Preparation and properties of biodiesel from Cynara cardunculus L. oil

A study was made of the reaction of transesterification of Cynara carduncul us L. oil by means of methanol, using sodium hydroxide, potassium hydroxide , and sodium methoxide as catalysts. The objective of the work was to chara cterize the methyl esters for use as biodiesels in internal combustion moto rs. The operation variables used were methanol concentration (5-21 wt %), c atalyst concentration (0.1-1 wt %), and temperature (25-60 degrees C). The evolution of the process was followed by gas chromatography, determining th e concentration of the methyl esters at different reaction times. The biodi esel was characterized by determining its density, viscosity, high heating value, cetane index, cloud and pour points, Ramsbottom carbon residue, char acteristics of distillation, and flash and combustion points according to I SO norms. The biodiesel with the best properties was obtained using 15% met hanol, sodium methoxide as catalyst (1%), and 60 degrees C temperature. Thi s biodiesel has very similar properties to those of diesel no. 2.