1322803 九、發明說明： 【發明所屬之技術領域】 本發明係關於對苯二曱酸之製造方法，詳而 於適於作為聚對苯二曱酸乙二酯等聚酯之製造 二曱酸之製造方法。本發明亦包括利用該方法 度分佈範圍狹窄之對苯二曱酸。 【先前技術】 藉由對二曱苯之氧化所得到的粗對笨二甲酸 含有較大量之4 -羧基苯曱醛，（簡稱為「4CBA_ 純物，將此精製之後，作為聚酯的原料使用。 作為此種粗對苯二曱酸之精製方法，將粗對 解於水性溶媒，在高壓·高溫下使之與白金族 觸而精製的方法係屬周知（例如日本專利特開 號公報），此外還有許多方法係屬已知。 作為對二曱苯之氧化反應，通常使用使對二 溶媒中，在例如包含鈷、錳以及溴的觸媒存在 〜2 3 0 °C之溫度條件使之與分子狀氧反應之方：¾ 所得之對笨二甲酸，通常含有以重量基準計之 1 0 0 0 0 ρ p m之4 -羧基笨曱醛作為不純物。將此對 水混合，成為1 0〜4 0重量百分比之漿體。接著 由升壓泵由反應壓力加壓至偏高若干量的壓力 熱溶解步驟，作為對苯二曱酸水溶液。 使此對苯二曱酸水溶液通過充填有含白金族 媒之塔型反應器。作為含有白金族金屬的觸媒1 312XP/發明說明書(補件)/93-11/93123420 言之'係關 原料之對苯 所製造之粒 之中，通常 )等各種不 苯二甲酸溶 金屬觸媒接 Ψ 6-329583 甲苯在醋酸 下，以1 7 0 i：。藉此方法 1 0 0 0 -苯二甲酸與 ，此漿體藉 ，被送往加 金屬之觸 例如有纪、 5 1322803 f，並於前述旋轉軸f的下端部裝設例如傾斜槳葉等攪拌翼 g，同時於前述晶析槽e的内側面設置妨礙板d，且進一步 在前述攪拌翼g的前端附近設置碰撞板ίι之裝置。 於習知的晶析裝置中，藉由攪拌翼的旋轉，在攪拌翼的 前端部產生對苯二曱酸水溶液的旋轉流動，其結果會有在 攪拌翼中央部之晶析槽内底面的中央部產生漿體停滯阻塞 的問題。 另一方面，近年來使用以使對笨二甲酸與二醇類直接反 應的所謂直接聚合法來製造聚酯，特別是製造聚對苯二曱 酸乙二酯的方法。於此直接聚合法中，對笨二甲酸與乙二 醇等二醇類混合而以漿體的狀態被送往反應系統，供進行 化學反應。於此時之製程中，隨著對笨二曱酸粒子之粒徑 分佈或平均粒子徑值的不同，會大幅影響對苯二甲酸之處 理、輸送、與乙二醇類之混合性以及反應均勻性。 一般而言，具有由大粒徑到小粒徑區域之寬廣範圍粒度 分佈者，有提高與乙二醇類之漿體特性的傾向，在與乙二 醇類之混合性方面佳，平均粒徑通常在5 0〜1 5 0 m的範 圍。又，相反地若粒徑超過2 5 0 // m的大粒徑粒子的比率增 加太多時，進行直接聚合法時對苯二甲酸容易作為未反應 分而殘留，結果必需延長反應時間，因而已被確認會有副 產物增加等問題。另一方面，粒徑小於5 0 " m的微粉的比 例增加太多的話，已被確認會有製品的處理、或輸送時間 變長等問題。 因此，完全滿足對苯二曱酸的處理、輸送、與乙二醇類 7 312XP/發明說明書(補件)/93-11/93123420 1322803 之混合性以及反應的均勻性等要求之對苯二甲酸之製 困難的，隨著使對苯二甲酸與二醇類直接反應的所謂 聚合法的設備之裝置、規模、運轉方法等的不同，亦 要求的品質不同的情形。 【發明内容】 本發明的目的在於提供藉由防止在晶析槽内底面中 部發生漿體的停滯，而有效率且直接於晶析槽做出所 的對苯二甲酸粒子的粒度分佈之對苯二甲酸之製造方 本發明亦提供利用該方法所製造之粒度分佈範圍狹窄 苯二甲酸。 本發明提供了例如以下方法。 ο)—種對苯二曱酸之製造方法，係於自對苯二曱s 水性溶液晶析對苯二甲酸時，使用設置使攪拌翼接近 面之攪拌機，同時在晶析槽的内側面設置在上下方向 之妨礙板之晶析裝置。 (2) 如前述（1)之對苯二甲酸之製造方法，其特徵為 攪拌翼之形狀係被形成為在前述晶析槽的中央部側為 方向長度較長，隨著朝向該晶析槽的周邊部，其上下 之長度緩緩縮短之板狀。 (3) 如前述（1)或（2)之對苯二曱酸之製造方法，其与 為使連接於前述晶析槽之對笨二曱酸水性溶液的流入 口’形成為朝向該晶析槽内的上方向。 (4) 如前述（1)〜（3)中任一項之對苯二曱酸之I 方法，其中，前述攪拌翼之下端與前述晶析槽内底面 312XP/發明說明書(補件)/93-11/93123420 造是 直接 有所 央 要求 法。 之對 【之 内底 延伸 前述 上下 方向 F徵 管開 L造 之間 8 1322803 的間隙（clearance)c與前述授拌翼的翼徑R之比c/R在 0.005〜0.10之範圍内。 (5) 如前述（1)〜（4)中任一項之對苯二甲酸之製造方 法，其特徵為利用由被串聯連接的複數個晶析槽所構成， 且具有使攪拌翼接近内底面之攪拌機，同時在晶析槽的内 側面設置在上下方向延伸之妨礙板之晶析槽，使對苯二甲 酸晶析出總晶析量之至少5 0重量％。 (6) 如前述（1)〜（5)中任一項之對笨二曱酸之製造方 法，其特徵為第1晶析槽之攪拌翼所提供之攪拌動力為 0· 01〜10kw/m3 。 (7) 如前述（2)之對苯二甲酸之製造方法，其特徵為令 第1晶析槽之内徑為D、翼徑為R時，使用攪拌之翼徑R 為（0.3〜0.8)D，且翼之形狀在中央部側上下方向的長度 為（0.1〜3·0) R，且翼前端部在上下方向之長度為（0〜 0 · 5 ) R之複數片攪拌翼。 (8) 如前述（1)〜（7)中任一項之對苯二曱酸之製造方 法，其特徵為使粗對苯二甲酸溶解於水性溶媒，在2 6 0〜 3 2 ◦ °C的溫度條件下，使之與白金族金屬觸媒接觸而精製， 並於自該對苯二甲酸水性溶液以串聯連接的複數晶析槽階 段性地冷卻而晶析時，將第1晶析槽之晶析溫度設為2 4 0 〜260 °C，攪拌翼之攪拌動力於0.01〜10kw/m3的範圍内進 行攪拌，接著將第2晶析槽之晶析溫度設為1 8 0〜2 3 0 °C ， 且使該晶析溫度比第1晶析槽的晶析溫度低2 0〜6 0 °C 。 (9) 如前述（1)〜（8)中任一項之對苯二曱酸之製造方 9 312XP/發明說明書(補件)/93-11/93123420 1322803 法，其特徵為藉由變更攪拌動力而變更攪拌翼之旋轉數， 做出對苯二曱酸顆粒之粒度分佈。 (1 0 ) —種對苯二曱酸，其特徵為平均粒徑為5 0〜1 5 0 " m，其標準差為30〜50。 (1 1 ) 一種對苯二曱酸，其特徵係由前述（1 )〜（9 )中任一 項之製造方法所製造，平均粒徑為5 0〜1 5 0 // m，其標準差 為3 0〜5 0。 以下依照圖1說明本發明之第1實施形態。圖1係於晶 析槽頂設置馬達之例，但設置於晶析槽底亦可。 1表示晶析槽，在該晶析槽1内之中央部垂下設置旋轉 軸2，在該旋轉軸2的下端部安裝攪拌翼3。 在此，該攪拌翼3之複數片之各翼體3a，在接近前述旋 轉軸2的根部側的上下方向寬度較大，隨著朝向前端側其 寬度緩緩減少而成為約略梯形之板狀，各翼體3a被安裝成 其下端接近於前述晶析槽1之内底面。 亦即，其特徵在於令晶析槽之内徑為D、翼徑為R時， 攪拌之翼徑R為（0.3〜0.8) D，較佳為（0.4〜0.6) D， 而且，翼之形狀在中央部側上下方向的長度為（0. 1〜3. 0 ) R，較佳為（0.3〜0.7) R，更佳為（0.4〜0.6) R，而且使 用翼前端部在上下方向之長度為（〇〜〇.5)R、較佳為（0.1 〜0.3) R之複數片攪拌翼。 攪拌翼下端與前述晶析槽内底面之間的間隙c與前述攪 拌翼的翼徑R之比c / R在0 · 0 0 5〜0 . 1 0之範圍内，較佳為 0.01〜0.05、更佳為0.01〜0.03之範圍内。 10 312XP/發明說明書(補件)/93-11/93123420 1322803 又，在該晶析槽1的内側面固定有上下方向延伸之 妨礙板4，該妨礙板4之下端接近於該晶析槽1之内；ί 使用串聯連接的複數個晶析槽製造對苯二甲酸之情 況，係使用具有使攪拌翼接近内底面之攪拌機、同時 析槽的内側面設置在上下方向延伸之妨礙板之晶析槽 對苯二f酸晶析出總晶析量之至少5 0重量％、較佳為 重量％。 於圖1中，5表示連接於前述晶析槽1之對苯二甲 溶液之流入管，6表示連接於該晶析槽1之該水溶液 出管。 如此，若藉由馬達（未圖示）的驅動使旋轉軸2驅 轉而旋轉其下端接近晶析槽1内底面的攪拌翼3，該 槽1内的對苯二甲酸水溶液於該晶析槽1的中央下方 由在根部側上下寬度較大的各翼體3a押壓，同時藉由 前端部上下寬度越小的各該翼體3 a，沿著晶析槽1的 面流向集中的外方，其後，水溶液成為沿著其下端接 述内底面的妨礙板4的速度較快之上升流，其後朝向 槽1的中心部流動之後於該中心部成為下方流，成為 流C。 此處所實施之運轉條件為：晶析槽1之攪拌所需動 0.01〜10kw/m3為佳，較佳為0.1〜1.0kw/m3，該攪拌 動力係在0.15〜0.7kw/m3之範圍實施。 故，水溶液於前述晶析槽1之内底面中央部成為漿 不會停滯，同時於該晶析槽1之内側面附近的周緣部 312XP/發明說明書(補件)/93-11/93123420 複數 篆面。 