Browsing by Author "Dias, Rafael M."
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- Deterpenation of citrus essential oil via extractive distillation using imidazolium-based ionic liquids as entrainersPublication . Vilas-Boas, Miguel; Batista, Fábio R.M.; Dias, Rafael M.; Coutinho, João A.P.; Ferreira, Olga; Costa, Mariana C.; Pinho, SimãoThe deterpenation of citrus essential oils (CEO) is crucial in many industries to promote the stability and preserve the organoleptic properties of the final product, improving considerably the oxygenated fraction purity. Methods: Two imidazolium ionic liquids (ILs), [C4mim][OAc] and [C4mim]Cl, were applied as novel separation agents in a deterpenation process constituted by an extractive distillation column and a flash separator unit, aiming to remove hydrocarbon terpenes from the essential oil. The CEO was modeled as a mixture of the commonly found limonene (monoterpene) and linalool (monoterpenoid). To support the process simulation, isobaric vapor-liquid equilibrium measurements were conducted for the binary limonene/linalool and ternary limonene/linalool/IL mixtures at 5 kPa, and the data were successfully correlated with the NRTL model. Significant findings: The simulation results demonstrate that [C4mim]Cl improved the purity of linalool in the final product. Moreover, both [C4mim]Cl and [C4mim][OAc] reduced the required stages in the distillation column to obtain a terpeneless CEO with a certain purity, [C4mim]Cl being the most effective option.
- Flash point of binary and ternary monoterpene mixtures: experimental and modelingPublication . Vilas-Boas, Sérgio M.; Nascimento, Debora C. do; Dias, Rafael M.; Rozo, Gabriel H.; Neto, Antonio M.B.; Ferreira, Olga; Pinho, Simão; Costa, Mariana C.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.