JPH11228492A - Recovery of terephthalic acid - Google Patents
Recovery of terephthalic acidInfo
- Publication number
- JPH11228492A JPH11228492A JP10030863A JP3086398A JPH11228492A JP H11228492 A JPH11228492 A JP H11228492A JP 10030863 A JP10030863 A JP 10030863A JP 3086398 A JP3086398 A JP 3086398A JP H11228492 A JPH11228492 A JP H11228492A
- Authority
- JP
- Japan
- Prior art keywords
- terephthalic acid
- crystallization tank
- temperature
- stage
- crystallization
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C63/00—Compounds having carboxyl groups bound to a carbon atoms of six-membered aromatic rings
- C07C63/14—Monocyclic dicarboxylic acids
- C07C63/15—Monocyclic dicarboxylic acids all carboxyl groups bound to carbon atoms of the six-membered aromatic ring
- C07C63/26—1,4 - Benzenedicarboxylic acid
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C51/00—Preparation of carboxylic acids or their salts, halides or anhydrides
- C07C51/42—Separation; Purification; Stabilisation; Use of additives
- C07C51/43—Separation; Purification; Stabilisation; Use of additives by change of the physical state, e.g. crystallisation
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C51/00—Preparation of carboxylic acids or their salts, halides or anhydrides
- C07C51/42—Separation; Purification; Stabilisation; Use of additives
- C07C51/487—Separation; Purification; Stabilisation; Use of additives by treatment giving rise to chemical modification
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- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Engineering & Computer Science (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Crystallography & Structural Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- General Chemical & Material Sciences (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明はテレフタル酸の製造
方法に関し、特に、パラキシレンの酸化反応によって得
られた粗テレフタル酸の水溶液を第VIII族金属触媒の存
在下、水素を用いて精製し、高純度のテレフタル酸を得
るテレフタル酸の回収方法に関するものである。The present invention relates to a method for producing terephthalic acid, and more particularly to a method for purifying an aqueous solution of crude terephthalic acid obtained by an oxidation reaction of para-xylene using hydrogen in the presence of a Group VIII metal catalyst. The present invention relates to a method for recovering terephthalic acid to obtain high-purity terephthalic acid.
【０００２】[0002]
【従来の技術】パラキシレンの酸化によって得られる粗
テレフタル酸中には、４−ＣＢＡ、ｐ−トルイル酸等の
不純物が多量に含有されており、従来これらを精製した
後、ポリエステルの原料として用いている。2. Description of the Related Art Crude terephthalic acid obtained by oxidation of para-xylene contains a large amount of impurities such as 4-CBA and p-toluic acid. ing.
【０００３】テレフタル酸の精製方法として、高温・高
圧下にて粗テレフタル酸の水溶液をＰｄ、Ｐｔ等の第VI
II族金属触媒の存在下に水素を用いて還元処理し、処理
された水溶液からテレフタル酸の結晶を回収する方法が
知られている（特公昭４１−１６８６０号公報）。[0003] As a method for purifying terephthalic acid, an aqueous solution of crude terephthalic acid is converted to a terephthalic acid solution such as Pd, Pt, etc.
There is known a method of performing a reduction treatment using hydrogen in the presence of a group II metal catalyst and recovering terephthalic acid crystals from the treated aqueous solution (Japanese Patent Publication No. 41-16860).
【０００４】テレフタル酸の結晶を回収する方法として
は、回分式、連続式の方法が知られている（英特許第１
１５２５７５号公報）。回分式の方法は高純度のテレフ
タル酸を生産するためには有効であるが、テレフタル酸
を多量に生産する際には、操作上あるいは経済的に極め
て不利である。そのため工業的にテレフタル酸を生産す
る場合には、連続式の方法を用いるのが一般的であり、
連続フラッシュ結晶化法を利用し、テレフタル酸結晶の
回収温度が次工程である固液分離工程の処理温度と同一
になるまで、それぞれ段階的温度の低下で操作される２
個またはそれ以上を直列に接続される晶析槽を用いる方
法が知られている（特開昭５０−４９２４８号公報）。As a method for recovering terephthalic acid crystals, a batch method and a continuous method are known (English Patent No. 1).
No. 152575). The batch method is effective for producing high-purity terephthalic acid, but is extremely disadvantageous in terms of operation or economy when producing a large amount of terephthalic acid. Therefore, when producing terephthalic acid industrially, it is common to use a continuous method,
Using a continuous flash crystallization method, each operation is carried out at a stepwise lowering temperature until the recovery temperature of the terephthalic acid crystals becomes the same as the processing temperature of the subsequent solid-liquid separation step.
A method using a crystallization tank in which pieces or more are connected in series is known (JP-A-50-49248).
