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Hawkguy
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Registered: 10-10-2014
Location: British Columbia (Canada eh!)
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HOLY FUCK Like 5 minutes ago things went to shit. So I was recrystallizing Urea, I had about 800ml of half dissolved Urea solution bubbling, when the
glass broke, and it went everywhere. The hot burner vaporized a lot of the stuff, so now it looks like a smoke bomb went off in the kitchen (I only
use the kitchen for somewhat harmless stuff, plus it was really damn cold today). Fuck. Now I need a new giant beaker, and more Urea, which was hard
enough to come by in the first place. At least its not as bad as when a pan full of gunpowder/ firework comp ignited. (Outside, but still scary)
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Heavy Walter
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Hi
By the way, did you use heat spreader?
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j_sum1
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Today's episode comes to you from the files of "things I should know but didn't think all the way through."
And supported by "sometimes you just don't know how significant a phenomenon is until you see it for yourself".
With an encore by, "If you are a real idiot you make the same mistake twice in quick succession."
No real accident I am pleased to say but a bit of wastage of some cheap chemicals and some tidying up to do.
It was time to make some ammonia solution -- difficult to obtain anything but cloudy ammonia floor cleaner in Oz and I have been making do for too
long. However, not something I have had to make before.
Procedure involved ammonium sulfate and sodium hydroxide powders in a three neck reaction vessel with water being added via addition funnel. NH3
evolved was bubbled through chilled water in a measuring cylinder. I was aiming for a 25% solution and decided on about 60% excess ammonia production
to make sure I got there. Excess gas from the cylinder was passed into a shallow bowl of water via an inverted funnel to prevent suckback.
My main mistake was overlooking how much cooling the reaction would need. I didn't have any ice easily available to chill the measuring cylinder and
foolishly decided it wouldn't matter too much.
A few minutes into production and the measuring cylinder had heated up so much that no more ammonia could be absorbed. The solution was bubbling and
boiling so much that it was in danger of squirting all over the place. I quickly switched to a new cylinder: a bit concerned because there was still
a lot of gas being produced. Of course in my haste to fix the situation I did nothing to prevent suckback. All went well for another few minutes.
The reaction slowed a bit and I decided to increase the water drip rate from the addition funnel. Next thing I knew and 250mL of solution was sucked
out of the cylinder and into the reaction flask: of course greatly accelerating the reaction. Now, I have seen videos of an ammonia fountain before
but really was not prepared for how swift and suddenly it could happen.
I now had a slightly overfull three-neck still spitting out ammonia gas. I figured that I may as well refill the cylinder with chilled water and get
the rest of the ammonia if I could. I'd watch it carefully this time. It seemed to work. A bit of gentle heating and I was again collecting some
nice solution. When that one started to warm up I swapped again.
It doesn't pay to be too confident. I left the lab for a few minutes and came back to the results of another ammonia fountain. The cylinder was
again empty and this time my reaction flask was completely full right up into the addition funnel.
Things to learn.
This is one that must be kept cool.
60% extra ammonia was too much.
Ammonia sucks at water like a camel in a salt mine. You have to plan for that.
The yield? Density measurement on my first collection revealed a concentration of 23.5% -- close to what I was aiming for. I also got 250mL of some
more dilute solution. I haven't measured it but guess around 10%.
So, by no means a disaster. But definitely not the way that I want to be working. It would not have been a good day to have been working with
anything really hazardous.
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Texium
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I've been quite frustrated for the past few days about a Jones oxidation of n-butanol to butyric acid that I've been working on. The oxidation went
fine. Then I decided to neutralize the mixture and precipitate the Cr(III) with bicarbonate and filter it. It worked fine for neutralizing it, but
most of the Cr refused to precipitate, even with excess bicarbonate added. To make matters worse, whenever the slurry is heated or put under reduced
pressure, it foams like mad in an uncontrollable way. I tried adding ammonia to some, and this seemed to cause the rest of the Cr(III) to precipitate,
but there was still too much dissolved gas to vacuum filter it, so I gravity filtered some. I found that the filtered solution was yellow, and turns
orange when acid is added. This seems to indicate that there is still Cr(VI) present, which is strange since I used an excess of butanol. However, I
did notice a fruity smell throughout the course of the oxidation and handling afterwards. I'm not sure if it's butyraldehyde or butyl butyrate as I
have not smelled either of them, but I've narrowed it down to those two compounds since I don't know what else it could be. The presence of either
could explain the apparent Cr(VI) in the solution.
The whole situation goes to show how a supposedly simple procedure can have so much unexpected stuff go wrong with it...
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aga
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Registered: 25-3-2014
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Paragraphing should be made a Rule 
What's the puke smell stuff for zts ?
I noticed butyric acid a while back, although saw no use for it at the time.
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blogfast25
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It stinks like rancid butter (which contains some of it) but makes really nice smelling esters. pine-apply, IIRW...
