JP4022929B2 - Method for producing 3,5-bis (trifluoromethyl) nitrobenzene - Google Patents
Method for producing 3,5-bis (trifluoromethyl) nitrobenzene Download PDFInfo
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- JP4022929B2 JP4022929B2 JP18696095A JP18696095A JP4022929B2 JP 4022929 B2 JP4022929 B2 JP 4022929B2 JP 18696095 A JP18696095 A JP 18696095A JP 18696095 A JP18696095 A JP 18696095A JP 4022929 B2 JP4022929 B2 JP 4022929B2
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- trifluoromethyl
- bis
- sulfuric acid
- btfb
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- GMUWJDVVXLBMEZ-UHFFFAOYSA-N 1-nitro-3,5-bis(trifluoromethyl)benzene Chemical compound [O-][N+](=O)C1=CC(C(F)(F)F)=CC(C(F)(F)F)=C1 GMUWJDVVXLBMEZ-UHFFFAOYSA-N 0.000 title claims description 8
- 238000004519 manufacturing process Methods 0.000 title claims description 4
- 238000006243 chemical reaction Methods 0.000 claims description 40
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 claims description 16
- AKEJUJNQAAGONA-UHFFFAOYSA-N sulfur trioxide Chemical compound O=S(=O)=O AKEJUJNQAAGONA-UHFFFAOYSA-N 0.000 claims description 16
- 239000002904 solvent Substances 0.000 claims description 15
- 229910017604 nitric acid Inorganic materials 0.000 claims description 14
- 239000002994 raw material Substances 0.000 claims description 12
- HIFJUMGIHIZEPX-UHFFFAOYSA-N sulfuric acid;sulfur trioxide Chemical compound O=S(=O)=O.OS(O)(=O)=O HIFJUMGIHIZEPX-UHFFFAOYSA-N 0.000 claims description 11
- SJBBXFLOLUTGCW-UHFFFAOYSA-N 1,3-bis(trifluoromethyl)benzene Chemical compound FC(F)(F)C1=CC=CC(C(F)(F)F)=C1 SJBBXFLOLUTGCW-UHFFFAOYSA-N 0.000 claims description 7
- 238000006396 nitration reaction Methods 0.000 claims description 7
- 239000000203 mixture Substances 0.000 claims 1
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 14
- 239000000047 product Substances 0.000 description 10
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 10
- 238000000034 method Methods 0.000 description 9
- WSLDOOZREJYCGB-UHFFFAOYSA-N 1,2-Dichloroethane Chemical compound ClCCCl WSLDOOZREJYCGB-UHFFFAOYSA-N 0.000 description 6
- 239000002253 acid Substances 0.000 description 5
- 238000003756 stirring Methods 0.000 description 5
- 239000000243 solution Substances 0.000 description 4
- 239000000126 substance Substances 0.000 description 4
- IMNFDUFMRHMDMM-UHFFFAOYSA-N N-Heptane Chemical compound CCCCCCC IMNFDUFMRHMDMM-UHFFFAOYSA-N 0.000 description 3
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 3
- 239000006227 byproduct Substances 0.000 description 3
