Abstract
2-Aminoethylisothiuronium (AET) and 3-aminopropylisothiuronium (APT) salts undergo, in the presence of alkali, the rapid transguanylation accompanying with the continuous pH drop. Since the liberation of hydrogen ion was resulted undoubtedly from the transguanylation, the calculation of the extent of this transformation was attempted from the pH drop. The extent of the transguanylation, abbreviated as T, was expressed briefly as follows. p (1-T)=ΔpH This equation can be used in the case of APT, which undergoes the transguanylation alone. AET is cyclized along with the transguanylation, and the cyclization product, 2-aminothiazoline, is able to associate with free hydrogen ion. Therefore, the pH drop observed as a result of a certain extent of the transguanylation is decreased according to the increasing extents of the cyclization. The calculation in the case of AET was performed by using the following equation ; T=1-(1-a) K/a [H+]+(K-K")C/(K"+[H+])a where C, a, K and K"represent the extent of the cyclization determined experimentally, the equivalent of alkali added, the ionization constants of the transguanylation and the cyclization products, respectively.
