JPH0560470B2 - - Google Patents
Info
- Publication number
- JPH0560470B2 JPH0560470B2 JP60054257A JP5425785A JPH0560470B2 JP H0560470 B2 JPH0560470 B2 JP H0560470B2 JP 60054257 A JP60054257 A JP 60054257A JP 5425785 A JP5425785 A JP 5425785A JP H0560470 B2 JPH0560470 B2 JP H0560470B2
- Authority
- JP
- Japan
- Prior art keywords
- pyromellitic anhydride
- gas
- temperature
- solvent
- anhydride
- 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.)
- Expired - Lifetime
Links
- ANSXAPJVJOKRDJ-UHFFFAOYSA-N furo[3,4-f][2]benzofuran-1,3,5,7-tetrone Chemical compound C1=C2C(=O)OC(=O)C2=CC2=C1C(=O)OC2=O ANSXAPJVJOKRDJ-UHFFFAOYSA-N 0.000 claims description 54
- 238000000034 method Methods 0.000 claims description 26
- 238000002425 crystallisation Methods 0.000 claims description 10
- 230000008025 crystallization Effects 0.000 claims description 10
- -1 aromatic nitrile compound Chemical class 0.000 claims description 7
- 238000010438 heat treatment Methods 0.000 claims description 4
- 239000013078 crystal Substances 0.000 description 30
- JFDZBHWFFUWGJE-UHFFFAOYSA-N benzonitrile Chemical compound N#CC1=CC=CC=C1 JFDZBHWFFUWGJE-UHFFFAOYSA-N 0.000 description 27
- 239000002904 solvent Substances 0.000 description 27
- 239000007789 gas Substances 0.000 description 23
- 239000012495 reaction gas Substances 0.000 description 9
- 239000006227 byproduct Substances 0.000 description 6
- SRPWOOOHEPICQU-UHFFFAOYSA-N trimellitic anhydride Chemical compound OC(=O)C1=CC=C2C(=O)OC(=O)C2=C1 SRPWOOOHEPICQU-UHFFFAOYSA-N 0.000 description 6
- 238000000746 purification Methods 0.000 description 5
- 238000001816 cooling Methods 0.000 description 4
- FPYJFEHAWHCUMM-UHFFFAOYSA-N maleic anhydride Chemical compound O=C1OC(=O)C=C1 FPYJFEHAWHCUMM-UHFFFAOYSA-N 0.000 description 4
- 238000002844 melting Methods 0.000 description 4
- 239000003960 organic solvent Substances 0.000 description 4
- 238000001953 recrystallisation Methods 0.000 description 4
- 239000002253 acid Substances 0.000 description 3
- 238000004458 analytical method Methods 0.000 description 3
- 230000003197 catalytic effect Effects 0.000 description 3
- 238000006243 chemical reaction Methods 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 230000036571 hydration Effects 0.000 description 3
- 238000006703 hydration reaction Methods 0.000 description 3
- 230000008018 melting Effects 0.000 description 3
- 230000003647 oxidation Effects 0.000 description 3
- 238000007254 oxidation reaction Methods 0.000 description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 3
- 239000003054 catalyst Substances 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000001035 drying Methods 0.000 description 2
- SQNZJJAZBFDUTD-UHFFFAOYSA-N durene Chemical compound CC1=CC(C)=C(C)C=C1C SQNZJJAZBFDUTD-UHFFFAOYSA-N 0.000 description 2
- 238000004811 liquid chromatography Methods 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 230000001590 oxidative effect Effects 0.000 description 2
- CYIDZMCFTVVTJO-UHFFFAOYSA-N pyromellitic acid Chemical compound OC(=O)C1=CC(C(O)=O)=C(C(O)=O)C=C1C(O)=O CYIDZMCFTVVTJO-UHFFFAOYSA-N 0.000 description 2
- 239000000376 reactant Substances 0.000 description 2
- 238000011084 recovery Methods 0.000 description 2
- 238000007790 scraping Methods 0.000 description 2
- 238000000926 separation method Methods 0.000 description 2
- MYMOFIZGZYHOMD-UHFFFAOYSA-N Dioxygen Chemical compound O=O MYMOFIZGZYHOMD-UHFFFAOYSA-N 0.000 description 1
- 239000004642 Polyimide Substances 0.000 description 1
- OFOBLEOULBTSOW-UHFFFAOYSA-N Propanedioic acid Natural products OC(=O)CC(O)=O OFOBLEOULBTSOW-UHFFFAOYSA-N 0.000 description 1
- 229910010413 TiO 2 Inorganic materials 0.000 description 1
- 150000007513 acids Chemical class 0.000 description 1