- 238000007086 side reaction Methods 0.000 description 3
- QPFMBZIOSGYJDE-UHFFFAOYSA-N 1,1,2,2-tetrachloroethane Chemical compound ClC(Cl)C(Cl)Cl QPFMBZIOSGYJDE-UHFFFAOYSA-N 0.000 description 2
- 230000002378 acidificating effect Effects 0.000 description 2
- 239000003795 chemical substances by application Substances 0.000 description 2
- 230000000052 comparative effect Effects 0.000 description 2
- 238000001816 cooling Methods 0.000 description 2
- 238000004817 gas chromatography Methods 0.000 description 2
- 239000010410 layer Substances 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- VLKZOEOYAKHREP-UHFFFAOYSA-N n-Hexane Chemical compound CCCCCC VLKZOEOYAKHREP-UHFFFAOYSA-N 0.000 description 2
- 239000012044 organic layer Substances 0.000 description 2
- 239000003960 organic solvent Substances 0.000 description 2
- -1 polyoxyethylene Polymers 0.000 description 2
- 230000009257 reactivity Effects 0.000 description 2
- 238000006277 sulfonation reaction Methods 0.000 description 2
- NHGXDBSUJJNIRV-UHFFFAOYSA-M tetrabutylammonium chloride Chemical compound [Cl-].CCCC[N+](CCCC)(CCCC)CCCC NHGXDBSUJJNIRV-UHFFFAOYSA-M 0.000 description 2
- 238000001644 13C nuclear magnetic resonance spectroscopy Methods 0.000 description 1
- 238000005160 1H NMR spectroscopy Methods 0.000 description 1
- 229920003171 Poly (ethylene oxide) Polymers 0.000 description 1
- 239000003905 agrochemical Substances 0.000 description 1
- 125000001931 aliphatic group Chemical group 0.000 description 1
- 150000001338 aliphatic hydrocarbons Chemical class 0.000 description 1
- 239000007864 aqueous solution Substances 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 238000009835 boiling Methods 0.000 description 1
- 239000012043 crude product Substances 0.000 description 1
- 239000003814 drug Substances 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 150000002170 ethers Chemical class 0.000 description 1
- 230000020169 heat generation Effects 0.000 description 1
- 229930195733 hydrocarbon Natural products 0.000 description 1
- 150000002430 hydrocarbons Chemical class 0.000 description 1
- 230000007062 hydrolysis Effects 0.000 description 1
- 238000006460 hydrolysis reaction Methods 0.000 description 1
- DWTYPCUOWWOADE-UHFFFAOYSA-M hydron;tetramethylazanium;sulfate Chemical compound C[N+](C)(C)C.OS([O-])(=O)=O DWTYPCUOWWOADE-UHFFFAOYSA-M 0.000 description 1
- 238000004811 liquid chromatography Methods 0.000 description 1
- 239000011259 mixed solution Substances 0.000 description 1
- 230000000802 nitrating effect Effects 0.000 description 1
- 239000003444 phase transfer catalyst Substances 0.000 description 1
