The kinetics of the hydrogenation and
cis/
trans isomerization of methyl oleate on a Ni/
-Al
2O
3 catalyst was studied in the absence of mass-transport limitation, at 398 K ≤
T ≤ 443 K and
370 kPa≤PH2≤650 kPa. On the basis of the Horiuti–Polanyi mechanism, involving a
σ half-hydrogenated surface intermediate, a kinetic model was derived in the framework provided by the Langmuir–Hinshelwood–Hougen–Watson formalism, using the advanced concept of semi-competitive
adsorption. The classical LHHW rate equations for competitive and non-competitive
adsorption between the hydrogen and large organic species were matched as asymptotic cases. Statistical results clearly demonstrated the inadequacy of the model approaching non-competitive
adsorption to describe the experimental data, but the residual sum of squares between experimental data and model predictions was insufficient to discriminate between the kinetic models based on competitive and semi-competitive
adsorption. However, the model considering semi-competitive
adsorption gave additional indication that the adsorbed molecules of
cis- and
trans-methyl oleate could cover up to eleven surface
sites, which is in excellent agreement with a rough estimate from
primary molecular modeling. This feature seems to be the most fascinating result, since it is factual and unattainable from the classical LHHW approaches. Results and distinctive features characterizing this advanced approach are highlighted. Some insights to improve parameter estimation and
adsorption model discrimination are also pointed out.