在晶 ，使 70 酸水 之流 動旋 晶析 部藉 越往 内底 近前 晶析 循環 力以 所要 體而 成為 11 1322803 速度較快的上升流而不會發生不均勻的結晶化，可有效率 地得到均勻粒徑的結晶。 接著，因如前所述無漿體的停滯，所以低速旋轉攪拌翼 3也不會發生漿體的停滯，因而可在寬廣的範圍内控制該 攪拌翼3的旋轉數，因此可以控制停滯時間或分級效果， 可人為製造具有均勻粒徑分佈或有各種不同粒徑的結晶。 例如，可以獲得具有平均粒徑為5 0〜1 5 0 // m、較佳為 8 0〜1 1 0 // m的範圍，其標準差為3 0〜5 0之狹窄粒度分佈 之對苯二甲酸。例如在該情況，授拌動力為0 . 0 1〜 10kw/m3，較佳為 0.1〜1.0kw/m3。 標準差係由以下公式求出。即， 令X為平均值、s為標準差、Xo為代表值、h為區間寬、 f為自由度、N為資料數、u = ( X - Xo)/h時，成為以下 關係： 平均值：X=Xo+ E(uxf)/Nxh 標準差：s = h x /"(1/(N-1) χ {Σ(ια2 x f) - (Euf): / N }) 另外，於此實施形態中係顯示攪拌翼3由6片翼體3 a 形成之例，但不以此為限，亦可由2片以上之複數片翼體 3 a形成攪拌翼。 又，較佳之對苯二曱酸之製造方法為：使粗對苯二曱酸 溶解於水性溶媒，在2 6 0〜3 2 0 °C的溫度條件下，使之與白 金族金屬觸媒接觸而精製，自該對苯二曱酸之水性溶液以 串聯連接的複數個晶析槽階段性地冷卻而晶析出對笨二曱 12 312XP/發明說明書(補件)/93-] ]/93]23420 1322803 酸時，第1晶析槽之晶析溫度設為2 4 0〜2 6 0 °C，攪拌翼之 攪拌動力以0. 01〜10kw/m3的範圍進行攪拌，接著第2晶 析槽之溫度為1 8 0〜2 3 0 °C。 此情況，以藉由變更攪拌動力使第2晶析槽之晶析溫度 比第1晶析槽的晶析溫度低2 0〜6 0 °C，並使第2晶析槽之 晶析溫度為1 8 0〜2 3 0 °C為佳。 圖2顯示本發明之第2實施形態，於此實施形態中，係 使前述第1實施形態之晶析槽1之流入管5的前端部在該 晶析槽1内朝上方曲折成形，以使該流入管5的開口 5a 朝向上方而形成，同時，流出管6也使前端部在該晶析槽 1内朝上方曲折成形，以使該流出管6的開口 6a朝向上方 而形成。 如此，對苯二甲酸水溶液，由流入管5的開口 5 a朝向 上方流入在晶析槽1内的周邊在上方流動的溶液中，蒸汽 不會直接附著於翼面，所以攪拌翼3之水溶液吐出效率不 會降低，又，流出管6的開口 6 a也朝向上方，所以在晶析 槽1内周邊部上升的水溶液不會直接流入排出，可以增長 滯留時間，同時在到達開口 6的上方的水溶液中晶析出的 結晶往下流，流入該開口 6 a，並由排出管6排出》如此， 可得指定粒徑以上之均勻的結晶。 圖3顯示本發明之第3實施形態，於此實施形態中，係 使前述第1實施形態之流入管5的前端部在該晶析槽1内 朝上方曲折成形，以使該流入管5的開口 5a朝向上方形 成，同時在該開口 5 a的上方設置逆圓錐狀的水流分散體 13 312XP/發明說明書(補件)/93-11/93123420 1322803 5b，又，使流出管6的前端部朝下方曲折成形，封 端部的端面，同時在該前端部的側面形成朝對向於 析槽1的内側面的方向之開口 6 b。 如此，對苯二甲酸水溶液由流入管5的開口 5a > 流出後藉由逆圓錐狀的水流分散體5b分散，分散並 析槽1内的水溶液中，所以可防止蒸汽對翼面的附 攪拌翼3之水溶液吐出效率可以提高，同時可以得 流入的能量之初期分散作用。又，流出管6的開口 可將在晶析槽1的内底面周邊部結晶化的粒子分級 溶液一起上升者與不隨之上升者的位置，所以可在 口 6b以負壓吸取指定粒徑以上的結晶粒子。 【實施方式】 以下依照實施例說明本發明，但本發明並不限於 例。 〈實施例〉 (實施例1 ) 發明人具體說明前述之習知的製造裝置，與本發 3實施形態之製造裝置在連續運轉時之實驗。 調整粒徑分佈為7 4〜1 4 9 /z m的高純度對苯二曱2 漿體，自將該漿體在溶解槽中加壓並於2 2 0 °C下完 之對苯二甲酸水溶液，使用相同容量的3個串聯連 析槽進行晶析。 此情況，令第1晶析槽之内徑為D、翼徑為R時 用攪拌之翼徑R為〇. 5 D，且翼之形狀在中央部側上 312ΧΡ/發明說明書(補件)/93-11 /93丨23420 閉該前 前述晶 fe上方 流入晶 著，由 到利用 6 b位於 為隨水 前述開 實施 明之第 ιέ之水 全溶解 接的晶 ，係使 下方向 14 1322803 的長度為0.5R，且翼前端部在上下方向之長度為0.15R之 六片翼片所構成的攪拌翼。攪拌翼之下端與晶析槽内底面 之間的間隙c與攪拌翼的翼徑R之比c / R為0. 0 2。又，旋 轉數係可改變，以0 . 2以及0 . 7 k w / m3進行晶析。另一方面， 第2晶析槽使用具有4片翼之傾斜槳葉翼之攪拌翼，固定 攪拌動力為0.7kw/m3。 第1晶析槽與第2晶析槽的溫度，以分別使之析出對苯 二曱酸總析出量的約7 0重量％與約9 9重量％的方式管理第 1晶析槽溫度為1 6 0°C、第2晶析槽溫度為1 2 0 °C ，第3晶 析槽係以溫度控制於1 0 0 °C的方式進行溫度管理。 列示關於對苯二曱酸粒子之物性試驗的結果。於圖6 中，實施例與比較例之不同在於，比較例使用翼徑為0. 5 D 的傾斜槳葉翼，其他運轉條件則全部與·實施例相同。另外， 粒徑係使用雷射繞射‘散射式粒度分佈測定裝置。 攪拌動力為0 . 2 k w / m3時之平均粒徑為1 9 0 . 7 // m，標準 差為61.1。又，攪拌動力為0.7kw/m3時之平均粒徑為134 "m，標準差為4 6 . 9，可知獲得粒度分佈狹窄之對苯二甲 酸。 (產業上之可利用性） 根據如此之本發明，可有效率地獲得對笨二甲酸結晶， 此外具有可控制結晶粒徑的效果。 【圖式簡單說明】 圖1係本發明之第1實施形態之剖面圖。 圖2係本發明之第2實施形態的重要部位之剖面圖。 15 312XP/發明說明書(補件)/93-11/93123420 1322803 圖3係本發明之第3實施形態的重要部位之剖面圖。 圖4係習知的製造裝置之1例之剖面圖。 圖5係習知的製造裝置之其他例之剖面圖。 圖6係顯示本發明之製造裝置與習知之製造裝置之晶析 槽内之攪拌動力與對苯二甲酸之粒度分佈關係之圖。 【主要元件符號說明】 1 晶 析 槽 2 旋 轉 轴 3 攪 拌 翼 3a 翼 體 4 妨 礙 板 5 流 入 管 5a 開 D 5b 水 流 分 6 流 出 管 6 a , 6b開 σ a 攪 拌 槽 b 旋 轉 軸 c 攪 拌 翼 d 妨 礙 板 e 晶 析 槽 f 旋 轉 軸 g 攪 拌 翼 h 碰 撞 板 16 312XP/發明說明書(補件)/93-11/931234201322803 IX. Description of the Invention: [Technical Field of the Invention] The present invention relates to a method for producing terephthalic acid, which is suitable for the production of diterpenic acid as a polyester such as polyethylene terephthalate. Production method. The present invention also encompasses the use of this method for the narrow distribution of terephthalic acid. [Prior Art] The crude para-dicarboxylic acid obtained by the oxidation of diphenylbenzene contains a relatively large amount of 4-carboxybenzaldehyde (referred to as "4CBA_ pure substance, and after this purification, it is used as a raw material of polyester. As a method for purifying such crude terephthalic acid, a method of resolving a crude solution in an aqueous solvent and purifying it with a platinum group under high pressure and high temperature is known (for