Abstract

Background: Urea forms channel inclusion complexes with straight chain hydrocarbon, fatty acids, etc. The decomposition of urea is an interesting thermal induced solid state reaction yielding important by-products. Urea complexation with fatty acids has been successively used in the purification and separation of fatty acids, esters and alcohols.

Objective: To study the thermal gravimetry analysis behaviour for inclusion complexes of urea with stearic acid, palmitic acid and neem oil.

To compute specific heat capacity at constant pressure, as a function of temperature for the studied systems.

Method: The thermal gravimetry analysis and differential scanning calorimetry techniques are used.

Results: Thermal profiles of adduct of fatty acid with urea indicate shift in melting temperature of urea from 408 to 413 K. Thermal profiles of urea-neem oil adduct indicating that there is some incorporation of neem oil (inclusion compound formation) by lowering the melting temperature of urea.

Conclusion: The data of the corresponding weight loss and enthalpy changes for urea, fatty acids, neem oil, urea-fatty acids adduct and urea-neem oil adduct as a function of temperature are reported. The urea-fatty acid inclusion complexes show congruent behavior in melting, while for urea-neem oil inclusion complex an incongruent melting behavior is observed.

Keywords: Inclusion complex, specific heat capacity, thermal gravimetry analysis, urea decomposition, neem oil, fatty acids.

Graphical Abstract