- 238000011002 quantification Methods 0.000 description 1
- 230000035484 reaction time Effects 0.000 description 1
- 238000011084 recovery Methods 0.000 description 1
- APSBXTVYXVQYAB-UHFFFAOYSA-M sodium docusate Chemical compound [Na+].CCCCC(CC)COC(=O)CC(S([O-])(=O)=O)C(=O)OCC(CC)CCCC APSBXTVYXVQYAB-UHFFFAOYSA-M 0.000 description 1
- 239000000758 substrate Substances 0.000 description 1
- 238000003786 synthesis reaction Methods 0.000 description 1
Landscapes
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Description
【０００１】
【産業上の利用分野】
本発明は、以下の反応で示される３，５−ビス（トリフルオロメチル）ニトロベンゼンの製造法に関する。
【０００２】
【化１】
３，５−ビス（トリフルオロメチル）ニトロベンゼン（以下、ＢＴＦＮＢと略記する。）は、近年医薬・農薬等に代表される有機化学品の中間体として重要になって来ている。
【０００４】
【従来の技術】
これまでの文献（ジャーナル・オブ・ザ・アメリカン・ケミカル・ソサイヤティー ７５巻 ４９６７頁 １９５３年）で知られている方法は、１，３−ビス（トリフルオロメチル）ベンゼン（以下、ＢＴＦＢと略記する。）は、反応性が極めて低いために、２４％発煙硫酸という強酸を溶媒として、１００％硝酸をＢＴＦＢに対し６．７当量用いて９０〜１０５℃で反応を行いＢＴＦＮＢ收率６６．５％の結果であった。この方法は、まず、原料中に硫酸を滴下し、その混合液中に硝酸を滴下するために、混酸生成時に生じる高い発熱によって原料のニトロ化及び副反応を誘発しさらにその反応熱も加わって、反応規模が増大する実用場面では、反応制御がむずかしい欠点を有している。
【０００５】
また、２０％以上の発煙硫酸を１００℃付近で用いることによるスルホン化等の副反応が大きくなりＢＴＦＢ收率を低下させている。
さらに１００℃以上まで昇温させることによる硝酸の飛散により、使用する硝酸量は、原料ＢＴＦＢに対し６．７当量にも及び、工業的には、問題が多い。
【０００６】
【発明が解決しようとする課題】
反応温度制御をしながら、低硝酸量で高ＢＴＦＮＢ收率を得る反応条件の探索を課題として研究の結果本発明を完成した。本発明の目的は１，３−ビス（トリフルオロメチル）ベンゼン（ＢＴＦＢ）より高収率で得る３，５−ビス（トリフルオロメチル）ニトロベンゼン（ＢＴＦＮＢ）の製造法の提供にある。
【０００７】
【課題を解決するための手段】
本発明は、１，３−ビス（トリフルオロメチル）ベンゼンの硝酸によるニトロ化方法に於て、溶媒として９１％以上の濃度の硫酸又は、三酸化硫黄濃度が２０％以下の発煙硫酸を用いて、反応温度５０〜１００℃の温度範囲で反応させることを特徴とする３，５−ビス（トリフルオロメチル）ニトロベンゼンの製造法に関する。
【０００８】
以下、本発明を詳細に説明する。
【０００９】
【発明の実施形態】
原料の１，３−ビス（トリフルオロメチル）ベンゼンは、通常入手できる純度のものをそのまま使用できる。
本発明の第１の特徴は溶媒の選択にある。本反応を促進させるためには強酸性溶媒が必須である。又、同時に加水分解等の副反応を抑制するために含水量が少ないことが好ましい。従って、硝酸によるニトロ化で副生する水を強酸の硫酸に変えてくれる三酸化硫黄を含有する発煙硫酸が、ふさわしい溶媒として挙げることができる。
【００１０】
しかし、本発明者は、この三酸化硫黄含有濃度について詳細に検討した結果、高濃度になるとスルホン化物の副生が多くなることを見出した。従って発煙硫酸中の三酸化硫黄の好ましい濃度は２０％以下であり、より好ましくは１０％以下が、高いＢＴＦＮＢ收率を与えることを見出した。
さらに、フリーの三酸化硫黄を含まない濃硫酸のみを溶媒として使用しても充分高收率でＢＴＦＮＢが得られることを、新たに見出した。
【００１１】
硫酸濃度は、９１％以上１００％以下が好ましく、取扱い容易な市販の９７％濃硫酸そのものでも可能である。９１％未満の濃度になると反応が急激に遅くなる。
その使用量は、原料ＢＴＦＢに対し１〜２０重量倍が好ましく、特には、２〜１０重量倍が望ましい。原料ＢＴＦＢのこれらの溶媒への溶解度は、小さいことから溶媒量が多い方が反応は促進される。
【００１２】
一方、ニトロ化剤としての硝酸は、前述の理由から含水量ができるだけ少ない方が好ましい。ただし含水品の場合も、三酸化硫黄又は発煙硫酸の添加量を増加させれば同様に使用することができる。一般に入手できる９４％又は９８％の発煙硝酸をそのまま使用することができる。硝酸量は、原料ＢＴＦＢの反応性が低いところから、転化率を上げるためには、原料に対し当量以上を使用する必要がある。
【００１３】
硝酸量が多ければ、反応が速くなるが、反応後の余剰硝酸の回収の煩雑さから原料ＢＴＦＢに対し５倍当量以下好ましくは４倍当量以内で行うのが好ましい。本発明では、各反応資材の仕込み順序及び最適反応温度の検討により、硝酸量が１．５〜２倍当量程度でも高いＢＴＦＮＢ收率が得られることを見出した。（文献例：６．７倍）
本発明の第２の特徴は、最適反応温度にある。発煙硫酸又は濃硫酸を溶媒としてニトロ化する場合、基質によって高温ではスルホン化が併発する。ＢＴＦＢは、９０℃付近からスルホン化物が副生する。
【００１４】
