Separations via Chromatographic Columns and Crystallization

Relatively few molecular separations have been studied from the utilitarian standpoint. One of these, the purification of fullerenes via 8 , is discussed on p. 170. In a reciprocal experiment the separation of 4 , 6 , and 8 with a column using a chemically-bonded C o silica stationary phase has been re-ported. Chromatographic selectivity has been achieved for amino acid esters and alkali metal cations on silica-bonded calix[4]arene tetraesters, the structure of which has been explored by and Si-CP-MAS NMR. Silica-bonded calixarenes have also been used as packing materials for HPLC columns that are capable of separating disubstituted aromatics, peptides, and nucleosides. The HPLC separation of phenols using 6 ° as a constituent of the eluent has been described.  

Xylenes have been separated by extractive crystallization using 4 -P, 8oo the removal of trihalomethanes from chlorinated water with 6 has been reported.  

Casnati, A. Contino, A. Mirone, L. Sciotto, D. Ungaro, R. J. Chem. Soc., Chem. 

Vicens, J. Armah, A. E. Fujii, S. Tomita, K.-I. J. Inclusion Phenom. Mol. Recognit. Chem. 1991, 

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