The use of sulfated tin oxide as solid superacid catalyst for heterogeneous transesterification of Jatropha curcas oil

摘要

This work presents the use of sulfated tin oxide enhanced with SiO2 (SO42-/SnO2-SiO2) as a superacid solid catalyst to produce methyl esters from Jatropha curcas oil. The study was conducted using the design of experiment (DoE), specifically a response surface methodology based on a three-variable central composite design (CCD) with alpha = 2. The reaction parameters in the parametric study were: reaction temperature (60 degrees C to 180 degrees C), reaction period (1 h to 3 h), and methanol to oil mole ratio (1 : 6 to 1 : 24). Production of the esters was conducted using an autoclave nitrogen pressurized reactor equipped with a thermocouple and a magnetic stirrer. The maximum methyl esters yield of 97 mass % was obtained at the reaction conditions: temperature of 180 degrees C, reaction period of 2 h, and methanol to oil mole ratio of 1 : 15. The catalyst amount and agitation speed were fixed to 3 mass % and 350-360 min(-1), respectively. Properties of the methyl esters obtained fell within the recommended biodiesel standards such as ASTM D6751 (ASTM, 2003).