WO2012140277A2 - Procédé de préparation de composés aromatiques au mononitrate - Google Patents

Procédé de préparation de composés aromatiques au mononitrate Download PDF

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WO2012140277A2
WO2012140277A2 PCT/EP2012/067356 EP2012067356W WO2012140277A2 WO 2012140277 A2 WO2012140277 A2 WO 2012140277A2 EP 2012067356 W EP2012067356 W EP 2012067356W WO 2012140277 A2 WO2012140277 A2 WO 2012140277A2
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phase
nitric acid
reaction
aqueous nitric
distillation
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WO2012140277A3 (fr
Inventor
Stefan Schlenk
Peter Wasserscheid
Christiaan RIJKSEN
Christian Noti
Paul Hanselmann
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Lonza AG
Friedrich Alexander Universitaet Erlangen Nuernberg
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Lonza AG
Friedrich Alexander Universitaet Erlangen Nuernberg
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Priority to PCT/EP2012/069305 priority Critical patent/WO2012156540A2/fr
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Publication of WO2012140277A3 publication Critical patent/WO2012140277A3/fr
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    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C201/00—Preparation of esters of nitric or nitrous acid or of compounds containing nitro or nitroso groups bound to a carbon skeleton
    • C07C201/06—Preparation of nitro compounds
    • C07C201/08—Preparation of nitro compounds by substitution of hydrogen atoms by nitro groups
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C201/00—Preparation of esters of nitric or nitrous acid or of compounds containing nitro or nitroso groups bound to a carbon skeleton
    • C07C201/06—Preparation of nitro compounds
    • C07C201/16—Separation; Purification; Stabilisation; Use of additives

Definitions

  • the invention discloses a method for preparation of mononitrated aromatic compounds in a liquid-liquid biphasic solvent system with aqueous nitric acid as one phase and ionic liquids (ILs) as the second phase, wherein the nitric acid is continuously exchanged during the reaction.
  • aqueous nitric acid as one phase
  • ionic liquids ILs
  • Mononitrated aromatic compounds and methods for their preparation are known. These compounds represent intermediates in a wide range of methods for preparation e.g. of aromatic amines and other aromatic compounds.
  • EP 1 324 973 B discloses a process for the nitration of an aromatic compound, wherein the aromatic compound is admixed with a nitrating agent in the presence of an ionic liquid.
  • the reaction system consists of only one phase.
  • the range of ionic liquids where the disclosed nitration reaction succeeds is limited to those where the corresponding acid form of the anion is stronger, or at least as strong as nitric acid.
  • Prominent examples given are the hydrogen sulfate anion and trifluoromethane sulfonate anion.
  • As cations of the ILs imidazolium cations are disclosed.
  • the nitrotoluene/residual nitric acid is distilled off at 140°C at 1 mbar.
  • the preferred distillation method is steam distillation, optionally by the addition of water before the steam distillation.
  • the ionic liquid mentioned contains a cationic, imidazolium moiety, which is prone to nitration, thereby undesired byproducts can be formed, which results in reduced long term stability of the IL.
  • DE 2 622 313 A discloses a method for the preparation of mononitrated aromatic compounds by nitration of aromatic compounds with nitric acid without the use of sulfuric acid, wherein the nitration is done in 40% to 68% (w/w) nitric acid, the reaction mixture is separated mechanically into an inorganic and an organic phase.
  • the inorganic phase is separated by rectification into one phase with lower nitric acid concentration and another phase with higher nitric acid concentration.
  • the inorganic phase and the organic phase in this method show high solubility among each other, which can be as high as 45%. Therefore cooling and/or dilution before the phase separation are/is required as well as elaborate rectification with several steps after phase separation. This is energetically and ecologically unfavorable and leads to prolonged process times.
  • the DE 2 622 313 A suggests increasing the temperature near the end of the reaction in order to shorten reaction times and to obtain higher conversion rates, but hints at the problem of dinitration.
  • the problematic and undesired possibility of dinitration which represent toxicologically problematic substances, which can even pose a security risk, necessitates in the disclosed method specific technical provisions, such as higher number of steps, such as purification and/or distillation steps, a specific flow profile and other measures.
  • Explicit recommendation is even to stop the reaction already when the turnover rate has exceeded 90% in order to avoid by products such as deriving from dinitration.
