JPH09124549A - Production of alkylbenzoic acid - Google Patents
Production of alkylbenzoic acidInfo
- Publication number
- JPH09124549A JPH09124549A JP7285116A JP28511695A JPH09124549A JP H09124549 A JPH09124549 A JP H09124549A JP 7285116 A JP7285116 A JP 7285116A JP 28511695 A JP28511695 A JP 28511695A JP H09124549 A JPH09124549 A JP H09124549A
- Authority
- JP
- Japan
- Prior art keywords
- reaction
- heat
- water
- acid
- oxidation
- 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.)
- Pending
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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
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
- Low-Molecular Organic Synthesis Reactions Using Catalysts (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明はアルキルベンゼン類
を液相酸化してアルキル安息香酸を製造する方法に関
し、詳しくは該液相酸化の方法および反応熱を除去する
方法に関する。TECHNICAL FIELD The present invention relates to a method for producing an alkylbenzoic acid by liquid-phase oxidation of alkylbenzenes, and more particularly to a method for the liquid-phase oxidation and a method for removing reaction heat.
【０００２】[0002]
【従来の技術】キシレン、メシチレンなどに代表される
アルキルベンゼン類を分子状酸素含有ガスにより液相に
て可溶性の重金属触媒を用いて酸化することにより、一
個のアルキル基をカルボン酸に転化して安息香酸類を製
造することは、たとえば米国特許第２７１２５４９号、
米国特許第２７１２５５１号、特公昭５２−４６２１７
号および特公昭５６−８８１６号などから公知である。BACKGROUND ART Oxidation of alkylbenzenes represented by xylene and mesitylene with a molecular oxygen-containing gas in a liquid phase using a heavy metal catalyst soluble in the liquid phase converts one alkyl group into a carboxylic acid to give benzoic acid. Producing acids is described, for example, in US Pat. No. 2,712,549,
U.S. Pat. No. 2,712,551, Japanese Patent Publication No. 52-46217
And Japanese Patent Publication No. 56-8816.
【０００３】上記の米国特許においてキシレンを酸化し
てトルイル酸を製造するとき、同時にトルイル酸が更に
酸化された反応液に不溶性のフタル酸が副生するため、
酸化反応熱を除去する熱交換器の伝熱面にフタル酸が沈
着析出し除熱が不可能になること、更には結晶分離でト
ルイル酸を回収する場合にフタル酸が混入するなどの問
題が生じることが記載されている。前者の問題に関して
は加圧での反応液を常圧タンクにフラシュして除熱する
方法が採られているが、しかし工業的にはフラシュタン
クを設け反応液を循環する必要があり、かつプロセスも
複雑になり、トラブルも予測される。後者の問題に関し
ては反応液を熱時で濾過することによりフタル酸を除去
している。しかし、この方法では反応液中に溶解するフ
タル酸を除くことはできず、さらに冷却してトルイル酸
を得る場合には相当量のフタル酸が製品に混入を避ける
ことが出来ない。In the above-mentioned US patent, when xylene is oxidized to produce toluic acid, at the same time, insoluble phthalic acid is by-produced in the reaction solution obtained by further oxidizing toluic acid.
There is a problem that phthalic acid is deposited and deposited on the heat transfer surface of the heat exchanger that removes the heat of oxidation reaction, making it impossible to remove heat, and that phthalic acid is mixed when recovering toluic acid by crystal separation. It is stated that it occurs. Regarding the former problem, a method of flushing the reaction solution under pressure to a normal pressure tank to remove heat is adopted, but industrially it is necessary to install a flush tank and circulate the reaction solution, and process Becomes complicated and troubles are predicted. Regarding the latter problem, phthalic acid is removed by filtering the reaction solution while it is hot. However, this method cannot remove the phthalic acid dissolved in the reaction solution, and when further cooling to obtain toluic acid, a considerable amount of phthalic acid cannot be avoided from being mixed in the product.
【０００４】[0004]
【発明が解決しようとする課題】本発明の目的は、アル
キルベンゼン類を液相酸化してモノカルボン酸であるア
ルキル安息香酸を製造する際に副生するジカルボン酸に
よる装置運転上のトラブルや品質低下の問題の解決する
方法を提供することにある。DISCLOSURE OF THE INVENTION An object of the present invention is to cause troubles in equipment operation and deterioration of quality due to dicarboxylic acid by-produced in the production of alkylbenzoic acid which is a monocarboxylic acid by liquid-phase oxidation of alkylbenzenes. To provide a solution to the problem.
