Chlorophyll can be removed from leaves by boiling them in alcohol, a flammable solvent. In addition to wearing safety goggles, what other safety procedures should be taken?

1 Answer
Jan 1, 2017

No #"nekkid"# flames..........


Typically, a chemist would use a heating mantle (mind you, these still could be a source of ignition).

Note that ethyl alcohol is not terribly flammable, and I would feel much safer heating this solvent, than using say pentane or diethyl ether in a still (which is still commonly done).

Such flammable solvents are typically distilled under an argon or dinitrogen atmosphere. Of course, you need to have the glassware and plumbing to do this - laboratory stills are often run under a slow bubble of argon or nitrogen gas. Why would the fact that you have to pass water thru the condenser on the still (above sodium or potassium metal) be a significant hazard? Where these stills are permanently set up, the plumbing is usually installed with a float switch, so that if water pressure fails, the stills turn off.

In recent years, drying towers have become available (some even commercially), where a solvent is forced under pressure to go thru a tower of molecular sieves (i.e. drying pellets, with holes inside them that fit the water molecule). Where chemists need very dry solvents, they continue to utilize stills.