Enthalpy of vaporization

The analysis of the enthalpy of vaporization makes it possible to determine the quantity of thermal energy required to transform a substance from the liquid state to the gaseous state , at constant pressure.
This thermodynamic quantity is essential for understanding the thermal and energetic behavior of volatile liquids, solvents, aromatic extracts or even complex mixtures used in industrial formulations.

The study of the enthalpy of vaporization is carried out by differential scanning calorimetry (DSC) or by indirect methods based on the measurement of the saturated vapor pressure. It makes it possible to obtain information on intermolecular bonds , the purity of compounds , or even the volatility of mixtures .

Experimental methods and protocols

Differential scanning calorimetry (DSC) is the reference method for measuring the energy absorbed during a change of state.
The principle is based on the comparison between:

• a sample containing the substance under study,
• and an inert reference .

When vaporization occurs, the difference in heat flow between the two is recorded, allowing the enthalpy to be calculated in joules per gram (J/g) or kilojoules per mole (kJ/mol).

Depending on the nature of the product, other approaches can be used:

• Thermogravimetric analysis (TGA / TGA) to observe the mass loss associated with vaporization,
• Vapor pressure measurement for organic solvents,
• Thermodynamic modeling from experimental data for complex mixtures.

Dies and industrial applications

Vaporization enthalpy analysis is used in many sectors:

• Cosmetics industry : assessment of the volatility of perfumes, essential oils and solvents used in formulas.
• Food and nutraceuticals : characterization of volatile compounds in plant extracts, flavorings or edible oils.
• Polymer packaging and materials : control of residual solvents and evaluation of the thermal stability of polymers.
• Environment and chemistry : study of the volatility of organic pollutants (VOCs, chlorinated solvents, hydrocarbons).
• Energy and processes : calculation of the energy balance in evaporation, distillation or drying processes.

Related analyses

To complete this thermal characterization, YesWeLab recommends coupling this study with:

• Thermogravimetry (ATG/TGA) to monitor mass loss associated with vaporization,
• Measurement of water vapor and gas permeability to link thermal and barrier properties of packaging.

Interpretation of results

The obtained values ​​of vaporization enthalpy allow:

• Compare the volatility of different substances,
• Determine the purity of a compound (deviation from the theoretical value),
• Optimize thermal processes (distillation, drying, encapsulation),
• Monitor the stability and safety of products containing volatile solvents.

liquid-vapor equilibrium models for the formulation of complex mixtures.

YesWeLab expertise

YesWeLab relies on a network of ISO 17025 and COFRAC accredited laboratories , specializing in thermal and calorimetric analyses .

Thanks to the YesWeLab digital platform , you can:

• Order your thermal analyses online,
• Track your samples in real time,
• Access your results in a clear and usable format for your technical and regulatory reports.