example, Japanese Patent Laid-Open Publication). In addition, many methods are known. As an oxidation reaction to dinonylbenzene, it is usually used in a solvent of, for example, a catalyst containing cobalt, manganese, and bromine at a temperature of 〜30 ° C. The reaction with molecular oxygen: 3⁄4 of the obtained p-dicarboxylic acid, usually containing 1 - carboxy quinolaldehyde of 1 0 0 0 ρ pm on the basis of weight as an impurity. This water is mixed to become 1 0~ 40% by weight of the slurry, which is then pressurized by the booster pump from the reaction pressure to a higher amount of the pressure hot dissolution step as an aqueous solution of terephthalic acid. The aqueous solution of the terephthalic acid is filled with platinum. Tower-type reactor. Catalysts containing iridium metal 1 312XP / invention manual (supplement) / 93-11/93123420 "In the granules made of benzene by the raw materials, usually), etc. Media connection - 6-329583 Toluene in acetic acid, to 1 7 0 i:. By this method 1 0 0 0-phthalic acid, the slurry is borrowed, sent to the metal touch, such as Yuki, 5 1322803 f An agitating blade g such as an inclined blade is attached to the lower end portion of the rotating shaft f, and an obstruction plate d is provided on the inner side surface of the crystallization tank e, and a collision plate is further provided near the front end of the agitating blade g. In a conventional crystallization apparatus, a swirling flow of a terephthalic acid aqueous solution is generated at the tip end portion of the stirring blade by the rotation of the stirring blade, and as a result, it is present in the crystallization tank at the center of the stirring blade. In the central portion of the bottom surface, there is a problem that the slurry is stagnant and blocked. On the other hand, in recent years, a so-called direct polymerization method for directly reacting a dibenzoic acid with a glycol is used to produce a polyester, particularly a polyterpene phthalic acid. Method of ethylene diester. In this direct polymerization method Mixing benzoic acid with a glycol such as ethylene glycol and sending it to the reaction system in a slurry state for chemical reaction. In this process, along with the particle size distribution of the doecic acid particles or The difference in average particle diameter value will greatly affect the treatment, transport, and miscibility of ethylene terephthalate and reaction uniformity. Generally, it has a wide range of particle size from large particle size to small particle size region. The distributor has a tendency to improve the properties of the slurry with ethylene glycol, and is excellent in the compatibility with ethylene glycol, and the average particle diameter is usually in the range of 50 to 150 m. When the ratio of the large-sized particles having a diameter of more than 250 k is increased too much, the terephthalic acid is likely to remain as an unreacted component in the direct polymerization method, and as a result, it is necessary to lengthen the reaction time, and thus it has been confirmed that there is a vice Product increases and other issues. On the other hand, if the ratio of the fine powder having a particle diameter of less than 50 " m is too large, it has been confirmed that there is a problem that the processing of the product or the transportation time becomes long. Therefore, the terephthalic acid which satisfies the requirements for the treatment and transportation of terephthalic acid, and the compatibility with the ethylene glycol 7 312XP/invention specification (supplement)/93-11/93123420 1322803 and the uniformity of the reaction are fully satisfied. The production is difficult, and the quality, the size, the operation method, and the like of the