KETENES, in chemistry, a group of organic compounds which may be considered as internal anhydrides of acetic acid and its substitution derivatives.
Two classes may be distinguished: the aldo-ketenes, including ketene itself, together with its monoalkyl derivatives and carbon suboxide, and the keto-ketenes which comprise the dialkyl ketenes.
The aldo-ketenes are colourless compounds which are not capable of autoxidation, are polymerized by pyridine or quinoline, and are inert towards compounds containing the groupings C :N and C :O.
The ketenes are usually obtained by the action of zinc on ethereal or ethyl acetate solutions of halogen substituted acid chlorides or bromides.
It differs from the simple ketenes in that it is apparently unacted upon by phenols and alcohols.