The invention relates to a process for the production of 5-formylvaleric acid and adipic acid or esters thereof from an isomeric mixture of pentenoic acid or esters thereof said mixture comprising at least 4-pentenoic acid or esters thereof, and further comprising 3-pentenoic acid and/or 2-pentenoic acid or esters thereof.The process allows for efficient production of two different intermediates for producing polyamide using a single process, with good selectivity, little waste, in an economically efficient fashion. The process is very suitable to use an isomeric pentenoic acid mixture obtained from valerolactone, and can be used to produce renewable polyamide intermediates using a single process.