The Influence of Phosphate Buffer on the Formation of N-Nitrosodimethylamine from Dimethylamine Nitrosation

Table 2

Calculated activation energies and reaction energies (in kcal/mol) for possible reactions involved in the phosphate-buffered “DMA + NO₂⁻” reaction system at the B3LYP/6-311+G(d,p) level.

Reactions	Δ𝐻^≠	Δ𝐺^≠	Δ𝐻	Δ𝐺
DMA + N2O3 → NDMA + HNO2	6.87	8.24	−15.90	−18.05
N2O3 + H2PO4^− → HPO4NO^−+ HNO2	8.40	10.83	−2.59	−2.37
DMA + HPO4NO^− → NDMA + H2PO4^−	22.05	24.97	−28.39	−28.52
N2O3 + H2O → 2HNO2	12.80	15.85	1.50	−0.06
HPO4NO^− + H2O → H2PO4^− + HNO2	25.41	28.63	−8.77	−8.15