- 150000008064 anhydrides Chemical class 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 238000009835 boiling Methods 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 229910001882 dioxygen Inorganic materials 0.000 description 1
- 238000004821 distillation Methods 0.000 description 1
- 238000005265 energy consumption Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 239000003822 epoxy resin Substances 0.000 description 1
- 150000002170 ethers Chemical class 0.000 description 1
- 238000007710 freezing Methods 0.000 description 1
- 230000008014 freezing Effects 0.000 description 1
- 238000004868 gas analysis Methods 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- LNEPOXFFQSENCJ-UHFFFAOYSA-N haloperidol Chemical compound C1CC(O)(C=2C=CC(Cl)=CC=2)CCN1CCCC(=O)C1=CC=C(F)C=C1 LNEPOXFFQSENCJ-UHFFFAOYSA-N 0.000 description 1
- 229920006015 heat resistant resin Polymers 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 150000002576 ketones Chemical class 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- VZCYOOQTPOCHFL-UPHRSURJSA-N maleic acid Chemical compound OC(=O)\C=C/C(O)=O VZCYOOQTPOCHFL-UPHRSURJSA-N 0.000 description 1
- 239000011976 maleic acid Substances 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 150000002825 nitriles Chemical class 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 239000004014 plasticizer Substances 0.000 description 1
- 229920000647 polyepoxide Polymers 0.000 description 1
- 229920001721 polyimide Polymers 0.000 description 1
- 230000001376 precipitating effect Effects 0.000 description 1
- 239000000047 product Substances 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 238000005092 sublimation method Methods 0.000 description 1
- VZCYOOQTPOCHFL-UHFFFAOYSA-N trans-butenedioic acid Natural products OC(=O)C=CC(O)=O VZCYOOQTPOCHFL-UHFFFAOYSA-N 0.000 description 1
- 238000011144 upstream manufacturing Methods 0.000 description 1
- 238000005406 washing Methods 0.000 description 1
- 239000002912 waste gas Substances 0.000 description 1
Landscapes
- Heterocyclic Carbon Compounds Containing A Hetero Ring Having Oxygen Or Sulfur (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Description
【発明の詳細な説明】
＜産業上の利用分野＞
本発明は無水ピロメリツト酸の捕集方法に関す
る。詳しく述べると本発明は１，２，４，５−テ
トラアルキルベンゼンとくにデユレンを分子状酸
素含有ガスにより接触気相酸化して得られる無水
ピロメリツト酸含有の反応熱ガスから工業的に有
利に無水ピロメリツト酸を捕集し回収する方法に
関する。DETAILED DESCRIPTION OF THE INVENTION <Industrial Field of Application> The present invention relates to a method for collecting pyromellitic anhydride. Specifically, the present invention provides industrially advantageous production of pyromellitic anhydride from the hot reaction gas containing pyromellitic anhydride obtained by catalytic gas phase oxidation of 1,2,4,5-tetraalkylbenzene, particularly durene, with a molecular oxygen-containing gas. It relates to a method of collecting and recovering.
無水ピロメリツト酸はポリイミドなどの耐熱性
樹脂原料、エポキシ樹脂の耐熱性硬化剤や耐熱性
可塑剤の原料として近年重要な工業製品として注
目されつつある化合物である。 Pyromellitic anhydride is a compound that has recently been attracting attention as an important industrial product as a raw material for heat-resistant resins such as polyimide, heat-resistant curing agents for epoxy resins, and heat-resistant plasticizers.
＜従来の技術＞
通常、無水ピロメリツト酸は従来から１，２，
４，５−テトラアルキルベンゼンを接触気相酸化
してえられ、ガス状で無水ピロメリツト酸を含有
する300〜500℃の高温の熱ガスを冷却し、ガス中
の無水ピロメリツト酸を捕集し回収するプロセス
がとられている。具体的な捕集法としては、以下
のものが挙げられる。<Conventional technology> Usually, pyromellitic anhydride has traditionally been 1, 2,
This method is obtained by catalytic gas phase oxidation of 4,5-tetraalkylbenzene, and cools the hot gas at a temperature of 300 to 500°C containing pyromellitic anhydride in the gaseous state, and collects and recovers the pyromellitic anhydride in the gas. A process is being followed. Specific collection methods include the following.
