JPH08176064A - Preparation of aqueous slurry of terephthalic acid - Google Patents
Preparation of aqueous slurry of terephthalic acidInfo
- Publication number
- JPH08176064A JPH08176064A JP6315019A JP31501994A JPH08176064A JP H08176064 A JPH08176064 A JP H08176064A JP 6315019 A JP6315019 A JP 6315019A JP 31501994 A JP31501994 A JP 31501994A JP H08176064 A JPH08176064 A JP H08176064A
- Authority
- JP
- Japan
- Prior art keywords
- acetic acid
- terephthalic acid
- slurry
- water
- ester
- 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
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P20/00—Technologies relating to chemical industry
- Y02P20/50—Improvements relating to the production of bulk chemicals
- Y02P20/52—Improvements relating to the production of bulk chemicals using catalysts, e.g. selective catalysts
Landscapes
- Low-Molecular Organic Synthesis Reactions Using Catalysts (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、パラキシレンを酢酸中
で液相酸化して製造したテレフタル酸の酢酸スラリ−の
分散媒を水に置換し、テレフタル酸の水スラリ−を調製
する方法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for preparing an aqueous slurry of terephthalic acid by substituting water for a dispersion medium of terephthalic acid slurry prepared by liquid-phase oxidation of paraxylene in acetic acid. .
【０００２】[0002]
【従来の技術】テレフタル酸は、通常、パラキシレンを
酢酸中、コバルト、マンガン及び臭素などを含む触媒の
存在下、分子状酸素と反応させる、いわゆるＳＤ法によ
り製造されている。これにより得られた反応混合物のテ
レフタル酸の酢酸スラリ−より、粗テレフタル酸を晶析
分離する。この粗テレフタル酸中には、不純物として４
−カルボキシベンズアルデヒド（以下「４ＣＢＡ」とい
う）が重量基準で通常１００〜１００００ｐｐｍ含まれ
ているので、さらに、これを還元精製することが多い。BACKGROUND OF THE INVENTION Terephthalic acid is usually produced by a so-called SD method in which paraxylene is reacted with molecular oxygen in acetic acid in the presence of a catalyst containing cobalt, manganese, bromine and the like. Crude terephthalic acid is separated by crystallization from the acetic acid slurry of terephthalic acid in the reaction mixture thus obtained. In this crude terephthalic acid, impurities of 4
-Carboxybenzaldehyde (hereinafter referred to as "4CBA") is usually contained in an amount of 100 to 10,000 ppm on a weight basis, and therefore it is often reduced and purified.
【０００３】この還元精製に際し、酢酸の残存する粗テ
レフタル酸は、通常、酢酸を除去して回収するために充
分に乾燥される。次に、乾燥した粗テレフタル酸を水に
分散させスラリ−化し、加圧・加熱して完全に溶解した
後、高圧・高温下で、一般に、水素の存在下で白金族金
属触媒と接触させて還元精製し、この後、晶析により精
製テレフタル酸の結晶を得る方法が採用されている。こ
の方法は、粗テレフタル酸の乾燥、貯蔵及び再スラリ−
化に設備が必要であるので製造コスト中における設備コ
ストが高くなるうえ、操作として煩雑であるという問題
がある。In this reduction and purification, the crude terephthalic acid with acetic acid remaining is usually sufficiently dried to remove acetic acid and recover it. Next, the dried crude terephthalic acid is dispersed in water to form a slurry, which is pressed and heated to completely dissolve it, and then contacted with a platinum group metal catalyst under high pressure and high temperature, generally in the presence of hydrogen. A method has been adopted in which purification is carried out by reduction and then crystals of purified terephthalic acid are obtained by crystallization. This method is for drying, storing and reslurrying crude terephthalic acid.
Since there is a need for equipment to realize this, there is a problem that the equipment cost in the manufacturing cost is high and the operation is complicated.
【０００４】そこで、テレフタル酸の酢酸スラリ−の分
散媒を水に置換するための改良方法がいくつか提案され
ている。例えば、特開平１−１６０９４２号公報には、
多段塔の上部からテレフタル酸の酢酸スラリ−を導入
し、水を該塔下部から導入して、多段塔内に上昇流をを
生成させるとともにテレフタル酸粒子を沈降させ、該多
段塔の上部より酢酸を、下部からテレフタル酸の水スラ
リ−を取り出す方法が提案されている。この置換方法で
は塔内でのテレフタル酸粒子の沈降に依存する性質上、
操作条件の設定やスケ−ルアップが容易でない。また、
かなりの量の水と酢酸の混合が避けられず、該混合液の
分離コストが大きくなる。Therefore, several improved methods have been proposed for substituting water for the dispersion medium of terephthalic acid acetate slurry. For example, JP-A-1-160942 discloses
An acetic acid slurry of terephthalic acid was introduced from the upper part of the multi-stage column, water was introduced from the lower part of the column to generate an upflow in the multi-stage column, and terephthalic acid particles were precipitated, and acetic acid was introduced from the upper part of the multi-stage column. A method of taking out a water slurry of terephthalic acid from the bottom is proposed. In this replacement method, due to the property that depends on the sedimentation of terephthalic acid particles in the tower,
It is not easy to set operating conditions and scale up. Also,
Mixing a considerable amount of water and acetic acid is unavoidable, which increases the separation cost of the mixed solution.