【０００５】固液分離の方法としては、晶析槽により生
成されたテレフタル酸のスラリーを晶析槽の最終温度及
び圧力において遠心分離又は濾過する方法が知られてお
り、１段目の固液分離、リスラリー、２段目の固液分離
の工程を経て、乾燥工程に送り、テレフタル酸を得る方
法が知られている（特公昭４７−４９０４９号公報）。As a method of solid-liquid separation, there is known a method of centrifuging or filtering a slurry of terephthalic acid produced in a crystallization tank at the final temperature and pressure of the crystallization tank. A method of obtaining terephthalic acid through a separation, reslurry, a second-stage solid-liquid separation step, and a drying step is known (Japanese Patent Publication No. 47-49049).
【０００６】また、固液分離の方法として、加圧下の状
態において、洗浄装置付きの濾過装置を用いて、高純度
テレフタル酸を得る方法もいくつか知られている（特開
平１−２９９６１８号公報、特開平５−６５２４６号公
報、特表平６−５０６４６１号公報）。Further, as a method of solid-liquid separation, there are also known some methods of obtaining high-purity terephthalic acid by using a filtration device with a washing device under a pressurized state (Japanese Patent Application Laid-Open No. 1-299618). JP-A-5-65246 and JP-A-6-506461.
【０００７】[0007]
【発明が解決しようとする課題】水素化精製反応におい
て、粗テレフタル酸中の４−ＣＢＡは、第VIII族金属触
媒の存在下で、水素により、大部分ｐ−トルイル酸に還
元される。そのため晶析系では、フラッシュ冷却法を利
用して、温度を段階的に低下させ、ｐ−トルイル酸など
の不純物の少ない高純度なテレフタル酸の結晶を得る必
要がある。このとき問題になるのは、テレフタル酸結晶
中に共晶すると考えられるｐ−トルイル酸であり、飽和
にも達しない充分な水が保持されているにも関わらず、
テレフタル酸結晶中に包含されてくる。In the hydrorefining reaction, 4-CBA in crude terephthalic acid is largely reduced to p-toluic acid by hydrogen in the presence of a Group VIII metal catalyst. Therefore, in the crystallization system, it is necessary to lower the temperature stepwise by using a flash cooling method to obtain high-purity terephthalic acid crystals with few impurities such as p-toluic acid. At this time, the problem is p-toluic acid, which is considered to be eutectic in the terephthalic acid crystal, and although sufficient water that does not reach saturation is retained,
It is included in terephthalic acid crystals.
【０００８】テレフタル酸の結晶に包含するｐ−トルイ
ル酸の共晶などを防ぎ、品質的に満足する高純度テレフ
タル酸を製造するために、各晶析槽の操作条件について
制御する必要がある。[0008] In order to prevent the eutectic of p-toluic acid contained in the crystals of terephthalic acid and to produce high-purity terephthalic acid having satisfactory quality, it is necessary to control the operating conditions of each crystallization tank.
【０００９】本発明の目的は高純度のテレフタル酸を連
続的に製造することができるテレフタル酸の回収方法を
提供するにある。It is an object of the present invention to provide a method for recovering terephthalic acid which can continuously produce high-purity terephthalic acid.
【００１０】[0010]
【課題を解決するための手段】以上の問題点に鑑み、本
発明では、濃度が２２〜３０ｗｔ％の粗テレフタル酸の
水スラリーを２７０〜３００℃に昇温し、完全に溶解し
たのち水添反応し、反応後テレフタル酸水溶液を３乃至
５段の晶析槽に順次供給し、各段の晶析槽の操作温度を
次の近似式で表される値に選び、ｙ＝２６６ｅｘｐ（−
０．６１ｘ）±５；［ｘ：１を総段数で分割した値に各
段の段数値を乗じた値，ｙ：温度（ oＣ）］、第１晶析
槽の温度を２４０℃に満たない温度として、各晶析槽の
平均滞留時間を１０〜６０分とし、各槽へは該滞留液相
部へのテレフタル酸水溶液またはスラリーを供給し、最
終段の晶析槽から得られたスラリーを固液分離して、高
純度のテレフタル酸を得る方法である。In view of the above problems, the present invention raises the temperature of a crude terephthalic acid aqueous slurry having a concentration of 22 to 30% by weight to 270 to 300 ° C., dissolves it completely, and hydrogenates it. After the reaction, an aqueous terephthalic acid solution is sequentially supplied to three to five stages of crystallization tanks, and the operating temperature of each stage of crystallization tank is selected to a value represented by the following approximate expression, and y = 266exp (−
0.61x) ± 5; [x: the value obtained by dividing the value obtained by dividing the total number of steps by the total number of steps, y: temperature ( ° C.)], and the temperature of the first crystallization tank to 240 ° C. As the temperature, the average residence time of each crystallization tank was set to 10 to 60 minutes, and the terephthalic acid aqueous solution or slurry to the retained liquid phase was supplied to each tank, and the slurry obtained from the crystallization tank at the final stage was used. To obtain high-purity terephthalic acid by solid-liquid separation.
