Abstract:
Partially dehydrated castor oil (PDCO) which is of less use in the paint and furniture coating formulations has been modified to develop biolubricant base stocks. PDCO (44.1%, non-conjugated linoleic acid; 32%, conjugated linoleic acid (18:2) isomers and 15.3% ricinoleic acid) obtained from a local industry was hydrolyzed under alkaline conditions. The fatty acids obtained (PDCFAs) in 98% yields were reacted with polyols namely 2-ethyl hexanol, neopentyl glycol, trimethylol propyl, pentaerythritol to obtain respective isoalkyl erters and esters of polyol with >95% yield. The base stocks exhibited very high viscosity indices (187.288 to 187.687), excellent pour point (-25 to -40 °C) and high flash points (212 to 317 °C) required for a variety of industrial applications namely metal working, hydraulic, forging, cutting fluid, gear oil applications. The tribological properties of PDCO, exhibited very low WSD (0.72-0.79 mm) and WSVs (0.82-0.83 mm3) with high load carrying capacities (180-220 kg) indicating low friction and less energy losses between the sliding surfaces. This was also accompanied by very high thermo-oxidation stabilities [Oxidation stability (230-242 °C); Onset temperature (300-381 °C)] of the base stacks due to branching. Overall all the PDCO isoalkyl and polyol esters exhibited excellent properties suitable for a wide range of industrial applications on par with mineral oil based lubricants.
