EFFECT OF THE NUMBER OF METHYLENE GROUPS PER MOLECULE ON THE REACTIVITY OF BOTH AMINO AND CARBOXYL GROUPS IN HYDROGEN-ISOTOPE EXCHANGE-REACTION

In order to reveal to what extent the number of methylene groups per m olecule can have an effect on the reactivity of a material having two different kinds of functional groups, the hydrogen-isotope exchange re action (T-for-H exchange reaction) between HTO vapor and one of alipha tic compounds having both COOH and NH, groups has been observed in the gas-solid system at a range of 50 similar to 80 degrees C. The rate c onstants for both COOH and NH2 groups in each material were obtained b y applying the A ''-McKay plot method to the data observed. Comparing the rate constants has lead to the following three conclusions. (1) Th e reactivity of the two groups increases with a rise in temperature. ( 2) The greater the number of methylene groups is, the smaller the reac tivity is of the material (i.e., the smaller the reactivity is of both the COOH and NH2 groups in the material). (3) The reactivity of certa in aliphatic materials having two different kinds of functional groups can only be analyzed with the A ''-McKay plot method as well as certa in aromatic materials having two different kinds of functional groups.