反応ガスを結晶捕集器に導びき、そこで無水
ピロメリツト酸の露点以下の温度に冷却するこ
とにより無水ピロメリツト酸を結晶として捕集
する方法（特公昭47−18745号、特開昭54−
79245号公報など）。 A method of collecting pyromellitic anhydride in the form of crystals by guiding the reaction gas to a crystal collector and cooling it there to a temperature below the dew point of pyromellitic anhydride (Japanese Patent Publication No. 18745/1983, Japanese Patent Application Laid-Open No. 1874-1989)
Publication No. 79245, etc.).
反応ガスを一定の冷却条件下スクラバー塔な
どに導びき、溶媒と接触させて捕集したり、あ
るいはサイクロンを用いて結晶として捕集する
方法（米国特許第3353334号、特公昭44−1118
号公報明細書参照）。 A method in which the reaction gas is guided to a scrubber tower under certain cooling conditions, brought into contact with a solvent, and collected, or collected as crystals using a cyclone (U.S. Patent No. 3,353,334, Japanese Patent Publication No. 1118-1983)
(Refer to the specification of the publication).
そして、えられた無水ピロメリツト酸の精製法
としては、水や有機溶媒による再結晶法または洗
滌法がある（たとえば、特公昭43−19934号、同
45−11133号、同47−44214号、同44−20092号、
同45−4050号、同47−41893号、特開昭50−58024
号、同49−133348号公報参照）し、昇華法や蒸留
法もある（たとえば、特公昭45−4052号、同47−
21982号公報参照）。 The obtained pyromellitic anhydride can be purified by recrystallization with water or organic solvents or by washing (for example, Japanese Patent Publication No. 43-19934,
No. 45-11133, No. 47-44214, No. 44-20092,
No. 45-4050, No. 47-41893, JP-A-50-58024
There are also sublimation methods and distillation methods (for example, Japanese Patent Publications No. 45-4052 and No. 47-198).
(See Publication No. 21982).
＜本発明が解決しようとする問題点＞
反応ガスから無水ピロメリツト酸を捕集、精製
する方法において、上述方法のうち、溶媒を使わ
ないで結晶捕集し、それを昇華（蒸留）する精製
法は、無水ピロメリツト酸の融点が285〜287℃と
高いうえ、蒸気圧は1.5mmHg（250℃）と低いた
め、工業プロセスとしてはエネルギー消費の点か
ら採用はむずかしい。<Problems to be Solved by the Present Invention> Among the methods described above, in the method of collecting and purifying pyromellitic anhydride from a reaction gas, a purification method of collecting crystals without using a solvent and sublimating (distilling) them. Since the melting point of pyromellitic anhydride is as high as 285-287°C, and the vapor pressure is as low as 1.5 mmHg (250°C), it is difficult to adopt it as an industrial process due to energy consumption.
一方、溶媒を用いる方法のうちで結晶捕集器に
溶媒を用いる場合、捕集手段としては良いが、捕
集した無水ピロメリツト酸の結晶の回収とか溶媒
の選定が重要なポイントとなる。溶媒の選定では
安全性、回収効率などを考慮すべきである。溶媒
として、水を使用する場合、安全性については問
題ないが、無水ピロメリツト酸が有水化しピロメ
リツト酸となり精製工程において再び無水物とす
る必要が生じる。有機溶媒を用いると有水化を防
ぐことはできるが、これまで提案されているケト
ン類、エーテル類などの溶媒は無水ピロメリツト
酸の溶解度があまり大きくなく、取り扱い量が不
可避的に多くなる。従つて安全性やロスの点から
このような溶媒法では工業的使用の点で十分とは
言えない。 On the other hand, in the method using a solvent, when a solvent is used in a crystal collector, it is good as a collection means, but the important points are the recovery of the collected crystals of pyromellitic anhydride and the selection of the solvent. Safety, recovery efficiency, etc. should be considered when selecting a solvent. When water is used as a solvent, there is no problem with safety, but pyromellitic anhydride becomes hydrated and becomes pyromellitic acid, and it becomes necessary to convert it into an anhydride again in the purification process. Although it is possible to prevent hydration by using an organic solvent, the solubility of pyromellitic anhydride in the solvents proposed so far such as ketones and ethers is not very high, and the amount to be handled becomes unavoidably large. Therefore, in terms of safety and loss, such solvent methods are not sufficient for industrial use.
