Desterpenação de óleo essencial utilizando líquidos iônicos.

Abstract

It is estimated that 3000 essential oils are known, of which 300 are commercially attractive. Most essential oils are destined for the aroma and fragrance market. Citrus oils are among the most widely used in different industrial branches; however, due to the large amount of terpene compounds and their chemical instability, a terpene removal process, called deterpenation, needs to be employed to preserve the organoleptic characteristics of the oil. Therefore, the main objective of the present study is to investigate the deterpenation of citrus essential oils using ionic liquids ([C2mim][OAc] and [C4mim][OAc]) as solvents. To achieve this, it was necessary to experimentally determine ELV data at 5 kPa using a Fischer distiller and thermodynamic modeling considering the NRTL and UNIQUAC equations.Various unit operations for deterpenation were simulated in Aspen Plus, including extraction, simple distillation, and extractive distillation, using a model orange oil feed stream (limonene and linalool). In liquid-liquid extraction, using ionic liquids, deterpenation reached only 70% purity. Simple distillation under atmospheric pressure proved unfeasible, but vacuum distillation required many stages and high energy consumption to achieve purities of 99%. Extractive distillation with ionic liquids was the most promising, successfully altering the volatility of the components. With 15 trays and a reflux ratio of 1.0, pure linalool was obtained with 25 kg/h of solvent. Increasing to 100 kg/h of solvent, only 10 trays and a reflux ratio of 0.5 were required. However, the recovery of the ionic liquid was challenging, so an alternative configuration was investigated: extractive distillation with a stripping column. The results were competitive, being advantageous for high purities and high solvent flow rates, although it required more energy. Ionic liquids stood out as solvents due to favorable interactions, driven by the hydrogen bond-accepting character of the anion. In conclusion, the study plays a crucial role in the area of essential oils, highlighting the effectiveness of ionic liquids in deterpenation via extractive distillation.