NOVELTY - Reducing (P1) emission of volatile organic compounds from ketonization process, comprises: (a) heating vaporized feed stream (9) comprising at least one carboxylic acid in direct-fired furnace (3) comprising combustion zone to produce superheated feed stream (15); (b) contacting superheated feed stream with metal oxide catalyst (I) to form gaseous product mixture comprising at least one ketone, carbon dioxide and at least one volatile organic compound byproduct; (c) separating ketones; and (d) feeding e.g. at least a portion of volatile organic compound byproducts to combustion zone.    USE - The processes are useful for reducing an emission of volatile organic compounds from a ketonization process and preparing acetone (all claimed).    ADVANTAGE - The process: reduces coking within the ketonization reactor; requires no additional costly unit operations for destruction of the volatile organic compounds, hence it is efficient and cost effective; does not require an additional step for recovery of the solvent from the byproduct carbon dioxide stream after absorptive recovery of the acetone; and facilitates greater than or equal to 99% recovery of acetone.    DETAILED DESCRIPTION - Process (P1) for reducing an emission of volatile organic compounds from a ketonization process, comprises: (a) heating a vaporized feed stream (9) comprising at least one carboxylic acid in a direct-fired furnace (3) comprising a combustion zone to produce a superheated feed stream (15); (b) contacting the superheated feed stream with a metal oxide catalyst (I) to form a gaseous product mixture comprising at least one ketone, carbon dioxide and at least one volatile organic compound byproduct; (c) separating the ketones from the carbon dioxide and volatile organic compound byproducts; and (d) feeding at least a portion of the carbon dioxide and the volatile organic compound byproducts to the combustion zone of the direct-fired furnace. INDEPENDENT CLAIMS are also included for:    (1) a process (P2) for reducing the emission of volatile organic compounds from the production of acetone, comprising: (a1) heating the vaporized feed stream comprising acetic acid in the direct-fired furnace to produce the superheated feed stream having a temperature of 350-550 degrees C; (b1) contacting the superheated feed stream with the catalyst (I) to produce a gaseous product mixture comprising carbon dioxide, acetone and the volatile organic compound byproducts; (c1) contacting the gaseous product mixture with an absorption solvent to produce a crude liquid absorbent stream comprising a major portion of the acetone in the gaseous product mixture and a gaseous byproduct stream comprising carbon dioxide, a minor portion of the acetone in the gaseous product mixture, and the volatile organic compound byproducts; and (d1) feeding at least a portion of the gaseous byproduct stream to the combustion zone of the direct-fired furnace, where the combustion zone contains sufficient oxygen for complete combustion of the acetone and the volatile organic compound byproducts present in the gaseous byproduct stream fed to the combustion zone; and    (2) a process (P3) for preparing acetone, comprising: the steps (a1) and (b1) as above per se; contacting the gaseous product mixture with water to produce a liquid absorbent stream comprising a major portion of the acetone in the gaseous product mixture and a gaseous byproduct stream comprising carbon dioxide, a minor portion of the acetone in the gaseous product mixture, and the volatile organic compound byproducts; the step (d1) as above per se; and distilling the liquid absorbent stream to produce a distillate comprising a refined acetone product and a distillation bottoms comprising water.    DESCRIPTION OF DRAWING(S) - The figure shows a schematic flow diagram of a ketonization process.    Vaporization unit (1)    Direct-fired furnace (3)    Conduit (7)    Vaporized feed stream (9)    Superheated feed stream (15)