Sciencemadness Discussion Board

Lye Drain Cleaner

FloridaAlchemist - 20-8-2006 at 08:24

I have not yet tried to separate the ingredients but some of the lye drain cleaners contain only two chemicals : solid sodium hydroxide and sodium nitrate no aluminum shavings.
Anyone ever experimented with this or have any ideas on how to separate them? Both chemicals would be very useful in the hobby lab.
Maybe fractional crystallization of the sodium nitrate then evaporation to obtain the solid sodium hydroxide.

YT2095 - 20-8-2006 at 09:05

if you know the proportions of each, you could add potassium hydroxide, leaving KNO3 and NaOH, the advantage being that KNO3 is much less soluble than the sodium version and would crystalise out a little cleaner leaving a better margin.

evaporate your NaOH fast though! (heating is best) as prolonged exposure to atmosphere will leave you with Sodium Carbonate instead :(

Cesium Fluoride - 20-8-2006 at 09:11

Long time ago, I had a mix of NaCl, NaNO3, and NaOH. I fractionally crystallized out the NaCl, but concluded that the solubilities of NaNO3 and NaOH were too similar for fractional crystallization. My plan was to try glycerin (never tried it). Sodium hydroxide is "very soluble in water, alcohol, and glycerin" whereas sodium nitrate is "very slightly soluble" in glycerin. Evaporating glycerin may take a while.

YT2095 - 20-8-2006 at 09:15

NaOH in alc is pointless, you`ll ruin both.

Cesium Fluoride - 20-8-2006 at 09:17

I suggested glycerin not alcohol.

YT2095 - 20-8-2006 at 09:19

Glycerine is also an alcohol, 1,2,3 propantriOL

thalium - 20-8-2006 at 09:23

If you find "Mr. Muscolo" drain cleaner it contains 100% NaOH. And the little Al pieces in other brands can be saved and used. On many products the proportions are not mentioned :(

Cesium Fluoride - 20-8-2006 at 09:23

Would NaOH react with glycerine? NaOH is used in saponification of fat and in this reaction glycerine is produced as a by-product. I've never heard of excess NaOH destroying the glycerine, but I may be missing something.

Edit: And YT, ethanol used to be used to purify KOH so the reaction to form the acetate isn't too problematic. I don't understand why ethanol will destroy NaOH?

"In order to purify the commercial substance [caustic potash], it may be dissolved in pure alcohol, the insoluble matters allowed to deposit, and the clear solution boiled to dryness in a silver basin. By this method it may be obtained free from sulphate and alumina, but it always contains traces of potassium chloride, potassium carbonate, and potassium acetate, which latter substance is formed by the action of caustic potash on alcohol."

[Edited on 20-8-2006 by Cesium Fluoride]

YT2095 - 20-8-2006 at 09:52

it`s an interesting point about the Glycerol and soap manu, Im`not entirely certain about adding it out of soln though ie/ directly to the prills or crystals, also have you ever tried to evaporate glycerol!?
it`s more fun watching socks dry ;)

ethanol and dry sodium hydroxide makes sodium ethoxide IIRC, same would work with the Potassium too.

Cesium Fluoride - 20-8-2006 at 09:55

That's sodium metal and ethanol that makes the ethoxide. And you're right the glycerol idea wouldn't work too well as by that time you'd have mostly the carbonate. I guess you could try boiling it.

thalium - 20-8-2006 at 09:58

Glycerine is obtained from hydorlisis of fat, in alkaline solution, the reaction is not reversible. Example:
CH2-O-CO-(CH2)14-CH3
|
CH-O-CO-(CH2)16-CH3 + 3NaOH ------> glycerine + C16H31O2Na + C18H35O2Na + C18H33O2Na
|
CH2-O-CO-(CH2)7-CH=CH-(CH2)7-CH3
Soaps are salts of fat acids and are obtained by alkaline hydrolisis of fats.

not_important - 20-8-2006 at 10:06

NaOH (and KOH) are soluble in the smaller alcohols MeOH > EtOH > (iPr, glcerine, ethylene glycol - not sure of the order of those three).

The basic idea is good. Alcohols containing a strong base and exposed to oxygen/air undergo some oxidation, it's not too fast though.

