Entropy and Related Thermodynamic Properties of Acetonitrile (Methyl Cyanide)

The heat capacity, the heats of fusion and vaporization, and the entropy have been measured for acetonitrile. This substance has a triple point at 229.315±0.020°K (ΔH=1951.96±0.40 cal/mole), a broad transition at 216.9±0.1°K (ΔH=214.6±0.3 cal/mole), and a heat vaporization at 298.15°K of 7941 cal/mole. The standard entropy of the ideal gas at 25°C was found to be 58.67±0.20 cal/deg·mole. The best value of the entropy calculated from statistical mechanics, 58.01 cal/deg·mole, shows a surprisingly large discrepancy from our experimental results.

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