さらにスクラバーによる捕集法は、反応ガスが
高温であるため予め何らかの冷却操作が必要なう
え、廃ガス中へのロスが大きな問題となる。 Furthermore, in the collection method using a scrubber, since the reaction gas is at a high temperature, some kind of cooling operation is required in advance, and loss into the waste gas becomes a major problem.
＜問題点を解決するための手段＞
そこで、本発明者らは、結晶捕集後有機溶媒を
用いた再結晶による精製を実施する方法におい
て、結晶捕集器の操作条件すなわち、処理される
反応熱ガスの線速および冷却温度と得られる無水
ピロメリツト酸の純度および捕集効率との相関関
係について検討を加えた結果、特定の操作条件下
において反応熱ガス中の副生物である無水ピロメ
リツト酸、無水マレイン酸塔を晶出させることな
く無水ピロメリツト酸を選択的に分別結晶化でき
るという知見を得て、さらにこの晶出した無水ピ
ロメリツト酸の結晶を有機溶媒、特に芳香族ニト
リル化合物、好ましくはベンゾニトリルを用いて
溶解またはスラリー化せしめ結晶捕集器外へ取り
出し、続いて再結晶することによつて高純度無水
ピロメリツト酸が工業的に実施可能な方法で得ら
れることを見い出し、本発明を完成させた。<Means for Solving the Problems> Therefore, the present inventors have developed a method of performing purification by recrystallization using an organic solvent after crystal collection, in which the operating conditions of the crystal collector, that is, the reaction to be processed, are As a result of examining the correlation between the linear velocity and cooling temperature of the hot gas and the purity and collection efficiency of the obtained pyromellitic anhydride, we found that under specific operating conditions, pyromellitic anhydride, a byproduct in the hot reaction gas, We have obtained the knowledge that pyromellitic anhydride can be selectively crystallized without crystallizing the maleic anhydride column, and further, we have obtained the knowledge that pyromellitic anhydride can be selectively crystallized without crystallizing the maleic anhydride column. It was discovered that high purity pyromellitic anhydride can be obtained in an industrially practicable method by dissolving or slurrying it using nitrile, taking it out of the crystal collector, and then recrystallizing it, and completed the present invention. I let it happen.
即ち、本発明は無水ピロメリツト酸を含有する
高温ガスを結晶室に導びき、当該ガスをその線速
が0.1〜1.0ｍ／秒となるようにしつつ、冷却し、
かつ当該ガスの結晶室出口温度を50〜200℃の範
囲に調整して、無水ピロメリツト酸を選択的に晶
出させ、ついで芳香族ニトリル化合物を結晶室に
導入し、100〜190℃の範囲の温度に加熱すること
により析出した無水ピロメリツト酸を溶解して結
晶室から取り出すことを特徴とする捕集方法であ
る。 That is, the present invention introduces a high-temperature gas containing pyromellitic anhydride into a crystallization chamber, cools the gas while maintaining a linear velocity of 0.1 to 1.0 m/sec,
Then, the temperature at the exit of the crystallization chamber of the gas is adjusted to a range of 50 to 200°C to selectively crystallize pyromellitic anhydride, and then the aromatic nitrile compound is introduced into the crystallization chamber, and the temperature is adjusted to a range of 100 to 190°C. This collection method is characterized by dissolving the precipitated pyromellitic anhydride by heating it to a certain temperature and taking it out from the crystallization chamber.
以下、本発明の詳細を一実施態様を示した第１
図に基づいて説明する。 Below, the details of the present invention will be explained in the first embodiment showing one embodiment.
This will be explained based on the diagram.
