Process for the preparation of 2-aryl propionic acids

A process for the preparation of 2-aryl propionic acid of the formula III:

• wherein R1 is selected from the group consisting of phenyl, naphthyl, substituted phenyl and substituted napthyl;
• R2, R3, R4 and R5 are independently selected from the group consisting of hydrogen, methyl and substituted methyl;
• comprising the steps of:
• carbonylating an aryl compound selected from an aryl alcohol, an aryl halide of formula I:
• wherein R1, R2, R3, R4 and R5 are as stated above;
• and X is selected from halogen and —OH group;
• or an aryl olefin of formula II:
• wherein R1, R2, R3 and R4 are as stated above;
• in the presence of a halide source, wherein the halide source comprises a halide salt selected from the group consisting of lithium chloride, sodium chloride, potassium chloride, lithium iodide, lithium bromide, sodium bromide, sodium iodide, potassium bromide;
• potassium iodide, tetrabutyl ammonium chloride, and tetrabutyl ammonium iodide and mixtures thereof, a protonic acid wherein the protonic acid comprises a hydrohalic acid selected from the group consisting of hydrochloric acid, hydrobromic acid, hydroiodic acid, para-toluene sulphonic acid, methane sulphonic acid, trifluoromethane sulphonic acid, formic acid, oxalic acid, acetic acid, trifluoroacetic acid and mixtures thereof, water and a catalyst system, wherein the catalyst system comprises a heterogeneous metal selected from the group consisting of palladium, platinum, rhodium, iridium, ruthenium, cobalt, nickel and mixtures thereof;
• a phoshpine ligand selected from the group consisting of triphenyl phosphine, tris(p-tolyl)phoshine, tricyclohexyl phosphine, tris(p-chloro phenyl)phosphine, tris(p-fluoro phenyl)phosphine, tris(p-methoxy phenyl)phosphine, tributyl phosphine, tris(isopropyl)phosphine, bisdiphenyl phosphino ethane, bisdiphenyl phosphino propane, bisdiphenyl phosphino butane and mixtures thereof;
• in an organic solvent wherein the organic solvent is selected from an aromatic hydrocarbon, wherein the aromatic hydrocarbon is selected from the group consisting of benzene, toluene, xylene and mixtures thereof;
• a ketone selected from methylethyl ketone and acetone, a cyclic ether selected from tetrahydrofuran and dioxan, nitrile and amide in carbon monoxide atmosphere, at a temperature in the range of 30 to 130° C., for a period in the range of 0.3 to 24 hours, at a pressure in the range of 50 to 1500 psig;
• cooling the reaction mixture to an ambient temperature;
• flushing the reaction vessel with an inert gas;
• separating the catalyst system;
• removing the solvent;
• and
• isolating the δ-aryl propionic acid of formula III.