| Pages:
1
2
3 |
dicyanin
Hazard to Self
Posts: 57
Registered: 29-3-2020
Location: Europe
Member Is Offline
Mood: inquisitive
|
|
Africa Seeds carries it, but it's really expensive for what is essentially a native weed, $35 for 8 seeds. Monofluoroacetate is toxic to humans, but
other mammals are much more sensitive to it. Attached paper discusses its properties and the preparation of some derivatives.
They also prepare monofluoroacetic acid by refluxing methyl monoiodoacetate with silver fluoride at 170°C in a platinum apparatus , followed by saponification of the ester. Apparently when a platinum refluxing
apparatus is not available, the authors note a lead one can be used.
Attachment: MONOFLUOROACETIC ACID the toxic principle of Gifblaar (Dichapetalum cymosum) _marais1944_20_1.pdf (664kB)
This file has been downloaded 284 times
sic transit gloria mundi
|
|
|
sceptic
Harmless
Posts: 49
Registered: 7-6-2022
Location: Southern Africa
Member Is Offline
|
|
After reading this thread, I'm in no hurry to do so, but if I wanted to extract fluorine compounds from gifblaar, does anyone know of a reasonably
safe way to do it? I ask because here (southern Africa) I have an almost unlimited supply of that plant available.
|
|
|
Texium
Administrator
Posts: 4665
Registered: 11-1-2014
Location: Salt Lake City
Member Is Offline
Mood: Preparing to defend myself (academically)
|
|
I found the previous paper published by the author of the one above. I wasn't able to access the full text, but fortunately the relevant portion was
available:
| Quote: | | Extract 10 kg. dried and finely ground plant material with 96% EtOH for 36-48 hrs., distil the alc. under reduced pressure, dissolve the sirupy mass
in 4 l. water, add 500 cc. 10% H2SO4 and let stand for 1-2 days to allow precipitated material to settle. Filter the solution by suction, extract the
filtrate repeatedly with Et2O, neutralize the combined extracts to phenolphthalein with N KOH and sep. the aqueous solution which contains the K
cymonate. Evaporate the solution to about 300 cc. on the water bath, liberate the free acid by adding the equivalent amount of dilute H2SO4, and
repeatedly extract the solution with Et2O until practically all the acid is removed. Decolorize the Et2O extract with activated charcoal, dry
overnight with anhydrous Na2SO4, filter and distil the Et2O at low temperature Transfer the concentrate to a small distillation flask, collect the
distillate in fractions of 10° up to 160°, carefully neutralize (N KOH and phenolphthalein) the individual fractions, as well as the initial Et2O
distillate, and evaporate the K salt solutions separately to dryness on a water bath. Wash the residues with acetone, dry at 100° and crystallize
from 96% EtOH. The best yields of the K salt are obtained from the 110-160°, fractions. After repeated recrystallization from 96% alc. the salt melts
at 213° with decomposition; insoluble in anhydrous organic solvents except MeOH. |
J. S. C. Marais,
Onderstepoort Journal of Veterinary Research, Volume 18, Pages 203-206, 1943
Apparently before they figured out it was monofluoroacetate, they called the mystery anion "cymonate."
|
|
|
teodor
International Hazard
Posts: 1001
Registered: 28-6-2019
Location: Netherlands
Member Is Offline
|
|
This is molten NH4F inside my DIY home fume hood.
And I am still alive. So, the answer: it depends ...
When I did planning to start playing with F I've selected boron trifluoride and BF4 anion as an entry level but still very interesting F compound.
|
|
|
ItalianChemist
Hazard to Others
Posts: 180
Registered: 26-1-2011
Location: Italy
Member Is Offline
Mood: No Mood
|
|
BF4 anion is very interesting in coordination chemistry since it forms many compounds that can be easily crystallized from water.
Also I don't think it is very dangerous unless it is heated. (It will release some amounts of HF I suppose)
|
|
|
teodor
International Hazard
Posts: 1001
Registered: 28-6-2019
Location: Netherlands
Member Is Offline
|
|
NH4BF4 is quite volatile. I kept it in an open container for drying and it covered inside walls of my cabinet.
