Re: pirahna solution



muha schreef:
> Here is how to make the solution. 1) Hood with glass down, googles,
> good gloves. If you are using thin latex gloves, double them.
> 2) Remove all flamables. The mix explodes in contact with acetone and
> other solvents. Remove stuff around, there may be some spilling. The
> stuff ignites paper, so be carefull with wiping it out. Let the mix
> expire overnight before cleaning the spill. Wash the whiping towels
> immediately with water to avoid their self-ignition.
> 3) Use large beaker to avoid overheating and spill because of
> foaming-over. Take a large (1L) beaker with conc. H2SO4 150mL. Put the
> hood glass down, add 30% H2O2 50 mL INTO the sulfuric acid (I know, but
> believe me, this is the right order), mix it by gentle swirling the
> beaker. At this point the mix becomes hot and bubbling. Use fresh
> immediately. Leave the waste mixture in hood overnight to expire before
> diluting it with ice water. Pour it to waster waste after diluting it,
> never into organic waste.
>
> We use this mix to clean up dirty fritted filtration funnels. Again,
> the glassware must be free of organic solvents to avoid fire or
> explosion.
>
> Never make it in larger amounts, never store it but allways use fresh,
> never work with it outside hood. If you want to know what would happen
> to your face, you can drop a very small bit of paper into the mix and
> watch it disappear in a puf of smoke as soon as it hits the mixture.

Wouldn't it be REALLY hazardous to have almost 200 ml of this stuff
around? I once did an experiment by mixing approximately 0.2 ml of
H2SO4 with 2 big drops of 30% H2O2 on a clean glass surface. I did not
do this in a fume hood, but in a normal room. I saw little specks of
light sometimes, probably because small dust particles, entering the
liquid immediately were oxidized with evolution of a lot of heat. Next,
I took a *** of paper and put this on the liquid. It immediately went
BOOM/CRACK and there was a hole in the *** of paper. Luckily no fire,
but that was my last experiment with concentrated H2O2/H2SO4 mixtures!

Wilco

.