title: Kinetic and Thermodynamics studies for Castor Oil Extraction Using Subcritical Water Technology.
abstract: In this work both kinetic and thermodynamics of castor oil extraction from its seeds using subcritical water technique were studied. It was found that the extraction process followed two consecutive steps. In these steps, the oil was firstly extracted from inside the powder by diffusion mechanism. Then the extracted oil, due to extending the extraction time under high temperature and pressure, was subjected to a decomposition reaction following first order mechanism. The experimental data correlated well with the irreversible consecutive unimolecular-type first order mechanism. The values of both oil extraction rate constants and decomposition rate constants were calculated through non-linear fitting using DataFit software. The extraction rate constants were found to be 0.0019, 0.024, 0.098, 0.1 and 0.117 min(-1), while the decomposition rate constants were 0.057, 0.059, 0.014, 0.019 and 0.17 min(-1) at extraction temperatures of 240, 250, 260, 270 and 280°C, respectively. The thermodynamic properties of the oil extraction process were investigated using Arrhenius equation. The values of the activation energy, Ea, and the frequency factor, A, were 73 kJ mol(-1) and 946, 002 min(-1), respectively. The physicochemical properties of the extracted castor oil including the specific gravity, viscosity, acid value, pH value and calorific value were found to be 0.947, 7.487, 1.094 mg KOH/g, 6.1, and 41.5 MJ/Kg, respectively. Gas chromatography analysis showed that ricinoleic acid (83.6%) appears as the predominant fatty acid in the extracted oil followed by oleic acid (5.5%) and linoleic acid (2.3%).
authors.affiliation: Department of Chemical Engineering, El-Minia University.
authors.forename: Wael
authors.initials: W
authors.lastname: Abdelmoez
authors.forename: Eman
authors.initials: E
authors.lastname: Ashour
authors.forename: Shahenaz M
authors.initials: SM
authors.lastname: Naguib
authors.forename: Amr
authors.initials: A
authors.lastname: Hilal
authors.forename: Dalia A
authors.initials: DA
authors.lastname: Al Mahdy
authors.forename: Engy A
authors.initials: EA
authors.lastname: Mahrous
authors.forename: Essam
authors.initials: E
authors.lastname: Abdel-Sattar
mesh_terms: D002368:Castor Oil / Q000737:chemistry / Q000302:isolation & purification*; D002849:Chromatography, Gas; D004058:Diffusion; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D011312:Pressure; D012639:Seeds / Q000737:chemistry; D013816:Thermodynamics; D014783:Viscosity; D014867:Water / Q000737:chemistry*
chemical_list: D014867:Water; D002368:Castor Oil