【０００５】また、テレフタル酸の酢酸スラリ−をフィ
ルタ−バンドあるいはフィルタ−セルに導入し、水で向
流多段洗浄して水スラリ−に置換する方法も提案されて
いる（特開平５−６５２４６号公報、特表平６−５０２
６５３号公報など）。これらの方法ではいずれも乾燥工
程を省略するという利点があるが、やはり大量の水と酢
酸の混合液が発生することになるので、該混合液の分離
コストが非常に大きくなることが懸念される。Further, a method has been proposed in which an acetic acid slurry of terephthalic acid is introduced into a filter band or a filter cell, and is subjected to multi-stage countercurrent washing with water to replace it with water slurry (Japanese Patent Laid-Open No. 5-65246). Gazette, Tokuhyo Hira 6-502
653 publication). All of these methods have the advantage of omitting the drying step, but since a large amount of a mixed solution of water and acetic acid is also generated, there is a concern that the separation cost of the mixed solution will become very large. .
【０００６】[0006]
【発明が解決しようとする課題】本発明の目的は、粗テ
レフタル酸の乾燥、貯蔵、水スラリ−調製のプロセスに
代わる簡便で効率的な改良方法であって、かつ、液置換
にかかる酢酸と水の混合を抑えて分離経費を抑制するこ
とができる経済的なプロセスを構築することにある。The object of the present invention is to provide a simple and efficient method for replacing crude terephthalic acid by drying, storage and water slurry preparation processes, and to obtain acetic acid for liquid replacement. It is to build an economical process that can suppress the mixing of water and the cost of separation.
【０００７】[0007]
【課題を解決するための手段】本発明者等は上記課題に
鑑み、鋭意検討を行った結果、晶析分離したテレフタル
酸結晶を酢酸エステルで洗浄する工程を含む溶媒置換の
方法を採用することによりこの課題が達成できることを
見いだし、本発明に到達した。すなわち、本発明は、パ
ラキシレンを酢酸溶媒中、触媒の存在下、分子状酸素で
液相酸化してテレフタル酸の酢酸スラリ−を得、該酢酸
スラリ−よりテレフタル酸結晶を分離し、該酢酸含有テ
レフタル酸結晶を酢酸エステルで洗浄し、次いで水を混
合することを特徴とするテレフタル酸水スラリ−の調製
方法に存する。Means for Solving the Problems In view of the above problems, the present inventors have conducted diligent studies, and as a result, have adopted a method of solvent replacement including a step of washing terephthalic acid crystals separated by crystallization with acetate ester. As a result, they have found that this problem can be achieved, and have reached the present invention. That is, according to the present invention, para-xylene is subjected to liquid phase oxidation with molecular oxygen in an acetic acid solvent in the presence of a catalyst to obtain an acetic acid slurry of terephthalic acid, and a terephthalic acid crystal is separated from the acetic acid slurry, and the acetic acid is separated from the acetic acid slurry. A method for preparing a terephthalic acid water slurry, which comprises washing the contained terephthalic acid crystals with acetic acid ester and then mixing with water.
【０００８】以下、本発明を詳細に説明する。パラキシ
レンの酸化反応としては、パラキシレンを酢酸溶媒中、
触媒の存在下、分子状酸素で液相酸化させる方法が採用
される。触媒としては、通常、遷移金属化合物と臭素化
合物の混合物を使用する。遷移金属化合物としては、マ
ンガン、コバルト、鉄、ニッケル、クロム等の遷移金属
の臭素塩、安息香酸塩、ナフテン酸塩、酢酸塩等のカル
ボン酸塩、アセチルアセトナート等が、また、臭素化合
物としては、マンガン、コバルト、鉄、ニッケル、クロ
ム等の臭素塩、臭化水素酸、臭化ナトリウム、臭化アン
モニウム、ジブロモエチレン、テトラブロモエタン等が
用いられている。なお、遷移金属の臭素塩は、遷移金属
化合物成分と臭素化合物成分とを兼ねることができる。
また、分子状酸素としては、純酸素、空気、純酸素と不
活性ガスとの混合物等が用いられる。The present invention will be described in detail below. As the oxidation reaction of para-xylene, para-xylene in acetic acid solvent,
A method of liquid-phase oxidation with molecular oxygen in the presence of a catalyst is adopted. As the catalyst, a mixture of a transition metal compound and a bromine compound is usually used. Examples of the transition metal compound include manganese, cobalt, iron, nickel, bromine salts of transition metals such as chromium, benzoate, naphthenate, carboxylates such as acetate, acetylacetonate, and the like, and also as a bromine compound. Are used, for example, bromine salts of manganese, cobalt, iron, nickel, chromium, hydrobromic acid, sodium bromide, ammonium bromide, dibromoethylene, tetrabromoethane and the like. The bromine salt of the transition metal can serve both as the transition metal compound component and the bromine compound component.
