Role of Ce in supported Pd catalyst for oxidative carbonylation of phenol to diphenyl carbonate
(2.Tianjin Key Laboratory of Chemical Process Safety, Tianjin, China 300130)
【Abstract】A Pd-Ce-O/SiO2 catalyst with Ce as an auxiliary was prepared by the microemulsion method for oxidative carbonylation of phenol to synthesize diphenyl carbonate (DPC). The activity evaluation results showed that the catalyst performance increases with the increase in the amount of Ce. When the Ce/Pd molar ratio is 10/1, the phenol conversion rate is 64.4%, and the DPC selectivity is 83.4%. The XRD results show that part of Ce4+ enters into the PdO crystal lattice, and thus the electrons of deactivated Pd can easily be transferred to Ce. So the Pd-Ce-O/SiO2 catalyst can be easily regenerated and shows better performance. According to the above mentioned results, Pd-O/CeO2 was designed and prepared for oxidative carbonylation of phenol. However, unlike Pd-Ce-O/SiO2, Pd-O/CeO2 shows poor catalytic performance. The phenol conversion and DPC selectivity are only 24.0% and 23.3% respectively. The characterization results show that PdO is the main species of Pd on the surface of Pd-Ce-O/SiO2, but there is more PdO2 on Pd-O/CeO2. Because Pd(Ⅱ) is the active site for oxidative carbonylation, Pd-O/CeO2 exhibits inferior activity to Pd-Ce-O/SiO2. In addition, in the Pd-O/CeO2 catalyst the surface Pd content is lower than those in other catalysts because of the strong interaction between Pd species and CeO2. That is one of the reasons for the poor activity of Pd-O/CeO2.
【Keywords】 diphenyl carbonate; oxidative carbonylation; heterogeneous reaction; catalyst; support; ceria;
(Translated by WANG YX)
 Cui X M. Supply and demand status of polycarbonate at home and abroad and its development prospect analysis [J]. Technology & Economics in Petrochemicals, 2017, 33 (1): 18–23 (in Chinese).
 Gong J L, Ma X B, Wang S P. Phosgene-free approaches to catalytic synthesis of diphenyl carbonate and its intermediates [J]. Applied Catalysis A: General, 2007, 316: 1.
 Figueiredo M C, Trieu V, Eiden S, et al. Spectroscopic investigation of the electrosynthesis of diphenyl carbonate from CO and phenol on gold electrodes [J]. ACS Catalysis, 2018, 8 (4): 3087–3090.
 Wang Y J, Zhao X Q. Green Catalytic Process and Technology [M]. 2nd ed. Beijing: Chemical Industry Press, 2015 (in Chinese).
 Fu Q, Ouyang C, Zeng Y, et al. Progresses in the research on disproportionation of methyl phenyl carbonate [J]. Chemical Industry and Engineering Progress, 2017, 36 (8): 2748–2755 (in Chinese).
 Tang R Z, Chen T, Chen Y, et al. Core-shell TiO2@SiO2 catalyst for transesterification of dimethyl carbonate and phenol to diphenyl carbonate [J]. Chinese Journal of Catalysis, 2014, 35 (4): 457–461.
 Yang X, Ma X B, Wang S P, et al. Transesterification of dimethyl oxalate with phenol over TiO2/SiO2: catalyst screening and reaction optimization [J]. AIChE Journal, 2008, 54 (12): 3260–3272.
 Yin X, Zeng Y, Yao J, et al. Kinetic modeling of the transesterification reaction of dimethyl carbonate and phenol in the reactive distillation reactor [J]. Industrial & Engineering Chemistry Research, 2014, 53 (49): 19087–19093.
 Xue W, Zhang J C, Wang Y J, et al. Preparation of novel ultrafine embedded catalyst for oxidative carbonylation of phenol to diphenyl carbonate [J]. Journal of Chemical Industry and Engineering (China), 2004, 55 (12): 2076–2081 (in Chinese).
 Lu W, Du Z P, Yuan H, et al. Synthesis of diphenyl carbonate over the magnetic catalysts Pd/La1−xPbxMnO3 (x = 0.2–0.7) [J]. Chinese Journal of Chemical Engineering, 2013, 21: 8–13.
 Ronchin L, Vavasori A, Amadio E, et al. Oxidative carbonylation of phenols catalyzed by homogeneous and heterogeneous Pd precursors [J]. Journal of Molecular Catalysis A: Chemical, 2009, 298: 23–30.
 Yang X J, Han J Y, Du Z P, et al. Effects of Pb dopant on structure and activity of Pd/K-OMS-2 catalysts for heterogeneous oxidative carbonylation of phenol [J]. Catalysis Communications, 2010, 11: 643–646.
 Zhang Y L, Xiang S L, Wang G Q, et al. Preparation and application of coconut shell activated carbon immobilized palladium complexes [J]. Catalysis Science & Technology, 2014, 4: 1055–1063.
 Yin C F, Zhou J, Chen Q M, et al. Deactivation causes of supported palladium catalysts for the oxidative carbonylation of phenol [J]. Journal of Molecular Catalysis A: Chemical, 2016, 424: 377–383.
