Process for producing an aryl-imido-peralkanoic acid by oxidizing the corresponding aryl-imido-alkanoic acid with hydrogen peroxide

A process for continuously producing an arylimidoperalkanoic acid having the following formula:

• ##STR4##
• wherein A is selected from the group consisting of benzene, 1,2-naphthalene or 2,3-napthalene rings, ##STR5##
• in which n is an integer ranging from 3 to 7;
• the benzene or naphthalene rings are either unsubstituted, or substituted by one or more carboxy groups;
• and R.sub.1 and R.sub.2, which are the same, or different from each other, are selected from the group consisting of H and C.sub.1 -C.sub.5 alkyl groups bearing carboxy, percarboxy, hydroxy (OH), nitro (NO.sub.2) and C.sub.1 -C.sub.5 alkoxy substituents, said process comprising the following steps:
• (a) Preparing a solution of an arylimidoalkanoic acid having the following formula:
• ##STR6## wherein A, n, R.sub.1 and R.sub.2 are the same as above, and wherein the benzene or napthalene rings are either unsubstituted, or substituted by one or more carboxy groups, in a halogenated solvent selected from the group consisting of methylene chloride (CH.sub.2 Cl.sub.2) and trichloromethane (CHCl.sub.3), said solution being prepared by dissolving an amount of said arylimidoalkanoic acid which is:
• (i) equal to, or less than the solubility threshold of said arylimidoalkanoic acid in said halogenated solvent at the reaction temperature as defined in step (b) below, and
• (ii) greater than the amount of said arylimidoalkanoic acid which stoichiometrically corresponds to the solubility threshold of said arylimidoperalkanoic acid in said halogenated solvent at the reaction temperature as defined in step (b) below:
• (b) continuously reacting the solution prepared in step (a) at a reaction temperature of 10.degree.-35.degree. C., with aqueous H.sub.2 O.sub.2, in the presence of a string acid selected from the group consisting of H.sub.2 SO.sub.4, oleum, methanesulfonic acid, trifluoromethanesulfonic acid, fluorosulfonic acid, and mixtures thereof, said strong acid having a molar feed ratio to said arylimidoalkanoic acid of less than 2, to form a reaction product having an aqueous phase and an organic phase;
• (c) separating the aqueous phase and the organic phase;
• (d) recovering the arylimidoperalkanoic acid from the organic phase;
• and
• (e) recovering the halogenated solvent from the organic phase and recycling said recovered halogenated solvent for use in step (a).