Thermochemical characteristics of nicotinamide protolytic equilibria in water-dimethylsulfoxide mixtures

• DOI: 10.1134/s0036024412040115
• Publication Date: 2012-02-25T23:29:49Z
• Authors: K. V. Grazhdan; G. A. Gamov; S. V. Dushina; V. A. Sharnin
• Keywords: 02 engineering and technology; 0210 nano-technology

The heat effects of nicotinamide protonation in water-dimethylsulfoxide (DMSO) solutions over the concentration range 0–0.75 DMSO mole fractions were determined calorimetrically at 25.00 ± 0.01°C and ionic strength 0.25 (NaClO4). Changes in the enthalpy of protonation as the content of DMSO increased were found to be described by an S-shaped curve. This curve shape was caused by the dynamics of reagent solvation contributions as the concentration of DMSO grew with the predominance of the nicotinamide solvation contribution.