Abstract: A process for the continuous preparation of 3,3'-dichlorobenzidine dihydrochloride from 2,2'-dichlorohydrazobenzene by treatment with aqueous sulfuric acid, which comprises treating the 2,2'-dichlorohydrazobenzene, dissolved in a water-immiscible aromatic solvent, continuously at temperatures of from about 20.degree. to about 50.degree. C. in the presence of an alkali metal salt of an alkyl (C.sub.8 -C.sub.23)polyglycol ether sulfate, with such an amount of from about 50 to about 80 % strength aqueous sulfuric acid that the suspension formed remains conveyable, subsequently diluting the suspension emerging from the reaction zone with water, again continuously, and subsequently heating the suspension to a temperature of from about 90.degree. to about 95.degree. C.

Abstract: The invention provides a process for the preparation of p-nitrophenetole with high yields and in an especially pure form from p-chloronitrobenzene and ethanol by heating to a temperature of from 60.degree. to 80.degree. C. with addition of alkali metal hydroxide and a phase transfer catalyst.

Abstract: Crude 3,4,3',4'-tetraaminodiphenyl (TAD) prepared by ammonolysis of 3,3'-dichlorobenzidine in the presence of mainly Cu catalysts is purified by a process in which(a) after its isolation from the preparation process crude TAD is treated with an aqueous NH.sub.3 solution and, if desired, TAD thus treated is then(b) dissolved and reprecipitated in water in the presence of adsorbents and also of a water-soluble reducing agent.Compared with relevant processes of the state of the art, the process produces a higher yield of pure TAD and it is also simpler to carry out.

Abstract: Process for the preparation of 4-phenoxyphenols of the formula ##STR1## in which R.sup.1 through R.sup.5 are hydrogen, halogen or alkyl, by diazotization of amines of the formula ##STR2## in a hydrochloric acid medium, and boiling in aqueous sulfuric acid at 110.degree. to 150.degree. C.

Abstract: Nitrosation agent(s), contained as by-products in nitrated aromatic compounds after nitration with nitric acid or nitration acid, are removed by a water treatment, wherein the water is distilled off at least partially in vapor form, advantageously under reduced pressure. In the further reaction of the nitrocompounds treated in this manner undesired nitrosamines are practically not formed. The process is especially suitable for the manufacture of 4-di-n-propylamino-3,5-dinitrobenzotrifluoride (Trifluralin), a valuable herbicide, substantially free from nitrosamine(s).

Abstract: A process for preparing 5-chloro-2-nitrophenol from 2,4-dichloronitrobenzene and excess alkali metal hydroxide in the presence of aprotic polar solvents at 20.degree. to 150.degree. C.

Abstract: 1,3,5-trichlorobenzene is manufactured by treating 5-chloro-1,3-dinitrobenzene and/or 3,5-dichloronitrobenzene with chlorine, at a temperature from about 200.degree. to 270.degree. C., preferably from about 230.degree. to 250.degree. C. The resulting process product is an intermediate, for example in plant protection.

Abstract: The catalytic hydrogenation of o-nitro-chlorobenzene in aqueous alkali metal hydroxide solution with addition of an aromatic non-watermiscible solvent at an elevated temperature and under pressure using a noble metal catalyst and a polycyclic quinone as a co-catalyst leads to high and well-reproducible yields of 2,2'-dichloro-hydrazobenzene when the quinone is a derivative of anthraquinone, especially a hydroxy-anthraquinone. The product is obtained in so high a quality that it can be transformed without isolation or purification into 3,3'-dichlorobenzidine.

Abstract: 2,4-DINITROANILINE IS OBTAINED IN HIGH YIELD AND QUALITY IN A SAFE REACTION BY INTRODUCING 4-CHLORO-1,3-DINITROBENZENE INTO AT LEAST THREE-FOLD STOICHIOMETRIC AMOUNT OF AQUEOUS AMMONIA OF A CONCENTRATION OF 15 TO 40% BY WEIGHT AT A TEMPERATURE OF 60.degree. TO 90.degree. C.

Abstract: Preparation of chlorohydroquinone by adding hydrogen chloride to p-benzoquinone, wherein a 1 to 20 % by weight solution of p-benzoquinone in benzene is treated discontinuously or continuously with hydrogen chloride at a hydrogen chloride pressure of from 1 to 6 atmospheres gauge, at a temperature of from 40.degree. to 80.degree.C, the residence time being from 1 to 4 hours and the chlorohydroquinone is isolated in known manner.

Abstract: Preparation and isolation in substance of ortho-aminothiphenols by the reduction of ortho-chloronitrobenzenes with hydrogensulfides or sulfides, subsequent neutralization in the presence of sulfites, hydrogensulfites or disulfites, separation and following purification of the crude products. The ortho-aminothiophenols are obtained in very good yields and with a high degree of purity. Oxydation to the disulfide compound is avoided by the processes of the invention.