apparatus for directly reacting terephthalic acid with a diol are also required to have different qualities. SUMMARY OF THE INVENTION An object of the present invention is to provide a benzene which can efficiently and directly form a particle size distribution of terephthalic acid particles by directly preventing stagnation of a slurry in a middle portion of a bottom surface of a crystallization tank. The manufacturer of dicarboxylic acid The present invention also provides a narrow range of phthalic acid having a particle size distribution range produced by the method. The present invention provides, for example, the following method. ο) - a method for producing terephthalic acid, in the case of crystallization of terephthalic acid from an aqueous solution of p-benzoquinone s, using a stirrer provided with a stirring blade close to the surface while being disposed on the inner side of the crystallization tank A crystallization device for obstructing the plate in the up and down direction. (2) The method for producing terephthalic acid according to the above (1), characterized in that the shape of the stirring blade is formed so that the direction length is long on the central portion side of the crystallization tank, and the crystallization tank is oriented toward the crystallization tank In the peripheral portion, the length of the upper and lower sides is gradually shortened. (3) The method for producing terephthalic acid according to the above (1) or (2), which is formed so as to form an inflow port for the aqueous solution of the styric acid which is connected to the crystallization tank toward the crystallization The upper direction inside the slot. (4) The method of the terephthalic acid according to any one of the above (1) to (3), wherein the lower end of the agitating blade and the bottom surface 312XP of the crystallization tank/invention specification (supplement)/93 -11/93123420 Build is a direct request. The ratio of the clearance c between the upper and lower directions of the upper and lower directions of the upper and lower directions of the F, 8 1322803 and the wing diameter R of the aforementioned mixing wings is in the range of 0.005 to 0.10. (5) The method for producing terephthalic acid according to any one of the above (1) to (4) characterized by comprising a plurality of crystallization tanks connected in series, and having a stirring blade close to the inner bottom surface In the mixer, a crystallization tank of the interference plate extending in the vertical direction is provided on the inner side surface of the crystallization tank to crystallize the terephthalic acid to at least 50% by weight of the total crystallization amount. (6) The method for producing a bismuthic acid according to any one of the above (1) to (5), characterized in that the stirring power provided by the stirring blade of the first crystallization tank is 0·01 10 10 kw/m 3 . (7) The method for producing terephthalic acid according to (2) above, wherein when the inner diameter of the first crystallization tank is D and the wing diameter is R, the wing diameter R using the stirring is (0.3 to 0.8). D, and the shape of the wing is a length of (0.1 to 3·0) R in the vertical direction of the center portion side, and a plurality of agitating blades having a length of the tip end portion in the vertical direction of (0 to 0 · 5 ) R. (8) The method for producing terephthalic acid according to any one of the above (1) to (7) characterized in that the crude terephthalic acid is dissolved in an aqueous solvent at 2 6 0 to 3 2 ◦ ° C Under the temperature condition, it is refined by contact with the platinum metal catalyst, and the first crystallization tank is crystallized when the aqueous solution of the terephthalic acid is