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JJay
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I haven't done any chemistry in a week (building a new lab - today I got delayed by CNC router table wiring issues), but I have been lucky lately - I
haven't broken any glass in the past month and a half except when I torched a department store test tube to red hot and dunked it in water to check
its quality. Of course tomorrow I will probably drop an addition funnel on concrete or spill sulfuric acid in my vacuum pump.
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KesterDraconis
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I broke a round bottom flask recently. What out were you have even the slightest water. The thing was hot and I had to put it somewhere that it
wouldn't fall over/roll somewhere, and I saw this pot sitting on the table nearby. I placed it in said pot. The pot had a tiny layer of water on the
bottom.
I admit, it was cheap glassware, and I probably shouldn't have been using it anyways, but dang it annoyed me to find it cracked!
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The Volatile Chemist
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Location: 'Stil' in the lab...
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In AP chem we did a lab on equilibrium reactions, and we had to go from table to table with a test tube rack filled with various glassware needed for
our group at each station. A partner had put all the needed glassware into the rack, and I only felt the need to check that everything was there. In
pouring some KSCN - Fe(NO3)3 solution into a rather long test tube, I was immediately made aware it was lacking a
bottom...Thankfully the teacher wasn't nearby, and only a few chuckles were made about 'Nathan's bad chemistry skills'. These were countered with
comparing the parties voicing such thoughts with garbage.
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Etaoin Shrdlu
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Unprofessional. Just laugh. It was funny.
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The Volatile Chemist
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Well, the garbage part was actually the result of one of such parties noting that a beaker labeled 'waste' was reminiscent of me. I then retaliated by
stating after the lab I would show him an evolutionary tree showing he was closer-related to garbage. Perhaps unprofessional.
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Texium
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Location: Salt Lake City
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Quote: Originally posted by The Volatile Chemist  |
Well, the garbage part was actually the result of one of such parties noting that a beaker labeled 'waste' was reminiscent of me. I then retaliated by
stating after the lab I would show him an evolutionary tree showing he was closer-related to garbage. Perhaps unprofessional. |
Yes, and also a better comeback in theory than in practice, I'd think. :/
Try not to take that sort of stuff to heart. When you do it makes them want to say stuff like that more in the future.
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JJay
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Registered: 15-10-2015
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Just ask if they'd like a glass of warm prussic acid 
But seriously, it's best to avoid referring to people has human refuse or discussing how there are a lot of eels in their part of the gene pool and so
forth....
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aga
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Registered: 25-3-2014
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Double Whammy
Tried chlorinating ethanol again.
Didn't work, yet it did last time, easily.
The Cl2 cannot be different to last time (same chemicals from same containers) so tested the latest batch of 'super dry ethanol' with a
potassium permanganate crystal and it turned all purple.
Damnit ! It's still got a significant amount of water in it.
Gas mask off, brief sniff of the result of the chlorination.
Smells like chloroform to me.
Appears that EtOH + Cl2 goes all Haloform if there's any water around.
Previous ethanol batch was treated with homemade tripotassium phosphate to get the last few % water out.
This ethanol batch was treated with purchased K2CO3.
OK.
Make some more K3PO4 to rip the water out of a fresh batch of ethanol before trying the chlorination again.
200ml of 76% (green farm-feed grade) H3PO4 in a 500 ml comical flask.
Start lobbing in KOH.
Some flakes heat, splutter, react like mad, others do nothing !
Damned KOH is as impure as hell too !
During cleanup a small ammount of TCCA got on my blue lumber jacket, which now has a white spot.
Oh the horror. The horror. The horror ...
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blogfast25
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Hmmm... sounds a little bit like:
'Oh the haste. The haste. The haste... That maketh the Waste (?)'
How do you check the anhydrousness of your EtOH (what that KMnO4 trick really consist of)?
Refractometry on 1:1 diluted sample gone out of fashion?
[Edited on 15-1-2016 by blogfast25]
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aga
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The worst bit is the jacket.
I can no longer hide under copper sulphate crystals.
Where the hell am i going to find a place to sleep tonight ?
[Edited on 14-1-2016 by aga]
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The Volatile Chemist
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Location: 'Stil' in the lab...
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| Quote: Originally posted by zts16 | | Quote: Originally posted by The Volatile Chemist |
Well, the garbage part was actually the result of one of such parties noting that a beaker labeled 'waste' was reminiscent of me. I then retaliated by
stating after the lab I would show him an evolutionary tree showing he was closer-related to garbage. Perhaps unprofessional. |
Yes, and also a better comeback in theory than in practice, I'd think. :/
Try not to take that sort of stuff to heart. When you do it makes them want to say stuff like that more in the future. |
You take me wrongly No, I didn't take *that* insult to heart, at least, since it
was from a long-time acquaintance who is continually asking for my assistance in chemistry anyways. But you're right, perhaps I should leave that for
judgement day, eh?
I was making some Na3Cit, and had allowed my naOH to sit out for over an hour before beginning (I had massed it immediately, though). I
forgot/underestimated that NaOH absorbs CO2, and in adding a hot solution of citric acid to the solution of sodium hydroxide a lot of
effervescence was observed. Lots a few mL's of solution, but got awesome crystals in my new crystallizing dish. Also found out that NaOH has a smell
to it...