Further, as the molecular oxygen, pure oxygen, air, a mixture of pure oxygen and an inert gas, or the like is used.
【０００９】原料パラキシレンは１重量部に対し、溶媒
である酢酸は通常１〜１０重量部用いられ、酢酸中には
約３０重量％までの水分を含んでいてもよい。また、触
媒としてコバルト化合物及び／又はマンガン化合物と、
臭素化合物とが用いられるときは、これらの化合物は、
溶媒に対して、通常コバルト原子が１０〜５０００重量
ｐｐｍ、マンガン原子が１０〜５０００重量ｐｐｍ、臭
素原子が１０〜１００００重量ｐｐｍとなるように用い
られる。また、酸化反応器に供給する分子状酸素は、通
常、パラキシレン１モルに対して酸素として３〜２０モ
ルの割合となるように用いられる。そして、反応条件と
しては通常、１５０〜２３０℃の温度、２〜１００気圧
の圧力で行う。また、以上の反応条件を適宜変更し、段
階的に酸化反応を完結させてもよい。The starting material paraxylene is used in an amount of 1 to 10 parts by weight with respect to 1 part by weight of paraxylene, and the acetic acid may contain up to about 30% by weight of water. Further, a cobalt compound and / or a manganese compound as a catalyst,
When a bromine compound is used, these compounds are
It is usually used so that the cobalt atom content is 10 to 5000 weight ppm, the manganese atom content is 10 to 5000 weight ppm, and the bromine atom content is 10 to 10000 weight ppm with respect to the solvent. The molecular oxygen supplied to the oxidation reactor is usually used in a proportion of 3 to 20 mol of oxygen with respect to 1 mol of paraxylene. The reaction conditions are usually 150 to 230 ° C. and 2 to 100 atm. Further, the above reaction conditions may be appropriately changed to complete the oxidation reaction stepwise.
【００１０】以上の方法により得られた反応混合物であ
るテレフタル酸の酢酸スラリ−より、テレフタル酸を晶
析分離する。テレフタル酸の酢酸スラリ−を、通常２０
０〜５０℃、好ましくは１５０〜８０℃まで冷却し、テ
レフタル酸を晶析し、更に固液分離を行い、テレフタル
酸を結晶として回収する。固液分離は遠心分離、ろ過等
の公知の手段を採用すればよく、遠心沈降器、遠心ろ過
器、加圧ろ過器、真空ろ過器などの分離機器が使用され
る。The terephthalic acid is crystallized and separated from the acetic acid slurry of terephthalic acid, which is the reaction mixture obtained by the above method. Terephthalic acid slurry of acetic acid is usually 20
The mixture is cooled to 0 to 50 ° C., preferably 150 to 80 ° C., terephthalic acid is crystallized, and solid-liquid separation is performed to recover terephthalic acid as crystals. For solid-liquid separation, well-known means such as centrifugation and filtration may be adopted, and a separating device such as a centrifugal settler, a centrifugal filter, a pressure filter and a vacuum filter is used.
【００１１】なお、結晶分離後の母液の主成分は酢酸と
触媒成分であり、通常はその他の成分としてはテレフタ
ル酸と酸化中間体およびその他の酸化副生物をわずかに
含むのみであるので、母液の通常１０〜９０重量％を反
応系に循環させることが望ましい。また、反応系に循環
させない残りについては、蒸留により酢酸を回収し、蒸
留残渣からは触媒などの有効成分を回収することができ
る。The main components of the mother liquor after crystal separation are acetic acid and catalyst components, and the other components usually contain only a small amount of terephthalic acid, oxidation intermediates and other oxidation by-products. It is usually desirable to circulate 10 to 90% by weight of the above in the reaction system. In addition, acetic acid can be recovered by distillation from the remainder not circulated in the reaction system, and effective components such as a catalyst can be recovered from the distillation residue.
