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Topic: fatty acid salts  (Read 14576 times)

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Offline science2000

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fatty acid salts
« on: January 26, 2006, 12:28:46 AM »
Has anyone here created metal salts of fatty acids? Are they stable, interesting, water soluble?
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Offline Yggdrasil

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Re:fatty acid salts
« Reply #1 on: January 26, 2006, 03:58:09 AM »
Sodium and potassium salts of fatty acids have been made for ages and are common household items.  They are more commonly known as soap.
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Offline Alberto_Kravina

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Re:fatty acid salts
« Reply #2 on: January 28, 2006, 06:16:28 AM »
Quote
Has anyone here created metal salts of fatty acids? Are they stable, interesting, water soluble?
I tried to make a fatty acid salt with normal oil and solid NaOH in a pot some time ago. The end product was a grey cheese-like substance.
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Offline Borek

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Re:fatty acid salts
« Reply #3 on: January 28, 2006, 06:22:56 AM »
Hard water? What you described sounds like calcium or magnesium salt precipitate.

But then sodium salts must have limited solubility too.
« Last Edit: January 28, 2006, 06:26:11 AM by Borek »
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Offline Alberto_Kravina

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Re:fatty acid salts
« Reply #4 on: January 28, 2006, 06:26:02 AM »
Quote
Hard water? What you described sounds like calcium or magnesium salt precipitate.
I know, I know...that was kind of confusing me...the pot was clean and the reaction was made in absence of water...  :-\
After I performed this "synthesis" I dissolved the substance in water and analyzed the sample if there were any Calcium or Magnesium cations....but nothing!
« Last Edit: January 28, 2006, 06:27:43 AM by Alberto_Kravina »
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Offline Borek

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Re:fatty acid salts
« Reply #5 on: January 28, 2006, 06:28:57 AM »
Well, if there was no watewr how do you want the resulting salt to be dissolved ;)

Besides - there is no way to hydrolize fat without water. Strong base catalyse the reaction and removes acid moving equilibrium to the right, but hydrolyzis is a reaction of fat with water.
« Last Edit: January 28, 2006, 06:30:23 AM by Borek »
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Offline Alberto_Kravina

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Re:fatty acid salts
« Reply #6 on: January 28, 2006, 06:35:37 AM »
Hmm...I'll try to make the same thing with KOH today, I think that it will work better, also, I'll make the reaction at 40-50 Celsius dgrs. Do you guys have any idea of what I should add to the salt to make it look like/smell like "normal" soap?
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Offline Borek

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Re:fatty acid salts
« Reply #7 on: January 28, 2006, 06:41:34 AM »
« Last Edit: January 28, 2006, 06:42:16 AM by Borek »
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Offline Alberto_Kravina

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Re:fatty acid salts
« Reply #8 on: January 28, 2006, 06:50:47 AM »
hehe....Google is the solution to all our problems...

Well, I'll tell you the results as soon as I have finished the synthesis (I started five minutes ago  :D )
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Offline Yggdrasil

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Re:fatty acid salts
« Reply #9 on: January 28, 2006, 03:58:40 PM »
Making fatty acids salts from vegetable oil may produce a different product than making soaps because soaps are made from the hydrolysis of animal fat, which has a different composition than vegetable oil.  Vegetable oils have more unsaturated fatty acid chains than animal fat, so the resulting salts will have different properties.
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Offline Alberto_Kravina

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Re:fatty acid salts
« Reply #10 on: January 29, 2006, 09:35:09 AM »
This time it worked! The product was a soap-like white substance.  :)
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Offline science2000

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Re:fatty acid salts
« Reply #11 on: January 29, 2006, 10:27:51 PM »
I'm still unsure what it is about fatty acid soaps that kills the germs on our hands. Does anyone know?
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Offline pantone159

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Re:fatty acid salts
« Reply #12 on: January 29, 2006, 11:27:29 PM »
Quote from: science2000 on January 29, 2006, 10:27:51 PM
I'm still unsure what it is about fatty acid soaps that kills the germs on our hands.

Nothing, actually.  They allow the layer of oil on our hands, which contains said germs, to be washed away, thus removing the germs.
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Offline qlabel

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Re:fatty acid salts
« Reply #13 on: February 04, 2006, 05:08:35 AM »
I also want to try this synthesis! It´s cool! Which oil should I use?
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Offline Alberto_Kravina

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Re:fatty acid salts
« Reply #14 on: February 04, 2006, 05:16:29 AM »
Quote from: qlabel on February 04, 2006, 05:08:35 AM
I also want to try this synthesis! It´s cool! Which oil should I use?
Try with any commercial oil. I tried it with olive oil and penut oil and it worked. Also, try with NaOH and KOH (If you can).
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