Flash point of binary and ternary monoterpene mixtures: Experimental and modeling

Abstract

The flash point (FP) of pure or mixtures of flammable substances is an important indicator in designing fire risk mitigation and prevention measures in the chemical and oil industry. Although FP data of fuel constituents and blends are often found in the literature, studies addressing other flammable mixtures, such as essential oils (EOs) and their constituents (terpenes and terpenoids), are scarce. EOs are aromatic, volatile liquid mixtures extracted from plant matrices that present diverse biological properties and find numerous applications in the food, pharmaceutical, cosmetic, and fragrance industries. In this work, experimental FP measurements of binary and ternary mixtures of four structurally diverse monoterpenes (carvone, eucalyptol, limonene, and linalool), widely found in different EO profiles, were carried out. Besides, the Liaw-UNIFAC model and the COSMO-RS model were used to calculate the FP data of the studied mixtures, resulting in global root-mean-square deviations (RMSD) of 2.0 K and 0.7 K, respectively. Both models deliver better predictions than the ideal approach (RMSD = 2.4 K) for the studied systems, demonstrating the importance of considering nonideal effects when estimating the FP data of terpene mixtures. These results provide essential information for accurate process safety and fire risk assessment in the EO industry.