200407291 Ο) 玖、發明說明 【發明所屬之技術領域】 本發明有關一種製備雙酚A[252-雙（4 一羥苯基）丙 烷]的方法，且更特而言之有關一種在製備方法中分離雙 雙酚A與酚之加合物的方法。 【先前技術】 一般知道雙酚A爲一種作爲製備工程學塑膠例如聚 碳酸酯樹脂及聚丙烯酸樹脂或環氧樹脂之原料的重要化合 物。近幾年來，對雙酚A的需要越來越增加。 雙酚A已藉由在酸催化劑存在下（任意地和共催化 劑例如硫化合物）縮合過量酚與丙酮製得。 爲了從反應混合物分離如此製得之雙酚A，在直接從 反應混合物分離粗結晶形式之雙酚A的方法，或首先從 反應混合物除去丙酮、水及其他且然後濃縮和冷卻所得之 液體混合物以從其沈澱和分離雙酚 A與酚之加合物的方 法爲已知的。 在其中粗結晶形式之雙酚A直接地從反應混合物分 離之前方法中，因爲雙酚A爲精結晶形式，所以重複的 洗滌步驟是必須的和，因此，該方法具有缺點例如在方法 中的大量損失。 爲了這個原因，目前，已經優先使用其中雙酣A與 酚之加合物被結晶及分離的後方法。在該類方法中’雙酚 A與酚之加合物被結晶，及藉由使用過濾器或離心分離器 -5- (2) (2)200407291 之已知固液分離方法從母液分離所得的結晶（例如，參照 曰本專利申請案公開號昭和5 7 — 7 7 6 3 7、平5 — 3 3 1 0 8 8、 昭和 63 — 275539 及平 6 — 306002)。 這些固液分離方法之中，在使用過濾器的分離方法之 情況中’可使吸入式皮帶過濾器、盤式過濾器、鼓式過濾 器或類似物（例如，參照日本專利申請案公開號平7 -25 79 8，第3頁，[00 1 1]段）。在上述使用過濾器之分離 方法中，需要增加欲過濾之結晶的大小且藉此減少其表面 積以便防止由於過濾器的網目大小之損失及提高所得產物 的純度（例如，參照日本專利申請案公開號平5 — 3 3 1 0 8 8 )° 在該藉由過濾之分離方法中，所得產物具有大液體含 量’且其不易充份地除去包含在結晶間之母液等。除此之 外’具有母液堅固地倂入結晶中之危險。當減少結晶大小 以防止母液倂入其中時，允許母液平滑地通過結晶層是困 難的’或易於發生過濾器材料的阻塞，造成處理效率之顯 著惡化。 另一方面，使用離心分離器的方法較佳減少包含在結 晶之間的液體量和獲得更乾燥狀態之加合物。然而，由於 施用至其上之離心負載，結晶易於被壓碎，所以母液、淸 潔溶液等之替換的效率被惡化，如與該等過濾方法比較。 因此’當欲處理大量產物時，一般，不可避免地需要重複 使用多數裝置之淸潔步驟以便提高產物的純度，其造成增 加所用裝置之數目、延長操作時間和因此爲不經濟之方法 -6 - (3) (3)200407291 同時，爲了獲得具有優良色調和高純度之高品質雙酉分 A，已知有結晶及分離雙酌A與酚之加合物，然後在低氧 大氣下熔化經結晶之加合物以將其脫酚的方法（例如，參 照日本專利申請案公開號平5— 32577、平5— 39238、平 6— 25044 和平 6— 25045)。 【發明內容】 鑑於上述問題，本發明之目的爲提供一種藉由在從反 應混合物取出雙酚A時從反應母液高效率回收雙酚a與 酣之高純度加合物之製備雙酣A的方法。 爲了解決上述製造備雙酚A的習知方法之問題，廣 泛硏究的結果，本發明人已發現當吸入式水平無端皮帶過 濾器使用於固液分離，和在特殊條件下操作同時引入經加 熱之惰性氣體流以便結晶及分離雙酚A與酚之加合物時， 其可能以穩定和連續的方式有效回收具有高純度之雙酚A 與酚之加合物。本發明以此發現爲基礎而已完成。 因此，本發明提供下列製備雙酚A的方法： 1 · 一種製備雙酚A的方法，其係藉由從在酸催化劑 存在下反應酚與丙酮而得之雙酚A的酚溶液結晶雙酚A 與酚之加合物，將所得漿料分離成固體成分和液體成分， 及然後從固體成分除去酚，該方法包含： (1 )在減壓下於經加熱之惰性氣體流中將包含結晶 態之雙酚A與酚之加合物的漿料溶液引進水平無端皮帶 (4) (4)200407291 過濾器上，以在其上形成雙酚A與酚的經結晶之加合物 層； (2 )包含在加合物層中的母液通過過濾器分離以減 少加合物層中的液體含量到3 0重量％或更低和 (3 )藉由其配衡（tare )分離加合物和過濾器層。 2 _根據上述觀點1的方法，其中經加熱之惰性氣體 爲一種具有8 0 °C或更低的溫度和5 5 0 0 0 p p m或更低的氧濃 度之氮氣。 3 ·根據上述觀點1的方法，其中控制真空度和水平 無端皮帶過濾器的皮帶速度以減少加合物層中的液體含量 到3 0重量％或更低。 4 ·根據上述觀點1的方法，其中在藉由其配衡從過 濾器分離加合物層之前以淸潔溶液洗滌加合物層。 【實施方式】 進行本發明之最佳模態 在根據本發明之製備雙酚A的方法中，雙酚A係經 由（A )反應酚與丙酮的步驟；（B )除去副產之水和包 括未反應原料之低沸點物質的步驟，（C )濃縮雙酚A的 步驟；（D )結晶和固液分離步驟，（D ')雙酚的酚加合 物之溶解、結晶和固液分離的步驟；（E )熱熔化步驟； (F )雙酚A的脫酚步驟；和（G )粒化步驟。 在本發明中，使用水平無端皮帶過濾器，且該皮帶過 濾器在特殊條件下操作完成固液分離步驟（D )及（D 〇 -8 - (5) (5)200407291 如上所述，習知一種方法，其中雙酚A與酚之加合 物被結晶及分離，在低氧大氣下熔化，然後進行脫酌以獲 得具有優良色調和高純度之高品質雙酚A。 然而，即使經結晶及分離的雙酚A與酚之加合物在 低氧大氣下熔化及然後進行脫酚，其不可能防止雙酚A 與酚之加合物被包含在其中的氧不利地影響。 相反地’根據本發明，水平無端皮帶過濾器使用於固 液分離步驟（D )和（D 〇中，和在減壓下作爲低氧大氣 的經加熱之惰性氣體引戊包含結晶態的雙酚A與酚之加 合物的漿料溶液內。因此，因爲包含在加合物中的氧被有 效地除去，所以可能獲得具有仍高品質的雙酚A。 接著’根據本發明之製備雙酚A的方法之個別步驟 解釋於下。 (A )反應步驟 在反應步驟（A )中，在酸催化劑存在下過量酚與丙 酮縮合以產生雙酚A。作爲酸催化劑，可使用酸類離子交 換樹脂。酸類離子交換樹脂的例子包括（但不特別限制於 )習知用於製備雙酚A的催化劑和鑑於其催化活性，較 佳爲磺酸類陽離子交換樹脂。 且，該等磺酸類陽離子交換樹脂不特別地限制，只要 他們是含磺酸基的強酸陽離子交換樹脂。磺酸類陽離子交 換樹脂的例子包括經磺酸化之苯乙烯一二乙烯基苯共聚物 -9- (6) (6)200407291 ，經磺酸化之交聯苯乙烯聚合物，酚一甲醛一磺酸樹脂， 本-甲醒-擴酸樹脂或類似物。這些磺酸類陽離子交換樹 脂可單獨地使用或以其任何二或多個的組合使用。 在本發明的方法中，上述酸類離子交換樹脂通常可與 作爲共催化劑硫醇組合使用。該等硫醇爲其分子中包含自 由S Η基的化合物。作爲硫醇，可使用烷基硫醇，和包含 一或多個選自羧基、胺基、羥基等的取代基之經取代之烷 基硫醇，例如，锍基羧酸、胺基烷硫醇、锍基醇或相似物 。硫醇特殊的例子包括烷硫醇例如甲硫醇、乙硫醇、正丁 硫醇和正辛硫醇，硫代羧酸例如毓基醋酸，/3 -锍基丙酸 ’胺基院硫醇例如2 -胺基乙硫醇，疏基醇例如|荒基乙醇 ，或相似物。這些硫醇類中，鑑於作爲共催化劑之效果， 烷基硫醇爲特佳。這些硫醇可單獨地使用或以其任何二或 多個的組合使用。 這些硫醇可固定於上述酸類離子交換樹脂上以作用爲 共催化劑。 所用的硫醇之量通常從0 ·1到2 0莫耳％和較佳1到 1 〇莫耳％之範圍選擇，以作爲原料的丙酮爲基準。 所使用的酚和丙酮的量之間的比不特別地限制’但鑑 於有助於所得雙酚之純化作用和經濟方法’希望未反應丙 酮的量減到最少。因此’使用相對於其化學計量爲過量的 酚是有利，通常在每莫耳丙酮3到3 0莫耳和較佳5到1 5 莫耳之量。且，在製備雙酌Α中’通常所使用之反應溶 劑不重要，除了在其中反應在低溫進行之情形之外’因爲 -10- (7) (7)200407291 由於反應溶液的太高黏度或其固化之發生而反應的操作困 難。 雖然在酚和丙酮之間的縮合反應可藉由任何批次和連 續的方法完成，但可有利地使用固定床式連續反應方法， 其中酚和丙酮以及硫醇（在硫醇不固定在酸類離子交換樹 脂上之情況中）不斷地供應到裝滿酸類離子交換樹脂之反 應塔，然後彼此反應。在此情況中，可使用任何單一反應 塔或二或多個串連反應塔。從工業上的觀點，採用一種使 用二或多個裝滿酸類離子交換樹脂之反應塔的固定床式多 階段連續反應方法爲特佳。 固定床式連續反應方法的反應條件解釋於下。 首先，丙酮對酚的莫耳比選自通常1 / 3 0到1 / 3和 較佳1 / 1 5到1 / 5之範圍。當丙酮對酚的莫耳比小於1 / 3 0時，反應率容易變成太慢。當丙酮對酚的莫耳比超 過1 / 3時，容易產生大量雜質，及對雙酚A的選擇性容 易被惡化。另一方面，在硫醇不固定於酸一類型離子交換 樹脂的情形中，硫醇對丙酮的莫耳比選自通常〇. 1 / 1 00 到20/ 1 00和較佳1/ 100到10/ 100之範圍。當硫醇對 丙酮的莫耳比小於0.1/ 1〇〇時，充份呈現至雙酚A之反 應率和選擇性之趨勢。甚至硫醇對丙酮的莫耳比超過20 / 1 〇 〇，雖然使用該大量的硫醇但沒有認出效果的進一步 改進。 且，縮合反應溫度可選自通常40到150°C和較佳60 到U〇°C之範圍。當反應溫度低於40 °C時，反應率變成太 -11 - (8) (8)200407291 慢，且反應溶液的黏度變成極端地高，所以有該反應溶液 被固化的趨向。當反應溫度高於1 5 0 t時，傾向於控制反 應是困難的，和再者至雙酚A ( p，p' -異構物）的選擇性 進一步被惡化。除此之外，作爲催化劑之酸類離子交換樹 脂傾向於分解或品質惡化。進一步地，原料混合物之液體 每小時空間速度（LHSV )也可選自通常0.2到30小時一 1 和較佳〇. 5到1 0小時—1之範圍。 (B )除去低沸點物質的步驟 在除去低沸點物質的步驟中，包含雙酚A之液態反 應混合物，其在前述反應步驟（A )中獲得，被純化成實 質上沒有作爲催化劑的酸類離子交換樹脂包含在其中之情 況。更特而言之，在批次反應方法中，催化劑藉_過濾除 去。且，在固定床式連續反應方法中，低沸點物質在步驟 期間直接從反應混合物移除。 在此步驟（B )中，一般，低沸點物質例如未反應之 丙酮，副產之水和烷基硫醇在減壓下使用蒸餾塔蒸餾除去 〇 在減壓下的蒸餾通常可在6.5到80 kPa的壓力下於 7 0到1 8 (TC的溫度進行。在該蒸餾中，未反應酚進行共沸 蒸餾，及一部份的未反應酚和上述來自反應系統之低沸點 物質從蒸餾塔頂端一起蒸餾掉。上述蒸餾步驟較佳使用具 有1 9(TC或較低的加熱溫度之加熱來源以便避免所得雙酚 A的熱分解。除此之外，作爲反應裝置，通常可使用該等 -12- (9) 200407291 由SUS304、 SUS316或SUS316L製造的裝置。 (C )濃縮步驟 藉由從包含雙酚A、酚或相似物之反應混合物除 沸點物質而得之塔底液。塔底液在減壓下進行蒸餾以 蒸餾掉酚，藉此濃縮雙酚A。濃縮條件不特別地限制 濃縮步驟通常可在約1 00到1 70°C溫度、5到70 kP a 力下進行。當濃縮溫度低於1 00 °C更時，濃縮步驟必 下高真空條件下進行。當濃縮溫度高於1 7 0 °C時，除 來結晶步驟中的過量熱是不想要的需要。雙酚A在 溶液中的濃度較佳爲2 0到5 0重量％和更佳2 0到4 0 %。當雙酚A的濃度小於2 0重量％時，雙酚a的回 降低時。當雙酚A的濃度超過5 0重量％時，不易輸 晶之後獲得的漿料。 (D )結晶和固液分離步驟 在結晶和固液分離步驟（D )中，將雙酚a與酚 :1加合物（以下有時稱爲 ''酚加合物〃）從在上述 步驟（C )所得之濃縮溶液結晶及分離。 在這個步驟中，首先，濃縮溶液冷卻到約4 0到 之溫度以結晶酚加合物且形成其漿料。濃縮溶液的冷 使用外部熱交換器，或藉由真空冷卻結晶方法進行， 濃縮溶液和水混合，然後在減壓下使用水的汽化之潛 卻。在真空冷卻結晶方法中’在加入約3到2 0重量 去低 從其 ，且 的壓 須在 去後 濃縮 重量 收率 送結 的1 濃縮 7 0°C 卻可 其中 熱冷 %之 -13- (10) 200407291 量的水後，濃縮溶液通常在4到1 6 kP a的壓力下5 7 0 °C的溫度進行結晶處理。當加入的水里小於3重 ，熱移除能力是不夠的。當加入的水量超過2 〇重 ，雙酚 A的溶解損失變成不想要的大。在該結晶 ，當結晶溫度低於40 °C時，結晶溶液容易增加黏 化。當結晶溫度超過7 0 °C時，雙酚A的溶解損失 想要的大。 在本發明的方法中，包含如此結晶之酣的加合 料然後在經加熱之惰性氣體流、減壓下引進水平無 過濾器（以下有時只稱爲'、皮帶過濾器）上以在 濾器上形成由經結晶的雙酚A與酚之加合物組成的 水平無端皮帶過濾器包括多孔無端皮帶運送裝 撐在其上之過濾布器，且在真空箱上移動。漿料供 帶過濾器的一端以過濾出濾餅及洗滌濾餅。藉由其 皮帶過濾器分離所得濾餅。作爲水平無端皮帶過濾 濾器布，可使用以聚丙烯、聚酯、耐綸、聚四氟乙 布、麻織物等製成的多孔片。 因爲其允許在沒有對其應用大地心引力負載下 濾，所以使用水平無端皮帶過濾器是有利的。 