Carbon Steel, Experiment.

[YT2095]

this one`s just for the few that like to see things with their own eyes.

 

I had a sulphuric acid excess from a prior synth, I figured I`de got enough of most sulphates so I`de make some FeSO4.7h2O to top up a chem that I don`t use much in the lab but in the gardens as a Moss killer.

 

the 150ml of 50% H2SO4 went in a 250ml conical flask with some "ancient" rusty old screws.

I left it on the heater overnight and next morning, still fizzining away happily were what looked like pins in a green soln with "black stuff" floating on the top,

 

that was then filtered off and tested, yes, it had managed to take the Carbon out of Carbon Steel, and left it floating around the edge

 

try this yourself, but rem, it has to be OLD untreated or plated screws or nails, ideal if you can see Rust all over them too

[ed84c]

Where is H2SO4 available/ made, from?

[budullewraagh]

you make H2SO4 through the lead chamber process:

3S(s) + 2KNO3(s) --> K2S(s) + 2SO2(g) + 2NO(g) (sulfur + KNO3 reaction)

S(s) + O2(g) --> SO2(g) (combustion inside the chamber)

3NO(g) + 3/2O2(g) --> 3NO2(g) (spontaneous at STP)

3NO2(g) + 3SO2(g) --> 3SO3(g) + 3NO (catalyzed oxidation of SO2 by NO)

SO3(g) + H2O(l) --> H2SO4(aq) (hydrolysis)

 

i do not suggest trying this for many reasons. the gases are all very toxic and some hydrolyze to form quite corrosive acids.

 

i suggest you obtain car batteries, charge them as much as possible, open them and filter the insoluble lead sulfate. you should get 35-40% sulfuric

[Hexaditon]

Sulfuric acid can be prepared from other acids and sulphates.

A more practical setup for the homelab would be an electrolyte-cell that can convert common sulphates into acid (similar to how a battery charger works for lead sulphate to h2so4). Preparation for this will need research so if that's your route report any results.

 

For a commercial source of sulphuric acid - Car battery electrolyte (as mentioned) is a moderate source. It would be far more practical, however, to buy just the electrolyte which you can obtain from a place like NAPA for $15 for 5 gallon (this is true for me in Soutthern California - and a few people in the northeast region of the United States; as well as sources in Canada report similar findings) or you can get it by the quart more readily at other auto shops. Just call and ask for car battery electrolyte or battery acid. This is also a more pure source due to the fact that it does not have such a high lead contamination factor of a car battery directly nor is it wastefully expensive as a battery.

 

Battery acid is as stated around 35% concentration which can be easily concentrated further by boiling off the water which has a BP of 100oC (anhydrous H2SO4 boils with decomposition around 300oC). An azeotrope is fromed at 98% with water at atmospheric pressure which is about the highest you're going to get if not a little under through boil-concentration. That should be great for your needs.

 

Another common source - a tad more expensive however it is more concentrated - is drain openers. With a little searching through major hardware stores - go to plumbing sections and look up MSDS sheets for any drain openers that are within plastic baggies. Sulfuric acid based drain openers are between 90% to 95% concentration depending on the brand. Certain brands have an ugly black additive that dyes the acid (example I have would be Roebics... I believe is the name - is it liquid fire... I don't have it with me) while other brands are more concentrated and have clear additives. Rooto Professional Drain Opener (obtained from Ace Hardware) is an example of the latter. Black dye do not distill over so in using it for nitric acid production or other - eventually distilling - applications will only make the reaction murky for the time being. The dyes and additives can be removed through vacuum distillation of the sulfuric acid (at a pressure in which h2so4 vaporizes without decomposition).

 

That should clarify that.

-Hexaditon

[budullewraagh]

just to follow that up, i have never seen battery acid sold anywhere, although i do live in an area where oxidizers in general are not sold. as well i have never seen sulfuric acid sold as a drain cleaner, although i have heard it has been used as such.

 

be very careful when boiling sulfuric acid. its corrosiveness increases significantly under high temperatures. when boiling it at high concentrations you have a variety of dangers; the oleum fuming out as well as bubbles. just one bubble can result in quite a burn. have a bucket of water with you at all times, lest you corrode your hand off

 

i am quite positive that it is not sold commercially at 95%. at this concentration it fumes oleum, acts as an oxidizing agent, causing fires on contact with organic matter, and is overall really corrosive. i believe it is sold as a cleaning agent at 20% or so.

