯酸酯（二新戊四醇五丙烯酸酯與六丙 酸酯的混合物）。 在300g的上述中所獲得之中 π >甲，硬硬加入 98%之硫酸直到變成ρΗ成為3。所添加#咖之硫酸為 46.9g。又’維持硫酸添加時的液體之溫度於25至30。(：。 接著，將液溫保溫於30至35t並靜置，分離成上 層（丙烯酸水溶液層）與下層（硫酸鈉水溶液層）。 將分離成2相的液體移至分液漏斗中，抽取下層（硫 酸鈉水溶液層）。 μ 所獲得的上層之丙烯酸水溶液層為M65g，丙烯酸 濃度為4G.6%，相對於包含於中和廢水的丙稀酸，可回 收80.4%的丙稀酸。 再者，針對下層的硫酸鈉水溶液，冷卻直到約丨， 固液分離所析出的結晶之結果為獲得i22 ig的含有 37.7%硫酸納之結晶與63 2§的含有135%丙稀酸、57% 硫酸納之水溶液。 (實施例2) 在3 〇 〇 g的於實施例 78%之硫酸直到pH變成3。再者，維持硫酸添加日⑷ 皿度於25至30。(：。又，所添加的78%之硫酸』 5 9.0g 〇 册狹溫保溫於3 〇至 使者 層（丙烯酸水溶液層）與下層（硫酸鈉水溶液層） -23- 201223939 將分離成2相之溶液移至分液漏斗中，抽取下層（倚 酸鈉水溶液層）。 所獲得的上層之丙烯酸水溶液層為151.8g，丙烯峻 濃度為37.4% ’相對於包含於中和廢水的丙烯酸，可回 收76.7%的丙烯酸。 (實施例3) 在300g的於實施例1所獲得之中和廢水中緩緩加入 9 8 %之硫酸直到p Η變成2。再者’維持硫酸添加時的液 體之溫度於25至30 °C。又，所添加的98%之硫酸為 52.1g 〇 接著’將液溫保溫於30至35。(：並靜置，分離成上 層（丙烯酸水溶液層）與下層（硫酸鈉水溶液層）。 將分離成2相之溶液移至分液漏斗中，抽取下層（硫 酸鈉水溶液層）》 所獲得的上層之丙烯酸水溶液層為m 4g，丙烯酸 濃度為44.6%，相對於包含於中和廢水的丙稀酸，可回 收7 7.4 %的丙烯酸。 (比較例1) 在3〇〇g的於實施例1所獲得之中和廢水中緩緩加 98%之硫酸直到pH變成4.2。再者，維持硫酸添加時 液體之溫度於25至3(KC。又，所添加的98%之硫酸 32g 〇 3 5 °C，但因未分離成2 接著’雖將液溫保溫於30至 相而不能分離回收丙烯酸。 -24- 201223939 (比較例2) 實施專利文獻1中的實施例1之再次試驗。 即’將2,〇〇〇g的丙烯酸、l 2〇〇g的dpet、5〇g的 78%之硫酸、1〇g的HQ、2 45〇g的甲苯置入i〇l的燒瓶 中’在60kPa的壓力下、設定於12〇。〇的油浴中加熱， 以縮合水做為與曱苯的共沸水以除去，同時反應1 〇小 時。此時的反應液重量為6,9〇〇g。 在所獲侍的反應液中，加入2,65〇g的2〇%之氫氧化 鈉水溶液並授拌後靜置，獲得6,25Gg的上層（有機相）盘 3,〇〇〇g的下層（水相）。 一從燒瓶抽取該下層（水相）做為中和廢水，進行以下 所示之丙烯酸回收試驗。 使用液相層析法，以鱼管始办丨门这l> 〃 I%例同樣地分析所獲得的 中和廢水時，為含有21 7% Μ π e a 的丙烯酸鈉（相當於16 6%的 丙烯酸）。 在此之前的操作係以記載於蚩 — 钬於專利文獻1的實施例之 1 /1 0的規模實施。 在3 0〇g的所獲得之中和廢_ ^ | γ ， 蜃水中緩緣加入98%之硫酸 直到ΡΗ變成1 8。又，維持硫 爪0夂添加日守的液體之溫度於 2 5至3 〇 〇c。又’所添加的9 8 〇/ -V w· * λ /°之硫酸為3 6 g。接著，雖 將液溫保溫於3 0至3 5 °C ’作因去八龅士。4 丨一因未分離成2相而不能分 離回收丙烯酸。 (實施例4) 在10L的反應器中置入3,〇〇〇g的丙稀酸、16〇〇§的 新戊四醇、70g的㈣之硫酸、7g的MQ、2，⑽〇g的甲 -2 5 - 201223939 苯，在50kPa的壓力下、設定於1〇(rc的油浴中加熱， 除去縮合水同時反應6小時》此時的反應液重量為 6,100g ° 反應結束後，追加3,500g的曱苯。 接著在添加2,950g的20%之氫氧化鈉水溶液並攪拌 後靜置，分離成上層7,650g的（有機相）及49〇〇g的下層 (水相）。 從反應器抽取下層（水相），獲得而做為中和廢水。 與實施例1同樣地分析所獲得的中和廢水之組成結 果為含有29.1 %的丙烯酸鈉（相當於22 3%的丙烯酸）。 再者，針對上層（有機相），在加入】，〇 〇 〇 g的純水並 攪拌後靜置，分離成7,65〇g的上層（有機相）與下層（水 相）將所獲得的上層（有機相）蒸餾除去曱苯，獲得2，15〇吕 的丙烯酸酯（二新戊四醇五丙烯酸酯與六丙烯酸酯的混 合物）。 在450g的上述中所獲得之中和廢水中緩緩加入98〇/〇 之硫駄直到pH變成3 ^又，維持硫酸添加時的液體之溫 度於25至30 C。X，所添加# 98%之硫酸為64.3g。 接著’將液溫保溫於3〇至35t並靜置，分離成上 層（丙烯酸水溶液層）與下層（硫酸鈉水溶液層）。 將分離成2相之液體至分液漏斗，抽取下層（硫酸鈉 水溶液層）。 所獲得的上層之丙烯酸水溶液層為250.lg，丙烯酸 袅度為3 1.0%，相對於中和廢水中所含的丙烯酸，彳回 收7 4.2 %的丙烯酸。 -26- 201223939 再者，針對下層的硫酸鈉水溶液，冷卻至約10°c， 固液分離所析出的結晶之結果為獲得228.7g的含有 36.8%硫酸鈉之結晶與含有67.0g的16.8%丙烯酸、6.6% 硫酸納之水溶液。 (應用例） 將40g的離子交換水置入於反應器中’進行氮封同 時升溫至80°C後，添加ig的10%之過硫酸鈉水溶液。 接著將在2 1 〇g的於實施例2所回收之丙烯酸水溶液中已 溶解5g的次磷酸鈉之單體溶液與1〇g的1〇%之過硫酸 納’維持聚合溫度為8〇〇c，同時從個別的注入口 4小時 連續地滴入反應器中，獲得聚丙烯酸水溶液。 以4 8 %的氫氧化納中和該聚丙稀酸水溶液至ρ η = 7·5 ’獲得固體含量為41·9重量％、黏度為264mpa · s的 聚丙酸鈉水溶液。 [產業上之利用可能性] 可利用於丙烯 丙烯酸酯之製 於丙烯酸酯或 根據本發明的丙烯酸酯之製造方法， 酸酯的製造，較佳為可利用於高沸點的 造，而所分離.回收之丙烯酸則可再利用 聚合物之製造。 . 11欠方法所分離•回收 或聚合物之製造。 又’藉由本發明的丙稀酸之回 之丙歸酸’則可再利用於丙烯酸酯 【圖式簡單說明】 無。 【主要元件符號說明】 無。 -27-Using a liquid chromatograph [Shimadzu Corporation (product), product name LC-10A], the obtained neutralized wastewater was analyzed by absolute line method, containing 32.2% sodium acrylate (equivalent to 24 7 〇 / Astringent acrylic). Further, for the upper layer (organic phase), further, 1,360 g of a 2% by weight aqueous solution of sodium hydroxide is added and allowed to stand, and then allowed to stand, and separated into an upper layer (organic phase ° and lower layer (aqueous phase). In the upper layer ( The organic phase) was added to 4 〇〇g of pure -22-201223939 water and stirred, and then allowed to stand, and separated into 8,660 g of the upper layer (organic phase) and the lower layer (aqueous phase). 