| Pages:
1
..
12
13
14
15 |
Ubya
International Hazard
Posts: 1247
Registered: 23-11-2017
Location: Rome-Italy
Member Is Offline
Mood: I'm a maddo scientisto!!!
|
|
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
---------------------------------------------------------------------
feel free to correct my grammar, or any mistakes i make
---------------------------------------------------------------------
|
|
|
DraconicAcid
International Hazard
Posts: 4333
Registered: 1-2-2013
Location: The tiniest college campus ever....
Member Is Offline
Mood: Semi-victorious.
|
|
I seem to recall reading that molten sodium hydroxide will attack teflon if it's wet. If it's perfectly dry it's fine.
Please remember: "Filtrate" is not a verb.
Write up your lab reports the way your instructor wants them, not the way your ex-instructor wants them.
|
|
|
Herr Haber
International Hazard
Posts: 1236
Registered: 29-1-2016
Member Is Offline
Mood: No Mood
|
|
Teflon melting temp: 327°c
NaOH melting temp: 318°c
|
|
|
DraconicAcid
International Hazard
Posts: 4333
Registered: 1-2-2013
Location: The tiniest college campus ever....
Member Is Offline
Mood: Semi-victorious.
|
|
This a vague-ish memory from a paper I wrote on using molten salts as solvents. I might have been thinking of a eutectic of NaOH/KOH. Or I might be
blithering- if I still had a digital copy, I wouldn't have a program that would read it.
Please remember: "Filtrate" is not a verb.
Write up your lab reports the way your instructor wants them, not the way your ex-instructor wants them.
|
|
|
DavidJR
National Hazard
Posts: 908
Registered: 1-1-2018
Location: Scotland
Member Is Offline
Mood: Tired
|
|
Teflon isn't terribly stable at temperatures that high. Which is the main reason it's not feasible to use injection moulding of PTFE.
|
|
|
kulep
Harmless
Posts: 46
Registered: 19-5-2018
Location: Somewhere below the tropic of Capricorn
Member Is Offline
Mood: Spicy
|
|
I've heard that molten lava might attack some strands of wild teflon, but I'm not sure I can trust those sources
|
|
|
DrP
National Hazard
Posts: 625
Registered: 28-9-2005
Member Is Offline
Mood: exothermic
|
|
| 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 |
lol - yea - molten lava 'attacks' most things I think.
\"It\'s a man\'s obligation to stick his boneration in a women\'s separation; this sort of penetration will increase the population of the younger
generation\" - Eric Cartman
|
|
|
DrP
National Hazard
Posts: 625
Registered: 28-9-2005
Member Is Offline
Mood: exothermic
|
|
I had to look that up as it goes... I found nothing. What is 'wild' Teflon? Are there cases of PTFE being found in nature then? I was not aware and
can find nothing about it.
\"It\'s a man\'s obligation to stick his boneration in a women\'s separation; this sort of penetration will increase the population of the younger
generation\" - Eric Cartman
|
|
|
The jersey rebel
Hazard to Self
Posts: 76
Registered: 27-5-2016
Location: Jersey Fresh
Member Is Offline
Mood: dealing with excessive change
|
|
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 
Water is wet, fire is hot, I'm a jersey born rebel
AKA the roguemillenial on other sites.
|
|
|
JScott
Hazard to Self
Posts: 51
Registered: 23-8-2018
Member Is Offline
|
|
Plastic keck clips, understand fire extinguishers
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.
|
|
|
Deathunter88
National Hazard
Posts: 519
Registered: 20-2-2015
Location: Beijing, China
Member Is Offline
Mood: No Mood
|
|
| 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.
|
|
|
JJay
International Hazard
Posts: 3440
Registered: 15-10-2015
Member Is Offline
|
|
Today I generated several moles of nitrogen dioxide in a few minutes in a tiny makeshift fume hood. That was definitely not a very good idea. As I
stared amazed at the huge blob of brown gas sitting inside the fume hood, I decided to adjust the intake to pull out more of the gas more easily. So I
flipped the front cover open.
When your fume hood is full of nitrogen dioxide gas, do not open it.
I backed away from the horrible choking mess with my eyes burning, barely able to breathe, and the hood sealed itself. Eventually, it cleared.
[Edited on 21-11-2018 by JJay]
|
|
|
XeonTheMGPony
International Hazard
Posts: 1640
Registered: 5-1-2016
Member Is Offline
Mood: No Mood
|
|
| 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
|
|
|
JScott
Hazard to Self
Posts: 51
Registered: 23-8-2018
Member Is Offline
|
|
A very good idea!
|
|
|
j_sum1
Administrator
Posts: 6320
Registered: 4-10-2014
Location: At home
Member Is Offline
Mood: Most of the ducks are in a row
|
|
I don't think I am very good at making dioxane.
I had a whole string of mishaps tonight. Some amusing.
As I indicated, I think there is something seriously wrong with the dioxane I synthesised from antifreeze. It reacts with NaOH to form a tarry
substance. It boils too low. And it reacts with sodium. I think it is more than just a bit of water in it. But anyway I had a small amount that I had
redistilled and thought I might try my luck at isolating some Na from Mg/NaOH thermite. Fun times.
1. I used a cast iron pot with lid for the thermite. Part of the product was a very fine powder clinging to the lid. That was pyrophoric. Interesting,
and not expected.