【０００５】[0005]
【課題を解決するための手段】発明者は上記の如き課題
を解決するために鋭意検討した結果、酸化反応における
ジカルボン酸の生成それ自身を極力抑えることが重要で
あり、酸化反応の条件とジカルボン酸の生成の関係か
ら、反応圧力を低くし反応液の沸騰温度で蒸発除熱を行
いながら原料アルキルベンゼンの転化率を低く抑えるこ
とにより、ジカルボン酸の生成割合が下がり、かつ冷却
伝熱に頼らないために温度調節もスムーズとなること、
またジカルボン酸の生成が抑えられるため、蒸留精製で
もトラブル無く、高純度のアルキル安息香酸を高い取得
率で得られることを見出し、本発明に到達した。Means for Solving the Problems As a result of intensive studies for solving the above problems, the inventor has found that it is important to suppress dicarboxylic acid formation itself in the oxidation reaction as much as possible. Due to the formation of acid, the reaction pressure is lowered and the conversion rate of the raw material alkylbenzene is kept low while evaporative heat removal is performed at the boiling temperature of the reaction solution, which reduces the production rate of dicarboxylic acid and does not rely on cooling heat transfer. For that reason, the temperature can be adjusted smoothly.
Further, they have found that a high-purity alkylbenzoic acid can be obtained at a high acquisition rate without any trouble even by distillation purification because the production of dicarboxylic acid is suppressed, and the present invention has been completed.
【０００６】即ち本発明は、炭素数が１から３までのア
ルキル基を少なくとも２個有するアルキルベンゼン類
を、液相にて可溶性の重金属触媒を用いて分子状酸素含
有ガスで酸化する反応により、一個のアルキル基をカル
ボン酸に転化してアルキル安息香酸を製造する方法にお
いて、アルキルベンゼンの反応率を２５％以下とするこ
とを特徴とするアルキル安息香酸の製造法および、該酸
化反応を沸騰除熱状態で操作し、蒸発熱により反応熱の
除去を行う方法である。That is, according to the present invention, one alkylbenzene having at least two alkyl groups having 1 to 3 carbon atoms is oxidized in a liquid phase with a molecular oxygen-containing gas using a soluble heavy metal catalyst to obtain one alkylbenzene. In the method for producing an alkylbenzoic acid by converting an alkyl group of carboxylic acid to a carboxylic acid, the reaction rate of alkylbenzene is 25% or less, and the oxidation reaction is carried out under boiling heat removal condition. Is a method of removing the heat of reaction by the heat of evaporation.
【０００７】[0007]
【発明の実施の形態】原料に用いられるアルキルベンゼ
ンとしてはベンゼン核に２〜６個の置換基を有するもの
であって、少なくとも２個の置換基は炭素数１〜３のア
ルキル基を有するものである。本発明においては特にオ
ルソキシレン、メタキシレン、パラキシレン、メシチレ
ン、プソイドキュメンなどメチルベンゼン類が好適に用
いられ、それぞれ対応するオルソトルイル酸、メタトル
イル酸、パラトルイル酸、3、5-ジメチル安息香酸、3、4-
ジメチル安息香酸などが製造される。BEST MODE FOR CARRYING OUT THE INVENTION The alkylbenzene used as a raw material has 2 to 6 substituents in the benzene nucleus, and at least 2 substituents have an alkyl group having 1 to 3 carbon atoms. is there. In the present invention, ortho-xylene, meta-xylene, para-xylene, mesitylene, pseudocumene is preferably used methylbenzenes, respectively corresponding ortho-toluic acid, meta-toluic acid, para-toluic acid, 3,5-dimethylbenzoic acid, 3, 4 -
Dimethylbenzoic acid and the like are produced.
【０００８】アルキルベンゼンの酸化反応は公知の方法
が適用される。反応溶媒としてはベンゼンなどの酸化さ
れにくい溶媒を用いても良いが、原料のアルキルベンゼ
ンそれ自身を溶媒にすることが好ましい。溶媒に可溶性
の重金属触媒としてコバルト、マンガン、セリウムなど
の有機酸塩が有効であり、ナフテン酸コバルト、ナフテ
ン酸マンガン、トルイル酸コバルトなどが好適である。
触媒の反応液中の金属濃度は１０〜３０００ｐｐｍ、好
ましくは３０〜３００ｐｐｍである。A known method is applied to the oxidation reaction of alkylbenzene. As the reaction solvent, a solvent that is not easily oxidized, such as benzene, may be used, but it is preferable to use the raw material alkylbenzene itself as the solvent. Organic acid salts of cobalt, manganese, cerium, etc. are effective as the solvent-soluble heavy metal catalyst, and cobalt naphthenate, manganese naphthenate, cobalt toluate, etc. are preferable.
