Exchange of Benzene and Toluene

In the previous work, exchange of toluene was very briefly examined on a chromia activated to 470° in nitrogen. About 10% of the exchange was into methyl. We have now examined this exchange in greater detail as reported in Section VII,H. 

The effect of activation temperature upon the rate of exchange of toluene differs markedly from that for hydrogenation of 1-hexene, as shown in Table XII. The rate constant for exchange is a maximum 

Rates of Exchange of Toluene and of Deuterogenation of 1-Hexene on Amorphous Chromiaa 

Run 247 of Table XI is anomalous in having a higher exchange into methyl. This is reflected in the large value of D3. The activation of the chromia used in this experiment was quite different from that of the others, as described in Section VII,J. Similar patterns with high exchange into methyl had been found in these laboratories by Dr. K. Hirasa (run 10 of Table XI). In these experiments, activation involved a much slower rate of heating, 10° per hour. The values for k x in these 

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