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|Section2= |Section3= |Section4= |Section5= }} Glyoxal is an organic compound with the formula OCHCHO. It is a yellow-colored liquid that evaporates to give a green-colored gas. Glyoxal is the smallest dialdehyde (two aldehyde groups). Its structure is more complicated than typically represented because the molecule hydrates and oligomerizes. It is produced industrially as a precursor to many products.〔Georges Mattioda, Alain Blanc, "Glyoxal" in Ullmann's Encyclopedia of Industrial Chemistry, 2005, Wiley-VCH, Weinheim. 〕 ==Production== Commercial glyoxal is prepared either by the gas-phase oxidation of ethylene glycol in the presence of a silver or copper catalyst (Laporte process) 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. The single largest commercial source is BASF in Ludwigshafen, Germany, at ~60,000 tons per year. Other production sites exist also in the US and China. Commercial bulk glyoxal is made and reported as a 40%-strength solution in water. Glyoxal may be synthesized in the laboratory by oxidation of acetaldehyde with selenious acid. The preparation of anhydrous glyoxal entails heating solid glyoxal hydrate(s) with phosphorus pentoxide and condensing the vapors in a cold trap. The experimentally determined Henry's law constant of glyoxal is: KH = 4.19 × 105 × exp(× 103/R) × (1/T − 1/298) ). 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Glyoxal」の詳細全文を読む スポンサード リンク
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