Classifications

• • 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
  • C07B—GENERAL METHODS OF ORGANIC CHEMISTRY; APPARATUS THEREFOR
  • C07B43/00—Formation or introduction of functional groups containing nitrogen
  • C07B43/02—Formation or introduction of functional groups containing nitrogen of nitro or nitroso groups

Definitions

• the present invention relates to a process for the preparation of aromatic nitro compounds by reacting aromatic compounds with HNO 3 and optionally nitric acids containing H2SO4 and / or H3PO 4 and / or H2O, which is carried out in the presence of surface-active substances.
• nitro compounds are important intermediates for the production of plastics, dyes, auxiliaries, pharmaceuticals and others
• the di- (2-ethylhexyl) sulfosuccinic acid Na salt is used in an amount of 0.17 g, based on the nitrating agent consisting of 4.1 g SO 3 and 4 g NO2.
• the yield of 1 - and 2-nitroanthraquinone achieved is not higher than in other examples without the use of the di- (2-ethylhexyl) sulfosuccinic acid sodium salt mentioned.
• reaction conditions include a mixed acid of 41.41% by weight H 2 SO 4 , 1% by weight HNO3 and the rest 100% by weight water. This phenomenon of slowing down the reaction leads to a drastic reduction in the space-time yield in technical implementation.
• the invention relates to a process for the preparation of aromatic nitro compounds by reacting nitrable aromatic compounds with nitrating acids, which contain HNO3 and optionally H2SO4 and or H3PO4 and / or H 2 O, at normal to elevated temperature with constant mixing of the aromatic compounds and the nitrating acids characterized in that the reaction mixture contains one or more surfactants from the group of anionic, cationic, zwitterionic or nonionic surfactants in an amount of 0.5 to 20,000 ppm.
• Surface-active substances which are suitable for the process according to the invention can belong to the group of anionic, cationic, zwitterionic or nonionic surface-active substances.
• Anionic surface-active substances are, for example, ligninsulfonic acids, formaldehyde condensation products with aromatically bound sulfonic acid groups, protein condensation products, alkanesulfonates, alkylarylsulfonates and alkyl sulfates.
• Cationic surface-active substances are, for example, the quaternary ammonium salts.
• Zwitterionic surfactants are betaines and sulfobetaines.
• Nonionic surface-active substances are polyethers which are formed by alkoxylation of compounds with a mobile H atom with ethylene oxide, propylene oxide or butylene oxide or a mixture of several of them.
• Compounds with a mobile H atom of this type are, for example, alcohols, alkylphenols, phenols, alkylamines, carboxylic acids and carboxamides.
• Such surfactants, their structure and their production are known to the person skilled in the art.
• those from the group of anionic or cationic surface-active substances are preferred, particularly preferably those from the group of anionic surface-active substances are suitable for use in the process according to the invention.
• these are alkanesulfonates or alkyl sulfates with 10 to
• One or more of the surface-active substances can be used in a mixture.
• the amount of surface-active substances in the reaction mixture is, for example, 0.5 to 20,000 ppm, preferably 1 to 2,000 ppm, particularly preferably 1 to 200 ppm, very particularly preferably 5 to, at the reactor inlet
• the surface-active substance or a mixture of several is stable and remains in the waste acid depleted in HNO3 and can be used again according to the invention in the context of the re-concentration and new use of the waste acid.
• the surface-active substance or a mixture of several is stable under the process conditions according to the invention, but migrates into the organic phase of the aromatic nitro compound and is discharged from the process according to the invention in the course of various washing and other treatment processes and accordingly has to be metered in, for example at the reactor inlet .
• the surface-active substance or a mixture of several is not completely stable under the process conditions according to the invention; however, it acts in the sense of the invention during the nitration reaction, but must be replenished to the extent that it is broken down / destroyed.
• the surface-active substances can be introduced into the reaction mixture in various ways: it is thus possible to add the surface-active substances to the feed stream of the organic compounds to be nitrated and / or to the Feed the nitric acid feed stream.
• the surface-active substances can also be added to the reaction mixture as a separate feed stream, for example at the reactor inlet.
