Sodium Sulfide

[Al Koholic]

Over the course of the last few weeks I have been pondering a better way to make picramic acid from TNP. As part of this process I have spent a decent amount of time in the university library finding journal articles and whatnot.

My main point here is that picramic acid synthesis seems to be a fairly easy process but I believe that the method of producing it utilizing a sodium sulfide solution prepared from S and NaOH may be less than adequate...at least for my liking.

I found out that there are a few other methods for producing Na2S besides making the nonahydrate in solution from S and NaOH which I fear is very inefficient. For one, reacting sulfur and sodium metal in liquid ammonia is a method which has been cited as being in the Handbook for Preparative Inorganic Chemistry. I have not viewed this method and I'm not sure how viable it is to be conducting reactions in liquid ammonia.

The other method is the reduction of Na2SO4 with plain ole carbon.
Na2SO4 + 4C --> Na2S + 4CO

Some other examples:

3Na2SO4 + 4CH4 --> 3Na2S + 4CO + 8H2O
Na2SO4 + 4CO --> Na2S +4CO2
Na2SO4 + 4H2 --> Na2S + 4H2O

These reactions take place at temperatures ranging from 700 to 1000 C. K salts can be substituted for the Na salts as well if K2S is desired.

The carbon method is the one which interests me the most. I am thinking of constructing a reaction vessel from some sort of high temp resistant material. Im thinking either a glazed ceramic container or a metal (iron/steel) one. I will base that decision on whether Na2S in its anhydrous crystal state is corrosive to metal or not.

I am thinking a metal tube about 1 or 2 inches in diameter with a cap at one end will be filled for 10% of its length with an intimate powder of C prepared from sugar/h2so4 and Na2SO4. This will be heated with a propane flame and the evolution of gas will be monitored by simply holding a flame into the tube to determine if CO2 is being evolved.

I believe if I react 2Na2SO4 + 4C --> Na2S + 4CO, the unreacted Na2SO4 will react with the CO according to Na2SO4 + 4CO --> Na2S + 4CO2.

My questions are:
Will the procedure I have in mind work even if the mixture is exposed to the atmosphere?
Will the Na2S formed attack a steel/iron reaction vessel? Stainless steel?

Edit: I forgot to mention that the reason I'd like to attempt this method is so I can weigh out exact quantities of Na2S and KNOW how much I'm getting in solution before I react with sodium picrate solution. I feel like the other method results in poorer solution which may be the cause for a lot of peoples' ailments when it comes to DDNP synth.

<small>[ January 27, 2003, 11:03 PM: Message edited by: Al Koholic ]</small>

[nbk2000]

Well, if you had sodium metal, then the liquid ammonia reaction would be the simplist.

Na2S is a primary ingredient in the manufacture of mustard gas from ethylene glycol (anti-freeze), since it's used to convert chlorohydrin into thiodiglycol.

While it's still readily available for purchasing, the ability to make it from sodium compounds, carbon, and sulfur, would greatly further the ability of a home experimenter to make mustard without being detected or traced.

From what I've gathered, you don't want to expose the reaction mix to the air because the oxygen will react with the sulfur, forming something that isn't Na2S.

[Al Koholic]

Not exposing this reaction to air is kind of what I was leaning towards as well. I suppose that since my setup could be a fairly long tube (say, 2 meters) with the bottom 1/4 filled with the mixture, CO2 could easily be used to purge the initial air. Once the reaction was going, the evolved CO2 would prevent any influx of air. The cooling down stage could be protected with a CO2 feed the same as the heating up stage.

It's interesting to note that I downloaded a bunch of movies made by a guy who had a "sodium party" with 1 pound of Na bought on EBAY!

I can upload a couple of the better videos to the FTP if anyone wants... But the other day I was on Ebay looking for a heating mantle for 1000 ml rb boiling flasks and I came across someone who in addition to selling a mantle, was offering 1 pb of Na metal! What the hell? So I also did another inquiry and found a miriad of exotic chems for sale on ebay among which was a bottle containing 917 grams of iodine crystals. WOW.

