The octanol/water partition coefficient, logKow, for DNAN and
its reduced products followed the order: DNAN > 2-ANAN > 4-
ANAN > DAAN (Table 2), which is the exact opposite of the
observed solubility trend. Successive replacement of the ANO2
groups by ANH2 groups in DNAN therefore reduces the hydrophobicity
(Table 2). The precursor, DNAN, which is less soluble than
any of its amine derivatives, exhibited a higher logKow value
(1.58). The fully reduced DAAN, which partially ionizes in water,
is very polar and has a marked preference for water over organic
solvents (logKow < 1). TNT, with its three ANO2 groups, was the
most hydrophobic chemical of all (1.8 < logKow < 2.0).
With significantly higher solubility in water and equal or lower
hydrophobicity than DNAN, DNAN products including 2-ANAN, 4-
ANAN, and DAAN have a high potential to migrate through subsurface
soil unless their migration is slowed down by immobilization
mechanisms different from simple hydrophobic partitioning. The
next section is aimed at elucidating soil–water interactions for
DNAN and its products.