１，２，４，５−テトラアルキルベンゼンを触
媒の存在下で酸素含有ガスにより、接触酸化して
えられる反応熱ガスをライン５により並列に配置
した結晶捕集器１に導びき無水ピロメリツト酸を
捕集し、未凝縮ガスはライン１０を通つて系外に
出される。この際、反応熱ガスの温度は無水ピロ
メリツト酸の露点以上であるが、充分高い場合に
は結晶捕集器１の上流側に熱交換器（図示せず）
を設置して、予め熱回収することができる。結晶
捕集器１は、当該ガスの線速が0.1〜1.0ｍ／秒と
なるように設計される。線速は大きすぎると析出
した無水ピロメリツト酸の結晶が飛散してしま
い、又、小さすぎると装置が大きくなちてしま
う。更に、結晶捕集器出口のガス温度は50〜200
℃、好ましくは100〜150℃となるように調整す
る。これは接触反応中に生じる副生物である無水
ピロメリツト酸、無水マレイン酸等の晶出を防
ぎ、かつ無水ピロメリツト酸の捕集率を大きくす
るためである。すなわち、温度が低いと捕集率は
大きいが、副生物も同時に捕集される。逆に高す
ぎると無水ピロメリツト酸の純度は高いが捕集率
が低くなる。このように本発明が特定する操作条
件を選定することにより、従来のように無水ピロ
メリツト酸の露点温度以下に一挙に落とし不純物
も共に析出させる方法と比較して、優れて高純度
の無水ピロメリツト酸が高収量でえられるのであ
る。 The hot reaction gas obtained by catalytically oxidizing 1,2,4,5-tetraalkylbenzene with an oxygen-containing gas in the presence of a catalyst is guided through a line 5 to a crystal collector 1 arranged in parallel to produce pyromellitic anhydride. The collected and uncondensed gas is discharged from the system through line 10. At this time, the temperature of the reaction hot gas is higher than the dew point of pyromellitic anhydride, but if it is sufficiently high, a heat exchanger (not shown) is installed upstream of the crystal collector 1.
can be installed to recover heat in advance. The crystal collector 1 is designed so that the linear velocity of the gas is 0.1 to 1.0 m/sec. If the linear velocity is too high, the precipitated crystals of pyromellitic anhydride will scatter, and if the linear velocity is too low, the device will become too large. Furthermore, the gas temperature at the outlet of the crystal collector is between 50 and 200℃.
℃, preferably 100 to 150℃. This is to prevent crystallization of pyromellitic anhydride, maleic anhydride, etc., which are by-products generated during the contact reaction, and to increase the collection rate of pyromellitic anhydride. That is, when the temperature is low, the collection rate is high, but by-products are also collected at the same time. On the other hand, if it is too high, the purity of pyromellitic anhydride will be high but the collection rate will be low. By selecting the operating conditions specified by the present invention in this manner, it is possible to produce pyromellitic anhydride with superior purity compared to the conventional method of dropping the temperature below the dew point temperature of pyromellitic anhydride and precipitating impurities as well. can be obtained in high yield.
一定時間反応ガスを通じた後、ライン５を切り
替え、一方の結晶捕集器に導びき、引き続き捕集
を行う。その間、捕集した捕集器には溶媒タンク
２よりライン６を通じて芳香族ニトリル化合物を
循環させ、無水ピロメリツト酸を溶解またはスラ
リー化させライン７を通して溶媒タンク２に回収
する。この時の操作温度は好ましくは100〜190℃
で行なわれる。回収の終つた捕集器は付着溶媒を
除去後、再び反応ガスを導びき捕集する。 After passing the reactant gas for a certain period of time, the line 5 is switched and guided to one of the crystal collectors for subsequent collection. During this time, the aromatic nitrile compound is circulated from the solvent tank 2 to the collector through line 6, and the pyromellitic anhydride is dissolved or slurried and collected into the solvent tank 2 through line 7. The operating temperature at this time is preferably 100-190℃
It will be held in After the collection is completed, the collector removes the adhering solvent and then guides and collects the reaction gas again.
