Abstract: A process for the preparation and purification of nitroaromatics by nitration of the corresponding aromatics and subsequent melt crystallization. The residual melts which occur are recycled.

Abstract: Aromatic nitration reactions and, more specifically, a process for nitrating toluene to produce dinitrotoluene in the absence of any dipolar aprotic solvent.

Abstract: A continuous process for the preparation of isomeric mixtures of dinitrotoluene by a single stage nitration of toluene under adiabatic conditions. The reaction enthalpy is used for the removal by distillation of the water of reaction formed during nitration. In this process, toluene is reacted with a nitrating acid having from about 80 to about 100% by weight of an inorganic component having a specified composition and from about 0 to about 20% by weight of an organic component having a specified composition.

Abstract: Improved process for preparing dinitrotoluene by reacting toluene with concentrated nitric acid. The process reacts toluene with a large excess of concentrated nitric acid, in the presence of a select hydrated nitrate salt which is effective in minimizing explosive hazards, to produce a product which has substantially reduced by-product content.

Abstract: Process for preparing dinitrotoluene by reacting toluene with concentrated nitric acid. The process reacts toluene with a large excess of concentrated nitric acid at selected conditions to produce a product which has substantially reduced by-product content.

Abstract: The present invention relates to a process for producing an aromatic nitro compound by introducing a nitrogen oxide gas and ozone-containing oxygen or air into a halogenated organic solvent dissolving or suspending therein an aromatic compound, thereby subjecting the aromatic compound to nitration. By the use of a system comprising the nitrogen oxide and ozone-containing oxygen or air as the nitrating agent, the aromatic nitro compound can be produced under mild conditions without using any mineral acid. In addition, the various disadvantages due to the use of mineral acid in the conventional process can be avoided by the process of the present invention.

Abstract: A process for removing organic compounds, including nitro-hydroxy-aromatic compounds and amines, from alkaline wastewater, and in particular from wastewater generated in the production of nitrobenzene, dinitrobenzene, nitrotoluene and dinitrotoluene. The process involves distilling the alkaline wastewater steam at or near atmospheric pressure until it is concentrated five to twenty-five fold. The distillate includes water, which may be discharged to the environment, subjected to biological treatment, or recycled for use in the production process; and volatile organics, which are phase separated from the aqueous portion of the distillate and which may be recycled to the crude product stream. The concentrated residue from the distillation may be incinerated or subjected to biological treatment.

Abstract: An improved process for the nitration of a substituted or unsubstituted benzocyclobutene compound in a reaction mixture comprising a nitrating agent, an unhalogenated carboxylic acid anhydride, clay and a solvent to produce a corresponding nitrobenzocyclobutene compound, is that wherein:(a) the solvent has a density above that of the nitrating agent or an extractable precursor thereof;(b) the reaction mixture is heated at a temperature such that solvent is removed from the reaction mixture to a site outside the reaction mixture to extract nitrating agent or extractable precursor thereof; and(c) the thus-extracted nitrating agent or precursor thereof is fed into the reaction mixture to nitrate the benzocyclobutene compound.

Abstract: Pure or substantially enriched 2,4- and 2,6-dinitrotoluene can be isolated from a mixture containing these isomers if such a mixture is distilled under a pressure of 0.5 to 20 mbar at a temperature of 80.degree. to 200.degree. C. with exclusion of reducing conditions.

Abstract: Described herein is a one pot continuous improved process for preparing dinitrotoluene by reacting toluene with concentrated nitric acid.

Abstract: Described herein is a one pot continuous process for preparing dinitrotoluene by reacting toluene with concentrated nitric acid.

Abstract: Described herein is a process for separating an acid impurity from a solution containing acid and a nitro substituted aromatic compound by contacting the solution with at least one molten nitrate salt.

Abstract: Described herein is a continuous process for preparing dinitrotoluene by reacting toluene with dilute nitric acid to produce mononitrotoluene, then reacting the mononitrotoluene with concentrated nitric acid to produce dinitrotoluene.

