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Hydrogenation of nitrobenzene and m-nltrotoluene in mixture was performed in a monolithic Pd catalyst reactor and with ground catalyst in a slurry reactor. The gas-liquid flow in the narrow channels of the monolithic catalyst was a segmented two-phase flow. The mass transfer of hydrogen directly from the gas plugs to the channel wall was found to be the dominating transport step. Tiis direct transport corresponded to more than 70% of the total transport of hydrogen to the channel wall In a typical run. The decreased selectivity of aniline formation found in the hydrogenations In the monolithic catalyst was explained by the influence of the film transport resistance near the channel wall. Hydrogenation of m-nltrotoluene was strongly delayed in the presence of nitrobenzene. Fitting different rate equations to the experimental data indicated that the reaction mechanism is complicated.A novel type of catalytic reactor for liquid-phase hydrogenations was recently presented by Hatziantoniou and Andersson (1984). The catalyst was a monolith of a type similar to the catalyst often used for cleaning exhaust gas from cars. The catalyst consisted of a great number of thin parallel porous plane plates, separated by interstitial corrugated plates, thus forming parallel channels in which gas and liquid flow cocurrently.Besides a very low pressure drop of the flow of the monolithic catalyst of this type (Satterfield and Ózel, 1977), the mass transfer to the channel wall from the liquid was found to be much greater for a segmented gas-liquid flow than for a continuous liquid flow (Hatziantoniou and Andersson, 1982). This effect was explained by an in-

The diffusivities of hydrogen and glyceryl trioleate in cottonseed oil were determined at different iodine values. The diffusivity of hydrogen was shown to be ca. 100 times as great as that of the glyceryl trioleate. The diffusivities were shown to be dependent upon the iodine values. This influence could be explained, at least in the case of the glyceryl trioleate diffusion, by the difference of the viscosity of the oil. A separate determination of the solubility of hydrogen in the oil was a necessary part of the diffusivity determination.

The influence of mass transfer steps in the kinetic study of rapeseed oil hydrogenation in a laboratory reactor was estimated. Hydrogenations were carried out at 140–200 C and at 0.3–10 atm hydrogen pressure in the presence of 0.087% of commercial nickel‐on‐kieselguhr catalyst, corresponding to 0.05% of nickel. Despite intense mixing conditions on the macroscale of the bulk oil, corresponding to a reaction rate independent of further increase of the stirrer rate, the concentration differences across the liquid film surrounding the bubbles and the catalyst particles could not be neglected. The pore transport of triglycerides and hydrogen molecules was found not to be a slow step in most hydrogenations.

The kinetics of rapeseed oil hydrogenation was studied at 140-220C and at 0.3-10atm hydrogen pressure in a laboratory reactor in the presence of 0.05% nickel catalyst. A mathematical model was fitted to the experimental data, and temperature and pressure dependence of the different reaction steps was discussed on the basis of the model. The adequacy of the model was tested by means of a residual analysis.A Guide for Authors is Located in JAOCS 52(January):56A(1975)