I plan to use it for generate BF3 which have many interesting applications in inorganic as well as in organic chemistry. Also it's very potent drying
agent.
[Edited on 21-2-2024 by teodor]
|
|
|
EF2000
Hazard to Others
Posts: 154
Registered: 10-5-2023
Location: The Steppes
Member Is Offline
Mood: Taste testing the Tonka fuel
|
|
Quote: Originally posted by Texium  | I found the previous paper published by the author of the one above. I wasn't able to access the full text, but fortunately the relevant portion was
available:
J. S. C. Marais, Onderstepoort Journal of Veterinary Research, Volume 18, Pages 203-206, 1943
Apparently before they figured out it was monofluoroacetate, they called the mystery anion "cymonate." |
Here's the paper, found it in open access on the University of Pretoria website: https://repository.up.ac.za/handle/2263/59331
Attachment: 19marais1943_18.pdf (279kB)
This file has been downloaded 242 times
Wroom wroom
"The practice of pouring yourself alcohol from a rocket fuel tank is to be strongly condemned encouraged"
-R-1 User's Guide
|
|
|
mr_bovinejony
Hazard to Others
Posts: 130
Registered: 20-4-2018
Member Is Offline
Mood: ASS
|
|
| Quote: Originally posted by teodor | NH4BF4 is quite volatile. I kept it in an open container for drying and it covered inside walls of my cabinet.
I plan to use it for generate BF3 which have many interesting applications in inorganic as well as in organic chemistry. Also it's very potent drying
agent.
[Edited on 21-2-2024 by teodor] |
Sodium tetrafluoroborate can be used as well for this, does NH4BF4 work better? I'd like to make trifluoroacetic acid but I have found no other way
than to use antimony fluoride compounds.
|
|
|
EF2000
Hazard to Others
Posts: 154
Registered: 10-5-2023
Location: The Steppes
Member Is Offline
Mood: Taste testing the Tonka fuel
|
|
Gastrolobium calycinum is ~5 AU dollars for packet from Australian Seed: https://www.australianseed.com/shop/item/gastrolobium-calyci...
Gastrolobium bilobum is 6.5 USD for 10 seeds from rarepalmseeds.com, even though it's not rare and not a palm. And $14 for 1,000 seeds, meaning that for the price of 8 giftblaar seeds one can get
~2,500 poison brush seeds and plant an entire garden with it. Very toxic garden.
I also found a little instruction how to pre-treat seeds and sow them.
Attachment: Gastrolobium species.pdf (339kB)
This file has been downloaded 208 times
Wroom wroom
"The practice of pouring yourself alcohol from a rocket fuel tank is to be strongly condemned encouraged"
-R-1 User's Guide
|
|
|
Rainwater
National Hazard
Posts: 987
Registered: 22-12-2021
Member Is Offline
Mood: Break'n glass & kick'n a's
|
|
Side note, he is some dude spraying cold fluorine gas onto a fire brick (time index 11:12)
https://youtu.be/KX-0Xw6kkrc?t=672
"You can't do that" - challenge accepted
|
|
|
Dr.Bob
International Hazard
Posts: 2816
Registered: 26-1-2011
Location: USA - NC
Member Is Offline
Mood: Mildly disgruntled scientist
|
|
I did work in a fluorochemical synthesis lab for a few years with my old friend Ed, who was much more jaded about working with fluorine than most
people are today, having worked with it for 50+ years. But only long after working there did I realize how many things he had there were incredibly
toxic, like cylinders of F2, HF, SF4, and many others, plus some other things like monofluoroacetic acid and related compounds. But he was somehow
lucky, and I think the F2 just made him inert to all other chemicals, as he lived to be about 98.
But even Ed had Calcium Gluconate kits and other safety gear, plus some very large scrubbers which most of the gas streams went out through. Mostly
I worked with Freons, which are quite safe to handle, but the process of fluorinating hydrocarbons is quite exciting, and involves some very
specialized equipment.