在此情況中，結晶態的雙酚 A與酚之加合物 有0.05至1 mm之平均粒子大小。當平均粒子大 〇 . 0 5 m m時，分離酚加合物的結晶和母液彼此變爲 導致過濾物質之阻塞的發生和處理效率之惡化。當 子大小超過1 m時，母液易於堅固地合倂在結晶寸 之40到 量％時 量％時 處理中 度或固 變成不 物之漿 端皮帶 皮帶過 層。 置及支 應到皮 配衡從 器的過 稀、棉 連續過 較佳具 小小於 困難， 平均粒 -14- (11) (11)200407291 作爲惰性氣體，通常可使用具有5.000 ppm或更低和 較佳3,00 0 ppm或更低的氧濃度之氮氣。 藉由通過皮帶過濾器分離包含在加合物層的母液，加 合物層的液體含量減少到3 0重量％或更低和較佳25重量 %或更低。一旦從皮帶過濾器分離，爲了允許於濾餅形式 之加合物層因其配衡自然地掉下，需要減少在加合物層的 液體含量到3 0重量％或更低。當沈積在皮帶過濾器上的 加合物中之液體含量降低，在後來步驟中所需要之負載變 得較小。 當上述過濾.在減壓下進行時，從酚加合物的結晶分離 母液及減少在加合物層中之液體含量變爲可能。 然而，如果真空度太強，酚加合物的結晶傾向於有時 壓碎成太細的粉末。該太細的粉末容易促進例如過濾布之 阻塞的麻煩。真空度較佳爲6 0到9 5 kP a。 除此之外，因爲加合物層中的液體含量受皮帶過濾器 之運轉速度（皮帶速度）影響，所以藉由適當地控制真空 度和水平無端皮帶過濾器的皮帶速度，加合物層中的液體 含量可減少到3 0重量％或更低。 加合物層的厚度不特別地限制，只要沈積在皮帶過濾 器上之酚加合物層具有3 0重量％或更低的液體含量。然 而，太大厚度的加合物層導致其每單位面積重量增加，所 以應用到裝置的負載變成不利地高。 同時，在藉由其配衡從水平無端皮帶過濾器分離雙酚 A與酚之加合物層之前，加合物層較佳藉由將淸潔溶液噴 -15- (12) (12)200407291 霧至其上洗滌以便可能地除去包含在加合物層的雜質和痕 量之酸催化劑。用來洗滌處理的淸潔溶液之例子包括酚、 水、水和酚的混合溶液，或藉由溶解雙酚 A在這些溶液 中而得的溶液。 加合物層的厚度和真空吸入時間可藉由改變皮帶速度 來控制。當皮帶加速減少，沈積在皮帶過濾器上之酚加合 物的厚度變得較大，但其可能允許加合物層暴露在減壓下 較長的時間。 爲了在過濾時維持包含經結晶之酚加合物的漿料，必 需調節其溫度到8 0 °C或更低。除此之外，因爲母液或淸 潔溶液傾向於固化，所以保持包括皮帶過濾器的周圍大氣 於3 0到8 0 °C和較佳3 5到5 0 °C的溫度是重要的。 如此分離的母液可直接地（也就是，完全地）或部份 地循環到反應器。或者，母液可完全地或部份地異構化， 然後循環作爲欲結晶的原料。200407291 〇). Description of the invention [Technical field to which the invention belongs] The present invention relates to a method for preparing bisphenol A [252-bis (4-hydroxyphenyl) propane], and more particularly to a method in the preparation method Method for separating adduct of bisbisphenol A and phenol. [Prior art] Bisphenol A is generally known as an important compound as a raw material for preparing engineering plastics such as polycarbonate resins and polyacrylic resins or epoxy resins. In recent years, the demand for bisphenol A has been increasing. Bisphenol A has been prepared by condensing excess phenol and acetone in the presence of an acid catalyst (optionally with a co-catalyst such as a sulfur compound). In order to separate the bisphenol A thus obtained from the reaction mixture, in a method of directly separating the bisphenol A in crude crystalline form from the reaction mixture, or first removing acetone, water, and other liquid mixtures from the reaction mixture and then concentrating and cooling the resulting liquid mixture, Methods for precipitating and separating adducts of bisphenol A and phenol therefrom are known. In the method in which the crude crystalline form of bisphenol A is directly separated from the reaction mixture, since bisphenol A is in a finely crystalline form, repeated washing steps are necessary and, therefore, the method has disadvantages such as a large amount in the method loss. For this reason, post-processes in which the adduct of difluorene A and phenol is crystallized and separated have been preferentially used. In this type of method, the adduct of bisphenol A and phenol is crystallized, and the obtained from the mother liquid is separated by a known solid-liquid separation method using a filter or a centrifugal separator-5- (2) (2) 200407291. Crystals (for example, refer to Japanese Patent Application Publication No. Showa 5 7-7 7 6 3 7, Hei 5-3 3 1 0 8 8, Showa 63-275539 and Hei 6-306002). Among these solid-liquid separation methods, in the case of a separation method using a filter, 'a suction belt filter, a disc filter, a drum filter, or the like can be made (for example, refer to Japanese Patent Application Publication No. Hei. 7 -25 79 8, page 3, paragraph [00 1 1]). In the above-mentioned separation method using a filter, it is necessary to increase the size of crystals to be filtered and thereby reduce its surface area in order to prevent loss due to the mesh size of the filter and improve the purity of the obtained product (for example, refer to Japanese Patent Application Publication No. Hei 5 — 3 3 1 0 8 8) ° In this separation method by filtration, the obtained product has a large liquid content and it is not easy to sufficiently remove the mother liquid and the like contained in the crystal spaces. In addition to this, there is a danger that the mother liquor is firmly incorporated into the crystal. When the crystal size is reduced to prevent the mother liquor from being entrapped therein, it is difficult to allow the mother liquor to smoothly pass through the crystal layer 'or the clogging of the filter material is liable to occur, resulting in a significant deterioration in processing efficiency. On the other hand, the method using a centrifugal separator preferably reduces the amount of liquid contained between crystals and obtains an adduct in a drier state. However, due to the centrifugal load applied to it, the crystals are easily crushed, so the replacement efficiency of mother liquor, cleaning solution, etc. is deteriorated, as compared with these filtration methods. Therefore, 'when a large amount of product is to be processed, in general, it is unavoidable to repeat the cleaning steps of most devices in order to improve the purity of the product, which results in an increase in the number of devices used, a prolonged operation time, and therefore an uneconomical method. (3) (3) 200407291 At the same time, in order to obtain high-quality bisphenol A with excellent color tone and high purity, it is known to crystallize and separate the adduct of bisphenol A and phenol, and then melt it in a low-oxygen atmosphere to crystallize A method for dephenolizing the adduct thereof (for example, refer to Japanese Patent Application Publication Nos. Hei 5-32577, Hei 5-39238, Hei 6-25044 and Hei 6-25045). [Summary of the Invention] In view of the above problems, an