JPH06321855A - Production of high-purity terephthalic acid - Google Patents
Production of high-purity terephthalic acidInfo
- Publication number
- JPH06321855A JPH06321855A JP5111573A JP11157393A JPH06321855A JP H06321855 A JPH06321855 A JP H06321855A JP 5111573 A JP5111573 A JP 5111573A JP 11157393 A JP11157393 A JP 11157393A JP H06321855 A JPH06321855 A JP H06321855A
- Authority
- JP
- Japan
- Prior art keywords
- oxidation reactor
- terephthalic acid
- containing gas
- molecular oxygen
- supplied
- 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
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明はテレフタル酸の製造法に
関するものである。詳しくは酸化反応器に供給する分子
状酸素含有ガスの供給方法を改良して、高純度のテレフ
タル酸を製造する方法に関するものである。FIELD OF THE INVENTION The present invention relates to a method for producing terephthalic acid. More specifically, the present invention relates to a method for producing high-purity terephthalic acid by improving the method for supplying the molecular oxygen-containing gas to be supplied to the oxidation reactor.
【０００２】[0002]
【従来の技術】テレフタル酸はポリエステルの原料とし
て極めて重要な化合物である。テレフタル酸の製造法と
しては、パラキシレンを重金属及び臭素を含む触媒の存
在下に酢酸溶媒中で分子状酸素含有ガスで酸化する方法
が代表的なものであり、工業的に大規模に実施されてい
る。この方法では、撹拌槽型の酸化反応器に触媒を溶解
した酢酸溶媒を収容しておき、これにパラキシレンと分
子状酸素含有ガスとを連続的に供給する。パラキシレン
はテレフタル酸に酸化され、生成したテレフタル酸を含
む反応混合物は酸化反応器から抜出され、所望により更
に追酸化したのち析出しているテレフタル酸結晶を分離
回収する。結晶を分離した後の反応母液は、不純物の蓄
積を防ぐためその一部を系外に排出し、残余は酸化反応
器に循環する。燃焼及び系外への排出等により反応系か
ら失なわれる酢酸溶媒及び触媒は、新たな酢酸及び触媒
を系外から供給することにより補充され、系内の酢酸濃
度及び触媒濃度等は、常に一定の状態に保つようにす
る。2. Description of the Related Art Terephthalic acid is a very important compound as a raw material for polyester. A typical method for producing terephthalic acid is to oxidize para-xylene with a molecular oxygen-containing gas in an acetic acid solvent in the presence of a catalyst containing heavy metals and bromine, which is industrially carried out on a large scale. ing. In this method, an acetic acid solvent in which a catalyst is dissolved is stored in a stirring tank type oxidation reactor, and para-xylene and a molecular oxygen-containing gas are continuously supplied to the acetic acid solvent. Para-xylene is oxidized to terephthalic acid, and the reaction mixture containing the produced terephthalic acid is withdrawn from the oxidation reactor, and if necessary, after additional oxidation, the precipitated terephthalic acid crystals are separated and recovered. A part of the reaction mother liquor after separating the crystals is discharged out of the system to prevent accumulation of impurities, and the rest is circulated to the oxidation reactor. Acetic acid solvent and catalyst that are lost from the reaction system due to combustion and discharge to the outside of the system are replenished by supplying new acetic acid and catalyst from outside the system, and the acetic acid concentration and catalyst concentration inside the system are always constant. Try to keep the condition of.
【０００３】[0003]
【発明が解決しようとする課題】テレフタル酸の製造に
おいては、酸化反応器内の液相及びこれに導入される分
子状酸素含有ガスの混合・分散をよくすることが必要で
ある。特に分子状酸素含有ガスの分散が不均一で酸素の
供給不良な箇所ができると、その部分では酸化反応が十
分に進行しないだけでなく、着色不純物が増加して生成
するテレフタル酸の品質を大幅に低下させる。更に場合
によっては反応操作上種々の障害を引きおこすことすら
ある。従って本発明は高品質のテレフタル酸を製造する
方法を提供せんとするものである。In the production of terephthalic acid, it is necessary to improve the mixing and dispersion of the liquid phase in the oxidation reactor and the molecular oxygen-containing gas introduced therein. In particular, if there is a part where the molecular oxygen-containing gas is not uniformly dispersed and oxygen is not supplied well, not only the oxidation reaction does not proceed sufficiently at that part, but also the quality of terephthalic acid produced by the increase of colored impurities is greatly increased. Lower to. Further, in some cases, it may even cause various obstacles in the reaction operation. Accordingly, the present invention seeks to provide a method for producing high quality terephthalic acid.
