Sciencemadness Discussion Board - Making Sodium Hydroxide(Lye)

This won't work; calcium hydroxide is sparingly soluble in water whereas sodium hydroxide is very soluble. I've read somewhere that sodium bicarbonate(?) can be heated with calcium hydroxide in a furnace to make small amounts of sodium hydroxide. Sounds like a flimsy, messy way of obtaining lye.

Depending on where you live, you may be able to get relatively pure lye OTC. It's rather expensive, though. It can also be sourced from the internet very easily.

Tank

Are there any other ways that are easy enough to do that give an anywhere decent yield?

I can't seem to find the pellets anywhere.

I have some oven cleaner with it and I have tried to boil it down to obtain the lye
Only problem is that it has some sort of foaming agent in it.

Manifest - 7-12-2012 at 18:12

This won't work; sodium chloride (in solution) will be your major yield unfortunately. I've read somewhere that sodium bicarbonate(?) can be heated with calcium hydroxide in a furnace to make small amounts of sodium hydroxide. Sounds like a flimsy, messy way of obtaining lye.

Depending on where you live, you may be able to get relatively pure lye OTC. It's rather expensive, though. It can also be sourced from the internet very easily.

Tank

Edited for tired thinking and typing..

[Edited on 12-8-2012 by m1tanker78]

Was your first point not also valid?
Calcium Hydroxide has a solubility of 0.066 g/100 mL at 100C
So, therefore I cannot react it with sodium chloride?

On your other point, could I not make a concentrated solution of the calcium hydroxide(if possible) and then react the salt with that?
Then filter it.
Only problem is Calcium Chloride.

plante1999 - 7-12-2012 at 18:18

It doesn't work like that. Calcium chloride is too soluble for this reaction to happen, reaction of sodium (bi)carbonate with calcium hydroxide make calcium carbonate, which is a lot less soluble than the calcium hydroxide, favoring the reaction.

m1tanker78 - 7-12-2012 at 18:22

My local Lowe's started stocking 'Roebic' brand drain cleaner. There's a big note on the label that says "100% pure lye." It's about $16 US dollars for 2 pounds but it suits my needs since I don't use much of it. Most other drain cleaners contain nitrates and aluminum bits so they're useless for most lye experiments and preparative chemistry.

There's a liquid drain cleaner at one of the local dollar stores that contains a mixture of lye, bleach (I think), and a thickener. I use this stuff sometimes when the latter two won't interfere with the reaction or contaminate the final product.

Believe it or not, I've actually reacted sodium metal with water in the past when I needed some pure lye water. Now that I can buy pure (solid) lye locally, I don't do that anymore.

Regarding your proposed method: If it were the other way around, this would work nicely. In other words, if you combine aqueous calcium chloride with aqueous sodium hydroxide, calcium hydroxide will precipitate. Unfortunately, it doesn't work the other way around.

Tank

Manifest - 7-12-2012 at 18:27

My local Lowe's started stocking 'Roebic' brand drain cleaner. There's a big note on the label that says "100% pure lye." It's about $16 US dollars for 2 pounds but it suits my needs since I don't use much of it. Most other drain cleaners contain nitrates and aluminum bits so they're useless for most lye experiments and preparative chemistry.

There's a liquid drain cleaner at one of the local dollar stores that contains a mixture of lye, bleach (I think), and a thickener. I use this stuff sometimes when the latter two won't interfere with the reaction or contaminate the final product.

Believe it or not, I've actually reacted sodium metal with water in the past when I needed some pure lye water. Now that I can buy pure (solid) lye locally, I don't do that anymore.

It's too bad that I live in the UK.
How on Earth have you had Sodium lying around but not Lye? :?
I guess I'll just have to keep looking then.

Thanks for replying

m1tanker78 - 7-12-2012 at 18:36

How on Earth have you had Sodium lying around but not Lye? :?

Ironic but I acquired a fair amount of it while experimenting with electrolysis of fused sodium chloride. Scout around for lye and consult the MSDS because labels can be quite misleading or vague.

