The preparation of Glyoxal

Glyoxal , its CAS NO. is 107-22-2, the synonyms are 1,2-Ethanedione ; Aerotex glyoxal 40 ; Biformal ; Diformyl ; Ethanedial ; Glyoxylaldehyde ; Oxal ; Oxalaldehyde .

Commercial glyoxal is prepared either by the gas phase oxidation of ethylene glycol in the presence of a silver or copper catalyst or by the liquid phase oxidation of acetaldehyde with nitric acid. Global nameplate capacity is ~220,000 tons, with production rates less, due to over-capacity mostly in Asia. Most production is done via the gas phase oxidation route.
The first commercial glyoxal source was in Lamotte, France, started in 1960 and currently owned by Clariant. The single largest commercial source is BASF in Ludwigshafen, Germany at ~60,000 tons/annum. Only 2 production sites (Geismer, LA and Charlotte, NC) exist in the Americas. Significant recent capacity has been added in China. Commercial bulk glyoxal is made and reported as a 40%-strength solution.
Glyoxal is prepared in the lab by oxidation of acetaldehyde with selenious acid.
The preparation of anhydrous glyoxal entails heating solid glyoxal hydrate(s) with phosphorus pentoxide, as described in 1907 by Harries and Temme: "one heats the mixture of (crude) glyoxal and P4O10 with an open flame and soon observes that, upon blackening of the contents, a mobile green gas, which condenses in the cooled flask as beautiful yellow crystals)."