Distillation of Alcoholic Beverages?

Question

When you perform distillation or boiling point determination, why is it not advisable to place/submerge the thermometer in the liquid?

Also, if you have a mixture of 50/50 ethanol and isopropyl alcohol, would you recommend using simple distillation to separate the two liquids? Why or why not?

Answer 1

Different parts of the liquid might be different temperatures (eg. the bottom is hotter than the surface), so the temperature of one part of the liquid might not be the same as that of the vapor coming off it - and it is this temperature that determines the concentration of the compounds in the vapor.

For ethanol and isopropanol, ethanol boils at 78.4 C and isopropanol at 82.3 C.  This is a rather small temperature difference, so I doubt a simple distillation would be very effective in separating the two.

Answer 2

Actually

Different parts of the liquid might be different temperatures (eg. the bottom is hotter than the surface), so the temperature of one part of the liquid might not be the same as that of the vapor coming off it - and it is this temperature that determines the concentration of the compounds in the vapor.

For ethanol and isopropanol, ethanol boils at 78.4 C and isopropanol at 82.3 C. This is a rather small temperature difference, so I doubt a simple distillation would be very effective in separating the two.