cooled in stages by a plurality of crystallization tanks connected in series. The crystallization temperature is set to 2 4 0 to 260 ° C, the stirring power of the stirring blade is stirred in the range of 0.01 to 10 kw/m 3 , and then the crystallization temperature of the second crystallization tank is set to 1 8 0 to 2 3 0 ° C, and the crystallization temperature is lower than the crystallization temperature of the first crystallization tank by 20 to 60 ° C. (9) The method for producing terephthalic acid according to any one of the above (1) to (8), 9 312 XP / invention specification (supplement) / 93-11/93123420 1322803, characterized by changing stirring The number of rotations of the stirring blades was changed by the power to make a particle size distribution of the terephthalic acid particles. (10) a terephthalic acid characterized by an average particle diameter of 50 to 1 50 and a m with a standard deviation of 30 to 50. (1 1 ) A terephthalic acid, which is produced by the production method according to any one of the above (1) to (9), having an average particle diameter of from 50 to 1 50 // m, and a standard deviation thereof It is 3 0~5 0. Hereinafter, a first embodiment of the present invention will be described with reference to Fig. 1 . Fig. 1 is an example in which a motor is disposed at the top of the crystallizing tank, but it may be provided at the bottom of the crystallizing tank. Reference numeral 1 denotes a crystallization tank, and a rotary shaft 2 is provided at a central portion of the crystallization tank 1, and a stirring blade 3 is attached to a lower end portion of the rotary shaft 2. Here, each of the wing bodies 3a of the plurality of the agitating blades 3 has a large width in the vertical direction close to the root side of the rotating shaft 2, and gradually decreases in width toward the distal end side to form a substantially trapezoidal plate shape. Each of the wing bodies 3a is mounted such that its lower end is close to the inner bottom surface of the aforementioned crystallization vessel 1. That is, when the inner diameter of the crystallization tank is D and the wing diameter is R, the wing diameter R of the stirring is (0.3 to 0.8) D, preferably (0.4 to 0.6) D, and the shape of the wing The length in the vertical direction of the central portion side is (0.1 to 3.0) R, preferably (0.3 to 0.7) R, more preferably (0.4 to 0.6) R, and the length of the tip end portion in the up and down direction is used. A plurality of stirring wings of (〇~〇.5)R, preferably (0.1 to 0.3) R. The ratio c / R of the gap c between the lower end of the stirring blade and the bottom surface of the crystallization tank to the wing diameter R of the agitating blade is in the range of 0·0 0 5 to 0.10, preferably 0.01 to 0.05. More preferably, it is in the range of 0.01 to 0.03. 10 312XP/Invention Manual (Supplement)/93-11/93123420 1322803 Further, an interference plate 4 extending in the vertical direction is fixed to the inner surface of the crystallization tank 1, and the lower end of the interference plate 4 is close to the crystallization tank 1 In the case of producing terephthalic acid by using a plurality of crystallization tanks connected in series, the crystallization of the barrier plate having the stirring side of the stirring blade close to the inner bottom surface and the inner side surface of the grooving groove extending in the vertical direction is used. The groove is preferably at least 50% by weight, preferably % by weight, based on the total crystallization of the benzenedifluoride. In Fig. 1, reference numeral 5 denotes an inflow pipe of a terephthalic acid solution connected to the crystallization vessel 1, and 6 denotes an aqueous solution outlet pipe connected to the crystallization