Cetyl stearate is a saturated long-chain wax ester formed by esterification of stearic acid (C18:0) with cetyl alcohol (C₁₆H₃₃OH). It is positioned as an intermediate in the simple wax lipid series between stearyl stearate and lauryl laurate. This vegetable-derived emollient, commonly sourced from palm or coconut feedstocks, balances the fluidity of shorter esters with the structure of longer homologs, making it ideal for texture modification in personal care formulations.

Chemical Structure

Cetyl stearate has the molecular formula C₃₄H₆₈O₂ and a molecular weight of 508.90 g/mol. Its structure—CH₃(CH₂)₁₆COO(CH₂)₁₅CH₃—features 32 rotatable bonds, two hydrogen bond acceptors, no donors, TPSA 26.3 Ų, and XLogP3 16.3. These properties promote stable β-crystalline lamellae through van der Waals interactions along the asymmetric C16/C18 chains.

Physical Properties

Cetyl stearate is a white, odorless waxy solid with a melting point of approximately 57°C and a boiling point near 380°C at reduced pressure. With a density of ~0.85 g/cm³, it dissolves readily in hot ethanol, chloroform, and oils but remains insoluble in water (log₁₀WS -12.92). Its fusion enthalpy (Δ_fusH ~87 kJ/mol) and vaporization enthalpy (Δ_vapH ~100 kJ/mol) support smooth phase transitions, while its low volatility ensures stability during melt processing.

Synthesis and Production

Industrially, cetyl stearate is synthesized through acid- or lipase-catalyzed esterification of stearic acid and cetyl alcohol, achieving purities greater than 98% via molecular distillation. Enzymatic production methods, such as those using Rhizomucor miehei lipase, favor vegetable-derived origins and contribute to sustainability in manufacturing.