In this paper, the authors deal with the dissolution of acid anhydride in water followed by the hydrolysis reaction.
Classification may be made of the types of reaction taking place, depending upon the relative rates of diffusion and hydrolysis of the acid anhydride.
(1) Diffusion resistance is controlling and the over-all rate of reaction depends only on the rate of solution. In this case the higher the agitator speed, the larger the rate of solution.
(2) Diffusion resistance and the chemical resistance to hydrolysis are comparable in magnitude. In this case the over-all rate of reaction depends not only on the agitator speed, but also on the rate of hydrolysis.
(3) Chemical resistance to hydrolysis is controlling and the over-all rate of reaction is independent of the agitator speed.
The authors derived the generalized rate equation and demonstrated the three types of reaction by the hydrolysis reaction of phthalic acid anhydride and benzoic acid anhydride suspended in water under agitation.
The authors propose the idea of the "degree of transitional saturation" and the "agitation coefficient for heterogeneous reaction"
The latter is useful for the determination of the available agitation intensity for heterogeneous liquid phase reactions.

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In liquid-liquid systems, the effects of agitation for promoting mass transfer are set forth as follows:
(1) Increase in the interfacial area.
(2) Diminution of diffusional resistance in continuous phase.
(3) Improvement in the mixing of the inner part of droplets.
The authors measured the interfacial area and the over-all reaction rate for various liquid-liquid systems in agitation, and obtained the following conclusions.
(1) For a liquid-liquid system whose density difference is zero and where simple physical dissolution of dispersed phase or diffusion-controlling reaction takes place, the increase in the rate of mass transfer is proportional to the increase in the interfacial area caused by the increase in agitator speed. Therefore the mass transfer resistance in the outer-side diffusional film of droplets is constant regardless of the agitator speed.
(2) For a system where density difference is zero and where diffusion-controlling reaction takes place, the increase in agitator speed is slightly effectivc for the diminution of the outer-side diffusional resistance of droplets. However, as the density difference in liquid-liquid system is very small, the purpose of agitation is chiefly to increase the inter-facial area and to diminish, only slightly, the diffusional resistance.
(3) For the system where density difference is zero and the diffusional and reaction resistance are comparable in magnitude, the over-all rate of reaction is, in the range of lower agitator speed, proportional to the increase in the interfacial area caused by the intensification of agitation.
At a higher agitation speed, the concentration of dissolved and unreacted reactant in the continuous phase increases gradually with the increase in agitator speed, but the increase in the interfacial area is not accompanied by the increase in the over-all rate of reaction. Finally, the continuous phase is to be in saturated condition and the over-all reaction rate is to be controlling, if the overall rate is to be independent of agitator speed. Thus in liquid-liquid reaction system, there is sometimes an upper limit to effective agitator speed.

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In the previous paper³⁾ the authors discussed the agitation effect on the mixing of the outer side diffusional film of liquid droplets in liquid-liquid systems. In this paper the authors try to clarify the agitation effect on the mixing of the inner part of dispersed droplets.
The interfacial area and mass transfer rate were measured simultaneosly of the systems which were
(a) H₂O-(iso-valeryl chloride)-(α-nitropropane),
(b) H₂O-(iso-valeryl chloride)-tetraline,
(c) H₂O-(iso-valeryl chloride)-(CCl₄+paraffine oil).
Systems followed by diffusion-controlling chemical reaction.
Conclusions:
(1) In the range of low agitator speed, the state of mixing of the inner part of dispersed droplets is nearly equal to that of perfect mixing.
(2) When the agitator speed is increased, the mixing rate of the inner part of droplets is somewhat decreased, as the result, i.e., the increase in mass transfer rate is not proportional to the increase in the interfacial area in a system of Δ_ρ=0
(3) When the agitator speed is increased and the diameter of droplets is decreased, the values of the mass transfer rate, estimated on the assumption that the mass transfer is caused by molecular diffusion only, are nearly equal to the estimated values of the mass transfer rate in perfect mixing. Therefore in the range of high agitator speed, the effect of agitation on the mixing of the inner part of droplets is slight in extent.
(4) Even when high viscosity liquid is used for the solvent of dispersed phase, in the range of low agitator speed, the inner part of droplets represents a state of almost perfect mixing.
(5) Generally speaking, in liquid-liquid extraction systems the difference in density between phases is not large, so that the increase in agitator speed has its effect principally on the increase in interfacial area.

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This work was undertaken to study the ion exchange equilibrium of uranyl sulfate ion and sulfate ion by highly basic anion exchangers. The ion exchange equilibrium and the capacity of exchangers were measured by the batch and the column method, respectively. Exchangers used in this experiment were Amberlite IRA 400 and Duolite A 101.
The results obtained are as follows:
1) The equilibrium curves can be given by Eq. (1), in which the characteristic value of equilibrium, K, is the determing factor for said curves.
2) The value of K varies with pH value as well as the concentration of SO₄^-- and UO₂SO₄, but is scarcely influenced by the temperature.
3) Uranyl sulfate complex ions are supposed to be in the form of UO₂(SO₄)₃^4- at pH values below 3.0, and in the form of UO₂(SO₄)₂^2- at pH values above 3.0.
4) The following is found to be an optimum operational condition for the sulfuric acid leaching solution in the ion exchange column:
pH=3.0-4.5, SO₄^-- concentration (as SO₄/UO₂ mol ratio)=1-15, and UO₂SO₄ concentration=2.0-4.0g/l

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The most economical (optimum) conditions for a pneumatic conveyor (a suction and a pressure type) employed for the purpose of the solid-powder transportation were calculated against the solid-air mass flow rates (mixture ratios), under some adequate assumptions, by two approximation methods. One of them depends upon an approximate driving horse-power and the other on the total cost of a pneumatic system in a year, viz., the sum of the consumed horse-power cost, X, the pipe line cost, Y, and the blower (driving equipment) cost, Z.
Basic equations are Eqs. (1)-(4). Eqs. (6)-(8) and Figs. 2-5 are obtained by the former of the appromination methods, and Eqs. (10)-(16) and Figs. 7-10 by the latter of them. They show that the theoretical optimum conditions are found in a comparatively lower mixture ratio than we used to consider it to be, -about 1 to 10 in ordinary systems for practical use.

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