Werku, Teshome (Ass.Professor)Kidane, Meaza2018-07-162023-11-102018-07-162023-11-102016-06http://etd.aau.edu.et/handle/12345678/8569The overall objective of this study was the extraction and characterization of the essential oil from the leaves of Eucalyptus globulus. Eucalyptus globulus of Myrtaceae family was the raw material of the experimental research which was collected from Entoto forest, 15 Km North West (NW) of Adiss Ababa. First, the leaf of Eucalyptus globulus was dried through partial sun drying. Then the dried Eucalyptus leaves were crushed in cross beater mill with sieve size of 10 mm and by cutting mill. The sample was sieved using a set of sieves sizes. Next to this, the experimental work was carried out by steam distillation set up. A general factorial design was employed to the extraction process using DESIGN EXPERT 7.0 software and linear regression model. This design helped to identify individual effects of extraction time, and particle size, as parameter and their interaction in the entire extraction process. In the extraction experiment, the minimum oil yield of 0.05% was obtained after the extraction time of 1 hour with particle size ranges of 12.5-20 mm and maximum oil yield of 1.19 % was obtained at optimum extraction time of 3 hours with particle size ranges of 5-8 mm. This shows that, increasing extraction time (optimum of 3hrs) and decreasing particle size increases yield. Characterization of the oil was also carried out. Accordingly the yield was found with 1.4463 refractive index value, 0.90841 specific gravity, and optical rotation, 6.31 pH, 3.15 mpas dynamic viscosity, 174 boiling, 31.725ml/g iodine value, 14 ml/g saponification value, 19.635 acid value and 1,8 cineol(99%) component were obtained. Finally, the findings of this study will help to indicate the quality of the Eucalyptus oil which is important in the production of high value essential oils. Key Words: Eucalyptus Globules, Steam distillation, Eucalyptus oil, Gc-Ms, 1, 8 Cineol Addis Ababa, EntotoenEucalyptus Globules, Steam distillation, Eucalyptus oil, Gc-Ms, 1, 8 Cineol Addis Ababa, EntotoThesis