【０００４】[0004]
【課題を解決するための手段】本発明者らは酸化反応器
内への分子状酸素含有ガスの供給態様と生成するテレフ
タル酸の品質との関係について検討した結果、酸化反応
器の内壁に設置されている邪魔板が分子状酸素含有ガス
の均一分散に大きな障害となっていること、及び各邪魔
板で区画された領域毎に分子状酸素含有ガスを供給する
ようにするとこの障害を克服し得ることを見出し、本発
明を達成した。The present inventors have investigated the relationship between the supply mode of the molecular oxygen-containing gas into the oxidation reactor and the quality of the terephthalic acid produced, and as a result, installed it on the inner wall of the oxidation reactor. The baffles that are installed are major obstacles to the uniform dispersion of the molecular oxygen-containing gas, and the supply of the molecular oxygen-containing gas to each of the regions partitioned by each baffle overcomes this obstacle. The present invention has been accomplished by finding that they can be obtained.
【０００５】本発明によれば、重金属と臭素を含む触媒
を溶解した酢酸溶媒が収容されており、且つ内壁上に複
数の邪魔板が縦方行に並設されている酸化反応器に、パ
ラキシレンと分子状酸素含有ガスとを連続的に供給して
パラキシレンを酸化するテレフタル酸の製造法におい
て、各邪魔板で区画された領域毎に分子状酸素含有ガス
を供給することにより高品質のテレフタル酸を製造する
ことができる。According to the present invention, an acetic acid solvent in which a catalyst containing a heavy metal and bromine is dissolved is accommodated, and a plurality of baffle plates are vertically arranged in parallel on an inner wall of an oxidation reactor. In a method for producing terephthalic acid in which xylene and a molecular oxygen-containing gas are continuously supplied to oxidize paraxylene, a high-quality molecular oxygen-containing gas is supplied to each region partitioned by each baffle plate. Terephthalic acid can be produced.
【０００６】本発明について更に詳細に説明するに、本
発明では内壁上に複数枚の邪魔板が縦方向に並設されて
いる酸化反応器を用いる。邪魔板の数は４〜８枚が好ま
しく、且つ内壁上に等間隔で設置されているのが好まし
い。邪魔板の幅、すなわち内壁からの突出長さは、撹拌
効果からして酸化反応器内径の１／１５以上である。し
かし幅が広すぎても撹拌効果の向上はないので、酸化反
応器内径の１／８〜１／１２が好ましい。To explain the present invention in more detail, the present invention uses an oxidation reactor in which a plurality of baffles are vertically arranged on an inner wall. The number of baffle plates is preferably 4 to 8, and it is preferable that the baffle plates are installed on the inner wall at equal intervals. The width of the baffle plate, that is, the protruding length from the inner wall is 1/15 or more of the inner diameter of the oxidation reactor due to the stirring effect. However, if the width is too wide, the stirring effect is not improved, so 1/8 to 1/12 of the inner diameter of the oxidation reactor is preferable.
【０００７】各邪魔板間、すなわち隣接する２枚の邪魔
板と内壁とで囲まれた部分では、上下方向への気・液の
移動は速やかに行なわれるが、邪魔板を越えての気・液
の移動は極めて遅い。本発明では邪魔板で区画された領
域毎に分子状酸素含有ガスを供給することにより、各領
域での酸素濃度を均一とし、以って局所的な酸素濃度不
足から生ずるテレフタル酸の品質低下を回避することが
できる。なお本発明において邪魔板で区画された領域と
は、邪魔板の先端を酸化反応器の中心軸まで延長したと
想定したときに隣接する邪魔板間に形成される、上方か
ら見て扇状の領域を指す。従って、本発明では酸化反応
器は、邪魔板の数だけの領域に区画されているものと見
做される。各領域への分子状酸素含有ガスの供給量は、
それぞれの領域の単位液量当りのガス量がほぼ等しくな
るような量、すなわち全供給量を領域数で除した値に対
し±２０％の範囲内にあるのが好ましい。各領域内にお
ける分子状酸素含有ガスの供給口は、酸化反応器の中心
軸と内壁を結ぶ直線上で、通常は中心軸から０．１〜
０．９Ｒ、好ましくは０．２〜０．８Ｒ（Ｒ：中心軸か
ら内壁までの距離）の位置に配置する。特に好ましく
は、中心軸と内壁を結ぶ直線上で酸化反応器に設置され
ている撹拌機の撹拌翼の先端の近傍、すなわち先端から
±０．１Ｒの範囲内に設置する。撹拌翼の先端は通常、
中心軸から０．２〜０．７Ｒの位置にあるが、この先端
から±０．１Ｒの位置にガス供給口があると、反応が極
めて良好に行なわれる。また、分子状酸素含有ガスの供
給位置は、液面から酸化反応器底部までの距離の２／３
より下方に位置させるのが好ましい。なお、主酸化と追
酸化とから成るプロセスの場合には、少くとも主酸化を
