Sciencemadness Discussion Board

looking for cheapest routes to acid sythesis

Ragnor73 - 11-5-2017 at 11:33

Hello, I am hoping people can shed some light on the most cost effective methods for production of acids including, Nitric, sulfuric and hydrochloric.

I have several projects mostly based around metallic mineral extractions and carbon/graphite/graphene conversions.

I have found some sources for acids but they are all a bit of a hassle in one way or another and relatively expensive.

If there are any fairly strait forward and cost effective methods for production I would be interested to know them .

Ive watched several nurd rage videos on the subject, but it always seams like those methods are kind of costly for the volumes produced.

PirateDocBrown - 11-5-2017 at 11:50

HCl and H2SO4 are usually OTC. I got a gallon of HCl for under $20, and half gallon of H2SO4 for the same.

HNO3 has a ton of good videos on making it. Sodium nitrate fertilizer is one of the cheapest sources of nitrate, I got 4 pounds for under $10, and that is far from as cheap as it gets.

Cost is relative, getting a 2.5 L growler of HNO3 delivered to your door is gonna run you well over $100, these days.

[Edited on 5/11/17 by PirateDocBrown]

clearly_not_atara - 11-5-2017 at 12:16

I think you can distill hydrochloric acid from a mixture of sodium bisulfate and calcium chloride:

NaHSO4 (aq) + CaCl2(aq) >> NaCl(aq) + CaSO4(s) + HCl (g)

If this is not successful it is possible to produce ZnSO4 by dissolving zinc in hot concentrated sodium bisulfate solution:

Zn + 2NaHSO4(aq) + heat >> ZnSO4(aq) + H2 + Na2SO4(aq)
ZnSO4(aq) + cold >> ZnSO4(s)

This reacts with CaCl2 to give zinc chloride hydrate, ZnCl2*2H2O, which decomposes when heated releasing HCl gas.

If CaCl2 is unavailable, ammonium chloride can be made from salt, carbon dioxide and ammonia:
NaCl (aq) + NH3(aq) + CO2 (aq) >> NH4Cl(aq) + NaHCO3(s)
the bicarbonate being removed by exploiting its lower solubility. This makes up the Solvay process. The NH4Cl then reacts with quicklime to give CaCl2:
2NH4Cl + CaO >> CaCl2 + 2NH3 + H2O

It might be possible to make HCl by the direct oxidation of NH4Cl but I'm not exactly clear on how to do this. From 10000 feet it looks like H2O2 over TiO2 is the way to go. Noxious gases may be produced.

H2SO4 is harder. Easy in principle because sodium pyrosulfate decomposes to give SO3, but you do not wanna fuck with that molecule. The hydrolysis of sulfuryl chloride is a little nicer:

SO2 + Cl2 + [catalyst] >> SO2Cl2
SO2Cl2 + 2H2O >> H2SO4 + 2HCl (slow)

Once you have a little H2SO4 you can make more by a reciprocating process:

sulfuric acid + SO3 >> oleum
oleum + H2O >> more sulfuric acid

This "slows down" the exothermic hydration of SO3 enough to make it manageable. It's probably the best way to make large amounts of sulfuric acid.

[Edited on 11-5-2017 by clearly_not_atara]

Melgar - 11-5-2017 at 15:01

The cheapest route for massive quantities would be to set up your own contact process system, burning sulfur and oxidizing that further to SO3, etc. Combine that with a nitrate salt and distill for nitric acid, combine with a chloride salt and distill for hydrochloric acid, etc. You end up with three times your mass of sulfur in H2SO4, with that mass being extracted from water and the atmosphere. Agricultural-grade sulfur is fine for this, and is available in 50-pound bags at least.

If you don't want to go that route, it shouldn't be hard to source sulfuric acid for about $20/gallon and 30%+ HCl for $7/gallon. Calcium nitrate is probably the cheapest easily-obtained nitrate salt, for about $25 for a 50-pound bag, assuming there are agricultural supply stores near you. If you can set up a business with the right sort of credentials to buy that stuff commercially, that would be even cheaper.

