Hydrocarbon compounds having at least one nitrile function are converted into compounds having at least one carboxylic function by hydrating the nitrile functions into amide functions by reaction with water in the presence of a strong inorganic acid, and then hydrolyzing the amide functions into carboxylic functions by reaction with water and a strong inorganic acid; the carboxylic compounds thus obtained can be esterified into diesters, advantageously diester solvents.