[polyol]

Ethylene glycol, C₂H₆O₂, (1,2-ethanediol) is produced by the addition of an H₃O⁺ ion to ethylene oxide, C₂H₄0, (1,2-epoxyethane).  The boiling point of ethylene glycol is 196-198C.  When reagant grade ethylene glycol (>99.9% purity) is heated to 100-110C  any H₂O in the ethylene glycol is boiled out.  Theoretically. should there any other gaseous products?  Is this an efficient way of removing impurities from ethylene glycol?  Ethylene glycol is mixed with a metal acetate, M(CH₃CO₂)_n, (e.g. Co(CH₃CO₂)₂) and rapidly heated using a 2.45 GHz microwave source to temperatures around 240C.  The solution is under 30 PSI of pressure to prevent the solution from boiling.  A proposed mechanism suggests that dehydration of ethylene glycol occurs with the rapid heating and acetaldehyde, C₂H₄O, (ethanal) along with water is produced.  Acetaldehyde has a boiling point of 20.16C.  The acetaldehyde reacts with metal acetate to produce nanopahse metal particles.  In the presence of a metal oxide instead of a metal acetate, the acetaldehyde is oxidized to produce diacetyl, C₄H₆O₂, (2,3-butanedione) water and the metal.  Is diacetyl also formed when a metal acetate is used?  Once the percipitate is centirfuged can the remaining solution be distilled/purified back to ethylene glycol?  How is this accomplished?