HmmÉ
Nital is a go-to etchant for steels and it's 1% to 5% Nitric in ethanol or methanol. It is commonly used (and available for purchase) at 2% and 3%. The 20% must have been a typo in the literature.
There is an analog to Nital that is 10% nitric in methanol and it's used for etching pure cobalt. If you buy this etchant pre-mixed, it will commonly contain 5% water.
Thank you,
Yaritza Brinker
260.827.5402
From: ACS Division of Chemical Health and Safety <DCHAS-L**At_Symbol_Here**Princeton.EDU>
On Behalf Of Daniel Kuespert
Sent: Thursday, July 15, 2021 10:14 AM
To: DCHAS-L**At_Symbol_Here**Princeton.EDU
Subject: Re: [DCHAS-L] Nitric Acid Disposal
Acetic acid or acetic anhydride can explode with nitric acid if not kept cold. Experiments demonstrate that mixtures containing more than 50% by weight of nitric acid in acetic
anhydride may act as detonating explosives under certain conditions. An indication is given of the percentage mixtures of acetic anhydride-nitric acid which could be detonated using a priming charge and detonator.
National Fire Protection Association; Fire Protection Guide to Hazardous Materials. 14TH Edition, Quincy, MA 2010. 491-124.
A possibly-useful source; try googling "nitric acetic acid reaction" and you'll get quite a few references. I always look askance at nitric acid with any organic, just as you do.
Just because it's in the literature does not mean it's safe. It just means that the experimenters in question were lucky. I once worked on an incident in which the investigators reproduced an old Soviet metallurgical procedure involving
20% nitric acid in ethanol ("nital"). The only problem was that above 5-10% nitric acid is not stable in ethanol, according to Bretherick's. There was quite a mess in the lab; fortunately, no explosion.
Daniel Reid Kuespert, PhD, CSP
I had a question from one of the organic chemists here about how to store the waste from a nitration using nitric acid in a dichloromentane/acetic acid solvent. He says there are several examples of this nitration in the literature, but
I am still wary. While the reaction is open to the atmosphere, I am worried about storing it until it can be disposed of. Any advice would be greatly appreciated.
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