When Chemistry Goes Wrong

Quote: Originally posted by TheNerdyFarmer

Yesterday I decided to generate some ammonia gas for a separate project of mine. I had the whole gas generating setup built and so I mixed the reactants and started gas generation. By the way I was making ammonia via ammonium halide salt + alkali metal hydroxide. Any way, the reaction started and a lot of gas was coming off. There was also a good deal of moisture coming with it. Little did I notice that some (a great deal) of ammonia gas was leaking from the tubing that I used to make the gas generating setup. Before I realized what was happening I lifted the sash of the fumehood up and got a huge whiff of ammonia gas. I had forgotten to turn my fume hood on. I quickly turned it on and ran to the other side of the lab. I walked over to the hood every few seconds and within 2 minutes there was no detection of ammonia gas. This wasn't a super dangerous situation but it did give me somewhat of a scare considering that ammonia isnt the greatest stuff to inhale. [Edited on 6-11-2017 by TheNerdyFarmer]

Thanks ninhydric1, I made a solution of the bluing salts and was able to filter off the precipitate, it looks to be mostly copper.

below is a picture of the failed part to be blued, it's the components to a vernier height gauge

Quote: Originally posted by Melgar

Quote: Originally posted by TheNerdyFarmer   Yesterday I decided to generate some ammonia gas for a separate project of mine. I had the whole gas generating setup built and so I mixed the reactants and started gas generation. By the way I was making ammonia via ammonium halide salt + alkali metal hydroxide. Any way, the reaction started and a lot of gas was coming off. There was also a good deal of moisture coming with it. Little did I notice that some (a great deal) of ammonia gas was leaking from the tubing that I used to make the gas generating setup. Before I realized what was happening I lifted the sash of the fumehood up and got a huge whiff of ammonia gas. I had forgotten to turn my fume hood on. I quickly turned it on and ran to the other side of the lab. I walked over to the hood every few seconds and within 2 minutes there was no detection of ammonia gas. This wasn't a super dangerous situation but it did give me somewhat of a scare considering that ammonia isnt the greatest stuff to inhale. [Edited on 6-11-2017 by TheNerdyFarmer] I kind of like the smell of ammonia, because I've come to associate it with neutralization of HCl vapors. I did this one halogenation reaction a lot that necessitated generating chlorine gas, and produced HCl gas. Both gases escaped from time to time, and opening my ammonia jug and squeezing it repeatedly to get the vapors to diffuse would allow me to see where the bad vapors were coming from and stop them. It reacts with Cl2 and HCl in midair to generate salts, which are visible like smoke. This is clever. I have never thought of using ammonia to detect HCl. I will certainly try this in the future. Thanks for the tip! Incidentally, if you want to generate anhydrous ammonia gas cheaply, the most effective way I know of is heating urea to about 200C. It's super easy to control; you just turn the heat up or down. It leaves cyanuric acid residue, which you can use to make cyanates or any number of things. It's hard to clean out of stuff, but will form isocyanuric gas at higher temperatures.

Quote: Originally posted by TheNerdyFarmer

I will definitely try this method next. It seems cheap and does not generate a ton a moisture like the other reaction did.

Quote: Originally posted by TheNerdyFarmer

Using ammonia to detect HCl is pretty clever. I don't know why i have never thought of using ammonia to detect HCl before. I will certainly try this in the future. Thanks for the tip!

Every time I've made an ester I've had low yields, usually in the 50-60% range. Recently I was making diethyl phthalate, and I was determined to get a high yield. I used a large excess of dry ethanol and 3A molecular sieves in a soxhlet, after distilling off the extra ethanol all traces of water had essentially been eliminated. I mixed the residue with water to wash out EtOH and H2SO4, which left a dense oily liquid with a volume of a little more than a quantitative yield. Next I washed with NaHCO3 solution. The first three or four times shaking built up pressure but not too much. Then I shook the sep funnel again, but this time it built up a lot of pressure. Enough to push out the stopper (which I was holding firmly in place) and allow much of my product to be sprayed out onto the bench

Looks like another low yielding Fisher Esterification...

Hmmm I don't think high boiling liquid will be easy to clean from wood.

Hey VS, I'll dilute some and run a test to try plate it out with carbon electrodes as suggested, Thanks.