【００１２】また、テレフタル酸結晶は、必要に応じて
酢酸で洗浄してもよく、この酢酸洗浄液は上記の母液と
併せて反応系に循環させることができる。次に、本発明
においては、上記のように酢酸スラリ−より分離回収し
た酢酸含有テレフタル酸結晶を酢酸エステルで洗浄す
る。通常、常温から１３０℃で常圧または加圧の条件
下、酢酸が付着しているテレフタル酸結晶に酢酸エステ
ルを加えて洗浄、分離する方法を１回以上、好ましくは
２〜４回程度の複数回行う。洗浄方法は特に限定はない
が、通常、置換洗浄やスラリー化によるケーク洗浄が行
われる。置換洗浄ではテレフタル酸結晶であるろ過ケー
ク上に酢酸エステルを振りかけ、あるいはケークを覆う
液溜めを形成させ、次いで酢酸エステルを圧入し透過さ
せてケーク中の酢酸を除去する。また、洗浄効率を高め
るために、必要に応じてスラリ−化洗浄を行ってもよ
い。この場合、ケークの分離装置において、ケークに酢
酸エステルを加えて撹拌混合してスラリー化してもよい
し、別途、スラリー化のための撹拌槽を設けて洗浄を行
い、これを再度ろ過分離してもよい。以上の洗浄、分離
のための装置は特に制限はないが、加圧ろ過器、真空ろ
過器を用いる方法が好ましく、加圧ヌッチェ、ベルトフ
ィルタ−、回転円筒型ろ過器などの機器を使用すること
により、ろ過、洗浄、脱液、ケ−ク除去の工程を連続的
に効率よく実施することができる。The terephthalic acid crystals may be washed with acetic acid if necessary, and this acetic acid washing liquid can be circulated to the reaction system together with the above mother liquor. Next, in the present invention, the acetic acid-containing terephthalic acid crystals separated and recovered from the acetic acid slurry as described above are washed with acetic acid ester. Usually, at room temperature to 130 ° C. under normal pressure or pressure, a method of adding acetyl ester to terephthalic acid crystals to which acetic acid adheres and washing and separating is performed once or more, preferably about 2 to 4 times. Do it once. The washing method is not particularly limited, but generally, substitution washing or cake washing by slurrying is performed. In the displacement washing, acetic acid ester is sprinkled on a filter cake which is a terephthalic acid crystal, or a liquid reservoir is formed to cover the cake, and then acetic acid ester is press-fitted and permeated to remove acetic acid in the cake. Further, in order to enhance the cleaning efficiency, slurry cleaning may be performed as necessary. In this case, in the cake separator, the acetic acid ester may be added to the cake and mixed by stirring to form a slurry, or separately, a stirring tank for slurry formation may be provided for washing, and the mixture may be filtered and separated again. Good. The device for washing and separating is not particularly limited, but a method using a pressure filter or a vacuum filter is preferable, and a device such as a pressure nutsche, a belt filter or a rotary cylindrical filter is used. Thus, the steps of filtration, washing, deliquoring, and cake removal can be carried out continuously and efficiently.
【００１３】酢酸エステルの種類は、パラキシレンの酸
化あるいは粗テレフタル酸の還元精製の反応に悪影響が
ない限り特に限定はないが、沸点や溶解性などにおいて
酢酸あるいは水との分離が容易なものが望ましく、例え
ば、炭素数１〜８、好ましくは１〜４のアルキル基を有
する酢酸エステルの酢酸メチル、酢酸エチル、酢酸ブチ
ル等が例示される。The type of acetic acid ester is not particularly limited as long as it does not adversely affect the reaction of the oxidation of paraxylene or the reduction and purification of crude terephthalic acid, but those which are easily separated from acetic acid or water in terms of boiling point and solubility. Desirably, for example, methyl acetate, ethyl acetate, butyl acetate and the like of acetic acid ester having an alkyl group having 1 to 8 carbon atoms, preferably 1 to 4 carbon atoms are exemplified.
【００１４】洗浄に用いる酢酸エステルの総量は、テレ
フタル酸に対して通常０．１〜５重量倍量、好ましくは
０．２〜２重量倍量であり、繰り返し洗浄する場合は、
１回の洗浄に用いる酢酸エステルの量は、テレフタル酸
に対して通常０．０５〜３重量倍量、好ましくは０．１
〜１重量倍量である。また、繰り返し洗浄する場合は、
酢酸エステルの洗浄液の総量を増やさないため向流洗浄
することが望ましい。The total amount of acetic acid ester used for washing is usually 0.1 to 5 times by weight, preferably 0.2 to 2 times by weight, with respect to terephthalic acid.