Abstract: The present invention relates to a process for purifying an aromatic nitration product mixture comprising a nitrated aromatic compound, water, and nitric or sulfuric acid which comprises without regard to sequence: (a) removing at least a portion of said water from said product mixture by contacting and reacting said water in said mixture with magnesium nitrate trihydrate to form magnesium nitrate pentahydrate or magnesium nitrate hexahydrate and removing said magnesium nitrate pentahydrate or magnesium nitrate hexahydrate from said nitrated aromatic compound in said product mixture, and (b) removing at least a portion of said acid from said product mixture by contacting and reacting said acid with an ionic or non-ionic absorbent to form a reacted absorbent and removing said reacted absorbent from said nitrated aromatic compound in said product mixture.

Abstract: Sulphuric and nitric acids present in dinitrotoluene are separated from the dinitrotoluene by adding up to 10 wt. % water (based on quantity of dinitrotoluene) to the mixture of dinitrotoluene, sulphuric acid and nitric acid, mixing and separating the aqueous phase containing nitric and sulphuric acids. The mixtures treated by this process generally contain up to 5 wt. % nitric acid and up to 6 wt. % sulphuric acid.

Abstract: Aromatic nitration reactions and, more specifically, a process for nitrating toluene to dinitrotoluene. The process involves a liquid phase nitration reaction of anhydrous nitric acid and toluene in a molar ratio of between about 5:1 and about 9:1 of nitric acid to toluene in a reactor at a reaction temperature of between about 40.degree. C. and about 70.degree. C., in the absence of sulfuric acid and in the absence of any dipolar organic solvent, to produce a mixture containing dinitrotoluene, and isolating said dinitrotoluene by contacting said mixture with a phase separating effective amount of an alkali or alkaine earth metal nitrate salt to cause phase separation of said dinitrotoluene.

Abstract: Dinitrotoluenes are prepared by reacting mononitrotoluene(s) with nitric acid, in liquid phase, in the presence of an inorganic and acidic solid including at least one component selected from among orthophosphoric acid, pyrophosphoric acid, metaphosphoric acid, a metal dihydrogen phosphate, a metal hydrogen phosphate, a metal orthophosphate or a metal pyrophosphate, such metal cations having from 1 to 5 positive charges.

Abstract: This invention relates to the preparation of a mixture of nitroaromatic compositions, particularly a mixture of mononitrobenzene and dinitrotoluene. The conitration of a mixture of aromatic hydrocarbons is accomplished by contacting the mixture of hydrocarbons with nitric acid, in the absence of sulfuric acid, at temperatures of from about 40.degree. to 70.degree. C. By the use of nitric acid alone, one avoids the heterogeneous nitration associated with the use of sulfuric acid and thereby one can effectively produce a reaction mixture containing mononitrobenzene and dinitrotoluene.

Abstract: This invention relates to a process for nitrating toluene to dinitrotoluene and phase separation of the product using an inorganic salt as a phase separation agent.

Abstract: This invention comprises a process for separating the minor dinitrotoluene isomers, 2,3-dinitrotoluene and 3,4-dinitrotoluene from a feed mixture comprising 2,4- and 2,6-dinitrotoluene, and the minor isomers, which process comprises contacting the mixtures at adsorption conditions with an adsorbent comprising a Y type, or dealuminated Y type, zeolite, cation exchanged with Na, Ca or H, thereby selectively adsorbing the 2,3- and 3,4- isomers or 2,4- and 2-6 isomers, respectively. The remainder of the feed mixture is removed from the adsorbent and the minor isomers are recovered by desorption at desorption conditions with a desorbent material comprising an alcohol, ketone or an ester.

Abstract: In the production of dinitrotoluene by a two-stage reaction of toluene with nitric acid in the presence of sulphuric acid, wherein toluene is nitrated to mononitrotoluene in the first stage using spent acid from the second stage, and the mononitrotoluene is nitrated to dinitrotoluene in the second stage using concentrated spent acid from the first stage, the improvement which comprises concentrating spent acid under vacuum in an indirectly-heated evaporator and feeding mononitrotoluene into the superheated vapor of the evaporator.

