ChemCatChem
10.1002/cctc.202000547
COMMUNICATION
Cu0 and Cu+ surface areas have been obtained by combining
In summary, the roles of Cu/SiO
in the condensed diester
2
the XPS and N
2
O-titration results. As illustrated in Figure 3a, the
hydrogenation was studied for the first time. The Cu/SiO
2
photoelectron peaks at about 952.2 eV and 932.4 eV can be
assigned to the binding energy of Cu 2p1/2 and Cu 2p3/2
respectively, and the absence of shoulder peak between 942 eV
catalyst exhibited significantly higher diol selectivity of 100% and
space-time yield of 0.81 h-1 at the conversion of 95%. On basis
of the mass transfer analysis and kinetic study, the condensed
2+
to 944 eV suggests that the Cu in all samples has been totally
2
DMA hydrogenation is first order with respect to H , but zero
0
+[13]
reduced to Cu or Cu . In addition, the peaks at 572.7 eV and
70.0 eV in Figure 3b can be assigned to the binding energy of
order to DMA. It indicates that the concentration of hydrogen in
the liquid phase is the key factor for the condensed DMA
hydrogenation. Furthermore, the rate-determining step of this
reaction system was demonstrated to be the activation of
hydrogen, which depends on the adsorption ability of Cu0
species on the catalyst. These results give crucial important
guidance to the development of highly efficient catalyst for the
hydrogenation of condensed diesters.
5
+
0
[14]
Cu and Cu , respectively . The Cu LMM spectra were
deconvoluted and the ratio of Cu /Cu were calculated. Finally,
Cu surface areas were calculated by combining the ratio of
2
Cu /Cu with the Cu surface areas (measured by N O-titration).
+
0
+
+
0
0
The results are shown in Table 1, in which the big difference in
both SCu0 and SCu+ should be attributed to the different copper-
[5]
silica interaction induced by the various preparation methods .
Experimental Section
The details of the synthesis, characterization and evaluation of the
catalyst are provided in the electronic supporting information.
Acknowledgements
We appreciate the National Natural Science Foundation of
China for the financial support (21878227, U1510203).
Figure 4. The correlation between catalytic performances and copper species.
0
0
+
STY-SCu (a); TOFCu -SCu (b).
Keywords: Hydrogenation • Diester • Condensed phase •
Copper • Kinetics.
Figure 4a presents an approximately linear correlation between
0
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3
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