 Vavasori A, Toniolo L. Multistep electron-transfer catalytic system for the oxidative carbonylation of phenol to diphenyl carbonate [J]. Journal of Molecular Catalysis A: Chem., 1998, 139 (2/3): 109–119.
 Xue W, Zhang J C, Wang Y J, et al. Effect of promoter copper on the oxidative carbonylation of phenol over the ultrafine embedded catalyst Pd-Cu-O/SiO2 [J]. Journal of Molecular Catalysis A: Chemical, 2005, 232 (1/2): 77–81.
 Liang Y H, Guo H X, Chen H P, et al. Effect of doping cerium in the support of catalyst Pd-Co/Cu-CO-Mn mixed oxides on the oxidative carbonylation of phenol [J]. Chinese Journal of Chemical Engineering, 2009, 17 (3): 401–406.
 Zhang G X, Wu Y X, Ma P S, et al. Direct synthesis of diphenyl carbonate with heterogeneous catalysis reaction (Ⅸ): Effect of Ce loading methods on catalytic activity of catalyst [J]. Journal of Chemical Industry and Engineering (China), 2005, 56 (1): 82–87 (in Chinese).
 Yang X J, Yin C F, Han J Y, et al. Effect of oxygen species on the liquid product distribution in the oxidative carbonylation of phenol over Pd/M-OMS-2 catalysts [J]. Reac. Kinet. Mech. Cat., 2016, 117: 269–281.
 Spezzati G, Su Y Q, Hofmann J P, et al. Atomically dispersed Pd-0 species on CeO2 (111) as highly active sites for low-temperature CO oxidation [J]. ACS Catalysis, 2017, 7: 6887–6891.
 Liu Y F, Shen B X, Pi Z P, et al. Oxidation transferring mechanism of SO2 in FCC flue gas over CeO2 surface [J]. CIESC Journal, 2016, 67 (12): 5015–5023 (in Chinese).
 Yuan Y, Wang Z M, An H L, et al. Oxidative carbonylation of phenol with a Pd-O/CeO2-nanotube catalyst [J]. Chinese Journal of Catalysis, 2015, 36 (7): 1142–1152 (in Chinese).
 Luo J Y, Meng M, Xian H, et al. The nanomorphology-controlled palladium-support interaction and the catalytic performance of Pd/CeO2 catalysts [J]. Catalysis Letters, 2009, 133: 328–333.
 Brun M, Berthet A, Bertolini J C. XPS, AES and Auger parameter of Pd and PdO [J]. Journal of Electron Spectroscopy and Related Phenomena, 1999, 104: 55–60.
 Wu G W, Wu Y X, Ma P S, et al. Direct synthesis of diphenyl carbonate over heterogeneous catalyst: effects of structure of substituted perovskite carrier on the catalyst activities [J]. Frontiers of Chemical Science and Engineering in China, 2007, 1 (1): 59–64.
 Zhang Z R, Zhang S Y, Wan L, et al. Structure and surface chemical state of Pd/Ce containing hexagonal mesoporous silicas [J]. Journal of Chemical Industry and Engineering (China), 2007, 58 (3): 776–780 (in Chinese).
 Guimaraes A L, Dieguez D C, Schmal M. The effect of precursors salts on surface state of Pd/Al2O3 and Pd/CeO2/Al2O3 catalysts [J]. Annals of the Brazilian Academy of Sciences, 2004, 76 (4): 825–832.
 Luo M F, Hou Z Y, Yuan X X, et al. Characterization study of CeO2 supported Pd catalyst for low temperature carbon monoxide oxidation [J]. Catalysis Letters, 1998, 50 (3/4): 205–209.
 Sanchez M G, Gazquez J L. Oxygen vacancy model in strong metal–support interaction [J]. Journal of Catalysis, 1987, 104 (1): 120–135.
 Yang C, Ren J, Sun Y H. Study of CeO2- and La2O3-modified Pd/γ-Al2O3 catalyst for methanol decomposition at low temperature (I): Structure and properties of CeO2-modified Pd/γ-Al2O3 catalyst [J]. Chinese Journal of Catalysis, 2001, 22 (3): 283–286 (in Chinese).
 Zhu H Q, Qin Z F, Shan W J, et al. Pd/CeO2-TiO2 catalyst for CO oxidation at low temperature: a TPR study with H2 and CO as reducing agents [J]. Journal of Catalysis, 2004, 225 (2): 267–277.
 Cargnello M, Doan-Nguyen V V T, Gordon T R, et al. Control of metal nanocrystal size reveal metal–support interface role for ceria catalysts [J]. Science, 2013, 341 (6147): 771–773.
 Boronin A I, Slavinskaya E M, Danilova I G, et al. Investigation of palladium interaction with cerium oxide and its state in catalysts for low-temperature CO oxidation [J]. Catalysis Today, 2009, 144: 201–211.
 Wang Z, Qu Z P, Quan X, et al. Selective catalytic oxidation of ammonia to nitrogen over CuO-CeO2 mixed oxides prepared by surfactant–templated method [J]. Applied Catalysis B: Environmental, 2013, 134: 153–166.