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Author: Subject: Why is acetonitrile considered a hazardous material?
Melgar
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[*] posted on 8-6-2017 at 04:11
Why is acetonitrile considered a hazardous material?


I see data sheets all the time saying it's "EXTREMELY HAZARDOUS", and yet I could easily take a shot of it and be just fine. (LD50 is something crazy like 2g/kg) Is it due to the fact that if it burned, cyanide vapors could be released? Doubtful, because that's true of anything that's made up of hydrogen, carbon, and nitrogen, plus acetonitrile burns completely and easily when there's enough oxygen for it to do so.

Until proven otherwise, I'm going to assume that some dumbass in congress heard acetonitrile's alternate name, "methyl cyanide" and thought "holy shit, it's like a combination of meth and cyanide, how could it NOT be dangerous!?"
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clearly_not_atara
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[*] posted on 8-6-2017 at 08:53


Maybe it has to do with corrosion/complexes forming with metals? I know it complexes Pd/Ag/Cu so it probably complexes some other metals too. Also if it self-condenses (upon reaction with a base or possibly a metal like Mg? At high temperature?) the product is cyanoacetone imine which I think can release cyanide more easily.
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[*] posted on 8-6-2017 at 11:41


Burning is not necessary, it is also metabolised to cyanide in your body.
If that were a large problem, you'd expect the LD50 to be lower though. Are you sure about it? Could it be that the value you mention is for a non-human species that is more resistant to it?




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[*] posted on 8-6-2017 at 16:47


Quote: Originally posted by Melgar  
I see data sheets all the time saying it's "EXTREMELY HAZARDOUS", and yet I could easily take a shot of it and be just fine. (LD50 is something crazy like 2g/kg) Is it due to the fact that if it burned, cyanide vapors could be released? Doubtful, because that's true of anything that's made up of hydrogen, carbon, and nitrogen, plus acetonitrile burns completely and easily when there's enough oxygen for it to do so.

Until proven otherwise, I'm going to assume that some dumbass in congress heard acetonitrile's alternate name, "methyl cyanide" and thought "holy shit, it's like a combination of meth and cyanide, how could it NOT be dangerous!?"


The Extremely Hazardous tag applies to any chemical regardless of their toxicity, if it has other physical hazards. Acetonitrile may not be very toxic, but with a flash point of 2 degrees celsius and a boiling point of 82 degrees, it would be a class 1B flammable liquid, and thus be considered to be Extremely Hazardous.
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PirateDocBrown
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[*] posted on 8-6-2017 at 17:43


Its NFPA is only 2 for Health, but 3 for Flammability.
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BromicAcid
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[*] posted on 8-6-2017 at 18:24


Remember, LD50 is only a part of the story. Acetonitrile is far from health food. I certainly wouldn't take a shot of it.

Quote:

/CASE REPORTS/ The case of a 39-year-old woman, who was found vomiting and confused 7 hr after ingesting 59 mL of nail polish remover (/SRP: probably nail glue remover not nail polish remover/) containing 99% acetonitrile (4 g/kg) /was reported/. About 12 hr after ingestion, she developed severe metabolic acidosis, seizures and shallow respiration. Eight hours after ingestion she had a whole blood cyanide level of 3130 ug/L. At 65 hr the serum cyanide level was 10 mg/L and thiocyanate was 120 mg/L, whereas at 77 hr they were 12 mg/L and 30 mg/L, respectively. She responded to the treatment with sodium nitrite and sodium thiosulfate. Although she had several relapses, each time she responded to sodium thiosulfate administration. On the fifth hospital day the cyanide level was 360 ug/L and thiocyanate level 30 mg/L and the patient was discharged on day six.

