The most representative impurities in is an element of-caprolactam produced from cyclohexanol obtained by partial hydrogenation of benzene are the delta-valerolactams. These impurities come from the dehydrogenation-oximation-Beckmann rearrangement of the methylcyclopentanols that are typical impurities in the cyclohexanol obtained from benzene. The dehydrogenation of cyclohexanol is carried out in a fixed-bed reactor with a commercial catalyst based on copper oxide. The evolution of these 1-, 2-, and 3-methylcyclopentanol impurities during dehydrogenation is analyzed separately and in a combined way, and the products are identified and quantified. The cyclohexanone obtained after cyclohexanol dehydrogenation and reaction mixture rectification is taken as a reactant for the oximation and Beckmann rearrangement stages. The evolution of the 1-methylcyclopentanol and 2- and 3-methylcyclopentdnones impurities contained on this purified cyclohexanone to the final impurities found in c-caprolactam are analyzed.