The dry distillation of calcium acetate to give acetone was reported by Charles Friedel in 1858 and until World War I ketonization was the premier commercial method for its production.
Ketonic decarboxylation of propanoic acid over a manganese(II) oxide catalyst in a tube furnace affords 3-pentanone.  Of commercial interest are related ketonizations using cerium(IV) oxide and manganese dioxide on alumina as the catalysts. 5-Nonanone, which is potentially of interest as a diesel fuel, can be produced from valeric acid.  Stearone is prepared by heating magnesium stearate.
An example of intramolecular ketonization is the conversion of adipic acid to cyclopentanone with barium hydroxide.
The synthesis of 4-heptanone illustrates the production of the metal carboxylate in situ. Iron powder and butyric acid are converted to iron butyrate. Pyrolysis of that salt gives the ketone.