Abstract: This invention relates in part to processes for producing one or more substituted or unsubstituted aldehyde acids or salts, e.g., 5-formylvaleric acid or salt, which comprises subjecting one or more substituted or unsubstituted alkadienes, e.g., butadiene, to hydroxycarbonylation in the presence of a hydroxycarbonylation catalyst, e.g., a metal-organophosphorus ligand complex catalyst, and optionally neutralization with a base to produce one or more substituted or unsubstituted unsaturated acids or salts, e.g., pentenoic acid or salt, and subjecting said one or more substituted or unsubstituted unsaturated acids or salts to hydroformylation in the presence of a hydroformylation catalyst, e.g., a metal-organophosphorus ligand complex catalyst, to produce said one or more substituted or unsubstituted aldehyde acids or salts and/or one or more substituted or unsubstituted epsilon caprolactam precursors.