If you're interested in the economics of different methods of obtaining sulfuric acid, one gallon of the stuff weights about twice as much as water, about 15 pounds per gallon. At least in the US, if you're buying stuff in bulk, it'll usually come in 50-100 pound bags, or five-gallon buckets, as the largest amounts an individual can purchase, so it's easier to just use pounds and gallons as your units.

clearly_not_atara - 11-5-2017 at 17:15

Actually come to think of it, it should be possible to make zinc sulfate by combining ZnO with SO2 and H2O2 since the pH will not drop too low to stop the reaction between SO2 and H2O2 (which is normally the problem with this method). SO2 is quite easy to make unlike SO3.

It might be possible to then add CaCl2 to the solution directly, filter and distill off HCl, but you should ensure the H2O2 is completely consumed if you're going to do that! You definitely don't want to be surprised by H2O2 in your HCl (H2O2 is stable in hydrochloric acid so it will persist).

edit: ref for the solubilities used in the prep of ZnCl2*nH2O:

https://www.env.nm.gov/wqcc/documents/NMEDExhibit15.pdf

[Edited on 12-5-2017 by clearly_not_atara]

JJay - 11-5-2017 at 18:18

It's possible to make hydrogen chloride by electrolyzing brine and reacting the gases in a combustion tube. You can make nitric acid by ionizing air. It's low yielding and requires a lot of electricity, but the starting materials are free. Sulfuric acid... probably the cheapest way is by burning sulfur and reacting the sulfur dioxide with air over a vanadium pentoxide catalyst. Note that while all of these methods are conceptually simple, none of them are easy in practice.

Dr.Bob - 12-5-2017 at 12:09

If you want cheap, the solution is to buy them from industrial supply houses, you will not be able to make them cheaper than a big factory, the cost of shipping them is more than the cost to make them. But if the overall cost includes shipping, then you might be able to make some from others, like HCl from H2SO4, but ultimately, the cheapest way is to buy them from someone who uses them in bulk. OTC drain cleaner, pool chemicals, muriatic acid for cleaning masonry are all good sources.

Nitric is the hardest to find easily, so that might be the best to make from sulfuric.

Corrosive Joeseph - 12-5-2017 at 14:53

Quote: Originally posted by JJay  
It's possible to make hydrogen chloride by electrolyzing brine and reacting the gases in a combustion tube.
Note that while all of these methods are conceptually simple, none of them are easy in practice.


Really........?
I found this the other day and thought it might be promising


"In the chlor-alkali industry, brine (mixture of sodium chloride and water) solution is electrolyzed producing chlorine (Cl2), sodium hydroxide, and hydrogen (H2):

2 NaCl + 2 H2O → Cl2 + 2 NaOH + H2
The pure chlorine gas can be combined with hydrogen to produce hydrogen chloride in the presence of UV light:

Cl2(g) + H2(g) → 2 HCl(g)
As the reaction is exothermic, the installation is called an HCl oven or HCl burner. The resulting hydrogen chloride gas is absorbed in deionized water, resulting in chemically pure hydrochloric acid. This reaction can give a very pure product, e.g. for use in the food industry."

https://en.wikipedia.org/wiki/Hydrogen_chloride#Production

Hydrochloric acid from salt, water, electricity and daylight........?
Somebody please, shoot this down


/CJ


yobbo II - 12-5-2017 at 15:01


So long as you have an anode and suitable membrane, you are on the pigs back (so to speak).

JJay - 12-5-2017 at 15:07

Quote: Originally posted by Corrosive Joeseph  
Quote: Originally posted by JJay  
It's possible to make hydrogen chloride by electrolyzing brine and reacting the gases in a combustion tube.
Note that while all of these methods are conceptually simple, none of them are easy in practice.


Really........?
I found this the other day and thought it might be promising


"In the chlor-alkali industry, brine (mixture of sodium chloride and water) solution is electrolyzed producing chlorine (Cl2), sodium hydroxide, and hydrogen (H2):

2 NaCl + 2 H2O → Cl2 + 2 NaOH + H2
The pure chlorine gas can be combined with hydrogen to produce hydrogen chloride in the presence of UV light:

Cl2(g) + H2(g) → 2 HCl(g)
As the reaction is exothermic, the installation is called an HCl oven or HCl burner. The resulting hydrogen chloride gas is absorbed in deionized water, resulting in chemically pure hydrochloric acid. This reaction can give a very pure product, e.g. for use in the food industry."

https://en.wikipedia.org/wiki/Hydrogen_chloride#Production

Hydrochloric acid from salt, water, electricity and daylight........?
Somebody please, shoot this down


/CJ




There was a thread on this a while back: http://www.sciencemadness.org/talk/viewthread.php?tid=2154#p...