The amount of acetic ester used for one washing is usually 0.05 to 3 times by weight, preferably 0.1 to terephthalic acid.
~ 1 times the weight amount. Also, when repeatedly washing,
Countercurrent washing is desirable because it does not increase the total amount of acetate washing solution.
【００１５】酢酸エステルで洗浄した液中には、酢酸エ
ステルの他に、酸化反応の溶媒である酢酸、及び、若干
のテレフタル酸などの有効成分が含まれている。また、
酢酸エステル自体はパラキシレンの酸化反応系では分解
して酢酸を生成するものであるので、また、酢酸エステ
ルで洗浄した液を反応系に循環して使用してもよい。ま
た、酢酸エステルで洗浄した液を蒸留して酢酸エステル
の少なくとも一部を分離回収し、該酢酸エステルを酢酸
含有テレフタル酸結晶の洗浄に再使用することができ
る。更に、酢酸エステルの少なくとも一部を分離した残
液は、反応系に循環すればよい。The solution washed with acetic acid ester contains, in addition to acetic acid ester, acetic acid which is a solvent for the oxidation reaction, and some active ingredients such as terephthalic acid. Also,
Since the acetic acid ester itself is decomposed in the para-xylene oxidation reaction system to generate acetic acid, a solution washed with acetic acid ester may be circulated to the reaction system for use. Further, the solution washed with acetic acid ester can be distilled to separate and collect at least a part of the acetic acid ester, and the acetic acid ester can be reused for washing the acetic acid-containing terephthalic acid crystals. Further, the residual liquid obtained by separating at least a part of the acetic acid ester may be circulated to the reaction system.
【００１６】次に、以上のように酢酸エステルで洗浄し
たテレフタル酸結晶は、酢酸の洗浄に使用した酢酸エス
テルの大部分を分離して、水を混合することによりテレ
フタル酸の水スラリ−を調製する。これに用いる水の量
は、前記のテレフタル酸に対する酢酸エステルの使用量
程度に対応している。水を混合する方法は特に制限はな
く、酢酸エステルが付着しているテレフタル酸結晶に、
単に所定量の水を混合して水スラリー化を得る方法でも
よいし、水を加えて置換洗浄あるいはスラリー洗浄した
後に所望量の水を加えて最終的な水スラリ−を得る方法
でもよい。Next, from the terephthalic acid crystals washed with the acetic acid ester as described above, most of the acetic acid ester used for washing the acetic acid is separated and mixed with water to prepare a water slurry of terephthalic acid. To do. The amount of water used for this corresponds to the amount of acetic acid ester used for terephthalic acid. The method of mixing water is not particularly limited, and to the terephthalic acid crystal to which the acetic acid ester is attached,
A method of simply mixing a predetermined amount of water to obtain a water slurry, or a method of adding water to carry out displacement washing or slurry washing and then adding a desired amount of water to obtain a final water slurry may be used.
【００１７】酢酸エステルが付着しているテレフタル酸
結晶に水を加えてスラリー化して洗浄する方法によれ
ば、酢酸エステルの洗浄効率が特に高く、酢酸エステル
をほぼ完全に洗浄除去することが可能である。以上のよ
うな水スラリーへの置換操作は１回だけでもよいが、酢
酸エステルの洗浄効率を高くするために２〜４回程度の
複数回行ってもよい。また、洗浄水は、回収して再利用
することができる。According to the method in which water is added to the terephthalic acid crystal to which the acetic acid ester is attached to form a slurry and the slurry is washed, the efficiency of cleaning the acetic acid ester is particularly high, and the acetic acid ester can be almost completely washed and removed. is there. The replacement operation with the water slurry as described above may be carried out only once, but may be carried out a plurality of times such as about 2 to 4 times in order to improve the washing efficiency of the acetate ester. Further, the wash water can be collected and reused.
【００１８】得られた水スラリー中にいくらかの酢酸エ
ステルが含まれる場合がありうるが、この酢酸エステル
の分離は容易である。スラリーを静置した際に相分離す
るようであれば、上相となる酢酸エステル相を分離すれ
ばよく、あるいは、水洗浄液を加熱して酢酸エステルを
蒸発回収することもできる。分離した酢酸エステルは、
反応原料あるいは前記のテレフタル酸結晶の洗浄用とし
て再利用できる。It is possible that some acetic acid ester may be contained in the resulting water slurry, but this acetic acid ester is easy to separate. If phase separation occurs when the slurry is allowed to stand, the upper phase acetate ester phase may be separated, or the water washing liquid may be heated to recover the acetate ester by evaporation. The separated acetate ester is
It can be reused for washing the reaction raw material or the terephthalic acid crystal.
