Separation of Xylene Isomers by Adductive Crystallization with Nickel Complex

Characteristics of p-xylene clathrate

Abstract

Tetra- (4-methylpyridino) nickel dithiocyanate was used as metal complex to make a clathrate with p-xylene.
The solubility of nickel complex in methylcellosolve solution was found to be largely influenced by dissociation. Thus the suppressive effect of 4-methylpyridine on the dissociation was studied.
p-xylene clathrate was formed using batch cooling crystallization in methylcellosolve solution containing p-xylene, nickel complex and 10 Vol % 4-methylpyridine. It was found that clathrate composition and p-xylene yield obtained by adductive crystallization are remarkably dependent on initial solution composition.
Furthermore, clathrate was formed by reaction between nickel complex powder and p-xylene, when solid-liquid equilibrium measurements were carried out to investigate the structure of clathrate in solid phase.