一般に結晶捕集方法は晶出した結晶を取り出す
ために、冷却器壁面に晶出した結晶をかき取る
か、加熱溶融して取り出すといつた操作が採用さ
れているが、本発明が取り扱う無水ピロメリツト
酸は前述のように高融点（285〜287℃）であるた
め加熱溶融方法ではそのエネルギー損失が大きい
し、また変質しやすいので適用が困難である。ま
たかき取り方法では、多大の労力と設備を必要と
するので経済的に不利である。そこで本発明にお
いては上述のように晶出した結晶を取り出すため
に、芳香族ニトリル化合物好ましくはベンゾニト
リルに溶解またはスラリー化させる方法を採用す
ることによつて従来の問題点を解決し、引き続い
て再結晶するか単に溶媒を除去することによつて
有水化させることなく高純度の無水ピロメリツト
酸が容易に得られるのである。特にベンゾニトリ
ルは第２図に示した如く無水ピロメリツト酸の優
れた溶媒であるために、結晶捕集器からの取り出
しにおいても、続いて行なわれる再結晶において
も他の溶媒と比較してその使用量を少なくするこ
とができる。 In general, crystal collection methods employ operations such as scraping off the crystals that have formed on the wall of a cooler or heating and melting them to take out the crystals, but the anhydrous pyromellits handled by the present invention As mentioned above, acids have a high melting point (285 to 287° C.), so the heat-melting method causes a large energy loss and is easy to change in quality, making it difficult to apply. Furthermore, the scraping method requires a great deal of labor and equipment, and is therefore economically disadvantageous. Therefore, in the present invention, in order to take out the crystals crystallized as described above, the conventional problems are solved by adopting a method of dissolving or slurrying an aromatic nitrile compound, preferably benzonitrile, and then High purity pyromellitic anhydride can be easily obtained without hydration by recrystallization or simply removing the solvent. In particular, benzonitrile is an excellent solvent for pyromellitic anhydride as shown in Figure 2, so its use is better compared to other solvents both in taking it out of the crystal collector and in the subsequent recrystallization. The amount can be reduced.
結晶捕集器１より回収した無水ピロメリツト酸
は、溶媒タンク２において完全に溶解せしめた
後、晶析器３により析出させ分離・乾燥器４で無
水ピロメリツト酸を得る。分離された溶媒は再び
ライン９により溶媒タンク２に送り再使用され
る。この工程で結晶効果があり、更に純度は高め
られる。 The pyromellitic anhydride collected from the crystal collector 1 is completely dissolved in the solvent tank 2, and then precipitated in the crystallizer 3, and then in the separation/dryer 4 to obtain pyromellitic anhydride. The separated solvent is again sent to the solvent tank 2 via line 9 and reused. This process has a crystallization effect and further increases purity.
実施例 １
デユレン（１，２，４，５−テトラアルキルベ
ンゼン）をV2O5−TiO2系触媒の存在下空気によ
り接触酸化して得た反応ガスを、外部をヒーター
で保温した30mm〓×1000mmLのガラス製捕集器に導
びき、その出口ガスの温度が120℃になるように
ヒーターでコントロールした。ガス分析の結果、
入口ガスは重量比で無水ピロメリツト酸100に対
し、無水トリメリツト酸５、無水マレイン酸３、
その他３を含有し、出口ガスは同様に１：３：
３：2.5を含有していた。反応ガスを10／Ｍで
30分間通した（ガス線速0.24メートル／秒）後、
捕集管には白色の針状結晶が５ｇ得られた。液状
クロマトグラフイーにより分析したところ無水ピ
ロメリツト酸97.5％、無水トリメリツト酸2.0％、
その他0.5％含んでいた。Example 1 A reaction gas obtained by catalytically oxidizing Duurene (1,2,4,5-tetraalkylbenzene) with air in the presence of a V 2 O 5 -TiO 2 catalyst was heated in a 30 mm × The gas was led to a 1000 mm L glass collector, and the temperature of the exit gas was controlled to 120°C using a heater. As a result of gas analysis,
The inlet gas has a weight ratio of 100% pyromellitic anhydride to 5% trimellitic anhydride, 3% maleic anhydride,
Contains other 3, and the outlet gas is similarly 1:3:
It contained 3:2.5. Reactant gas at 10/M
After passing for 30 minutes (gas linear velocity 0.24 m/s),
5 g of white needle-like crystals were obtained in the collection tube. Analysis by liquid chromatography revealed that pyromellitic anhydride was 97.5%, trimellitic anhydride 2.0%,
Others included 0.5%.
