ISSN: 2449 - 0539 BAYERO JOURNAL OF ENGINEERING AND TECHNOLOGY (BJET) VOL.11 NO.2, AUGUST, 2016 Available online at www.bayerojet.com 20 MODELLING OF BINARY SOLVENT EXTRACTION OF CLOVE (SYZYGIUM AROMATICUM) OIL USING RESPONSE SURFACE METHODOLOGY Galadima, M.S. and Muhammad, A. Department of Chemical Engineering Ahmadu Bello University, Zaria, Nigeria Email: galadimams@yahoo.com ABSTRACT Modelling and optimization of oil yield in binary solvent extraction of clove oil using response surface methodology (RSM) were carried out in this study. The effects of two factors: extraction time and sol- vent/solvent ratio on the oil yield were investigated. A total of 13 experimental runs were generated using central composite design (CCD) in the Design Expert 6.0.6 version. A quadratic model was obtained to predict the oil yield and the Analysis of Variance (ANOVA) showed that the model was significant with P-value <0.0001and R 2 value of 0.9962. The statistical model predicted the optimum oil yield to be 30.264% at the optimal condition of time 120 minutes and hexane/ethanol ratio of 1.00. GC-MS analyses of the oil indicated that the main components were eugenol acetate (46.82%), 16-octadecenoic acid methyl ester (16.46%), Hexadecanoic acid methyl ester (7.71%), 1,6,9-Tetradecatriene (6.14%) and stearic acid (3.66%). Physico-chemical properties of the oil indicated that acid value was 23.01 while the iodine value was 20.05 g I 2 /100 g oil. The oil was dark brown in colour with a pungent clove smell. Keywords: Syzygium Aromaticum; Solvent Extraction; RSM; Modelling; Central Composite Design. 1.0 INTRODUCTION Clove (Syzygium Aromaticum) is widely cultivated in Madagascar, Sri Lanka, Indonesia and the south of China as reported by Guan et al. (2007). The clove tree is a perennial tropical plant which grows to a height ranging from 10 to 20 m, having large oval leaves and crimson flowers in numerous groups of terminal clus- ters. Two major products are available and marketed from clove tree: the clove which is the unopened green fully-grown buds, upon drying, and the essential oil extracted either from bud, leaf or stem. Clove is a well-known spice that has been highly studied because of therapeutic activities of its essential oil (Scopel et al., 2013). The oils of the clove have been known to stim- ulate and disinfect a body as it travels through the body. Clove can be used to promote the flow of saliva and gastric juices (Bhowmik et al., 2012). Several methods exist for the recovery of volatile oils from plant materials such as hydrodiatillation, solvent extraction and supercritical fluid extraction. Yazdani et al. (2005) as well as Guan et al. (2007) carried out comparative studies of three methods of clove oil extraction. Hadiyanto et al. (2014) used adsorption distillation process to improve the clove oil quality. There are several works on modeling of volatile oils extraction but most of them are on supercriti cal fluid extraction. Martinez et al. (2007) developed a kinetic model to predict clove oil extraction on a large scale in supercritical fluid extraction (SFE). Hatami et al. (2010) carried out mathematical modeling and ge- netic algorithm for clove oil extraction. Ogunleye and Eletta (2012) modeled solvent extraction of Jatropha curcas seed oil. Scopel et al. (2013) also developed a thermodynamic model for SFE.