The kinetics of the catalytic hydrogenation of benzene on a commercial nickel catalyst (dp=2.65mm) was studied by a differential type of flow reactor.
The conversion of benzene is 5-8% for ordinary runs, and the maximum deviation of the catalyst temperature in the bed is less than 8°C.
Initial rates of reaction without cyclohexane and the rate for reactants containing some cyclohexane were measured at atmospheric pressure over the following range of conditions.
Temperature: 140, 160, 180, 200 and 220 [°C]
Partial pressure: p_H=0.4-0.9, p_B=0.1-0.6 p_O=0-0.5 [atm.]
Flow rate: 26-31 [gr/cm²hr.]
Twelve different mechanisms were presented, and checked by comparing experimental data of initial rates with the characteristic curve of the modified rate equation
As a result, the most plausible rate-controlling step was found to be in the surface reaction between one adsorbed benzene molecule and three adsorbed hydrogen molecules on the same type of active sites.
The final equation recommended for the vapor-phase hydrogenation of benzene on a nickel catalyst is as follows;

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This paper is to establish a quantitativecriterion for predicting the conditions under which the effects of free convection on mass transfer from a single sphere could be ignored. The situation chosen here deals with laminar boundary layer flow near the forward stagnation point, where the free convection effects predominate.
The assumed velocity profile given in Eq.(2-16) is the sum of two factors, the velocity profile for forced flow and that for free flow. The concentration profile assumed is given in Eq.(2-4).
Based on these profiles, Eq.(2-21) is derived for the rate of mass transfer in terms of Sh number as an analytical expression of Eq.(1-4). Numerical results of Sh/Sh0 given in Eq.(2-25) are shown in Fig. 3 for several Sc numbers.
For negative buoyancy effects, the above correlations are modified and Eq.(2-25') is obtained. Numerical results are also shown in Fig. 4. In this case the separation point, (Gr/Re2) separation, was predicted as shown in Fig.5.The applicability of conventional assumptions, i.e., i) the additivity of Sh number expressed in Eq.(3-1), and ii) the equivalence of Gr number to Re number such as in Eq.(3-3'), is here discussed.

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The interfacial area and the size distribution of the dispersed droplets in liquid-liquid agitation systems are directly measured by photographs with a series of geometrically similar Rushton type standard turbine agitators.
Physical properties of the liquids are varied as widely as possible. The effects of the various factors on, interfacial area are investigated and the observed data are correlated by a dimensionless equation.
As the interfacial tension decreases, the interfacial area itself increases, while the effect of increases in. agitator speed decreases with the breaking up of the dispersed phase. This is due to the facts that a limitation in drop size appears during ordinary agitation performance and that the size distribution curves transform from Normal to Log-normal ones as the agitator speed increases. So in a system of low interfacial tension the diameter of the greater part of the droplets approaches the minimum limit.
The authors introduced a factor which shows the amount of decrease in interfacial area caused by the effect of limitation of the droplet size on the increase in agitator speed. The use of baffle plates for heavy liquid dispersion increases the interfacial area by several times and the baffles become more effective as the difference in densities between the dispersed and the continuous phase increases.

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Liquid-liquid extractions of acetic acid from acetic acid-methyl isobutyl ketone solution by means of water were studied in a pulsed perforated-plate column. Holdup of dispersed ketone phase and transfer rate of acetic acid, from which (HTU) _oe was calculated, were measured, and the performance characteristics of pulsed perforated-plate column based on the variation of holdup with the pulsed velocity was studied.
Three operation regions are defined from plots of holdup versus pulsed velocity of various conditions. Holdupcurves are divided into three parts; the mixer-settler region where holdup decreases with increasing pulsed velocity; transition region where holdup increases slowly; emulsion region where holdup increases abrubtly.
(HTU) _oe decreases with increasing pulsed velocity in the mixer-settler and transition regions, and increases in the emulsion region. Therefore, the minimum value of (HTU) _oe is obtained at the boundary point between the transition and emulsion regions.
The a_mf value at the two boundary points, holdup in the three operation regions and (HTU) _oe in the two operation regions were correlated as experimental equations.

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[in Japanese]

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