Glyoxal

"Glyoxal is an organic compound with the formula OCHCHO. This yellow colored liquid is the smallest dialdehyde (two aldehyde groups). Its tautomer acetylenediol is unstable."

"Glyoxal may be synthesized in the laboratory by oxidation of acetaldehyde with selenious acid.^[1] The preparation of anhydrous glyoxal entails heating solid glyoxal hydrate(s) with phosphorus pentoxide and condensing the vapors in a cold trap.^[2] The experimentally determined Henry's law constants of glyoxal is: K_H = 4.19 × 10⁵ × exp[(62.2 × 10³/R) × (1/T − 1/298)]"