Synthesis and Physical Properties of Normal Higher Primary Alcohols. IV. Thermal and X-Ray Studies on the Polymorphism of the Alcohols of Even Carbon Numbers from Dodecanol to Tetratriacontanol

Abstract 1. Determination of the melting points and transition points of the even carbon numbered alcohols from C12 to C34 was made by thermal analysis. The transition points of the alcohols above C18, except C22, have never been reported. 2. The reversible transition sets in at C14 and terminates at C26. The transition of C28 and C32 is irreversible, appearing only on cooling and both transitions disappear at C34. Probably the pure sample of dodecanol may indicate no transition in any methods of measurements. 3. Properties of the a forms gradually change with increasing chain lengths. 4. The β to γ and α to γ transformations were examined by X-ray pattern measurements and the results were discussed. 5. Transition points and X-ray spacings may be reliable criteria of purity of higher alcohols, and probably of some other long chain compounds.