Melgar - 13-5-2017 at 02:14

Quote: Originally posted by Corrosive Joeseph  
Hydrochloric acid from salt, water, electricity and daylight........?
Somebody please, shoot this down

Sure, I'd be happy to help!

Hydrochloric acid is basically a waste product in industry, so nobody ever bothers to actually make the stuff. It's really inexpensive to buy, too. Not to mention, just about any electrode material you'd use to electrolyze brine, is going to have a difficult time staying intact under those conditions. Oh yeah, and gas-phase reactions tend to output drop by drop. It would take forever to make a significant amount.

Corrosive Joeseph - 13-5-2017 at 07:17

Hmmm, thanks guys.......... Of all the 'essential' materials, acids are proving most elusive here.
Back to the drawing board so...............


/CJ

Sulaiman - 13-5-2017 at 07:22

I got my most recent batch of sulphuric acid via Amazon.uk
e.g. https://www.amazon.co.uk/DRAIN-CLEANER-Strength-Instant-Liqu...

JJay - 13-5-2017 at 09:44

Acids, bases, and hydrogen peroxide are pretty much all I can get locally....

clearly_not_atara - 13-5-2017 at 10:07

Quote:
Hmmm, thanks guys.......... Of all the 'essential' materials, acids are proving most elusive here.
Back to the drawing board so...............


I have no Earthly idea why anyone thinks the chloralkali process can be carried out at home, is easy (H2 + Cl2 will explode in 99% of rxn conditions and must be carefully controlled) or really makes any sense at all.

No, seriously: describe how to design a homebuilt reactor to combine H2 and Cl2 in quantity, without catching fire, exploding, or releasing huge amounts of toxic gas. Don't worry, I'll wait

ZnCl2 hydrolysis by contrast is OTC and could be carried out by a well-trained circus monkey.

[Edited on 13-5-2017 by clearly_not_atara]

ave369 - 13-5-2017 at 10:13

If you have concentrated sulfuric acid, all other acids can be easily made from it and the corresponding salts. Sulfuric acid is the "mother" of all acids.

If you don't have concentrated sulfuric acid, you'll have to boil down battery acid. It isn't practical to synthesize sulfuric acid at small scale.

Eyeborg - 14-5-2017 at 05:38

Drain cleaner sulfuric acid is probably your cheapest OTC source. It doesn't matter if it has some gunk in it, it should all be gone after a distillation. If you want bulk, it is probably cheaper to purchase from an industrial supply store.

clearly_not_atara - 14-5-2017 at 14:32

Oh! Ammonium phosphate, found in nearly every fire extinguisher, converts to phosphoric acid upon simple heating. So phosphoric acid is always OTC. This additionally can be used to make hydrochloric and hydrobromic acids from the corresponding halides.

I think you can also use a modified Solvay process to convert sodium phosphate back to ammonium phosphate so that HCl production is catalytic in H3PO4.

Ammonium sulfate under the same conditions gives ammonium pyrosulfate. I think this will react with additional anhydrous ammonia to give ammonium sulfamate, but additional heating will eventually result in complete decomposition to nitrogen, water, and sulfur (among other things).

j_sum1 - 14-5-2017 at 21:34

I believe that fire extinguishers contain a mixture of ammonium phosphate and ammonium sulfate. https://en.wikipedia.org/wiki/ABC_dry_chemical

So, given a mixture of reagents, what would be a suitable procedure for obtaining H3PO4? I am seeing possibilities for all kinds of side products.

clearly_not_atara - 14-5-2017 at 23:48

Ammonium dihydrogen phosphate is apparently soluble in ethanol (ty Wikipedia) whereas ammonium sulfate is not. I believe the same is true of methanol.

[Edited on 15-5-2017 by clearly_not_atara]

Corrosive Joeseph - 15-5-2017 at 00:45

"pH down" from hydroponic gardening outlets is 85% food grade phosphoric acid.
I have found H2SO4 drain cleaner my local farm/feed store but it is not always available.

Nitric from CAN fertillizer and H2SO4 - https://www.youtube.com/watch?v=7akk5ppJjEw&feature=yout...


