Air Products and Chemicals, Inc.

John Edward Sawicki

Juan Jesus Burdeniuc

Thomas A Johnson

Richard Van Carr

Malee Leeaphon

Baldomero Casas

Thomas Albert Johnson

Glenn T Hong

Bernard A Toseland

Frederick L Herman

Chiung-Yuan Huang

William R Killilea

Steven B Peter

Keith B Adams

Michael C Pohl

This invention relates to an improvement in a process for the production of dinitrotoluene and particularly to the recovery of dinitrotoluene and organic by-products from the wastewater and wash waters generated in the process. Wastewater and wash water streams contaminated with residual levels of mononitrotoluene, dinitrotoluene, and organic by-products, formed in the purification process, are contacted with toluene. An organic phase and an aqueous phase are generated. The phases are separated and the dinitrotoluene recovered from the organic phase.

Toluene extraction of dinitrotoluene wash water

A single step wet oxidation process for treating wastewaters containing organic species, with or without heteroatoms, and anions of strong acids, e.g. sulfate or phosphate ion, or cations of strong bases, e.g., sodium, potassium or calcium ions, and which may contain ammonium ion and/or nitrate ion in addition to added ammonium ion and/or nitrate ion was developed which on thermal treatment near the critical temperature of water removes substantially all the COD and nitrogen through conversion to water, carbon dioxide or carbonate species, nitrogen gas and small amounts of nitrous oxide. Key to the success of the process is the balancing of all reducing species with an equivalent amount of oxidizing species and the balancing of all strong acid anions with strong base cations and including at least 0.06 acetate ion for moles of nitrate in the wet oxidation process.

Treatment of water containing organic wastes with ammonium nitrate

A single step wet oxidation process for treating wastewaters containing organic species, with or without heteroatoms, and anions of strong acids, e.g. sulfate or phosphate ion, or cations of strong bases, e.g., sodium, potassium or calcium ions, and which may contain ammonium ion and/or nitrate ion in addition to added ammonium ion and/or nitrate ion was developed which on thermal treatment near the critical temperature of water removes substantially all the COD and nitrogen through conversion to water, carbon dioxide or carbonate species, nitrogen gas and small amounts of nitrous oxide. Key to the success of the process is the balancing of all reducing species with an equivalent amount of oxidizing species and the balancing of all strong acid anions with strong base cations. The former ensures good removal of organic species, ammonium ion and nitrate ion. The latter ensures maintaining the pH in the range of from 1.5 to 8 thus avoiding severe corrosion problems and regions of pH where rate of reaction of the oxidizing species with reducing species is slow.

A process for removing nitroaromatic and nitrophenolic compounds from an alkaline wastewater stream generated in a process for the nitration of aromatic compounds by the mixed acid technique, which comprises

Tandem waste stream treatment for the removal of nitroaromatics and

This invention relates to improved wet oxidation process for the destruction of organic components in a wastewater stream contaminated with inorganic salts. In wet oxidation, the wastewater stream is contacted with an oxygen-containing water stream at elevated temperatures and pressures. The improvement for treating aqueous wastewater streams contaminated with inorganic salts wherein the organic contaminants are present in an amount from about 0.5 to 2% by weight resides in oxidizing the organic components in a tubular reactor at a temperature ranging from 325.degree. C. to not more than 370.degree. C. and a pressure ranging from 220 to 345 bar. The oxidation reaction is carried out in a reaction time of 5 minutes or less.

Wet oxidation of aqueous streams

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

Recovery of nitric acid from nitration spent acid by toluene extraction

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.

Precipitative removal of nitrocresols from dinitrotoluene waste streams

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. Also, in a method for producing dinitrotoluenes which comprises:

High purity 2,4-dinitrotoluene from toluene nitration process

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.

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Breinigsville, PA, United States of America

John Edward Sawicki