  • alkyl means linear or branched alkyl
  • halogen means F, CI, Br or I, preferably F, CI or Br;
  • Subject of the invention is a method for the preparation of a mononitrated aromatic compound by a reaction of an aromatic compound with nitric acid,
  • reaction is done in a liquid liquid biphasic system with a phase (A) and a phase (B);
  • phase (A) is an ionic liquid (A)
  • ionic liquid (A) is selected from the group consisting of nitrate, hydrogen sulfate and
  • R3 is C4-14 alkyl
  • R4 is C4-14 alkyl or C4-14 alkyl substituted by SO3H;
  • phase (B) is aqueous nitric acid (B)
  • aqueous nitric acid (B) has a concentration (CONC) at the beginning of the reaction, concentration (CONC) is from 50% to 70% of nitric acid, the % being weight percent and are based on the total weight of the aqueous nitric acid (B);
  • the average residence time of aqueous nitric acid (B) in phase (B) is smaller than the reaction time by exchange of aqueous nitric acid (B) by an aqueous nitric acid (C) during the reaction;
  • the aqueous nitric acid (C) has a concentration (C) from concentration (CONC) to 100%, the %> being weight percent and are based on the total weight of the aqueous nitric acid (C);
  • the aromatic compound is selected from the group consisting of benzene, naphthalene,
  • aromatic compound is unsubstituted or substituted with 1, 2, 3 or 4 substituents;
  • the average residence time can also be called average staying time or average dwell time, and specifies the average time how long a specific part of phase (B), that is a specific part of aqueous nitric acid (B), stays in the reaction before it is exchanged during the reaction by aqueous nitric acid (C).
  • An exchange can be done once or more than once during the reaction.
  • An exchange can be done continuously.
  • the amount of phase (B), i.e. of aqueous nitric acid (B), which is exchanged, can be a part of the amount of phase (B), it can be the total amount of the amount of phase (B), or phase (B) can be exchanged more than once during the reaction.
  • exchange of phase (B), i.e. of aqueous nitric acid (B) is done during the reaction 1 , 2, 3, 4, 5, 6, 7, 8, 9, 10, 1 1 , 12, 13, 14, 15, 16, 17, 18, 19, 20 times or continuously.
  • phase (B) i.e. aqueous nitric acid (B)
  • phase (B) is exchanged during the reaction 1 , 2, 3, 4, 5, 6, 7, 8, 9, 10, 1 1 , 12, 13, 14, 15, 16, 17, 18, 19, 20 times or continuously, and, in case of non-continuous exchange, any batchwise exchange exchanges 90 to 100% of phase (B), the % are weight % and are based on the total amount of phase (B).
  • Continuous exchange is preferred over batchwise exchange.
  • nitric acid is spent by the nitration reaction and water is produced as a side product, therefore the concentration of nitric acid in phase (B) would continuously drop during the reaction, if no phase (B) was exchanged.
  • Exchange of phase (B) serves the purpose to remove the side product water from the reaction mixture.
  • the concentration of nitric acid in phase (B) is kept either equal to or at least as near as possible to concentration (CONC).
  • CONC concentration of nitric acid in phase
  • the concentration of nitric acid in phase (B) can even be kept constant.
  • the reaction rate does no longer drop as much as it would drop without exchange, and often, in case of no exchange, the reaction even stops altogether before full conversion of the substrate.
  • the concentration of aqueous nitric acid (C) is above concentration (CONC) and the amount of exchanged phase (B) is adapted to serve the purpose of increase of the concentration of nitric acid in phase (B) over concentration (CONC).
  • this i.e. the increase of the concentration of nitric acid in phase (B) during the reaction, is usually not a preferred embodiment, since one can as well start right from the beginning with the desired higher concentration (CONC).
  • the amount of phase (B) is kept constant during the reaction by said exchange of part of phase (B) with the aqueous nitric acid (C).
  • ionic liquid (A) is selected from the group consisting of [N(R1)(R2)(R3)R4] + N0 3 " , [P(R1)(R2)(R3)R4] + N0 3 " , [N(R1)(R2)(R3)R4] + HS0 4 ⁇ , [P(R1)(R2)(R3)R4] +
  • ionic liquid (A) is selected from the group consisting of
  • ionic liquid (A) is selected from the group consisting of
  • the ionic liquid (A) is [N(R1)(R2)(R3)R4] + N0 3 " or [P(R1)(R2)(R3)R4] + N0 3 " , it can be generated from the corresponding hydrogen carbonate or carbonate.
  • the corresponding hydrogen carbonate or carbonate is converted to the nitrate when coming into contact with the nitric acid in phase (B), therefore preferably said conversion is done in situ.
  • Rl, R2, R3 and R4 are linear alkyl residues
  • R3 and R4 are identical, and Rl and R2 are identical;
  • Rl, R2, R3 and R4 are linear alkyl residues, R3 and R4 are identical and Rl and R2 are identical.
  • R3 and R4 are identical and are linear C 4 _i 2 alkyl
  • Rl and R2 are identical and are linear C 1-12 alkyl.
