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Crystallization of homemade sodium acetate

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(Updated - see end, below)

If you've ever wanted to play around with sodium acetate, but you're too much of a nerd to simply go online and buy some from a chemical supply house - noooo, that'd be too easy, you want to make it, from scratch - then this instructable is for you.

Inside, I show the whole process, from baking soda and vinegar, through concentration and filtering, to final crystallization.

(Please note that you, not I, explicitly assume all risk associated with playing with chemicals, fire, or hot things. Use common sense. If you're not an adult, enlist the help of a parent. If you're an idiot, close your browser now before you burn yourself. And regardless, by reading any of the suggestions contained herein, you implicitly assume full responsibility for any and all accidents, burns, lacerations, ruptured spleens, loss of consciousness, death, shin splints, hangovers, spurned advances, or insolvency that may result. Seriously... use your brain.)

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Update: When I first wrote this Instructable, I somehow got it in my mind that acetic acid had a boiling point that was slightly lower than water - this is incorrect! Acetic acid (ethanoic acid) has a boiling point of 118.1 C. This may change some steps and I may amend the instructions after I've had a chance to play with a few things; for now, though, when I talk about acetic acid boiling off in some of the steps, take it with a grain of salt (or at least sodium bicarbonate). :-)
 
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I think the most of the Dark Color your Getting is because of the Formation of Iron Salts with your pot... Aluminium, Glass or Teflon should work without that effect...

It is just a thought but is supported by a claim by a prior comment here, and I quote:

"I just made some 1/9/11 and I boiled over a medium heat and it came out clearer. I did 2 batches the first one I added the vinegar to the baking soda and that batch seemed darker, but the second batch I slowly added the baking soda to vinegar and it was clearer and a different consistency of crystal formation too. Give it a try and see what happens. Good luck. I did boil about 90 percent off too."

I believe he got a better result the second time because he more fully neutralized the acid reducing Iron salt formations...

Just a theory but it might help...

teachme!4 years ago
ok im going to sound really stupid but why do the crystals get hot when they crystalise im wondering?
it has to do with "supercooling"

And Exothermic raection...

MAR!3 years ago
About at what temp. should i boil this?
ycsmela MAR!3 years ago
I just made some 1/9/11 and I boiled over a medium heat and it came out clearer. I did 2 batches the first one I added the vinegar to the baking soda and that batch seemed darker, but the second batch I slowly added the baking soda to vinegar and it was clearer and a different consistency of crystal formation too. Give it a try and see what happens. Good luck. I did boil about 90 percent off too.

I believe because when their is still acid in the Vinegar it make salts with the iron giving it a dark huegh...

MAR! ycsmela3 years ago
But yours did crystallize like it should, right? Not just dehydrate and turn to mush in the pot? My stove has numbers so to me med high is a little over 3.
Heres how 4 attempts ended in my case, help me please.
Sodium acetate in solid form..JPG
hi i just did yet another batch, as my vinegar had sediment in it, i filtered it and it did crystalise afterwards, but still a bit mushy. I recharged it by boiling it down, and have a bottom layer of milky white slimey substance - the brown amber liquid sits on top - what is this?
hi i have asked a few questions on other instructables, i know all experiments are done differently but following nurdrage he uses 1litre vinegar to 3tbls bicarb soda. i have converted yours and you use 1 gallon (3.7l) vinegar to 12 oz ( 20 tbls ) bicarb soda.
Why do you use so much more bicarb soda? and is this why with me using 3 tbls my hot ice is not solidifying but going mushy? thanks
bumsugger2 years ago
Can anyone tell me the prime use for this chemical,as it appears to have slipped my mind? Thanks.
this is used in re useable heat pads, the ones that crystallise and heat up when you snap the little metal disc.
Johenix4 years ago
Why not use washing soda, sodium carbonate?  It has twice the sodium content.
If the chemical formula is different it could change the reaction. It may give the same product in the same quantities, but you would have more waste material, or you would get a bit more product but using alot more vinegar. I don't know the chemical formula for washing soda, but these are some reasons why it might not be used...
I've used washing soda for this.

Checked it, the formula: Sodium Bicarbonate Decahydrate

So it's no problem.
leontom12 years ago
Is This Used To Make Hot Ice????
pc52 years ago
maybe you had trouble seeding "supersaturated solution" because it wasnt supersaturated, if u attempted to seed after using the activated charcoal, which may adsorb your desired product? Just an idea.