本発明に従って行なえばよい。Between the respective baffle plates, that is, in the part surrounded by the two adjacent baffle plates and the inner wall, the gas and liquid move quickly in the vertical direction, but the air and liquid passing over the baffle plates are increased. The movement of liquid is extremely slow. In the present invention, the molecular oxygen-containing gas is supplied to each of the regions divided by the baffle plate so that the oxygen concentration in each region is made uniform, thereby reducing the quality of terephthalic acid caused by the local lack of oxygen concentration. It can be avoided. In the present invention, the region partitioned by the baffle plate is a fan-shaped region formed from above between adjacent baffle plates when the tip of the baffle plate is assumed to extend to the central axis of the oxidation reactor. Refers to. Therefore, in the present invention, the oxidation reactor is regarded as being divided into as many regions as baffle plates. The supply amount of the molecular oxygen-containing gas to each region is
It is preferable that the amount is such that the gas amount per unit liquid amount in each region is substantially equal, that is, within a range of ± 20% with respect to the value obtained by dividing the total supply amount by the number of regions. The supply port for the molecular oxygen-containing gas in each region is on a straight line connecting the central axis and the inner wall of the oxidation reactor, and usually 0.1 to 0.1 mm from the central axis.
It is arranged at a position of 0.9R, preferably 0.2 to 0.8R (R: distance from central axis to inner wall). Particularly preferably, it is installed on the straight line connecting the central axis and the inner wall, in the vicinity of the tip of the stirring blade of the stirrer installed in the oxidation reactor, that is, within ± 0.1 R from the tip. The tip of the stirring blade is usually
Although it is located at a position of 0.2 to 0.7 R from the central axis, if the gas supply port is located at a position of ± 0.1 R from this tip, the reaction will be extremely excellent. The supply position of the gas containing molecular oxygen is ⅔ of the distance from the liquid surface to the bottom of the oxidation reactor.
It is preferably located lower. In the case of a process consisting of main oxidation and additional oxidation, at least main oxidation may be performed according to the present invention.
【０００８】本発明は上述の如く邪魔板で区画された各
領域毎に分子状酸素含有ガスの供給口を有する酸化反応
器を用いる以外は常法に従って行なうことができる。反
応は酢酸溶媒中で行なわれ、この中には２０重量％程度
までの水を含んでいてもよい。触媒は通常、コバルト−
マンガン−臭素の３元素からなっており、その反応液中
の濃度は通常、コバルトが金属換算で１２０〜３０００
ｐｐｍ、好ましくは１５０〜４００ｐｐｍ、マンガンは
コバルトに対して金属換算で０．０１〜３重量倍、臭素
は元素換算で５００〜６０００ｐｐｍ、好ましくは６０
０〜１５００ｐｐｍである。触媒の調整に際しては、コ
バルトとしては酢酸コバルト、ナフテン酸コバルトなど
のコバルト化合物、マンガンとしては酢酸マンガン、ナ
フテン酸マンガンなどのマンガン化合物、臭素としては
臭化水素、臭化ナトリウムなどが用いられる。また、臭
化コバルト、臭化マンガンなどを用いることもできる。The present invention can be carried out according to a conventional method except that the oxidation reactor having the supply port for the molecular oxygen-containing gas is used for each region divided by the baffle plate as described above. The reaction is carried out in an acetic acid solvent, which may contain up to about 20% by weight of water. The catalyst is usually cobalt-
It is composed of three elements, manganese and bromine, and the concentration in the reaction solution is usually 120 to 3000 in terms of metal in terms of cobalt.
ppm, preferably 150 to 400 ppm, manganese is 0.01 to 3 times by weight in terms of metal with respect to cobalt, and bromine is 500 to 6000 ppm in terms of element, preferably 60.
It is 0 to 1500 ppm. When adjusting the catalyst, cobalt compounds such as cobalt acetate and cobalt naphthenate are used as cobalt, manganese compounds such as manganese acetate and manganese naphthenate are used as manganese, and hydrogen bromide and sodium bromide are used as bromine. Further, cobalt bromide, manganese bromide or the like can also be used.
