Behenyl palmitate is a saturated very-long-chain wax ester formed by esterification of palmitic acid (C16:0) with behenyl alcohol (C22H45OH). This compound extends the wax lipid series with pronounced chain asymmetry beyond stearyl palmitate. Derived from rapeseed or palm sources, it is a high-melting emollient providing robust structuring in formulations requiring thermal resistance superior to shorter homologs.
Chemical Structure
Behenyl palmitate has the molecular formula C38H76O2 and a molecular weight of 565.01 g/mol. Its structure—CH3(CH2)14COO(CH2)21CH3 (docosyl hexadecanoate)—features 36 rotatable bonds, one ester linkage, no hydrogen bond donors, TPSA 26.3 Ų, and XLogP3 18.4. These properties enable tight β-crystalline packing via extended C22 alcohol chains dominating intermolecular forces.
Physical Properties
Behenyl palmitate is a white hard waxy solid with a melting point of approximately 50–55°C. Its predicted boiling point is 569°C and density is 0.857 g/cm³. It remains insoluble in water but dissolves in hot chloroform and hydrocarbons. Low volatility and a high flash point (>200°C) support melt processing. NMR analysis confirms ester connectivity (δ 4.02 ppm -CH2O-, 1736 cm⁻¹ C=O stretch).
Synthesis and Production
Behenyl palmitate is produced through acid- or enzyme-catalyzed condensation of palmitic acid and behenyl alcohol, followed by purification by distillation to achieve >99% purity. Its vegetable origins also support RSPO sustainability certification.