Nippon Shokubai Co., Ltd.

Akihiko Ohta

Noboru Saito

Yoshitaka Arita

Kimio Ariyoshi

Ren Hasebe

Alkylene glycol is oxidized in a vapor phase in the presence of alcohol (a), oxygen, and a catalyst (a) (primary reaction). &agr;-oxoaldehyde, and alcohol (b) or olefin, are oxidized in a vapor phase in the presence of oxygen and a catalyst (b) (secondary reaction). A molar ratio of the alkylene glycol to the alcohol (a) is preferably in a range of 1/100 to 5/1. It is preferable that one same compound is used as the alcohol (a) and the alcohol (b). In the case where the primary and secondary reactions are successively executed, a reaction device in which a primary reactor and a secondary reactor are connected in a two-stage connection type is preferably used. This ensures that a method is provided that is capable of producing &agr;-oxoaldehyde at a higher yield than conventionally, and further, that is capable of stably obtaining an &agr;-oxoaldehyde solution or gas with a higher concentration than conventionally.

Process for the preparation of alpha-oxoaldehydes

A method of manufacturing .alpha.-oxocarboxylate includes the steps of: (i) carrying out a vapor phase oxidation of 1,2-diol of formula (1) in a primary reaction vessel, (ii) introducing a resulting gaseous .alpha.-oxoaldehyde and/or .alpha.-hydroxyaldehyde in a secondary reaction vessel together with alcohol or olefin which is converted into a gas form in a vaporizing chamber, and (iii) carrying out an oxidative esterification of the gaseous .alpha.-oxoaldehyde and/or .alpha.-hydroxyaldehyde molecular oxygen in a presence of inorganic oxide containing phosphorus as a catalyst in the secondary reaction vessel, ##STR1## (R is a hydrogen atom or an organic residue). The described method permits .alpha.-oxocarboxylate to be manufactured economically and effectively in practically one step using inexpensive 1,2-diol such as ethylene glycol or propylene glycol.

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Suita, Japan

Akihiko Ohta