A SIMPLE THERMODYNAMIC ANALYSIS OF SOLID-SOLUTION FORMATION IN BINARY-SYSTEMS OF HOMOLOGOUS EXTENDED-CHAIN ALKANES

Binary mixtures of n-alkane chains of comparable length are treated within the Bragg-Williams approximation. A simple model is developed to explain which pairs will form a continuous series of solid solutions (close to their respective melting points). Results are fit very well by the empirical rule that c//t less than equivalent to 1. 22 c//s ensures such a continuous, mutual solubility. Here, c//t is the number of carbon atoms in the longer alkane and c//s the smaller number. Close analogies are found to the well known Hume-Rothery and Vegard's Law generalizations for metallic systems.