Working with anhydrous hydrogen fluoride.

AHF (Anhydrous Hydrogen Fluoride) is a really nasty thing, it boils at 19.5 °C, it causes nasty burns and could easily kill you if you something unexpected happens. Upon contact with moisture, including tissue, hydrogen fluoride immediately converts to hydrofluoric acid, which is highly corrosive and toxic, and requires immediate medical attention upon exposure. Breathing in hydrogen fluoride at high levels or in combination with skin contact can cause death from an irregular heartbeat or from fluid buildup in the lungs.

So how can we work with this thing?

Since it has a low boiling point, it could be transferred from the gas cylinder (third pics) to the teflon reaction vials by condensing it by cooling it under it’s boling point. In this case for this we used dry ice what cools the walls of the vial to −78.5 °C wher the AHF turns into a liquid. When the required amount of AHF is condensed into the teflon vial, it is closed and when the reaction ready, the excess AHF is removed by vacuum.

As seen every part of this thing above is made from Teflon or steel. This two is resistant to AHF, but if I would work with this in a glass container the AHF would react with it to form SiF4 and dissolve the whole apparatus in no time.

9:30 pm • 18 May 2015 • 139 notes • View comments