【００１１】ｐ−キシレンを液相酸化して得られた粗テ
レフタル酸を水溶液中に完全溶解させ、該水溶液を第VI
II族金属触媒の存在下で、水素と接触させる水添反応に
より精製される。粗テレフタル酸中の４−ＣＢＡなどの
不純物は、ポリエステル製品の着色原因となり、また、
これらの不純物はテレフタル酸の結晶に共晶包含しやす
い性質を有するため、上記反応で、４−ＣＢＡがｐ−ト
ルイル酸に転化され、またその他の不純物は水素化分解
精製される。そして、水添反応後の該水溶液は晶析系に
送られる。晶析系は直列に接続された複数段の晶析槽よ
り構成されており、フラッシュ蒸発を利用して、高純度
のテレフタル酸結晶を得る。本発明は、この晶析系にお
いて、品質を満足するために、各晶析槽の最適操作条件
を提供するものである。The crude terephthalic acid obtained by liquid-phase oxidation of p-xylene is completely dissolved in an aqueous solution, and
Purified by hydrogenation reaction with hydrogen in the presence of a Group II metal catalyst. Impurities such as 4-CBA in the crude terephthalic acid cause coloring of the polyester product,
Since these impurities have a property of being easily eutectically included in the crystals of terephthalic acid, 4-CBA is converted to p-toluic acid by the above reaction, and other impurities are hydrocracked and purified. Then, the aqueous solution after the hydrogenation reaction is sent to a crystallization system. The crystallization system is composed of a plurality of crystallization tanks connected in series, and obtains high-purity terephthalic acid crystals using flash evaporation. The present invention provides optimum operation conditions of each crystallization tank in order to satisfy the quality in this crystallization system.
【００１２】このような精製法において、２２〜３０ｗ
ｔ％の粗テレフタル酸水スラリーを完全に溶解し、水溶
液とするには２７０〜３００℃近辺の温度を必要とし、
そして該水溶液を液状で存在させるためには該水溶液の
蒸気圧、大略水の蒸気圧以上を保持して水素化精製が行
われる。In such a purification method, 22 to 30 w
In order to completely dissolve the crude terephthalic acid aqueous slurry of t% and to prepare an aqueous solution, a temperature around 270 to 300 ° C. is required,
Then, in order to make the aqueous solution exist in a liquid state, hydrorefining is performed while maintaining the vapor pressure of the aqueous solution, which is substantially higher than that of water.
【００１３】その後、高温・高圧状態の該テレフタル酸
水溶液からテレフタル酸を晶析させるに際して、水素化
によって還元されたｐ−トルイル酸に代表される不純物
が共晶などでテレフタル酸の結晶粒子に包含され、純度
低下を起こすことは前述の特許公報などで明らかであ
る。Thereafter, when terephthalic acid is crystallized from the terephthalic acid aqueous solution in a high temperature and high pressure state, impurities typified by p-toluic acid reduced by hydrogenation are included in terephthalic acid crystal particles as eutectics. It is clear from the above-mentioned patent publications that the purity is lowered.
【００１４】そこで、水素化精製において用いられる濃
度が２２〜３０ｗｔ％の水スラリーを用いて、晶析操作
における晶析条件について種々検討した結果、共晶など
によりテレフタル酸結晶粒子に包含されるｐ−トルイル
酸などの不純物は液相中の不純物濃度に影響されること
は勿論であるが、操作として温度、即ち、各晶析槽操作
温度におけるテレフタル酸の晶析の割合に最も影響を受
け、高温で晶析されるほどｐ−トルイル酸の包含は少な
く、低温になるに従ってｐ−トルイル酸の包含が著し
い。特に１４０〜１５０℃を下回るとｐ−トルイル酸量
が飛躍的に増大することもわかった。Thus, as a result of various investigations on the crystallization conditions in the crystallization operation using a water slurry having a concentration of 22 to 30% by weight used in hydrorefining, it was found that the p-type particles contained in the terephthalic acid crystal particles by eutectic or the like. -Impurities such as toluic acid are affected not only by the impurity concentration in the liquid phase, but also by operation, that is, the rate of terephthalic acid crystallization at each crystallization tank operating temperature, The higher the temperature of crystallization, the lower the content of p-toluic acid. The lower the temperature, the more the content of p-toluic acid. In particular, it was also found that when the temperature was lower than 140 to 150 ° C., the amount of p-toluic acid increased dramatically.
