酸性水溶液中におけるメチロール化2-メトキシ-S-トリアジンと尿素との反応(その1)

抄録

Alkaline condensation of 2-methoxy-4, 6-diamino-S-triazine (MAT) with for-maldehyde (F) gives hydroxymethylated products (MMT) usually as a mixture of mono-, di-, tri-, and tetra-methylol derivatives. If the reaction velocities between each of the hydroxymethyl groups in MMT and the amino group of urea are equal, the mixture MMT would behave as a single compound containing the averaged ‘n’ moles of F. In order to confirm this assumption, the reaction velocities between MMT and urea in an acidic aqueous solution containing 1.25×10^-3-3-2.08×10^-2 N hydrochloric acid have been measured at 25, 30, 35, and 40°C by iodometric method. The concentration of MMT (n=2.13) in the solution was 0.025 mol/l, and that of urea, 1.5 mol/l. The following results were obtained:(1) The above assumption holds true until 20% of the total methylol groups have been reacted.(2) The velocity constant was approximately proportional to the acid concentration over the range 1.25×10-3-5.02×10-3 N at a given temperature.(3) The velocity constants at 25, 30, 35, and 40°C were in good agreement with the Arrhenius′ equation, and the activation energy was calculated to be 20.7 kcal/mol.