Behenyl behenate is a saturated very-long-chain wax ester synthesized from behenic acid (C22:0) and behenyl alcohol (C22H45OH), exemplifying the fatty acid–long chain alcohol structure characteristic of simple waxes. This high-purity emollient, derived from vegetable sources such as rapeseed, extends the wax ester series beyond stearyl stearate, offering exceptional thermal stability and film-forming properties for advanced cosmetic and pharmaceutical formulations.
Chemical Structure
Behenyl behenate possesses the molecular formula C44H88O2 and a molecular weight of 649.18 g/mol. Its linear ester structure—CH3(CH2)20COO(CH2)21CH3—features 42 rotatable bonds, zero hydrogen bond donors, a TPSA of 26.3 Ų, and extreme lipophilicity (XLogP3-AA 21.7). These properties enable tight β-crystalline lamellar packing, with the InChIKey NJIMZDGGLTUCPX-UHFFFAOYSA-N confirming its identity as docosyl docosanoate.
Physical Properties
This compound appears as white to yellowish hard waxy granules or powder, with a melting point of 70–75°C, density of 0.856 g/cm³, and a predicted boiling point of approximately 627°C. Behenyl behenate is odorless with low vapor pressure, insoluble in water, but soluble in hot chloroform, hydrocarbons, and vegetable oils. Its high complexity (544) and monoisotopic mass of 648.678 support LC-MS identification through characteristic behenic acid fragments (m/z 339.3, neutral loss 310 Da).
Synthesis and Production
Industrially, behenyl behenate is produced via acid- or enzyme-catalyzed esterification of behenic acid and behenyl alcohol. Candida antarctica lipase B (CALB) is often preferred for its regioselectivity, accommodating long C22 chains efficiently. Distillation processes yield products with purity greater than 99%. Structural confirmation of the ester linkage is achieved by HMBC NMR, showing correlations between ¹H δ4.05 ppm and the ¹³C δ174 ppm carbonyl signal.