vessel 1. As described above, when the rotating shaft 2 is driven by the driving of a motor (not shown) to rotate the stirring blade 3 whose lower end is close to the bottom surface of the crystallization vessel 1, the aqueous solution of terephthalic acid in the tank 1 is in the crystallization tank. The lower center of the first portion is pressed by the respective wing bodies 3a having a large vertical width on the root side, and each of the wing bodies 3a having a smaller vertical width at the front end portion flows toward the concentrated outer side along the surface of the crystallization tank 1. Then, the aqueous solution becomes a rising flow of the interference plate 4 which is connected to the inner bottom surface along the lower end thereof, and then flows toward the center portion of the groove 1 and then flows downward in the center portion to become the flow C. The operating conditions to be carried out here are preferably 0.01 to 10 kw/m3 of the stirring required for the crystallization tank 1, preferably 0.1 to 1.0 kw/m3, and the stirring power is carried out in the range of 0.15 to 0.7 kW/m3. Therefore, the aqueous solution does not stagnate in the center portion of the inner bottom surface of the crystallization tank 1, and the peripheral portion 312XP near the inner side surface of the crystallization tank 1/invention specification (supplement)/93-11/93123420 plural 篆surface. In the crystal, the flow crystallization of the 70 acid water is circulated to the inner bottom, and the crystallization time of the crystallization is increased to 11 1322803, which is a fast rising flow without uneven crystallization. A crystal of uniform particle size is obtained. Then, since there is no stagnation of the slurry as described above, the slurry of the low-speed rotating agitating blade 3 does not stagnate, so that the number of rotations of the agitation blade 3 can be controlled over a wide range, so that the stagnation time can be controlled or The grading effect makes it possible to artificially produce crystals having a uniform particle size distribution or having various particle diameters. For example, a benzene having a narrow particle size distribution with an average particle diameter of 50 to 150/m, preferably 80 to 11.0/m, and a standard deviation of 30 to 50 can be obtained. Dicarboxylic acid. For example, in this case, the mixing power is from 0.01 to 10 kw/m3, preferably from 0.1 to 1.0 kw/m3. The standard deviation is obtained by the following formula. That is, when X is the average value, s is the standard deviation, Xo is the representative value, h is the interval width, f is the degree of freedom, N is the number of data, and u = (X - Xo)/h, the following relationship is obtained: :X=Xo+ E(uxf)/Nxh Standard deviation: s = hx /"(1/(N-1) χ {Σ(ια2 xf) - (Euf): / N }) In addition, in this embodiment The example in which the agitating blades 3 are formed of six wing bodies 3 a is shown, but not limited thereto, the agitating blades may be formed by two or more pieces of the wing bodies 3 a . Further, the preferred method for producing terephthalic acid is to dissolve the crude terephthalic acid in an aqueous solvent and contact it with a platinum metal catalyst at a temperature of 2600 to 3200 °C. And refining, the aqueous solution of the terephthalic acid is cooled in stages by a plurality of crystallization tanks connected in series to crystallize out to the stupid 12 312XP/invention specification (supplement)/93-]]/93] 23420 1322803 When the acid is used, the crystallization temperature of the first crystallization tank is set to 2 4 0 to 2 60 ° C, and the stirring power of the stirring blade is stirred in the range of 0.01 to 10 kw/m 3 , followed by the second crystallization tank. The