Abstract: A process for separating ortho-, meta-, and/or para-dichlorobenzene from an isomeric mixture thereof which comprises:A. in a first step, distilling said isomeric mixture to distill over meta- and/or para-dichlorobenzene to leave behind ortho-dichlorobenzene which is separated off as bottoms product;B. in a second step, cooling the distillate from step A to a temperature of 10.degree. to 40.degree. C. whereby para-dichlorobenzene as a solid phase is obtained and separating said solid phase from liquid phase with which it is in admixture;C. in a third step, further cooling said liquid phase from step B to a temperature of -40.degree. to -5.degree. C. whereby to precipitate a second solid phase and separating said second solid phase from the liquid phase with which it is in admixture;D. in a fourth step, distilling the liquid phase from step C whereby to obtain an isomeric mixture as bottoms and an isomeric mixture as distillate; andE. removing m-dichlorobenzene from the distillate of step D.

Abstract: A process for the tertiary dealkylation of a tertiary alkyl containing m- and/or p-cresol wherein a tertiary alkyl containing m- and/or p-cresol is continously introduced into a reaction vessel with a small amount of sulfuric acid or an quivalent amount of a sulfonic acid and the reaction vessel contains a high concentration of m- and/or p-cresol or a high boiling phenol which under the prevailing reaction conditions is not substantially vaporized from the reaction mixture. The reaction mixture is maintained at a temperature of no greater than 230.degree. C. The reaction products are withdrawn continuously from the reactor (and separated into its components) and at the same time a small amount of the reaction mixture being withdrawn intermittently or continously from the reactor.

Abstract: Waste water resulting from the production of acrylonitrile by gas phase oxidation of propylene and ammonia with oxygen as washing water in the recovery section is purified by treating the waste water with 0.4 to 1 ton of steam per ton of waste water in a detoxification column attached to or following the separation column (for the separation of acetonitrile and acrylonitrile from the waste water in the acrylonitrile process) at a temperature from 100.degree. to 125.degree. C, at a pressure of 0 to 2 (gauge) atmospheres; separating the non-volatile resinous organic compounds from the thus treated waste water in an evaporator and using the vapors from the top of said evaporator to heat the said separation column and detoxification column; and optionally adding an organic amine to said distillation column or to said evaporator.