• the nitriding process according to the invention characterized by the use of surface-active substances, can otherwise be applied to all current processes which work with nitrating acids from HNO 3 and optionally H 2 SO and / or H 3 PO and / or H 2 O.
• work can be carried out under adiabatic or isothermal conditions. Because of the possibility of energy recovery at a high level, adiabatic conditions are preferred.
• the reaction according to the invention can be carried out in a continuous or batchwise procedure. Since the aim is also to incorporate products with smaller tonnages into the more economical continuous procedure, this continuous procedure is preferred.
• the process according to the invention can be carried out in all reactors known to those skilled in the art for nitration reactions.
• Examples include: The completely back-mixed stirred tank for batch nitriding as well as in the form of a continuous stirred tank for continuous nitriding; a cascade of stirred tanks consisting of, for example, 2 to 5 stirred tanks for continuous nitration; a reaction tube as a reactor for continuous nitrations. All of the reactors mentioned, but in particular the reaction tube, can be equipped with baffle plates, perforated plates or static mixers.
• the acid phase Due to the generally larger volume fraction of the acid phase compared to the organic phase of the compound to be nitrated, the acid phase is present as a continuous phase, while the organic phase of the compound to be nitrided is dispersed in the continuous phase by stirring elements or by dispersion on perforated plates.
• the nitrating acid and the compound to be nitrided can be combined by simply feeding both substances through pipelines into the reactor, in which they are then dispersed in the manner specified. be greeded.
• the aromatic compound to be nitrated is introduced into the nitrating acid via one or more nozzles and then redispersed by the stirring described or by means of perforated plates, slots and similar devices.
• Aromatic compounds to be nitrated may be mentioned, for example: benzene, toluene, o-, m- or p-xylene, chlorobenzene, bromobenzene, chlorotoluene, bromotoluene, o-, m-, p-dichlorobenzene, phenol, naphthalene, methylnaphthalene, phenol and phenol derivatives and aromatic amines and their derivatives. Most of these substances are liquid under reaction conditions. In principle, aromatic compounds which are solid under reaction conditions are accessible to the process according to the invention; in such cases an auxiliary solvent is used to obtain a liquid phase to be nitrided. Preferred aromatic compounds which are nitrided according to the invention are benzene, toluene, chlorobenzene and o-dichlorobenzene.
• the nitrating acid used for the nitration contains HNO3 and optionally H 2 SO4 and / or H3PO 4 and / or water.
• a nitrating acid is used which contains HNO 3 and optionally H2O.
• mixed nitrating acid HNO 3 , H 2 SO and possibly H2O
• the H2SO4 is sometimes completely or partially
• nitrating acids can additionally contain one or more of the surface-active substances mentioned above.
• the nitrating acid contains HNO3, H2SO 4 and possibly a 100% by weight residue of H 2 O and optionally one or more surface-active substances.
• nitrating acids which contain 20 to 40% by weight HNO 3 , 49 to 60% by weight H 2 SO 4 and 1 1 to 20% by weight H 2 O (Ullmanns Encyklopadie der techn chemie, 4, ed., vol. 17, p. 386 (1979)).
• nitrating acids are used, which preferably have 1 to 8% by weight, preferably 2 to 6% by weight, particularly preferably 2.5 to 5% by weight of HNO 3 and 56-85% by weight 64 to 79 wt .-% H 2 SO 4 included.
• the rest, 100% by weight, is water. All percentages refer to the total weight of H2SO 4 , HNO3 and H2O.
• the reactants are mixed in a wide range from 20 to 160 ° C.
• Aromatic compounds which are more sensitive to undesired further nitriding and oxidation are mixed in a lower part of this range, for example from 20 to 110 ° C., preferably 30 to 100 ° C., particularly preferably 40 to 90 ° C., in a manner known in the art .
• Such a sensitive aromatic compound is, for example, toluene.
• Oxidation takes place in a higher part of the range mentioned, for example from 60 to 160 ° C., preferably 70 to 140 ° C., particularly preferably 80 to 120 ° C.
• Such less sensitive aromatic compounds are, for example, chlorobenzene, bromobenzene, dichlorobenzenes.
• Nitrating acid is generally 0.9 to 1.5: 1.
• the molar ratio of aromatics to HNO 3 is preferably 1.0 to 1.5: 1, particularly preferably 1.03 to 1.3: 1, very particularly preferably moves 1.05 to 1.2: 1.
• the wider range, starting with 0.9 mol of aromatic to 1 mol of HNO 3 is also permissible.
• a special variant of the nitriding process according to the invention in the presence of surface-active substances relates to the production of mononitrotoluenes.