【０００９】酸化反応器内は、１７０〜２３０℃、好ま
しくは１８０〜２１０℃の温度、及び数ｋｇ／ｃｍ2 〜
１００ｋｇ／ｃｍ2 、好ましくは１０〜３０ｋｇ／ｃｍ
2 の圧力に維持される。反応温度が低すぎるとパラキシ
レンを十分に酸化することができない。逆に高すぎても
高純度テレフタル酸が得られないばかりか酢酸の燃焼損
失が増大するので好ましくない。反応時間は通常、３０
〜２００分、好ましくは４０〜１５０分程度である。こ
の間にパラキシレンの９５％以上、好ましくは９８％以
上が酸化される。Inside the oxidation reactor, a temperature of 170 to 230 ° C., preferably 180 to 210 ° C., and several kg / cm 2 to
100 kg / cm 2 , preferably 10-30 kg / cm
Maintained at a pressure of 2 . If the reaction temperature is too low, paraxylene cannot be sufficiently oxidized. On the contrary, if it is too high, not only high-purity terephthalic acid cannot be obtained but also combustion loss of acetic acid increases, which is not preferable. Reaction time is usually 30
~ 200 minutes, preferably about 40-150 minutes. During this period, 95% or more, preferably 98% or more, of para-xylene is oxidized.
【００１０】分子状酸素含有ガスとしては通常は空気な
いしは酸素富化空気が用いられる。ガス中の酸素濃度は
通常１８〜３０容量％、好ましくは２０〜２８容量％で
ある。その供給量は、パラキシレンに対し分子状酸素と
して通常、３〜１００倍モルである。分子状酸素含有ガ
スの供給量の制御は、通常は酸化反応器から系外に流出
する排ガス中の酸素濃度が１．５〜８容量％となるよう
に行なわれる。酸化反応器へのパラキシレンと循環され
てくる反応母液その他の溶媒との供給比率は、反応混合
物中のテレフタル酸濃度（前述の如くパラキシレンの酸
化率は９５％以上に達しているが、それでも存在するパ
ラキシレン及び反応中間体もテレフタル酸に換算して計
算するものとする）が２０〜５０重量％となるように制
御するのが好ましい。Air or oxygen-enriched air is usually used as the molecular oxygen-containing gas. The oxygen concentration in the gas is usually 18 to 30% by volume, preferably 20 to 28% by volume. The supply amount thereof is usually 3 to 100 times mol as molecular oxygen with respect to paraxylene. The supply amount of the molecular oxygen-containing gas is usually controlled so that the oxygen concentration in the exhaust gas flowing out of the system from the oxidation reactor is 1.5 to 8% by volume. The feeding ratio of para-xylene to the circulating reaction mother liquor and other solvents to the oxidation reactor was such that the concentration of terephthalic acid in the reaction mixture (the oxidation rate of para-xylene reached 95% or more as described above, but still It is preferable to control the existing para-xylene and reaction intermediate to be 20 to 50% by weight in terms of terephthalic acid.
【００１１】酸化反応器から抜出された反応混合物は、
所望により更に追酸化してテレフタル酸の純度を向上さ
せたのち、結晶分離工程に送られ、テレフタル酸結晶と
反応母液とに分離される。追酸化は公知であり、酸化反
応器の反応温度よりも低温で行なう低温追酸化と、低温
追酸化したのちこれよりも高い温度で更に追酸化する低
温追酸化−高温追酸化などいくつかの方法が知られてい
る。The reaction mixture withdrawn from the oxidation reactor is
If desired, after further oxidization to improve the purity of terephthalic acid, the terephthalic acid crystals are sent to a crystal separation step and separated into a terephthalic acid crystal and a reaction mother liquor. Additional oxidation is known, and there are several methods such as low temperature additional oxidation that is performed at a temperature lower than the reaction temperature of the oxidation reactor, and low temperature additional oxidation that is performed after low temperature additional oxidation and then higher temperature than this-high temperature additional oxidation. It has been known.
【００１２】テレフタル酸結晶を分離したのちの反応母
液の一部は酸化反応器に循環され、残余は不純物の蓄積
を防止するため系外に排出される。通常は反応母液の１
０〜９０％、好ましくは４０〜８０％が酸化反応器に循
環される。酸化反応器からの排ガスは、酸化反応器上部
に設置されている還流冷却器で冷却し、排ガス中に含ま
れている酢酸や水などの凝縮成分を凝縮させたのち、不
凝縮ガスは系外に排出される。凝縮液は酸化反応器に還
流させるが、凝縮液の一部を系外に排出することによ
り、反応器内の水分を５〜１５重量％と低濃度に調節す
ることもできる。After separating the terephthalic acid crystals, a part of the reaction mother liquor is circulated to the oxidation reactor, and the rest is discharged out of the system to prevent accumulation of impurities. Usually 1 of reaction mother liquor
0 to 90%, preferably 40 to 80% is recycled to the oxidation reactor. Exhaust gas from the oxidation reactor is cooled by a reflux condenser installed above the oxidation reactor to condense condensed components such as acetic acid and water contained in the exhaust gas. Is discharged to. The condensate is refluxed to the oxidation reactor, but the water content in the reactor can be adjusted to a low concentration of 5 to 15% by weight by discharging a part of the condensate out of the system.
