Heat Capacities and Derived Thermodynamic Functions of 1-Propanol between 10 K and 350 K and of 1-Pentanol between 85 K and 370 K

Abstract

Molar heat capacities of 1-propanol were measured from 10 K to 350 K, and Sabs,m(T) and Hm(T)−Hm(0) were calculated. The enthalpy of fusion was found to be (5400 ± 10) J·mol-1; the triple-point temperature was calculated as (148.71 ± 0.02) K. Similar measurements were made on 1-pentanol between 85 K and 370 K; the enthalpy of fusion was found to be (10510 ± 20) J·mol-1; the triple-point temperature was (195.6 ± 0.1) K. The molar heat capacity of the liquid 1-alcohols with a number of carbon atoms n in the linear chain between 3 and 22 can be described by Cp,l(n,T) = {99.38 + 17.769n + 0.05199n(T/K) − 0.8742(T/K) + 1265.2/(T/K) + 0.0022603(T/K)2} J·K-1·mol-1, with a standard deviation of 3.1 J·K-1·mol-1. The main deviations occur above 370 K, where the experimental data start to flatten. Plotting the experimental heat capacity data for the 1-alcohols with a carbon number in the chain between 3 and 22 on a mass basis showed that all curves pass through almost the same value around 290 K.