I have also used anhydrous liquid HF for cleaving and deprotecting peptides, which is mostly not done any more now (mostly used for tBoc type peptide
chemisty, which is rarer now). That was almost as crazy, but done in special hood with special equipment, and 2 thick gloves, special aprons, face
mask, etc. That was just as nuts, and done in big pharma lab. I would not do it for fun or much else now. But I have done other fluorine type
chemistry that is safer and many fluoro groups are fine, like many, but not all, -CF3 type reagents. So the safety is quite dependent on the exact
type of chemistry, the equipment, and the real need to do it. Like making some fluorophosphates, minor changes can make drastic differences in
toxicity.
So I would say that some fluorine chemistry is quite safe, some is dangerous, and some is nuts. Even Ed tried to use ClF3 a few times and decided
that it was not able to be used safely for anything, depsite being a very powerful fluorinating agent.
[Edited on 26-3-2024 by Dr.Bob]
|
|
|
BromicAcid
International Hazard
Posts: 3266
Registered: 13-7-2003
Location: Wisconsin
Member Is Offline
Mood: Rock n' Roll
|
|
Had a very nasty experience with SF4 at one point Dr.Bob, always interesting to see people mention it since it tends to fly under the radar of most
chemistry.
|
|
|
bnull
National Hazard
Posts: 596
Registered: 15-1-2024
Location: Home
Member Is Offline
Mood: Sneezing like there's no tomorrow. Stupid cat allergy.
|
|
More stuff on fluorine and safety: the editorial by Trevor Laird, "Dangers of the Unknown" (https://pubs.acs.org/doi/10.1021/op034047r#), from Organic Process Research and Development, volume 7 issue 3.
|
|
|
Texium
Administrator
Posts: 4665
Registered: 11-1-2014
Location: Salt Lake City
Member Is Offline
Mood: Preparing to defend myself (academically)
|
|
| Quote: Originally posted by Dr.Bob | | I have also used anhydrous liquid HF for cleaving and deprotecting peptides, which is mostly not done any more now (mostly used for tBoc type peptide
chemisty, which is rarer now). That was almost as crazy, but done in special hood with special equipment, and 2 thick gloves, special aprons, face
mask, etc. That was just as nuts, and done in big pharma lab. I would not do it for fun or much else now. But I have done other fluorine type
chemistry that is safer and many fluoro groups are fine, like many, but not all, -CF3 type reagents. So the safety is quite dependent on the exact
type of chemistry, the equipment, and the real need to do it. Like making some fluorophosphates, minor changes can make drastic differences in
toxicity. |
The standard procedure the peptide chemists I know use is to deprotect Boc with TFA. Much safer.
|
|
|
chloric1
International Hazard
Posts: 1159
Registered: 8-10-2003
Location: GroupVII of the periodic table
Member Is Offline
Mood: Stoichiometrically Balanced
|
|
Anyone here ever work with hexafluorosilicates? It’s has interesting properties in being able to precipitate potassium and sodium from their salts
as was having soluble heavy metal salts.
I can get 1 L of 23% hexafluorosilicates for $25. Problem is it is not ad stable as BF4- and is more prone to hydrolysis. Furthermore, I’ve read
where some working in the electro refining of metals such as lead have moved to sulfamates as replacements for hexafluorosilicates. So if I ever pull
the trigger on H2SiF6 I assume it to be like HF or NH4HF.
Fellow molecular manipulator
|
|
|
Sulaiman
International Hazard
Posts: 3779
Registered: 8-2-2015
Member Is Offline
|
|
My conclusion
HF is too corrosive and TOXIC for home use.
_________________________________________________
I bought 500ml 55% HF anyway.
(I hope that was not too dumb of me,,,,tbd)
and
2kg calcium carbonate to fill my tertiary HF container
(a cylindrical ex-kitchen plastic tub)
(the primary container is the hdpe bottle with cap insert as received,
secondary containment is just a ziplock bag)
1kg each of magnesium nitrate and calcium nitrate for making a bucket full of 'antidote' solution
new Face mask, apron, thick neoprene and nitrile gloves
I still need more ppe for arms and feet so I've done very little with the HF so far.
