Sciencemadness Discussion Board

Seperating acetic acid from ethanol

Tao - 10-6-2013 at 16:22

Using a simple conversion of an ethanolic substance to acetic acid utilizing Acetobacter aceti, there of course will still be traces (or greater) of ethanol. What is the most practical & effective way to seperate pure acetic acid from the mixture? I suppose just go with a generic distillation apparatus?

Tao - 10-6-2013 at 16:24

Also, a problem I foresee is the flammability/combustibility of pure acetic acid. What precautions need to be taken for this?

Panache - 12-6-2013 at 08:06

Neutralise the acetic with sodium hydroxide, ensuring you add only the correct mass of NaOH to affect the neutralisation, distill/evaporate/boil off the ethanol, when the mush gets to approx 100C, apply a slight vacuum to remove residual ethanol, acidify with your choice of mineral or organic acid, distill off the acetic.
There is a decent thread on making glacial acetic from around 12 months back, another member used MgSO4 on wet acetic acid in dcm to remove the pesky water (an unfortunate byproduct of neutralising the sodium acetate with the acid.)
You could also look into the separations of the two chemicals under full vacuum, often strange azeotropes are established allowing separations not possible at atm pressure (eg the distillation of dry ethanol from the 96% azeotrope).
There may also be a standard simple azetrope that allows for the removal of the ethanol, perhaps toluene. i don't have my crc on hand, but scan through the ethanol azetropes, you may find a solution there.