The reactions between hydroxymethylated 2-methoxy-4, 6-diamino-S-triazines (MMT) and urea in acidic aqueous solutions have been studied at 25° and 30°C in order to establish the range in which the pseudo-first order equation [1] is applicable, the velocity constant, and the activation energy. The concentration of the methylol group in the 0.00251 N hydrochloric acid medium was 0.0533 mol/l, and that of urea, 1.5. mol/l.The results are summarized as follows ;(1) When the averaged number of formaldehyde bound per mole of the triazine was 1 or more, the equation was applicable until ca. 18% of the total methylol groups had been reacted. This, however, varied to a considerable extent and in Sample A, this value was found to be ca. 80%.(2) MMT samples containing the same number of averaged bound formaldehyde do not necessarily give comparable velocity constants. This was probably due to the variance in the distribution of the mono-, di-, tri-, and tetra-hydroxymethylated components.(3) The activation energy values for Samples A and B were calculated to be 32.3 Kcal/mol and 32.9 Kcal/mol, respectively, which presumably represent the value for the mono-hydroxymethylated triazine.(4) Since the activation energy values of Samples C, D, E, F, and G fell in the range of 20.1-20.7 Kcal/mol, the values for the di-, tri-, and tetra-hydroxymethylated triazines would also be within that narrow range.
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