1.3 g of hydroquinone monomethyl was added. Ether (hereinafter referred to as "mq") was distilled off under reduced pressure in the obtained upper layer (organic phase) to obtain 2,750 g of acrylate (dipentaerythritol pentaacrylate and hexapropionate). Mixture). Among 300g of the above obtained π > A, hard and hard added 98% sulfuric acid until it becomes ρ Η becomes 3. The added #咖的硫酸为46.9g. Also 'maintains the temperature of the liquid when sulfuric acid is added 25 to 30. (:. Next, the liquid temperature is kept at 30 to 35 t and allowed to stand, and separated into an upper layer (aqueous acrylic acid layer) and a lower layer (sodium sulfate aqueous layer). The liquid separated into two phases is transferred to the liquid separation. In the funnel, extract the lower layer (sodium sulfate aqueous layer). μ The upper layer obtained The aqueous solution of acrylic acid is M65g, the concentration of acrylic acid is 4G.6%, and 80.4% of acrylic acid can be recovered with respect to the acrylic acid contained in the neutralized wastewater. Further, for the lower aqueous solution of sodium sulfate, it is cooled until about 丨, The result of the crystallization of the solid-liquid separation was obtained as an i22 ig aqueous solution containing 37.7% sodium sulphate and 63 § of an aqueous solution containing 135% acrylic acid and 57% sodium sulphate. (Example 2) at 3 〇〇g In the example, 78% sulfuric acid was used until the pH became 3. Further, the sulfuric acid addition day (4) was maintained at 25 to 30. (:. Again, 78% of the added sulfuric acid) 5 9.0g 〇 3 〇 to the messenger layer (aqueous layer of acrylic acid) and the lower layer (sodium sulphate layer) -23- 201223939 The solution separated into two phases was transferred to a separatory funnel, and the lower layer (the aqueous layer of sodium sulphate) was taken. The aqueous acrylic acid layer was 151.8 g, and the propylene concentration was 37.4%. 'According to the acrylic acid contained in the neutralized wastewater, 76.7% of acrylic acid was recovered. (Example 3) 300 g of the wastewater obtained in Example 1 and wastewater Slowly add 9 8 % sulfuric acid until p Η In addition, the temperature of the liquid when the sulfuric acid is added is maintained at 25 to 30 ° C. Further, the 98% sulfuric acid added is 52.1 g 〇 then the liquid temperature is kept at 30 to 35. (: and allowed to stand And separating into an upper layer (aqueous layer of acrylic acid) and a lower layer (sodium sulfate aqueous layer). The solution separated into two phases is transferred to a separatory funnel, and the upper layer of the aqueous solution of acrylic acid obtained by extracting the lower layer (sodium sulfate aqueous layer) is m 4g, the concentration of acrylic acid is 44.6%, and 77.4% of