Green synthesis of some novel dioxolane compounds from Indonesian essential oils as potential biogreases

Greases are mostly prepared from petroleum base stocks that make it toxic to the environment. The demand for green greases has led to in depth research of other renewable resources. Vegetable oils are promising candidates due to their renewability and low toxicity. However, it has poor oxidation stability and high total acid number. One way to solve this problem is chemical modification of its fatty acid structure. We report some novel dioxolane compounds from oleic acid and benzaldehyde derivates from some Indonesian essential oils via several steps, i.e: hydroxylation, esterification and acetalization. The esterification and acetalization reaction was carried out by green procedure using sonochemical method and montmorillonite KSF as a catalyst. Hydroxylation of Oleic acid was performed by KMnO₄ to give 9,10-dihydroxyoctadecanoic (DHOA) in 47% yield. The esterification was done using methanol yielded methyl 9,10-dihydroxyoctadecanoate (MDHO) as white powder in 94%. Acetalization of the ester MDO with various benzaldehyde derivatives was carried out to give the dioxolan derivatives in the range of 17 – 60% yield. All of the structure was confirmed by FT-IR and GC-MS, meanwhile their physicochemical properties were determined using ASTM methods. From physicochemical properties, i.e: -TAN, TBN and IV-, it can be concluded that these novel compounds have the potential to be developed into biogrease.