The sturcture and sorption properties of 5-hydroxy-6-methyluracil

The crystalline phase of 5-hydroxy-6-methyluracil isolated from aqueous solutions was studied by X-ray diffraction analysis. The elementary unit of the structure of 5-hydroxy-6-methyluracil was found to be the dimeric molecule. It was assumed that first dimers and then tetramers were formed in self-association, and subsequent self-assembly led to the association of tetramers. The resulting network structure contained alternating hydrophilic and hydrophobic cavities. The oxymethyluracil molecule was shown to have three bidentate "recognition" centers, two of which participated in tetramer formation and one, in the association of tetramers. The ability of 5-hydroxy-6-methyluracil to participate in hydrophilic and hydrophobic interactions was estimated by the method of reversed-phase gas chromatography for the example of the sorption of n-alkanes C6H14-C10H22 and n-alcohols CH3OH-C4H9OH. The dispersion properties of the surface of the adsorbent were found to depend on temperature and decrease as the temperature increased. Alcohols virtually did not form H-bonds with 5-hydroxy-6-methyluracil, and the increase in adsorption as the number of carbon atoms grew can be explained by the predominance of hydrophobic interaction between alcohol molecules and the surface of the adsorbent.