Anyway back on topic here, I'm also under the impression now that Na2S will be highly reactive to a metal reaction vessel at the temps required for the reaction. Im at a loss as to what else I could use as a reaction vessel considering that the mix has to be sealed from air most likely. Originally I thought maybe it could be heated in a ceramic bowl...

Al

[THe_rEaL_dEaL]

If the Na₂S is reactive with the metal why not use a ceramic pipe having a coupling of teflon spray coated metal pipe connecting to a threaded teflon coated end cap on each end.

I have a feeling that the teflon would be scratched off on the thread area, leaving the metal open to possible reaction. Put plumbers tape over the thread to inhibit reactant contact.

Would this reaction work more efficiently with high or low pressure?
Can PTFE take 1000K temps? (I have a feeling yes because they use it on the space shuttles.)

I'd be interested to see how well your ideas/designs work. Keep us Posted

[Polverone]

No, PTFE can't survive 1000 degrees Celsius. It breaks down somewhere in the 400 degree range, IIRC. I have obtained sodium sulfide by accident when making sodium cyanide with charcoal that had been incompletely cooked; organic compounds in the wood provided the sulfur, and the high-temperature reduction ensured that it became sulfide.

I would just try heating your sodium sulfate and carbon together in ordinary steel containers first. You won't know how well steel resists until you try it. And I don't think you need to take heroic measures to exclude air. Do like I've done for cyanide production: get two steel food cans, one larger in diameter than the other. Fill the smaller one with your mixture and invert the larger one over it, like so (pardon lousy ASCII art):

xxxxxx
xo..ox
xo..ox
xo..ox
.oooo.

Purging with CO2 should be quite unnecessary if you use an excess of carbon. The atmosphere within the setup will soon become mostly CO2/CO/N2 of its own accord. For that matter, using carbon prepared from H2SO4 and sugar is extremely inefficient and unnecessary. Powdered charcoal (not charcoal briquettes) will work well and cost a lot less.

In any case, you are right to suspect the production of Na2S from sulfur and NaOH in solution. It mostly produces sodium polysulfides and thiosulfate. It's a reducing mixture, sure, but it's not a very clean or easy to standardize one.

[Al Koholic]

Polverone, thanks for the idea with the cans. I also am wondering what the temperature was for your sodium cyanide experiment where you said you might have gotten some Na2S.

Al

[Polverone]

The cans were heated in a wood fire and they were a bright orange at their highest heat. I'm not sure what temperature that corresponds to. It was hot enough that the sodium cyanide was evaporating; when I took the cans off of the fire and let them cool, the top can was stuck to the bottom one by glassy deposits.

[Al Koholic]

I do have to ask before I make my own Na2SO4...
What, if any, are the common comercial sources for this substance?

[Mr Cool]

I don't know, but ammonium sulphate is a common fertilser, and sodium hydroxide is a common drain cleaner. Mix the two, and you'll get sodium sulphate and ammonia.

[Al Nobel]

If you don´t want to produce by yourself you can order it from omikron online.de (but I don´t know if they sell chemicals to the USA).

[nbk2000]

Here's a current source in the US.

<a href="http://www.photoformulary.com/BULK-PRC-S2-Send.htm" target="_blank">http://www.photoformulary.com/BULK-PRC-S2-Send.htm</a>

[Al Koholic]

Well, just a little status update here...

I have just finished making what should be (once its dry) 140g of Na2SO4. I reacted 2NaHCO3 + H2SO4 --&gt; Na2SO4 + 2H2O + 2CO2.
Cheap and easy.

For a while there I was going to do the whole H2SO4 + NaCl heated to evolve the HCl gas and leave Na2SO4 but that just creates mulitple problems (ie: I have to go to the lab to do it b/c I have no fume hood in my room).

Then I thought 2NaOH + H2SO4...realized that would get expensive quick.

I don't know why I didn't think of the bicarb till yesterday...just managed to stay out of the limelight.

In the coming days when I can find a spare moment I'll be producing charcoal by sealing a container of wood chips and cooking it in my grill for a while.

[Al Koholic]

Ok, a little break in school occured (spring break which for me is only today and tomorrow). I came home but forgot to bring my scale with me so please understand that this update is a *bit* less than quantitative.