• the special variant accordingly relates to a process for the continuous or discontinuous production of mononitrotoluenes by reacting toluene with an HN ⁇ 3 ⁇ 2S ⁇ 4 / ⁇ 2 ⁇ mixture in the presence of 0.5 to 20,000 ppm of one or more surface-active substances to form essentially the mononitrotoluenes and water of reaction, characterized by the steps
• the amount of HNO3 is 1-8% by weight, the amount of H2SO4 is 56 to 85, preferably 58 to 74% by weight and the amount of H2O is 100% by weight and 100% by weight the sum of HNO3 +
• the H2O is used as such, as the dilution H2 ⁇ of the HNO3, as the dilution H2 ⁇ of the H2SO4 or in several of the named forms and a3) the molar ratio of toluene to HNO3 is 0.9-1.5,
• the inorganic phase optionally containing the surface-active substance (s).
• This variant is carried out batchwise or continuously, preferably continuously.
• the procedure can be as follows: The total amount of the reactants is rapidly mixed in a mixing device and fed as a mixture into a reactor.
• the mixing time for a continuous process is generally less than 3 seconds, for example 1 msec. to 2.99 sec., preferably 1 msec. up to 2 sec.
• the reactor is isolated if necessary, largely prevents backmixing and is operated adiabatically.
• the reactor is divided or consists of several chambers or units; at the transitions between The reaction mixture is redispersed in the reactor parts.
• the fully reacted mixture runs off and is separated in a separation vessel; the separation is quick.
• the organic phase is worked up in the customary manner, for example by washing and distillation, or immediately fed to a second nitration.
• the separated inorganic phase is practically free of nitric acid. If this is not the case, in particular with an excess of nitric acid, residual nitric acid can be consumed in a post-reactor with the addition of further toluene in the sense of a reactive extraction.
• the inorganic acid phase largely freed from the nitric acid is preferably fed to flash evaporation using the heat of reaction absorbed and under reduced pressure.
• water is removed from the acid and, preferably, the acid is brought to the inlet concentration and the inlet temperature at the same time. This acid is then immediately suitable as H2SO4 for use in step a) and may contain the surface-active substance (s).
• H2SO4, H2O in the process results in a circular procedure for the H2SO4 and, if applicable, the surface-active substance (s); it may make sense to remove a small part of this H2SO4 in order to keep any contamination at a low level.
• the inorganic phase still contains toluene, nitrotoluene and possibly organic by-products, it may be useful to strip the inorganic phase before the flash evaporation to remove the organics.
• the water subsequently obtained as flash condensate is then of higher purity and its disposal is easier.
• the flash condensate can also be freed of organics, for example by stripping or phase separation, analogously leaving a remaining flash condensate or a water-acid phase with higher purity.
• the organics resulting from the post-reaction of the HNO3 with further toluene as well as from stripping or other material separations, such as phase separation, can be added to the process at a suitable point (toluene, (di) nitrotoluene) or are discharged and disposed of (impurities, by-products).
• the reactants can be fed together, but also individually or as mixtures of two or three of them simultaneously or successively to the reactor equipped with mixing elements.
• the mixing of the starting materials can take place, for example, by adding toluene and nitric acid or, if appropriate, water as separate streams simultaneously or successively to the concentrated, recycled sulfuric acid, it being possible for the nitric acid to be diluted by water and / or sulfuric acid and water.
• Toluene can also be premixed with water and sulfuric acid, and the resulting emulsion is further intensively mixed with nitric acid, which may be mixed with sulfuric acid and / or water.
• the toluene can also be treated with a nitrating acid
• Sulfuric acid, nitric acid and water are mixed intensively and then further treated according to the invention.
• the surface-active substance (s) to be used according to the invention can be added to each of these streams or stream mixtures or can be used separately. Still further variants of the supply of the reactants, their intensive mixing and further treatment are easily recognizable for the person skilled in the art.
• the mixing elements known in the art are suitable for this, for example: 1. static mixers, 2. pumps, 3. nozzles, 4. stirrers or combinations thereof.
