ACID-BASE PROPERTIES OF AMINOMETHANESULPHONIC ACID N-n-PROPYL, N-n-BUTYL AND N-n-HEPTYL DERIVATIVES

Abstract

Acid-base properties of aminomethanesulfonic acid N-n-propyl (n-PrAMSA), N-n-butyl (n-BuAMSA) and N-n-heptyl (n-HpAMSA) derivatives (YAMSA) in aqueous solutions at 293 – 313 K were investigated by pH measurements. The ion-molecular composition of the Y+NH2CH2SO2O- – YNHCH2SO2O- – H2O systems, dissociation concentration constants of the second dissociation step for n-PrAMSA, n-BuAMSA and n-HpAMSA (at the isoelectric point where the ionic strength is 4,94 ∙ 10–4 М) were calculated and temperature dependences of the ΔG, ΔH, and ΔS цуre determined at 293–313 K. It was shown the indicated YAMSA in aqueous solutions to exist at a ratio CNaOH/QYAMSA Textr. – exothermic. For the dissociation process of investigated acids, enthalpy-entropic compensation was noted with the «isothermodynamic temperature» 303 K.

Keywords

• амінометансульфокислоти
• буферні розчини
• термодинаміка іонізації
• ліпофільність