Mohammadreza Sabzimaleki - MSc graduated, biosystems engineering department, Tarbiat Modares University, Tehran
Barat Ghobadian - Associate professor, biosystems engineering department, Tarbiat Modares University, Tehran.
Masoud Dehghani Soufi - PhD Student, biosystems engineering department, Tarbiat Modares University, Tehran
Gholamhasan Najafi - Associate professor, biosystems engineering department, Tarbiat Modares University, Tehran.

The use of biodiesel to develop a higher added-value product is a very attractive solution for biodiesel production manufacturers in extending their production supply and the potential sales markets. Biolubricants are a new generation of lubricants, which are vegetable based, renewable and eco-friendly.In this study, biodiesel of castor oil was obtained and reacted with the Trimethylol propane (TMP), a polyhydric alcohol in order to produce biolubricant (TMP ester). Constant factors of the experiment include: reaction time and vacuum pressure and reaction temperature, catalyst concentration and molar ratio of methyl ester to TMP were considered as independent variables. The optimum values for this reaction were the methyl ester to TMP molar ratio of 4.78:1, reaction temperature of 139.93 œC, and catalyst concentration of 1.41%. The reaction efficiency was 96.128%, which was calculated from the results of NMR analyses. Physicochemical properties of the final product was comparable with those of the ISO VG68 reference lubricant standard.

biodiesel, biolubricant, castor, response surface methodology, optimization