【００１３】[0013]
【実施例】以下に実施例及び比較例により本発明を更に
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。なお、反
応装置としては、図１に示す第１酸化反応器１、第２酸
化反応器２、第１晶析器３、第２晶析器４及び遠心分離
機５から成るものを用いた。また、第１酸化反応器とし
ては等間隔に配置された４枚の邪魔板を有する円筒状の
容器（図２，３参照）を用いた。円筒の内径を１．０と
するとき、液深すなわち底部から液面までの高さは２．
２、邪魔板の幅は０．１１であり、分子状酸素含有ガス
の供給口は邪魔板で区画された４個の領域の各々に底部
から０．３の高さの位置に設けられている。また、
「部」は「重量部／時間」である。EXAMPLES The present invention will be described in more detail below with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples unless it exceeds the gist. In addition, as the reaction apparatus, the one comprising the first oxidation reactor 1, the second oxidation reactor 2, the first crystallizer 3, the second crystallizer 4, and the centrifugal separator 5 shown in FIG. 1 was used. As the first oxidation reactor, a cylindrical container having four baffle plates arranged at equal intervals (see FIGS. 2 and 3) was used. When the inner diameter of the cylinder is 1.0, the liquid depth, that is, the height from the bottom to the liquid surface is 2.
2. The width of the baffle is 0.11, and the supply port of the molecular oxygen-containing gas is provided at a position of 0.3 from the bottom in each of the four regions divided by the baffle. . Also,
“Part” is “part by weight / hour”.
【００１４】実施例１ 第１酸化反応器１に、導管６を経てパラキシレン１部、
５％の水を含む酢酸５部、酢酸コバルト（４水和物）
０．００４２部、酢酸マンガン（４水和物）０．００４
５部、臭化水素酸０．００６３４部（４７％水溶液とし
て供給）からなる混合液を供給し、かつ導管７を経て酸
素濃度２１容量％の酸化ガスを供給し、温度１９５℃、
圧力１４．０ｋｇ／ｃｍ2 Ｇ、滞留時間９０分の反応条
件でパラキシレンを酸化した。第１酸化反応器から流出
するガスは反応器上部の冷却凝縮器で冷却して酢酸、水
などの凝縮性成分を凝縮させ、不凝縮ガスは系外に排出
した。第１反応器内の水分を１０％近辺に制御するため
凝縮液のうち１．８部は導管８を経て系外に抜出し、残
余は第１酸化反応器に還流した。また、第１酸化反応器
への酸化ガスの供給は、系外に排出される非凝縮ガス中
の酸素濃度が５．５容量％となるように制御した。生成
したテレフタル酸結晶を含む反応混合物は導管９を経て
第２酸化反応器２に供給した。第２酸化反応器は第１酸
化反応器と同一仕様であるが、４個の酸化ガス供給口の
うち３個は閉鎖し、１個のみ使用した。第２酸化反応器
では１８５℃、１１．０ｋｇ／ｃｍ2 Ｇ、滞留時間４０
分の反応条件で反応を行なった。第２酸化反応器上部の
冷却凝縮器で生成した凝縮液は全量を第２酸化反応器に
還流した。また第２酸化反応器へは導管１０を経て酸化
ガスを供給したが、その量は、系外に排出される非凝縮
ガス中の酸素濃度が５．５容量％となるように制御し
た。第２酸化反応器の反応混合物は導管１１を経て第１
晶析器３へ供給し、第１晶析器３のスラリーは導管１２
を経て第２晶析器４へ供給した。第２晶析器４のスラリ
ーは遠心分離装置５でテレフタル酸結晶と反応母液とに
分離した。分離したテレフタル酸結晶は酢酸で洗浄した
のち乾燥した。結果を第１表に示す。EXAMPLE 1 1 part of para-xylene via conduit 6 into the first oxidation reactor 1,
5 parts acetic acid containing 5% water, cobalt acetate (tetrahydrate)
0.0042 parts, manganese acetate (tetrahydrate) 0.004
A mixed solution of 5 parts and 0.00634 parts of hydrobromic acid (supplied as a 47% aqueous solution) was supplied, and an oxidizing gas having an oxygen concentration of 21% by volume was supplied through a conduit 7 at a temperature of 195 ° C.
