Long chain fatty acid: Palmitic acid (hexadecanoic acid)
This one is important in cosmetic chemistry as it’s in pretty much all our liquid oils, solid oils, and butters. It’s also used as a starting material for ingredients, like cetyl palmitate, stearyl palmitate, or isopropyl palmitate (all esters, which we’ll meet soon in this series).
The molecular formula is CH3(CH2)14COOH or C16H32O2
It has a melting point of 63˚C (145.4˚F), which is much higher than body temperature and room temperature.
You can find this in the solid oils and liquid oils in smaller percentages, but you’ll find it in butters like crazy!
For instance, we find it at lower than 10% in a lot of our liquid oils, like broccoli seed oil at up to 3.5%, borage oil at up to 4%, evening primrose oil at 6%, and at 10% or more in some of our higher viscosityoils, like olive oil at 10%, argan oil to 12%, and baobab oil at up to 30%.
It makes up 25% to 30% cocoa butter, 6% mango butter, and 3% to 7% shea butter.
Because it’s solid at room temperature, when we use oils that contain this fatty acid, we get a bit more occlusion on our skin, which helps prevent transepidermal water loss (TEWL). It’s not as greasy feeling or draggy as stearic acid.
Take a look at the liquid oils I have listed in the emollients section of the site to see more!