The metal concentration in the reaction liquid of the catalyst is 10 to 3000 ppm, preferably 30 to 300 ppm.
【０００９】酸化反応温度はアルキルベンゼンの種類に
もよるが一般的に１００〜２００℃好ましくは１２０〜
１８０℃である。このとき反応器内の反応液は沸騰除熱
状態になるよう反応圧力が調節される。分子状酸素含有
ガスとしては通常空気が用いられ、反応系に酸素が十分
に分散するように吹き込まれる。また爆発限界を避ける
ために定常状態での出口の排ガス中の酸素濃度が６％以
下になるよう吹き込む空気量が調節される。The oxidation reaction temperature depends on the kind of alkylbenzene, but is generally 100 to 200 ° C., preferably 120 to 200 ° C.
It is 180 ° C. At this time, the reaction pressure is adjusted so that the reaction liquid in the reactor is in a boiling heat removal state. Air is usually used as the molecular oxygen-containing gas, and is blown so that oxygen is sufficiently dispersed in the reaction system. In order to avoid the explosion limit, the amount of air blown is adjusted so that the oxygen concentration in the exhaust gas at the outlet in the steady state is 6% or less.
【００１０】本発明において反応液の沸騰除熱状態とは
反応液の厳密な沸点ではなく、吹き込まれる空気による
反応熱が排ガスと同伴する蒸気による蒸発熱と釣り合っ
ている温度、圧力の状態である。実際には沸点の高いア
ルキルベンゼンの大過剰の反応液を沸騰除熱状態にする
には反応圧力が常圧付近になり、反応速度が低下する場
合が多い。そこで反応器内に水を連続的に注入しアルキ
ルベンゼンと水の共沸状態にすることにより沸点を下げ
る方法が好適に行われる。注入された水は酸化で本来生
じた水と共に蒸発し還流冷却器で凝縮し、油相のみ反応
器に還流され、水相は反応系外に抜液されるので、反応
液中に水は蓄積されない。また水を注入する代わりに、
酸化で生じた水を凝縮液から全量抜き出さずに、一部還
流させても良い。反応器内への水の注入量あるいは還流
量は反応装置全体の放熱量、酸化反応速度で異なってく
るので反応温度が所定温度で安定するように圧力で調節
される。好ましい圧力範囲は１〜１０ Kg/cm2 G であ
る。In the present invention, the boiling heat removal state of the reaction solution is not a strict boiling point of the reaction solution but a temperature and pressure state in which the reaction heat of the blown air is balanced with the heat of vaporization of the vapor accompanying the exhaust gas. . In actuality, in order to bring a large excess of reaction liquid of alkylbenzene having a high boiling point to the boiling heat removal state, the reaction pressure becomes close to normal pressure, and the reaction rate often decreases. Therefore, a method of lowering the boiling point by continuously injecting water into the reactor to make it into an azeotropic state of alkylbenzene and water is suitably performed. The injected water evaporates with the water originally generated by oxidation and condenses in the reflux condenser, and only the oil phase is returned to the reactor, and the water phase is drained to the outside of the reaction system, so water accumulates in the reaction solution. Not done. Instead of injecting water again,
The water generated by the oxidation may be partially refluxed without extracting the entire amount from the condensate. The amount of water injected or the amount of reflux into the reactor varies depending on the amount of heat radiated from the reaction apparatus and the rate of oxidation reaction, so the pressure is adjusted so that the reaction temperature is stable at a predetermined temperature. The preferred pressure range is 1 to 10 Kg / cm 2 G.