【００１５】一方、テレフタル酸の晶析回収量から評価
すると、最終晶析槽、即ち晶析テレフタル酸スラリーを
固液分離する工程に導入する槽の温度が低くした方が好
ましい。On the other hand, when evaluated from the amount of terephthalic acid crystallized and recovered, it is preferable to lower the temperature of the final crystallization tank, that is, the tank for introducing the crystallization terephthalic acid slurry into a solid-liquid separation step.
【００１６】これら温度における二律背反の操作を考慮
し、３〜５段の晶析槽を用いて高純度で回収率の高いテ
レフタル酸を得る為に前記近似式に沿って温度制御する
ことが好ましい傾向のあることを発見した。そして３〜
５段の晶析槽で温度制御するためには、第１段目の晶析
槽を２４０℃未満に設定することが望ましいこともわか
った。In consideration of the trade-off operation at these temperatures, in order to obtain terephthalic acid of high purity and high recovery using a crystallization tank of three to five stages, it is preferable to control the temperature in accordance with the above approximate expression. I found that there is. And 3 ~
It was also found that it is desirable to set the temperature of the first crystallization tank to less than 240 ° C. in order to control the temperature in the five crystallization tanks.
【００１７】さらにその他の操作条件としては、各晶析
槽の滞留時間に影響を受け、最低でも１０分間は保持す
る必要がある。滞留時間が１０分より短いと、結晶が生
長せず、かつ結晶中に包含される不純物量も多くなると
いう傾向にあることを発見した。そして、滞留時間をあ
まり大きくしても、大きな効果はなく装置的なバランス
から６０分程度までが適当であろう。Still other operating conditions are affected by the residence time of each crystallization tank, and must be maintained for at least 10 minutes. It has been discovered that if the residence time is shorter than 10 minutes, the crystals do not grow and the amount of impurities contained in the crystals tends to increase. Even if the residence time is too long, there is no great effect, and it is appropriate that the residence time is up to about 60 minutes from the balance of the apparatus.
【００１８】次に各晶析槽への水溶液およびスラリーの
供給は、各槽滞留液の液相部に送入、フラッシュ冷却さ
せることが重要となる。即ちフラッシュ冷却によりテレ
フタル酸結晶粒子の中に包含させないためにも発生結晶
を分散、生長させる。その際、結晶核となるテレフタル
酸結晶粒子をあらかじめ存在させる必要がある。Next, when supplying the aqueous solution and slurry to each crystallization tank, it is important to feed them into the liquid phase portion of the stagnant liquid in each tank and to perform flash cooling. That is, the generated crystals are dispersed and grown so as not to be included in the terephthalic acid crystal particles by flash cooling. At that time, terephthalic acid crystal particles serving as crystal nuclei need to be present in advance.
【００１９】最終段の晶析槽の操作温度を１４０〜１５
０℃とし、この温度・圧力で１段目の固液分離を行い、
さらにリスラリー用の水を追加し、操作圧力を常圧まで
低下させ、２段目の固液分離を行いテレフタル酸を回収
する方法が好ましい。The operating temperature of the crystallization tank at the final stage is 140 to 15
0 ° C and the first stage of solid-liquid separation at this temperature and pressure.
Further, a method of adding water for reslurry, lowering the operating pressure to normal pressure, and performing the second-stage solid-liquid separation to recover terephthalic acid is preferable.
【００２０】何らかの理由で、最終段の晶析槽の操作温
度を下げる必要がある場合には、水で希釈することによ
り、テレフタル酸結晶中に包含されるｐ−トルイル酸等
の不純物量を減少させることができる。特に常圧まで温
度を下げる必要がある場合には最終段晶析槽中のテレフ
タル酸スラリーと同量以上の水を送入することにより、
品質的に満足するテレフタル酸を回収することができ
る。If, for some reason, it is necessary to lower the operating temperature of the crystallization tank in the final stage, the amount of impurities such as p-toluic acid contained in the terephthalic acid crystals is reduced by diluting with water. Can be done. In particular, when it is necessary to lower the temperature to normal pressure, by feeding water of the same amount or more as the terephthalic acid slurry in the final stage crystallization tank,
Terephthalic acid satisfying quality can be recovered.
【００２１】さらに常圧下で、洗浄装置付きの固液分離
装置と組み合わせることにより、固液分離装置を１段と
することがでる。リスラリー及び２段目の固液分離工程
が不要となり、１段目の固液分離工程に常圧の装置を用
いることが可能となるため、その経済的効果は大きい。Further, by combining with a solid-liquid separation device equipped with a washing device under normal pressure, the solid-liquid separation device can be made one stage. The reslurry and the second solid-liquid separation step are not required, and a normal-pressure apparatus can be used in the first solid-liquid separation step.