Abstract: In a method for denitrifying the nitric acid- and nitrous acid-containing spent acid phase from the nitration of an aromatic hydrocarbon by the mixed acid process which comprises forming a denitrification reaction medium by contacting the spent acid phase with an aromatic hydrocarbon under nitration reaction conditions to recover the nitric acid by the formation of a nitroaromatic hydrocarbon, the improvement which comprises(a) adding an amount of aromatic hydrocarbon which is slightly less than or equal to the stoichiometric amount necessary to deplete the spent acid phase of nitric acid,(b) photometrically monitoring the denitrification reaction medium for the appearance of a dark red to black color, and(c) upon detection of such color, adjusting the aromatic hydrocarbon:nitric acid molar ratio in the denitrification reaction medium to eliminate the color by reducing the aromatic hydrocarbon feed rate, or adding nitric acid to the denitrification reaction medium.

Abstract: This invention pertains to a process for extracting a nitroaromatic composition from a nitration medium containing nitric acid, water, and nitroaromatic. The process comprises contacting the nitration medium with nitric oxide under conditions such that the nitric oxide will react with the nitric acid to form nitrogen dioxide and water. Gaseous nitrogen dioxide is removed from the reaction medium and accordingly, the dissolved nitroaromatic present in the nitration medium separates to form an organic phase which then can be removed by decantation. Typically, one mole of nitric oxide is added to the nitration medium for every two moles of nitric acid present in said medium. Reaction conditions normally are from about 0.degree. to 90.degree. C.

Abstract: This invention comprises a process for separating 2,4-dinitrotoluene from a feed mixture comprising 2,4-dinitrotoluene and at least one isomer thereof, which process comprises contacting the mixture at adsorption conditions with an adsorbent comprising an X or Y type zeolite cation exchanged with a cation in the group K, Na, Ca, Ba, Li or Mg, thereby selectively adsorbing the 2,4-dinitrotoluene. The remainder of the feed mixture is removed from the adsorbent and the 2,4-dinitrotoluene is recovered by desorption at desorption conditions with a desorbent material comprising a C.sub.3 to C.sub.5 alcohol, a ketone, toluene, an ester or a nitrocompound.

Abstract: The present invention relates to improvements in processes of preparing dinitrated aromatic compounds, particularly dinitrated aniline and dinitrated substituted aniline compounds, employing relatively dilute and then more concentrated nitric acid as the nitrating agent.

Abstract: This invention relates to a process for removing trinitrocresols and picric acid contaminants from a wastewater stream generated in the production of nitroaromatics, particularly dinitrotoluene, by the mixed acid technique. The process involves contacting the crude dinitrotoluene generated by the mixed acid technique with an alkaline medium to generate an alkaline wash water containing water soluble nitrocresols and picric acid therein. This wastewater then, is separated from the organic component or may be recycled for contact with further quantities of crude dinitrotoluene product from the reactor. When the concentration of the water soluble salts of trinitrocresols and picric acid is of sufficient concentration, the wash water is treated with aqueous acid in sufficient proportion to reduce the pH to a level from 3-4.

Abstract: This invention relates to a process for removing nitrocresols and picric acid contaminants from a wastewater stream generated in the production of nitroaromatics, particularly dinitrotoluene, by the mixed acid technique. The process involves contacting the crude dinitrotoluene generated by the mixed acid technique with an alkaline medium to generate an alkaline wash water containing water soluble nitrocresols and picric acid therein. This wastewater is separated from the organic component and recycled for contact with further quantities of crude dinitrotoluene product from the reactor. When the concentration of the water soluble salts of nitrocresols and picric acid is of sufficient concentration the wash water is treated with aqueous acid in sufficient proportion to convert the water soluble salts to water insoluble organics. After treatment with acid, the organic material is separated from the wastewater and the organics incinerated.