  • the ionic liquid (A) is selected from the group consisting of [N(n- butyl) 4 ] + N0 3 " , [P(n-butyl) 4 ] + N0 3 " , [N(n-hexyl) 4 ] + N0 3 " , [P(n-hexyl) 4 ] + N0 3 " , [N(n- octyl) 4 ] + N0 3 " , [P(n-octyl) 4 ] + N0 3 " , [N(n-dodecyl) 4 ] + N0 3 " , [P(n-dodecyl) 4 ] + N0 3 " , [N(CH 3 )(n-octyl) 3 ] + N0 3 " , [P(CH 3 )(n-octyl) 3 ] + N0 3 " , [P(CH 3 )(n-octyl) 3 ] + N
  • concentration (CONC) is from 60% to 70%, more preferably from 61% to 69%, even more preferably from 61 > to 68%>, especially 65%>, of nitric acid, the %> being weight percent and are based on the total weight of the aqueous nitric acid (B).
  • concentration (C) is from concentration (CONC) to 70%, the % being weight percent and are based on the total weight of the aqueous nitric acid (C).
  • the molar amount of nitric acid (B) in phase (B) is 1 to 10 fold, more preferably 1 to 6 fold, of the molar amount of aromatic compound.
  • the aromatic compound is selected from the group consisting of benzene,
  • aromatic compound is unsubstituted or with 1 , 2, 3 or 4 substituents substituted;
  • substituents are identical or different and independently from each other selected from the group consisting of Ci_io alkyl, C5-6 cycloalkyl, and halogen;
  • the aromatic compound is selected from the group consisting of toluene, xylene, chlorobenzene, naphthalene, biphenyl and diphenyl ether;
  • the aromatic compound is selected from the group consisting of
  • the aromatic compound is selected from the group consisting of toluene, m-xylene, chlorobenzene, naphthalene and diphenyl ether;
  • the aromatic compound is selected from the group consisting of toluene, m- xylene and chlorobenzene.
  • the molar amount of ionic liquid (A) is 0.01 to 100 fold, more preferably 0.05 to 50 fold, even more preferably 0.1 to 10 fold, especially 0.2 to 2 fold, of the molar amount of aromatic compound (A).
  • the reaction can be done under pressure, such as from atmospheric pressure to 400 bar.
  • the reaction is done at a temperature (A) of -25 °C to 250 °C, more preferably of 0 °C to 200 °C, even more preferably 20 °C to 200 °C, especially of 25 °C to 180 °C.
  • the reaction time of the reaction is from 1 min to 72 h, more preferably from 15 min to 12 h, even more preferably from 30 min to 3h, especially from 30 min to 90 min.
  • reaction can be done under inert atmosphere.
  • an inert atmosphere is made from a gas (A) selected from the group consisting of nitrogen, helium, neon, argon, carbon dioxide and mixtures thereof.
  • gas (A) is nitrogen or carbon dioxide.
  • the exchange of part of phase (B) with the aqueous nitric acid (C) during the reaction is done by removal of a part of phase (B) during the reaction and addition of the aqueous nitric acid (C).
  • N0 2 and the oxidizing agent are added preferably in a molar ratio of 2 mol equivalents N0 2 to 0.5 mol equivalents oxidizing agent.
  • the amount of N0 2 and oxidizing agent, which is contacted with the removed part of phase (B), is such that concentration (C) is attained in the removed part of phase (B) by this regeneration.
  • concentration (C) is attained in the removed part of phase (B) by this regeneration.
  • the removed part of phase (B) after regeneration is used as aqueous nitric acid (C), which is added to the reaction mixture during the reaction in exchange for the removed part of phase (B).
  • the removed part of phase (B) is regenerated by distillation.
  • the removed part of phase (B) is regenerated by a combination of contacting with N0 2 and an oxidizing agent as described above, also in all its described embodiments, and distillation.
  • the regeneration is done first by contacting with N0 2 and the oxidizing agent, until a concentration of nitric acid of 60 to 64 % is attained, and then the distillation is done to attain a concentration of nitric acid of 65%, which represents preferably concentration (CONC) and concentration (C).
  • phase (A) is distilled after the reaction, in this distillation the mononitrated aromatic compound is distilled off; a distillation residue remains, this distillation residue contains the ionic liquid.
  • an entrainer is present in the distillation, the entrainer is water or aqueous nitric acid.
  • the entrainer is water or part of phase (B), with phase (B) as defined above, also with all its preferred embodiments.
  • the distillation can be done under reduced pressure.
  • an entrainer is present, the entrainer and the mononitrated aromatic compound form after the distillation two phases and can therefore easily be separated; preferably, the entrainer and the mononitrated aromatic compound are separated after the distillation.
  • the amount of entrainer can vary.
  • the amount of entrainer is 0.001 to 10 fold, more preferably 0.01 to 5 fold, of the weight of phase (A).
  • the entrainer can be recycled during distillation.
  • the ionic liquid (A) does not distill and therefore represents the distillation residue or distillation sump. After distillation, the said distillation residue can be added to the reaction mixture as phase (A).
  • the distillation residue is used for phase (A), with phase (A) as defined above, also with all its preferred embodiments; preferably without further treatment.
