topofmurrayhill Posted February 20, 2008 Share Posted February 20, 2008 I have a pretty simple question but the answer seems hard to find.There are lots of explanations and even animations on the web that explain the saponification reaction for triglycerides, resulting in three soap molecules and a glycerin molecule. It's basically very easy to understand.Now, triglycerides are fats. Three fatty acid chains attached by a glycerol backbone. When your palm oil fractionates in a cool room, the solid stuff is mostly palmitic and stearic acid in the form of a fat or triglyceride (palm stearin). The liquid stuff is mainly oleic acid triglyceride (palm olein).However, you can also have fatty acids as individual molecules instead of combined into triglycerides. That's called a free fatty acid and it's what you get for instance when you buy stearic acid. Free fatty acids can be saponified too and in fact we occasionally talk about using stearic acid in soaping.What I'm looking for is an explanation of how the saponification reaction works with free fatty acids vs. triglycerides and how it differs. Quote Link to comment Share on other sites More sharing options...
Beth-VT Posted February 20, 2008 Share Posted February 20, 2008 Top, if you don't get an answer here, post it over on The Dish. I know there are many people over there with extensive chemistry backgrounds that can probably explain it backwards, forwards and inside out. Quote Link to comment Share on other sites More sharing options...
topofmurrayhill Posted February 20, 2008 Author Share Posted February 20, 2008 Thanks, I did that this morning. I'll keep my fingers crossed. Quote Link to comment Share on other sites More sharing options...
CareBear Posted February 20, 2008 Share Posted February 20, 2008 go check! Quote Link to comment Share on other sites More sharing options...
itsmejeffd Posted February 20, 2008 Share Posted February 20, 2008 My Step-Mother-In-Law is a chemist at M.D. Anderson in Houston, TX. I'll pass your question on to her and keep you posted. Might take a day or two depending on how she's feeling. She's recovering from a recent surgery. Quote Link to comment Share on other sites More sharing options...
topofmurrayhill Posted February 20, 2008 Author Share Posted February 20, 2008 Thanks very much Jeff, but I just got the answer.The free fatty acid has a hydrogen atom where it would usually (in nature) be attached to the glycerol backbone. It loses the hydrogen to become a sodium (or potassium) salt and the H+ and the OH- (from the caustic) combine to form water.When you use free fatty acids like stearic, that portion of your recipe is forming soap & water rather than soap & glycerin when it's saponified. Quote Link to comment Share on other sites More sharing options...
8-GRAN-ONES Posted February 20, 2008 Share Posted February 20, 2008 Top..is that good or bad..to form soap and water, rather than soap and glycerin??? Quote Link to comment Share on other sites More sharing options...
TexasBrat Posted February 20, 2008 Share Posted February 20, 2008 For future use this guy has great information on his site about soapmaking.http://waltonfeed.com/old/soap/soapchem.html Quote Link to comment Share on other sites More sharing options...
CareBear Posted February 20, 2008 Share Posted February 20, 2008 For future use this guy has great information on his site about soapmaking.http://waltonfeed.com/old/soap/soapchem.htmldarn you. now it's 12:09 and I'm still up!! Reading this stuff is totally addictive! Quote Link to comment Share on other sites More sharing options...
Vio Posted February 20, 2008 Share Posted February 20, 2008 OMG what a great link!!! That guy really knows hiss stuff too. Thanks for posting that! Quote Link to comment Share on other sites More sharing options...
Camay Posted February 20, 2008 Share Posted February 20, 2008 Damn, I actually am a chemist, and I missed my opportunity to wow you all with my chemical knowledge. Next time... Quote Link to comment Share on other sites More sharing options...
topofmurrayhill Posted February 20, 2008 Author Share Posted February 20, 2008 Top..is that good or bad..to form soap and water, rather than soap and glycerin???I wouldn't call it good or bad. Whether it matters depends on what you're doing. Under some circumstances you might just need to know.The only relevant thing I've seen come up around here is adding stearic acid to harden the bar. In the case of a few percent I don't suppose it would be a significant consideration. Quote Link to comment Share on other sites More sharing options...
topofmurrayhill Posted February 20, 2008 Author Share Posted February 20, 2008 Damn, I actually am a chemist, and I missed my opportunity to wow you all with my chemical knowledge. Next time...Does that mean you'll wow me any time I want? Quote Link to comment Share on other sites More sharing options...
Camay Posted February 21, 2008 Share Posted February 21, 2008 For you, anytime... Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.