従って、高濃度の発煙硫酸を溶媒とする場合は、低温領域で反応させる必要がある。発煙硫酸及び濃硫酸溶媒で、目的生成物ＢＴＦＮＢ反応收率８０％以上の温度範囲を詳細に検討した結果好ましくは５０℃〜１００℃，特には、６０〜９５℃間であることを見出した。
本発明の第３の特徴は、各反応資材の仕込み方法である。反応制御の操作性及び目的生成物の選択性の面から混酸合成で生じる発熱とニトロ化反応で生成する発熱を分離し温度制御することが好ましい。
【００１５】
ＢＴＦＢは、モノニトロ化の後、ジニトロ化の心配がないところから、あらかじめ合成した混酸中に、反応させながらＢＴＦＢを時間をかけて滴下又は分割投入する方法が好ましい。この方法により、ニトロ化反応の発熱のみの除熱又は、保温の操作で良いことになり反応温度制御が容易になる。
ＢＴＦＢの滴下時間又は分割回数は、反応規模や反応装置によって異なる。本反応では、前述の無機強酸性溶媒に加え有機溶媒を使用することもできる。使用できる溶媒としては、１，２−ジクロルエタン及び１，１，２，２−テトラクロルエタン等に代表されるハロゲン化脂肪族炭化水素類やｎ−ヘキサン及びｎ−ヘプタン等に代表される脂肪族炭化水素類等が挙げられる。
【００１６】
その使用量は、原料ＢＴＦＢに対し０．５〜２０重量倍、特には１〜１０重量倍が好ましい。
本反応は２層反応であるところからジ（２−エチルヘキシル）スルホコハク酸ナトリウムに代表される各種のアルキルスルホコハク酸塩、ポリオキシエチレンノニルフェニルエーテルに代表されるポリオキシエチレンアルキルアリルエーテル等の界面活性剤やテトラブチルアンモニウムクロライド及びテトラメチルアンモニウムハイドロジェンサルフェート等に代表される相間移動触媒等を使用し、反応を促進させることもできる。
【００１７】
その使用量は、原料ＢＴＦＢに対し０．１〜１０モル％が適当である。
反応時間は、反応条件によって異なりガスクロマトグラフィー又は液体クロマトグラフィー等により反応液を分析することによって決定できる。
反応後は、冷却し室温に戻すと生成物は油層として分離する。これをそのまま分離することができる。又有機溶媒で抽出することもできる。これらを水洗後、アルカリ水溶液で洗浄し、もう一度水洗すると、スルホン化物や分解物等の副生物は、除去される。
【００１８】
さらにこの粗物を蒸留することにより目的とするＢＴＦＢの高純度品が得られる。
以下実施例をもって本発明を更に具体的に説明するが、これらによって本発明は限定されるものではない。
【００１９】
【実施例】
実施例１
９７％硫酸１６０ｇを四口反応フラスコに仕込み、その氷冷撹拌下に、９４％発煙硝酸２０．１ｇを１時間かけて滴下した。続いて反応器を８５℃迄昇温させた後、その撹拌下に１，３−ビス（トリフルオロメチル）ベンゼン（ＢＴＦＢ）３２．１ｇ（０．１５ｍｌ）を２時間かけて滴下した。その後同じ温度で３時間撹拌を継続し反応を停止し冷却した。
【００２０】
続いて、１，２−ジクロルエタン（ＥＤＣ）３２ｇ２回で生成物を抽出した。
この有機層を水洗、１０％水酸化ナトリウム水溶液洗浄さらに水洗と繰り返した後濃縮・蒸留した。主留分として沸点７１〜７２℃／９３３Ｐａの油状物質３１．１ｇを得た。
この留分をガスクロマトグラフィーで分析すると９９％の純度であった。さらにＭＡＳＳ，1 Ｈ−ＮＭＲ及び13Ｃ−ＮＭＲから目的とする３，５−ビス（トリフルオロメチル）ニトロベンゼン（ＢＴＦＮＢ）であることが判明した。
【００２１】
上記ＥＤＣ溶液を定量した結果ＢＴＦＮＢ反応收率は８５．１％であった。
【００２２】
実施例２〜７，比較例１〜５
実施例１に於て、溶媒、温度、時間を換えた他は、同様に反応を行い、反応終了後、ＥＤＣ抽出した有機層について定量した結果を次表に示す。
【００２３】
【表１】
比較例５
実施例１に於てＢＴＦＢ３２．１ｇを一括仕込み、反応を開始したところ、約１０分後に発熱が見られ反応温度は、９３℃以上に昇温した。そこで油浴をはずし、水浴で冷却した。
８５℃に戻ったところで、水浴をはずし、空冷下撹拌を続けた。しばらく発熱が続いた後８５℃以下になって来たところで再び油浴につけ、８５℃を保った。合計４時間撹拌し反応を終了させた。反応液を冷却後ＥＤＣで抽出し、定量を行った結果、ＢＴＦＮＢ收率は、６６．２％であった。
【００２５】
【発明の効果】
表に示すように本発明方法によると３，５−ビス（トリフルオロメチル）ニトロベンゼン（ ＢＴＦＮＢ）の収率が高い。[0001]
[Industrial application fields]
The present invention relates to a method for producing 3,5-bis (trifluoromethyl) nitrobenzene represented by the following reaction.
[0002]
[Chemical 1]
3,5-bis (trifluoromethyl) nitrobenzene (hereinafter abbreviated as BTFNB) has recently become important as an intermediate for organic chemicals represented by pharmaceuticals and agricultural chemicals.
[0004]
[Prior art]
