Synthesis of D-glucono-1,4-lactones modified with linear saturated fatty acids and evaluation of their physical properties

To develop a novel low molecular–weight organogelator, D-glucono-1,4-lactones, in which all hydroxy groups were esterified with linear saturated fatty acids, were synthesized, and their gelation ability was evaluated. When a fatty acid was introduced, the six-membered ring D-glucono-1,5-lactone changed to a five-membered ring D-glucono-1,4-lactone, regardless of the length of the fatty acid. However, the gelation ability depended on the length of the fatty acid, and compounds esterified with palmitic acid (16 carbons) and stearic acid (18 carbons) showed a better gelation ability. Electron microscopy showed that the structure of the xerogels varied with the length of the fatty acids, with some forming a fiber structure and others forming plate-like crystals building up to a porous structure. In addition, their emulsification ability and crystal polymorphism were confirmed, and detailed polymorphic crystal analysis by FT-IR was performed to estimate the intermolecular packing structure at the molecular level.