Alcohol Distillation Safety
Status: educator assistant
Date: March 2008
I am the CHO/Science Assistant for our 9-12 grade high
school. We are doing fractional distillation of alcohol in General
Chemistry using 50 ml of an isopropyl alcohol solution, hot plates,
flasks, and condenser tubes, etc. with Vernier temperature probes.
We have tried a 10% and a 30% isopropyl solution but the graphing
results are rather vague. With 70% rubbing alcohol, the graphs are
easy for the students to understand. Are we safe in using this
strength? No open flames, supply bottles capped...
most are not. A steam bath would be a better source of heat. If "nothing goes
wrong" you may have no problem, but if a boiling flask breaks you could have
70% isopropanol vapor coming into contact with the circuitry inside the hot
plates. A fire could result. In planning an experimental procedure the rule
is to run through the procedure step-by-step and ask the question, "What can
happen here that would be bad, and if it happens, what will I do?" Always
apply Murphy's Law.
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Update: June 2012