The formula I use does call for water but I got tired of controlling the evaporation so just let it become a block of solid salts and used it that way.

Quote: Originally posted by BromicAcid

My early mistakes can be found here: http://bromicacid.com/mistakes.htm For those just looking for the high-points here is a list of the titles: Neutralization of Sulfuric Acid Acetone Peroxide H2SO4 / HNO3 What's In a match head? Silver Thermite Phosphorus! Caustic Nightmare Chlorinated

The ammount of luck you have is amazing. Next time shit goes sideways go buy lottery tickets.

More than 7 days into an extraction.

6 hours of painfully slow filtration of 1 litre of goop, halfway complete.



A sudden episode of very high wind wiped it all out.



Bugger.

Tonight I was distilling HCN (produced from ferrocyanide and acid) into alcoholic NaOH to produce sodium cyanide. I need about 2 grams so I did this on a five gram scale. 75% of the way through I forgot watch my trap and bleach/hydroxide solution was sucked into the receiving flask.
Note to self: always use inverted funnel trap. I didn't because I was lazy but now I'll just have to waste time tomorrow.

Quote: Originally posted by Ubya

sodium and concentrated sodium hydroxide can eat teflon

Quote: Originally posted by CobaltChloride

Wait, even concentrated NaOH eats PTFE? AFAIK, only molten very reactive metals (like sodium) react with PTFE to make metal fluorides, while strong bases do not.

Quote: Originally posted by CobaltChloride

Wait, even concentrated NaOH eats PTFE? AFAIK, only molten very reactive metals (like sodium) react with PTFE to make metal fluorides, while strong bases do not.

my bad, don't know why i remember NaOH can corrode PTFE

Teflon melting temp: 327°c
NaOH melting temp: 318°c

Quote: Originally posted by Herr Haber

Teflon melting temp: 327°c NaOH melting temp: 318°c

Quote: Originally posted by kulep

I've heard that molten lava might attack some strands of wild teflon, but I'm not sure I can trust those sources

Quote: Originally posted by kulep

I've heard that molten lava might attack some strands of wild teflon

when I ran a lab years ago, I ended up running into all sorts of problems with stuff unexpectedly blowing up, shattering, or just nearly gassing the house with chlorine after an earthquake knocked over my HCl, which was the first time my lab was raided! Lucky I knew the police because otherwise, things would've ended very differently, and chances are I would've never made a post again.


First point I think is very important to say, if you're on a budget, for the love of all that's good, don't work anywhere near old tools. acid fumes can make the lead paint into a form which will go right through skin. That's exactly what happened to me in an old post I made where I showed my nails, which in fact did have Mee's lines on them. I had a sample sent to a toxicology lab at the request of my doctor and it gave a strong positive for lead and a weak positive for arsenic.

As for what I was working with at the time, don't ask. I still have very deep regrets over my old lab despite having no involvement in drugs or any significant quantity of explosives. Got into a ton of trouble over that thing. Still has a very strong negative effect over my family dynamics and mental state to this day even though I've not even been near a bottle of acid in well over 2 years, let alone a home lab.

My lesson to all of those who are reading this, please don't use home chemistry as a means of coping with a mental disorder. I wasn't in the right state of mind and although my lab worked to get me through school, it also destroyed me in the process, shattering most of my passion for everything and taking away any amount of joy I had in life.

One reason I am online as much as i am under the jersey rebel and roguemillenial is to prevent others from suffering the same fate as me. It's one of the few things that makes me feel as if I've contributed anything to any scientific field

Plastic keck clips, understand fire extinguishers

Quote: Originally posted by JScott

During a nitric acid synthesis the plastic keck clip holding my condenser to the clausin adapter cracked. New hot nitric acid dripped into the mineral oil the boiling flask was submerged in and instant fire. The fire extinguisher was right at hand and the blaze was out in less than ten seconds. There was 900 ml of 95% sulfuric acid in the now cracked boiling flask along with the nitrate (potassium as I recall). The hot acid and oil fumed for more than ten minutes. The fume hood exhaust roared a bit (jet sound) and this filled my neighborhood with a dense white cloud. I was very pleased this didn't bring a visit from the local constabulary. Two take aways... Plastic Keck clips, never again! Ten pound fire extinguisher... much more mess than the fire! Clean up took more than a day. I am also very careful choosing heat sources and try to avoid oils when possible. I now use metal clips and have small 32oz sized extinguisher along with a larger ten pounder. In the case of this fire, as impressive as it was, the smaller extinguisher would have worked fine and cut clean up in half. I only used one small blast of the that larger extinguisher and it had to be replaced (refilling them is a hit or miss proposition in my burg). If you haven't used a fire extinguisher, it would be helpful to at least watch a video of the one you purchased being used (or one much like it). I was very surprised at the volume of material ejected with a small squeeze of the trigger, and the force it came out with is worth considering. This will blow stuff around in most small fume hoods, easily blew my distillation setup half off the hot plate.

