Development of a mechanistic kinetic model of the higher alcohol synthesis over a Cs-doped Zn/Cr/O catalyst. 2: Analysis of chemical enrichment experiments

A previously developed kinetic model of higher alcohol synthesis over Cs-doped Zn/Cr/O catalysts is tested against chemical enrichment experiments. By simulating the addition of selected reaction intermediates to the CO/H2 feed stream and comparing predicted and measured effects on the product distribution, novel pieces of evidence are gained concerning the mechanistic consistency of the model. The adequacy of the kinetic scheme is confirmed. However, inaccuracies due to the lack of previous information and to the numerical complexity of the model have been identified. In particular, an overestimation of the contribution of ketones in the chain-growth process of aldehydes and primary alcohols has been detected. Such inaccuracies were well disguised by the satisfactory fit of the model to standard kinetic data and by the chemical consistency of the parameter estimates and could be put into light only by the present perturbative analysis of the model.