SYNTHESIS AND CHARACTERIZATION OF TRIMETHYLOLPROPANE-BASED BIOLUBRICANTS FROM CASTOR OIL

Abstract

This paper presents the synthesis and characterization of Trimethylolpropane (TMP) based biolubricant from castor oil seed. Castor Oil Methyl Ester (COME) was synthesized at a temperature of 60 o C, reaction time of 1 hour, molar ratio of oil to methanol of 1:250 and 1 % wt/wt catalyst via (in situ transesterification) reactive extraction. The TMP ester (Biolubricant) from castor oil was further subsequently synthesized at a temperature of 120 o C, reaction time of 1 hour, molar ratio of COME to trimethylolpropane (TMP) of 4:1 and catalyst concentration of 0.8 wt%. The TMP ester of castor oil was characterized for its flash point, pour point, viscosity at 40 o C and at 100 0 C and viscosity index. Fourier Transform Infra-Red (FT-IR) and Gas Chromatography-Mass Spectrophotometer (GC-MS) analysis were carried out on the Biolubricant to confirm the presence of ester group and the composition of the synthesized lubricant. The COME yield was 98.42wt% based on the weight of the oil seed. The transesterification of in situ derived COME with TMP yielded 96.56 wt% of the TMP ester (Biolubricant). The characterization of biolubricant shows favourable lubricating characteristics. The presence of ester group in the resulting biolubricant was confirmed by FT-IR analysis and the percentage of the composition of biolubricant determined by GC-MS analysis revealed a fatty acid composition of 2.88 %, monoester of 0.63 %, diester of 1.70 % and triester (desired end product) of 94.79 %. These FT-IR and GC-MS analysis result shows the effectiveness of the chemical modification of castor oil to biolubricant. The result of characterization of the biolubricant compares favourably with the ISO VG thereby establishing the potential of the biolubricant as gear oil.