Abstract: In a process for separating a mixture comprising cyclohexanone and phenol, at least a portion of the mixture is distilled in the presence of a solvent including at least two alcoholic hydroxyl groups attached to non-adjacent saturated carbon atoms, water, and in the presence or absence of a hemiketal defined by the formula (I) or the formula (II): wherein R1, the same or different at each occurrence, is independently an alkylene group having from 2 to 10 carbon atoms, R2 is an alkylene group having from 4 to 10 carbon atoms and/or R3 is hydrogen or the following group: and in the presence or absence of an enol-ether derived from the hemiketal defined by the formula (I) or the formula (II), wherein the total concentration of the hemiketal and enol-ether, expressed in term of weight percentage of the total weight of the feed to the distilling step, is at most 0.01%.

Abstract: A method is provided for treating the effluent from a hydrocarbon pyrolysis unit processing heavier than naphtha feeds to recover heat and remove tar therefrom. The method comprises passing the gaseous effluent to at least one primary transfer line heat exchanger, thereby cooling the gaseous effluent and generating superheated steam. Thereafter, the gaseous effluent is passed through at least one secondary transfer line heat exchanger having a heat exchange surface with a liquid coating on said surface, thereby further cooling the remainder of the gaseous effluent to a temperature at which tar, formed by the pyrolysis process, condenses. The condensed tar is then removed from the gaseous effluent in at least one knock-out drum. An apparatus for carrying out the method is also provided.