Epoxidation of propylene on NaCl-modified silver catalysts with air as the oxidant

Lu, Jiqing; Luo, Ming; Lei, Hao; Li, Can

doi:10.1016/s0926-860x(02)00062-5

Cited by 105 publications

(77 citation statements)

References 29 publications

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“…The low PO selectivity arising because of allylic hydrogen of propene has been tried to enhance with different support materials and modifiers and even bimetallic systems such as Au, Cu, Ni etc. catalysts [11][12][13][14][15][16][17][18][19][20][21][22][23]. Generally it is reported that larger (max.…”

Section: Introductionmentioning

confidence: 97%

Epoxidation of Propene by High-Throughput Screening Method Over Combinatorially Prepared Cu Catalysts Supported on High and Low Surface Area Silica

et al. 2012

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Gas phase epoxidation of propene using molecular oxygen was studied by use of a high-throughput testing technique. A large number of catalysts including promoted and un-promoted Cu were synthesized in a much faster combinatorial fashion using a sol-gel method. Metal catalysts supported on high and low surface area silica were tested and ranked in a high-throughput activity and selectivity testing apparatus at different experimental conditions such as reaction temperature and reactant gas ratio. The amount of Cu loading and the addition of alkali promoters such as K and Li resulted in different tendencies in consumption rate for both silica materials. The maximum PO production rate was obtained as 25.82 lmol/g/ cat./min (2.90 % conv. and 20.49 % selectivity) for 3 % Cu-2.25 % K catalyst supported on high surface area silica. There was no noticeable difference in structural and chemical properties of catalysts after modification with K when examined by XRD and TEM; however, the overall activation energy of un-modified catalysts (92 kJ/mol) decreased to 71 kJ/mol for K-modified catalyst. There was negligible difference between the activation energies calculated for PO production (75 vs. 77 kJ/mol).

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Section: Introductionmentioning

confidence: 97%

Epoxidation of Propene by High-Throughput Screening Method Over Combinatorially Prepared Cu Catalysts Supported on High and Low Surface Area Silica

et al. 2012

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“…The Cl 2p spectra of NaCl also have two peaks at the same positions, and these two peaks indicate chloride. As the peak moves to the left, it suggests the formation of organic Cl [31,35]. The peak moves to the right from 200 • C to 400 • C, implying that binding to chloride rather than binding with organic matter increases, and this can explain the decrease in the amount of volatilized components as the pyrolysis temperature increases.…”

Section: Change Of Carbon and Salt According To The Pyrolysis Temperamentioning

confidence: 97%

Recycling Possibility of the Salty Food Waste by Pyrolysis and Water Scrubbing

Lee

Kim

et al. 2017

Energies

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Abstract:Salty food waste is difficult to manage with previous methods such as composting, anaerobic digestion, and incineration, due to the hindrance of salt and the additional burden to handle high concentrations of organic wastewater produced when raw materials are cleaned. This study presents a possibility of recycling food waste as fuel without the burden of treatment washing with water by pyrolyzing and scrubbing. For this purpose, salty food waste with 3% NaCl was made using 10 materials and pyrolysis was conducted at temperature range between 200-400 • C. The result was drawn from elementary analysis (EA), X-ray photoelectron spectroscopy (XPS) analysis, atomic absorption spectrophotometry (AAS) analysis, water quality analysis and calorific value analysis of char, washed char, and washing water. The result of the EA showed that NaCl in food waste could be volatilized at a low pyrolysis temperature of 200-300 • C and it could be concentrated and fixed in char at a high pyrolysis temperature of 300-400 • C. The XPS analysis result showed that NaCl existed in form of chloride. Through the Na content result of the AAS analysis, NaCl remaining in char after water scrubbing was determined to be less than 2%. As the pyrolysis temperature increased, the chemical oxygen demand (COD) value of scrubbing water decreased rapidly, but the total phosphorus and nitrogen contents decreased gradually. The cleaned pyrolysis char showed an increase of higher heating value (HHV) approximately 3667-9920 J/g due to the removal of salt from the char and, especially at 300-400 • C, showed a similar HHV with normal fossil fuels. In conclusion, salty food waste, which is pyrolyzed at a temperature of 300-400 • C and cleaned by water, can be utilized as high-energy refuse derived fuel (RDF), without adverse effects, due to the volatilization of Cl and an additional process of contaminated water.

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“…Yang et al [28] reported the similar results by investigating the modified Ag catalyst with Re for the epoxidation of ethylene, and found that adding Re into Ag catalyst led to Ag electron-deficient and Re 7+ transforming to Re 7Àd . Lu et al [29] reported that a part of Ag atoms in the NaCl-modified Ag catalyst existed as cation, and the high oxidative state of Ag was favorable to produce electrophilic oxygen species. Therefore, Y 2 O 3 played a role of electron-type promoter that could strongly polarize nearby electron cloud of Ag, which made the absorbed oxygen hold proper electrophilic character and was beneficial to the olefinic carbon of propylene converting to PO.…”

Section: Xpsmentioning

confidence: 99%

Epoxidation of Propylene by Molecular Oxygen Over the Ag–Y2O3–K2O/α-Al2O3 Catalyst

et al. 2007

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The Ag/a-Al 2 O 3 catalyst modified with rare earth metal oxide (Y 2 O 3 ) and alkali metal oxide (K 2 O) for the epoxidation of propylene by molecular oxygen were prepared and characterized by TG-DTA, XRD and XPS. The results show that a small quantity of Y 2 O 3 added plays a role of electron and structure-type promoters, and can change the binding energies of Ag3d and restrain the sintering of Ag crystallites during catalyst preparation. The effects of promoters loading, Ag loading, reaction temperature, and calcination atmosphere on the performance of Ag catalyst were investigated. The results show that the loadings of K 2 O, Y 2 O 3 and Ag, and reaction temperature affect obviously the catalytic performance of Ag-Y 2 O 3 -K 2 O/a-Al 2 O 3 for the epoxidation of propylene to propylene oxide. Under the reaction conditions of 0.1 MPa, 245°C, GHSV of 2000 h À1 and the feed gas of 20%C 3 H 6 /8%O 2 / N 2 , the conversion of propylene of 4% and the selectivity to propylene oxide of 46.8% were achieved over the 20%Ag-0.1%Y 2 O 3 -0.1%K 2 O/a-Al 2 O 3 catalyst.

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Epoxidation of propylene on NaCl-modified silver catalysts with air as the oxidant

Cited by 105 publications

References 29 publications

Epoxidation of Propene by High-Throughput Screening Method Over Combinatorially Prepared Cu Catalysts Supported on High and Low Surface Area Silica

Epoxidation of Propene by High-Throughput Screening Method Over Combinatorially Prepared Cu Catalysts Supported on High and Low Surface Area Silica

Recycling Possibility of the Salty Food Waste by Pyrolysis and Water Scrubbing

Epoxidation of Propylene by Molecular Oxygen Over the Ag–Y2O3–K2O/α-Al2O3 Catalyst

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