[tiff8968]

In lab we were doing fermentation of sucrose to get ethanol. Everything was going great (vacuum filtration, simple distillation) until I got to fractional distillation. Ethanol has a boiling point of 77-80 degrees celsius which means start distilling at during that range. Well, my ethanol solution didn't start distilling until it reached 96 degrees celsius. I wasn't the only one who had this problem but almost everyone in the class. My question is what could have caused my ethanol solution to distill at 96 degrees instead of 77-80?? I can't think of anything and I followed all the steps....

[azmanam]

where was the thermometer bulb?  was it at the junction point of the reflux condenser and the distillation arm?  was it in the ethanol solution?  Was it pushed in too far and was it below the junction point?  Was it in the (water/sand/oil) bath?  Was your fractional distillation column too short? 

[James Newby]

It could be that the ethanol wasnt pure.  A mixture of ethanol/water would boil at a higher temperature.

http://www.chemguide.co.uk/physical/phaseeqia/nonideal.html