【００２２】これらの操作条件を制御すれば、水素化精
製反応により得られたテレフタル酸水溶液から高純度の
テレフタル酸を回収することができる。By controlling these operating conditions, high-purity terephthalic acid can be recovered from the terephthalic acid aqueous solution obtained by the hydrorefining reaction.
【００２３】[0023]
【発明の実施の形態】実施例１：図１に示す装置を用い
て、高純度テレフタル酸を製造した。原料として用いた
粗テレフタル酸（ＣＴＡ）中の不純物（４−ＣＢＡ，ｐ
−トルイル酸等）の量は、テレフタル酸に対して、約
３，０００ｐｐｍ−ｗｔである。このＣＴＡはＣＴＡ混
合槽１において、イオン交換水と混合され２５ｗｔ％の
濃度のテレフタル酸水スラリーとなる。混合されたテレ
フタル酸水スラリーは、水溶媒が蒸発しないように加圧
（約９０ｋｇ／ｃｍ2Ｇ）し、約２８５oＣまで加熱され
る。加熱されたＣＴＡスラリーはＣＴＡ溶解槽３におい
て一時的に滞留され溶解の完全化が確保される。次いで
完全溶解したＣＴＡ水溶液は市販のＰｄ／Ｃ触媒を充填
した水添反応槽４に通され、ＣＴＡ水溶液中の４−ＣＢ
Ａはほぼ全量ｐ−トルイル酸に還元される。DESCRIPTION OF THE PREFERRED EMBODIMENTS Example 1: High-purity terephthalic acid was produced using the apparatus shown in FIG. The impurity (4-CBA, p) in crude terephthalic acid (CTA) used as a raw material
-Toluic acid) is about 3,000 ppm-wt, based on terephthalic acid. The CTA is mixed with ion-exchanged water in the CTA mixing tank 1 to form a 25% by weight terephthalic acid aqueous slurry. The mixed terephthalic acid aqueous slurry is pressurized (about 90 kg / cm 2 G) so that the water solvent does not evaporate, and heated to about 285 ° C. The heated CTA slurry temporarily stays in the CTA dissolution tank 3 to ensure complete dissolution. Next, the completely dissolved CTA aqueous solution is passed through a hydrogenation reaction tank 4 filled with a commercially available Pd / C catalyst, and 4-CB in the CTA aqueous solution is removed.
A is almost completely reduced to p-toluic acid.
【００２４】水添反応後のテレフタル酸溶液は、１段目
晶析槽５、２段目晶析槽６、３段目晶析槽７、４段目晶
析槽８、５段目晶析槽９なる晶析系の液相部に供給さ
れ、圧力制御により徐々に減圧温度降下された。そして
各晶析槽の滞留時間は２０〜４０分とした。The terephthalic acid solution after the hydrogenation reaction is supplied to the first-stage crystallization tank 5, the second-stage crystallization tank 6, the third-stage crystallization tank 7, the fourth-stage crystallization tank 8, and the fifth-stage crystallization tank. The liquid was supplied to the liquid phase portion of the crystallization system serving as the tank 9, and the pressure was gradually reduced by the pressure control. The residence time in each crystallization tank was set to 20 to 40 minutes.
【００２５】５段目晶析槽９から得られたテレフタル酸
を多量に含むテレフタル酸溶液はブロック１０において
固液分離・乾燥され、最終製品である高純度テレフタル
酸が回収される。The terephthalic acid solution containing a large amount of terephthalic acid obtained from the fifth-stage crystallization tank 9 is subjected to solid-liquid separation and drying in a block 10 to recover a high-purity terephthalic acid as a final product.
【００２６】晶析槽の段数を５段とおき、各晶析槽の操
作温度を表１のように行ったときの高純度テレフタル酸
中のｐ−トルイル酸含有量を示す。The content of p-toluic acid in high-purity terephthalic acid when the number of stages in the crystallization tank is set to five and the operation temperature of each crystallization tank is as shown in Table 1 is shown.
【００２７】実施例２および３：実施例１の方法におい
て、実施例２は４段目晶析槽８を実施例３は３段目晶析
槽７，４段目晶析槽８をバイパスして行った。各晶析槽
の操作温度および回収テレフタル酸中のｐ−トルイル酸
含有量を表１に示す。Examples 2 and 3: In the method of Example 1, Example 2 bypasses the fourth-stage crystallization tank 8, and Example 3 bypasses the third-stage crystallization tank 7 and the fourth-stage crystallization tank 8. I went. Table 1 shows the operating temperature of each crystallization tank and the content of p-toluic acid in the recovered terephthalic acid.
