The Cross-Chain Configuration and a New Type of Phase Transformation in Solid Long Chain Acid Amides

From the X-ray investigation on the single crystal of long chain acid amides of even carbon number from C=10 to 18, three phases are found to exist. Phase A in palmitic, myristic, and capric acid amides has the unusual crossed chain configuration similar to that found in potassium soaps. In phase B, found in palmitic and stearic acid amides, and phase C, in stearamide under a special condition, chains are parallel as in the ordinary long chain compounds. All phases seem to be stable at room temperature, but phase A of palmitic amide transforms irreversibly into phase B by heating. But the basal plane is almost unchanged during the transformation.