Process for the synthesis of 2-hydroxy-4-alkyloxy benzophenone

A process for the preparation of 2-hydroxy-4-alkyloxybenzophenones having formula (I) ##STR4## wherein R' represents a hydrogen atom, an alkyl radical with from 1 to 20 carbon atoms, an arylalkyl radical with from 7 to 20 carbon atoms, and

• R represents an alkyl radical with from 1 to 16 carbon atoms, an arylalkyl radical with from 7 to 20 carbon atoms, a cycloalkyl radical with from 5 to 10 carbon atoms or an alpha beta unsaturated alkene radical which contains from 3 to 6 carbon atoms;
• by the selective alkylation of a 2,4-dihydroxy-benzophenone having formula (II) ##STR5## wherein R' has the same meaning defined above,
• with a dialkyl carbonate, in a liquid phase, at a temperature of between 120.degree. and 220.degree. C. and at a total pressure ranging from 2 to 60 ate, in the presence of a catalyst selected from the group consisting of compounds of alkaline metals of a basic nature, halides of alkaline metals, and alkyl halides,
• with the proviso that when the catalyst is a compound of an alkaline metal of a basic nature, the alkylation reaction is carried out at a partial pressure of the carbon dioxide which is developed under the reaction conditions of not less than 2 ate.