Submitted to: Industrial Crops and Products
Publication Type: Peer reviewed journal
Publication Acceptance Date: 9/27/2005
Publication Date: 4/3/2006
Citation: Hwang, H., Erhan, S.Z. 2006. Synthetic lubricant basestocks from epoxidized soybean oil and guerbet alcohols. Industrial Crops and Products. 23:313-317. Interpretive Summary: This research has focused on solving the major problems of soybean oil, inadequate oxidative stability and poor low- temperature properties for utilization as lubricants. In our previous paper, it was proven that chemical modification of epoxidized soybean oil improves oxidative stability and low-temperature properties. Our continuing efforts to develop lubricant base stocks from soybean oil resulted in products with oxidative stabilities and low-temperature properties comparable to commercial synthetic lubricants. We also studied the correlation between pour points and structural variation in the products. This study provides scientists with a new method for improving oxidative stability and low- temperature properties of a vegetable oil-based lubricant through chemical reactions. Development of vegetable oil- based lubricants through this new method would not only reduce dependence on non-renewable imported oil but also reduce concerns about the health and environmental hazards of used lubricants that are released into the environment because lubricants based on vegetable oils are non-toxic and biodegradable.
Technical Abstract: Synthetic lubricant basestocks with oxidative stabilities and pour points comparable to commercial synthetic lubricant basestocks have been prepared by reaction of epoxidized soybean oil with Guerbet alcohols. Four different Guerbet alcohols, C12-C14-, C16-, and C18-Guerbet alcohols, have been used in this study. Reaction of epoxidized soybean oil with a Guerbet alcohol in the presence of a catalytic amount of sulfuric acid provided ring-opened products. 1H NMR has shown that transesterification follows after ring-opening reaction under the given reaction conditions. Two types of ring-opened products, 0%- and 100%- transesterified products, could be obtained under controlled reaction conditions. Pour points of the ring-opened products ranged from -18 to -36C without pour point depressant (PPD) and from -21 to -42C with 1% of PPD. Acetylation of hydroxy groups in the ring-opened products further lowered pour points that ranged from -27 to -42C without pour point depressant (PPD) and from -30 to -48C with 1% of PPD. Oxidative stability was examined using a modified Penn State micro-oxidation test and compared with those of synthetic lubricant basestocks and mineral oil. Oxidative evaporations of two selected products in the micro- oxidation test were similar to mineral oil and less than synthetic lubricant base oils, PAO4 (polyalphaolefin) and diisododecyl adipate. Deposits of these products were similar to synthetic lubricant base oils and less than mineral oil.