【００１９】以上のようにテレフタル酸結晶に付着した
酢酸エステルを水で置換した結果、還元精製工程にその
まま供することができるテレフタル酸の水スラリ−が調
製できたことになる。なお、テレフタル酸結晶に付着し
た酢酸エステルは再利用できるという点ではできるだけ
回収できた方がよいが、以下に説明するような水スラリ
ーとしてテレフタル酸を還元精製する際において、水ス
ラリー中にある程度の酢酸エステルが含まれていても特
に支障はない。この場合、水スラリー中の酢酸エステル
の濃度は、テレフタル酸に対して通常１０％以下、好ま
しくは５％以下である。As described above, as a result of substituting water for the acetic acid ester attached to the terephthalic acid crystals, it is possible to prepare a water slurry of terephthalic acid that can be directly used in the reduction purification step. It should be noted that the acetic acid ester adhering to the terephthalic acid crystals should be recovered as much as possible in that it can be reused. However, when reducing and purifying terephthalic acid as a water slurry as described below, a certain amount of water ester is added to the water slurry. There is no particular problem even if the acetic acid ester is contained. In this case, the concentration of acetic acid ester in the water slurry is usually 10% or less, preferably 5% or less, based on terephthalic acid.
【００２０】このように分散媒を酢酸から水に置換した
粗テレフタル酸の水スラリーは、テレフタル酸の濃度
を、通常１〜６０重量％、好ましくは１０〜４０重量％
に調整して還元精製に供される。水スラリーを加圧・加
温して粗テレフタル酸を水に完全に溶解させ、該水溶液
を高圧・高温下、一般に水素の存在下で白金族金属と接
触させて還元精製する。テレフタル酸水溶液と水素ガス
とを反応器に供給し、通常２２０〜３２０℃、好ましく
は２６０〜３００℃の温度条件下で触媒と接触させる。
水素ガスはテレフタル酸水溶液１０００ｋｇに対し０．
０５〜１０Ｎｍ3、好ましくは０．１〜３Ｎｍ3 の割合
で供給すればよい。白金族金属を含む触媒としては、パ
ラジウム、ルテニウム、ロジウム、オスミウム、イリジ
ウム、白金等、又はこれらの金属酸化物が用いられる。
これらの金属又は金属酸化物はそのまま触媒として使用
することもできるが、テレフタル酸水溶液に不溶性の、
例えば、活性炭のごとき担体に担持させたものも使用さ
れる。このようにして還元精製処理したテレフタル酸の
熱水溶液は、次いで、通常２００〜７０℃まで冷却し、
テレフタル酸を晶析、固液分離した後、乾燥して高純度
のテレフタル酸を得る。The water slurry of crude terephthalic acid in which the dispersion medium is replaced with acetic acid in this way has a terephthalic acid concentration of usually 1 to 60% by weight, preferably 10 to 40% by weight.
It is adjusted to the above and supplied for reduction and purification. The water slurry is pressurized and heated to completely dissolve the crude terephthalic acid in water, and the aqueous solution is brought into contact with a platinum group metal in the presence of hydrogen at high pressure and high temperature to carry out reduction purification. An aqueous solution of terephthalic acid and hydrogen gas are supplied to the reactor and contacted with the catalyst under temperature conditions of usually 220 to 320 ° C, preferably 260 to 300 ° C.
Hydrogen gas is 0.1% for 1000 kg of terephthalic acid aqueous solution.
It may be supplied at a rate of 05 to 10 Nm 3 , preferably 0.1 to 3 Nm 3 . As the catalyst containing a platinum group metal, palladium, ruthenium, rhodium, osmium, iridium, platinum or the like, or a metal oxide thereof is used.
These metals or metal oxides can be used as a catalyst as they are, but are insoluble in an aqueous terephthalic acid solution,
For example, a carrier such as activated carbon supported on a carrier is also used. The hot aqueous solution of terephthalic acid thus reduced and purified is then usually cooled to 200 to 70 ° C.,
Crystallization of terephthalic acid, solid-liquid separation, and drying are performed to obtain high-purity terephthalic acid.
【００２１】[0021]
【実施例】以下に実施例により本発明をさらに具体的に
説明するが、本発明はその要旨を超えない限り以下の実
施例に限定されるものではない。The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to the following examples as long as the gist thereof is not exceeded.