• reaction participants nitric acid and toluene as well as sulfuric acid and water and the surface-active substance (s) are mixed with each other as long as the reaction mixture has the composition according to the invention after the total mixing and the mixing takes place largely without backmixing in the intensity according to the invention and in the case of a continuously carried out reaction.
• the intensity of the mixing in the discontinuous mode of operation can also be characterized by the short addition time of the reaction participants, which is 0.001 to 15%, preferably 0.001 to 3% of the time for the reaction between toluene and nitric acid is required.
• the method according to the invention can thus also be carried out batchwise in a stirred tank.
• static mixing elements are preferably present in sections in the reactor, optionally also in the form of spherically shaped fixed internals, such as perforated plates, slotted plates, baffle plates, flow breakers or stirrers or similar internals or organs known to the person skilled in the art for this purpose.
• Examples of continuously operated reactors for the special variant are: tubular reactors with internals for redispersion, such as baffles, baffles, static mixers or stirrers and the like; strongly stirred kettles in a cascade arrangement; Loop reactors with internals as above; Combinations of several of the devices mentioned; other reactors with the same effect, such as chamber reactors with stirrers in each chamber.
• Tubular reactors with internals are preferably used.
• the internals are preferably perforated sheets. All internals represent subdivisions of the entire apparatus, which serve both redispersion and the extensive prevention of backmixing.
• the number of redispersion processes is 2 to 50, preferably 3 to 30, particularly preferably 4 to 20.
• the reaction participants use a mixing energy per liter of the entire reaction mixture of 1 to 80 watts / liter, preferably 1 to 70 W / 1, particularly preferably 1 to 60 W / 1, very particularly preferably 5 to 50 W / 1, added to the reaction system.
• the mixing of the reactants in the special variant takes place in the range from 20 to 120 ° C., preferably 30 to 110 ° C., particularly preferably 40 to 100 ° C. Adiabatic reaction conditions are observed.
• the final temperature depends on the level of the mixing temperature, the proportions of the reactants and the conversion; it generally does not exceed 135 ° C, usually not 125 ° C.
• the content of added nitric acid in the reaction mixture at the time of mixing is in the special variant, based on the sum of nitric acid, sulfuric acid and water, 1 to 8% by weight, preferably 1 to 6% by weight, particularly preferably 1 , 5 to 4 wt .-%.
• Nitric acid can be used in highly concentrated or azeotropically boiling form, but preferably in the form of the approximately 60-65% by weight cheaply available "weak acid".
• the content of sulfuric acid in the reaction mixture at the time of mixing in the special variant is 56 to 85% by weight, preferably 58 to 74% by weight, particularly preferably 60 to 72% by weight .-%, very particularly preferably 61 to 69 wt .-%.
• These figures do not include the process-specific impurities that may be contained in a H2SO4 cycle.
• the amount of one or more surfactants is the above.
• H2SO4 as dilution H2 ⁇ of HNO3 or in several of the forms mentioned.
• H2O is present as both the H2SO4 and the HNO3 as dilution H2 ⁇ .
• this H2SO4 concentration of the used acid should be 62 to 74% by weight, preferably 64 to 72% by weight, particularly preferably 66 to 70% by weight.
• the re-used sulfuric acid is reused by 0.6 - 7 percentage points, in many cases by
• the heat of reaction taken up by the running H2SO4 as a result of the adiabatic reaction is preferably used and under reduced pressure in the range from 1 to 100 mbar, preferably at 5 -80 mbar, particularly preferably 10-
• the H2SO4 obtained is suitable for use in step a).
• the removal of water by distillation is preferably carried out in such a way that the temperature and concentration of the concentrated H2SO4 correspond directly to the values required in step a).
• Heat of reaction makes the process according to the invention more economical than the known processes for the preparation of nitrotoluenes.
• H 2 SO 4 (wt%) 68.69 69.01 69.69 draining H2SO4 (wt%) 66.0 67.0 68.0
• Flash evaporation pressure 40 50 60 (approx. Mbar)
• the molar ratio of toluene to HNO3 is generally 0.9 to 1.5.
• the molar ratio of toluene to nitric acid is preferably 1.0 to 1.5, particularly preferably 1.03 to 1.3, very particularly preferably 1.05 to 1.2.
• other molar ranges e.g. 0.9-1.2 mol, preferably 0.9 to 1.05 mol, particularly preferably 0.95 to 1 mol of toluene per mol of nitric acid is permissible.
