3155-16-6Relevant articles and documents
The effect of catalyst preparation on the activity of MoO3-SiO2 catalyst in transesterification of diethyl oxalate
Bian,Wang,Ma
, p. 763 - 769 (2014)
Transesterification of diethyl oxalate (DEO) with phenol over MoO3-SiO2 catalysts prepared by the sol-gel technique (MoO3-SiO2 (SG)) and the impregnation method (MoO3-SiO2 (I)) was conducted to produce diphenyl oxalate (DPO), which can be used as a precursor for manufacturing diphenyl carbonate (DPC). The sample MoO3-SiO2 (SG) containing 12 wt % of MoO3 showed the best performance with 71.0% conversion of DEO and 32.0% selectivity to DPO. Compared to MoO3-SiO2 (I), improvements in the DEO conversion and DPO selectivity with MoO3-SiO2 (SG) were 16.1 and 7%, respectively. Crystal structure and phase composition of MoO3-SiO2 (I) and MoO3-SiO2 (SG) catalysts with varying MoO3 contents were investigated. The sample MoO3-SiO2 (SG) with a similar chemical composition to MoO3-SiO2 (I) has a larger specific surface area, indicating that the active component is well dispersed on the surface of the MoO3-SiO2 (SG) catalysts. Results of XRD and XPS measurements suggest a high degree of dispersion of MoO3-SiO2 (SG) catalysts that can account for an increase in DEO conversion and DPO selectivity. Coordinately unsaturated MoO3 species play a significant role in the catalytic performance of MoO3-SiO2 (SG) catalysts in transesterification of DEO with phenol. In addition, IR measurements of pyridine adsorption and NH3-TPD data indicate that the amount of acid sites on the surface of MoO3-SiO2 (SG) exceeds that found for the surface of MoO3-SiO2 (I). An enhanced concentration of surface MoO3 species in tetrahedral coordination coupled with the presence of weak Lewis acid sites appear to be the main reason why MoO3-SiO2 (SG) catalysts are superior to the MoO3-SiO2 (I) system.
MANUFACTURING METHOD OF DIPHENYL OXALATE, MANUFACTURING METHOD OF DIPHENYL CARBONATE AND MANUFACTURING METHOD OF POLYCARBONATE
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Paragraph 0052-0053, (2017/02/24)
PROBLEM TO BE SOLVED: To manufacture high purity diphenyl oxalate efficiently, stably and continuously. SOLUTION: There is provided a manufacturing method of diphenyl oxalate including reacting dialkyl oxalate and phenol in the presence of a catalyst and using a compound represented by the following general formula (1) as the catalyst. M(OAr)mRn (1), where M represents one metal of Al, Ti, V, Fe, Zn, Sn and Pb, Ar represents an aryl group having a substituent or an unsubstituted aryl group other than an unsubstituted phenyl group, R represents an alkyl group, m represents an integer of 2 to 4, n represents an integer of 0 to 2, m+n represents a valency of M. M is preferably Ti, Ar is preferably an aryl group having an organic group having 1 to 10 carbon atoms as a substituent, further preferably a phenyl group having the substituent, and especially preferably a phenyl group having an organic group having 1 to 10 carbon atoms as the substituent. SELECTED DRAWING: None COPYRIGHT: (C)2016,JPOandINPIT
The Hammett correlation between distyrylbenzene substituents and chemiluminescence efficiency providing various ρ-values for peroxyoxalate chemiluminescence of several oxalates
Maruyama, Takayuki,Narita, Susumu,Motoyoshiya, Jiro
, p. 222 - 231 (2013/03/13)
Peroxyoxalate chemiluminescence (PO-CL) was investigated using eight oxalates with various phenol moieties and the distyrylbenzene (DSB) fluorophores with various substituents. The ρ-values in the Hammett correlation between the substituent constants (σp+) of the DSBs and the singlet chemiexcitation yields (ΦS) for the PO-CL reactions varied from -0.50 to -1.01 depending on the oxalate structure, and the reactive oxalates tended to afford the higher absolute ρ-values but with a few exceptions. Based on the CIEEL mechanism, these experimental observations suggest that the aryloxy groups still remain in the 1,2-dioxetanones (DOTs), which are the postulated high-energy intermediates, and control the electronic properties of DOTs as electron-acceptors. The LUMO energies of the DOTs calculated by the ab initio method with a B3LYP/6-31g(d) basis set reveal that the lower the DOT-LUMO energies, the higher the absolute ρ-values were provided for the corresponding oxalates, as predicted by the frontier molecular orbital (FMO) theory. Thus, the chemical species interacting with the DSBs would be not unitary and will be DOTs.