【００２２】実施例１ 酢酸溶媒中、コバルト及びマンガン化合物及び臭素化合
物の存在下、分子状酸素によってパラキシレンを酸化し
て得られた粗テレフタル酸６０ｇと、１０重量％含水酢
酸１４０ｇからなるスラリーを室温にて、直径７０ｍｍ
のヌッチェ（５Ａ濾紙使用）を用いて吸引濾過分離を行
った。この際、分離されたテレフタル酸の付着酢酸量
が、テレフタル酸に対して８〜１０重量％になるように
条件を設定した。次いで、テレフタル酸に対して０．６
５重量倍の酢酸メチルを、ヌッチェのテレフタル酸のケ
ーキ層に振りかけ、前記酢酸の場合と同様に吸引濾過分
離することによる洗浄を２回行った。該分離後のケーキ
中の酢酸と酢酸メチルの含有量を分析した結果を表−１
に示す。次に、テレフタル酸に対して１．２重量倍の水
をヌッチェのテレフタル酸のケーキ層に振りかけ、前記
と同様に吸引濾過分離する操作を２回行った。該分離後
のケーキ中の酢酸と酢酸エステルの含有量を分析した結
果を表−１に示す。Example 1 A slurry of 60 g of crude terephthalic acid obtained by oxidizing paraxylene with molecular oxygen in the presence of cobalt and manganese compounds and bromine compounds in an acetic acid solvent and 140 g of acetic acid containing 10% by weight of water was prepared. 70 mm diameter at room temperature
Suction filtration separation was carried out using a Nutsche (using 5A filter paper). At this time, the conditions were set such that the amount of acetic acid attached to the separated terephthalic acid was 8 to 10% by weight with respect to terephthalic acid. Then 0.6 for terephthalic acid
Five times by weight of methyl acetate was sprinkled on the cake layer of Nutsche's terephthalic acid, and suction filtration separation was carried out in the same manner as in the case of the above acetic acid to perform washing twice. The results of analysis of the contents of acetic acid and methyl acetate in the cake after the separation are shown in Table-1.
Shown in Next, 1.2 times by weight of water relative to terephthalic acid was sprinkled on the cake layer of terephthalic acid in Nutsche, and the operation of suction filtration separation was performed twice as in the above. Table 1 shows the results of analyzing the contents of acetic acid and acetic acid ester in the cake after the separation.
【００２３】実施例２〜８ 実施例１において、酢酸エステルの種類、粗テレフタル
酸ケーキの酢酸含有量、あるいは酢酸エステルと水の使
用量、洗浄回数などを変更して試験した場合の結果を表
−１に示す。なお、実施例３と実施例８では、酢酸エス
テル洗浄後のケークに所定量の水を加えて混合してスラ
リー化した後で吸引濾過分離することにより洗浄を行っ
たものである。Examples 2 to 8 In Example 1, the results obtained by changing the type of acetic ester, the acetic acid content of the crude terephthalic acid cake, the amount of acetic ester and water used, the number of washings, etc. -1. In addition, in Example 3 and Example 8, a predetermined amount of water was added to the cake after washing with the acetic acid ester to form a slurry, which was then washed by performing suction filtration separation.
【００２４】[0024]
【表１】 [Table 1]
【００２５】[0025]
【発明の効果】本発明は、パラキシレンを酢酸中で液相
酸化して製造したテレフタル酸の酢酸スラリ−につき、
テレフタル酸の乾燥、貯蔵、水スラリ−の複雑な工程を
経ることなく、簡便で経済的に水に置換することができ
る。また、この溶媒置換に伴う水への酢酸の混入量が極
めて少ないので、テレフタル酸の製造コストの上におい
ても大きなメリットがある。The present invention relates to an acetic acid slurry of terephthalic acid produced by liquid phase oxidation of paraxylene in acetic acid.
The terephthalic acid can be simply and economically replaced with water without the complicated steps of drying, storing, and water slurry. Further, since the amount of acetic acid mixed in water due to the solvent replacement is extremely small, there is a great merit in terms of the production cost of terephthalic acid.
Claims (7)
下、分子状酸素で液相酸化してテレフタル酸の酢酸スラ
リ−を得、該酢酸スラリ−よりテレフタル酸結晶を分離
し、該酢酸含有テレフタル酸結晶を酢酸エステルで洗浄
し、次いで水を混合することを特徴とするテレフタル酸
水スラリ−の調製方法。1. Paraxylene is subjected to liquid phase oxidation with molecular oxygen in the presence of a catalyst in an acetic acid solvent to obtain a slurry of terephthalic acid in the form of acetic acid. A method for preparing a terephthalic acid water slurry, which comprises washing terephthalic acid crystals with an acetate ester and then mixing with water.