  • the entrainer which was separated from the mononitrated compound after the distillation, is used for phase (B), with phase (B) as defined above, also with all its preferred embodiments.
  • the entrainer can e.g. be added to the removed part of phase (B), or to the reaction mixture.
  • the entrainer removed during the distillation is used to attain the concentration (C) and/or to adjust the amount of the aqueous nitric acid (C) in the removed part of phase (B) for regeneration.
  • the concentration (C) is attained in the removed part of phase (B) by the amount of N0 2 and oxidizing agent.
  • the main reaction stoichiometries are: a) aromatic compound + ITNO 3 -> mononitrated aromatic compound + H 2 0 b) H 2 0 + 2 NO2 -> HNO3 + HNO2
  • the concentration of nitric acid in phase (B) can be kept constant during the reaction, preferably the concentration of nitric acid in phase (B) and the amount of phase (B) are kept constant simultaneously.
  • part of phase (B) When part of phase (B) is used as entrainer, the method in total produces a minimal amount of nitric acid as a waste stream.
  • phase (A) When the entrainer is water and is added before the distillation of phase (A), the method in total can consume water and produces nitric acid as a waste stream
  • an entrainer is present in the distillation and the entrainer is aqueous nitric acid; preferably the entrainer is part of phase (B).
  • said method comprising said distillation, wherein the water, which is extracted from the reaction mixture by the distillation, and which is extracted after the distillation, preferably in form of an aqueous nitric acid, and the N0 2 and the oxidizing agent, which are used for the regeneration of the part of phase (B) after its removal from the reaction mixture, are used to keep the concentration of nitric acid in phase (B) constant during the reaction;
  • phase (B) preferably to keep the concentration of nitric acid in phase (B) and the amount of phase (B) constant during the reaction;
  • distillation is preferably done with an entrainer, with the entrainer as described above, also with all its preferred embodiments.
  • the method or the reaction can be done batch wise or continuously. Continuously means, that the reaction is done in a continuous way in a reactor for continuous reactions, called continuous reactor in the following.
  • continuous reactor in the following.
  • a continuous reaction apparatus has two domains: a reactor R, where the two phases are mixed, and a separator S, where the two phases are allowed to separate.
  • the aromatic compound and the ionic liquid as a stream R(in A), and the aqueous nitric acid as a stream R(in B) are continuously fed into reactor R; from separator S part of the two phases S(out A) and S(out B) are continuously discharged, S(out A) contains ionic liquid, unreacted aromatic compound and mononitrated aromatic compound.
  • S(out B) contains water and nitric acid and is regenerated with N0 2 and oxidizing agent for use as R(in B).
  • the content of R is being fed into S continuously.
  • the streams are adjusted in such a way, that a steady state condition is realized.
  • the distillation residue or distillation sump is used for R(in A), the optional entrainer for R(in B).
  • phase S p (out B) preferably after having combined them, N0 2 and oxidizing agent is passed for regeneration of the concentration of the nitric acid, then the thus regenerated aqueous nitric acid is used for R(in B).
  • Part of the thus regenerated aqueous nitric acid can be purified in counter current extraction with the aromatic compound, said aromatic compound is then used for feeding into R 1 .
  • the two phases are distilled.
  • a distillation column can be chosen, which provides no or provides a separation of the residual aromatic compound from the mononitro aromatic compound.
  • the aqueous nitric acid from this distillation is treated in the same way as the phases S p (out B).
  • the sump of the distillation can be used for feeding R 1 .
  • the process parameters can be adjusted in such a way, that a high conversion of aromatic compound into mononitrated aromatic compound is attained, but the amount of byproducts is kept low.
  • a continuous method can be done in such a way, that only a low, preferably from 10% to 40%, conversion rate of aromatic compound into mononitrated aromatic compound is attained, the conversion rate in % are mol % of mononitrated aromatic compound based on the total molar amount of aromatic compound used for the reaction.
  • the crude product mixture comprising
  • mononitrated aromatic compound, aromatic compound, phase (A) and phase (B) can be fed again into the continuous reactor and be subjected again to the conditions of the reaction.
  • Such a technique would be suitable for a continuous loop reactor set-up.
  • a loop reactor functions in principle in the same way as a continuous reactor set up, except for the fact, that R and S are separated by time rather than by space, i.e. the reaction mixture is fed from the separator S back into the reactor R.
  • a continuous method or continuous reaction has the advantage, that residence time of the product at the elevated temperature can be minimized, thereby side reactions can be further avoided or at least further minimized.
  • the method of the present invention uses inexpensive starting materials such as aqueous nitric acid, N0 2 and as oxidizing agent air or 0 2 . No toxicologically problematic waste streams are generated, actually the only waste generated is the water, that is generated due to the overall stoichiometry of the whole reaction system, and which is therefore inherently unavoidable, and which is the only side product which needs to be discarded off. This water is obtained from the distillation in form of aqueous nitric acid and recycled into the regeneration of the removed part of phase (B), and therefore can be discharged from the reaction system e.g.
