Order–disorder phenomena. Part 2.—Order–disorder phase equilibria in D- and L-systems of camphor and related compounds

Abstract

The phase diagrams of D- and L- systems of camphor and camphor oxime have been redetermined. The phase diagram of D- and L-camphoric anhydride has been determined for the first time. An important point was the absence of eutectic behaviour in the phase diagram of camphor as determined by earlier measurements. Attention was mainly focused on the solid-state orientational transitions which exhibit λ-transition characteristics. The estimated critical temperature of mixing of DL-camphor (59 K) lies below the orientational transition temperature (205 K) and so accounts for the lack of eutectic behaviour in this system. It is shown that the camphor phase diagram is of type VI according to the scheme of classification presented in part 1 of this series. Finally the phase diagrams of camphoric anhydride and camphor oxime are discussed. Although the three phase diagrams are similar, there are gross differences in the fundamentals involved.