Anyway, I found a nice tin that I filled with oak chunks, then filled the spaces with sawdust of unknown wood type. I placed the tin in a fire with some holes in the lid and obtained a good amount of charcoal.

I mixed what looked like and felt like around 3 grams of the charcoal (this stuff was almost airfloat so it was quite a bit volume-wise). I then added about 8 grams of Na2SO4. I mixed it all up and it appeared very much still like charcoal with some white specks. I placed this into a tin can and made a makeshift tripod out of a coat hanger. I placed a mini bunsen burner under the can and turned on the propane! The can was also capped with another can like Polverone suggested. I heated it like crazy to red heat for a while. When I looked in expecting to see a melt, it was still just looking like the original mix. Anyway, I scraped some of the stuff from the bottom and placed it in some water. I obtained a deeeeeeep black solution that when diluted is a steely blue color. This was not a result of the carbon being contaminated as I checked by placing some in water and not getting this effect. The solution also had a fairly strong rotten egg odor and maybe some SOx. The solution was filtered and I added about 10 ml of vinegar...nothing happened. Ill try adding some conc. HCl tomorrow.

Next, I figured I'd try a diffrent ratio this time to try and obtain a melt. I added 3 heaping teaspoons (like 10 or 20 grams) of Na2SO4. I added a small amount of the carbon dust...maybe 2 level teaspoons all together. I heated this one even more strongly with double propane torch blasting. Heating commenced for about 15 minutes with a cap, then I heated it directly under and with a flame from one torch right on the mixture as it had become a hard solid mass at this point. I ceased heating and let it cool. I scraped the inside of the can and broke up the melt into chunks. Upon removing the chunks it was found that they were red/brown and porous. There was also still a considerable amount of white Na2SO4 solid. I dissolved the chunks in water and got an incredible solution...jet black. I filtered it and poured it out into a tray to dry overnight and it appears deep green/blue when spread out in the tray. I also added some chunks to some denatured alcohol, filtered it and noted that it has a lightish green/blue color now but nothing like the water. Next I added maybe 15ml of hot water to the can to swirl it around a bit and clean it. The bottom was eaten away in about 9 seconds. A hole just formed and the solution ran out into the sink. I continued heavily dosing the can with very hot water from my tap and for about 2 minutes, deep black solution flowed out through the 3 cm wide hole in the bottom. Anyway...thats what happened tonight. By tomorrow the stuff should be dry so it can be observed a little better.

I don't know what this is though. Na2S is supposed to be white and colorless in solution. The smell and corrosiveness are in line with Na2S though. As is the differential solubility in water and alcohol. Ill have to add some conc HCl to it tomorrow to see how much, if any H2S is liberated. You'll also be interested to note an additional experiment I performed with it.

I heated some Na2SO4 on a teaspoon over a propane torch. The spoon was stainless and was glowing bright red/orange at its peak temperature. The Na2SO4 melted kinda strangely and bubbled a tiny bit, then seemed to just melt into a yellow mass. This mass when placed in water also produced the same solution I obtained from the other experiments. Is it possible to make Na2S by simply heating Na2SO4?! Anyway, more experimentation is DEFINETLY in order for tomorrow.

[megalomania]

You can also make sodium sulfate by heating a solution of sodium bicarbonate (baking soda) and magnesium sulfate (Epsom salts). This precipitates magnesium carbonate and leaves sodium sulfate in solution. I have been making a lot of this as waste while preparing magnesium compounds and as of yet I have found no use for it.

I have a little note somewhere around here that says "find out if sodium sulfate decomposes into sulfur trioxide when heated" which I wrote a few weeks ago after reading something that indicated this may happen. This is not valid conformation of course, I am still looking. My desire is to convert sodium sulfate into sulfur or sulfuric acid, but that is for another thread.

[Mr Cool]

NaHSO₄ will:

2 NaHSO₄ --300*C--&gt; Na₂S₂O₇ + H₂O

Na₂S₂O₇ --350*C--&gt; Na₂SO₄ + SO₃

Also

NaHSO₄ decomposes into Na₂SO₄ and H₂SO₄ by extraction with 80% EtOH. The former is insoluble in the liquid and the latter goes into solution.

