A process for the production of a C 4 to C 15 oxo-alcohol comprising a hydroformylation step, a hydrogenation step and a step for distilling the product alcohol from the hydrogenation product, selected from (a) hydroformylating in the hydroformylation step a C 3 to C 14 olefin and hydrogenating in the hydrogenation step the product of hydroformylation to form the C 4 to C 15 oxo-alcohol, and (b) hydroformylating in the hydroformylation step a C 2 to C 4 olefin to form a C 3 to C 5 aldehyde, aldolising the C 3 to C 5 aldehyde in at least one aldol step to a dimer, trimer or tetramer thereof which is a branched C 6 to C 15 aldehyde, and hydrogenating in the hydrogenation step the branched C 6 to C 15 aldehyde to a branched C 6 to C 15 alcohol, whereby the content of conjugated unsaturated carbonyl compounds in the C 4 to C 15 alcohol is reduced by at least one of the steps selected from (i) if the olefin feed to the hydroformylation step in (a) is a C 6 to C 14 olefin, treating the C 6 to C 14 olefin feed to hydroformylation in (a) to reduce its content of conjugated unsaturated carbonyl compounds to below 13.5 meq/kg, (ii) treating the product of the hydrogenation step in (a) or (b) to reduce its content of conjugated unsaturated carbonyl compounds to below 13.5 meq/kg, and (iii) treating the product alcohol from the distillation step of the process to reduce its content of conjugated unsaturated carbonyl compounds to below 1.78 meq/kg; wherein the content of the conjugated unsaturated carbonyl compound in the olefin and/or the alcohol is reduced by adsorption. (a) hydroformylating in the hydroformylation step a C 3 to C 14 olefin and hydrogenating in the hydrogenation step the product of hydroformylation to form the C 4 to C 15 oxo-alcohol, and (b) hydroformylating in the hydroformylation step a C 2 to C 4 olefin to form a C 3 to C 5 aldehyde, aldolising the C 3 to C 5 aldehyde in at least one aldol step to a dimer, trimer or tetramer thereof which is a branched C 6 to C 15 aldehyde, and hydrogenating in the hydrogenation step the branched C 6 to C 15 aldehyde to a branched C 6 to C 15 alcohol, whereby the content of conjugated unsaturated carbonyl compounds in the C 4 to C 15 alcohol is reduced by at least one of the steps selected from (i) if the olefin feed to the hydroformylation step in (a) is a C 6 to C 14 olefin, treating the C 6 to C 14 olefin feed to hydroformylation in (a) to reduce its content of conjugated unsaturated carbonyl compounds to below 13.5 meq/kg, (ii) treating the product of the hydrogenation step in (a) or (b) to reduce its content of conjugated unsaturated carbonyl compounds to below 13.5 meq/kg, and (iii) treating the product alcohol from the distillation step of the process to reduce its content of conjugated unsaturated carbonyl compounds to below 1.78 meq/kg; wherein the content of the conjugated unsaturated carbonyl compound in the olefin and/or the alcohol is reduced by adsorption. (i) if the olefin feed to the hydroformylation step in (a) is a C 6 to C 14 olefin, treating the C 6 to C 14 olefin feed to hydroformylation in (a) to reduce its content of conjugated unsaturated carbonyl compounds to below 13.5 meq/kg, (ii) treating the product of the hydrogenation step in (a) or (b) to reduce its content of conjugated unsaturated carbonyl compounds to below 13.5 meq/kg, and (iii) treating the product alcohol from the distillation step of the process to reduce its content of conjugated unsaturated carbonyl compounds to below 1.78 meq/kg; wherein the content of the conjugated unsaturated carbonyl compound in the olefin and/or the alcohol is reduced by adsorption.