[Crash]

just to follow that up, i have never seen battery acid sold anywhere,

 

neither have i but thanks to where i work i they get 20L to put in the new batteries that come in! which in other words means that i get quite a large H2SO4 (pretty conc) supply..............as long as they dont catch me lol.

now to find some old old nails or screws.....

[jdurg]

I too live in southeastern New England and don't readily see battery acid available at any auto stores. If you can get it, you have to ask for it and for some reason auto parts stores will try to sell you a new battery instead of giving you the battery acid. I have seen sulfuric acid used in drain cleaners as well, but the ones I always find have so much other crap in there that the acid becomes almost useless. There are either some type of perfumes or thickeners to make it act like a sludge instead.

[raivo]

I suspect that right place to ask for battery acid is those auto or agriculutral machine stores that are mostly for repair parts and cheap stuff. I never had problem finding battery acid in europe.

 

Battery acid is easy to boil to 80...90% concentration. Boiling temperature increases as concentration becames higher, so you need heater that can heat liquid at least to 200C (this is gives 80% conc), for 90% you need temperature no less than 270C. You need thermometer to measure temperature. At 280C H2SO4 starts to decompose so you get lot of white toxic fumes and lose part of your product if you go over that point.

 

Note that by white fumes you can not decide what concentration or temperature is because fumes start to form at far lower temperatures.

[jdurg]

Also, do this in a glass or ceramic pot. There are far too many stories of idiots out there who read about how to concentrate battery acid online or in the "Anarchist's Cookbook" and went ahead and did the concentration in a metal pot. Let's just say they weren't too pleased with the results. (Even better are those who used a copper pot since they figured copper would only react with HNO3. Little did they realize that as the acid was concentrated at an elevated temperature it would be able to oxidize the copper as well. lol).

[raivo]

Yes, jdrug, this is all right and also what bud said about safety. Concentrating of sulfuric is surely not first lab boiling experiment one should do. Most important is to be aware of bubbles that can spray you or nearby things with hot acid. Even soft boiling can suddenly splash. You should be ready for sudden breaking of glassware (especially on heating).

 

All lab setup must be done in such way that even in worst case nothing can fly into your face and any hot caustic liquid that accidentally sprays out will be noticed and easyli cleaned after work.

[YT2095]

doesn`t anyone consider using anti-bump boiling beads these days?

 

*sigh*

 

anyway, before another thread goes OFF TOPIC again (and there are existing threads ad nauseum about this already here), the acid does NOT NEED to be conc, in fact conc won`t work as well!

a good 20 to 40% is just fine, I used 50% as that`s what I had left over, it worked much better when I diluted it with distilled water.

 

forget this 98% stuff! it`s useless for most applications anyway, I really don`t understand everyones "hang-up" about having the most conc acid

[budullewraagh]

doesn`t anyone consider using anti-bump boiling beads these days?

say what?

[Hexaditon]

Battery acid is around, call around. Some auto-stores don't like to sell it because it's popular for meth labs, but that is RARELY a problem. Although in all honesty, if you're living in a drug-run town that could be a problem... which I'm sure some people encounter. 95% Sulfuric acid is sold commercially as mentioned... however as also mentioned there are additives in the acid. The implications in this statement is the additives are used to absorb heat evolution and etc. It is still VERY dangerous, and cannot be used for septic tanks and plenty of other problems. There is good reason that it is the only drain opener in plastic baggies. Reference MSDS if one is in doubt. Companies make the MSDS available online.

 

What was said by jdurg is VERY important. In one sentence: KNOW YOUR CHEMICAL. Some chemicals don't like some setups. The general rule is to use glass. However there are exceptions (i.e. concentrated phosphoric acid will attack silicate at certain temperatures). So the best advice for dealing with chemicals is knowing the chemicals.

 

On to bumping. As I mentioned earlier in this forum, having a practical organic chemistry book (atleast as reference) isn't a bad idea. I suggested Vogel's 3rd because you can obtain it free and it's IMMENSELY comprehensive. One of the first topics it discusses is bumping and techniques to diminish the problem from heating techniques, to porous pellets, to little glass u-tube thingies that do something rather....

