PHYSICOCHEMICAL AND INFRARED SPECTRAL PROPERTIES OF BIODIESEL FUELS SYNTHESIZED FROM SOME VEGETABLE OILS

Abstract

A set of vegetable oils from Bolivian rain forests have been converted into biodiesel by base-catalyzed transesterification of fatty acids. Data regarding biodiesel properties dealing with feasibility of quality control procedures were obtained. Biodiesels have dynamic viscosity values in the range from 5.29 to 8.24 mPa.s at 20°C, and viscosity temperature dependences up to 90°C obey exponential functions. Dielectric constant values are between 3.75 and 4.34, whereas for diesel fuel is 2.35 ± 0.25. Measured diesel fuel density is 0.857 ± 0.015 g/cm³ at 20°C, while biodiesel densities are about 0.879 g/cm³. Temperature dependent specific gravity changes gave linear behavior between 20°C and 80°C. Heats of combustion values expressed in kJ/g are in the range 46.37 - 55.56 and a value of 49.42±2.20 for diesel fuel as reference. Measured differences do not depend on oils composition and could be attributed to the synthesis procedure. Neither water nor glycerol effects has been detected as meaningful impurities. Biodiesel-diesel fuel standard mixtures gave straight lines as calibration procedure to quantify biodiesel by infrared spectroscopy

A set of vegetable oils from Bolivian rain forests have been converted into biodiesel by base-catalyzed transesterification of fatty acids. Data regarding biodiesel properties dealing with feasibility of quality control procedures were obtained. Biodiesels have dynamic viscosity values in the range from 5.29 to 8.24 mPa.s at 20°C, and viscosity temperature dependences up to 90°C obey exponential functions. Dielectric constant values are between 3.75 and 4.34, whereas for diesel fuel is 2.35 ± 0.25. Measured diesel fuel density is 0.857 ± 0.015 g/cm³ at 20°C, while biodiesel densities are about 0.879 g/cm³. Temperature dependent specific gravity changes gave linear behavior between 20°C and 80°C. Heats of combustion values expressed in kJ/g are in the range 46.37 - 55.56 and a value of 49.42±2.20 for diesel fuel as reference. Measured differences do not depend on oils composition and could be attributed to the synthesis procedure. Neither water nor glycerol effects has been detected as meaningful impurities. Biodiesel-diesel fuel standard mixtures gave straight lines as calibration procedure to quantify biodiesel by infrared spectroscopy