Paraxylene was oxidized under the reaction conditions of a pressure of 14.0 kg / cm 2 G and a residence time of 90 minutes. The gas flowing out from the first oxidation reactor was cooled by a cooling condenser in the upper part of the reactor to condense condensable components such as acetic acid and water, and the non-condensed gas was discharged to the outside of the system. In order to control the water content in the first reactor to be around 10%, 1.8 parts of the condensate was withdrawn to the outside of the system via the conduit 8, and the rest was refluxed to the first oxidation reactor. The supply of the oxidizing gas to the first oxidation reactor was controlled so that the oxygen concentration in the non-condensed gas discharged to the outside of the system was 5.5% by volume. The reaction mixture containing the produced terephthalic acid crystals was supplied to the second oxidation reactor 2 via the conduit 9. The second oxidation reactor had the same specifications as the first oxidation reactor, but three of the four oxidizing gas supply ports were closed and only one was used. In the second oxidation reactor, 185 ° C., 11.0 kg / cm 2 G, residence time 40
The reaction was carried out under the reaction conditions of minutes. The whole amount of the condensate produced in the cooling condenser above the second oxidation reactor was refluxed to the second oxidation reactor. Further, the oxidizing gas was supplied to the second oxidation reactor through the conduit 10, and the amount thereof was controlled so that the oxygen concentration in the non-condensed gas discharged to the outside of the system was 5.5% by volume. The reaction mixture of the second oxidation reactor is fed via conduit 11 to the first
The slurry of the first crystallizer 3 is supplied to the crystallizer 3, and the slurry is supplied to the conduit 12
And was supplied to the second crystallizer 4. The slurry of the second crystallizer 4 was separated by a centrifugal separator 5 into terephthalic acid crystals and a reaction mother liquor. The separated terephthalic acid crystals were washed with acetic acid and then dried. The results are shown in Table 1.
【００１５】比較例１ 実施例１において、第１酸化反応器の４個の酸化ガス供
給口のうち３個を閉鎖し、１個の供給口から酸化ガスを
供給した以外は実施例１と全く同様にしてパラキシレン
の酸化を行なった。結果を第１表に示す。Comparative Example 1 The same as Example 1 except that three of four oxidizing gas supply ports of the first oxidation reactor were closed and the oxidizing gas was supplied from one supply port in Comparative Example 1. Paraxylene was similarly oxidized. The results are shown in Table 1.
【００１６】比較例２ 実施例１において、第１酸化反応器の４個の酸化ガス供
給口のうち相対する位置の２個を閉鎖し、残りの２個の
供給口（これも相互に対向する位置にある）から酸化ガ
スを供給した以外は実施例１と全く同様にしてパラキシ
レンの酸化を行なった。結果を第１表に示す。COMPARATIVE EXAMPLE 2 In Example 1, of the four oxidizing gas supply ports of the first oxidation reactor, two at opposite positions were closed, and the remaining two supply ports (which also face each other). Paraxylene was oxidized in exactly the same manner as in Example 1 except that the oxidizing gas was supplied from the (position). The results are shown in Table 1.
【００１７】[0017]
【表１】 注）透過率：テレフタル酸７．５ｇを２Ｎ−水酸化カリ
ウム水溶液５０ｍｌに溶解した溶液につき、光路長１ｃ
ｍの石英セルを用い、分光光度計で３４０ｎｍにおける
透過率を測定[Table 1] Note) Transmittance: Optical path length 1c for a solution of 7.5g terephthalic acid dissolved in 50ml 2N-potassium hydroxide aqueous solution.
Measure the transmittance at 340 nm with a spectrophotometer using a quartz cell of m
【００１８】[0018]
【発明の効果】本発明によれば酸化反応器への分子状酸
素含有ガスの供給を、各邪魔板で区画された領域に分割
して供給することにより、高品質のテレフタル酸を製造
することができる。Industrial Applicability According to the present invention, the supply of the molecular oxygen-containing gas to the oxidation reactor is divided into the regions partitioned by the baffles to supply the terephthalic acid of high quality. You can
【図１】実施例で用いたテレフタル酸製造装置の概念図
である。FIG. 1 is a conceptual diagram of a terephthalic acid production apparatus used in Examples.
【図２】実施例で用いた第１酸化反応器の見取図であ
る。FIG. 2 is a schematic view of a first oxidation reactor used in Examples.