【００１１】反応の形式は通常、撹拌装置の付いた槽型
の反応器を用いて、バッチ式、セミバッチ式、および連
続式に反応することができるが、工業的には連続式で反
応を行うことが好ましい。反応生成物は蒸留によって未
反応のアルキルベンゼンと生成アルキル安息香酸を回収
するか、一旦、冷却し結晶化によって生成アルキル安息
香酸を分離後、蒸留して未反応アルキルベンゼンを回収
する。本発明の方法によれば、反応生成物はジカルボン
酸含量が少ないため、塔底液の流動性が良いので釜残抜
き出しのトラブルがなく、アルキル安息香酸の取得率が
高く、且つ製品アルキル安息香酸中にはジカルボン酸が
含まれないので、蒸留精製が特に望ましい態様である。The reaction is usually carried out in a batch type, a semi-batch type and a continuous type using a tank type reactor equipped with a stirrer, but industrially the reaction is carried out in a continuous type. It is preferable. For the reaction product, unreacted alkylbenzene and the generated alkylbenzoic acid are recovered by distillation, or the reaction product is once cooled to separate the generated alkylbenzoic acid by crystallization and then distilled to recover the unreacted alkylbenzene. According to the method of the present invention, since the reaction product has a low dicarboxylic acid content, the fluidity of the bottom liquid is good, so there is no trouble withdrawing from the bottom of the kettle, the acquisition rate of alkylbenzoic acid is high, and the product alkylbenzoic acid Since no dicarboxylic acid is contained therein, distillation purification is a particularly desirable mode.
【００１２】次に実施例をもって本発明を更に具体的に
説明する。但し本発明はこれらに限定されるものではな
い。Next, the present invention will be described more specifically with reference to Examples. However, the present invention is not limited to these.
【００１３】実施例１ ＳＵＳ３１６製の還流冷却器、撹拌機および空気吹き込
み管を有する１０００ｍｌのオートクレーブに原料メタ
キシレンを２００ｇ、触媒ナフテン酸コバルト(Co:6wt
%) ０．５ｇを仕込み窒素ガスで 5 Kg/cm2 G に加圧し
た後、１５０℃に昇温する。反応圧力を 5 Kg/cm2 G に
を維持しながら、出口酸素濃度が６％を越えないよう約
７０Ｌ／Ｈｒ（常圧換算）の空気を吹き込んだ。このと
き十分のガス接触が出来るよう撹拌羽根による撹拌回転
速度は８００ｒｐｍに制御した。反応温度を１５５〜１
６０℃に保つように定量ポンプで約３０ｇ／ｈの速度で
水を空気の吹き込みラインを経由して反応器に注入して
１時間反応を行った。この間、反応圧力を上げると反応
温度が直ぐ上昇し、圧力を下げると反応温度も追従して
低下することから、この反応条件では沸騰状態であるこ
とが確認された。還流冷却器の下部ポットから注入した
水と酸化反応で生成した水の合計量３６ｇを連続的に抜
き出した。反応後、生成物を取り出し分析を行なった結
果、原料のメタキシレンの転化率は１８．５％であっ
た。目的生成物のメタトルイル酸選択率は７２．５ｍｏ
ｌ％、ジカルボン酸のイソフタル酸への選択率は１．９
ｍｏｌ％であった。この反応液をそのまま蒸留装置で減
圧下２００ｍｍＨｇでメタキシレンおよび軽沸分を留去
後、真空度１５ｍｍＨｇで１５０〜１６０℃においてメ
タトルイル酸留分３２ｇを取得した。（取得率９３％）
この留分にはイソフタル酸は検出されずメタトルイル酸
純度は９８．２ｗｔ％であった。Example 1 In a 1000 ml autoclave having a SUS316 reflux condenser, a stirrer and an air blowing tube, 200 g of raw material metaxylene and a catalyst cobalt naphthenate (Co: 6 wt)
%) 0.5 g was charged, the pressure was increased to 5 Kg / cm 2 G with nitrogen gas, and the temperature was raised to 150 ° C. While maintaining the reaction pressure at 5 Kg / cm 2 G, about 70 L / Hr (normal pressure conversion) of air was blown in so that the outlet oxygen concentration did not exceed 6%. At this time, the stirring rotation speed by the stirring blade was controlled to 800 rpm so that sufficient gas contact could be achieved. The reaction temperature is 155-1
Water was injected into the reactor through an air blowing line at a rate of about 30 g / h by a metering pump so as to maintain the temperature at 60 ° C, and the reaction was carried out for 1 hour. During this period, when the reaction pressure was increased, the reaction temperature immediately increased, and when the pressure was decreased, the reaction temperature also followed and decreased. Therefore, it was confirmed that the reaction conditions were boiling. A total amount of 36 g of water injected from the lower pot of the reflux condenser and water produced by the oxidation reaction was continuously withdrawn. After the reaction, the product was taken out and analyzed, and as a result, the conversion rate of metaxylene as a raw material was 18.5%. Metatoluic acid selectivity of target product is 72.5mo
1%, the selectivity of dicarboxylic acid to isophthalic acid is 1.9
It was mol%. The reaction solution was directly distilled off in a distillation apparatus under reduced pressure at 200 mmHg to remove meta-xylene and light-boiling components, and then 32 g of metatoluic acid fraction was obtained at 150 to 160 ° C. under a vacuum degree of 15 mmHg. (Acquisition rate 93%)
Isophthalic acid was not detected in this fraction, and the purity of metatoluic acid was 98.2 wt%.