acrylic acid can be recovered relative to the acrylic acid contained in the neutralized wastewater. (Comparative Example 1) 98% of sulfuric acid was gradually added to the wastewater obtained in Example 1 at 3 〇〇g until the pH became 4.2. Furthermore, the temperature of the liquid at the time of sulfuric acid addition is maintained at 25 to 3 (KC. Further, the added 98% sulfuric acid is 32 g 〇 35 ° C, but since it is not separated into 2, then 'the liquid temperature is kept at 30 to the phase. However, the acrylic acid could not be separated and recovered. -24-201223939 (Comparative Example 2) The retest of Example 1 in Patent Document 1 was carried out. That is, '2, 〇〇〇g of acrylic acid, l 2 〇〇g of dpet, 5〇 78% of sulfuric acid, 1〇g of HQ, and 2,45 g of toluene of g were placed in a flask of i〇l', set at 12 Torr under a pressure of 60 kPa. Heated in an oil bath of hydrazine, made with condensed water It is azeotropic water with toluene to remove and react for 1 hour. The weight of the reaction solution at this time is 6,9 〇〇g. In the reaction solution obtained, 2,65 〇g of 2% by weight is added. The aqueous sodium hydroxide solution was allowed to stand and allowed to stand to obtain 6,25 Gg of the upper (organic phase) disk 3, and the lower layer of the 〇〇〇g (aqueous phase). The lower layer (aqueous phase) was extracted from the flask as neutralization wastewater. Carry out the acrylic acid recovery test shown below. Using liquid chromatography, the fish tube is used to start the sputum. The 〃I% case is analyzed in the same manner as the obtained neutralization wastewater. Sodium acrylate (corresponding to 16 6% of acrylic acid) containing 21 7% of Μ π ea. The operation before this was carried out on the scale of 1 / 10 of the example described in Patent Document 1. 0〇g is obtained in the middle and waste _ ^ | γ , 98% sulfuric acid is added to the buffer in the sputum water until the sputum becomes 18. 8. Further, the temperature of the liquid added to the sulphur claw 0 夂 is increased to 25 to 3 〇 〇c. Also, the added 9 8 〇 / -V w · * λ / ° sulfuric acid is 3 6 g. Then, although the liquid temperature is kept at 30 to 35 ° C 'cause to go to eight gentlemen. 4 丨 The separation of acrylic acid could not be separated because it was not separated into two phases. (Example 4) 3, 〇〇〇g of acrylic acid, 16 〇〇 of neopentyl alcohol, 70 g were placed in a 10 L reactor. (4) Sulfuric acid, 7 g of MQ, 2, (10) 〇g of A-2 5 - 201223939 benzene, set at 1 Torr under a pressure of 50 kPa (heating in rc oil bath, removing condensation water and reacting for 6 hours) The weight of the reaction liquid at the time of the reaction was 6,100 g. After the completion of the reaction, 3,500 g of toluene was added. Then, 2,950 g of a 20% aqueous sodium hydroxide solution was added and stirred, and then allowed to stand, and separated into an upper layer of 7,650 g ( The lower phase (aqueous phase) of 49 〇〇g and the lower layer (aqueous phase) of 49 〇〇g. The lower layer (aqueous phase) was taken out from the reactor and obtained as neutralization wastewater. The composition of