Good luck,

Tank

elementcollector1 - 7-12-2012 at 21:21

Apparatus: A large flowerpot with no hole in the bottom, as well as a smaller flowerpot inside this (also with no hole in the bottom), preferably glued together as well as possible.
Power source(s): Car battery or car battery charger, computer power supply (will need to mess with, not recommended). Any given Duracell battery will not be sufficient power to overcome the sheer voltage drop between the two pots.
Outer liquid: NaCl, saturated solution
Inner liquid: Tap water (sounds crazy, but it works)
Anode: Carbon (obtained from the inside of a 6V or lantern battery)
Cathode: Preferably nickel, gold or something else that is not amphoteric. Steel and stainless steel could work as well, but they may mess with the product (though stainless would have to be etched first.)

Set all that up, run it, and after a long while, you'll collect a fairly pure NaOH solution out of your inner pot. Boil this down to get solid NaOH, but do it in a steel container (molten NaOH can dissolve glass and your face, at the same time!)

I hope that helped.

[Edited on 8-12-2012 by elementcollector1]

cyanureeves - 7-12-2012 at 21:45

Manifest i know you need sodium hydroxide but the way tanker also got sodium metal was by sticking a welding machine annode and cathode into molten sodium hydroxide and zapping the lye. i tried it and it worked great.elementcollector1 i read your method somewhere else and the flower pots are clay pots arent they?i'm not sure if i even saw pictures of this set up and one of the problems encountered was partial disintergration of the clay pot but i maybe dreamin or something. our lowes also carries the roebic sodium hydroxide after a couple of years absent from the shelves also an ace hardware opened up here just a few blocks away. ace hardware carries xylene.toluene and clear ammonia all of which i bought immediately and finally made my hydrazine sulfate.

elementcollector1 - 7-12-2012 at 21:54

Quote: Originally posted by cyanureeves

Manifest i know you need sodium hydroxide but the way tanker also got sodium metal was by sticking a welding machine annode and cathode into molten sodium hydroxide and zapping the lye. i tried it and it worked great.elementcollector1 i read your method somewhere else and the flower pots are clay pots arent they?i'm not sure if i even saw pictures of this set up and one of the problems encountered was partial disintergration of the clay pot but i maybe dreamin or something. our lowes also carries the roebic sodium hydroxide after a couple of years absent from the shelves also an ace hardware opened up here just a few blocks away. ace hardware carries xylene.toluene and clear ammonia all of which i bought immediately and finally made my hydrazine sulfate.

I would imagine it does degrade, as the ceramic is porous to water (which is what allows ion transfer in the first place).
I would love to have some toluene right now... Ah well.

Random - 8-12-2012 at 05:45

I make NaOH that can comfortably dissolve aluminium with baking soda and ca(OH)2 solid large excess, add water, mix and leave for some time, then I filter everything and store it

I am not sure what concentration it is though.

Lambda-Eyde - 8-12-2012 at 05:50

Then why don't you find out? Dilute it, do some titrations and analyze it for Ca impurities. In my eyes it's worthless for proper chemistry if you don't know the concentration.

Manifest - 8-12-2012 at 07:16

I make NaOH that can comfortably dissolve aluminium with baking soda and ca(OH)2 solid large excess, add water, mix and leave for some time, then I filter everything and store it

I am not sure what concentration it is though.

I don't understand what you mean.

You can dissolve aluminium and baking soda with the NaOH?

Manifest - 8-12-2012 at 07:19

Quote: Originally posted by cyanureeves

Lol, using Lye to make Lye. I think you mean Sodium Chloride.

It would be much better to use something like Sodium Chlorate that has a low melting point.

Also, why use a welder? Why not a battery charger with carbon or copper electrodes it's much easier.

Manifest - 8-12-2012 at 07:24

Also, electrolysis of molten anything(especially Alkali metals)
is incredibly dangerous.

When the sodium forms it will react and then splash the sodium chlorate everywhere.

m1tanker78 - 8-12-2012 at 09:52

Manifest, you're correct. Electrolysis of molten salts is very dangerous. Lye in particular has a habit of spitting profusely in my experience. A properly built Castner cell can yield a good amount of metal and is less dangerous than simply sticking carbons in the melt.

Forget about sodium chlorate. It decomposes at MP and releases oxygen. I haven't tried it but can surmise that it would make lye electrolysis look like kids play. It reforms sodium chloride anyway..