【００１４】比較例１ ＳＵＳ３１６製の還流冷却器、撹拌機および空気吹き込
み管を有する１０００ｍｌのオートクレーブに原料メタ
キシレンを２００ｇ、触媒ナフテン酸コバルト(Co:6wt
%) ０．５ｇを仕込み窒素ガスで 5 Kg/cm2 G に加圧し
た後、１５０℃に昇温した。反応圧力を10 Kg/cm2 G に
維持しながら、出口酸素濃度が６％を越えないよう約７
０Ｌ／Ｈｒ（常圧換算）の空気を吹き込んだ。このとき
十分のガス接触が出来るよう撹拌羽根による撹拌回転速
度は８００ｒｐｍに制御した。反応温度を１５５〜１６
０℃に保つようにオートクレーブのジャケットの熱媒温
度を調節して２時間反応を行った。還流冷却器の下部ポ
ットから酸化反応で生成した水の合計量１２ｇを連続的
に抜き出した。反応後、生成物を取り出し分析を行なっ
た結果、原料のメタキシレンの転化率は２７．９％であ
った。目的生成物のメタトルイル酸選択率は７４．２ｍ
ｏｌ％、ジカルボン酸のイソフタル酸への選択率は４．
４ｍｏｌ％であった。オートクレーブ内壁の冷却面には
イソフタル酸が付着して白くなっていた。この反応液を
そのまま蒸留装置で減圧下２００ｍｍＨｇでメタキシレ
ンおよび軽沸分を留去後、真空度１５ｍｍＨｇで１５０
〜１６０℃においてメタトルイル酸留分４５ｇを取得し
た（取得率８５％）。この蒸留の最後においては残留イ
ソフタル酸により蒸留釜内の液の粘度が上昇し、かなり
の量のメタトルイル酸をボトムに付着したため取得率が
低下した。また釜残の流動性が悪くなったため、抜き出
すために溶剤を加えて再加熱して流動化する必要があっ
た。Comparative Example 1 200 g of raw material meta-xylene and a catalyst cobalt naphthenate (Co: 6 wt) were placed in a 1000 ml autoclave having a SUS316 reflux condenser, an agitator and an air blowing tube.
%) 0.5 g was charged, the pressure was increased to 5 Kg / cm 2 G with nitrogen gas, and the temperature was raised to 150 ° C. Keeping the reaction pressure at 10 Kg / cm 2 G, keep the outlet oxygen concentration at about 7% so as not to exceed 6%.
Air of 0 L / Hr (converted to normal pressure) was blown. At this time, the stirring rotation speed by the stirring blade was controlled to 800 rpm so that sufficient gas contact could be achieved. The reaction temperature is 155-16
The temperature of the heat medium in the jacket of the autoclave was adjusted so as to keep it at 0 ° C, and the reaction was carried out for 2 hours. A total amount of 12 g of water produced by the oxidation reaction was continuously withdrawn from the lower pot of the reflux condenser. After the reaction, the product was taken out and analyzed, and as a result, the conversion rate of metaxylene as a raw material was 27.9%. The target product has a metatoluic acid selectivity of 74.2 m.
ol%, the selectivity of dicarboxylic acid to isophthalic acid is 4.
It was 4 mol%. Isophthalic acid had adhered to the cooling surface of the inner wall of the autoclave and was white. The reaction liquid was distilled as it was in a distillation apparatus under reduced pressure at 200 mmHg to remove meta-xylene and light-boiling components, and then at a vacuum degree of 15 mmHg for 150 minutes.
