T-for-H exchange reaction between HTO vapor and two functional groups in an aromatic compound in a gas-solid system

Abstract

The hydrogen-isotope exchange reaction (T-for-H exchange reaction) between HTO vapor and an aromatic compound having two different kinds of functional groups has been observed at several temperatures. The rate constant (k) for each functional group in the T-for-H exchange reaction was obtained by using both the A"-MCKAY plot method and the data observed. Comparing these k with each other has led to the following four conclusions in the T-for-H exchange reaction. (1) The reactivity of both the COOH and OH groups increases with a rise in temperature. (2) As to the degree of the effect of the COOH group on the reactivity of monosubstituted phenols, the degree in p-hydroxybenzoic acid is greater than that in m-hydroxybenzoic acid. (3) The HAMME1T rule is useful for estimating the reactivity of a certain aromatic compound. (4) The A"-MCKAY plot method is also useful not only investigating the reactivity of the compounds having one kind of functional group, but also doing the reactivity of the compounds having two different kinds of functional groups.

Effect of Temperature (and the Degree of Crosslinking) on the Reactivity of Anion-Exchange Resins by Applying the OT-for-OH Exchange Reaction

“…As for © mentioned above, it can be considered that the activity absorbed on the resin (i.e., HTO molecule absorbed on the resin) is smaller at a higher temperature. Previously [1,2], as for the T-forBrought to you by | New York University Bobst Library Technical Services Authenticated Download Date | 6/29/15 2:08 AM Η exchange reaction, the higher the temperature is, the greater the activity is of the material used, while that for the OT-for-OH exchange reaction, the reverse result is seen. This appears to be due to decrease a rate of dissociation of HTO, leading to a lower amount of OT~ with an increasing temperature.…”

“…2. From the figure, it is found that © the real activity of IRA-400 based on OT-for-OH exchange reaction decreases with increasing temperature within the range of 40 ~ 80° C, © the real activity of IR-120B based on T-for-H exchange reaction increases with increasing temperature within the range of 20 ~ 80° C. Examining the results mentioned above, the following three points can be considered: (a) the exchange capacity of each resin may vary with temperature; (b) the degree of the dissociation of HTO water may vary with temperature; (c) the ratio of the rate of the dissociation of Formula (2) with that of Formula (3) may vary with temperature. However, in general, the exchange capacities of ion exchange resins hardly decrease within the range of 20 ~ 80° C [8].…”

“…In addition to the reports of hydrogen-isotope exchange reaction (T-for-H exchange reaction) in a heterogeneous system [1,2], we have recently presented the results of the exchange reaction between atomic groups (OT-for-OH exchange reaction) in the equilibrium state [3,4]. From the reports, the following has been found: (1) the isotope exchange reaction between atomic groups (OT-for-OH exchange reaction) occurred between each alkali metal (abbreviated as Μ below) hydroxide (or anion-exchange resin) and tritiated water (abbreviated as HTO water below); (2) the exchange rate for the OT-for-OH exchange reaction is small when the electronegativity of the Μ ion in Μ hydroxide is large; (3) the reactivity of a strongly basic anion-exchange resin is larger than that of weakly basic one; (4) the exchange rate for OT-for-OH exchange reaction may be smaller than that for T-for-H exchange reaction.…”

“…Considering the above-mentioned, the following four aims were undertaken in this work: (1) to clarify the behavior of the T-labeled hydroxyl group, (2) to clarify the effect of temperature on the reactivity of the anion-exchange resins, (3) to clarify the effect of the degree of crosslinking on the reactivity of anionexchange resins, and (4) to estimate the ratio amount of OT" to that of T + (they are generated from the dissociation of HTO).…”

Effect of the Number of Methylene Groups per Molecule on the Reactivity of Both Amino and Carboxyl Groups in Hydrogen-Isotope Exchange Reaction

“…The reactivity of several materials [1] has been clarified using the rate constants (k) for the materials in the hydrogen-isotope exchange reaction. These k values were calculated using both the A"-McKay plot method [2,3] and the data obtained in the gas-solid [4,5] (or liquid-solid [6,7]) system.…”