There is a potential problem when there is a large amount of another salt. There is an equlibrium set up NaOH + ROH <=> NaOR + HOH, the left side being the favored. But another salt can pull water into a brine, making that salt damp to an actual aqueous layer. After removing the 2nd salt, it might be best to add a little water to the lye/alcohol layer.

Glycerol isn't practical in that it isn't going to evaporate very fast. Heating it much is a bad idea. Slow evaporation in the air will give you carbonate and a little chloride and sulfate rather than the hydroxide, CO2 is always waiting to steal your hydroxide.

Strong hydroxide, or hydroxide+alcohol mixes, chew up glass. You'd need a evaporation rig made out of stainless steel or copper, if copper then consider plating the inside with silver. I suspect you'd want to only evaporate some of the alcohol, cool, and decant it off the solid NaOH so as not to have a monolythic block of lye in the evaporator.

YT2095 - 20-8-2006 at 10:10

actualy, thinking about it, the NaOH only works on certain alcohols, so ETOH may be ok. I could be wrong though (I`m dead tired atm).

as for boiling glycerine, I`ve a feeling even then it would take for ages to evaporate too.

Cesium Fluoride - 20-8-2006 at 10:14

Scrap the heating idea, just realized you'd get almost all acrolein, which is a carcinogen among other things.

[Edited on 20-8-2006 by Cesium Fluoride]

woelen - 20-8-2006 at 12:58

I have done an experiment by adding glycerol to a concentrated solution of NaOH. When you do this, then the liquid becomes very smelly, but not of acrolein. Acrolein has a strong pungent smell, what I obtain is not pungent, just bad (very "organic" smell, like a really bad soap, that's the best description). So, there indeed is some reaction, but I'm not sure what this reaction is. It might also be that glycerol is oxidized by oxygen from the air under such very strongly alkaline conditions.

guy - 20-8-2006 at 13:03

Isn't oxygen oxidation slowed down by base? O2 + 2H2O + 4e- ---> 4OH- ?

Anyway yeah adding hydroxide to glycerin smells bad, not super strong, but like soap-like I agree.

Cesium Fluoride - 20-8-2006 at 14:26

Will NaOH react with anhydrous glycerine though?

The_Davster - 20-8-2006 at 14:39

Alcohols do react with Na/KOH making the alkoxides. Its in equilibrium. Woelen, you may have gotten Na3C3H5O3(glycerol with the H on OH removed and 'replaced' with Na), analogus to an ethoxide, but 3x on the glycerol molecule.

not_important - 20-8-2006 at 19:56

Quote:
Originally posted by woelen
... It might also be that glycerol is oxidized by oxygen from the air under such very strongly alkaline conditions.


You've got it. I made a request over in the translations/references thread for a article regarding the production of oxalic acid during PET recycling with strong NaOH. To get decent yields in a resonable time, they used medium high pressure yto get enough O2 into the mix to oxidize the ethylene glycol fast enough.

But it doesn't take at lot of oxidised stuff to smell, colour the reaction mix strongly, or make it difficult to purify the product.

YT2095 - 21-8-2006 at 00:22

I put some KOH in glycerol last night (after my second post) to see what would happen, at first nothing at all noticable, upon looking again this morning, there is a yellowing of the glycerol around the KOH crystals, the liquid is still viscous like honey, and I can`t be 100% certain but there is almost no detectable smell to it, it will probably need a good stirring.

I also have no idea what this stuff is now or any of it`s properties, my guess would be that the KOH is quite unusable now though.

seriously, I`de stick to my original idea and add KOH to your mixture, making KNO3 and NaOH, both have a better margin of seperation for fractional crystalisation.

Flip - 5-9-2006 at 10:34

I hate to come right out with a request for a brand name, like i'm special or something... well, I am pretty special... can someone PM me with an OTC NaOH source that is viable. I really don't want to overpay for reagent grade.

hodges - 5-9-2006 at 16:29

Well they still sell pure lye on E-Bay I'm pretty sure. I probably use more sodium hydroxide than just about anything else in my experiments. About 3 years ago I bought 3 cans of Red Devil Lye, and when I recently opened my last one I considered buying more from E-Bay. However I decided to pay a bit more and get pure sodium hydroxide from a chemical supplier the next time I need to place an order.

