Oleyl palmitate is a monounsaturated wax ester formed by esterification of palmitic acid (C16:0) with oleyl alcohol (C18:1 cis-9). This introduces unsaturation into the wax lipid series between oleyl oleate and saturated homologs such as myristyl myristate. As a plant-derived emollient sourced from palm and olive oils, oleyl palmitate combines saturated chain stability with monounsaturated fluidity, providing lightweight occlusion ideal for modern cosmetic formulations.
Chemical Structure
Oleyl palmitate has the molecular formula C34H66O2 and a molecular weight of 506.89 g/mol. Its structure, CH3(CH2)14COO(CH2)7CH=CH(CH2)7CH3 (cis-Δ9), contains 31 rotatable bonds and one cis double bond. It has no hydrogen bond donors, a TPSA of 26.3 Ų, and an estimated XLogP3 of ~15.5. The cis unsaturation introduces a kink that reduces crystallinity while maintaining lamellar organization.
Physical Properties
Oleyl palmitate is typically a pale yellow, low-melting waxy solid or viscous liquid, with a melting point around 15–20°C. It has an approximate density of 0.86 g/cm³ and a predicted boiling point near 550°C. It is insoluble in water but miscible with oils, ethanol, and chloroform. Compared to saturated wax esters such as cetyl palmitate (melting point ~54°C), the cis unsaturation lowers packing density, producing softer films and enhanced gloss with a refractive index around 1.45.
Synthesis and Production
Oleyl palmitate is produced through acid- or lipase-catalyzed condensation of palmitic acid and oleyl alcohol derived from vegetable oils. Purification is commonly achieved by molecular distillation, yielding purities above 98%. Structural confirmation is obtained by NMR spectroscopy, showing characteristic olefinic signals (¹H δ5.32 ppm, ¹³C δ130.6 ppm for C=C) and a carbonyl resonance at δ173.2 ppm.