• toluene and HNO3 are introduced into the process and mononitrotoluene and water of reaction are discharged, while the H2SO4 / H2O mixture described, which may contain the surface-active substance (s), the reac- represents medium. Since dilute nitric acids are advantageously used in the technical implementation, depending on the prices of the available nitric acids, dilution H2O of the HNO3 must also be removed in addition to the water of reaction.
• the organic phase obtained in the separation of the reaction mixture can be worked up to pure mononitrotoluene or fed to the production of dinitrotoluene.
• at least molar amounts of toluene or a small molar excess will be used in order to both consume the HNO3 and to suppress the second nitration; any
• Excess toluene is distilled off from the separated organic phase.
• the organic phase can be washed beforehand in order to separate water, acid or alkali-soluble impurities, such as inorganic and organic acids and phenolic impurities.
• oxidation products phenolic body, oxidation of the CH3 group
• dinitrotoluenes is also strongly suppressed. However, these dinitro toluenes do not interfere if a second nitration is provided anyway; therefore, in such cases, a toluene deficit may also be used.
• Another special variant of the nitriding process according to the invention in the presence of surface-active substances relates to the production of mononitrohalobenzenes.
• the second special variant accordingly relates to a process for the continuous or discontinuous production of mononitrohalobenzenes by reacting halobenzenes with an HN ⁇ 3 / H2S ⁇ 4 / ⁇ 2 ⁇ mixture in the presence of 0.5 to 20,000 ppm of one or more surface-active substances to form essentially the mononitrohalobenzenes and Water of reaction, characterized by the steps a) Feeding the reactants halobenzene, HNO3, H2SO4 and H2O in any order into a reactor equipped with mixing elements, where
• H2O is used as such, as dilution H2 ⁇ of HNO3, as dilution H2 ⁇ of H2SO4 or in several of the forms mentioned, and
• Halogenobenzenes in the sense of the invention are chlorobenzene, o-, m-, p-dichlorobenzene, o-, m-, p-chlorotoluene and bromobenzene, preferably chlorobenzene and o-, m-, p-dichlorobenzene, particularly preferably chlorobenzene and o-dichlorobenzene .
• This variant can also be carried out continuously or batchwise, preferably continuously.
• the continuous procedure can be carried out, for example, as for the first special variant, with toluene replacing halogenobenzene.
• the reactants are mixed in the second special variant in the range from 60 to 160 ° C., preferably 70 to 140 ° C., particularly preferably 80 to 120 ° C. Adiabatic reaction conditions are observed.
• the final temperature depends on the level of the mixing temperature, on the quantitative ratios of the reactants and on the conversion; it generally does not exceed 180 ° C, usually not 160 ° C.
• the content of added nitric acid in the reaction mixture at the time is 1 to 8% by weight, preferably 2 to
• the content of sulfuric acid in the reaction mixture at the time of mixing is, based on the sum of nitric acid, sulfuric acid and water, in the second special variant 56 to 85% by weight, preferably 56.5 to
• the H2SO4 concentration of the used acid in the context of the second special variant should be 60 to 85% by weight, preferably 68 to 80% by weight, particularly preferably 70 to 78% by weight.
• the re-used sulfuric acid is concentrated by 0.6 to 7.5 percentage points, in many cases by 1.7 to 4.2 percentage points.
• the heat of reaction taken up by the flowing H2SO4 is used and worked under reduced pressure, for example at 40 to 150 mbar, preferably at 40 to 120 mbar, particularly preferably at 50-100 mbar. For example, this can also be carried out in the form of flash evaporation.
• the molar ratio of halogenobenzene to HNO3 is generally 0.9 to 1.5.
• the molar ratio of halogenobenzene to nitric acid is preferably 1.0 to 1.5, particularly preferably 1.01 to 1.3, very particularly preferably 1.05 to 1.2.
• other ranges are also, for example 0.9 to 1.2 mol, preferably 0.9 to 1.05 mol, particularly preferably 0.95 to 1 mol, halogenobenzene permissible per mole of nitric acid.
• the organic phase obtained in the separation of the reaction mixture can be worked up analogously to the first special variant.
• Acid phase 121 l / h with 4.20 g mononitrotoluenes per kg acid phase
• a stream consisting of 187.8 kg / h of H 2 SO 4 70% and 8.7 kg of HNO3 67% and a stream of 11.5 kg / h were simultaneously introduced into a tubular reactor with perforated plates as redispersing organs at 110.degree. h chlorobenzene fed; Alkanesulfonate was not used. After a residence time of about 35 seconds, the fully reacted reaction mixture left the reactor.
• Acid phase 121 l / h with 4.20 g mononitrotoluenes per l acid phase.