 

Anyhow I'll try to conceptually explain bumping. Granite the mechanics are a little more complicated and I am overgeneralizing the source of bumping.... but it is conceptual. Bumping is when the pressure of the bubbles boiling are higher than the atmospheric pressure causing very chaotic boiling and splashing. How does this happen? Look at it like this...

 

You have a cup of water sitting in the sun. The atmosphere pushes down on this cup of water to keep it from floating away and keeps it condensed. Everything has a characteristic vapor pressure... That vapor pressure increases with an increase in temperature. When the vapor pressure overcomes that of the atmospheric pressure.... you got vaporization - the molecules will leave the liquid and be expelled into the atmosphere in gassous state. This temperature (thermal kinetic energy) in which the composition can overcome atmospheric pressure is typically referred to as a boiling point (making sense eh?.... see how vacuums reduce the boiling point?). Now we have this cup - and we apply heat to the BOTTOM of the cup. Boiling point for water is 100oC of course... this is the point where the vapor pressure overcomes atmospheric pressure; however, when the bottom of the cup reaches 100oC exactly ideally speaking it will not vaporize. Think think think. It's not overcoming only atmospheric pressure, but the hydrostatic pressure of the water on TOP of it. If it's a big barrel of water the water can be what I believe is called 'superheated' at the bottom because it is under much higher pressure than that on the top of the solutions. This is fluid physics. Weight of water pushes down on bottom water causing increase in pressure at bottom. Ok so it doesn't vaporize at 100oC.... no no no it gets hotter... superheated. There is a point though that it DOES overcome the hydrostatic pressures of the water on top of it... and what do you think will happen? A bubble forms with the vaporized, superheated water that and rises to the top of the fluid where it is expelled into the atmosphere. Say what? What's bumping? The bumping is due to the fact that the vapor pressure is much higher than that of the atmospheric pressure causing a violent thrusting release. Anyone ever experiencing this knows that it can get pretty messy and even release acoustic energy in "pops". Typically however, on a home lab scale - this isn't incorporated until you get into heavy or large or very hot solutions. It is good knowledge to have in such an event. Boiling acids (sulfuric acid is relatively viscous to water and inheritely can have this problem) is an exceptional danger due to acidic ... dangers.

 

Again that was conceptual and not excatly material to write a book with.

 

la la la

-Justin

[budullewraagh]

popular for meth labs? i'd think a birch reduction to be significantly easier then RP/HI considering material availability. people are so paranoid

 

i'd like to find that 95% sulfuric somewhere. do you happen to know any brand names?

[Hexaditon]

I pointed out the two I have in my possession and I have found around myself.

Just for you I will go over to my lab and get the dyed one.... one second...

 

Roebic: Drain Flow Blended Sulfuric Acid Drain Opener.

Here's the MSDS: http://www.roebic.com/pdf/DrainFlowMSDS.pdf

Sulfuric acid in this one is 90% according to MSDS, it's the first one I obtained before I found my other (it contains black additives).

This was obtains from Lowe's Hardware.

 

Rooto "Professional Quality": Professional Drain Opener

The MSDS is no longer online or I didn't find it with a quick search. You can titrate it to find the exact concentration, however it was 95% or so when I used density tests (density tests reported about 99%, however additives make up for the rest).

This was obtained from Ace Hardware (about a month ago so I know it's still present)

 

Home depot once carried something, I never obtained it; it does not carry it anymore in my location.

 

Other brands that I've heard, but do not have in my possession now can be found with more search. As stated, once again, because I love repeating myself, go into a hardware store and go to the drain opener section and look for any wrapped in a plastic bag. Go home check the MSDS and see if it is what you want.

 

It's about $10 per quart. Roughly.

 

-Hexaditon

[budullewraagh]

the roebic is 90% DILUTED sulfuric acid, meaning there is 90% sulfuric+water and 10% other things. this makes much more sense

[jdurg]

Whenever I had to heat a solution of anything in a chemistry lab we threw in some ceramic chips to preventing bumping of the solution. It's actually pretty easy to see overheated water in the home. If you have a somewhat tall glass that can go in the microwave, fill it up almost to the top with water. Then heat this inside the microwave for a while until it begins to boil. Once its boiling, turn the microwave off and let it sit for a good 10-20 minutes. Then turn the microwave back on and heat it up for a while. You'll notice that the water doesn't really boil when you think it should. After a while, turn the microwave off. Now from a VERY far distance, drop a sugar cube into it. (You might want to put one on the end of a yardstick and let it fall off of the end). The addition of the sugar cube will provide the seed needed for the superheated water to vaporize and it will suddenly vaporize in a violent manner.

