DISCOTIC COLUMNAR LIQUID-CRYSTALS IN OLIGOSACCHARIDE DERIVATIVES .3. ANOMERIC EFFECTS ON THE THERMO-MESOMORPHIC PROPERTIES OF CELLOBIOSE OCTA-ALKANOATES

The alpha- and beta-anomers of cellobiose octa-alkanoates with purities higher than about 95 per cent were prepared from beta-cellobiose by two simple esterification methods. The carbon number n of the acyl substituents ranged from 7 to 10 in both anomers. Both alpha- and beta-anomers exhibited two types of discotic columnar phases (D-ho and D-ro), depending on n and temperature, but their phase diagrams were appreciably different. Generally, the alpha-anomers formed more stable mesophases than the beta-anomers, in the D-ro phase of the beta-anomers, the column axis was tilted from the normal to the 'disks', while no such tilting was observed in the other phases.