Zn/Al/Ce mixed oxides derived from hydrotalcite-like precursors were employed as effective and recoverable heterogeneous catalyst for MPC synthesis via DMC aminolysis.
Dimethyl carbonate
aminolysis is an effective and green pathway
for the synthesis of methyl
N
-phenyl carbamate (MPC),
which is an important intermediate for the synthesis of polyurethanes
and many other chemicals. In this work, we demonstrate the fabrication
of Zn/Al/Pb mixed oxides as efficient and stable heterogeneous catalysts
for MPC synthesis. The catalysts are prepared via facile coprecipitation
and subsequent thermal annealing. Their micromorphology and physical–chemical
properties are characterized by X-ray diffraction (XRD), scanning
electron microscopy (SEM), transmission electron microscopy (TEM),
scanning TEM (STEM), X-ray photoelectron spectroscopy (XPS), and NH
3
-TPD. The results show that rather than being doped into ZnO
and/or Al
2
O
3
, PbO is highly dispersed in the
ZnO/Al
2
O
3
base forming ultrafine nanoparticles.
Despite the weak interactions within the mixed oxides, the high density
of active sites generates outstanding catalytic activity and cycling
stability for MPC synthesis, with an aniline conversion of almost
100% and MPC yield of up to 90% during six repeated tests, providing
great potential for their further application.
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