the obtained neutralized wastewater was analyzed in the same manner as in Example 1. Contains 29.1% sodium acrylate (corresponding to 22 3% acrylic acid). Further, for the upper layer (organic phase), after adding 〇〇〇g of pure water and stirring, it is allowed to stand and separated into 7,65 〇g. The upper layer (organic phase) and the lower layer (aqueous phase) are subjected to distillation of the obtained upper layer (organic phase) to remove toluene to obtain a 2,15 ruthenium acrylate (a mixture of dipentaerythritol pentaacrylate and hexaacrylate) ). The sulfur enthalpy of 98 Å/〇 was gradually added to the wastewater obtained in the above-mentioned 450 g of the above-mentioned wastewater until the pH became 3 Ω, and the temperature of the liquid at the time of the addition of sulfuric acid was maintained at 25 to 30 C. X, the added 98% sulfuric acid was 64.3 g. Next, the liquid temperature was kept at 3 to 35 t and allowed to stand, and separated into an upper layer (aqueous acrylic acid layer) and a lower layer (sodium sulfate aqueous layer). The liquid separated into two phases was passed to a separatory funnel, and the lower layer (aqueous sodium sulfate aqueous layer) was taken. The upper aqueous acrylic acid layer obtained was 250. lg, and the acrylic acid enthalpy was 3 1.0%, and 74.2% of acrylic acid was recovered relative to the acrylic acid contained in the neutralized wastewater. -26- 201223939 Furthermore, the lower layer of sodium sulfate aqueous solution was cooled to about 10 ° C, and the crystals precipitated by solid-liquid separation were obtained as follows: 228.7 g of crystals containing 36.8% of sodium sulfate and 67.0 g of 16.8% of acrylic acid were obtained. , 6.6% aqueous solution of sodium sulphate. (Application example) 40 g of ion-exchanged water was placed in a reactor. The temperature was raised to 80 ° C while nitrogen sealing, and then 10% aqueous sodium persulfate solution of ig was added. Next, 2 g of the monomer solution of sodium hypophosphite dissolved in the aqueous solution of acrylic acid recovered in Example 2 and 1 〇g of 1% by weight of sodium persulfate were maintained at a polymerization temperature of 8 〇〇c. At the same time, it was continuously dropped into the reactor from an individual injection port for 4 hours to obtain an aqueous polyacrylic acid solution. The aqueous polyacrylic acid solution was neutralized with 48% sodium hydroxide to ρ η = 7·5 ' to obtain an aqueous sodium polypropionate solution having a solid content of 41.9 wt% and a viscosity of 264 mPa·s. [Industrial Applicability] It can be used in the production of acrylate or acrylate or acrylate according to the present invention. The production of an acid ester is preferably carried out at a high boiling point. The recovered acrylic acid can be reused for the manufacture of polymers. . 11 Isolation of methods • Recycling or polymer manufacturing. Further, the acrylic acid of the acrylic acid of the present invention can be reused in the acrylate [simplified description of the drawing]. [Main component symbol description] None. -27-