I will work outdoors with a fan behind me
(tested method, it works - if there are no sudden blasts of wind)
My lab assistant Kevin will be present during any HF experiments.
PS my biggest concern is that I die leaving the HF for my family to deal with.
and on a lighter note:
I just moved home and the HF was personally transported by me, by car,
(together with my other hazardous materials)
- a slow journey 
and
Adding the tertiary containment with calcium carbonate seems to have prevented all HF gas leakage to the environment.
CAUTION : Hobby Chemist, not Professional or even Amateur
|
|
|
Precipitates
Hazard to Others
Posts: 152
Registered: 4-12-2023
Location: SE Asia
Member Is Offline
Mood: Acid hungry
|
|
I'm just surprised at how easily it can be purchased in SE Asia, there must not have been any major disasters, yet...
In any case, HF is way too intense for me
That's my biggest concern about my bromine, although wouldn't be my family, would probably be my landlord or someone* 
Anyway...please report your experiments...so I can be an armchair fluorine chemist!
*Worth noting, I definitely do not believe it would be a chemistry related death...more natural or a road traffic accident (roads are lethal here). I
can take precautions against chemistry related injury...crossing or walking along the street, or lorries pulling out in front of me whilst I'm
driving, not so much.
|
|
|
teodor
International Hazard
Posts: 1001
Registered: 28-6-2019
Location: Netherlands
Member Is Offline
|
|
| Quote: Originally posted by mr_bovinejony | | Quote: Originally posted by teodor | NH4BF4 is quite volatile. I kept it in an open container for drying and it covered inside walls of my cabinet.
I plan to use it for generate BF3 which have many interesting applications in inorganic as well as in organic chemistry. Also it's very potent drying
agent.
[Edited on 21-2-2024 by teodor] |
Sodium tetrafluoroborate can be used as well for this, does NH4BF4 work better? I'd like to make trifluoroacetic acid but I have found no other way
than to use antimony fluoride compounds. |
NaBF4 is better but I was curious about NH4BF4 because it could be synthesysed starting from NH4HF2 and as I said already NH4F and NH4HF2 I consider
as entry compounds for fluorine chemistry because they already have some danger properties of fluorine chemistry but still quite manageable, so
synthesis of NH4BF4 (by both cold and hot procedures) could be quite educative for novice F chemist.
The point is binding F to some other elements dims it wilde properties. It would be nice to have some scale of danger. B-F is more managable than F-F.
And everything come with experience which includes accuring a proper techniques and equipments. There are many interesting works with anhydrous HF and
obviously it is not my level. But what I red about BF3 make me think I have to try look at it before other F-<element> bonds.
My today's lab is not quite home lab anymore, I would say it becomes more semi-professional lab, so obviously I am interesting in extending the amount
of compounds I am comfortably can work with.
The interesting properties of NH4F is that with heating it loses nore NH4 than HF, the same is partially valid about NH4HF2. And you can see on its
melt as HF dissolved in anhydrous NH3. But in cold state they both are crystalls. So you can do many experiments the same way as you do with HF
solution in water just keeping in mind you have a different solvent system.
(The same way NH4BF4 is a solution of BF3 and HF in NH3, which makes it to be different from NaBF4. Also this salt is from the family of
oxidiser-reducer, F in it can oxidise ammonia ion at some conditions to nitrogen oxides, so you can start to explore oxidising properties of fluorine
with this compound).
[Edited on 4-2-2025 by teodor]
|
|
|
Sulaiman
International Hazard
Posts: 3779
Registered: 8-2-2015
Member Is Offline
|
|
I am a (insert swear word here) idiot !
Despite all of the sensible warnings
I bought 500ml of 55% HF.
In itself that is a rather risky choice,
but now it seems that I will not have a safe workspace for a long time.
Just storing it gives me nightmares when I'm awake.
Presently it is stored in its original hdpe bottle (with a cap insert)
The bottle is in a larger plastic tub, with 1kg of calcium carbonate.
I NEED TO DISPOSE OF 500ml OF 55% HF SOLUTION -SAFELY
just combining with any carbonate would, I expect, release CO2 producing a nasty mist.