/CJ

physics inclination - 29-7-2017 at 11:33

Would there be any (reasonably simple) way of making sulfuric acid from calcium sulfate, chemically or electrolytically? Because I can get 40 pound bags of that for $10 from home improvement stores.

Alternatively, and this is kinda more farfetched, but is there any easy way to harvest sulfur from organic matter e.g. fallen leaves or grass cuttings? If so, that would be a convenient way to get sulfuric acid from that sulfur.
I am just personally curious about ways to get reagents that don't require any shopping at all; I'm also making and testing designs for higher-efficiency and maybe higher-output nitric acid electric-arc reactors.

unionised - 29-7-2017 at 13:18

Quote: Originally posted by physics inclination  
Would there be any (reasonably simple) way of making sulfuric acid from calcium sulfate, chemically or electrolytically? Because I can get 40 pound bags of that for $10 from home improvement stores.


Theoretically.
But, by the time you have roasted the sulphate with charcoal at 1000 degrees for a while to reduce it to sulphide, then slurried it in water and passed CO2 through it to liberate H2S then burned that to SO2 and then oxidised that over V2O5 to get SO3 and then hydrated that to get H2SO4, it's probably cheaper (and certainly easier) to just buy the acid.

clearly_not_atara - 29-7-2017 at 13:49

Probably not without reducing the sulfate. If you can selectively reduce to sulfite it's probably better than going all the way to the sulfide, but I'm not sure how to do that. I think concentrated hydrobromic acid could work but for this application that's wasteful and bromine is a side product.

Maybe try heating CaSO4 with oxalic acid? Beware of carbon monoxide.

physics inclination - 29-7-2017 at 14:19
Quote:

Maybe try heating CaSO4 with oxalic acid? Beware of carbon monoxide.


Yes thanks, I found some similar technique that got sulfuric acid by reacting epsom salt i.e. MgSO4 with oxalic acid, and since magnesium and calcium are very similar I imagine it would work well.
here's the video I'm referring to if anyone is curious: https://www.youtube.com/watch?v=ePmbRCiLagE

XeonTheMGPony - 29-7-2017 at 14:23

Quote: Originally posted by clearly_not_atara  
Quote:
Hmmm, thanks guys.......... Of all the 'essential' materials, acids are proving most elusive here.
Back to the drawing board so...............


I have no Earthly idea why anyone thinks the chloralkali process can be carried out at home, is easy (H2 + Cl2 will explode in 99% of rxn conditions and must be carefully controlled) or really makes any sense at all.

No, seriously: describe how to design a homebuilt reactor to combine H2 and Cl2 in quantity, without catching fire, exploding, or releasing huge amounts of toxic gas. Don't worry, I'll wait

ZnCl2 hydrolysis by contrast is OTC and could be carried out by a well-trained circus monkey.

[Edited on 13-5-2017 by clearly_not_atara]


Youd have to be rather inept, I built a functional system at 7!

H2 makes a neat sound when burning in a chlorine atmosphere

chloro alkylie cell, gass scruber > Gas buffer (pressure) > Valves > jar > Needles into jar sealed with good epoxy > Bbq sparker (electric attached to said needles)

Ignition sequence: flood jar with chlorine, start sparker and admit H2 slowly till a steady flame is going, stop sparker, put output tube into chilled water, watch bubbles from distance!

Obviously you'll need to adjust the flame to neutral once it is running, and keep it cool (Combustion chamber) I did that by putting it under a slow stream of water then eventually wrapping it in tubing for less mess.

I discribed the system befor in another thread

[Edited on 29-7-2017 by XeonTheMGPony]

[Edited on 29-7-2017 by XeonTheMGPony]

clearly_not_atara - 29-7-2017 at 17:15

"Looking for cheapest routes to acid synthesis":

$50 worth of valves, $35 for a gas tank, $15 for a tube of epoxy, electrodes (not sure but not cheap), membrane, etc... if you're buying all this stuff it stops being a homebuilt reactor, doesn't it?

And considering that this setup ends with chlorine in a jar, you're doing that for a few *grams* of HCl. 10 liters of chlorine is going to make about half of an ounce of HCl... Anf that seems like a generous estimate.

Also, shouldn't you configure the output tube before ignition? Instructions unclear, room full of hydrogen chloride...

I'm just saying, this isn't solving the OP's problem, it's more of a fun electrical project.