Quote: Originally posted by Deathunter88

Quote: Originally posted by JScott   During a nitric acid synthesis the plastic keck clip holding my condenser to the clausin adapter cracked. New hot nitric acid dripped into the mineral oil the boiling flask was submerged in and instant fire. The fire extinguisher was right at hand and the blaze was out in less than ten seconds. There was 900 ml of 95% sulfuric acid in the now cracked boiling flask along with the nitrate (potassium as I recall). The hot acid and oil fumed for more than ten minutes. The fume hood exhaust roared a bit (jet sound) and this filled my neighborhood with a dense white cloud. I was very pleased this didn't bring a visit from the local constabulary. Two take aways... Plastic Keck clips, never again! Ten pound fire extinguisher... much more mess than the fire! Clean up took more than a day. I am also very careful choosing heat sources and try to avoid oils when possible. I now use metal clips and have small 32oz sized extinguisher along with a larger ten pounder. In the case of this fire, as impressive as it was, the smaller extinguisher would have worked fine and cut clean up in half. I only used one small blast of the that larger extinguisher and it had to be replaced (refilling them is a hit or miss proposition in my burg). If you haven't used a fire extinguisher, it would be helpful to at least watch a video of the one you purchased being used (or one much like it). I was very surprised at the volume of material ejected with a small squeeze of the trigger, and the force it came out with is worth considering. This will blow stuff around in most small fume hoods, easily blew my distillation setup half off the hot plate. Get yourself a CO2 fire extinguisher, zero residue and you almost WANT to find a reason to use it.

I use Halon / CO2

Quote: Originally posted by hissingnoise

Quote: The good thing was that I discovered a non-toxic remedy for AgNO3 stains. You did? Pray tell...

Quote: Originally posted by morganbw

Quote: Originally posted by hissingnoise   Quote: The good thing was that I discovered a non-toxic remedy for AgNO3 stains. You did? Pray tell... @Felab, so you know how to remove the stains from my skin?????

I dip a cloth in a strong thiosulfate solution and rub. It takes some effort to get the stains off, since they are elemental silver, but the silver chloride complexes with the thiosulfate and dissolves. If you get AgNO3 on your skin, do this before the resulting AgCl has a chance to see much light - you can prevent stains from happening in the first place.

To get the stains off quickly but non-safely, you can apply a little nitric acid directly to your skin and then wash it off within a few seconds, before a burn forms. But the thiosulfate is recommended.

The Formation of Explosive Diurea From Potassium Iodide And Permanganate

So, as I've mentioned before, I use a Thames and Kosmos C3000 chemistry set as part of an educational program. Yesterday, I tried experiment #134, producing a solution of iodine in denatured alcohol. Everything was set up according to these instructions:



Note: 'spoonful', 'small spoonful', and 'permanganate mixture' mean .3 to .5 ml of dry powder, at most .1ml dry powder, and a mix of 1 part KMnO4 to 2 of Na2SO4, respectively.

Before the flame was even applied, the solution of KMnO4 and KI started to turn dark green and opaque, suggesting the formation of manganate. On heating, the mix boiled and became even darker. A lot of water condensed in the angled tube, and fell into the denatured alcohol. A few dry particles of permanganate were wetted creating purple droplets in the heated test tube, but the promised purble iodine vapors didn't appear.