 

Now this doesn't happen all the time, but if you try it enough times you should be able to see it happen. However, remember that it's incredibly dangerous because that water is at a temperature greater than 100 degrees C and can cause massive burns and possibly shatter the glass. (It's also more prone to happen to a cup of distilled water as opposed to tap water).

 

In order for something to boil, just as in freezing, it needs a "seed" to get started. If there is no 'seed' bubble for the solution to work off of, it's temperature will just rise and rise. Then when it gets that 'seed' it will quickly boil all at once. The boiling chips will provide the 'seed' that the solution needs in order to boil and will severely prevent this violent occurance from happening.

[Hexaditon]

the roebic is 90% DILUTED sulfuric acid, meaning there is 90% sulfuric+water and 10% other things. this makes much more sense

 

Allow me to redirect you on another path of thought. 90% Sulfuric acid is considered diluted in itself. Sulfuric acid according to this text I'm holding is considered to be atleast 18M.... I don't know the validity of this number (you can translate it into precentage by weight). The thing is that there's a certain concentration that H2SO4 is considered to be concentrated (as any acid... i.e. HCl is considered concentrated at 35%). Sulfuric acid is considered concentrated around 95%. So when the solution has a concentration below that mark it is considered diluted sulfuric acid. My Roebic's MSDS gives warning "Contains sulfuric acid" where as my Drain Rooto has a warning "Contains concentrated sulfuric acid". That tag is really just a relative number to give you an idea of how bad is it (suppose to treat one with more care than the other.... storage for battery acid is a bit different that storage for industial 98% h2so4.... the line had to be drawn at a certain number; how those lines are drawn I'm uncertain). 90% H2SO4 is tagged diluted just the same as battery acid. The other 10% of the solution is primarily water with additives.

 

-me

[budullewraagh]

i must say that a mixture containing 90% 18M H2SO4 and 10% other solutes/suspensions would not be sold with such little labelling as you are describing.

 

people do not like oleum.

 

there should be warnings all over saying "warning: this product contains free oleum and fumes oleum"

there should be a warning saying "warning: this product will corrode your hand off in minutes"

theres hould be a warning saying "warning: this product is an oxidizing agent as well as a dehydrating agent. it will start fires with certain organic matter and will react vigorously with reducing agents."

 

such a product would be absurdly excessive. you don't need too strong of an acid to unclog drains and if you need something strong you can use the NaOH/H2O2 mixture that is commonly stored...18M sulfuric acid is just overall too dangerous to sell to the public.

 

yes, i know some chem suppliers sell 18M sulfuric acid to the public and thats how i got my 2 liters of it, but that's different

[YT2095]

the FeSO4 crystals are all formed now

 

but I noted an interesting observation, there is a Smell to it.

a "Dry" slightly metalic odor?

I get the same smell when opening the lid on the jar of rusty old nails and screws that I keep for reasons unknown.

 

it seem perculiar to Iron based materials, as I don`t get any smell from Copper or Zinc based materials at all?

 

why is this? or am I alone in this observation?

 

edit: and before anyone asks how something can smell "Dry" don`t bother, it`s just the only way I can explain it, same as a red wine can taste dry even though it`s a liquid.

[fishy1]

Also, do this in a glass or ceramic pot. There are far too many stories of idiots out there who read about how to concentrate battery acid online or in the "Anarchist's Cookbook" and went ahead and did the concentration in a metal pot. Let's just say they weren't too pleased with the results. (Even better are those who used a copper pot since they figured copper would only react with HNO3. Little did they realize that as the acid was concentrated at an elevated temperature it would be able to oxidize the copper as well. lol).

would any glass do??? like just normal cooking stuff, or do you need lab equipment(i'm sure i heard somewhere strong acids dissolve glass(i know HFl does))

[raivo]

Sulfuric acid will not dissolve glass but only high quality heat resistant glass is safe to use because other glassware may break by heating.