Method for preparing ketones by pyrogenic reaction of aldehydes, alcohols, acids or esters

A process for preparing ketones of formula I

• in which:
• A and B, which are identical or different, are selected from the group consisting of an optionally substituted saturated aliphatic hydrocarbon group;
• an optionally substituted aromatic hydrocarbon group;
• and an optionally substituted saturated carbocyclic group;
• said process comprising reacting, at a temperature between 250 and 500° C., a compound of formula II:
• A—X II
• with a compound of formula III:
• B—Y III
• in which:
• A and B are as defined above;
• and X and Y, which are identical or different, are selected from the group consisting of a hydroxyl function, a carboxyl function, a —COH function and an ester function,
• in a heat carrier solvent having a boiling point of more than 250° C., in the presence of a catalyst comprising at least one chemical compound of an element selected from alkali metals, alkaline earth metals, lanthanides, Si, Al, Zn, Cu, Ni, Co, Fe, Mo, Mn, Cr, V, Ti, Zr, U, Rh, Tl, Ag, Cd, Pb, Y, Sc and Th, in which the element is in the divalent state or has a higher valence,
• wherein the heat carrier solvent comprises a solvent having a boiling point of more than 250° C. which is selected from the group consisting of saturated or unsaturated aliphatic carboxylic acids;
• metal salts of said carboxylic acids;
• symmetric ketones derived from said carboxylic acids, of formula R°—CO—R° in which R° is such that R°—COOH represents a saturated or unsaturated aliphatic carboxylic acid;
• and mixtures thereof.