[chemi05]

Does anyone know how to obtain free form fatty acids from vegetable oils by means of deesterification or hydrolysis using everyday common household chemicals?

[hemispheredancer]

Do a google search for saponification and soap making.  It will give you all you need to know.

[chemi05]

That only leaves glycerin and soap. How would you then isolate the pure fatty acid?

[Garneck]

Just add some HCl. You'll get a fatty acid that doesn't dissolve in water and glycerin will dissolve in water.

[chemi05]

So in other words:

1) Vegetable Oil + NaOH = Soap & Glycerin

2) Soap & Glycerin + HCl = Free Form Fatty Acid & H2O + Glycerin

Correct?

[hemispheredancer]

Reacting triglycerides with a strong base will give you the fatty acids and glycerine.  In order to separate the fatty acids from the glycerine, acidify the solution with HCl.  The fatty acids are insoluble in water at low pH.  The glycerine is soluble in the water at a much wider range or pH.  This will cause the acid to crash out and the glycerine will stay in the water.  You can also do an organic extraction of the acidified water to recover any remaining fatty acids.  

[chemi05]

Last but not least, can these reactions be performed at room temperature or do they require heating? Thanks.

[hemispheredancer]

For the actual hydrolysis you will have to heat the solution to speed the process up.  For the isolation of the free acid it can be done at room temp.  There are plenty of websites that will give you step by step instructions for the saponification process.