  • aqueous nitric acid of concentration (C) which represents actually not a waste, but a substance useful in chemical reactions.
  • This discharged aqueous nitric acid can further be purified from residual ionic liquid and from product, i.e. mononitrated aromatic compound, by extraction with the substrate, i.e. with the aromatic compound.
  • the anion of the ionic liquid is preferably N0 3 , therefore derived from nitric acid, which is the nitrating agent, and therefore no additional anion is introduced into the system in the preferred embodiment, thereby inherently reducing the amount of possible side reactions. Due to the use N0 2 and 0 2 for the regeneration of the nitric acid, also from this process step no waste stream results.
  • phase (A) is not prone to nitration, thereby no undesired by products can be formed, the long term stability is provided. Since phase (A) and phase (B) show low solubilities among each other, good phase separation is observed, no cooling or dilution before the phase separation is mandatorily required.
  • the distillation is simple, does not require multiple column plates, and the process is energetically and ecologically favorable with short overall process times. Furthermore the low cross solubilities of phase (A), phase (B) and the product, i.e. the mononitrated aromatic compound, provide a high recovery rate of the product, only up to 10% of product was observed to be discharged via phase (B).
  • phase (B) Due to the regeneration of phase (B) and its recycling back into the process, the thus discharged product is not lost, does not require a separate isolation or complex rectification, but is simply fed back into the process. No sulfuric acid is used for the nitration reaction, therefore no sulfate containing waste is generated; in case that the anion of the ionic liquid (A) is not nitrate, the respective amount of said anion different from nitrate is still considerably lower than the amount of sulfate when sulfuric acid would be used in the nitration reaction.
  • the method provides for constant reaction parameters such as concentration of nitric acid, which can be selected to fit optimal for the targeted reaction and substrate, thereby dinitration and other side reactions are effectively controlled and reduced, without requiring special technical provisions, and thereby also high conversion rates do not increase side reactions. This results in improved selectivity of the method. Actually only mono nitration and no dinitration was observed in any of the inventive examples described below.
  • the method of the present invention can be performed continuously, which provides a more constant product quality than batch wise processes.
  • a continuous method is also more convenient for the large scale production of compounds, because fewer operations and fewer operators are required, because no dangerous accumulation of starting materials occurs, and because the process is easier to control.
  • the method of the present invention can be conducted batch wise.
  • the ionic liquids were purchased, since they are commercially available, if not otherwise stated.
  • the conversion in the examples is a molar conversion rate and is given in %, the % being based on the total molar amount of aromatic compound used for the reaction; of not stated otherwise.
  • the conversion rate and the ratio of isomers were detected by gas chromatography, if not stated otherwise.
  • the ratio of isomers is given in form of the ratio of the areas of the peaks of the isomers in the GC chromatogram, with the biggest area normalized to 100%.
  • 100% conversion means, that no substrate was detectable by GC.
  • the reaction mixture was cooled to room temperature.
  • the organic phase which was the upper phase and which represents phase (A) was extracted with dibutyl ether (once with 20 ml) to provide a mixture of nitrotoluene isomers and dibutyl ether, the conversion was 100 % and the ratio between 2-, 3- and 4-isomer was 1 : 0.07 : 0.67.
  • the reaction mixture was cooled to room temperature. After phase separation, the organic phase, which was the upper phase, was extracted with dibutyl ether (once with 20 ml) to provide a mixture of nitrotoluene isomers and dibutyl ether, the conversion was 100 % and the ratio between 2-, 3- and 4-isomer was 1 : 0.06 : 0.56.
  • the reaction mixture was cooled to room temperature. After phase separation, the organic phase, which was the upper phase, was extracted with dibutyl ether (once with 20 ml) to provide a mixture of nitrotoluene isomers and dibutyl ether, the conversion was 100 % and the ratio between 2-, 3- and 4-isomer was 1 : 0.07 : 0.56.
  • reaction mixture was a liquid-liquid biphasic mixture as it was in example 2.
  • N-decyl-N,N-dimethyldecan-l -ammonium carbonate/hydrogen carbonate 10.0 g
  • 65 % (w/w) aqueous HN0 3 was added until pH was between 6.0 and 7.0.
  • a biphasic system was obtained.
  • the organic phase was washed with distilled (once with 20 ml) water to yield N-decyl-N,N-dimethyldecan-l -ammonium nitrate.
  • Tri-n-butyl amine (10.0 g, 54.0 mmol) and 1,4-butane sultone (5.5 mL, 100 mol-%) were mixed. The mixture was heated to 160 °C, refluxed at 160 °C for 3 days and cooled to room temperature. 65 % (w/w) aqueous HN0 3 (5.2 g, 100 mol-%) was added. Extraction with dichloromethane (once with 20 ml) and evaporation of dichloromethane yields ⁇ , ⁇ , ⁇ - tributyl-4-sulfobutane- 1 -ammonium nitrate.