The method known in the previous literature (Journal of the American Chemical Society 75, 4967, 1953) is abbreviated as 1,3-bis (trifluoromethyl) benzene (hereinafter referred to as BTFB). ) Is extremely low in reactivity, and the reaction was carried out at 90 to 105 ° C. using 6.7 equivalents of 100% nitric acid with respect to BTFB using a strong acid of 24% fuming sulfuric acid as a solvent, and a BTFNB yield of 66.5%. It was a result. In this method, first, sulfuric acid is dropped into the raw material, and nitric acid is dropped into the mixed solution. Therefore, nitration and side reactions of the raw material are induced by the high exotherm generated when the mixed acid is generated, and the heat of reaction is also added. In practical situations where the reaction scale increases, reaction control is difficult.
[0005]
Further, side reactions such as sulfonation due to the use of 20% or more of fuming sulfuric acid at around 100 ° C. are increased, and the BTFB yield is reduced.
Furthermore, due to the scattering of nitric acid by raising the temperature to 100 ° C. or higher, the amount of nitric acid used is 6.7 equivalents relative to the raw material BTFB, and there are many problems in the industry.
[0006]
[Problems to be solved by the invention]
The present invention was completed as a result of research on the search of reaction conditions for obtaining a high BTFNB yield with a low amount of nitric acid while controlling the reaction temperature. An object of the present invention is to provide a process for producing 3,5-bis (trifluoromethyl) nitrobenzene (BTNFNB) obtained in a higher yield than 1,3-bis (trifluoromethyl) benzene (BTFB).
[0007]
[Means for Solving the Problems]
The present invention relates to a method for nitration of 1,3-bis (trifluoromethyl) benzene with nitric acid, using sulfuric acid having a concentration of 91% or more or fuming sulfuric acid having a sulfur trioxide concentration of 20% or less as a solvent. The present invention relates to a process for producing 3,5-bis (trifluoromethyl) nitrobenzene, characterized by reacting in a temperature range of 50 to 100 ° C.
[0008]
Hereinafter, the present invention will be described in detail.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
The raw material 1,3-bis (trifluoromethyl) benzene can be used as it is with a normally available purity.
The first feature of the present invention is the selection of a solvent. In order to promote this reaction, a strongly acidic solvent is essential. At the same time, it is preferable that the water content is low in order to suppress side reactions such as hydrolysis. Therefore, fuming sulfuric acid containing sulfur trioxide that converts water by-produced by nitration with nitric acid into sulfuric acid of strong acid can be mentioned as a suitable solvent.