object of the present invention is to provide a method for preparing bisfluorene A by efficiently recovering a high-purity adduct of bisphenol a and fluorene from a reaction mother liquid when bisphenol A is taken out from a reaction mixture. . In order to solve the problems of the above-mentioned conventional method for preparing bisphenol A, as a result of extensive research, the present inventors have discovered that when a suction horizontal endless belt filter is used for solid-liquid separation, and operated under special conditions, the heated When the inert gas stream is used to crystallize and separate the adduct of bisphenol A and phenol, it is possible to efficiently recover the adduct of bisphenol A and phenol with high purity in a stable and continuous manner. The present invention has been completed based on this finding. Therefore, the present invention provides the following method for preparing bisphenol A: 1. A method for preparing bisphenol A, which crystallizes bisphenol A from a phenol solution of bisphenol A obtained by reacting phenol with acetone in the presence of an acid catalyst Adduct with phenol, separating the resulting slurry into solid and liquid components, and then removing phenol from the solid component, the method comprising: (1) crystalline state will be contained in a heated inert gas stream under reduced pressure The slurry solution of the adduct of bisphenol A and phenol is introduced into a horizontal endless belt (4) (4) 200407291 filter to form a crystallized adduct layer of bisphenol A and phenol thereon; (2 ) The mother liquor contained in the adduct layer is separated through a filter to reduce the liquid content in the adduct layer to 30% by weight or less and (3) the adduct is separated and filtered by its balance (tare)器 层。 Device layer. 2 _ The method according to the above point 1, wherein the heated inert gas is a nitrogen gas having a temperature of 80 ° C or lower and an oxygen concentration of 5500 p pm or lower. 3. The method according to the above point 1, wherein the belt speed of the endless belt filter is controlled to reduce the liquid content in the adduct layer to 30% by weight or less. 4. The method according to the above point 1, wherein the adduct layer is washed with a cleaning solution before the adduct layer is separated from the filter by its balance. [Embodiment] The best mode for carrying out the present invention In the method for preparing bisphenol A according to the present invention, bisphenol A is via (A) a step of reacting phenol with acetone; (B) removing by-product water and including Steps of low-boiling substances of unreacted raw materials, (C) step of concentrating bisphenol A; (D) crystallization and solid-liquid separation step, (D ') dissolution, crystallization and solid-liquid separation of phenol adduct of bisphenol Steps; (E) a thermal melting step; (F) a phenol removal step of bisphenol A; and (G) a granulation step. In the present invention, a horizontal endless belt filter is used, and the belt filter is operated under special conditions to complete the solid-liquid separation steps (D) and (D 〇-8-(5) (5) 200407291) A method in which an adduct of bisphenol A and phenol is crystallized and separated, melted in a low-oxygen atmosphere, and then discarded to obtain high-quality bisphenol A with excellent color tone and high purity. However, even after crystallization and The isolated adduct of bisphenol A and phenol is melted in a low-oxygen atmosphere and then subjected to dephenolization, which is impossible to prevent the adduct of bisphenol A and phenol from being adversely affected by the oxygen contained therein. In the present invention, a horizontal endless belt filter is used in the solid-liquid separation steps (D) and (D0), and a heated inert gas, which is a low-oxygen atmosphere under reduced pressure, contains crystalline bisphenol A and phenol. In the slurry solution of the adduct. Therefore, because the oxygen contained in the adduct is effectively removed, it is possible to obtain bisphenol A with still high quality. Then, 'the method of preparing bisphenol A according to the present invention The individual steps are explained below. (A) In the reaction step (A), excess phenol is condensed with acetone in the presence of an acid catalyst to produce bisphenol A. As the acid catalyst, an acidic ion exchange resin can be used. Examples of the acidic ion exchange resin include (but are not particularly limited to) ) Conventional catalysts for the preparation of bisphenol A and in view of their catalytic activity, sulfonic acid cation exchange resins are preferred. Moreover, the sulfonic acid cation exchange resins are not particularly limited as long as they are strong acid cations containing a sulfonic acid group. Examples of sulfonic acid cation exchange resins include sulfonated styrene-divinylbenzene copolymer-9- (6) (6) 200407291, sulfonated crosslinked styrene polymer, phenol-formaldehyde- Sulfonic acid resins, present-formaldehyde-acid-expansion resins or the like. These sulfonic acid cation exchange resins can be used alone or in combination of any two or more of them. In the method of the present invention, the above acidic ion exchange resins Usually it can be used in combination with thiol as a co-catalyst. These thiols are compounds containing a free S fluorenyl group in the molecule. As thiols, alkylthios can be used. And substituted alkyl mercaptans containing one or more substituents selected from carboxyl, amine, hydroxyl, etc., such as fluorenyl