Acyl halides pyrolysis

Imidazolium halides pyrolysis, 5, 449 Imidazolium ions acylation, 5, 402 H NMR, 5, 352 hydrogen exchange, 5, 417 nucleophilic attack, 5, 375 reactivity, 5, 375 ring opening, S, 375 Imidazolium oxides in pyrrole synthesis, 4, 344 Imidazolium perchlorate, 1,3-diphenyl-acylation, 5, 402 Imidazolium salts 1-acetyl-... 

Pyrolysis of carboxylic acids Dehydrohalogenation of acyl halides Dehalogenation of a-halo acyl halides Rearrangement of diazo ketones (Wolff)... 

The oldest method for the formation of a ketene, used by Staudinger in his studies on diphenylketene, is the reduction of an a-haloacyl halide with activated zinc. Most often, the ketene components used in the Staudinger reaction are usually produced by either of two ways the elimination of an acyl chloride (or less frequently another activated carboxyl derivative) in the presence of a base, or the Wolff rearrangement of a-diazocarbonyl compounds.The ketene is usually generated in situ in the presence of the imine however, if the ketene is stable enough, it may be prepared separately and then introduced into reaction with the imine. Other methods to produce ketenes have been used less often in the Staudinger reaction due to incompatibility with the imine component or p-lactam product or due to the harsh conditions required, such as the high temperatures employed in the pyrolysis of acid anhydrides or ketone acylals. 

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