  • Tetra-n-butyl ammonium bromide (10.0 g, 31.0 mmol) was dissolved in 100 ml water, and lithium trifluoromethane sulfonate (5.3 g, 110 mol-%) was dissolved in 20 ml water. Both solutions were mixed at room temperature, stirred for 30 min at room temperature and extracted with dichloromethane (once with 20 ml) to yield tetra-n-butyl ammonium
  • Tri-n-octyl amine (10.0 g, 28.3 mmol) was dissolved in dichloromethane and cooled to 0 °C.
  • Methyl trifluoromethane sulfonate (5.6 g, 120 mol-%) was added dropwise at 0 °C. The mixture was then heated to 50 °C and refluxed at 50 °C for 24 h. Evaporation of
  • Tri-n-octyl amine (19.1 g, 54.0 mmol) and 1,4-butane sultone (5.5 mL, 100 mol-%) were mixed. The mixture was heated to 170 °C, refluxed at 170 °C for 5 days and cooled to room temperature. 65 % (w/w) aqueous HN0 3 (5.2 g, 100 mol-%) was added. Extraction with dichloromethane (once with 20 ml) and evaporation of dichloromethane yields N,N-dioctyl- N-(4-sulfobutyl)octan- 1 -ammonium nitrate .
  • the reaction mixture was cooled to room temperature. After phase separation, the organic phase, which was the upper phase, was extracted with dibutyl ether (once with 20 ml), to provide a mixture of nitrotoluene isomers and dibutyl ether, the conversion was 100 % and the ratio between 2-, 3- and 4-isomer was 1 : 0.09 : 0.65.
  • spent aqueous phase B was a collection of exchanged aqueous nitric acid phase from repetitions of example 2, which was the so called lower phase as described in example 2.
  • small amounts of water were used to wash the spent aqueous phases B from the apparatus, which caused the concentration of nitric acid in the such collected spent aqueous phase B at the beginning to be lowered to 48.4 % by weight of nitric acid.
  • Nitric acid concentration is measured by titration and reached 65 % by weight of nitric acid after a total time of 90 min.
  • Example 2 was repeated with the following differences:
  • the regenerated aqueous nitric acid (33.4 g, 300 mol-%) produced according to example 7 was used for exchange of the aqueous phase, and not fresh aqueous nitric acid as was used example 2.
  • the reaction mixture is a liquid-liquid biphasic mixture as in example 2.
  • Phase (A) was prepared according to example 2, where, after the reaction mixture was cooled to room temperature and before any extraction with dibutyl ether, the two phases of the reaction mixture were separated.
  • the upper phase was phase (A).
  • phase (A) 40 mL water were added.
  • the mixture was distilled at 130 °C and ambient pressure using a Dean- Stark-apparatus, which allowed recycling of the water during the distillation, which acted as entrainer.
  • the distillation in a Dean-Stark-apparatus represents a distillation with only one column plate.
  • the sump (i.e. the distillation residue) contained 50.3 % ionic liquid, 42.2 % nitric acid and 7.5 % water, the % being weight percent and are based on the total weight of the sump.
  • the distillate was biphasic.
  • the lower phase was the organic phase, 99.2 % of the organic phase was a mixture of nitrotoluene isomers.
  • the upper phase was the aqueous phase and contained 11.0 % (w/w) aqueous nitric acid, both % values are weight percent and are based on the total weight of the respective phase.
  • Chlorobenzene (13.3 g, 118.3 mmol), 65 % (w/w) aqueous nitric acid (36.2 g, 316 mol-% based on substrate) and [N(n-butyl) 4 ] + OTf (13.9 g, 30 mol-% based on substrate) were mixed. A liquid- liquid biphasic mixture was obtained. The mixture was heated to 110 °C and stirred at 110 °C for a total reaction time of 120 min.
  • the reaction mixture was cooled to room temperature. After phase separation, the organic phase, which was the upper phase, was extracted with dibutyl ether (once with 20 ml), to provide a mixture of chlorobenzene, chloro nitrobenzene isomers and dibutyl ether, the conversion was 97.9 % and the ratio between l-chloro-2-nitrobenzene : l-chloro-3- nitrobenzene : l-chloro-4-nitrobenzene was 1 : 0.02 : 2.53.
  • the reaction mixture was cooled to room temperature. After phase separation, the organic phase, which was the upper phase, was extracted with dibutyl ether (once with 20 ml), to provide a mixture of nitro xylene isomers and dibutyl ether, the conversion was 100 % and the ratio between 2-nitro-m-xylene : 4-nitro-m-xylene : 5-nitro-m-xylene was 1 : 6.41 : 0.07 This mixture contains 2% of unidentified byproducts.
