ARS | Publication request: Glycerol Tri-Ester Derivatives as Diluents to Improve Low Temperature Properties of Vegetable Oils

Submitted to: Journal of ASTM International
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 14, 2010
Publication Date: May 5, 2010
Citation: Shah, S.N., Moser, B.R., Sharma, B.K. 2010. Glycerol Tri-Ester Derivatives as Diluents to Improve Low Temperature Properties of Vegetable Oils. Journal of ASTM International. 7:1-10.

Interpretive Summary: This research reveals that adding glycerol (biodiesel co-product) derivatives significantly improves the low temperature flow properties of modified soybean oil (ESBO) and palm oil (PO). Large-scale production of biodiesel has led to a surplus of glycerol, so new commercial uses of this co-product are desired. Lubricants based on vegetable oils generally suffer from poor low temperature and oxidative stability properties in comparison to lubricants prepared from petroleum-based materials. As a result, improvement of low temperature properties of vegetable oil-based lubricants is advantageous. This along with better oxidative stability enhances the use of vegetable oils as environmentally- friendly lubricant basestocks. The current study demonstrates value-added utilization of glycerol and may ultimately help biodiesel producers to become more competitive and viable.

Technical Abstract: Large-scale production of biodiesel has led to a surplus of glycerol, so new commercial uses of this co-product are being sought. Twenty four vegetable oils were screened using glycerol tris (2-ethylhexanoate) [GTEH] as a diluent to improve the low temperature properties. Epoxidized soybean oil (ESBO) and palm oil (PO) have shown maximum improvements in pour points (PP) on addition of GETH as diluents. Maximum improvements in pour point (PP) of 16 and 9 deg C were observed in ESBO and PO, respectively, with 50 and 25 wt % GTEH. The five vegetable oils with maximum improvement in PP were studied further at lower concentration of GTEH. The variation in PP response to GTEH is attributed to variations in the fatty acid compositions of the vegetable oils. This study demonstrates the viability of using GTEH as diluents with vegetable oils to improve their low temperature properties. As ESBO and PO oils have better oxidative stability also in comparison to soybean oil, so their blends with GETH have more potential in formulations of industrial lubricants.