このようにして得た無水ピロメリツト酸の結晶
100ｇをベンゾニトリル200ｇに加え150℃に加温
したところ全て溶解し、かつ無色透明の溶液とな
つた。次に室温まで冷却し、析出した白色結晶を
吸引ろ過し、付着溶媒を乾燥除去したところ結晶
96ｇを得た。分析の結果、無水ピロメリツト酸
95.5ｇ（含有率99.5％）、無水トリメリツト酸を
0.2ｇ（同0.2％）含み酸価は1026mgKOH／ｇ
Sampleであつた。 Crystals of pyromellitic anhydride obtained in this way
When 100g of the solution was added to 200g of benzonitrile and heated to 150°C, it completely dissolved and became a colorless and transparent solution. Next, it was cooled to room temperature, the precipitated white crystals were suction-filtered, and the attached solvent was removed by drying, resulting in crystals.
Obtained 96g. As a result of analysis, pyromellitic anhydride
95.5g (99.5% content) of trimellitic anhydride
Contains 0.2g (0.2%) and has an acid value of 1026mgKOH/g
It was Sample.
比較例 １
捕集管の出口ガス温度を40℃とした以外は実施
例１におけると同様に行なつた、ガスを10／Ｍ
で30分間通じた後捕集管には5.3ｇ捕集されてい
た。これを液体クロマトグラフイーにより分析し
たところ、無水ピロメリツト酸92.6％、無水トリ
メリツト酸4.6％、その他2.8％を含んでいた。Comparative Example 1 The same procedure as in Example 1 was carried out except that the gas temperature at the outlet of the collection tube was 40°C.
After 30 minutes, 5.3g was collected in the collection tube. When this was analyzed by liquid chromatography, it contained 92.6% of pyromellitic anhydride, 4.6% of trimellitic anhydride, and 2.8% of others.
このようにして得た無水ピロメリツト酸の結晶
100ｇをベンゾニトリル200ｇに加え、150℃に加
温したところ全て溶解し黒かつ色透明の溶液とな
つた。次に室温まで冷却し析出した淡かつ色がか
つた白色結晶を吸引ろ過し付着溶媒を過したと
ころ結晶95ｇを得た。分析の結果、無水ピロメリ
ツト酸94ｇ（99.0％）。無水トリメリツト酸0.7ｇ
（0.7％）、その他0.3ｇ（0.3％）含有していた。酸
価は1024mgKOH／ｇ Sampleであつた。 Crystals of pyromellitic anhydride obtained in this way
When 100g of the solution was added to 200g of benzonitrile and heated to 150°C, everything dissolved to form a black and transparent solution. Next, the mixture was cooled to room temperature, and the precipitated pale and discolored white crystals were suction-filtered to remove the adhesion solvent, yielding 95 g of crystals. As a result of analysis, 94g (99.0%) of pyromellitic anhydride. Trimellitic anhydride 0.7g
(0.7%) and 0.3g (0.3%) of others. The acid value was 1024 mgKOH/g Sample.
参考例
無水ピロメリツト酸のベンゾニトリルに対する
各温度における溶解度を測定した。結果を第２図
に示す。Reference Example The solubility of pyromellitic anhydride in benzonitrile at various temperatures was measured. The results are shown in Figure 2.
＜発明の効果＞
以上の実施例および参考例からも明らかなよう
に、本発明は次にような効果を有する。<Effects of the Invention> As is clear from the above Examples and Reference Examples, the present invention has the following effects.
１ 本発明が特定する捕集条件である線速を0.1
〜1.0メートル／秒かつ捕集器出口温度を50〜
200℃、好ましくは100〜150℃にすることによ
り副生物をカツトし、選択的に無水ピロメリツ
ト酸を捕集でき、しかも捕集効率が高い。すな
わち精製工程の簡略化が可能である。1 The linear velocity, which is the collection condition specified by the present invention, is set to 0.1
~1.0m/sec and collector outlet temperature 50~
By heating the temperature to 200°C, preferably 100 to 150°C, by-products can be removed and pyromellitic anhydride can be selectively collected, and the collection efficiency is high. That is, the purification process can be simplified.