【００２８】[0028]
【表１】 [Table 1]
【００２９】比較例１，２および５：実施例１の方法に
おいて、各晶析槽の操作温度を表１のように変え行っ
た。得られた回収テレフタル酸中のｐ−トルイル酸含有
量は、表１に示す通りとなった。Comparative Examples 1, 2 and 5: In the method of Example 1, the operation temperature of each crystallization tank was changed as shown in Table 1. The content of p-toluic acid in the obtained recovered terephthalic acid was as shown in Table 1.
【００３０】比較例３：実施例１の方法において各晶析
槽の液相面を下げ滞留時間を約５分に調節し行った。結
果は表１に示す通りである。Comparative Example 3 In the method of Example 1, the liquid phase surface of each crystallization tank was lowered and the residence time was adjusted to about 5 minutes. The results are as shown in Table 1.
【００３１】比較例４：実施例１の方法において、各晶
析槽への供給液送入を気相部に出し行った。結果は表１
に示す通りである。COMPARATIVE EXAMPLE 4 In the method of Example 1, the supply of the liquid to each crystallization tank was carried out to the gas phase. Table 1 shows the results
As shown in FIG.
【００３２】実施例４：比較例５の方法において、４段
目の晶析槽に保持されているテレフタル酸スラリーと同
量のイオン交換水を５段目の晶析槽に供給した。結果は
表１に示す通りである。Example 4: In the method of Comparative Example 5, the same amount of ion-exchanged water as the terephthalic acid slurry held in the fourth crystallization tank was supplied to the fifth crystallization tank. The results are as shown in Table 1.
【００３３】比較例６：実施例１の方法において、ＣＴ
Ａ混合槽におけるＣＴＡスラリーを２０ｗｔ％に混合調
整した。各晶析槽の操作温度及び回収テレフタル酸中の
ｐ−トルイル酸含有量を表１示す。Comparative Example 6: In the method of Example 1, CT
The CTA slurry in the A mixing tank was mixed and adjusted to 20 wt%. Table 1 shows the operating temperature of each crystallization tank and the content of p-toluic acid in the recovered terephthalic acid.
【００３４】実施例５：実施例１の方法において、ＣＴ
Ａ混合槽におけるＣＴＡスラリーを２８ｗｔ％に混合調
整した。各晶析槽の操作温度及び回収テレフタル酸中の
ｐ−トルイル酸含有量を表１示す。Embodiment 5: In the method of Embodiment 1, the CT
The CTA slurry in the A mixing tank was mixed and adjusted to 28 wt%. Table 1 shows the operating temperature of each crystallization tank and the content of p-toluic acid in the recovered terephthalic acid.
【００３５】[0035]
【発明の効果】本発明によれば、ｐ−トルイル酸の量と
析出するテレフタル酸結晶の量とのバランスが適切とな
るように、各晶析槽の温度の設定することができ、この
結果、所望の純度で所望の量の高純度テレフタル酸を得
ることができる。According to the present invention, the temperature of each crystallization tank can be set so that the balance between the amount of p-toluic acid and the amount of precipitated terephthalic acid crystals is appropriate. Thus, a desired amount of high-purity terephthalic acid can be obtained at a desired purity.
【図１】本発明によるテレフタル酸の回収方法の一実施
例を示すブロック系統図である。FIG. 1 is a block diagram showing one embodiment of a method for recovering terephthalic acid according to the present invention.
１…ＣＴＡ混合槽、２…ＣＴＡスラリー加熱器、３…Ｃ
ＴＡ溶解槽、４…水添反応槽、５…１段目晶析槽、６…
２段目晶析槽、７…３段目晶析槽、８…４段目晶析槽、
９…５段目晶槽、１０…固液分離・乾燥装置。1. CTA mixing tank, 2. CTA slurry heater, 3. C
TA dissolution tank, 4 ... hydrogenation reaction tank, 5 ... first-stage crystallization tank, 6 ...
