Temperature-Residence Time Mapping

The rate of Br/Li exchange reaction, as well as that of the decomposition of the aryllithium, is dependent on temperature. The temperature-residence time map is thus useful in analyzing the reactions and optimizing the reaction conditions. In addition to the temperature-residence time map for an ethyl ester, those for other esters are also prepared (Fig. 4.8). 

Fig. 4.8 Temperature-residence time map for Br-Ii exchange of afkyl o-bromobenzoate followed by protonation, a t-butyl o-bromobenzoate, b isopopyl o-bromobenzoate, c ethyl o-bromobenzoate, and d methyl o-bromobenzoate...

Fig. 4.14 Temperature-residence time map for I-Li exchange of alkyl p-iodobenzoates followed by protonation, a tert-butyl p-iodobenzoate, b Isopropyl p-iodobenzoate, c ethyl p-iodobenzoate, and d methyl p-iodobenzoate...

Making a temperature-residence time map for such reactions is useful for controlling the reactions at optimum temperatures and with optimum residence times enabling selective synthesis of desired products with high yields. 

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