【図３】図２の第１酸化反応器の上方からの見取図であ
る。FIG. 3 is a top view of the first oxidation reactor of FIG.
１ 第１酸化反応器 ２ 第２酸化反応器 ３ 第１晶析器 ４ 第２晶析器 ５ 遠心分離装置 ６ 原料供給導管 ７ 酸化ガス供給導管 ８ 凝縮液抜出し管 １０ 酸化ガス供給導管 ２１ 酸化反応器 ２２ 邪魔板 ２３ 撹拌機 ２４ 酸化ガス供給管 1 First Oxidation Reactor 2 Second Oxidation Reactor 3 First Crystallizer 4 Second Crystallizer 5 Centrifuge 6 Raw Material Supply Pipeline 7 Oxidizing Gas Supply Pipeline 8 Condensate Extraction Pipe 10 Oxidizing Gas Supply Pipeline 21 Oxidation Reaction Vessel 22 Baffle plate 23 Stirrer 24 Oxidizing gas supply pipe
─────────────────────────────────────────────────────
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【手続補正書】[Procedure amendment]
【提出日】平成５年７月５日[Submission date] July 5, 1993
【手続補正１】[Procedure Amendment 1]
【補正対象書類名】明細書[Document name to be amended] Statement
【補正対象項目名】請求項１[Name of item to be corrected] Claim 1
【補正方法】変更[Correction method] Change
【補正内容】[Correction content]
【手続補正２】[Procedure Amendment 2]
【補正対象書類名】明細書[Document name to be amended] Statement
【補正対象項目名】０００２[Name of item to be corrected] 0002
【補正方法】変更[Correction method] Change
【補正内容】[Correction content]
【０００２】[0002]
【従来の技術】テレフタル酸はポリエステルの原料とし
て極めて重要な化合物である。テレフタル酸の製造法と
しては、パラキシレンを重金属及び臭素を含む触媒の存
在下に酢酸溶媒中で分子状酸素含有ガスで酸化する方法
が代表的なものであり、工業的に大規模に実施されてい
る。この方法では、撹拌槽型の酸化反応器に触媒、酢酸
溶媒、パラキシレンおよび分子状酸素含有ガスとを連続
的に供給し、パラキシレンをテレフタル酸に酸化する。
生成したテレフタル酸を含む反応混合物は酸化反応器か
ら抜出され、所望により更に追酸化したのち析出してい
るテレフタル酸結晶を分離回収する。結晶を分離した後
の反応母液は、不純物の蓄積を防ぐためその一部を系外
に排出し、残余は酸化反応器に循環する。燃焼及び系外
への排出等により反応系から失なわれる酢酸溶媒及び触
媒は、新たな酢酸及び触媒を系外から供給することによ
り補充され、系内の酢酸濃度及び触媒濃度等は、常に一
定の状態に保つようにする。2. Description of the Related Art Terephthalic acid is a very important compound as a raw material for polyester. A typical method for producing terephthalic acid is to oxidize para-xylene with a molecular oxygen-containing gas in an acetic acid solvent in the presence of a catalyst containing heavy metals and bromine, which is industrially carried out on a large scale. ing. In this method, a catalyst, an acetic acid solvent, para-xylene and a molecular oxygen-containing gas are continuously supplied to a stirring tank type oxidation reactor to oxidize para-xylene to terephthalic acid.
The produced reaction mixture containing terephthalic acid is discharged from the oxidation reactor, and if necessary, after additional oxidation, the precipitated terephthalic acid crystals are separated and recovered. A part of the reaction mother liquor after separating the crystals is discharged out of the system to prevent accumulation of impurities, and the rest is circulated to the oxidation reactor. Acetic acid solvent and catalyst that are lost from the reaction system due to combustion and discharge to the outside of the system are replenished by supplying new acetic acid and catalyst from outside the system, and the acetic acid concentration and catalyst concentration inside the system are always constant. Try to keep the condition of.
【手続補正３】[Procedure 3]
【補正対象書類名】明細書[Document name to be amended] Statement
【補正対象項目名】０００５[Name of item to be corrected] 0005
【補正方法】変更[Correction method] Change
【補正内容】[Correction content]
【０００５】本発明によれば、内壁面上に複数の邪魔板
が縦方向に並設されている酸化反応器に重金属と臭素を
含む触媒、酢酸溶媒、パラキシレンおよび分子状酸素含
有ガスとを連続的に供給してパラキシレンを酸化するテ
レフタル酸の製造法において、各邪魔板で区画された領
域毎に分子状酸素含有ガスを供給することにより高品質
のテレフタル酸を製造することができる。According to the present invention, a catalyst containing heavy metals and bromine, an acetic acid solvent, para-xylene and a gas containing molecular oxygen are placed in an oxidation reactor in which a plurality of baffles are vertically arranged side by side on an inner wall surface. In the method for producing terephthalic acid in which paraxylene is continuously supplied to oxidize paraxylene, high-quality terephthalic acid can be produced by supplying a molecular oxygen-containing gas to each region divided by each baffle plate.