temperature is 1 800 ° 2 3 0 ° C. In this case, by changing the stirring power, the crystallization temperature of the second crystallization tank is lower than the crystallization temperature of the first crystallization tank by 20 to 60 ° C, and the crystallization temperature of the second crystallization tank is 1 8 0~2 3 0 °C is preferred. Fig. 2 shows a second embodiment of the present invention. In this embodiment, the tip end portion of the inflow pipe 5 of the crystallization vessel 1 of the first embodiment is bent in the crystallization tank 1 so as to be bent upward. The opening 5a of the inflow pipe 5 is formed upward, and the outflow pipe 6 is also formed by bending the tip end portion in the crystallization tank 1 upward so that the opening 6a of the outflow pipe 6 faces upward. In this way, the aqueous solution of terephthalic acid flows into the solution flowing upward in the periphery of the crystallization tank 1 from the opening 5a of the inflow pipe 5, and the steam does not directly adhere to the airfoil surface, so the aqueous solution of the stirring blade 3 is discharged. Since the efficiency is not lowered, and the opening 6a of the outflow pipe 6 is also directed upward, the aqueous solution rising in the peripheral portion of the crystallization vessel 1 does not directly flow into and out, and the residence time can be increased while the aqueous solution reaching the opening 6 is reached. The crystals precipitated by the mesocrystals flow downward, flow into the opening 6a, and are discharged by the discharge pipe 6, so that a uniform crystal having a specified particle diameter or more can be obtained. Fig. 3 shows a third embodiment of the present invention. In this embodiment, the tip end portion of the inflow pipe 5 of the first embodiment is formed in a meandering manner in the crystallization tank 1 so that the inflow pipe 5 is formed. The opening 5a is formed upward, and a reverse cone-shaped water flow dispersion 13 312XP/invention specification (supplement)/93-11/93123420 1322803 5b is disposed above the opening 5a, and the front end portion of the outflow pipe 6 is made The lower end is bent and formed, and the end surface of the end portion is formed with an opening 6 b in a direction facing the inner side surface of the cracker 1 at the side surface of the front end portion. Thus, the aqueous solution of terephthalic acid is dispersed by the opening 5a > of the inflow pipe 5, and is dispersed by the reverse cone-shaped water dispersion 5b, and is dispersed and dissolved in the aqueous solution in the tank 1, so that the aeration of the airfoil against the airfoil can be prevented. The aqueous solution discharge efficiency of the wing 3 can be improved, and the initial dispersion of the inflowing energy can be obtained. Further, the opening of the outflow pipe 6 can raise the position of the particle grading solution which is crystallized in the peripheral portion of the inner bottom surface of the crystallization vessel 1 together with the position where it does not rise, so that the predetermined particle diameter can be absorbed by the negative pressure in the port 6b. Crystal particles. [Embodiment] The present invention will be described below based on examples, but the present invention is not limited to the examples. <Examples> (Example 1) The inventors specifically explained the above-described conventional production apparatus and the apparatus of the present embodiment 3 in the continuous operation. Adjusting a high-purity p-benzoquinone 2 slurry having a particle size distribution of 7 4 to 1 4 9 /zm, pressurizing the slurry in a dissolution tank and completing the aqueous terephthalic acid solution at 2 2 ° C Crystallization was carried out using three tandem lysis