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karlos³
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I have something to add: Once I prepared a solution of sodium-2-butoxide from 2-butanol and sodium metal, did my reaction with it as usual, and
quenched it trough pouring on icewater. It was not visible at this point, as my solution looked clear, that a very small piece of Na did not react and
consequently catched fire in an explosive manner with a short but loud "bang".
Nothing happened beside me being shocked, not even the alcohol catched fire.
But I was very surprised as I have not expected it.
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Detonationology
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I was refluxing 250mL Et.CH3COO + an excess of NaOH in a 500mL round bottom with a 300mm liebig using a pond pump in a cooler w/ ice and outside
(28˚F).
The first 30 minutes went very smoothly, the vapors condensed @ 100mm mark from the bottom.
As the reflux continued, the ice began to melt, and the condenser was not able to effectively condense the Et.OH + Et.CH3COO.
Hot vapors spewed from the top, making a smelly, volatile mess.
Moral of the story: 1) use an efficient condenser. 2) watch your condenser temp. when doing anything with volatile shit.
3) have a plan ready, and by a plan, I mean ICE.
Also burnt my pinky removing it from the hot plate... boo hoo.
Time to make one of those lab jacks from a car jack.
“There are no differences but differences of degree between different degrees of difference and no difference.” ― William James
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woelen
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A little accident happened here, but it is interesting enough to warn others about it.
I purchased finely powdered CuO (the black oxide) from eBay. It was delivered in a plastic ziplock bag and I transferred it to a glass container with
screw cap. Unfortunately some of the powder was spilled (a few grams at most, only a minor loss). I did not put that in the jar with the other CuO,
afraid of contaminating the main stock.
I scraped most of the the spilled CuO and put this in a small vial and added some 2000 mesh Al-powder to it and mixed well. I had read about the
thermite reaction of CuO and Al and that it is fast and now I have some waste/spilled CuO I wanted to give it a try on a small scale. I took a small
spatula full of the CuO/Al mix and held it in the flame of a propane torch. Nothing seemed to happen, the pile on the tip of the spatula (in fact, an
old screw driver) started to glow orange in the flame. I just decided to dump the little pile when it suddenly exploded with unbelievable violence and
a white flash, spraying many brightly glowing pieces around over a distance of at least half a meter or so. It made little burn-holes in my clothes,
one painful little speck on my hand, and I now have a few little black pits in the workbench. Fortunately nothing more serious happened. The amount
was small (50, maybe 100 mg). I discarded the rest of the mix I made, lighting it will create a too heavy bang and it will spray around many white-hot
sparks all over the place. CuO/Al mix is very powerful and it sprays white hot sparks when ignited. Not something you want to do on a gram scale.
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mayko
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| Quote: Originally posted by woelen | A little accident happened here, but it is interesting enough to warn others about it.
[...]
CuO/Al mix is very powerful and it sprays white hot sparks when ignited. Not something you want to do on a gram scale. |
Yeah, I knew a person who tried this on a multigram scale without any testing and gave themselves third degree burns. This person also tried to remove the label from a closed(!), theoretically empty(!!), oxygen (!!!) tank by
throwing it in a bonfire(!!!!) and acting surprised when the aluminum tank melted.
I'm sort of glad we don't live next to each other anymore.
al-khemie is not a terrorist organization
"Chemicals, chemicals... I need chemicals!" - George Hayduke
"Wubbalubba dub-dub!" - Rick Sanchez
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blogfast25
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| Quote: Originally posted by woelen | | CuO/Al mix is very powerful and it sprays white hot sparks when ignited. Not something you want to do on a gram scale. |
Apparently not always but often:
http://www.amazingrust.com/Experiments/how_to/Thermite_pics-...
And with some 20 % CaF2 mixed in, mine ran smooth and gave a nice copper regulus...
[Edited on 24-1-2016 by blogfast25]
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The Volatile Chemist
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This evening I ran through a prep of calcium citrate. Made up a solution of sodium citrate and a bit of citric acid (to react with residual NaOH from
making of sodium citrate), and a solution of Calcium chloride. ...But no precipitate formed. Unless it really does matter which solution was poured
into which, I can't see why a compound (Calcium Citrate) which has a solubility of 0.9g/L didn't precipitate. Quite disappointing/depressing...
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Etaoin Shrdlu
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Too acidic possibly? Try adding a little NaOH solution. Better an excess of alkali than acid here. Excess NaOH will be soluble anyway.
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JJay
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Today I broke my Claisen adapter. It was an extremely low-quality one that I bought from pricechopper2011. (His flasks, though, have been dropped on
the floor repeatedly with no problems.) I knew it would fail eventually, and today it broke against the stir bearing while I was stirring with a
drill.
Now I have to buy a new Claisen adapter, and I will consider buying a real mechanical stirrer. I'm reasonably sure that a higher-quality Claisen
adapter would not have broken, but I'm not 100% sure, and I'd definitely prefer not to break something more expensive.
[Edited on 10-2-2016 by JJay]
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