  • Naphthalene (14.5 g, 113.4 mmol), 65 % (w/w) aqueous nitric acid (33.4 g, 300 mol-%> based on substrate) and [N(n-butyl) 4 ] + N0 3 (10.2 g, 30 mol-%> based on substrate) were mixed.
  • a liquid-liquid biphasic mixture was obtained. The mixture was heated to 110 °C and stirred at 110 °C for a total reaction time of 60 min.
  • the reaction mixture was cooled to room temperature. After phase separation, a sample of the organic phase, which was the upper phase, was extracted with dibutyl ether (once with 2 ml), to provide a mixture of nitro naphthalene isomers and dibutyl ether, the conversion was 100 % and the ratio between 1-nitro-naphthalene : 2-nitro-naphthalene was 1 : 0.02. This mixture contains 4.7% 1,5-dinitro-naphthalene. Entrainer distillation of the organic phase according to example 11 at 140 °C gave a mixture of nitro naphthalene isomers in the lower phase of the distillate.
  • Biphenyl (17.5 g, 113.4 mmol), 65 % (w/w) aqueous nitric acid (33.4 g, 300 mol-% based on substrate) and [N(n-butyl) 4 ] + N0 3 (10.2 g, 30 mol-% based on substrate) were mixed. A liquid-liquid biphasic mixture was obtained. The mixture was heated to 110 °C and stirred at 110 °C for a total reaction time of 60 min.
  • the reaction mixture was cooled to room temperature. After phase separation, a sample of the organic phase, which was the upper phase, was extracted with dibutyl ether (once with 2 ml), to provide a mixture of nitro biphenyl isomers and dibutyl ether, the conversion was 100 % and the ratio between 2-nitro-biphenyl : 4-nitro-biphenyl was 1 : 1.19. This mixture contains 6.6% dinitro-biphenyl.
  • Diphenyl ether (19.3 g, 113.4 mmol), 65 % (w/w) aqueous nitric acid (33.4 g, 300 mol-% based on substrate) and [N(n-butyl) 4 ] + N0 3 (10.2 g, 30 mol-% based on substrate) were mixed.
  • a liquid- liquid biphasic mixture was obtained. The mixture was heated to 100 °C and stirred at 100 °C for a total reaction time of 60 min.
  • the reaction mixture was cooled to room temperature. After phase separation, a sample of the organic phase, which was the upper phase, was extracted with dibutyl ether (once with 2 ml), to provide a mixture of nitrophenyl phenyl ether isomers and dibutyl ether, the conversion was 100 % and the ratio between 2-nitrophenyl phenyl ether : 4-nitrophenyl phenyl ether was 1 : 3.3. Entrainer destination of the organic phase according to example 11 at 140 °C gave a mixture of nitro phenyl phenyl ether isomers in the lower phase of the distillate.
  • phase (A) was prepared according to example 2 and distilled according to example 9. After the distillation, the sump (i.e. the distillation residue) contained 75.4 % ionic liquid, 18.3 % nitric acid and 6.1 % water, the % being weight percent and are based on the total weight of the sump.
  • a liquid-liquid biphasic mixture was obtained.
  • the mixture was heated to 110 °C and stirred at 110 °C for a total reaction time of 60 min. After 15, 30 and 45 min of stirring, the stirring was stopped and the aqueous phase, which was the lower phase, was exchanged with 65 % (w/w) aqueous nitric acid (66.7 g, 300 mol-%), average residence time of aqueous nitric acid (B) therefore was 15 min.
  • the reaction mixture was cooled to room temperature. After phase separation, 40 mL of water were added to the organic phase, which was the upper phase.
  • the mixture was distilled at 130 °C and ambient pressure using a Dean-Stark-apparatus, which allowed recycling of the water during the distillation, which acted as entrainer.
  • the distillation in a Dean-Stark-apparatus represents a distillation with only one column plate.
  • the sump (i.e. the distillation residue) contained 68.4 % ionic liquid, 24.9 % nitric acid and 6.7 % water, the % being weight percent and are based on the total weight of the sump.
  • the distillate was biphasic.
  • the lower phase was the organic phase, which was a mixture of nitrotoluene isomers, the conversion was 100 % and the ratio between 2-, 3- and 4-isomer was 1 : 0.07 : 0.67.
  • the upper phase was the aqueous phase.
  • a liquid- liquid biphasic mixture was obtained.
  • the mixture was heated to 110 °C and stirred at 110 °C for a total reaction time of 60 min. After 15, 30 and 45 min of stirring, the stirring was stopped and the aqueous phase, which was the lower phase, was exchanged with 65 % (w/w) aqueous nitric acid (66.7 g, 300 mol-%>), average residence time of aqueous nitric acid (B) therefore was 15 min.
  • the reaction mixture was cooled to room temperature. After phase separation, to the organic phase, which was the upper phase, 40 mL of water were added.
  • the mixture was distilled at 130 °C and ambient pressure using a Dean-Stark-apparatus, which allowed recycling of the water during the distillation, which acted as entrainer.