carboxylic acid, amino alkyl mercaptan, fluorenyl alcohol or the like. Thiols Specific examples include alkyl mercaptans such as methyl mercaptan, ethyl mercaptan, n-butane mercaptan, and n-octyl mercaptan, thiocarboxylic acids such as acetic acid, and / 3-fluorenylpropionic acid 'amines such as 2- Amine ethyl mercaptan, thiol alcohol such as | ethanol, or the like. Among these thiols, alkyl thiols are particularly preferred in view of their effect as co-catalysts. These thiols can be used alone or in combination. Any two or more of them can be used in combination. These thiols can be immobilized on the above acidic ion exchange resins to act as co-catalysts. The amount of thiols used is usually from 0.1 to 20 mole% and preferably from 1 to 1. The range of mol% is selected based on acetone as a raw material. The ratio between the amount of phenol and acetone used is not particularly limited ', but it is desirable to minimize the amount of unreacted acetone in view of its contribution to the purification and economic method of the obtained bisphenol. It is therefore advantageous to use phenol in excess relative to its stoichiometry, usually in an amount of 3 to 30 moles and preferably 5 to 15 moles per mole of acetone. And, in the preparation of Shuangcai A, the reaction solvent usually used is not important, except for the case where the reaction is carried out at a low temperature, because -10- (7) (7) 200407291 due to the too high viscosity of the reaction solution or its The operation of curing occurs and the operation is difficult. Although the condensation reaction between phenol and acetone can be accomplished by any batch and continuous method, a fixed-bed continuous reaction method can be advantageously used in which phenol and acetone and thiols (where thiols are not fixed to acid ions) In the case of an exchange resin, it is continuously supplied to a reaction tower filled with an acidic ion exchange resin, and then reacts with each other. In this case, any single reaction column or two or more series reaction columns may be used. From an industrial point of view, a fixed-bed multi-stage continuous reaction method using two or more reaction towers filled with an acid ion exchange resin is particularly preferred. The reaction conditions of the fixed-bed continuous reaction method are explained below. First, the molar ratio of acetone to phenol is selected from the range of usually 1/30 to 1/3 and preferably 1/15 to 1/5. When the molar ratio of acetone to phenol is less than 1/30, the reaction rate tends to become too slow. When the molar ratio of acetone to phenol exceeds 1/3, a large amount of impurities are easily generated, and the selectivity to bisphenol A is easily deteriorated. On the other hand, in the case where the thiol is not fixed to the acid-type ion exchange resin, the molar ratio of the thiol to acetone is selected from generally 0.1 / 1 00 to 20/1 00 and preferably 1/100 to 10 / 100 range. When the molar ratio of thiol to acetone is less than 0.1 / 100, the reaction rate and selectivity of bisphenol A are fully exhibited. Even when the molar ratio of thiol to acetone exceeds 20/1, although no further improvement of the effect was recognized although the large amount of thiol was used. And, the condensation reaction temperature may be selected from the range of usually 40 to 150 ° C and preferably 60 to 60 ° C. When the reaction temperature is lower than 40 ° C, the reaction rate becomes too low. (8) (8) 200407291 is slow, and the viscosity of the reaction solution becomes extremely high, so the reaction solution tends to be cured. When the reaction temperature is higher than 150 t, it tends to be difficult to control the reaction, and further, the selectivity to bisphenol A (p, p'-isomer) is further deteriorated. In addition, acid ion-exchange resins used as catalysts tend to decompose or deteriorate in quality. Further, the liquid hourly space velocity (LHSV) of the raw material mixture may also be selected from the range of usually 0.2 to 30 hours-1 and preferably 0.5 to 10 hours-1. (B) Step of removing low-boiling substances In the step of removing low-boiling substances, a liquid reaction mixture containing bisphenol A, which was obtained in the aforementioned reaction step (A), was purified to have substantially no acid ion exchange as a catalyst When resin is included. More specifically, in a batch reaction process, the catalyst is removed by filtration. And, in the fixed-bed continuous reaction method, low-boiling substances are directly removed from the reaction mixture during the step. In this step (B), generally, low-boiling substances such as unreacted acetone, by-product water and alkyl mercaptan are distilled off under reduced pressure using a distillation column. Distillation under reduced pressure can usually be 6.5 to 80 At a pressure of kPa at a temperature of 70 to 18 ° C. In this distillation, the unreacted phenol is subjected to azeotropic distillation, and a part of the unreacted phenol and the above-mentioned low boiling point substances from the reaction system are from the top of the distillation column. Distill off together. The above distillation step preferably uses a heating source with 19 ° C or lower heating temperature in order to avoid thermal decomposition of the obtained bisphenol A. In addition, as a reaction device, such -12 can usually be used -(9) 200407291 A device made of SUS304, SUS316 or SUS316L. (C) Concentration step A bottom liquid obtained by removing boiling point substances from a reaction