NaY and ion exchanged NaNH4Y zeolite with NH4NO3 were used as the support to prepare CuY cata‐lysts by a high temperature anhydrous interaction between the support and copper （II） acety‐lacetonate Cu（acac）2. The...NaY and ion exchanged NaNH4Y zeolite with NH4NO3 were used as the support to prepare CuY cata‐lysts by a high temperature anhydrous interaction between the support and copper （II） acety‐lacetonate Cu（acac）2. The catalysts were used for the oxidative carbonylation of methanol to dime‐thyl carbonate （DMC） at atmospheric pressure. The textural and acidic properties of NaNH4Y zeolite and the CuY catalysts were investigated by X‐ray diffraction, scanning electron microscopy, N2 ad‐sorption‐desorption, temperature programmed reduction of H2, X‐ray photoelectron spectroscopy and temperature programmed desorption of NH3. With increasing NH4NO3 concentration, the NH4＋exchange degree increased while the crystallinity of the zeolite remained intact. Crystalline CuO was formed when the NH4＋exchange degree of NaNH4Y was low, and the corresponding CuY catalyst showed low catalytic activity. With increasing of the NH4＋exchange degree of NaNH4Y, the content of surface bound Cu＋active centers increased and the catalytic activity of the corresponding CuY catalyst also increased. The surface bound Cu＋content reached its maximum when the NH4＋ex‐change degree of NaNH4Y reached towards saturation. The CuY exhibited optimal catalytic activity with 267.3 mg/（g·h） space time yield of DMC, 6.9%conversion of methanol, 68.5%selectivity of DMC.展开更多
In order to develop the catalysts with low corrosiveness for the oxidative carbonylation of methanol to dimethyl carbonate(DMC), Cu Br2 was selected as the metal source to prepare Cu coordination compounds, Cu(phen)Br...In order to develop the catalysts with low corrosiveness for the oxidative carbonylation of methanol to dimethyl carbonate(DMC), Cu Br2 was selected as the metal source to prepare Cu coordination compounds, Cu(phen)Br2,[Cu(phen)2Br]Br and [Cu(phen)3]Br2(phen = 1,10-phenanthroline). These complexes were characterized by thermogravimetric analysis and temperature-programmed reduction. Their catalytic performances were investigated. It was found that the metal coordination environments and thermal stability of the complexes played an important role in their catalytic activities. Cu(phen)Br2exhibited the highest activity due to the lowest steric hindrance, the most positions occupied by the bromide ions and the highest thermal stability. The turnover number was up to 47.6 DMC mol·(Cu mol)-1with selectivity of 92.8% under conditions of 120 °C, ratio of partial pressure of CO to O2 of 19:1(below the explosion limit of CO) and catalyst concentration of 0.011 mol·L-1.Furthermore, a plausible reaction mechanism was suggested on the basis of the experimental data.展开更多
基金supported by the National Natural Science Foundation of China (21276169)~~
文摘NaY and ion exchanged NaNH4Y zeolite with NH4NO3 were used as the support to prepare CuY cata‐lysts by a high temperature anhydrous interaction between the support and copper （II） acety‐lacetonate Cu（acac）2. The catalysts were used for the oxidative carbonylation of methanol to dime‐thyl carbonate （DMC） at atmospheric pressure. The textural and acidic properties of NaNH4Y zeolite and the CuY catalysts were investigated by X‐ray diffraction, scanning electron microscopy, N2 ad‐sorption‐desorption, temperature programmed reduction of H2, X‐ray photoelectron spectroscopy and temperature programmed desorption of NH3. With increasing NH4NO3 concentration, the NH4＋exchange degree increased while the crystallinity of the zeolite remained intact. Crystalline CuO was formed when the NH4＋exchange degree of NaNH4Y was low, and the corresponding CuY catalyst showed low catalytic activity. With increasing of the NH4＋exchange degree of NaNH4Y, the content of surface bound Cu＋active centers increased and the catalytic activity of the corresponding CuY catalyst also increased. The surface bound Cu＋content reached its maximum when the NH4＋ex‐change degree of NaNH4Y reached towards saturation. The CuY exhibited optimal catalytic activity with 267.3 mg/（g·h） space time yield of DMC, 6.9%conversion of methanol, 68.5%selectivity of DMC.
基金Supported by the National Natural Science Foundation of China(20936003,21276201)
文摘In order to develop the catalysts with low corrosiveness for the oxidative carbonylation of methanol to dimethyl carbonate(DMC), Cu Br2 was selected as the metal source to prepare Cu coordination compounds, Cu(phen)Br2,[Cu(phen)2Br]Br and [Cu(phen)3]Br2(phen = 1,10-phenanthroline). These complexes were characterized by thermogravimetric analysis and temperature-programmed reduction. Their catalytic performances were investigated. It was found that the metal coordination environments and thermal stability of the complexes played an important role in their catalytic activities. Cu(phen)Br2exhibited the highest activity due to the lowest steric hindrance, the most positions occupied by the bromide ions and the highest thermal stability. The turnover number was up to 47.6 DMC mol·(Cu mol)-1with selectivity of 92.8% under conditions of 120 °C, ratio of partial pressure of CO to O2 of 19:1(below the explosion limit of CO) and catalyst concentration of 0.011 mol·L-1.Furthermore, a plausible reaction mechanism was suggested on the basis of the experimental data.
基金supported by the National Natural Science Foundation of China(20936003)the Fundamental Research Funds for the Central Universities(China University of Mining and Technology,2010QNA11)the Innovation Funds for China University of Mining and Technology and High Tech Insititute of Lianyungang Xuwei new district(2011KDGXYJJ06)~~