I admit it ... I am 'unwise'...and ignorant
please help.
Not urgent..
______________________________________________
I have some equipment, chemicals and outdoor space, adequate ppe if upwind. (I use electric fans when required)
Rather than calcium gluconate gel I have kilogrammes of magnesium and calcium chlorides to make an antidote bath - just in case.
I will buy whatever else is required.
D'oh !
[Edited on 12-3-2025 by Sulaiman]
CAUTION : Hobby Chemist, not Professional or even Amateur
|
|
|
woelen
Super Administrator
Posts: 8080
Registered: 20-8-2005
Location: Netherlands
Member Is Offline
Mood: interested
|
|
First dilute it in a plastic bucket of water. Do this outside. E.g. put 7 liters of water in a bucket and then pour in the HF. Stir with a big plastic
bar.
Next, take a liter of lye (40% NaOH, you can buy that in many hardware stores) and slowly, while stirring with the plastic bar, pour in the bucket
with dilute HF.
You now have a solution of NaF. This, you can flush away in a toilet, provided it is connected to a good sewer system. All those millions of people,
brushing their teeth with tooth paste, containing 0.1% NaF or so, put more fluoride in the sewer system every day then you do with your 300 grams of
HF only once.
All this work should be done with good personal protection. Avoid spilling any of the liquid on your skin!!!
|
|
|
Fulmen
International Hazard
Posts: 1748
Registered: 24-9-2005
Member Is Offline
Mood: Bored
|
|
I can't find anything wrong with that reasoning. Perhaps dispose of it over a week or two if you're worried about the concentration setting off
alarms?
Or, just make CaF2 from it until you can resume the project?
We're not banging rocks together here. We know how to put a man back together.
|
|
|
Sulaiman
International Hazard
Posts: 3779
Registered: 8-2-2015
Member Is Offline
|
|
OK sounds good, no bubbling or thermal problems, so simple, I like it.
I would make up the hydroxide solution as I have NaOH, and use when cool,
I'll check the stoichiometry to ensure excess hydroxide
but probably make a larger quantity of less concentration.
Thank you both for clearing a path for me,
I am already less stressed.
Storing as CaF2 is a good idea
but I'm now unlikely to mess with fluorine in the future / ever.
I already have enough ways to harm myself.
Even if I get 99% prepared, it is not enough, considering potential consequences.
Hopefully this lesson has been learned in time.
CAUTION : Hobby Chemist, not Professional or even Amateur
|
|
|
Fulmen
International Hazard
Posts: 1748
Registered: 24-9-2005
Member Is Offline
Mood: Bored
|
|
I totally respect that.
We're not banging rocks together here. We know how to put a man back together.
|
|
|
teodor
International Hazard
Posts: 1001
Registered: 28-6-2019
Location: Netherlands
Member Is Offline
|
|
@Sulaiman, just dilute it to 20% concentration.
I am reading a book just now written by Otto Ruff, a famous fluorine chemist. He describes different burns from HF (definitely had experience) with
great details. Hi has this statement: "20% HF is totally harmless for fingers, provided its effect is not too prolonged" . Based on this and assuming
you always have protection, there is no reason for panic with 20%
|
|
|
Precipitates
Hazard to Others
Posts: 152
Registered: 4-12-2023
Location: SE Asia
Member Is Offline
Mood: Acid hungry
|
|
I think attitudes towards safety were probably more relaxed in the 1920's.
I would not be letting HF touch my fingers at any concentration.
Some more up to date reading:
Hydrofluoric Acid Burns
No concentration is safe - but quantity and duration of exposure is perhaps more relevant.
Attachment: Acute_hydrofluoric_acid_exposure_reported_to_Taiwa.pdf (146kB)
This file has been downloaded 13 times
Sure, 20% HF probably isn't going to kill you (unless you perhaps bathe in it), but it's not harmless.
With this being said, I would by no means panic - just neutralise as suggested above.
|
|
|
| Pages:
1
2
3 |
![[*]](images/xpblue/default_icon.gif){kind=icon}
