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- Title
The effect of catalyst preparation on the activity of MoO-SiO catalyst in transesterification of diethyl oxalate.
- Authors
Bian, L.; Wang, S.; Ma, X.
- Abstract
Transesterification of diethyl oxalate (DEO) with phenol over MoO-SiO catalysts prepared by the sol-gel technique (MoO-SiO (SG)) and the impregnation method (MoO-SiO (I)) was conducted to produce diphenyl oxalate (DPO), which can be used as a precursor for manufacturing diphenyl carbonate (DPC). The sample MoO-SiO (SG) containing 12 wt % of MoO showed the best performance with 71.0% conversion of DEO and 32.0% selectivity to DPO. Compared to MoO-SiO (I), improvements in the DEO conversion and DPO selectivity with MoO-SiO (SG) were 16.1 and 7%, respectively. Crystal structure and phase composition of MoO-SiO (I) and MoO-SiO (SG) catalysts with varying MoO contents were investigated. The sample MoO-SiO (SG) with a similar chemical composition to MoO-SiO (I) has a larger specific surface area, indicating that the active component is well dispersed on the surface of the MoO-SiO (SG) catalysts. Results of XRD and XPS measurements suggest a high degree of dispersion of MoO-SiO (SG) catalysts that can account for an increase in DEO conversion and DPO selectivity. Coordinately unsaturated MoO species play a significant role in the catalytic performance of MoO-SiO (SG) catalysts in transesterification of DEO with phenol. In addition, IR measurements of pyridine adsorption and NH-TPD data indicate that the amount of acid sites on the surface of MoO-SiO (SG) exceeds that found for the surface of MoO-SiO (I). An enhanced concentration of surface MoO species in tetrahedral coordination coupled with the presence of weak Lewis acid sites appear to be the main reason why MoO-SiO (SG) catalysts are superior to the MoO-SiO (I) system.
- Subjects
MOLYBDENUM oxides; CATALYTIC activity; SILICON oxide; TRANSESTERIFICATION; OXALATES
- Publication
Kinetics & Catalysis, 2014, Vol 55, Issue 6, p763
- ISSN
0023-1584
- Publication type
Article
- DOI
10.1134/S0023158414060032