Claims (3)
溶媒が収容されており、且つ内壁面上に複数の邪魔板が
縦方向に並設されている酸化反応器に、パラキシレンと
分子状酸素含有ガスとを連続的に供給してパラキシレン
を酸化するテレフタル酸の製造方法において、各邪魔板
で区画された領域毎に分子状酸素含有ガスを供給するこ
とを特徴とする方法。1. Paraxylene and a molecular form are placed in an oxidation reactor containing an acetic acid solvent in which a catalyst containing heavy metal and bromine is dissolved, and a plurality of baffles arranged vertically on an inner wall surface. A method for producing terephthalic acid in which an oxygen-containing gas is continuously supplied to oxidize para-xylene, wherein a molecular oxygen-containing gas is supplied to each region partitioned by each baffle plate.
上で、中心軸から０．２〜０．８Ｒ（Ｒ：中心軸から内
壁までの距離）の位置に分子状酸素含有ガスを供給する
ことを特徴とする請求項１記載の方法。2. A molecular oxygen-containing gas is placed at a position of 0.2 to 0.8 R (R: distance from the central axis to the inner wall) on the straight line connecting the central axis and the inner wall of the oxidation reactor. A method according to claim 1, characterized in that it is provided.
酸化反応器の中心軸と内壁とを結ぶ直線上で、撹拌翼の
先端から±０．１Ｒ（Ｒ：中心軸から内壁までの距離）
の位置に分子状酸素含有ガスを供給することを特徴とす
る請求項１又は２記載の方法。3. The oxidation reactor is provided with a stirring blade, and on the straight line connecting the central axis of the oxidation reactor and the inner wall, ± 0.1 R from the tip of the stirring blade (R: from the central axis to the inner wall) distance)
3. The method according to claim 1, wherein the molecular oxygen-containing gas is supplied to the position.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP11157393A JP3232774B2 (en) | 1993-05-13 | 1993-05-13 | Method for producing high-purity terephthalic acid |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP11157393A JP3232774B2 (en) | 1993-05-13 | 1993-05-13 | Method for producing high-purity terephthalic acid |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH06321855A true JPH06321855A (en) | 1994-11-22 |
| JP3232774B2 JP3232774B2 (en) | 2001-11-26 |
Family
ID=14564806
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP11157393A Expired - Lifetime JP3232774B2 (en) | 1993-05-13 | 1993-05-13 | Method for producing high-purity terephthalic acid |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3232774B2 (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5696285A (en) * | 1995-12-29 | 1997-12-09 | Praxair Technology, Inc. | Production of terephthalic acid with excellent optical properties through the use of pure or nearly pure oxygen as the oxidant in p-xylene oxidation |
| JP2008500946A (en) * | 2003-06-13 | 2008-01-17 | テレフタラトス メキシカノス エス．エー． デ シー．ヴイ． | Method and apparatus for efficient oxidation of alkylaromatic compounds |
| KR100988684B1 (en) * | 2008-04-16 | 2010-10-18 | 삼남석유화학 주식회사 | Oxidation reactor for manufacturing of crude terephtalic acid |
-
1993
- 1993-05-13 JP JP11157393A patent/JP3232774B2/en not_active Expired - Lifetime
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5696285A (en) * | 1995-12-29 | 1997-12-09 | Praxair Technology, Inc. | Production of terephthalic acid with excellent optical properties through the use of pure or nearly pure oxygen as the oxidant in p-xylene oxidation |
| JP2008500946A (en) * | 2003-06-13 | 2008-01-17 | テレフタラトス メキシカノス エス．エー． デ シー．ヴイ． | Method and apparatus for efficient oxidation of alkylaromatic compounds |
| JP4780566B2 (en) * | 2003-06-13 | 2011-09-28 | テレフタラトス メキシカノス エス．エー． デ シー．ヴイ． | Method and apparatus for efficient oxidation of alkylaromatic compounds |
| KR100988684B1 (en) * | 2008-04-16 | 2010-10-18 | 삼남석유화학 주식회사 | Oxidation reactor for manufacturing of crude terephtalic acid |
Also Published As
| Publication number | Publication date |
|---|---|
| JP3232774B2 (en) | 2001-11-26 |
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