Sodium & Potassium Carbonate Experiment

SoapMakingForum

Help Support SoapMakingForum:

donniej

Well-Known Member
Joined
Aug 7, 2008
Messages
924
Reaction score
8
Location
Philadelphia, PA
I just finished several experiments using sodium carbonate (wash soda) and potassium carbonate (potash). These are the original alkilis used in saponification from the days before hydroxides. Potassium carbonate was derived from wood ashes, sodium carbonate from burning seaweed. I got potassium carbonate from a chemical supplier and the sodium carbonate as Arm & Hammer wash soda. I'm confident in the potassiums purity but I don't know the purity of the wash soda. Hey, it's what I had...

The first portion of the experiments was to get an idea as to there strengths compared to hydroxides. I did this via titration (pronounced ty-tray-shun). This is a test done by adding alkili and acid in the presence of a PH indicator. I used phenolpthalein as the indicator and vinegar (standard 5% acidity) as the acid in my first tests. Basically the question is how much vinegar does it take to nutralize 1 gram of lye (NaOH), caustic potash (KOH), wash soda (sodium carbonate, Na2CO3) and potash (sodium carbonate, K2CO3). The more vinegar it takes, the stronger the alkili must be.
Here are the results...

NaOH (lye) = 29ml vinegar
KOH (caustic potash) = 20ml vinegar
Sodium Carbonate (wash soda) = 10.5ml vinegar
Potassium Carbonate (potash) = 9ml vinegar
I also tested borax while I was at it, it took 3.5 - 3.75ml vinegar.

Now that I had an idea as to strength, it was time to work on saponification values. I work mostly with soybean oil so I used it's sap values which are .136 for NaOH and .19 for KOH. For 1 pound of oil, this equals 61.6g NaOH & 86 KOH. To minimize how much chemistry I needed, I divided by 10 to get 6.1g and 8.6g.

Nuetralization of fatty acids is slow and requires a lot of effort. To speed up the process I determined how much sulfuric acid was needed to nuetralize the saponification value of 6.1g NaOH and 8.6g KOH. Both required approximately 4.5ml of 93% sulfuric acid.
Therefore 4.5ml of sulfuric acid is a convenient substitute for 1/10 the saponication value of 1 pound of soybean oil.

To nuetralize the 4.5ml of acid took 8g potassium carbonate and 7.5 grams sodium carbonate. Therefore it should take approximately 80g potassium to saponify 1 pound soy and 75g sodium. BTW, there are 28g in an ounce.

Next I cooked each in a double boiler.... but nothing happened. After an hour I poured the potassium into a pot and cooked it. It's boiling temp was 230*F. It did saponify but not fully, I'm assuming I needed more. Unlike KOH, at no point did it ever thicken, it always stayed thin and watery. The sodium stayed in the double boiler for 2 hours with often stirring. There was no change and the next day it had separated.

Next I tried using equal parts potassium, oil and water. I got some soap curdles, maybe about 1/2 of the oil saponified but it was very slow, even at 230*F. As the water boiled off, the potassium fell out ot the bottom in a sand-like form. Adding water put the potassium back into solution. After about 1.5 hours I got tired and added sap value of KOH. This got it going but it still stayed very thin. After cooling however, it did get thick and eventually semi-solid. Lather was surprisingly good.
 

Vintageliving

Well-Known Member
Joined
Oct 1, 2009
Messages
232
Reaction score
3
Donnie, interesting experiment!

I've read that making soap with potash took a very long time, and that the soap went through several stages.

It's fascinating to read about. Thanks for posting your report.
 

Bubbles Galore

Well-Known Member
Joined
Aug 13, 2009
Messages
2,342
Reaction score
16
Location
Australia
Interesting Donnie. I wonder how the experiment would turn out using animal fat? I'm impressed with your patience. :wink:
 

donniej

Well-Known Member
Joined
Aug 7, 2008
Messages
924
Reaction score
8
Location
Philadelphia, PA
Vintageliving said:
I've read that making soap with potash took a very long time, and that the soap went through several stages.
If you have any info on this, please let me know. I could use it :D
 

Vintageliving

Well-Known Member
Joined
Oct 1, 2009
Messages
232
Reaction score
3
Donnie, I'll go through my bookmarks.

Here's one that mentions the stringiness:

http://www.cooks.com/rec/doc/0,1630,145 ... 97,00.html

If you do searches on the web for old-fashioned soap, Grandma's soap making, etc., you'll find all sorts of interesting, and some odd, things.

Here's one about how to test if the lye is ready:

http://www.countryfarm-lifestyles.com/make-lye.html

Here, two books online:

http://books.google.com/books?id=UQuAAA ... q=&f=false

http://books.google.com/books?id=sPQoAA ... 22&f=false

On Leblanc soda (there are other interesting pages on this site, too):

http://www.lenntech.com/chemistry/soda-industries.htm

On potash:

http://www.chemistryexplained.com/eleme ... ssium.html

Very detailed recipe:

http://www.cooks.com/rec/doc/0,1730,148 ... 98,00.html

Recipe with note about dipping boxes in cold water first:

http://www.cooks.com/rec/doc/0,1630,144 ... 97,00.html

Smoke points of fats and oils:

http://whatscookingamerica.net/Informat ... lTypes.htm

Various bits of info about old ways of making soap and washing:

http://www.oldandsold.com/articles11/mi ... es-1.shtml

Notes on soap making, which mentions 6-8 hours for process:

http://www.alcasoft.com/soapfact/historycontent.html

Good old recipes and general info:

http://florilegium.org/?http%3A//floril ... A-art.html

Posts about soapmaking and recipes, remarks, etc. at Florilegium:

http://www.florilegium.org/?http%3A//ww ... g-msg.html

There is more info at Florilegium.

Hope you can find some more links. It's taken a lot of "digging around" on the internet to find these.
 

Susie

Supporting Member
Joined
Aug 1, 2013
Messages
9,531
Reaction score
8,869
Location
Texas
This is a thread from 2009, I doubt you are going to get any responses.
 

cherrycoke216

Well-Known Member
Joined
Jun 22, 2014
Messages
561
Reaction score
456
Sodium & Potassium Carbonate Experiment

This is a thread from 2009, I doubt you are going to get any responses.

I think it's a click bait. The Thai word is a link. I did not click it on my phone. But administrator or people with AdAware or the likes might want to look into it. This ID post 2-4 links in His post.
ETA: Oopsie! Sorry! Susie! Didn't notice that. I was trying to tell the admin about the "nearly invisible" links he puts where the signature line often is. This is a cleaver trick for spam... I can only see it because phone app probably won't do the undercover color for his link.
 
Last edited:

Susie

Supporting Member
Joined
Aug 1, 2013
Messages
9,531
Reaction score
8,869
Location
Texas
That post was in 2009. The purpose of telling someone that the thread is old is to let the thread go back to being a dead thread.
 

DeeAnna

Well-Known Member
Joined
Feb 20, 2013
Messages
12,150
Reaction score
16,548
Location
Northeast Iowa, USA
Susie -- Cherrycoke is trying to explain that the post from Andyson is spam. If you look closely in the supposed blank space below the person's words, you'll some pale gray characters (Thai?) with a link to fullhdtekparcaizle dot com This person's other posts also contain this link.
 
Top