Abstract
The vaporization enthalpy of benzocaine, ethyl 4-aminobenzoate, has been evaluated using correlation gas chromatography at 298.15 K. The temperature dependence of retention time has also been used to evaluate the vapor pressure of the sub-cooled liquid from 298.15 K to the fusion temperature, 365.2 K, by correlation with the vapor pressures of the compounds used as standards. The vaporization enthalpy calculated from the vapor pressures of benzocaine at the melting point was combined with the experimental fusion enthalpy to evaluate the sublimation enthalpy at the fusion temperature. Application of the Clausius–Clapeyron equation together with the vapor pressure common to both phases permitted calculation of the vapor pressure of the solid at 298.15 K. Similar calculations were performed for two of the standards that were solids for comparisons with experimental data. Vaporization and sublimation enthalpies of (91.8 ± 4.2) and (112.9 ± 4.3) kJ mol−1 are calculated for benzocaine at 298.15 K as are vapor pressures of 0.0083 and 0.0018 Pa for the sub-cooled liquid and crystalline material, respectively.
Similar content being viewed by others
References
http://www.drugs.com/mtm/benzocaine-topical.html#WEUD2iR4dlAjjjuA.99. Accessed 07 Feb 2013
http://www.fda.gov/Drugs/DrugSafety/ucm250024.htm. Accessed 07 Feb 2013
Almeida ARRP, Monte MJS (2012) J Chem Thermodyn 53:100
Lipkind D, Chickos JS (2010) J Chem Eng Data 55:698
Umnahanant P, Chickos J (2012) J Pharm Sci 101:2045
Peacock LA, Fuchs R (1977) J Am Chem Soc 99:5524
Wassvik CM, Holmen AG, Draheim R, Artursson P, Bergstrom CAS (2008) J Med Chem 51:3035
Acree W Jr, Chickos JS (2010) J Phys Chem Ref Data 39:1
Chickos JS, Hesse DG, Liebman JF (1993) Struct Chem 4:261
Wilson JA, Chickos JS (2013) J Chem Eng Data 58:322
Chickos JS (2010) J Chem Eng Data 55:1558
Author information
Authors and Affiliations
Corresponding author
Additional information
This paper is dedicated to Maria Victoria Roux, calorimetrist and colleague, physical chemist and friend.
Electronic supplementary material
Below is the link to the electronic supplementary material.
Rights and permissions
About this article
Cite this article
Gobble, C., Gutterman, A. & Chickos, J.S. Some thermodynamic properties of benzocaine. Struct Chem 24, 1903–1907 (2013). https://doi.org/10.1007/s11224-013-0262-9
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s11224-013-0262-9