Abstract:
This invention relates to an improved process for the recovery and regeneration of nitric acid from spent acid obtained from the mixed acid nitration of aromatic compounds. In that process a mixed acid of sulfuric acid and nitric acid is contacted with an aromatic composition at a temperature and pressure sufficient for producing a nitroaromatic composition and a spent acid containing unreacted nitric acid, sulfuric acid and solubilized nitroaromatic compounds in said spent acid. The improvement comprises initially heating the spent acid to a temperature of from about 120.degree. to 200.degree. C. for a time sufficient to convert said nitroaromatics in said spent acid to a nitroaromatic composition having a boiling point greater than 300.degree. C. at atmospheric pressure and then flash distilling the hot spent acid containing nitroaromatics compositions at a pressure from about 5 to 15 psia and temperature of 150.degree. to 200.degree. C. Nitric acid is removed as an overhead vapor fraction in preselected concentration and sulfuric acid and nitroaromatics are obtained as a bottoms liquid stream from said flash distilling step. The nitroaromatics are then removed from the liquid stream. Sulfuric acid obtained from this process is essentially free of color and suited for concentration.
Abstract:
Substituted fluorobenzenes which are produced in aprotic, polar solvents or in mixtures which contain such solvents can be obtained by extracting the substituted fluorobenzenes from the solvents or solvent mixtures with aliphatic extracting agents and then seaprating the extracting agents from the substituted fluorobenzenes.
Abstract:
Pentachloronitrobenzene (PCNB) which initially contains in excess of 0.5% hexachlorobenzene (HCB) is purified by distilling the impure PCNB at a temperature between 100.degree.-250.degree. C. and a pressure below or at atmospheric pressure to obtain a PCNB product having a HCB content lower than 0.5%, and preferably lower than 0.1%.
Abstract:
The invention relates to a process for extracting nitrohydroxyaromatics from aqueous solutions. In this process, the extracting agent used is an amine salt which comprises an aliphatic amine having a total carbon number of 10 to 75 and a strong acid. The amine salt can be employed undiluted or diluted with an organic solvent.
Abstract:
A process of recycling nitrated by-products formed during the manufacture of the compound of the formula ##STR1## and salts thereof wherein J is ##STR2## and further wherein: R.sup.1 is fluorine, chlorine, bromine, or iodine or a trifluoromethyl group;R.sup.2 is a hydrogen atom, a fluorine, chlorine, bromine or iodine atom or a trifluoromethyl group;R.sup.3 is a hydrogen atom, a C.sub.1 -C.sub.4 alkyl group, a trifluoromethyl group, a cyano group or a fluorine, chlorine, bromine or iodine group; X is ##STR3## R.sup.4 is R.sup.5 or an acyl radical of the formula ##STR4## wherein Alk is a C.sub.1-6 alkyl group; R.sup.5 is a hydrogen atom or a C.sub.1-6 alkyl group optionally substituted with either one or more halogen atoms or a phenyl group;B is a C.sub.1-10 alkyl, OR.sup.7 or SR.sup.7 ;y is 1 to 4;R.sup.6 is a hydrogen atom or a C.sub.1-2 alkyl group;R.sup.7 is hydrogen, or a C.sub.1-8 alkyl group, a C.sub.3-8 cycloalkyl group, an agronomically acceptable cationic salt, or a ##STR5## wherein n is 0 to 3 and Z is selected from the group consisting of halogen, a C.sub.1-10 alkyl or alkoxy group, cyano, nitro, and trifluoromethyl; andR.sup.8 is R.sup.5 or a C.sub.1-6 alkoxy group. The process comprises 2 stages. In the first stage, the nitrated by-products are reduced. In the second stage, the reduced compounds are diazotized and the diazonium group is replaced with a hydrogen atom.
Abstract:
In a process for preparing aromatic monocarboxylic acids by oxidation of toluene or of toluenes substituted in the nucleus, the starting substances are reacted in the liquid phase with oxygen or with a gas containing oxygen, at a temperature of 80.degree.-180.degree. C. and a pressure of 5 to 50 bar in the presence of acetic acid as diluent and a soluble cobalt and/or manganese salt in combination with a bromide, and the aromatic monocarboxylic acids are then obtained by solid-liquid separation of the cooled reaction mixture.To reduce the dimensions of the oxidation reactor, for which particularly corrosion-resistant materials are necessary, and to isolate the target products in high yield and purity, as well as to reduce the technical complexity and cost of the treatment of the amounts of solvents that are yielded, relatively small amounts of acetic acid are used as solvents or diluents, namely at a ratio by weight of the alkyl aromatic being oxidized and acetic acid of 0.5:1 to 6:1. Not until the reaction has ended is the dilution, which is necessary for the isolation of the target product by solid-liquid separation of the cooled reaction mixture, performed by the addition of dilute aqueous acetic acid or of the washing filtrate from a preceding oxidation run. A typical example is the preparation of p-tert-butylbenzoic acid from p-tert-butyltoluene by the method described.
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:
Crude phenoxybenzoic acid herbicide, e.g., acifluorfen, having one or more undesirable isomer/by-product impurities associated therewith is separated therefrom employing an inert solvent which is selective for the isomers/other by-products.
Abstract:
A process for the preparation and recovery of m,m'-dinitrobenzophenone and which comprises reacting benzophenone with nitric acid in oleum; adjusting the reaction product to a water content from 12 to 30 weight percent; and extracting the m,m'-dinitrobenzophenone with a chlorinated hydrocarbon solvent.
Abstract:
A process is disclosed for separating nitrated phenolic compounds from other nitrated and unnitrated phenolics by treating a mixture of the phenolics with a metal halide salt. The metal halide salt preferentially forms a complex with one of the phenolics over other related phenolics in the mixture. The preferentially-formed complex of one of the phenolics may then be isolated from the mixture and the complex decomposed to provide a product substantially enriched in, or substantially entirely composed of, one phenolic. The process is particularly suitable for resolving a mixture comprising phenol or cresol from their ortho-nitrated derivatives, or a mixture of two isomeric nitrated phenols or cresols or a mixture of mono-and dinitrated phenols or cresols.