Donees Contacted and Separated

Donors and Donees Contacted and Separated.—Teichner was the first to recognize the fundamental importance to the problem of spillover of experiments in which the donee is ultimately separated from the donor and the adsorptives, and examined separately for evidence of the presence of spillage. Hydrogen is, so far, the only adsorptive to have been investigated in this manner and its detection on the donee has been accomplished by way of the chemical reactions it induces. 

The short communication by Lau and Sermonwill first be dealt with as its content is the smaller and the less complicated. The donor was platinum (1.7 wt %) on y-alumina pellets retained in the base of a bed of particles of the 

Teichner and his group have used a direct method to detach the donee from the donor.They devised an apparatus in which the donor, in a bucket, is first immersed in a bed of particulate donee (to give good contact) and then drawn up by a windlass out of the bed, into a separate, isolatable reaction chamber. Thus the donor and donee can be given various treatments in a lower 

The effect of spillover onto the aluminas included unusual selectivities in the isomerization of methylcyclopropane and in the hydrogenation of butenes and benzene. 

There can be little doubt that some alteration of the donee has occurred, but its precise description is elusive. One must note that the test reaction times are all very long, thus increasing the possibilities of surface contamination. All authors agree that much work remains to be done. 

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