3155-16-6Relevant academic research and scientific papers
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.
Synthesis of phenyl esters using SiO2-SO3H catalyst in conventional heating and microwave-irradiated esterification processes
Barbosa, Sandro L.,Ottone, Myrlene,De Freitas, Milton,Lima, Camila D.,Nelson, David L.,Clososki, Giuliano C.,Caires, Franco J.,Klein, Stanlei I.,Hurtado, Gabriela R.
, p. 3663 - 3668 (2019/05/08)
A SiO2-SO3H amorphous catalyst containing a small surface area of 115.0 m2g-1 and 1.32 mmol H+/g was prepared from fine construction sand and sodium carbonate and sulfonated with H2SO4. In a 10% (w/w) basis, it is very efficient for catalyzing the esterification of carboxylic acids with phenol. The reaction processes were performed using conventional heating and under microwave irradiation. The yields were higher in the microwave-irradiated esterification. The catalyst could be used for three esterification sequences in both processes.
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
Synthesis of arylacetates from benzylic alcohols and oxalate esters through decarboxylative coupling
Gruenberg, Matthias F.,Goossen, Lukas J.
supporting information, p. 7334 - 7337 (2013/06/27)
Follow that dream: By combining a reversible transesterification between benzylic alcohols and dialkyl oxalates with catalytic decarboxylation of the resulting esters, a regiospecific C-C-bond-forming reaction to give α-arylacetates was achieved. In the overall process, CO2 and a volatile alcohol are the only byproducts. Various α-arylacetates were thus synthesized in high yields from easily accessible starting materials in the presence of catalytic amounts of Pd(OAc)2, dppp, and DABCO (see scheme). Copyright
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.
Transesterification of diethyl oxalate with phenol over sol-gel MoO 3/TiO2 catalysts
Kotbagi, Trupti,Nguyen, Duy Luan,Lancelot, Christine,Lamonier, Carole,Thavornprasert, Kaew-Arpha,Wenli, Zhu,Capron, Micka?l,Jalowiecki-Duhamel, Louise,Umbarkar, Shubhangi,Dongare, Mohan,Dumeignil, Franck
scheme or table, p. 1467 - 1473 (2012/10/07)
The transesterification of diethyl oxalate (DEO) with phenol to form diphenyl oxalate (DPO) has been carried out in the liquid phase over very efficient MoO3/TiO2 solid-acid sol-gel catalysts. A selectivity of 100% with a remarkable maximum yield of 88% were obtained, which opens the route to downstream phosgene-free processes for the synthesis of polycarbonates. Interpretation of the results of various acidity measurements (NH3 and pyridine desorption, methanol oxidation as a probe reaction) allowed us to identify the catalytic sites as Lewis acid sites. Copyright
PROCESS FOR PREPARING DIARYL OXALATE
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Page/Page column 13, (2012/12/13)
Disclosed is a process for preparing a diaryl oxalate which comprises the step of transesterifying a dialkyl oxalate or/and an alkylaryl oxalate with an aryl alcohol in the presence of a tetra(aryloxy)titanium as a catalyst, wherein the tetra(aryloxy)titanium is fed into a reaction system of the transesterification as an aryl alcohol solution of the tetra(aryloxy)titanium which is prepared by reacting a tetraalkoxy titanium and an excess amount of the aryl alcohol and removing a by-producing alkyl alcohol.
Comparative study on the catalytic properties of amino-functionalized silica materials for the transesterification of dimethyl oxalate with phenol
Liu, Yan,Zhao, Guoming,Zhu, Wanchun,Wang, Jing,Liu, Gang,Zhang, Wenxiang,Jia, Mingjun
experimental part, p. 2254 - 2261 (2011/11/07)
A series of hybrid mesoporous MCM-41 materials containing different amino groups (such as 3-aminopropyl (AP-), (2-aminoethylamino)propyl (AAP-), or [2-(2-aminoethylamino)ethylamino] propyl (AEP-) group) were prepared by a post-grafting method, and characterized by means of X-ray powder diffraction (XRD), N2 adsorption, Fourier transform-infrared spectroscopy (FT-IR) and temperature-programmed desorption of CO2 (CO2-TPD). The catalytic properties of these hybrid materials were investigated for the transesterification of dimethyl oxalate with phenol. All the samples were active for the transesterification. Among them, the sample AEP-MCM-41 exhibited the highest activity under test conditions. And only a slight decrease in activity could be observed after few runs, indicating the good recyclability of this catalyst. Notably, the activity of the used catalyst could be regenerated by simple treatment with diluted basic agents under mild conditions. Moreover, effects of the density and the basic strength of the amino groups on the catalytic properties were taken into consideration for understanding the reaction mechanism and the possible formation route of the by-product anisole.
Photochemical formation of novel pyrrolo[3,2-b]-6,7-benzobicyclo[3.2.1]octa-2,6-diene
Basaric, Nikola,Marinic, Zeljko,Sindler-Kulyk, Marija
, p. 7524 - 7527 (2007/10/03)
The first synthesis of 1,4,9,10-tetrahydro-4,9-methanobenzo[4,5]cyclohepta[1,2-b]pyrrole (11) was achieved by the photochemical intramolecular (2 + 2] cycloaddition of N-phenoxycarbonyl- (5a) and N-ethoxycarbonyl-2-[2-(2-vinylphenyl)]pyrrole (6a), respectively, followed by basic hydrolysis of the isolated N-substituted 1,4,9,10-tetrahydro-4,9-methanobenzo[4,5]cyclohepta[1,2-b]pyrroles (10a, 10b). Some competitively formed products were also isolated.
PROCESS FOR PRODUCING POLYCARBONATE
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, (2008/06/13)
A process for preparing polycarbonate is composed of the steps of transesterifying a dialkyl oxalate and a phenolic compound to give a diaryl oxalate; decarbonylating the diaryl oxalate to give a diaryl carbonate; reacting the diaryl carbonate with a polyvalent hydroxyl compound in the presence of a catalyst containing an amine compound or an ammonium compound to give the polycarbonate, removing a phenolic by-product/amine by-product mixture; collecting the mixture; purifying the mixture so that the amount of the amine by-product in the mixture is reduced to give a phenolic by-product mixture not containing the amine by-product in an amount of more than 600 ppm; and, utilizing thus purified phenolic mixture as a whole or a part of the phenolic compound in the first step.