mixture containing bisphenol A, phenol or the like. The bottom liquid is decreasing Distillation is performed under reduced pressure to distill off phenol, thereby concentrating bisphenol A. The concentration conditions are not particularly limited. The concentration step can usually be performed at a temperature of about 100 to 1 70 ° C and a force of 5 to 70 kPa. When the concentration temperature is low At 100 ° C, the concentration step must be performed. It is carried out under vacuum. When the concentration temperature is higher than 170 ° C, it is not necessary to remove excess heat in the crystallization step. The concentration of bisphenol A in the solution is preferably 20 to 50% by weight and More preferably 20 to 40%. When the concentration of bisphenol A is less than 20% by weight, the return of bisphenol a decreases. When the concentration of bisphenol A exceeds 50% by weight, it is difficult to obtain a slurry obtained after crystal infusion. (D) Crystallization and solid-liquid separation step In the crystallization and solid-liquid separation step (D), bisphenol a and phenol: 1 adduct (hereinafter sometimes referred to as `` phenol adduct 〃 '') The concentrated solution obtained in the above step (C) is crystallized and separated. In this step, first, the concentrated solution is cooled to a temperature of about 40 to to crystallize the phenol adduct and form a slurry thereof. The concentrated solution is cooled using external heat exchange Device, or by vacuum cooling crystallization method, the concentrated solution is mixed with water, and then the vaporization potential of water is used under reduced pressure. In the vacuum cooling crystallization method, 'about 3 to 20 weight is added to reduce it, And the pressure must be concentrated after the weight yield is sent to the concentration of 1 at 70 ° C, but it can be heated After cooling the amount of -13- (10) 200407291, the concentrated solution is usually crystallized at a temperature of 5 7 0 ° C under a pressure of 4 to 16 kPa. When the added water is less than 3 weights, heat transfer The removal ability is not enough. When the amount of water added exceeds 20 weight, the dissolution loss of bisphenol A becomes undesirably large. In this crystallization, when the crystallization temperature is lower than 40 ° C, the crystallization solution easily increases viscosity. When crystallization When the temperature exceeds 70 ° C, the dissolution loss of bisphenol A is desirably large. In the method of the present invention, the admixture containing the thus-crystallized gadolinium is then introduced at a reduced pressure under a heated inert gas stream under reduced pressure. A horizontal endless belt filter consisting of an adduct of crystallized bisphenol A and phenol is formed on a filter (hereinafter sometimes referred to as a 'belt filter'). The endless belt filter includes a porous endless belt carrier. The filter cloth on the top, and move on the vacuum box. The slurry is supplied to one end with a filter to filter out the cake and wash the cake. The resulting cake was separated by its belt filter. As the horizontal endless belt filter cloth, a porous sheet made of polypropylene, polyester, nylon, polytetrafluoroethylene, hemp fabric, or the like can be used. Because it allows filtration without applying a gravitational load thereto, it is advantageous to use a horizontal endless belt filter. In this case, the crystalline adduct of bisphenol A and phenol has an average particle size of 0.05 to 1 mm. When the average particle size is 0.05 mm, the crystals and mother liquor of the separated phenol adducts become each other, leading to the occurrence of clogging of the filter material and deterioration of the processing efficiency. When the child size exceeds 1 m, the mother liquor is easy to combine sturdily. When the crystal size is 40% to 5% by volume, the medium or solid slurry will be processed. Placement and support should be too thin for the leather balancer, continuous cotton is better with less than difficulty, average grain -14- (11) (11) 200407291 As an inert gas, usually with 5.000 ppm or lower and more Best nitrogen with an oxygen concentration of 3,000 ppm or less. By separating the mother liquid contained in the adduct layer through a belt filter, the liquid content of the adduct layer is reduced to 30% by weight or less and preferably 25% by weight or less. Once separated from the belt filter, in order to allow the adduct layer in the form of a cake to fall off naturally due to its balance, it is necessary to reduce the liquid content in the adduct layer to 30% by weight or less. As the liquid content of the adduct deposited on the belt filter decreases, the load required in the subsequent steps becomes smaller. When the above filtration is performed under reduced pressure, it becomes possible to separate the mother liquor from the crystals of the phenol adduct and reduce the liquid content in the adduct layer. However, if the degree of vacuum is too strong, the crystallization of the phenol adduct tends to sometimes be crushed into a too fine powder. This too fine powder easily contributes to troubles such as clogging of filter cloth. The degree of vacuum is preferably 60 to 95 kPa. In addition, because the liquid content in the adduct layer is affected by the running speed (belt speed) of the belt filter, by properly controlling the vacuum and the belt speed of the horizontal endless belt filter, the adduct layer The liquid content can be reduced to 30% by weight or less. The