Epoxidation of propylene to propylene oxide with molecular oxygen over Sb2O3–CuO–NaCl/SiO2 catalysts
TL;DR: In this paper, a trimetallic system was optimized for PO formation by varying the Sb:Cu:Na ratios, total metal loadings and calcination temperatures, and the highest performing catalyst achieved 40-45% PO selectivity with 0.4-0.7% conversion without a co-feeding gas.
About: This article is published in Journal of Industrial and Engineering Chemistry.The article was published on 2015-12-25. It has received 14 citations till now. The article focuses on the topics: Propylene oxide & Catalysis.
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TL;DR: Propylene oxide (PO) is a versatile chemical, mainly used in the synthesis of polyurethane plastics as mentioned in this paper, and it can be epoxidized using molecular oxygen to replace the tedious current synthesis protoco...
Abstract: Propylene oxide (PO) is a versatile chemical, mainly used in the synthesis of polyurethane plastics. Propylene epoxidation using molecular oxygen could replace the tedious current synthesis protoco...
62 citations
TL;DR: RuO2-CuO/SiO2 catalysts doped with Cs2O and TiO2 were investigated for the direct gas phase epoxidation of propylene to propylene oxide (PO) using molecular oxygen under atmospheric pressure as mentioned in this paper.
Abstract: RuO2–CuO/SiO2 catalysts doped with Cs2O and TiO2 were investigated for the direct gas phase epoxidation of propylene to propylene oxide (PO) using molecular oxygen under atmospheric pressure. The optimal catalyst was achieved at Ru/Cu/Cs/Ti = 8.3/4.2/0.6/0.8 by weight and total metal loading of 21 wt% on SiO2 support. NH3 and CO2 temperature programmed desorption measurements of RuO2–CuO/SiO2 catalyst modified with Cs2O showed that the surface's acidity decreased, resulting in enhanced PO selectivity. The addition of TiO2 increased the PO formation rate by promoting the synergy effect between RuO2 and CuO. Using the Box–Behnken design of experiments on the RuO2–CuO–Cs2O–TiO2/SiO2 catalyst, an extraordinarily high optimal PO formation rate of 3015 gPO h−1 kgcat−1 was obtained with a feed comprised of O2/C3H6 at a volume ratio of 3.1 and (O2 + C3H6)/He at a volume ratio of 0.26, all at 272 °C and 34 cm3 min−1. To the knowledge of the authors, this is the highest PO formation rate ever reported for direct propylene epoxidation via O2.
15 citations
TL;DR: In this article, multi-metallic RuO 2 -CuO-NaCl-TeO2 -MnO x /SiO 2 catalysts were investigated for the epoxidation of propylene to propylene oxide (PO) using O 2 under atmospheric pressure.
15 citations
TL;DR: In this paper, the epoxidation of propylene using Ag catalysts supported on nonporous or low surface area supports such as α-Al3O2, CaCO3, TiO2 rutile, SiO2 and ZrO2 was thoroughly investigated.
8 citations
References
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TL;DR: A review of the latest advances in the catalysis research on Au is presented in this article, focusing on Au/TiO 2 together with the effect of preparation conditions and pretreatments.
Abstract: Gold catalysts have recently been attracting rapidly growing interests due to their potential applicabilities to many reactions of both industrial and environmental importance. This article reviews the latest advances in the catalysis research on Au. For low-temperature CO oxidation mechanistic arguments are summarized, focusing on Au/TiO 2 together with the effect of preparation conditions and pretreatments. The quantum size effect is also discussed in the adsorption and reaction of CO over Au clusters smaller than 2 nm in diameter. In addition, recent developments are introduced in the epoxidation of propylene, water-gas-shift reaction, hydrogenation of unsaturated hydrocarbons, and liquid-phase selective oxidation. The role of perimeter interface between Au particles and the support is emphasized as a unique reaction site for the reactants adsorbed separately, one on Au and another on the support surfaces.
1,311 citations
TL;DR: In this article, it was shown that propylene adsorbed on a gold surface may react with oxygen species formed at the perimeter interface between the gold particles and the TiO2support through the reaction of oxygen with hydrogen.
1,076 citations
792 citations
TL;DR: It is found that unpromoted, size-selected Ag3 clusters and ~3.5-nanometer Ag nanoparticles on alumina supports can catalyze this reaction with only a negligible amount of carbon dioxide formation and with high activity at low temperatures.
Abstract: Production of the industrial chemical propylene oxide is energy-intensive and environmentally unfriendly. Catalysts based on bulk silver surfaces with direct propylene epoxidation by molecular oxygen have not resolved these problems because of substantial formation of carbon dioxide. We found that unpromoted, size-selected Ag3 clusters and ~3.5-nanometer Ag nanoparticles on alumina supports can catalyze this reaction with only a negligible amount of carbon dioxide formation and with high activity at low temperatures. Density functional calculations show that, relative to extended silver surfaces, oxidized silver trimers are more active and selective for epoxidation because of the open-shell nature of their electronic structure. The results suggest that new architectures based on ultrasmall silver particles may provide highly efficient catalysts for propylene epoxidation.
735 citations