45 g of a metatoluic acid fraction was obtained at ˜160 ° C. (acquisition rate 85%). At the end of this distillation, the residual isophthalic acid increased the viscosity of the liquid in the distillation pot, and a considerable amount of metatoluic acid was attached to the bottom, thus lowering the acquisition rate. Further, since the fluidity of the residue in the kettle became poor, it was necessary to add a solvent and reheat it to fluidize it in order to extract it.
【００１５】[0015]
【発明の効果】本発明の方法により原料アルキルベンゼ
ンの転化率を低く抑えることにより、ジカルボン酸の生
成が抑えられるため、蒸留精製でもトラブル無く、高純
度のアルキル安息香酸を高い取得率で得られる。また転
化率を低く抑えるために、本発明により反応圧力を低く
し反応液の沸騰温度で蒸発除熱を行いながら酸化反応を
行うようにすることにより、冷却伝熱に頼らないために
温度調節もスムーズとなり、ジカルボン酸の生成割合を
更に低下させることができるので、工業的に極めて有利
にアルキル安息香酸を製造することができる。EFFECT OF THE INVENTION By controlling the conversion rate of the raw material alkylbenzene to a low level by the method of the present invention, the production of dicarboxylic acid can be suppressed, so that high-purity alkylbenzoic acid can be obtained at a high acquisition rate without trouble even by distillation purification. Further, in order to suppress the conversion rate to a low level, the reaction pressure is reduced according to the present invention so that the oxidation reaction is carried out while evaporative heat removal is carried out at the boiling temperature of the reaction solution. Since it becomes smooth and the production ratio of dicarboxylic acid can be further reduced, it is possible to produce an alkylbenzoic acid extremely industrially extremely advantageously.
【手続補正書】[Procedure amendment]
【提出日】平成８年１０月２３日[Submission date] October 23, 1996
【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[Correction target item name] Claim 1
【補正方法】変更[Correction method] Change
【補正内容】[Correction contents]
【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 contents]
【０００２】[0002]
【従来の技術】キシレン、メシチレンなどに代表される
アルキルベンゼン類を分子状酸素含有ガスにより液相に
て可溶性の重金属触媒を用いて酸化することにより、一
個のアルキル基をカルボキシル基に転化して安息香酸類
を製造することは、たとえば米国特許第２７１２５４９
号、米国特許第２７１２５５１号、特公昭５２−４６２
１７号および特公昭５６−８８１６号などから公知であ
る。BACKGROUND ART Oxidation of alkylbenzenes represented by xylene and mesitylene with a molecular oxygen-containing gas in the liquid phase using a heavy metal catalyst soluble in the liquid phase converts one alkyl group into a carboxyl group to give benzoic acid. Producing acids is described, for example, in US Pat. No. 2,712,549.
No. 2,712,551, Japanese Patent Publication No. 52-462.
No. 17 and Japanese Patent Publication No. 56-8816 are known.
【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】０００３[Correction target item name] 0003
【補正方法】変更[Correction method] Change
【補正内容】[Correction contents]
【０００３】上記の米国特許においてキシレンを酸化し
てトルイル酸を製造するとき、同時にトルイル酸が更に
酸化された反応液に不溶性のフタル酸が副生するため、
酸化反応熱を除去する熱交換器の伝熱面にフタル酸が沈
着析出し除熱が不可能になること、更には結晶分離でト
ルイル酸を回収する場合にフタル酸が混入するなどの問
題を生じることが記載されている。前者の除熱の問題に
関しては加圧での反応液を常圧タンクフラシュして除熱
する方法が採られているが、しかし工業的にはフラシュ
タンクを設ける必要があり、かつプロセスも複雑にな
り、トラブルも予測される。後者のフタル酸の混入の問
題に関しては反応液を熱時で濾過することによりフタル
酸を除去している。しかし、この方法では反応液中に溶
解している分のフタル酸を除くことはできず、さらに冷
却してトルイル酸を結晶として得る場合には相当量のフ
タル酸が製品に混入することを避けることが出来ない。In the above-mentioned US patent, when xylene is oxidized to produce toluic acid, at the same time, insoluble phthalic acid is by-produced in the reaction solution obtained by further oxidizing toluic acid.