Abstract: A method is provided for denitrifying the aqueous spent acid of mononitration. The nitric acid in the aqueous spent acid is recovered by adiabatically reacting greater than a stoichiometric amount of a mononitroaromatic hydrocarbon with the aqueous spent acid which has been fortified to a nitric acid concentration of at least about 2 wt %. The denitrification method is useful in treating the aqueous spent acid phase from the mononitration stage of a dinitrotoluene process.

Abstract: The novel compound, tetranitroglycoluril, is described having a stability under vacuum of 6 cm.sup.3 /g/100 hours at 110.degree. C. The compound exhibits a rate of detonation at least equal to 9,073 meters per second under a density charge of 1.94, has a decomposition temperature of about 200.degree. C. and is stable at a temperature of up to 100.degree. C. at normal pressure. It may be dried at 65.degree. C. The brisance value by the Friedrich's formula is 159.7.times.10.sup.6. The rate of detonation and brisance value are superior to octogen.

Abstract: Dinitrotoluene, which is produced by mixed acid nitration of toluene, is purified in a way which produces a product suitable for conversion to toluene diamine and a less environmentally objectionable by-product stream. The process involves contacting a crude dinitrotoluene stream containing by-product nitrophenolic materials with an alkaline material and monitoring the pH such that dinitroorthocresol by-product is maintained in the organic phase while the trinitroorthocresol by-products are converted to water-soluble materials and removed with an aqueous phase.

Abstract: Aromatic hydrocarbons are nitrated by reacting the aromatic hydrocarbon in a nitrogen tetroxide-containing liquid reaction medium, in the presence of a beta-dicarbonyl compound having a "W" configuration with a carbonyl group at each apex of the "W", preferably at a pressure and temperature sufficient to maintain the nitrogen tetroxide in the liquid state. Addition of an inert organic co-solvent to the liquid nitrogen tetroxide for the metal acetylacetonate promoted nitration of benzene essentially eliminates the production of dinitrobenzenes.

Abstract: A method for preparing substantially pure 2,4-DNT isomer from its admixture with other DNT isomers which comprises contacting the isomer mixture with aqueous sulfuric acid at an elevated temperature, separating excess DNT isomer mixture from the sulfuric acid phase and cooling the sulfuric acid phase.

Abstract: The invention relates to a method of eliminating or substantially reducing the amount of cyanide formed in a polynitroaromatic, e.g. dinitrotoluene process. The invention comprises removing the nitrophenolic material from the mononitroaromatic formed in a first stage nitration of toluene prior to feeding the mononitroaromatic to the subsequent nitration zones.

Abstract: A process has been developed for isolating aromatic dinitro compounds by using nitric acid in specified concentrations in different portions of a rectifying column and separating off the mixture of aromatic dinitro compounds from the sump of the rectifying column.

Abstract: This invention relates to an improvement in a process for the manufacture of a nitroaromatic compound produced by the mixed sulfuric-nitric acid nitration method. The improvement resides in the refining of the aqueous acid mixture and comprises the following sequential steps: (a) contacting the mixed aqueous acid mixture, after nitration, with an oxidizing or a reducing agent under conditions effective for removing contaminant nitrous acid; (b) contacting the aqueous acid mixture in step (a) with feed aromatic compound to remove contaminant organics and residual nitric acid and then, if necessary, (c) contacting the remaining acid mixture with sufficient oxidizing agent under oxidizing conditions to remove residual organic components.

Abstract: The present invention relates to improvements in processes of preparing dinitrated .[.aromatic compounds, particularly dinitrated aniline and dinitrated substituted aniline compounds, employing relatively dilute and then more concentrated nitric acid as the nitrating agent.]. .Iadd.aniline and substituted phenol compounds in a two-step process, employing, in the first or mononitration step the spent nitric acid from the second of dinitration step. .Iaddend.