Wednesday, April 4, 2012

Process Wednesday: active HF decontamination solutions

Reading through the latest issue of the Journal of Chemical Health and Safety, I'm terribly interested by an article [1] describing a proprietary "active decontamination" solution for working with HF called Hexafluorine. See the results here:
A  70% HF facial vapor exposure occurred in a French industrial facility that manufactures glass and crystal. Since 1972, this facility has used about 240 tons of HF per year. Personnel who work on the HF line are trained about ht ahzards and risk of HF and HF splash decontamination... After 1993, Hexafluorine (Laboratoire Prevor, Valmondois, France) was used instead of water as the initial decontamination solution and calcium gluconate was only used when necessary to treat actual HF burns. 
A 35-year-old technicians was exposed to 70%  HF vapor on the right cheek (approximately 1-2% total body surface area) when opening a valve in the hydrofluoric acid circuit. He immediately felt severe pain in the exposed area. Safety goggles were worn, so no eye exposure occurred. The worker immediately decontaminated himself with a Hexafluorine 5-liter high volume / low pressure portable shower, after which he rapidly became pain-free. 
On medical examination in the facility infirmary, there were no clinical findings other than mild, painless erythema of the exposed area. Topical treatment with 3% calcium gluconate was initiated the day following the exposure as some residual painless erythema was still present. During the following week and at 1 month post-exposure, the worker was re-examined in the facility infirmary and no sequelae were noted. There was no lost work time.
Hey -- that sounds like success! What is Hexafluorine, anyway? Well, nobody's talking:
The name "Hexafluorine" is a registered trademark of the manufacturer (Laboratoire Prevor, Valmondois, France) who consider the general chemical name and formula to be confidential proprietary information. It is a sterile, aqueous solution containing amphoteric and chelating salts. Hexafluorine is only supplied in one concentration and is a clear and colorless liquid with a specific gravity of 1.046 g/m3 and a pH of 7.2-7.7. Specifically, Hexafluorine does not contain 6 fluorine atoms; rather, it has specific binding sites for both the H+ and F- ions of HF. 
Some kind of amine solution, maybe? I doubt the existence of Hexafluorine will put HF solutions into the tool kit of the typical manufacturing-scale chemist -- that said, it's interesting and worth knowing about its existence.

1. Siéwé, C.-L.; Barbe, J.-M.; Mathieu, L.; Blomet, J.; Hall, A.H. "Hexafluorine decontamination of 70% hydrofluoric acid (HF) vapor facial exposure: Case Report." Journal of Chemical Health and Safety. 2012, 19, 7- 11. doi: 10.1016/j.jchas.2011.05.011

9 comments:

  1. Just googling a little bit for fluoride chelation suggests that various boran compounds are used. Regardless, it still seems to be very effective and I'm glad to hear it as usually HF burns lead to something like this.

    (In case the hyperlink isn't active: http://www.nejm.org/doi/full/10.1056/NEJMicm055763)

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  2. Looks like hexafluorine could be EDTA and Aluminum Nitrate?
    French patent FR2604900 "Physiological solution for washing parts of the human body which have come into contact with hydrofluoric acid and concentrate for preparing it"
    http://worldwide.espacenet.com/publicationDetails/claims;jsessionid=E8A857FD2FE5085A8F618F06A0BA53E0.espacenet_levelx_prod_3?CC=FR&NR=2604900A1&KC=A1&FT=D&ND=&date=19880415&DB=&&locale=en_EP

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  3. Relevant I guess:
    http://www.ncbi.nlm.nih.gov/pubmed/15461243
    "CONCLUSION:
    In this experimental study, decontamination with Hexafluorine was not more effective than water rinsing in reducing electrolyte disturbances caused by dermal exposure to hydrofluoric acid."

    Poor rats though.

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    Replies
    1. It appears that the JCHAS article appears to be the latest salvo between the Hexafluorine articles and the Swedish group above. Here's a response from the HexF people to the above cited Swedish paper: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3116720/?tool=pubmed

      I suppose it boils down to this: if you work with 70% HF, you need to have decided already what the appropriate treatment is. It sounds like you have less than 3 minutes before damage sets in.

      Pop quiz, hotshot -- what are you going to do?

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  4. Every time I worked with HF, I considered eating a tube of Calgonate just as a precaution.

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  5. Uh, does having "specific binding sites for both the H+ and F- ions" make much sense when the pKa is only 3 or so?

    Conventional wisdom is that HF is deadly because it doesn't dissociate. It makes its way through tissue and bone all the time making insoluble CaF2.

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  6. Shouldn't you have to disclose the contents of your product/drug/treatment in order to be published in a scientific journal? Otherwise, how can the product be evaluated thoroughly?

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  7. Doesn't look like HEXAFLUORINE® solution is commercially available in the US. What is that all about?

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