The thread got off topic a bit but I guess it's ok because the original question was addressed.

There are a lot of UK members here and surely one of them can chime in and help you source some lye.

Tank

Manifest - 8-12-2012 at 14:00

Manifest, you're correct. Electrolysis of molten salts is very dangerous. Lye in particular has a habit of spitting profusely in my experience. A properly built Castner cell can yield a good amount of metal and is less dangerous than simply sticking carbons in the melt.

Forget about sodium chlorate. It decomposes at MP and releases oxygen. I haven't tried it but can surmise that it would make lye electrolysis look like kids play. It reforms sodium chloride anyway..

The thread got off topic a bit but I guess it's ok because the original question was addressed.

There are a lot of UK members here and surely one of them can chime in and help you source some lye.

Tank

Oh stop it you!
I'd imagine another problem would be the Sodium melting straight after it forms. No?
97.72 °C

And Hexavalent PM'd me telling me where to get it, so he deserves a cookie.

Is it hard in Texas to source this stuff or to buy glassware
Apparently it's illegal to own a beaker there.

blogfast25 - 8-12-2012 at 14:11

It's too bad that I live in the UK.
How on Earth have you had Sodium lying around but not Lye? :?
I guess I'll just have to keep looking then.

Thanks for replying

You can buy unadulterated NaOH from most hardware stores in the UK. Cheap as chips too! Pure NaOH is hard to make, don't bother, just buy!

Hexavalent - 8-12-2012 at 14:14

And Hexavalent PM'd me telling me where to get it, so he deserves a cookie.

Cheers. Chocolate Hob-Nobs are my favourite

Is it hard in Texas to source this stuff or to buy glassware
Apparently it's illegal to own a beaker there.

Yes, unless you have a permit IIRC.

m1tanker78 - 8-12-2012 at 14:46

I remember researching Texas laws a while back because I wanted to start ordering real glassware. I got tired of doing soda bottle chemistry and I'll bet cyanureeves can testify as well. Apparently, lab glassware must be registered. Authorities are real trigger-happy about this type of thing around here. There isn't a single lab supply outlet or store anywhere around here. There are some further upstate but they thumb their noses at the lil-ol-mes. Thank goodness for ebay!

Sheesh... I better revisit those regs.

Quote:

And Hexavalent PM'd me telling me where to get it, so he deserves a cookie.

See, now, I told you so!

Tank

Manifest - 8-12-2012 at 15:35

I remember researching Texas laws a while back because I wanted to start ordering real glassware. I got tired of doing soda bottle chemistry and I'll bet cyanureeves can testify as well. Apparently, lab glassware must be registered. Authorities are real trigger-happy about this type of thing around here. There isn't a single lab supply outlet or store anywhere around here. There are some further upstate but they thumb their noses at the lil-ol-mes. Thank goodness for ebay!

Sheesh... I better revisit those regs.

Quote:

And Hexavalent PM'd me telling me where to get it, so he deserves a cookie.

See, now, I told you so!

Tank

Oh god, imagine customs opened your package from ebay.
Do you not shit yourself everytime you order a beaker from ebay?
It's so stupid that over the Meth problem they go as far as to prohibit glassware or a hobby.

AndersHoveland - 9-12-2012 at 05:29

Industrially, before modern electrolysis was used, the route to NaOH involved a long series of steps:

1. reaction of sulfuric acid with sodium chloride
2. reduction of sodium sulfate with coal
3 reaction of sodium sulfide with calcium carbonate (CaS was completely insoluble)
4. reaction of sodium carbonate with slaked lime (itself made by roasting limestone at high temperatures) in water, and precipitating out the waste CaCO3 to leave NaOH in solution.

This involved the Leblanc process. Later the Solvay process supplanted it, before itself finally becoming obsolete when cheap electricity became available for electrolysis of salt water.

[Edited on 9-12-2012 by AndersHoveland]

m1tanker78 - 9-12-2012 at 07:24

It's so stupid that over the Meth problem they go as far as to prohibit glassware or a hobby.

