Synthesis of biodiesel by KOH-catalyzed methanolysis of flaxseed oil and determination of fuel properties

Abstract

Vegetable oils are usually not used directly in diesel engines due to their high viscosity. In this study, biodiesel was produced from flaxseed oil by transesterification at 60 °C. The process variables – methanol concentration (as methanol:oil molar ratio), catalyst concentration (KOH % wt/wt of oil) and reaction time – were used to analyze the process on the basis of methyl ester yield and kinematic viscosity. The reaction with catalyst concentration 1%, reaction time 45 minutes and methanol:oil molar ratio 6:1 had the highest methyl ester yield, of 94%. The kinematic viscosity decreased from 24.2 to 3.54 cSt following the reaction, producing a suitable value within the standard limits. Fuel properties of the flaxseed methyl ester, such as American Petroleum Institute (API) gravity, flash point, calorific value, acid number and carbon residue, were measured and found to be within the standard limits.

Keywords:

• Linseed oil
• transesterification
• fuel characterization
• vegetable oil
• biofuel
• methyl ester yield

Disclosure statement

No potential conflict of interest was reported by the authors.