I'm skimming, appreciate the cool instructable :)

--PC
skulendran2 years ago
hey, i was just wondering. you said if you heated the crystals, water would be driven off and it would produce a white powder (anhydrous sodium accetate). but how would you go about doing that? could i just put the crystals in a pan on low heat?
julsscott3 years ago
can this be done as a school project? can you do the prep at home and then have a deminstration of some sort at school? How would that work,,,,,,any suggestions?
I thought that once all impurities and contaminates are removed it would turn into a slightly tinted clear solution, not stay amber colored.
At least, that's what pure, lab grade sodium acetate should look like....Is there a way to achieve that?
If you look at store bought manufactured hot packs that use Sodium Acetate, they are almost always amber too. Don't know why but they are, so I think its safe to say that it doesn't matter if you can get it clear or if it stays amber colored.
Wesley6663 years ago
I was just screwing around and wrote out the vinegar and baking soda reaction equation and realized you could make hot packs with the product. Then I checked Instructables to see if anyone had done it, and they had. Darn, thought I had a really good, original idea too...

Good 'Ible though! :D
Erebo20053 years ago
Good, clear and simple. Thanks
LISTEN EVERYONE!!! LISTEN, LISTEN! IF YOU WANT IT TO BE CLEAR (NOT DARK OR BROWN) YOU WILL DO ALL THE SAME BUT REDUCE TEMPERATURE OF BOILING AND INCREASE TIME!!! :=)
ryanmuller4 years ago
All other sodium acetate I've seen dissolves clear in water... is there any way to achieve this? I need it to look like plain ordinary water.
For a "water" look, you will need either: laboratory grade chemicles or to buy it online. About 500 grams is like $25 If you need help, consult youtube :)
robot7974 years ago

can you eat it?

briannac14 years ago
Do we HAVE to have activated charcoal?
No, look at NerdRage's video.
hawk 1sr4 years ago
i followed the directions, but some how i just have yellowish-gold substance that wont melt all the way and theres chunks of the krystals that i cant get rid of.  Your stuff was clearish, mines not. what did i do wrong?
Pizzapie5004 years ago
Cool! But I'm not "too much of a nerd" so I bought the sodium acetate of ebay. For some reason, mine was like 20 times faster than yours, and it would go off w/o me putting a crystal in it. I made this like a year ago and kept some in my fridge. Do you think I can bring it to school to show my teacher? Or will it go off in my backpack?
I Just wanna ask if i can use Paper towels instead of coffee filters!!! I'll comment again if I am successful P.S. If i misspelled successful or misspelled its because i'm Greek! 
ryguy4285 years ago
For 1 gallon of white vinegar, what's the yield of dry sodium acetate? Assuming vinegar has a density of 1 g/mL, I'm getting a theoretical yield of about 250 g sodium acetate.
Water is 1g/ml; acetic acid is 1.049 g/ml; distilled white vinegar (in the US) is 5% acetic acid - easy math: 1.00245 g/ml (close enough to 1 for government work).

Sodium Acetate is C2H3NaO2, molar mass 82.03g; density 1.528 g ml ^-1
Acetic Acid is C2H4O2, mm is 60.05, density already given above.
Sodium Bicarbonate is CHNaO3, mm 84.01, density 2.173
Water: If you (anyone, not ryguy428) don't know formula or density of water, you're NOT ready to try chemistry. Or graduate from secondary school. Or vote. Molar mass is trickier - it's about 18.0152833 - depending on a few things... ;-)

Rxn: CH3–COOH + Na+[HCO3] → CH3–COO Na+ + H2O + CO2

Do the molar balance, substitute for density, and you'll get theoretical yield.
(Hint: 84g of soda should give about 82g of sodium acetate. If you were using 8% vinegar, you'd need about 750ml. If you can make that calc come out right, do it for 5% and you'll have your answer.)

Nice explanation of the sums! Very clear.

A tad harsh about the assumed knowledge though, there are lots of bright and creative people who don't need that info.

What things did you have in mind for the water that would affect the mass within the accuracy limits and significant figures of your other data?
A) Thanks!

B) I'm reminded of the story that someone asked Einstein what the quadratic equation was and he (supposedly) said "I know where to look it up - why should I bother memorizing it?"