thickness of the adduct layer is not particularly limited as long as the phenol adduct layer deposited on the belt filter has a liquid content of 30% by weight or less. However, an adduct layer of too large thickness causes its weight per unit area to increase, so the load applied to the device becomes disadvantageously high. Meanwhile, before the adduct layer of bisphenol A and phenol is separated from the horizontal endless belt filter by its balance, the adduct layer is preferably sprayed with a cleaning solution -15- (12) (12) 200407291 It was mist-washed thereon to possibly remove impurities and trace amounts of the acid catalyst contained in the adduct layer. Examples of the cleaning solution used for the washing treatment include phenol, water, a mixed solution of water and phenol, or a solution obtained by dissolving bisphenol A in these solutions. The thickness of the adduct layer and the vacuum suction time can be controlled by changing the belt speed. As the belt acceleration decreases, the thickness of the phenol adduct deposited on the belt filter becomes larger, but it may allow the adduct layer to be exposed to reduced pressure for a longer period of time. In order to maintain a slurry containing the crystallized phenol adduct during filtration, it is necessary to adjust its temperature to 80 ° C or lower. Besides, because the mother liquor or cleaning solution tends to solidify, it is important to keep the surrounding atmosphere including the belt filter at a temperature of 30 to 80 ° C and preferably 35 to 50 ° C. The mother liquor thus separated can be recycled directly (i.e., completely) or partially to the reactor. Alternatively, the mother liquor may be fully or partially isomerized and then recycled as a raw material to be crystallized.
爲了獲得高純度產物，重複結晶和固液分離步驟（D )數次是有效。也就是，在結晶之後藉由固液分離獲得的 酚加合物進一步進行一或多次的下列酚加合物之溶解、結 晶和固液分離的步驟（D 〇 ，然後轉移到熱熔化步驟（E (D’）酚加合物之溶解、結晶和固液分離步驟 在步驟（D )中結晶和分離之酚加合物溶解在含酚溶 液中。在這個步驟中所使用的含酚溶液不特別地限制，含 -16- (13) (13)200407291 酚溶液的例子包括在濃縮步驟（c )回收的酚、洗滌在結 晶和固液分離（D )所產生的酚加合物之後的淸潔溶液、 洗滌在步驟（D ')後的步驟所產生的經結晶之酚加合物， 或相似物的固液分離所產生之酚加合物之後的母液或淸潔 溶液。 在步驟（D ')中，在步驟（D )獲得之酚加合物的結 晶與上述含酚溶液混合和加熱到約8 0到1 1 0 °C之溫度以 熱熔化在其中之酚加合物，藉此製備具有雙酚 A濃度適 合於結晶處理之含雙酚 A之溶液。如此製備的含雙酚 A 之溶液甚至在較低溫度顯現低黏度和，因此，可較容易地 處理和適合於使用過濾器過濾。 從含雙酚 A之溶液結晶酚加合物之後，包含經結晶 之酚加合物的漿料進行固液分離，然後如此分離的酚加合 物溶解於含酚溶液中，所得溶液再次進一步進行一或多次 之上述結晶和固體一分離步驟（D )。 (E )熱熔化步驟 在熱熔化步驟中，在加熱下熔化上述步驟（D )及（ D ')中結晶和分離之酚加合物。在這個步驟中，酚加合物 在約1 0 0到1 6 0 °C之溫度熱熔化以形成液狀熔化混合物。 (F )脫酚步驟 在脫酚步騾中，步驟（E )中的熱熔化之酚加合物在 減壓下蒸餾以從其除去酚且回收熔化態的雙酚A。在減壓 -17- 190 (14) 200407291 下的蒸餾通常可在1 · 3到1 3 . 3 kP a的壓力下於1 5 0至 °C的溫度完成。仍殘留在回收之雙酚A的殘餘酚可 蒸汽汽提方法除去。 (G )粒化步驟 在粒化步驟中，在上述步驟（F )所獲得之已熔 酚A使用粒化裝置例如噴霧乾燥器形成液滴，然後 和固化以獲得作爲產物的雙酣A。雙酣a之液滴係藉 霧或分散熔化雙酚A，然後以氮、空氣等冷卻而形成 因此，根據本發明之製備雙酚A的方法特徵在 吸入式皮帶過濾器從反應混合物移出母液同時經加熱 性氣體流導入上述固體-液體分離步驟（D )和（D，） 後’藉由其配衡從皮帶過濾器分離所得酚加合物。結 以疋、連續和有效率的方式回收雙酣 A與酣的高 加合物變成可能。 將參考下列實例更詳細地描述本發明。然而，應 下列實例只用以說明和不意欲用於限制本發明。 實例1 酚、丙酮和乙硫醇分別地以4 9 · 7噸/小時、3.7 小時和0 · 2 5噸/小時的進料速率連續地進料至塡充 子交換樹脂的反應器內，同時維持於7 5 t溫度。所 應混合物進料至低沸點物質移除步騾以從其除去主要 未反應丙酮之低沸點物質。然後，反應混合物進料至 藉由 化雙 冷卻 由噴 〇 經由 之惰 中之 果， 純度 注意 噸/ 陽離 得反 包括 濃縮 -18- (15) (15)200407291 步驟，其中蒸飽掉一部份的雙酚A和未反應酚以調節反 應混合物中雙酚A濃度到3 0重量％。如此獲得的雙酚A -濃縮溶液與水混合，然後冷卻且於4 5 °C攪拌下結晶以 製備雙酚A與酚的經結晶加合物。如此製備的含加合物 之漿料溶液，其保持在45。(：之溫度，倒在由得自Daiwa B 〇 s e k i股份有限公司且具有7 0 C C S之透氣性的丙烯過濾 布製成之水平無端皮帶過濾器上，該過濾器在60 °C包含 1，20 0 ppm氧且於2米/分鐘的運轉速度移動的氮流下在 箱子中適應，然後暴露於5 5 kP a的減壓下1 5秒以從其母 液分離雙酚A與酚之加合物的結晶。結果，從母液分離 之加合物的結晶在皮帶過濾器上形成具有8 2 mm厚度之 層。脫水加合物以除去仍黏著在其上之母液和然後以酚洗 滌約1 0秒二次（淸潔比：〇 · 7 5 )以進一步從其分離母液 和乾燥加合物。然後，由於其配衡，加合物從皮帶過濾器 的回轉端掉下，藉此獲得濕狀態的加合物。測量的結果， 確認濕加合物具有2 4.5重量％的液體含量。進一步地， 當以液相色層分析法測量加合物中之異構物的含量時，確 認母液的置換率爲9 8.7 %。除此之外，所得加合物被熔化 且進行測量其於1 7 5 °C 2 0分鐘的H a z e η色値。結果，確 認加合物具有A Ρ Η A 5。 同時，透氣性的單位C C S爲c c / c m2 / s e c的縮寫， 且表示空氣通過單位面積（1 cm2 )之過濾器布的量。 製備例1 -19- (16) 200407291 進行上述步驟（A )至（C )以連續地產生雙酚 濃縮溶液，然後從雙酚A -濃縮溶液產生雙酚A與酌 合物。 更特而言之，首先，在步驟（A )中，酚、丙酮 硫醇分別地以4 5 6 0 0克/小時、2 8 0克/小時和1 6克 時的進料速率連續地進料至塡充6 0 0克陽離子交換樹 反應器內，同時維持溫度於7 5 °C。所得反應混合物 至低沸點物質移除步驟（B )以從其除去主要包括未 丙酮之低沸點物質，藉此產生4,640克/小時的產率 要地由雙酣A和未反應酣組成之反應產物。然後， 縮步驟（C )中，於1 6 5 °C、5 3 · 3 kP a ( 4 0 0托）的壓 從反應產物移除一部份的以調節反應混合物中雙 濃度到3 0重量％。如此獲得的雙酚a 一濃縮溶液與 合’然後冷卻且於4 5 C擾梓下結晶以製備雙酣A與 經結晶加合物。 參考例1 如製備例1所獲得之包含酚雙A與酚加合物的 溶液 倒入Nutschein內，其中放置得自Daiwa Boseki 有限公司和具有7 〇 C C S之透氣性的丙烯過濾布，在 包含1，200 ppm氧的氮壓下，於45 °C液溫在55 kPa 壓下以從母液分離雙酚A與酚之加合物的結晶。然 淸潔之酚倒在從其母液分離之加合物的結晶上於所得 A — 的加 和乙 /小 脂的 進料 反應 之主 在濃 力下 酚 A 水混 酚的 漿料 股份 4 5〇C 的減 後， 濕餅 -20- (17) (17)200407291 之量的約0.7 5倍的量之後，加合物的結晶連續吸約1 5秒 。結果，加合物的結晶以具有64 mm厚度的濾餅之形式 沈積在過濾布上。將所得濾餅切口，且藉由施用輕衝擊切 口取樣小塊濾餅。測量的結果，確認如此所得的加合物具 有 2 5 · 2重量％之液體含量。進一地，以液相色層分析法 測量加合物中之異構物含量的結果，確認母液的置換率爲 9 9 · 1 %。除此之外，所得加合物被熔化且進行測量其於 1 75 °C 20分鐘的Hazen色値。結果，確認加合物具有 APHA5。 從上述步驟，認知實例1也可使用Nut sche重覆製備 參考例2 嘗試以和參考例1相同的方法過濾，除了使用常壓代 替減壓之外。然而，母液仍保留在過濾器布上，且分離成 二層，所以不可能分離加合物和母液。 參考例3 重複與參考例1相同的方法，除了使用具有參考例1中所 使用之Nutsche的直徑之1/2倍的直徑之Nutsche代替 其之外。結果’確認所得濾餅厚度爲1 5 mm，濾餅中液體 含量爲38重量％，及母液的替換率爲955%。 參考例4 -21 - (18) (18)200407291 在漿料使用與參考例1所使之相同裝置在減壓下處理 之後，壓縮所得濾餅以壓實及從其分離母液。取樣一部份 濾餅及測量其液體含量。結果，確認液體含量爲〗5重量 %。然後，淸潔之酚倒在濾餅上，然後連續吸濾餅約15 秒。結果，確認所得的餅厚度爲5 5 mm，濾餅中液體含量 爲21重量％，及母液的替換率爲84%。 從上述結果，認知當濾餅太硬時，淸潔溶液不充份穿 入加合物的結晶經短時間，因此不能完全除去黏著在結晶 上的母液。 工業適用性 如所上所述，在根據本發明製備雙酚A的方法中， 在固液分離步驟（D )和（D 〇中，雙酚A與酚之加合物 的結晶可穩定且連續地從母液分離，所以可能以高效率回 收其局純度結晶。 因此，本發明有助於製備雙酚A的裝置之穩定操作 ’藉此使其可能以高效率製備高純度雙酚A。 -22-In order to obtain a high-purity product, it is effective to repeat the crystallization and solid-liquid separation step (D) several times. That is, the phenol adduct obtained by solid-liquid separation after crystallization is further subjected to one or more steps of dissolving, crystallizing, and solid-liquid separation of the following phenol adducts (D0, and then transferred to the thermal melting step ( E (D ') phenol adduct dissolution, crystallization and solid-liquid separation steps The phenol adduct crystallized and separated in step (D) is dissolved in a phenol-containing solution. The phenol-containing solution used in this step is not Particularly limited, examples of the phenol solution containing -16- (13) (13) 200407291 include the phenol recovered in the concentration step (c), washing of the phenol adduct produced after crystallization and solid-liquid separation (D) Cleaning solution, washing the crystallized phenol adduct produced in the step after step (D ′), or the mother liquor or cleaning solution after the phenol adduct produced by solid-liquid separation of the analogue. In step (D In '), the crystal of the phenol adduct obtained in step (D) is mixed with the above-mentioned phenol-containing solution and heated to a temperature of about 80 to 110 ° C to thermally melt the phenol adduct therein, thereby Preparation of a solution containing bisphenol A having a concentration of bisphenol A suitable for crystallization. The prepared solution containing bisphenol A exhibits low viscosity and even at lower temperatures, so it can be handled more easily and is suitable for filtration using a filter. After crystallizing the phenol adduct from the solution containing bisphenol A, The phenol adduct slurry was subjected to solid-liquid separation, and the thus separated phenol adduct was dissolved in a phenol-containing solution, and the resulting solution was further subjected to one or more of the above-mentioned crystallization and solid-separation step (D). E) Hot melting step In the hot melting step, the phenol adduct crystallized and separated in the above steps (D) and (D ') are melted under heating. In this step, the phenol adduct is about 100 to Thermally melt at a temperature of 160 ° C to form a liquid molten mixture. (F) Dephenolization step In the dephenolization step, the hot-melted phenol adduct in step (E) is distilled under reduced pressure to remove from it. Removes phenol and recovers molten bisphenol A. Distillation under reduced pressure -17- 190 (14) 200407291 can usually be performed at a temperature of 1 · 3 to 1 3. 3 kPa at a temperature of 150 to ° C Complete. Residual phenol remaining in the recovered bisphenol A can be removed by steam stripping. (G) Granulation step In the granulation step, the melted phenol A obtained in the above step (F) is formed into droplets using a granulation device such as a spray drier, and then solidified to obtain the double-fluorene A as a product. The double-fluorine a droplet system It is formed by melting or dispersing bisphenol A and then cooling it with nitrogen, air, etc. Therefore, the method for preparing bisphenol A according to the present invention is characterized in that the mother liquid is removed from the reaction mixture by a suction belt filter while being introduced into the above through a heating gas stream After the solid-liquid separation steps (D) and (D,) ', the resulting phenol adduct is separated from the belt filter by its balance. The high addition of double hydrazone A and hydrazone is recovered in a rhenium, continuous, and efficient manner. Compound becomes possible. The present invention will be described in more detail with reference to the following examples. However, the following examples should be used for illustration only and are not intended to limit the present invention. Example 1 Phenol, acetone, and ethyl mercaptan were continuously fed into a reactor of an ammonium exchange resin at feed rates of 49,7 ton / hour, 3.7 hours, and 0.25 ton / hour, respectively, while maintaining At a temperature of 7 5 t. The resulting mixture is fed to a low boiling point material removal step to remove the low boiling point material which is mainly unreacted acetone therefrom. Then, the reaction mixture was fed to the fruit in the inertia by spray cooling through double cooling, the purity was noted ton / anion, including the step of concentrating -18- (15) (15) 200407291, in which one part was steamed off. Parts of bisphenol A and unreacted phenol to adjust the bisphenol A concentration in the reaction mixture to 30% by weight. The bisphenol A-concentrated solution thus obtained was mixed with water, then cooled and crystallized with stirring at 45 ° C to prepare a crystallized adduct of bisphenol A and phenol. The adduct-containing slurry solution thus prepared was maintained at 45. (: The temperature is poured on a horizontal endless belt filter made of acrylic filter cloth with air permeability of 70 CCS from Daiwa Boseki Co., Ltd., the filter contains 1,20 0 at 60 ° C ppm oxygen and adapted in a box under a nitrogen flow moving at a running speed of 2 m / min, and then exposed to a reduced pressure of 55 kPa for 15 seconds to separate the crystals of the adduct of bisphenol A and phenol from its mother liquor As a result, the crystals of the adduct separated from the mother liquor formed a layer having a thickness of 82 mm on the belt filter. The adduct was dehydrated to remove the mother liquor still stuck to it and then washed twice with phenol for about 10 seconds (Clean ratio: 0.75) to further separate the mother liquor and the dry adduct therefrom. Then, due to its balance, the adduct falls off the rotating end of the belt filter, thereby obtaining a wet state adduct As a result of the measurement, it was confirmed that the wet adduct had a liquid content of 24.5% by weight. Further, when the content of the isomer in the