Landscapes

• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
• Low-Molecular Organic Synthesis Reactions Using Catalysts (AREA)

Applications Claiming Priority (5)

Publications (1)

Family

ID=26041268

Family Applications (1)

Country Status (16)

Families Citing this family (9)

Family Cites Families (8)

• 1998
  • 1998-10-21 IL IL13540298A patent/IL135402A0/xx unknown
  • 1998-10-21 CA CA002308288A patent/CA2308288A1/en not_active Abandoned
  • 1998-10-21 JP JP2000518938A patent/JP2001521920A/ja active Pending
  • 1998-10-21 ID IDW20000826A patent/ID24977A/id unknown
  • 1998-10-21 AU AU10315/99A patent/AU741332B2/en not_active Ceased
  • 1998-10-21 WO PCT/EP1998/006688 patent/WO1999023061A1/de not_active Application Discontinuation
  • 1998-10-21 PL PL98340030A patent/PL340030A1/xx not_active Application Discontinuation
  • 1998-10-21 SK SK620-2000A patent/SK6202000A3/sk unknown
  • 1998-10-21 US US09/530,204 patent/US6242657B1/en not_active Expired - Fee Related
  • 1998-10-21 HU HU0100200A patent/HUP0100200A3/hu unknown
  • 1998-10-21 CN CN98810539A patent/CN1277601A/zh active Pending
  • 1998-10-21 EP EP98952730A patent/EP1028937A1/de not_active Withdrawn
  • 1998-10-21 BR BR9814108-2A patent/BR9814108A/pt not_active IP Right Cessation
  • 1998-10-30 TW TW087118011A patent/TW466223B/zh active
• 2000
  • 2000-04-19 MX MXPA00003884 patent/MXPA00003884A/es unknown
  • 2000-04-28 NO NO20002247A patent/NO20002247D0/no not_active Application Discontinuation

Non-Patent Citations (1)

Also Published As

Similar Documents

Legal Events