  • the distillation in a Dean-Stark-apparatus represents a distillation with only one column plate.
  • the sump (i.e. the distillation residue) contained 69.6 % ionic liquid, 23.9 % nitric acid and 6.5 % water, the % being weight percent and are based on the total weight of the sump.
  • the distillate was biphasic.
  • the lower phase was the organic phase, which was a mixture of nitrotoluene isomers, the conversion was 100 % and the ratio between 2-, 3- and 4-isomer was 1 : 0.08 : 0.67.
  • the upper phase was the aqueous phase.
  • a liquid- liquid biphasic mixture was obtained.
  • the mixture was heated to 110 °C and stirred at 110 °C for a total reaction time of 60 min. After 15, 30 and 45 min of stirring, the stirring was stopped and the aqueous phase, which was the lower phase, was exchanged with 65 % (w/w) aqueous nitric acid (66.7 g, 300 mol-%>), average residence time of aqueous nitric acid (B) therefore was 15 min.
  • the reaction mixture was cooled to room temperature. After phase separation, to the organic phase, which was the upper phase, 40 mL of water were added.
  • the mixture was distilled at 130 °C and ambient pressure using a Dean-Stark-apparatus, which allowed recycling of the water during the distillation, which acted as entrainer.
  • the distillation in a Dean-Stark-apparatus represents a distillation with only one column plate.
  • the sump (i.e. the distillation residue) contained 62.8 % ionic liquid, 31.1 % nitric acid and 6.0 % water, the % being weight percent and are based on the total weight of the sump.
  • the distillate was biphasic.
  • the lower phase was the organic phase, which was a mixture of nitrotoluene isomers, the conversion was 100 % and the ratio between 2-, 3- and 4-isomer was 1 : 0.07 : 0.63.
  • the upper phase was the aqueous phase.
  • a liquid- liquid biphasic mixture was obtained.
  • the mixture was heated to 110 °C and stirred at 110 °C for a total reaction time of 60 min. After 15, 30 and 45 min of stirring, the stirring was stopped and the aqueous phase, which was the lower phase, was exchanged with 65 % (w/w) aqueous nitric acid (66.7 g, 300 mol-%>), average residence time of aqueous nitric acid (B) therefore was 15 min.
  • the reaction mixture was cooled to room temperature. After phase separation, to the organic phase, which was the upper phase, 40 mL of water were added.
  • the mixture was distilled at 130 °C and ambient pressure using a Dean-Stark-apparatus, which allowed recycling of the water during the distillation, which acted as entrainer.
  • the distillation in a Dean-Stark-apparatus represents a distillation with only one column plate.
  • the sump (i.e. the distillation residue) contained 65.1 % ionic liquid, 28.7 % nitric acid and 6.1 % water, the % being weight percent and are based on the total weight of the sump.
  • the distillate was biphasic.
  • the lower phase was the organic phase, which was a mixture of nitrotoluene isomers, the conversion was 100 % and the ratio between 2-, 3- and 4-isomer was 1 : 0.08 : 0.68.
  • the upper phase was the aqueous phase.
  • the reaction mixture was cooled to room temperature. After phase separation, the organic phase, which was the upper phase, was extracted with dibutyl ether (once with 20 ml) to provide a mixture of nitrotoluene isomers and dibutyl ether, the conversion was 99.0 % and the ratio between 2-, 3- and 4-isomer was 1 : 0.09 : 0.66.

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Abstract

L'invention concerne un procédé de préparation de composés aromatiques au mononitrate dans un système de solvant biphasique liquide-liquide, de l'acide nitrique aqueux constituant une phase et des liquides ioniques (IL) une seconde phase, l'acide nitrique étant soumis à un échange continu pendant la réaction.
PCT/EP2012/067356 2012-03-08 2012-09-06 Procédé de préparation de composés aromatiques au mononitrate Ceased WO2012140277A2 (fr)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103113232A (zh) * 2013-01-22 2013-05-22 南京理工大学 一种在微反应器中催化硝化甲苯的方法

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2622313A1 (de) 1976-05-19 1977-12-01 Bayer Ag Verfahren zur herstellung von mononitroaromaten
EP1324973B1 (fr) 2000-10-10 2010-03-24 The Queen's University of Belfast Reactions de nitration aromatique

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA2356564A1 (fr) * 2001-09-05 2003-03-05 Cytec Canada Inc. Nitration de composes aromatiques

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2622313A1 (de) 1976-05-19 1977-12-01 Bayer Ag Verfahren zur herstellung von mononitroaromaten
EP1324973B1 (fr) 2000-10-10 2010-03-24 The Queen's University of Belfast Reactions de nitration aromatique

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103113232A (zh) * 2013-01-22 2013-05-22 南京理工大学 一种在微反应器中催化硝化甲苯的方法

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