Fetid Fluids

Chemists often have to deal with chemicals of unpleasant nature, and fouls smells is a common feature of chemicals. On the other end, some truly dangerous ones, like benzene, have a not unpleasant smell.

Luckily these days I do not have to work with the mean amines or the dreadful mercaptans; in fact surfactants have mild, soapy smells for the most part.

But for reasons that shall remain obscure, I am also working with biodiesel. And that has been a surprise, in negative.

I expected biodiesel to have a mild smell like vegetable oil, but I was wrong. Maybe it's just the particular sample I got that has something wrong, maybe others have better aroma.

This one is evil instead. It smells of stale cheese - or more precisely, of the wooden shelves on which cheese is left to age and become impregnated with the oils and fluids exuding from the cheese.
Then the smell proceeds with vegetable oil effluvia - not the mild ones of clean, fresh oil, but potent vapors of not quide rancid, but almost there, oil.
And to top it off there is a note of sweaty feet, not sharp but pervasive. Lovely, eh?

The other unpleasant stuff I am dealing with is crude oil. It comes in many different varieties, but the ones I have are dark brown in color.

The light crude is not bad, it is a thin liquid that looks like very dirty kerosene and has that kind of hydrocarbon smell.
Heavy crude instead is meaner. It is viscous and sticks inexorably to all surfaces; at room temperature it is not smooth but contains a number of tiny lumps (of heavy hydrocarbons, I surmise).
The smell is not so bad at least, like used motor oil, hydrocarbons well cooked at high temperature while coming in contact with some air.

But I wouldn't like to breathe all day long crude oil vapors: as people who respond to oil spills can attest, it's no fun at all.