下、分子状酸素で液相酸化してテレフタル酸の酢酸スラ
リ−を得、該酢酸スラリ−よりテレフタル酸結晶を分離
し、該酢酸含有テレフタル酸結晶を酢酸エステルで洗浄
し、次いで水を混合してスラリー化し、該水スラリー中
の残存酢酸エステルを相分離及び／又は加熱蒸発により
除去することを特徴とするテレフタル酸水スラリ−の調
製方法。2. Paraxylene is subjected to liquid phase oxidation with molecular oxygen in the presence of a catalyst in an acetic acid solvent to obtain a slurry of terephthalic acid in the form of acetic acid, and terephthalic acid crystals are separated from the acetic acid slurry and the acetic acid-containing solution is contained. Preparation of terephthalic acid water slurry, characterized in that crystals of terephthalic acid are washed with acetic acid ester, then water is mixed to form a slurry, and residual acetic acid ester in the water slurry is removed by phase separation and / or heat evaporation. Method.
酸エステルを分離回収し、該酢酸エステルを酢酸含有テ
レフタル酸結晶の洗浄に再使用することを特徴とする請
求項１又は２の方法。3. The method according to claim 1, wherein the solution washed with the acetic acid ester is distilled to separate and recover the acetic acid ester, and the acetic acid ester is reused for cleaning the acetic acid-containing terephthalic acid crystals.
ルで置換洗浄することを特徴とする請求項１ないし３の
いずれかの方法。4. The method according to claim 1, wherein the acetic acid-containing terephthalic acid crystal is replaced by washing with acetic acid ester.
ルでスラリー洗浄することを特徴とする請求項１ないし
３のいずれかの方法。5. The method according to claim 1, wherein the acetic acid-containing terephthalic acid crystal is slurry-washed with an acetic acid ester.
晶を水で置換洗浄し、次いで水を混合することによりテ
レフタル酸水スラリ−を得ることを特徴とする請求項１
ないし５のいずれかの方法。6. A terephthalic acid water slurry is obtained by displacing and washing the terephthalic acid crystals washed with acetic acid ester and then mixing with water.
5 to any one of the methods.
晶を水でスラリー洗浄し、次いで水を混合することによ
りテレフタル酸水スラリ−を得ることを特徴とする請求
項１ないし５のいずれかの方法。7. The method according to claim 1, wherein the terephthalic acid crystal washed with acetic ester is slurry-washed with water, and then water is mixed to obtain a terephthalic acid water slurry.
Priority Applications (6)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP31501994A JP3484792B2 (en) | 1994-12-19 | 1994-12-19 | Preparation method of terephthalic acid aqueous slurry |
| TW084111204A TW299318B (en) | 1994-11-15 | 1995-10-23 | |
| GB9522138A GB2295149B (en) | 1994-11-15 | 1995-10-30 | Process for preparing an aqueous slurry of terephthalic acid |
| US08/550,935 US5557009A (en) | 1994-11-15 | 1995-10-31 | Process for preparing an aqueous slurry of terephthalic acid |
| KR1019950041322A KR960017615A (en) | 1994-11-15 | 1995-11-14 | Preparation method of aqueous terephthalic acid slurry |
| CN95119339A CN1129693A (en) | 1994-11-15 | 1995-11-15 | Preparation of aqueous paste of terephthalic acid |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP31501994A JP3484792B2 (en) | 1994-12-19 | 1994-12-19 | Preparation method of terephthalic acid aqueous slurry |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH08176064A true JPH08176064A (en) | 1996-07-09 |
| JP3484792B2 JP3484792B2 (en) | 2004-01-06 |
Family
ID=18060447
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP31501994A Expired - Lifetime JP3484792B2 (en) | 1994-11-15 | 1994-12-19 | Preparation method of terephthalic acid aqueous slurry |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3484792B2 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1998018750A1 (en) * | 1996-10-30 | 1998-05-07 | Mitsui Chemicals, Inc. | Process for preparing aromatic dicarboxylic acids |
| JP2003210970A (en) * | 2002-01-17 | 2003-07-29 | Tokuyama Corp | Method for producing colloidal fine particle slurry |
-
1994
- 1994-12-19 JP JP31501994A patent/JP3484792B2/en not_active Expired - Lifetime
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1998018750A1 (en) * | 1996-10-30 | 1998-05-07 | Mitsui Chemicals, Inc. | Process for preparing aromatic dicarboxylic acids |
| US5925786A (en) * | 1996-10-30 | 1999-07-20 | Mitsui Chemicals, Inc. | Process for producing aromatic dicarboxylic acid |
| JP2003210970A (en) * | 2002-01-17 | 2003-07-29 | Tokuyama Corp | Method for producing colloidal fine particle slurry |
Also Published As
| Publication number | Publication date |
|---|---|
| JP3484792B2 (en) | 2004-01-06 |
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