Isopropyl myristate is a branched short-chain ester derived from myristic acid (C14:0) and isopropanol. Unlike linear wax esters such as hexyl laurate, its isopropyl headgroup confers low viscosity and enhanced skin penetration. Widely used as a “dry touch” emollient, it mimics the lighter fractions of sebum while solubilizing active compounds in oil-free systems, bridging both cosmetic and pharmaceutical applications.
Chemical Structure
Isopropyl myristate has the molecular formula C17H34O2 and a molecular weight of 270.45 g/mol. Its structure—(CH3)2CHOO(CH2)12CH3—includes a bulky isopropyl ester and a long acyl chain with 13 rotatable bonds. Key physicochemical parameters include a TPSA of 26.3 Ų, a LogP of 7.71, and no hydrogen bond donors, resulting in a conical molecular shape that promotes disordered lamellar phases compared to symmetric linear esters.
Physical Properties
This compound is a clear, colorless, low-viscosity liquid with a melting point of approximately 5°C. It boils at 193°C (20 mmHg) or around 258°C under atmospheric pressure. Additional properties include a density of 0.85 g/cm³ and a refractive index ranging from 1.435 to 1.438. Isopropyl myristate is odorless when pure, insoluble in water, and miscible with oils, ethanol, and chloroform. Its flash point of 152°C supports safe industrial processing.
Synthesis and Production
Isopropyl myristate is commonly produced through esterification of myristic acid—typically sourced from coconut or palm kernel oil—with excess isopropanol under acid catalysis (e.g., sulfuric acid). More sustainable enzymatic synthesis routes using lipases have also been developed, enabling dehydration-assisted reactions that achieve purities above 98% while allowing reagent recycling and greener production practices.