tanks of the same capacity. In this case, the inner diameter of the first crystallization tank is D, and the wing diameter R is 〇. 5 D when the wing diameter is R, and the shape of the wing is 312 中央 on the central portion side / invention specification (supplement) / 93-11 /93丨23420 The crystal inflow above the front of the crystal is closed, and the crystal is completely dissolved by the water of the first layer of the water that is used for the first step of the water, and the length of the lower direction 14 1322803 is 0.5F, and agitating blades composed of six fins whose length of the tip end portion of the blade is 0.15R in the vertical direction. The ratio of the ratio of the gap c between the lower end of the stirring blade and the bottom surface of the crystallization tank to the wing diameter R of the stirring blade is 0. 0 2 . Further, the number of rotations can be changed, and crystallization is performed at 0.2 and 0.7 kw / m3. On the other hand, in the second crystallization tank, a stirring blade having inclined blades of four blades was used, and the fixed stirring power was 0.7 kW/m3. The temperature of the first crystallization tank and the second crystallization tank is controlled so that the temperature of the first crystallization tank is 1 so that the total precipitation amount of terephthalic acid is about 70% by weight and about 99% by weight, respectively. The temperature of the second crystallization tank was 1,200 °C at 60 °C, and the temperature of the third crystallization tank was controlled at a temperature of 100 °C. The results of the physical property test on the terephthalic acid particles are listed. In Fig. 6, the difference between the embodiment and the comparative example is that the inclined blade blade having a wing diameter of 0.5 D is used in the comparative example, and all other operating conditions are the same as in the embodiment. Further, the particle size is a laser diffraction "scattering type particle size distribution measuring device. When the agitation power is 0. 2 k w / m3, the average particle size is 190. 7 // m, and the standard deviation is 61.1. Further, when the stirring power was 0.7 kw/m3, the average particle diameter was 134 " m, and the standard deviation was 46. 9, and it was found that terephthalic acid having a narrow particle size distribution was obtained. (Industrial Applicability) According to the present invention, it is possible to efficiently obtain a crystal of a picolinic acid and further have an effect of controlling the crystal grain size. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a cross-sectional view showing a first embodiment of the present invention. Fig. 2 is a cross-sectional view showing an important part of a second embodiment of the present invention. 15 312XP/Invention Manual (Supplement)/93-11/93123420 1322803 Fig. 3 is a cross-sectional view showing an important part of a third embodiment of the present invention. Fig. 4 is a cross-sectional view showing an example of a conventional manufacturing apparatus. Fig. 5 is a cross-sectional view showing another example of a conventional manufacturing apparatus. Fig. 6 is a graph showing the relationship between the stirring power in the crystallization tank of the present invention and the particle size distribution of terephthalic acid in the conventional production apparatus. [Description of main components] 1 Crystallization tank 2 Rotary shaft 3 Stirring wing 3a Wing body 4 Obstruction plate 5 Inflow pipe 5a Opening D 5b Water flow 6 Ejecting pipe 6 a , 6b Opening σ a Stirring tank b Rotary shaft c Stirring wing d Obstruction plate e crystallization tank f rotation axis g stirring wing h collision plate 16 312XP / invention manual (supplement) / 93-11/93123420