Second-stage crystallization tank, 7 ... third-stage crystallization tank, 8 ... fourth-stage crystallization tank,
9: Fifth stage crystal tank, 10: Solid-liquid separation / drying device
Claims (3)
のスラリーを２７０〜３００℃の温度範囲で、第ＶＩＩ
Ｉ族金属触媒の存在下、水素化精製したのち、該テレフ
タル酸水溶液を直列に連結した３〜５段の晶析槽を用い
てフラッシュ蒸発冷却法により段階的に冷却してテレフ
タル酸を晶析回収する方法において第１晶析槽を２４０
℃に満たない温度に設定したのち各晶析槽の操作温度
を、下記の近似式で表される温度に沿って段階的に１４
０〜１５０℃まで冷却し、各晶析槽の平均滞留時間を１
０〜６０分とし、各晶析槽への供給を該滞留液相部に行
うことを特徴とするテレフタル酸の回収方法。 ｙ＝２６６ｅｘｐ（−０．６１ｘ）±５ ｘ：１を総段数で分割した値に各段の段数値を乗じた値 ｙ：晶析槽操作温度（℃）（１４０≦ｙ＜２４０）1. A slurry of a crude terephthalic acid having a concentration of 22 to 30% by weight in a temperature range of 270 to 300.degree.
After hydrorefining in the presence of a Group I metal catalyst, terephthalic acid is crystallized by stepwise cooling by flash evaporation cooling using a 3 to 5 stage crystallization tank in which the aqueous terephthalic acid solution is connected in series. In the recovery method, the first crystallization tank is set to 240
After setting the temperature to less than 0 ° C., the operating temperature of each crystallization tank was increased stepwise by 14 along the temperature represented by the following approximate expression.
After cooling to 0 to 150 ° C, the average residence time of each crystallization tank was 1
A method for recovering terephthalic acid, wherein the supply to each crystallization tank is performed in the retained liquid phase portion for 0 to 60 minutes. y = 266exp (-0.61x) ± 5 x: 1 is a value obtained by dividing a value obtained by dividing the total number of stages by a numerical value of each stage. y: Crystallization tank operating temperature (° C.) (140 ≦ y <240)
より１段前の晶析槽に保持されているテレフタル酸スラ
リーと同量以上の希釈水を送入し、最終段晶析槽の操作
圧力を常圧以下とすることを特徴とするテレフタル酸の
回収方法。2. The recovery method according to claim 1, wherein the same amount or more of diluting water as the terephthalic acid slurry held in the crystallization tank one stage before the last stage is fed into the crystallization tank. A method for recovering terephthalic acid, wherein the operating pressure is equal to or lower than normal pressure.
程の後流に常圧以下で操作される洗浄装置付きの固液分
離装置を１段のみ設置することを特徴とするテレフタル
酸の回収方法。3. The recovery method according to claim 2, wherein only one stage of a solid-liquid separation device equipped with a washing device operated at normal pressure or lower is installed downstream of the crystallization step. Collection method.
Priority Applications (5)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP03086398A JP3648372B2 (en) | 1998-02-13 | 1998-02-13 | Recovery method of terephthalic acid |
| PCT/JP1998/004413 WO1999041225A1 (en) | 1998-02-13 | 1998-09-30 | Method and apparatus for recovering terephthalic acid |
| KR1020007008682A KR100355334B1 (en) | 1998-02-13 | 1998-09-30 | Method and apparatus for recovering terephthalic acid |
| CN98813576A CN1124252C (en) | 1998-02-13 | 1998-09-30 | Method and apparatus for recovering terephthalic acid |
| TW088101253A TW577873B (en) | 1998-02-13 | 1999-01-27 | Method for recovering terephthalic acid |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP03086398A JP3648372B2 (en) | 1998-02-13 | 1998-02-13 | Recovery method of terephthalic acid |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH11228492A true JPH11228492A (en) | 1999-08-24 |
| JP3648372B2 JP3648372B2 (en) | 2005-05-18 |
Family
ID=12315575
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP03086398A Expired - Lifetime JP3648372B2 (en) | 1998-02-13 | 1998-02-13 | Recovery method of terephthalic acid |
Country Status (5)
| Country | Link |
|---|---|
| JP (1) | JP3648372B2 (en) |
| KR (1) | KR100355334B1 (en) |
| CN (1) | CN1124252C (en) |
| TW (1) | TW577873B (en) |
| WO (1) | WO1999041225A1 (en) |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2005225916A (en) * | 2004-02-10 | 2005-08-25 | Fuji Xerox Co Ltd | Method for producing organic functional material, organic functional material and organic electroluminescent element using the same |