[Edited on 30-7-2017 by clearly_not_atara]

Chemetix - 29-7-2017 at 17:29

Cheap I guess is a subjective thing. Acids are by their nature made with highly reactive chemistry and need some specific engineering. It would be nice to say I made decent amounts of high strength sulphuric from a few jam jars and some cement and epsom salts. Perhaps the holy grail is still out there with a cunning use of OTC chemicals and some ingenuity; the pursuit of which, is half the fun and challenge.

XeonTheMGPony - 29-7-2017 at 18:06

bought? I made it out of stuff from the junk yard! including the mercury, systolic pump, and such. Only the epoxy was bought! (Hood switches and lid switches from washing machines for mercury, screw membranes!)

and when you can leave it running so long as you have water and salt who cares?

Like I said I made this when I was young, now days I'd stream line it more for safety, but fact is I told you a way to easily do it! LOL

When you're poor you need to be creative!
[Edited on 30-7-2017 by XeonTheMGPony]

[Edited on 30-7-2017 by XeonTheMGPony]

Chemetix - 29-7-2017 at 19:19

Xeon-I wish there was a pic, sounds kind of an impressive arrangement.

XeonTheMGPony - 29-7-2017 at 19:31

it was neat and probably very very dangerous I do want to rebuild the whole thing but being an adult sucks as every thing eats my damned money up!

Basically think hofman aperatus, only instead of water it was a mercury bridge that was circulated, the gas buffer was inverted bottles in water tanks then they where fed through some random valves to the reactor, which was rather crude

let the bottles fill up, then run a batch, rinse and repeat.

It would make a meth lab proud I'm sure!

Melgar - 30-7-2017 at 22:56

Quote: Originally posted by physics inclination  

Quote:

Maybe try heating CaSO4 with oxalic acid? Beware of carbon monoxide.


Yes thanks, I found some similar technique that got sulfuric acid by reacting epsom salt i.e. MgSO4 with oxalic acid, and since magnesium and calcium are very similar I imagine it would work well.
here's the video I'm referring to if anyone is curious: https://www.youtube.com/watch?v=ePmbRCiLagE

How has nobody corrected this post yet? Calcium sulfate forms hydrates but is otherwise totally insoluble in water. Magnesium sulfate also forms hydrates, but is soluble in water. That's a HUGE difference! Considering how cheap magnesium sulfate is drugstores though, it shouldn't increase your cost much at all.

clearly_not_atara - 31-7-2017 at 09:33

Quote: Originally posted by Melgar  
Quote: Originally posted by physics inclination  

Quote:

Maybe try heating CaSO4 with oxalic acid? Beware of carbon monoxide.


Yes thanks, I found some similar technique that got sulfuric acid by reacting epsom salt i.e. MgSO4 with oxalic acid, and since magnesium and calcium are very similar I imagine it would work well.
here's the video I'm referring to if anyone is curious: https://www.youtube.com/watch?v=ePmbRCiLagE

How has nobody corrected this post yet? Calcium sulfate forms hydrates but is otherwise totally insoluble in water. Magnesium sulfate also forms hydrates, but is soluble in water. That's a HUGE difference! Considering how cheap magnesium sulfate is drugstores though, it shouldn't increase your cost much at all.

I missed it because it was at the end of a page.

Also seems to be the answer to OP's question, since a certain brand of oxalic acid surface cleaner sits on every store shelf (and for good reason, it works wonders). Magnesium oxalate is almost totally insoluble in water...

PirateDocBrown - 31-7-2017 at 14:00

Quote: Originally posted by Melgar  
Quote: Originally posted by physics inclination  

Quote:

Maybe try heating CaSO4 with oxalic acid? Beware of carbon monoxide.


Yes thanks, I found some similar technique that got sulfuric acid by reacting epsom salt i.e. MgSO4 with oxalic acid, and since magnesium and calcium are very similar I imagine it would work well.
here's the video I'm referring to if anyone is curious: https://www.youtube.com/watch?v=ePmbRCiLagE

How has nobody corrected this post yet? Calcium sulfate forms hydrates but is otherwise totally insoluble in water. Magnesium sulfate also forms hydrates, but is soluble in water. That's a HUGE difference! Considering how cheap magnesium sulfate is drugstores though, it shouldn't increase your cost much at all.



I did wonder how successful Doug was in this video. And how he got the gypsum out of the flask after.