5% Pt/-Al2O3 catalyzes the hydrothermal HDN of pyridine to
produce hydrocarbons. The catalyst can be reused up to at least
three times with only modest loss in HDN activity. The main products
of pyridine HDN in SCW are n-butane and n-pentane. The
proportion of n-pentane among the HDN products decreased as
the water density increased. In the absence of water, n-pentane
was the major HDN product, whereas in the presence of SCW, nbutane
was more abundant. Thus it seems clear that the presence of
water influences the HDN pathways. Hydrogen plays an important
role in pyridine HDN in SCW, but only a modestly superstoichiometric
H2/pyridine ratio (6.5:1) is required for essentially complete
nitrogen removal from pyridine. Performing the HDN reaction at
400 ◦C, 1.0 h, 0.025 g/cm3 water density, 5.5 MPa H2 and 100% catalyst
loading led to complete conversion of pyridine to hydrocarbon
products. Thus, this work shows that nitrogen in pyridine can be
effectively removed in SCW in the presence of a Pt/-Al2O3 catalyst
and high-pressure H2.