The phthalic acid to the heat transfer surface of the heat exchanger to remove the heat of oxidation reaction is impossible deposits precipitated heat removal, the problems such as more phthalic acid is mixed when recovering toluic acid crystals separated It is stated that it occurs. Regarding the former problem of heat removal, a method is used in which the reaction solution under pressure is flushed by flushing with a normal pressure tank, but industrially it is necessary to provide a flush tank and the process is complicated. And troubles are predicted. Regarding the latter problem of phthalic acid contamination, phthalic acid is removed by filtering the reaction solution while it is hot. However, this method cannot remove the amount of phthalic acid dissolved in the reaction solution, and avoids the incorporation of a considerable amount of phthalic acid into the product when cooling and obtaining toluic acid as crystals. I can't.
【手続補正４】[Procedure amendment 4]
【補正対象書類名】明細書[Document name to be amended] Statement
【補正対象項目名】０００５[Correction target item name] 0005
【補正方法】変更[Correction method] Change
【補正内容】[Correction contents]
【０００５】[0005]
【課題を解決するための手段】発明者は上記の如き課題
を解決するために鋭意検討した結果、酸化反応における
ジカルボン酸の生成それ自身を極力抑えることが重要で
あり、酸化反応の条件とジカルボン酸の生成の関係か
ら、反応圧力を低くし反応液の沸騰状態で蒸発除熱を行
いながら原料アルキルベンゼンの転化率を低く抑えるこ
とにより、ジカルボン酸の生成割合が下がり、かつ冷却
伝熱に頼らないために温度調節もスムーズとなること、
またジカルボン酸の生成が抑えられるため、蒸留精製で
もトラブル無く、高純度のアルキル安息香酸を高い取得
率で得られることを見出し、本発明に到達した。Means for Solving the Problems As a result of intensive studies for solving the above problems, the inventor has found that it is important to suppress dicarboxylic acid formation itself in the oxidation reaction as much as possible. Due to the relationship of acid formation, the reaction pressure is lowered and the conversion rate of the raw material alkylbenzene is kept low while performing heat removal by evaporation in the boiling state of the reaction solution, which reduces the production rate of dicarboxylic acid and does not rely on cooling heat transfer. For that reason, the temperature can be adjusted smoothly.
Further, they have found that a high-purity alkylbenzoic acid can be obtained at a high acquisition rate without any trouble even by distillation purification because the production of dicarboxylic acid is suppressed, and the present invention has been completed.
【手続補正５】[Procedure Amendment 5]
【補正対象書類名】明細書[Document name to be amended] Statement
【補正対象項目名】０００６[Correction target item name] 0006
【補正方法】変更[Correction method] Change
【補正内容】[Correction contents]
【０００６】即ち本発明は、炭素数が１から３までのア
ルキル基を少なくとも２個有するアルキルベンゼン類
を、液相にて可溶性の重金属触媒を用いて分子状酸素含
有ガスで酸化する反応により、一個のアルキル基をカル
ボキシル基に転化してアルキル安息香酸を製造する方法
において、アルキルベンゼンの反応率を２５％以下とす
ることを特徴とするアルキル安息香酸の製造法および、
該酸化反応を沸騰除熱状態で操作し、蒸発熱により反応
熱の除去を行う方法である。That is, according to the present invention, one alkylbenzene having at least two alkyl groups having 1 to 3 carbon atoms is oxidized in a liquid phase with a molecular oxygen-containing gas using a soluble heavy metal catalyst to obtain one alkylbenzene. Cal the alkyl group
A method for producing an alkylbenzoic acid by converting it to a voxyl group , wherein the reaction rate of alkylbenzene is 25% or less, and the method for producing an alkylbenzoic acid,
This is a method of operating the oxidation reaction in a boiling heat removal state and removing the heat of reaction by the heat of evaporation.