<inappropriate political rant> I shudder to think, though, that one can get through high school without knowing that water is H2O, and the absolute *basics* of the metric system (i.e., that mass, length, and volume (and, in fact, temperature and energy, by extension) are tied together by the single, simple fact that 1 cc of water weighs (masses, actually) one gram. Now, I was being a wee bit sardonic, but -- heck, the U.S. makes people applying for citizenship learn all kinds of stuff that (generously) 40% of voters couldn't answer. I sure don't want people voting on global warming, stem-cell research, and energy policy, if their scientific knowledge base doesn't include the absolute scrapings from the bottom of the barrel... ;-) </ inappropriate political rant>

More fairly - I liked Heinlein's quote (Google "specialization is for insects"). IMHO, and only my opinion, no adult in the modern world should be considered educated without a grasp of some plurality of some basic knowledge set. Defining that is politically 'difficult' - but I stand by the concept:

Things are made of atoms. The earth is round and goes around the sun, because of gravity. Traits that help survival get passed on. Wood burns, which gives light, warmth, and tasty food. Men and women think and prioritize differently. (Some) germs cause (some) diseases. Too much sunlight is bad for you (as is not enough). Stay away from wild animals. Seeds grow into plants, which need light and water. Don't eat wild mushrooms, or build a fire in an enclosed area. Yadda yadda. And water is H2O.

C) Nothing - given your stated constraints. Hence my smiley-face. I was winking at those who'd say something about "well, that's liquid phase - it's more like 0.917 as solid - you have to say at s.t.p. (or, more accurately, at the triple-point). And - what about deuterium content? And never mind supercooling, or allotropic forms....

A : You're welcome :) It's great to see someone apply some real analysis instead of just spouting second hand partially realised facts.

C : I know, and apologise.

I was baiting you a bit about showing off your (absolutely correct, by the way) knowlege.   :)
The constraints in fact were outlined by your good self in terms of the sig. figs., phase and isotopic accuracy you supplied for the other reagents.  Naughty of both of us, I apologise. ;)

B : (sorry about the chaotic order, this reply is harder to compose since it's more subjective than A or B!)

An interesting one and, as you say, very subject to opinion.

Being a real "science geek" (also with degree level chemistry) at heart myself I hear and understand everything you're saying about basic knowledge.
However, being in the education biz myself tends to steer me away from giving particular importance to my own skill set and knowledge base.


Indeed, to quote your own words "no adult in the modern world should be considered educated without a grasp of some plurality of some basic knowledge set.", which I agree with but for the sake of argument we could go with the knowledge set allowing us to create works of art or music.

Neither of these knowledge sets requires the formula for water, but I don't think we can eliminate some of our great creative individuals from the voting process just yet!

Having said that, if you have a look at www.senseaboutscience.org.uk you'll see a wonderful teardown of some science "facts" put forward by some our of leading "celebrities"


I certainly grant that most visitors to this site will also veer towards the science geekdom side of things so perhaps your argument stands in many cases, but I still think not all.  Perhaps I'm just playing devil's advocate!

So there! *puts away his own soapbox for the time being*

Apologies to anyone I've bored with my own rant :)
Oh, we're having fun now! >;-) Good responses, every one.

"also with degree level chemistry" -- whoops! I never said that. In fact, I've had only 2 chem classes, and that's generous - one was junior high and the other high school, and I didn't excel at either. I'm self-taught over the last 4 years or so, with some help from a PhD friend or two and a lot of journal articles....

I agree fully about not eating too much of one's own dog food. My educational and work background is management (MBA) and IT, so my criteria also include basic computer & Internet skills, balancing a checkbook, a rudimentary grasp of economics ("supply and demand", as Father Guido Sarducci's 5-minute University had it), and how interest works.

People ought to have some clue about atoms, electricity, magnetism, light/EM radiation, the Big Bang, stars, and the universe. Ditto nutrition, what a liver's for, vitamins (esp. folic acid), and first aid. Ditto basic literacy, numeracy, and communication skills. Ditto basic geography, history, political science, philosophy, literature, art, and music.

I'm also a big fan of ideas like: everyone should learn to speak another language, play a musical instrument, (try to) get good at a sport, travel to foreign countries, hike/camp in the wilderness, go sailing out of sight of land, summit a mountain, be able to cook one good meal, etc.

OK - I've now fully digressed into a complete rant about how the entire human race should conduct its affairs. So - I'll see your apology, and raise you. ;-) I realize this is not the forum for my opinions on this -- I'll take it offline henceforth.

LOL...I'm calling "stalemate" on this one since we've both gone a touch off-topic, but it's been fun for me too. :)
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