PHYSICOCHEMICAL STUDIES OF SYSTEMS AND PROCESSES Dissolving and Selective Properties of Morpholine-based Mixed Solvents

Liquid liquid phase equilibria were studied in the systems morpholine monoethanolamine hexane benzene, morpholine mono(ethylene glycol) hexane benzene, morpholine monoethanolamine hep- tane toluene, and morpholine mono(ethylene glycol) heptane toluene at 40, 50, and 60 C. A mathematical description of the phase equilibria in the systems studied was obtained. A number of requirements, the most important among which are selectivity and dissolving ability, are imposed upon extracting agents used to recover individual aromatic hydrocarbons from reforming cat- alyzates by liquid extraction techniques. Various sol- vents have acquired industrial importance (1 4); how- ever, no solvent has been found up to now, satisfy- ing all the requirements. The main extracting agents used in domestic industry still are tri(ethylene glycol) (TEG) and di(ethylene glycol) (DEG) possessing low selectivity and dissolving ability. In this connection, extraction is commonly performed at a temperature of 150 C and high solvent to raw material mass ratio ((8 15) : 1), which leads to high operation costs. The most promising way to solve this problem is to pass to use of extracting agents of mixed type, whose ap- plication will improve the performance characteristics in manufacture of monocyclic aromatic hydrocarbons. This study is concerned with phase equilibria in liquid liquid systems formed from hexane benzene and heptane toluene model mixtures and morpholine- based binary solvents of varied composition.