/CASE REPORTS/ A case of acute acetonitrile intoxication in a 26-year-old man who ingested 40 g of acetonitrile in a suicide attempt /was reported/. After a 3 hr latent period, he suffered from vomiting, convulsions, coma, acute respiratory insufficiency, severe metabolic acidosis, and two cardiac arrests. In addition to supportive treatment (oxygen, mechanical ventilation, correction of shock and acidosis), dicobalt EDTA, sodium nitrite, sodium thiosulfate and hydroxocobalamin were also administered. His clinical course was complicated but he fully recovered 3 months later.


https://toxnet.nlm.nih.gov/cgi-bin/sis/search/a?dbs+hsdb:@te...

I have been told on various occasions that acetonitrile is much more dangerous to people who drink regularly, their bodies apparently generating cyanide more rapidly,.




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Melgar
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[*] posted on 9-6-2017 at 12:00


It still seems like the only people who were poisoned by it were clearly suicide attempts or very small children whose parents left them unsupervised near dangerous chemicals. It hardly seems to justify charging a $25 hazmat fee to ship less than a liter of it, when plenty of things with similar properties, like ethylene glycol and acetone, don't have the same hazmat designation.
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byko3y
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[*] posted on 9-6-2017 at 13:57


In my reagion I was shipped with acetonitrile without any hazmat fee. They ship it just like a petroleum ether or ethanol, which are both highly flammable.
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BromicAcid
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[*] posted on 10-6-2017 at 06:37


Why is acetonitrile considered a hazardous material? Because it is.

It hits the marks for the definition that has been set fourth for a hazardous material for the DOT (I will be talking US regs since that is what I know). I figure you are most interested in that criteria since you bemoan the hazmat shipping fee.

Acetonitrile ships as a hazard class 3 (flammable) packing group II (middle of the pack) material. It does not have a poison (6) subsidary hazard class so that isn't part of the equation. The determination here is based on flammability which is determined quantitatively. You mention acetone not being the same hazmat designation, actually it has an identical hazmat designation - hazard class 3, packing group II. Packing group for flammable materials is determined by their flashpoint:

https://en.wikipedia.org/wiki/HAZMAT_Class_3_Flammable_liqui...

Essentially packing group I is the most stringent with III being the least stringent. This determines which sort of box/overpack the unit needs to go into.

The critical thing with all of this, is that shipping regs are not meant to protect you. They are meant to protect all the people involved with sending your purchase from seller to buyer. That is why a properly shipped box will have large visible placards on the side. That is why a hazardous material will ship on a manifest. If the unit falls off a shelf or is leaking the person transporting it should be able to quickly identify the hazards and respond. If the truck is in a wreck they should be able to look at the shipping papers and see what issues might manifest. This is the extra level that hazmat shipping provides. And if you're in denial about the flammability hazards then you've never something catch fire from vapors that had traveled to some far away ignition source.

Sometimes things get muddled because you run into hazardous chemicals all the time in day to day life but don't see special precautions taken with them. But more often than not those chemicals do come to the distributor as hazardous materials.




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Melgar
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[*] posted on 10-6-2017 at 12:51


Thanks for answering the question. I figured it had to do with flammability, although for 500 mL, you'd think the danger would be minimal. I guess I made the stupid mistake of assuming that eBay kept on top of these things; acetone there is listed at prices indicating the shippers clearly aren't paying hazmat fees. So are plenty of other chemicals.

I'm fully aware that hazmat fees are to protect whoever is transporting the material; to think otherwise would make no sense. My comments about its toxicity were simply there to rule out toxicity as the reason for the hazmat designation.




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BromicAcid
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[*] posted on 10-6-2017 at 13:29


Most SDS sheets will list the shipping name at the bottom along with the hazard class so you can do a quick check.



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Melgar
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[*] posted on 10-6-2017 at 20:22


Yeah, I guess my confusion came from the fact that for some reason, acetonitrile seems to be the only solvent that all sellers seem to be complying with hazmat restrictions for. That part is still confusing. I can get THF, hexane, and ethyl acetate for a lot cheaper than acetonitrile, and all of those are similar as far as flammability.

Thinking about it though, diethyl ether is also really hard to find for a reasonable price, but it can be distilled from starting fluid or substituted with THF, so it's not as important.

[Edited on 6/11/17 by Melgar]




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