Evaluation of vapor pressures of 5-Methylresorcinol derivatives by thermogravimetric analysis

• Accuracies of literature vapor pressures calculated from TGA data are discussed.
• Vapor pressures for different 5-methylresorcinol derivatives were determined.
• The error of the measured vapor pressure data is estimated to be below 13.5%.
• TGA may be superior to group contribution methods for vapor pressure estimation.

The present study was carried out to evaluate the vapor pressures of various 5-methylresorcinol derivatives using a thermogravimetric analyzer (TGA). In the experiments, 9–12 mg of each 5-methylresorcinol ether or ester was used, which allowed vapor pressures up to 24,500 Pa (on average) to be determined. The error in the measured vapor pressure values is estimated to be below 13.5% at vapor pressures lower than 10,000 Pa, while at values between 10,000 and 24,500 Pa it is below approximately 12%.The quality of the vapor pressure data was evaluated with anthracene, benzoic acid, docosane, hexadecane, nonane, and resorcinol as standard compounds using different calculation methods. The results showed that vapor pressures calculated by the mass transfer equation combined with estimated binary diffusion coefficients gave the most consistent results for these compounds, with errors always smaller than 15% (average absolute deviation 6.4%). These results are also consistent with the accuracies reported in literature for non-isothermal TGA. Therefore, this method could be used for evaluation of preliminary vapor pressure data as it may give more accurate results than group contribution methods.