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

Submitted to: Journal of ASTM International
Publication Type: Abstract
Publication Acceptance Date: March 12, 2009
Publication Date: N/A

Technical Abstract: Large-scale production of biodiesel has led to a surplus of glycerol, so new commercial uses of this co-product are under development. Increased utilization of glycerol would help biodiesel producers to become more competitive and viable. Lubricants based on vegetable oils generally suffer from poor low temperature and oxidative stability properties in comparison to lubricants prepared from petroleum-based materials. Consequently, improvement of low temperature properties of vegetable oil-based lubricants such as pour point (PP) is desirable. Moreover, as a result of their higher PP, the usage of vegetable oils as lubricant base-stocks is limited. In order to find value added utilization of glycerol as well as to improve the low temperature properties of vegetable oil-based lubricant base-stocks, the current work was undertaken. With this in view, initially 15 different vegetable oils were screened using glycerol tris(2-ethylhexanoate) [GTEH] as a diluent to improve the low temperature properties at 25 and 50 weight percent (wt%). Maximum improvements in PP of 16 and 90C were in epoxidized soybean oil and palm oil correspondingly obtained with 50 and 25 wt % GTEH The top five vegetable oils with maximum improvements in PP were studied further at lower concentration of GTEH. The variation in PP in response to GTEH is attributed to variations in the fatty acid compositions of the vegetable oils. This study demonstrates that addition of glycerol triester derivatives improves the PP of epoxidized soybean oil and palm oil significantly. Both of these oils have better oxidative stability in comparison to soybean oil, so they are more suited as components in formulations of industrial lubricants.