[0010]
However, as a result of detailed examination of the concentration of sulfur trioxide, the present inventor has found that by-products of sulfonated products increase at high concentrations. Accordingly, it has been found that the preferred concentration of sulfur trioxide in the fuming sulfuric acid is 20% or less, more preferably 10% or less provides a high BTFNB yield.
Furthermore, it has been newly found that BTFNB can be obtained at a sufficiently high yield even when only concentrated sulfuric acid containing no free sulfur trioxide is used as a solvent.
[0011]
The sulfuric acid concentration is preferably 91% or more and 100% or less, and it is possible to use commercially available 97% concentrated sulfuric acid which is easy to handle. When the concentration is less than 91%, the reaction is rapidly slowed down.
The amount used is preferably 1 to 20 times by weight, particularly 2 to 10 times by weight, relative to the raw material BTFB. Since the solubility of the raw material BTFB in these solvents is small, the reaction is promoted when the amount of the solvent is large.
[0012]
On the other hand, nitric acid as a nitrating agent is preferably as low in water content as possible for the reasons described above. However, in the case of a water-containing product, it can be similarly used if the amount of sulfur trioxide or fuming sulfuric acid is increased. Generally available 94% or 98% fuming nitric acid can be used as is. The amount of nitric acid must be equal to or greater than that of the raw material in order to increase the conversion rate because the raw material BTFB has low reactivity.
[0013]
If the amount of nitric acid is large, the reaction becomes faster, but it is preferable to carry out within 5 times equivalent, preferably within 4 times equivalent to the raw material BTFB because of the complicated recovery of excess nitric acid after the reaction. In the present invention, it has been found that a high BTFNB yield can be obtained even when the amount of nitric acid is about 1.5 to 2 times equivalent by examining the order of charging each reaction material and the optimum reaction temperature. (Reference example: 6.7 times)
The second feature of the present invention is the optimum reaction temperature. When nitration is performed using fuming sulfuric acid or concentrated sulfuric acid as a solvent, sulfonation occurs at a high temperature depending on the substrate. In BTFB, a sulfonated product is produced as a by-product from around 90 ° C.
[0014]
Therefore, when a high concentration fuming sulfuric acid is used as a solvent, it is necessary to react in a low temperature region. As a result of detailed examination of the temperature range of the target product BTFNB reaction yield of 80% or more with fuming sulfuric acid and concentrated sulfuric acid solvent, it was found that the temperature is preferably 50 to 100 ° C., particularly 60 to 95 ° C.
A third feature of the present invention is a method for charging each reaction material. It is preferable to control the temperature by separating the exotherm generated by the mixed acid synthesis and the exotherm generated by the nitration reaction from the viewpoint of the operability of reaction control and the selectivity of the target product.
[0015]
Since BTFB is not a concern for dinitration after mononitration, a method in which BTFB is dropped or dividedly added over time while reacting in a previously synthesized mixed acid is preferable. By this method, it is sufficient to remove heat only by the exothermic reaction of the nitration reaction or to maintain the temperature, and the reaction temperature can be easily controlled.
The dropping time or the number of divisions of BTFB varies depending on the reaction scale and the reaction apparatus. In this reaction, an organic solvent can be used in addition to the above-mentioned inorganic strong acidic solvent. Solvents that can be used include halogenated aliphatic hydrocarbons such as 1,2-dichloroethane and 1,1,2,2-tetrachloroethane, and aliphatics such as n-hexane and n-heptane. And hydrocarbons.
[0016]
The amount used is preferably 0.5 to 20 times by weight, particularly 1 to 10 times by weight, relative to the raw material BTFB.
Since this reaction is a two-layer reaction, various alkylsulfosuccinates represented by sodium di (2-ethylhexyl) sulfosuccinate, polyoxyethylene alkylallyl ethers represented by polyoxyethylene nonylphenyl ether, etc. The reaction can also be promoted by using a phase transfer catalyst such as an agent, tetrabutylammonium chloride and tetramethylammonium hydrogen sulfate.
