Thermodynamics Research Center / ThermoML | Journal of Chemical and Engineering Data

ABSTRACT

The critical temperatures and pressures of phenylalkanoic acids with a straight alkyl chain C6H5(CH2)nCOOH (n= 1 to 6) have been measured. The method of pulse heating of a wire probe placed into the substance under study has been used. The method minimizes the thermal decomposition because residence times are from (0.035 to 1) ms. An equation for the correlation of the critical pressures of phenylalkanoic acids with the number of CH2 groups between phenyl and carboxyl functional groups and molar mass has been obtained. The experimental critical constants of phenylalkanoic acids have been compared with the values calculated by the group-contribution methods of Constantinou and Gani and Marrero and Gani.