β Scribed by F. Contamine; F. Faid; A.M. Wilhelm; J. Berlan; H. Delmas
No coin nor oath required. For personal study only.
Liquid-solid mass transfer measurements under ultrasound are presented and compared to reaction conversions. These comparisons have been achieved with two emission conditions: a transducer located at the bottom of a cylindrical reactor, or a horn dipping into a vessel. Mass transfer coefficients were. proved to be very different throughout the reactor: axially they vary according to a standing wave, and radially the high values are concentrated above the transducer. The power input has an influence up to a plateau. These trends have also been found for a homogeneous reaction (the oxidation of potassium iodide) carried out in the whole reactor or locally in microreactors. A solid-liquid reaction (Michael addition) exhibited the same Dower dependence: measurement of particle diameter together with the reaction'yield proved ultrasound to prevent agglomeration of the solid. Nevenheless, acceleration is not only due to mass transfer effects, a chemical effect must exist; the latter effect was demonstrated by addition of a radical scavenger which reduced the reaction rate.
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## Abstract Review: 59 refs.
## Abstract The effect of the magnetic field on CIDNP can be found in many chemical reactions. It is considered to result from the fact that the probability of singletβtriplet transitions in a radical pair is determined by magnetic interactions in the pair and is field strength dependent. In the pr