[0017]
The amount used is suitably 0.1 to 10 mol% with respect to the raw material BTFB.
The reaction time varies depending on the reaction conditions and can be determined by analyzing the reaction solution by gas chromatography or liquid chromatography.
After the reaction, the product is separated as an oil layer when cooled to room temperature. This can be separated as it is. It can also be extracted with an organic solvent. When these are washed with water, washed with an alkaline aqueous solution, and washed again with water, by-products such as sulfonated products and decomposed products are removed.
[0018]
Further, by distilling this crude product, a target BTFB high-purity product can be obtained.
Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited thereto.
[0019]
【Example】
Example 1
160 g of 97% sulfuric acid was charged into a four-neck reaction flask, and 20.1 g of 94% fuming nitric acid was added dropwise over 1 hour with stirring under ice cooling. Subsequently, after raising the temperature of the reactor to 85 ° C., 32.1 g (0.15 ml) of 1,3-bis (trifluoromethyl) benzene (BTFB) was added dropwise over 2 hours with stirring. Thereafter, stirring was continued for 3 hours at the same temperature to stop the reaction and to cool.
[0020]
Subsequently, the product was extracted with 2 times 32 g of 1,2-dichloroethane (EDC).
This organic layer was washed with water, washed with a 10% aqueous sodium hydroxide solution and further washed with water, and then concentrated and distilled. As a main fraction, 31.1 g of an oily substance having a boiling point of 71 to 72 ° C./933 Pa was obtained.
This fraction was analyzed by gas chromatography and found to be 99% pure. Further, from MASS, 1 H-NMR and 13 C-NMR, it was found to be the desired 3,5-bis (trifluoromethyl) nitrobenzene (BTNFNB).
[0021]
As a result of quantitative determination of the EDC solution, the BTFNB reaction yield was 85.1%.
[0022]
Examples 2-7, Comparative Examples 1-5
The reaction was carried out in the same manner as in Example 1 except that the solvent, temperature and time were changed. After the reaction was completed, the results of quantification of the organic layer extracted by EDC are shown in the following table.
[0023]
[Table 1]
Comparative Example 5
In Example 1, 32.1 g of BTFB was charged all at once and the reaction was started. After about 10 minutes, an exotherm was observed and the reaction temperature rose to 93 ° C. or higher. Therefore, the oil bath was removed and cooled in a water bath.
When the temperature returned to 85 ° C., the water bath was removed and stirring was continued under air cooling. After the heat generation continued for a while, when it became 85 ° C. or lower, it was put again in an oil bath and maintained at 85 ° C. The reaction was terminated by stirring for a total of 4 hours. The reaction solution was cooled, extracted with EDC, and quantified. As a result, the BTFNB yield was 66.2%.
[0025]
【The invention's effect】
As shown in the table, according to the method of the present invention, the yield of 3,5-bis (trifluoromethyl) nitrobenzene (BTFNB) is high.
Claims (2)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP18696095A JP4022929B2 (en) | 1995-07-24 | 1995-07-24 | Method for producing 3,5-bis (trifluoromethyl) nitrobenzene |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP18696095A JP4022929B2 (en) | 1995-07-24 | 1995-07-24 | Method for producing 3,5-bis (trifluoromethyl) nitrobenzene |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0931030A JPH0931030A (en) | 1997-02-04 |
| JP4022929B2 true JP4022929B2 (en) | 2007-12-19 |
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| Application Number | Title | Priority Date | Filing Date |
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| JP18696095A Expired - Fee Related JP4022929B2 (en) | 1995-07-24 | 1995-07-24 | Method for producing 3,5-bis (trifluoromethyl) nitrobenzene |
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| JP (1) | JP4022929B2 (en) |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| DK1468983T3 (en) * | 2002-01-25 | 2008-01-07 | Asahi Glass Co Ltd | Process for the preparation of 2,5-bis (trifluoromethyl) nitrobenzene |
| US7786325B2 (en) | 2006-02-10 | 2010-08-31 | Mitsui Chemicals, Inc. | Process for producing O-methyl-N-nitroisourea |
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