It isn't prohibited. It is, however, heavily regulated. I don't like the idea of being on any blacklist but at the same time, I have nothing to hide. I personally hate this type of encroachment on my liberty and privacy. In reality, if they REALLY want to screw you, the authorities can stick you with an 'intent to manufacture' charge. I have several friends in LE from local on up to federal. For the most part, they say that as long as I'm not doing anything 'illegal', the worst that can happen is that my glassware can be confiscated. I suppose it would be a good idea to register myself (shudder) to help my cause if they ever did come poking around. Still, it sucks to be dragged through the mud when you've done nothing wrong.

If any fellow Texan hobby chemists are interested, here it is right from the horse's mouth:

http://www.txdps.state.tx.us/RegulatoryServices/narcotics/na...

Ironically, I've seen reports of megalabs in Mexico that are mass-producing Meth. Their precursors are shipped by cargo ships [mostly] from China. The drug runners are becoming more and more brazen at the U.S./Mex border so if the laws of economics still hold up, well, I won't get into that.

At least there's no application fee for the permit. Sheeez! :mad:

Tank

Manifest - 9-12-2012 at 11:48

It's so stupid that over the Meth problem they go as far as to prohibit glassware or a hobby.

Tank

Do you watch Breaking Bad?

Anyway, for the record I've thought of another idea I don't think anyone has suggested yet.

Heating baking soda to make sodium carbonate and reacting this with the calcium hydroxide.

Yields sodium hydroxide and calcium carbonate.

Calcium carbonate is not very soluble in water whereas sodium hydroxide is.

Also, sodium carbonate could be recycled

Hexavalent - 9-12-2012 at 11:55

This would work in theory, but would again be limited by the very low solubility of calcium hydroxide in water.

Again, what is wrong with buying it from stores (it is very cheap and often very pure) or online? It is much easier to buy it than to make it, unless you are purely doing it to explore the science or as a 'proof of concept' experiment.

Manifest - 9-12-2012 at 12:12

Quote: Originally posted by Hexavalent

This would work in theory, but would again be limited by the very low solubility of calcium hydroxide in water.

Again, what is wrong with buying it from stores (it is very cheap and often very pure) or online? It is much easier to buy it than to make it, unless you are purely doing it to explore the science or as a 'proof of concept' experiment.

Would you need to add water? You could do it dry...

I said for the record. I have already bought some from Boots(thank you!)

Also, there is something just fucking awesome about making things yourself and as you said exploring the science.

Hexavalent - 9-12-2012 at 12:24

I'll drink to that

Glad you found your NaOH in Boots.

I see, be you proposing heating stoichiometric quantities of calcium hydroxide and sodium carbonate in a vessel, and then dumping the contents into water? That would make sense, and I rather think it would work. I've prepared ammonia gas previously by dry heating NH₄Cl with with Ca(OH)₂...perhaps the same concept works here too? I might try that sometime if I have spare time in the lab, and I shall report back.

elementcollector1 - 9-12-2012 at 14:01

The above never occurred to me... it would certainly be an interesting method of preparation.
Now, how do we go about getting potassium carbonate, and thus make KOH?

blogfast25 - 10-12-2012 at 13:14

Quote: Originally posted by elementcollector1

The above never occurred to me... it would certainly be an interesting method of preparation.
Now, how do we go about getting potassium carbonate, and thus make KOH?

Potassium carbonate is historically known as 'potash' (from which also the name 'potassium' is derived). 'Potash' is literally the leachate obtained from leaching wood ash with hot water (in pots). Filtering and evaporating the filtrate yields a poor quality K2CO3. Yield is small and varies.

Better K2CO3 is obtained from calcining OTC Cream Of Tartar. That grade is known as 'pearl potash' because it is superior to potash.

There are threads on all that here.

And yes:

Ca(OH)2(s) + K2CO3(aq) === > CaCO3(s) + 2 KOH(aq)

... works.

[Edited on 10-12-2012 by blogfast25]

Random - 14-1-2013 at 11:35

I don't understand what you mean.

You can dissolve aluminium and baking soda with the NaOH?

No...I make my own NaOH solution by mixing a large excess of Ca(OH)2(s) with baking soda and add some water then filter.

I am not sure which concentration the solution is but it can dissolve aluminium easily.

Manifest - 15-1-2013 at 14:14