(all originally posted by rikkitikkitavi)

The later method might be easier if you want H₂SO₄, not SO₃.
So you need something to react your Na₂SO₄ with first to make NaHSO₄. I suspect HCl could be used, it is cheap and readily available and it is a strong acid. But at the higher temperatures used you might also get some HCl coming off, even though HCl is much more acidic than HSO₄^- so normally the equilibrium is nearer to NaHSO₄ and NaCl:

NaHSO₄ + NaCl &lt;=-&gt; Na₂SO₄ + HCl

[Tosh]

How about plain old 2NaOH + H2S -&gt; Na2S + 2H2O, sure H2S is pretty lethal but you dont have to be anywhere near the reaction site.

Btw, nice forum.

<small>[ March 12, 2003, 02:22 PM: Message edited by: Tosh ]</small>

[megalomania]

From what I know about this reaction using calcium sulfate as the starting material the reaction is not very efficient. I assume the same reaction holds true for sodium sulfate with respect to the chemicals produced. The reaction products are:
CaSO4 + C --&gt; CaS (55%) + CaSO4 + CaSO3 + CaCO3

With calcium only calcium sulfide is soluble to any degree, but with sodium all the compounds are soluble. You may want to use alcohol as the solvent because neither sodium sulfite, sulfate, or carbonate is soluble, but sodium sulfide is.

The process of converting sodium sulfate to sulfide is described in considerable detail as the old “soda ash” method for making sodium carbonate. If your research, Al Koholic, has not found this I suggest try searching for it.

[Al Koholic]

Tosh, I know about that reaction, its just that I would rather not set up an H2S generator if I can avoid it.

Mega, I have not researched the "soda ash" method. I'll have a looksie tomorrow when I'm in the library. I read in a book called something like Preparative Industrial Inorganic Chemistry or something like that about the Na2SO4 + C method. It states that there are 3 different types of furnaces used for the reaction but it is mostly a qualitative source, no real detailed procedure. It was an attractive route to me because of the ease of obtaining the materials and what SHOULD be a fairly easy procedure. However, judging from my experiences this weekend, it will require some more investigation.

I'll see if I can locate a detailed procedure sometime tomorrow and give it a look.

[Tosh]

</font><blockquote><font size="1" face="Verdana, Arial, Helvetica">quote:</font><hr /><font size="2" face="Verdana, Arial, Helvetica"> Tosh, I know about that reaction, its just that I would rather not set up an H2S generator if I can avoid it. </font><hr /></blockquote><font size="2" face="Verdana, Arial, Helvetica">Yes, ofcourse i didnt mean to imply that you didnt (basic chemistry knowledge seen seems to be quit high on this forum :cool: ) i just suggested it because seems to be one of the few ways of making Na2S that will yeild a reasoble pure and consistent product! imho the other synths though interesting, will yeild a lesser quality product and will be difficult to keep consistent and or time consuming to purify.

[Al Koholic]

I agree with you on that point. While it is not hard to filter out the insoluble waste from the reaction I have been working on, it will prove more time consuming and expensive to separate the soluble material from the Na2S. If and when this reaction gets figured out, I'll have to first do a water extraction, then an alcohol extraction to separate out the Na2S only. All this while the product is likely decomposing...

Im wary about a first step alcohol extraction because I fear some organic residues contaminating the product without a water step first. More and more, this is sounding like an H2S generator might not be such a terrible idea :) hehehe.

[Tosh]

BTW if you dont want to make it there's a easy of obtaining the stuff. People who make wine themselves use Na2S as a preservative, i just found one who will sell me 1kg for 5 euro's :D ! I assume prices in america will be similar (wich means $5 for a kg) :cool: ! Do a search on google on wine making and you should be able to find one.

EDIT: Dammit it would appear that the wine guy i was talking to over the phone meant NaS2O5, dont you hate it when you have to deal with people who know nothing about chemistry <img border="0" title="" alt="[Frown]" src="frown.gif" />

<small>[ March 16, 2003, 05:55 AM: Message edited by: Tosh ]</small>