[boredcoat]

Tomorrow, Ill be synthesizing m-dinitrobenzene by nitration of nitrobenzene. Ive never seen anyone wear a respirator (is recommended - H284 on the label). Is everyone underrestimating the danger or am I overestimating the MSDS? (we are in the uni lab, fume hoods and gloves - occasional weighing and measuring point of boil and stuff outside of the fume hood)

thanks for the reply.

[Hunter2]

The question is what are the rules in your lab or school. Normaly all the safety measures has to take care. Which MSDS you referring. To do the synthesis you need nitrobenzene, conc. Sulfuric and fuming nitric acid.
If the synthesis takes place in an closed apparatus under the fume hood then it is safe. A respirator maybe is needed to fill in the chemicals.

[Borek]

Strange, H284 is "Chemical under pressure: May explode if heated".

I don't see how it fits here.

[rolnor]

fumehood is enough, if the fans are good and the fumehood is not wide open. but its good that you think of safety