２ 有機溶媒として芳香族ニトリル化合物、特に
ベンゾニトリルを使用する場合、ベンゾニトリ
ルは第２図に示すように、無水ピロメリツト酸
の溶媒としてこれまで提示されたいかなる溶媒
より大きな溶解度と温度による溶解度差を示
す、非常に適した溶媒である。このことにより
取り扱い量が少なくてすみ、かつ沸点191℃凝
固点−13℃と広い範囲で液体であることで溶媒
導入時の捕集器温度範囲が広い。一方、結晶の
分離も粘度が低くスムーズに行なえる。2 When an aromatic nitrile compound, especially benzonitrile, is used as an organic solvent, as shown in Figure 2, benzonitrile has a greater solubility and a temperature-dependent solubility difference than any other solvent proposed so far as a solvent for pyromellitic anhydride. It is a very suitable solvent. As a result, the amount to be handled is small, and since it is a liquid over a wide range of boiling point of 191°C and freezing point of -13°C, the temperature range of the collector when introducing the solvent is wide. On the other hand, the crystals can be separated smoothly due to the low viscosity.
３ 溶媒が水分をほとんど含まないため、回収し
た無水ピロメリツト酸の有水化がほとんど無
い。3. Since the solvent contains almost no water, there is almost no hydration of the recovered pyromellitic anhydride.
４ 通常、１，２，４，５−テトラアルキルベン
ゼンの接触酸化では、無水トリメリツト酸、マ
レイン酸等た一部副生する。そのほとんどは捕
集器の出口ガス温度を調節することにより分離
されるが、一部は、無水ピロメリツト酸中に混
入する。芳香族ニトリル化合物、特にベンゾニ
トリルはこれらの副生物に対しても良好の溶解
度を示し、精製溶媒としても適してきる。4 Usually, in the catalytic oxidation of 1,2,4,5-tetraalkylbenzene, some by-products such as trimellitic anhydride and maleic acid are produced. Most of it is separated by adjusting the outlet gas temperature of the collector, but some of it is mixed into the pyromellitic anhydride. Aromatic nitrile compounds, especially benzonitrile, exhibit good solubility for these by-products and are also suitable as purification solvents.
第１図は本発明方法の一実施態様を示すプロセ
ス図であり、第２図は無水ピロメリツト酸のベン
ゾニトリルに対する溶解度を示すグラフである。
１……結晶捕集器、２……溶媒タンク、３……
晶析器、４……分離・乾燥器。
FIG. 1 is a process diagram showing one embodiment of the method of the present invention, and FIG. 2 is a graph showing the solubility of pyromellitic anhydride in benzonitrile. 1...Crystal collector, 2...Solvent tank, 3...
Crystallizer, 4... Separation/drying device.
Claims (1)
晶室に導びき、当該ガスをその線速が0.1〜1.0メ
ートル／秒となるようにしつつ冷却し、かつ当該
ガスの結晶室出口温度を50〜200℃の範囲に調整
して無水ピロメリツト酸を選択的に晶出させ、つ
いで芳香族ニトリル化合物を結晶室に導入し、
100〜190℃の範囲の温度に加熱することによつて
析出した無水ピロメリツト酸を溶解して結晶室か
ら取出すことを特徴とする無水ピロメリツト酸の
捕集方法。1. Guide high-temperature gas containing pyromellitic anhydride to a crystallization chamber, cool the gas while maintaining a linear velocity of 0.1 to 1.0 meters/second, and keep the temperature of the gas at the exit of the crystallization chamber from 50 to 200°C. to selectively crystallize pyromellitic anhydride, and then introduce an aromatic nitrile compound into the crystallization chamber.
1. A method for collecting pyromellitic anhydride, which comprises heating the precipitated pyromellitic anhydride to a temperature in the range of 100 to 190°C to dissolve the precipitated pyromellitic anhydride and take it out from the crystallization chamber.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP60054257A JPS61215352A (en) | 1985-03-20 | 1985-03-20 | Collection of pyromellitic anhydride |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP60054257A JPS61215352A (en) | 1985-03-20 | 1985-03-20 | Collection of pyromellitic anhydride |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| JPS61215352A JPS61215352A (en) | 1986-09-25 |
| JPH0442389B2 JPH0442389B2 (en) | 1992-07-13 |
| JPH0560470B2 true JPH0560470B2 (en) | 1993-09-02 |
Family
ID=12965501
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP60054257A Granted JPS61215352A (en) | 1985-03-20 | 1985-03-20 | Collection of pyromellitic anhydride |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS61215352A (en) |
-
1985
- 1985-03-20 JP JP60054257A patent/JPS61215352A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS61215352A (en) | 1986-09-25 |
| JPH0442389B2 (en) | 1992-07-13 |
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