[Myrddin]

What is marketed as pure ethanol, "Everclear", is really only 95% pure, alcohol has an affinity for water. The 100% stuff is called "absolute alcohol"

The water/alcohol mixture has a depressed boiling point that results in the 95% limit. To get to 100% you add benzene to the alcohol. That takes the last 5% of the water away, but makes the end product toxic for human consumption.

[HiTech RedNeck]

Wouldn't concentrated sulphuric acid also absorb the remaining water, without mixing with the alcohol?

[76834]

Thanks for the info.
Like I said previous, it's been awhile since I took chemistry.
Always thought it was made by progressive distallation.

[Myrddin]

The ethanol/water azeotrope boils off at 78.15 degrees C.

Little details from taking 2 years of organic chemistry in a 10 week summer cram course.

[redgolum]

The water/alcohol mixture has a depressed boiling point that results in the 95% limit. To get to 100% you add benzene to the alcohol. That takes the last 5% of the water away, but makes the end product toxic for human consumption.

A molecular sieve is what most places use now. Cyclohexane is to nasty to use. Very flammable. I used to work at a plant that made ethanol, and we had a few contractors that would sneak the stuff straight out of the sieves. Gave them one heck of a hangover.