[LabRat01]

Here's something I don't understand: 

Potassium cyanide, -OSHA Permissible Exposure Limit (PEL):
5 mg/m3 skin (TWA) (as CN)

vs.

Methyl Vinyl ketone, 0.1 mg/m3 TWA

Now, potassium cyanide can kill you in mg amounts, but  why is MVK'S PEL so low?

[OC pro]

It is simply much more toxic. It is a strong alkylating agent and Michael acceptor that binds to cellular protein sulfhydryl groups and glutathione (GSH).

Reported toxicity data for MVK include: an oral LD50 of 30 mg/kg in the rat; an oral LD50 of 33 mg/kg in the mouse; an inhalation LC50 of 7 mg/m3/4h (2.4 ppm/4h) in the rat and inhalation LC50 of 8 mg/m3/2h (2.8 ppm/2h) in the mouse.

Really nasty stuff. Compared to this KCN is easy to handle. I did once a cyanation with >100g of KCN. That was a bit scary.

[LabRat01]

It is simply much more toxic. It is a strong alkylating agent and Michael acceptor that binds to cellular protein sulfhydryl groups and glutathione (GSH).

Reported toxicity data for MVK include: an oral LD50 of 30 mg/kg in the rat; an oral LD50 of 33 mg/kg in the mouse; an inhalation LC50 of 7 mg/m3/4h (2.4 ppm/4h) in the rat and inhalation LC50 of 8 mg/m3/2h (2.8 ppm/2h) in the mouse.

Really nasty stuff. Compared to this KCN is easy to handle. I did once a cyanation with >100g of KCN. That was a bit scary.

Hmm, interesting, I thought that KCN could kill you at 2.2 mg/kg bodyweight....isn't it more potent than MVK?

Anyway, I suspect MVK isn't THAT bad, by bad I mean toxic and carcinogenic, surely Acrolein and Crotonaldehyde are worse!

[LabRat01]

I forgot to mention that I used about 5g of KCN today, and I could smell the HCN even though it was about 40 cm from the edge of my fumehood.

Really strange smell, but my lab colleague couldn't smell it.. I was supposed to do my reaction with 20 g of KCN but my supervisor said it was a little too dangerous, so now I must do the reaction 4 times >.<


I must have changed my gloves about 10 times, washed my hands 10 times and changed my labcoat twice 

[408]

My Supervisor keeps a couple hundred grams of frozen HCN for whenever it is needed 

[nj_bartel]

Mine does the same type of stuff.  Not fun!

[azmanam]

also, i suspect the higher limit for KCN might be a factor of measuring skin exposure.  It's a salt, if you got a bit on your skin and removed it, I don't think it would be as damaging as ingesting it or getting HCN on your skin.