Complexing of sulfur(IV) oxide with hexamethylenetetramine and hexamethylenediamine in aqueous solutions

Complex formation of sulfur(IV) oxide with ethylenediamine and its derivatives in water

“…Parameters of curves of conductometry titration (Fig. 4b) of 0.1 mol/L solutions of ethylenediamine and its derivatives with gaseous SO 2 at 293 K solutions of ethylenediamine and its derivatives with gaseous SO 2 corresponded to kinks in the conductometric titration curves Δκ = f[Q(SO 2 )], coinciding with the data in [6,8]. Combined analysis of potentiometry, redoxometry and conductometry data has given the consistent information on the composition of onium salts formed in the SO 2 -organic base-water systems.…”

“…Procedures of potentiometric and chronoconductometric titrations have been described elsewhere [6,21]. Potentiometric measurements were performed using a рН-121 pH-meter.…”

“…Earlier studies of the Am-H 2 O systems (Am for aminoethanol and its derivatives, hexamethylenediamine, or hexamethylenetetramine) [1][2][3][4][5][6][7][8][9] have demonstrated that chemosorption of sulfur(IV) oxide with aqueous solutions of N,О-containing organic bases results in onium sulfites, hydrosulfitesand pyrosulfites of protonated forms of the mentioned amines as the major interaction products detected by electrochemical methods (potentiometry, redoxometry, and conductometry) [2][3][4][5][6]8] as well as isolated in the pure form [7,9]. Relative stability of the products has been estimated [2,3,6,8].…”

“…3). Hence, the amines behavior was similar to that of animoethanol, hexamethylenetetramine, and hexamethylenediamine [2][3][4]6].…”

“…Hence, the interaction between ethylenediamine and sulfur dioxide in the aqueous solutions resulted in a complete binding of the first amino group into the onium hydrosulfites and pyrosulfites (similarly to the cases of aminoethanol and its derivatives [2,4]), whereas the second amino group was partially converted into the onium sulfite.…”