Boiling points of the propylene glycol + glycerol system at 1 atmosphere pressure: 188.6–292 °C without and with added water or nicotine

Introduction:
This text reports a study on the boiling points of the propylene glycol (PG) and glycerol (GL) system, commonly used in electronic cigarettes (e-cigarettes) or electronic nicotine delivery systems (ENDS), with added water or nicotine. The study aims to provide a better understanding of the boiling point (BP) characteristics of the PG + GL system, which is crucial for the design and safe use of e-cigarettes.

Key Points:

* The study measures the BPs of PG + GL mixtures over the full binary composition range at 1 atmosphere pressure, using the Gibbs–Konovalov theorem to provide BP as a function of composition by mole-percent, weight-percent, and volume-percent.
* The effect of added water (2.5 and 5 mol%) and nicotine (3 mol%) on the BPs of PG + GL mixtures is also investigated.
* Water is found to decrease the BPs of PG + GL mixtures significantly at all compositions tested, while nicotine decreases the BPs of PG + GL mixtures containing ~75 GL: 25 PG (by moles) or more.
* The study finds that added water (5, 10, and 15 mol%) has no significant impact on solvent (PG or GL) degradation for the particular device used.
* The research also examines the effect of added water on electronic cigarette degradation production, specifically on the formation of certain aldehydes and formaldehyde hemiacetals.

Main Message:
The study provides valuable information on the BPs of PG + GL mixtures, which is critical for the safe and efficient design of e-cigarettes. The findings indicate that water and nicotine can significantly affect the BPs of PG + GL mixtures, with water having a more pronounced impact. The results also suggest that added water does not contribute to solvent degradation in e-cigarettes. Overall, this research contributes to a better understanding of the BP characteristics of the PG + GL system, which can help improve the safety and performance of e-cigarettes.

Duell, anna K., James F. Pankow, Samantha M. Gillette, and David h. Peyton. “Boiling Points of the Propylene Glycol + Glycerol System at 1 atmosphere Pressure: 188.6–292 °C without and with added Water or Nicotine.” Chemical Engineering Communications 205, no. 12 (December 2, 2018): 1691–1700. https://doi.org/10.1080/00986445.2018.1468758.