[AlterVegan]

I have been searching endlessly for the answer to this question online and can't seem to find it anywhere: What is the difference between soap made from coconut oil (or palm oil) and cetyl alcohol? Everything that I have been able to find on cetyl alcohol states that it is formed from the saponification of coconut or palm oil (though originally from spermaceti). How, then, does it differ from soap made from the saponification of coconut or palm oil?

From what I've read, it seem that the difference may be that the glycerin remains attached in cetyl alcohol..? How does the process differ, then?

I'd appreciate any help with this! It may seem crazy but figuring out the chemical processes in 'cosmetic' ingredients has become my white whale, it seems

[Dan]

Coconut oil is mostly made up of triglycerides. These are triesters of glycerol (= glycerin) and long to medium chain fatty acids:



Saponification of these oils (let's say with KOH) produces carboxylate salts of the acids, along with glycerol:



Saponification of palm oil will not produce cetyl alcohol, cetyl alcohol is a completely different kind of molecule:



Where R1 = C₁₅H₃₁. This is made from the reduction (usually catalytic hydrogenation) of palmitic acid derivatives (such as the triglycerides in palm oil).

[fledarmus]

Further to Dan's post, I suggest you check the Wikipedia articles on coconut oil, palm oil, and cetyl alcohol, paying particular attention to the composition of palm oil. The R1, R2, and R3 that Dan shows can be a number of different groups, but are mostly either palmitic acid and oleic acid. Palmitic acid is a saturated C₁₆ straight chain carboxylic acid that can be chemically reduced to the alcohol, giving cetyl alcohol.

So yes, most cetyl alcohol comes from palm oil, but it is a more complicated process - the palm oil is saponified as described by Dan, the palmitic acid is separated, and then chemically reduced to form cetyl alcohol.

So soap made from cetyl alcohol will contain only the cetyl alcohol - soap made from saponification of palm oil will contain glycerol and a mixture of fatty acids composed mostly of palmitic acid and oleic acid. The two soaps should be completely different.

Coconut oil contains smaller R groups than palm oil - it is mostly lauric (C₁₂) and myristic (C₁₄) acid. You will not be able to make cetyl alcohol easily from either of these.