adduct was measured by liquid chromatography, the replacement ratio of the mother liquor was confirmed 9 8.7%. In addition, the resulting adduct is melted and The Haze η color at 20 minutes of 17.5 ° C was measured. As a result, it was confirmed that the adduct had A P Η A 5. At the same time, the unit of air permeability CCS is an abbreviation of cc / cm 2 / sec, and Indicates the amount of air passing through the filter cloth per unit area (1 cm2). Preparation Example 1 -19- (16) 200407291 The above steps (A) to (C) were performed to continuously produce a bisphenol concentrated solution, and then from bisphenol A -Concentrating the solution produces bisphenol A and the appropriate compound. More specifically, first, in step (A), the phenol and acetone mercaptan are respectively 4600 g / hour and 280 g / hour. And a feed rate of 16 grams were continuously fed into a cation exchange tree reactor filled with 600 grams of argon, while maintaining the temperature at 75 ° C. The obtained reaction mixture was subjected to a low boiling point removal step (B) to Low-boiling substances mainly including unacetone were removed therefrom, thereby producing a reaction product consisting mainly of difluorene A and unreacted fluorene in a yield of 4,640 g / hr. Then, in step (C), the temperature was reduced to 1 6 5 ° C, 5 3 · 3 kP a (400 torr) pressure to remove part of the reaction product to adjust the double concentration in the reaction mixture To 30% by weight. The thus-obtained bisphenol a concentrated solution was combined and then cooled and crystallized at 45 ° C. to prepare bis-A and crystallized adduct. Reference Example 1 Obtained as in Preparation Example 1 The solution containing phenolic A and a phenol adduct was poured into Nutschein, in which a propylene filter cloth with air permeability of Daiwa Boseki Co., Ltd. and 70 CCS was placed under a nitrogen pressure of 1,200 ppm oxygen, The crystals of the adduct of bisphenol A and phenol were separated from the mother liquor at a liquid temperature of 45 ° C under a pressure of 55 kPa. However, the clean phenol is poured on the crystals of the adduct separated from its mother liquor, and the obtained A — is the main reaction of the feed reaction with B / small fat. The concentration of phenol A is a slurry of water-soluble phenol. 4 5 After the reduction of OC, the amount of wet cake-20- (17) (17) 200407291 was about 0.7 5 times, and the crystals of the adduct were continuously sucked for about 15 seconds. As a result, crystals of the adduct were deposited on the filter cloth in the form of a filter cake having a thickness of 64 mm. The resulting filter cake was cut and a small piece of filter cake was sampled by applying a light impact cut. As a result of the measurement, it was confirmed that the adduct thus obtained had a liquid content of 25.2% by weight. Furthermore, as a result of measuring the content of the isomers in the adduct by liquid chromatography, it was confirmed that the replacement ratio of the mother liquor was 99 · 1%. In addition, the obtained adduct was melted and measured for a Hazen color tint at 1 75 ° C for 20 minutes. As a result, it was confirmed that the adduct had APHA5. From the above steps, Cognitive Example 1 can also be prepared repeatedly using Nutsche. Reference Example 2 An attempt was made to filter in the same manner as in Reference Example 1, except that atmospheric pressure was used instead of reduced pressure. However, the mother liquor remained on the filter cloth and separated into two layers, so it was impossible to separate the adduct and the mother liquor. Reference Example 3 The same method as in Reference Example 1 was repeated, except that a Nutsche having a diameter which is 1/2 times the diameter of the Nutsche used in Reference Example 1 was used instead. As a result, it was confirmed that the thickness of the obtained filter cake was 15 mm, the liquid content in the filter cake was 38% by weight, and the replacement ratio of the mother liquor was 955%. Reference Example 4 -21-(18) (18) 200407291 After the slurry was processed under reduced pressure using the same device as that used in Reference Example 1, the obtained filter cake was compressed to compact and separate the mother liquor therefrom. Take a portion of the filter cake and measure its liquid content. As a result, it was confirmed that the liquid content was 5 wt%. Then, pour phenol into the filter cake, and then suck the filter cake continuously for about 15 seconds. As a result, it was confirmed that the thickness of the obtained cake was 55 mm, the liquid content in the filter cake was 21% by weight, and the replacement ratio of the mother liquor was 84%. From the above results, it is recognized that when the filter cake is too hard, the cleaning solution does not sufficiently penetrate the crystals of the adduct over a short period of time, and therefore the mother liquor adhering to the crystals cannot be completely removed. Industrial Applicability As described above, in the method for preparing bisphenol A according to the present invention, in the solid-liquid separation steps (D) and (D0), the crystallization of the adduct of bisphenol A and phenol can be stable and continuous It is separated from the mother liquor, so it is possible to recover its local purity crystals with high efficiency. Therefore, the present invention contributes to the stable operation of the apparatus for preparing bisphenol A ', thereby making it possible to produce high purity bisphenol A with high efficiency. -22 -