| WO2005115956A1 (en) * | 2004-05-28 | 2005-12-08 | Mitsubishi Chemical Corporation | Process for producing high-purity terephthalic acid |
| JP2006096710A (en) * | 2004-09-30 | 2006-04-13 | Hitachi Ltd | Purification method of terephthalic acid |
| JP2008524198A (en) * | 2004-12-15 | 2008-07-10 | サウディ ベーシック インダストリーズ コーポレイション | Method for preparing high purity terephthalic acid |
| WO2018051775A1 (en) * | 2016-09-14 | 2018-03-22 | 三菱瓦斯化学株式会社 | Method for producing high-purity terephthalic acid |
| JP2019534854A (en) * | 2017-03-22 | 2019-12-05 | 天華化工機械及自動化研究設計院有限公司Ｔｉａｎｈｕａ Ｉｎｓｔｉｔｕｔｅ Ｏｆ Ｃｈｅｍｉｃａｌ Ｍａｃｈｉｎｅｒｙ Ａｎｄ Ａｕｔｏｍａｔｉｏｎ Ｃｏ．，Ｌｔｄ． | Recovery and use of PTA purification unit mother liquor |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR100883288B1 (en) * | 2004-05-28 | 2009-02-11 | 미쓰비시 가가꾸 가부시키가이샤 | Process for producing high-purity terephthalic acid |
| WO2008105087A1 (en) * | 2007-02-28 | 2008-09-04 | Hitachi Plant Technologies, Ltd. | Process for producing crude aromatic dicarboxylic acid to be fed to hydrogenation purification |
| CN101624343B (en) * | 2009-08-13 | 2012-12-19 | 中国纺织工业设计院 | Hydrogen recycling method and device of refining unit of pure terephthalic acid device |
| CN112774579B (en) * | 2020-12-28 | 2023-05-30 | 南京延长反应技术研究院有限公司 | Intelligent micro-interface reaction system and method for hydrofining of crude terephthalic acid |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP3612724B2 (en) * | 1994-02-03 | 2005-01-19 | 三菱化学株式会社 | Method for producing terephthalic acid with excellent slurry characteristics |
| JPH08208561A (en) * | 1994-11-16 | 1996-08-13 | Mitsubishi Chem Corp | Production of terephthalic acid |
| JPH1087555A (en) * | 1996-09-17 | 1998-04-07 | Hitachi Ltd | Recovery of terephthalic acid |
-
1998
- 1998-02-13 JP JP03086398A patent/JP3648372B2/en not_active Expired - Lifetime
- 1998-09-30 CN CN98813576A patent/CN1124252C/en not_active Expired - Lifetime
- 1998-09-30 KR KR1020007008682A patent/KR100355334B1/en not_active IP Right Cessation
- 1998-09-30 WO PCT/JP1998/004413 patent/WO1999041225A1/en active IP Right Grant
-
1999
- 1999-01-27 TW TW088101253A patent/TW577873B/en not_active IP Right Cessation
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2005225916A (en) * | 2004-02-10 | 2005-08-25 | Fuji Xerox Co Ltd | Method for producing organic functional material, organic functional material and organic electroluminescent element using the same |
| WO2005115956A1 (en) * | 2004-05-28 | 2005-12-08 | Mitsubishi Chemical Corporation | Process for producing high-purity terephthalic acid |
| JP2006096710A (en) * | 2004-09-30 | 2006-04-13 | Hitachi Ltd | Purification method of terephthalic acid |
| JP2008524198A (en) * | 2004-12-15 | 2008-07-10 | サウディ ベーシック インダストリーズ コーポレイション | Method for preparing high purity terephthalic acid |
| JP4861334B2 (en) * | 2004-12-15 | 2012-01-25 | サウディ ベーシック インダストリーズ コーポレイション | Method for preparing high purity terephthalic acid |
| WO2018051775A1 (en) * | 2016-09-14 | 2018-03-22 | 三菱瓦斯化学株式会社 | Method for producing high-purity terephthalic acid |
| EP3514136A4 (en) * | 2016-09-14 | 2020-04-22 | Mitsubishi Gas Chemical Company, Inc. | Method for producing high-purity terephthalic acid |
| US10683253B2 (en) | 2016-09-14 | 2020-06-16 | Mitsubishi Gas Chemical Company, Inc. | Method for producing high-purity terephthalic acid |
| JP2019534854A (en) * | 2017-03-22 | 2019-12-05 | 天華化工機械及自動化研究設計院有限公司Ｔｉａｎｈｕａ Ｉｎｓｔｉｔｕｔｅ Ｏｆ Ｃｈｅｍｉｃａｌ Ｍａｃｈｉｎｅｒｙ Ａｎｄ Ａｕｔｏｍａｔｉｏｎ Ｃｏ．，Ｌｔｄ． | Recovery and use of PTA purification unit mother liquor |
Also Published As
| Publication number | Publication date |
|---|---|
| JP3648372B2 (en) | 2005-05-18 |
| WO1999041225A1 (en) | 1999-08-19 |
| CN1284940A (en) | 2001-02-21 |
| CN1124252C (en) | 2003-10-15 |
| KR20010040788A (en) | 2001-05-15 |
| KR100355334B1 (en) | 2002-10-12 |
| TW577873B (en) | 2004-03-01 |
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