Well, I thought, there was a reaction, so there has to be elemental iodine in the mixture. If I can just boil all the water off, it will get hot enough to make it evaporate. When most of the water was boiled off, it bumped forcefully. Most of the thick brown goop (a lab partner described it as "shitty") stuck to the sides of the test tube, and a drop made it into the angled tube. I stupidly decided to start dry distilling what was left at the bottom. No purple vapors were visible. At this point I lifted the angled tube out of the alcohol test tube , and put the reaction tube upright, to make the paste fall back to the bottom.When it fell, thermal shock cracked the test tube, although it wasn't visible until I was trying to clean out the tube. Heating the paste at the bottom of the tube did nothing as far as creating iodine. Also, while I was cleaning the reaction products (manganese hydroxides?) out of the tube, the cracked bottom fell off. In over 100 experiments, this was the first piece of glassware from the kit to break. I guess it's 'idiot resistant', not idiot proof

The next experiment involved KI in a divided electrochemical cell. Two cups were connected, as per rhe instructions, with a wide strip of paper towel. With the specified power source (9v) the current was about 200μA, and no visible iodine formed. I decided to just put both electrodes in one compartment, and when some iodine formed near the anode I pulled it out, and rinsed it in the other cup. Soon I had the other cup full of a weak iodine solution, much better than anything from the high resistance divided cell, or the permanganate experiment.

Just before writing this long winded story, I looked in the chem. set booklet again and found this:





Note that next to the drawing it also says to use sodium hydrogen sulphate, not just water, potassium iodide, and potassium permanganate. The written instructions said nothing about this crucial addition. But even if I had seen this before, it doesn't say how much to add, anywhere.

TL;DR I tried an experiment (demonstration, actually) from a chemistry set, the write-up had an error, and instead of making iodine solution, it made a slimy brown mess (see title) and a broken test tube.

The kit has proven to be full of reasonable quality equipment and interesting and informative reactions, but I may write for them to correct this error.

[Edited on 17-2-2019 by Vomaturge]

I do not know what was in the beaker but the incident is a reminder to
HAVE A LAB NOTEBOOK AND KEEP IT UP TO DATE

Hi woelen, while I was studying university I usually had some side-jobs during summer holidays after finishing all exams before new academic year started. One of the jobs was in a distillery which also produced vinegar (by oxidative fermentation of diluted ethanol, 13 % vinegar from reactors was diluted to 8 % and then bottled). My skin and hair were always soaked with smell of acetic acid for at least half a day, nothing helped like washing etc, nothing, just waiting... The distillery processed molasses into spirit, citric acid, vinegar (from ethanol) and whoever knows what else too (yeah plastic bottle from granulate were made too in one building and sent via tube transport system into vinegar building). Oh yes, the distillery produced also some yeast, with terrible smell too...
I have 3x 1 L bottles of butyric acid right now in stock and luckily all in glass bottles, but the first one came in plastic so I transferred it into glass. The plastic bottle did not yet lose its scent after already few months. The same with pentanoic (valeric) acid which came in 1 L plastic bottle. Hexanoic acid came in 1 L glass bottle and from another buy 3 small plastic bottles of 35 mL (I let it them in plastic though, it was not worth to transfer such small volumes into glass).
The valeric and butyric acids were not only in plastic bottle, but the bottles were also in thick evacuated well sealed plastic bags. The empty spaces in carton box were filled with foam foil, the foil is still smelling like vomits after few months till today and the strength seems to be the same.
But the human skin regenerates (unlike plastics) so you'll be OK soon (vinegar disappeared after half a day, butyric acid very likely slightly slowlier due to higher b.p. and better solubility in lipids of skin).
It won't last longer than for 1 month certainly which is usual time of the whole epidermis regeneration/renewal (3 days in psoriasis vulgaris lesions of skin). Depends on how deep did it enter your skin.
Surprisingly the concentrated smell of C4-C6 aliphatic monocarboxylic acids was not so terrible for me (I sniffed directly opened bottles and OK, not using only flapping hand as is necessary for concentrated solution of ammonia in water, directly the bottle, and it was not so bad as I expected), but the worse is diluted smell at very low concentrations. Perhaps the high concentrations benumbed my sense temporarily and thus I'm saying concentrated smell of C4-C6 aliphatic monocarboxylic acids is less terrible than diluted?

Armstrong's Mixture

Quote: Originally posted by woelen

I have the same experience with dilute smell. When I was pouring the acid, the smell was strong, but not as unpleasant as later on. The biggest problem is that I do not get used to the smell. I remain actively aware of the presence of the smell all the time.