【手続補正６】[Procedure correction 6]
【補正対象書類名】明細書[Document name to be amended] Statement
【補正対象項目名】００１０[Correction target item name] 0010
【補正方法】変更[Correction method] Change
【補正内容】[Correction contents]
【００１０】本発明において反応液の沸騰除熱状態とは
反応液の厳密な沸点ではなく、吹き込まれる空気による
反応熱が排ガスと同伴する蒸気による蒸発熱と釣り合っ
ている温度、圧力の状態である。実際には沸点の高いア
ルキルベンゼンの大過剰の反応液を沸騰除熱状態にする
には反応圧力が常圧付近になり、反応速度が低下する場
合が多い。そこで反応器内に水を連続的に注入しアルキ
ルベンゼンと水の共沸状態にすることにより沸点が下が
り加圧状態での反応が十分な反応速度で得られるように
なる。注入された水は酸化で本来生じた水と共に蒸発し
還流冷却器で凝縮し、油相のみ反応器に還流され、水相
は反応系外に抜液されるので、反応液中に水は蓄積され
ない。また水を注入する代わりに、酸化で生じた水を凝
縮液から全量抜き出さずに、一部還流させても良い。反
応器内への水の注入量あるいは還流量は反応装置全体の
放熱量、酸化反応速度で異なってくるので所定温度・圧
力で安定するように調節される。好ましい圧力範囲は１
〜１０ Kg/cm2 G である。In the present invention, the boiling heat removal state of the reaction solution is not a strict boiling point of the reaction solution but a temperature and pressure state in which the reaction heat of the blown air is balanced with the heat of vaporization of the vapor accompanying the exhaust gas. . In actuality, in order to bring a large excess of reaction liquid of alkylbenzene having a high boiling point to the boiling heat removal state, the reaction pressure becomes close to normal pressure, and the reaction rate often decreases. Therefore, the boiling point is lowered by continuously injecting water into the reactor and making it into an azeotropic state with alkylbenzene and water.
So that the reaction under high pressure can be obtained at a sufficient reaction rate
Become . The injected water evaporates with the water originally generated by oxidation and condenses in the reflux condenser, and only the oil phase is returned to the reactor, and the water phase is drained to the outside of the reaction system, so water accumulates in the reaction solution. Not done. Further, instead of injecting water, a part of the water generated by oxidation may be refluxed without being extracted from the condensate. Injection of water into the reactor or the reflux amount is the amount of heat dissipation across the reactor, a predetermined temperature and pressure so it varies in the oxidation reaction rate
Adjusted to be force stable . The preferred pressure range is 1
It is about 10 Kg / cm 2 G.
Claims (4)
くとも２個有するアルキルベンゼン類を、液相にて可溶
性の重金属触媒を用いて分子状酸素含有ガスで酸化する
反応により、一個のアルキル基をカルボン酸に転化して
アルキル安息香酸を製造する方法において、アルキルベ
ンゼンの反応率を２５％以下とすることを特徴とするア
ルキル安息香酸の製造法1. An alkyl group having at least two alkyl groups having 1 to 3 carbon atoms is oxidized with a molecular oxygen-containing gas in a liquid phase using a soluble heavy metal catalyst to give one alkyl group. A method for producing an alkylbenzoic acid by converting a carboxylic acid to a carboxylic acid, wherein the reaction rate of alkylbenzene is 25% or less.
により反応熱の除去を行う請求項１記載のアルキル安息
香酸の製造法2. The method for producing an alkylbenzoic acid according to claim 1, wherein the oxidation reaction is operated in a boiling heat removal state, and the heat of evaporation is used to remove the heat of reaction.
ルキルベンゼンとの共沸によって除熱する請求項２記載
のアルキル安息香酸の製造法3. The method for producing an alkylbenzoic acid according to claim 2, wherein water is continuously supplied to the oxidation reactor and heat is removed by azeotropic distillation of water and alkylbenzene.
調節することによる水とアルキルベンゼンを共沸により
除熱する請求項２記載のアルキル安息香酸の製造法4. The method for producing an alkylbenzoic acid according to claim 2, wherein the water and the alkylbenzene are azeotropically removed by adjusting the amount of the water phase removed from the condensed reflux liquid of the boiling vapor.
Priority Applications (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7285116A JPH09124549A (en) | 1995-11-01 | 1995-11-01 | Production of alkylbenzoic acid |
| US08/732,606 US5731466A (en) | 1995-11-01 | 1996-10-16 | Method for preparing alkylbenzoic acid |
| CN96122760A CN1063169C (en) | 1995-11-01 | 1996-10-30 | Method for preparing alkylbenzoic acid |
| CA002189185A CA2189185C (en) | 1995-11-01 | 1996-10-30 | Method for preparing alkylbenzoic acid |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7285116A JPH09124549A (en) | 1995-11-01 | 1995-11-01 | Production of alkylbenzoic acid |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH09124549A true JPH09124549A (en) | 1997-05-13 |
Family
ID=17687331
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP7285116A Pending JPH09124549A (en) | 1995-11-01 | 1995-11-01 | Production of alkylbenzoic acid |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH09124549A (en) |
-
1995
- 1995-11-01 JP JP7285116A patent/JPH09124549A/en active Pending
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