Distillation Theory

Distillation is a process that involves heating a liquid such as water, petroleum or some other mixture and heating the different materials to their boiling points.  Interestingly, some materials boil at different temperatures. For example:

Alcohol--grain ( 174 degrees F)

Alcohol--wood (151 degrees F)

Ether (95 degrees F)

Esters (around 170 degrees F depending on the kind)

Mercury  (675 degrees F)

Petroleum (410 degrees F)

Water (212 degrees F)

When a material boils, it creates gas vapors that are sent off as hot steam. In order to trap these vapors, the material must be temperature controlled so that only one liquid will boil at a time.  

The laboratory scientist must collect the vapor and cool it back to a liquid (condense it). The process of boiling and condensing is called distillation.  A typical apparatus for distillation looks like the drawing below:

The hot gas enters a tube surrounded by cool water, called a condenser. The gas condenses back to a liquid and is collected as the "distillate."

If the temperature is just right, only certain liquids will boil, turn to a gas and then be collected as a liquid.

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