2. Dropping a few lumps of the mixture into a flask of so-called dioxane: about 25mL, there was a bit of fizzing of H2. Kind of expected since I
suspected that fraction was not completely dry. Later, while tidying up a bit I stoppered the flask. All bubbling had stopped and I did not think much
of it. Even later, I picked it up to move it somewhere else and the stopper flew 3 feet in the air and right across the bench. It singled out the one
piece of glass at that end of the bench and smashed into tiny pieces. The only good news is that particular item was already broken and I had gotten
it out for photographing and measuring so that a replacement could be made.
3. I decided not to leave a container of pyrophoric sodium powder unattended in my lab overnight. After stirring it actually caught alight a second
time. I took it outside to burn out. That looked pretty. I then decided to douse it with water from a distance of several metres. Some nice
fireworks. That was actually pretty cool.
Ultimately I have nothing to show from a mole of Na and several hours of dioxane preparation. Not unless you count a shattered stopper for an antique
iodine flask.
|
|
|
Σldritch
Hazard to Others
Posts: 309
Registered: 22-3-2016
Member Is Offline
Mood: No Mood
|
|
In my experience PTFE reacts with Sodium Hydroxide at dull red heat to form Sodium Fluoride, Sodium Carbonate and formaldehyde which instantly burns.
This was tape on molten hydroxide so maybe the leidenfrost effect increased the effective reaction temperature.
|
|
|
Felab
Hazard to Self
Posts: 76
Registered: 9-11-2018
Member Is Offline
Mood: :dooM
|
|
Sometime ago I was recrystalizing some AgNO3 and I allowed it to cool on the fridge. Someone opened the door and an extremely corrosive AgNO3 solution
spilled all over the place, staining the fridge, the dishwasher, my grandma and me.
Lesson: be aware that other people exist.
The good thing was that I discovered a non-toxic remedy for AgNO3 stains.
|
|
|
hissingnoise
International Hazard
Posts: 3940
Registered: 26-12-2002
Member Is Offline
Mood: Pulverulescent!
|
|
| Quote: | | The good thing was that I discovered a non-toxic remedy for AgNO3 stains. |
You did?
Pray tell...
|
|
|
morganbw
National Hazard
Posts: 561
Registered: 23-11-2014
Member Is Offline
Mood: No Mood
|
|
@Felab, so you know how to remove the stains from my skin?????
|
|
|
Felab
Hazard to Self
Posts: 76
Registered: 9-11-2018
Member Is Offline
Mood: :dooM
|
|
You take some steel wool (the one that is used for polishing wood, not for washing dishes) and soak it in 3% H2O2. Toothpaste can be mixed with the
H2O2 for better consistency. The thing will warm up and fizz. You rub it on your hands for a good while and your stains will be gone or much lighter
than they where. If the steel wool starts cooling down and your stains aren't gone, soak it in fresh H2O2/toothpaste solution. It is what I usualy do
when I get stained.
[Edited on 15-1-2019 by Felab]
|
|
|
j_sum1
|
Thread Pruned
24-1-2019 at 13:58 |
Blarglesworth
Harmless
Posts: 7
Registered: 1-2-2019
Member Is Offline
|
|
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. 
|
|
|
Vomaturge
Hazard to Others
Posts: 286
Registered: 21-1-2018
Member Is Offline
Mood: thermodynamic
|
|
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]
|
|
|
woelen
|
Thread Moved
23-5-2019 at 11:42 |
j_sum1
Administrator
Posts: 6320
Registered: 4-10-2014
Location: At home
Member Is Offline
Mood: Most of the ducks are in a row
|
|
One of those, "what the hell was that" moments.
Some time ago I picked up my container of barium chloride (original packaging) to find a small crack in the bottom and a spill of white powder.
Obviously a need to transfer to a new container. I swept up the spill to dispose of it properly. It was probably less than a gram in total, but I
like playing cautiously with barium compounds. My standard procedure for these kind of things it to convert it to an insoluble form and mix it with
cement and sand to form a cement block that I can dispose of as solid waste. So I mixed up some magnesium sulfate solution and added it to the beaker
containing the swept material.
And left it there. For several months.
Or so I thought.
Today I needed a clean beaker, which meant that a clean-up was overdue. I proceeded to add sand and cement to what I thought was this offending
barium waste to make my concrete block. After addition of water I was greeted with the unmistakable waft of hydrogen sulfide and considerable
bubbling.
I think I must have cleaned up the barium earlier. But what the hell was in that beaker that would cause H2S on the addition of cement?
|
|
|
Sulaiman
International Hazard
Posts: 3695
Registered: 8-2-2015
Location: 3rd rock from the sun
Member Is Offline
|
|
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
CAUTION : Hobby Chemist, not Professional or even Amateur
|
|
|
S.C. Wack
bibliomaster
Posts: 2419
Registered: 7-5-2004
Location: Cornworld, Central USA
Member Is Offline
Mood: Enhanced
|
|
The first question is what is your BaCl2 really and how much did you pay for it. I've mentioned getting a big surprise from some cheap BaCO3. Both of
these are made from BaS obtained by reduction of barite.
The second question is why "BB Code is Off" in this thread?
[Edited on 18-8-2019 by S.C. Wack]
|
|
|
| Pages:
1
..
12
13
14
15 |
![[*]](images/xpblue/default_icon.gif){kind=icon}