Hodges

not_important - 7-9-2006 at 21:59

I did a bit of emailing and have been told that in the USA the True Value hardware chain carries Rooto products:

This appears to be mostly NaOH with possibly NaCl, from Gibbs cells that doen't use membranes; some NaCl slips past the electrolysis and ends up in the lye. It should work for many applications and seems to be cheaper that the small household lye containers.

http://rootocorp.com/rooto/sewer_line_cleaner2_6lbs.html

http://rootocorp.com/rooto/professional_drain_opener.html


This discussion says that Rooto and Roebic (Lowe's) are 100% NaOH, as of last Spring.

http://boards.bittercreek.com/tool/post/bittercreek/vpost?id...

djrc - 8-9-2006 at 21:27

Quote:
Originally posted by not_important
I did a bit of emailing and have been told that in the USA the True Value hardware chain carries Rooto products:

This appears to be mostly NaOH with possibly NaCl, from Gibbs cells that doen't use membranes; some NaCl slips past the electrolysis and ends up in the lye. It should work for many applications and seems to be cheaper that the small household lye containers.

http://rootocorp.com/rooto/sewer_line_cleaner2_6lbs.html

http://rootocorp.com/rooto/professional_drain_opener.html


This discussion says that Rooto and Roebic (Lowe's) are 100% NaOH, as of last Spring.

http://boards.bittercreek.com/tool/post/bittercreek/vpost?id...


You'll see that they are not 100% lye (the big tub i am sure of)....it's something like 85%....and as for the rooto drain opener....(the powdered kinds)...there are 2 types...one is labeled "100% lye" while the other kind is labeled "lye-based"....you want the "100%"...

[Edited on 9-9-2006 by djrc]

chemkid - 21-6-2007 at 13:38

I got the 100% lye and haven't had any problems (then again i have barely used it) at ace hardware. Anyone have any idea on the REAL purity of this or a way i could find out? Sadly the rooto website 1) does not respond to e-mails 2)does not post the MSDS's for chemicals. ):

[Edited on 21-6-2007 by chemkid]

[Edited on 21-6-2007 by chemkid]

[Edited on 21-6-2007 by chemkid]

S.C. Wack - 21-6-2007 at 14:07

http://ace.infotrac.net/search.asp

12AX7 - 9-10-2007 at 13:02

Quote:
Originally posted by not_important
I did a bit of emailing and have been told that in the USA the True Value hardware chain carries Rooto products:

This appears to be mostly NaOH with possibly NaCl, from Gibbs cells that doen't use membranes; some NaCl slips past the electrolysis and ends up in the lye. It should work for many applications and seems to be cheaper that the small household lye containers.

http://rootocorp.com/rooto/sewer_line_cleaner2_6lbs.html


Update: I purchased a tub of "Rooto Number 2" the other day. On inspection, it appears to contain aluminum spheroids (approx. 1mm diameter) and an unknown needle shaped crystalline substance.

When added to water, it becomes warm, dissolves (the needles dissolve slower) and the aluminum gives off hydrogen. It is of course strongly basic.

Suppose I'll muck around and try to figure out what the impurity is. Fortunately for me I have an induction heater which should be capable of kicking out the aluminum spheres by eddy current repulsion, but this obviously is not an option for the average mad chemist.

Tim

UnintentionalChaos - 9-10-2007 at 16:13

Didn't you peek inside the container before buying it Tim? Or was it sealed up? If you can find "Roebic Crystal Drain Cleaner" it is, as far as I can tell (and according to the side of the canister), pure lye.

Sauron - 9-10-2007 at 16:19

With NaOH you have two problems.

It is hygroscopic.

It absorbs CO2 and turns into carbonate.

So you have to store it properly, with exclusion of air and moisture.

UnintentionalChaos - 9-10-2007 at 16:42

The canisters it comes in prove to be extremely airtight. The canisters off the shelf are bone-dry inside and free-flowing. If you leave some of the contents out for 10 minutes it will start to clump and get damp, and god knows how long it had been sitting on the shelf before I bought it. By the time I get to the very bottom of a container it has been opened enough times to start to clump. I have yet to see a brand of solid lye being sold with a seal, although I can't get rooto products around here so I wouldn't know about that.

I am quite aware of sodium hydroxide's properties. I think I am using my fourth (2 pound?) canister so far.

[Edited on 10-9-07 by UnintentionalChaos]