Abstract: 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(a) adjusting the pH of the aqueous alkaline waste stream containing nitroaromatic and nitrophenolic compounds to a range from about 2 to 4.5,(b) contacting the acidic aqueous stream with sufficient hydrogen peroxide and ferrous ion under conditions to effect oxidation of the nitrophenolic compounds,(c) adjusting the acidic, oxidized aqueous waste stream having a reduced nitrophenolic content to about pH .gtoreq.4, and(d) contacting the aqueous waste stream with a carbon adsorbent.

Abstract: 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.

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 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 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: An improved method of mashing and lautering. A mash is formed having a high malt to water ratio in the range of about 0.30 to 0.45 to 1. After mashing, and prior to lautering, the mash is diluted with water to produce an equivalent malt-to-water ratio below 0.25 to 1 and generally in the range of about 0.19 to 0.22 to 1. The diluted mash is then lautered by standard procedures to separate the wort from the spent grains. Due to the high concentration of malt in the mash, the conversion yield, or the amount of dissolved solids extracted from the malt, is increased and the dilution prior to lautering not only reduces the time for lautering but also upsets the concentration equilibrium between the liquids and grains, causing a further improvement in the extract yield.

Abstract: A method of reducing foaming of a liquid containing dissolved carbon dioxide during filtering. The carbonated liquid to be filtered is adjusted in pH to a value of 6.5 to 8.0 by the addition of an alkaline material which reacts with the dissolved carbon dioxide to remove the carbon dioxide from solution. The elimination of the dissolved carbon dioxide results in decreasing foaming during filtering and substantially increases the rate of filtration.