Kinetics of ethylene epoxidation on a silver catalyst

Ghazali, Sheikh Ahmad Izaddin Sheikh Mohd; Park, D.W.; Gau, G.

doi:10.1016/0166-9834(83)80264-4

Cited by 24 publications

(10 citation statements)

References 22 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Excess oxygen was used in all the experiments, so that the rate expressions for epoxidation and deep oxidation to C 0 2 were given by Eqs. (7), (8) and (9). Finally, in agreement with previous studies (Sachtler et al, 1981;Cant and Hall, 1978) it was found that for no ethylene oxide in the feed stream and for low conversions (<25%) r, was small enough to be neglected.…”

Section: Measurement Of Surface Oxygen Activitysupporting

confidence: 88%

“…The inhibiting effect of reaction products and other species on the reaction yield and selectivity has also been studied extensively (Voge and Adams, 1967; Sachtler el al., 1981; Cant and Hall, 1978;Hayes, 1960). Nevertheless, despite the large number of investigators and some very interesting recent experimental findings (Wachs and Kelemen, 1981;Ghazali et al, 1983;Campbell and Paffett, 1984;Haul et al, 1984;Grant and Lambert, 1985(i), 1985(ii)) no generally accepted reaction mechanism has been established. The very wide scatter of the published parameters make it impossible to draw unambiguous conclusions on the mechanism from such data.…”

Section: Introductionmentioning

confidence: 90%

“…and(9) as follows: Downloaded by [Columbia University] at 16:41 03 February 2015where the values of K , , K,, K,, KETo and K , are the same as those shown in Eqs. (10) through(14).In presence of excess ethylene oxide the rates rco, and rETo can be written as:rco, = rz + r3 = K 2 K~~P~~ + K 3 K ET O ( P E T 0 ) 2 1 + KETPET + KETO(~'ETO), and FIGURE 9 Predicted rates of ethylene oxide formation, ethylene oxide oxidation and ethylene deep oxidation at 400°C.…”

mentioning

confidence: 96%

See 2 more Smart Citations

Ethylene Oxidation on Silver Catalysts: Effect of Ethylene Oxide and of External Transfer Limitations

Stoukides

Pavlou

1986

Chemical Engineering Communications

View full text Add to dashboard Cite

Ethylene oxidation to ethylene oxide and to carbon dioxide over silver catalysts was studied in a CSTR. The effects of two factors on the catalyst performance were examined. The first was the presence of excess ethylene oxide in the feed. A kinetic model was introduced which assumed that ethylene and ethylene oxide compete for the same sites on the catalyst surface. This model provided reasonable quantitative agreement with kinetic and potentiometric measurements. The second factor that was studied was the presence of external heat and mass transfer limitations. It was found that such limitations cause a significant decrease of the selectivity to ethylene oxide. This decrease is a result of the temperature difference between the catalyst surface and the bulk of the gas phase and of the fact that the activation energy of ethylene combustion is greater than that of ethylene epoxidation. The contribution of other factors such as inhibition by CO, or possible incomplete mixing in the reactor is shown to be insignificant.

show abstract

Section: Measurement Of Surface Oxygen Activitysupporting

confidence: 88%

Section: Introductionmentioning

confidence: 90%

mentioning

confidence: 96%

See 1 more Smart Citation

Ethylene Oxidation on Silver Catalysts: Effect of Ethylene Oxide and of External Transfer Limitations

Stoukides

Pavlou

1986

Chemical Engineering Communications

View full text Add to dashboard Cite

show abstract

“…Although several studies contained promoted Ag catalysts, ,,, rate expressions incorporating the effect of promoters have not been discussed or reported. In the future, comprehensive rate expressions should be developed to also account for the impact of the promoters on the kinetics of ethylene oxidation by Ag catalysts.…”

Section: Kineticsmentioning

confidence: 99%

Overview of Selective Oxidation of Ethylene to Ethylene Oxide by Ag Catalysts

et al. 2019

View full text Add to dashboard Cite

Ethylene oxidation by Ag catalysts has been extensively investigated over the past few decades, but many key fundamental issues about this important catalytic system are still unresolved. This overview of the selective oxidation of ethylene to ethylene oxide by Ag catalysts critically examines the experimental and theoretical literature of this complex catalytic system: (i) the surface chemistry of silver catalysts (single crystal, powder/foil, and supported Ag/α-Al2O3), (ii) the role of promoters, (iii) the reaction kinetics, (iv) the reaction mechanism, (v) density functional theory (DFT), and (vi) microkinetic modeling. Only in the past few years have the modern catalysis research tools of in situ/operando spectroscopy and DFT calculations been applied to begin establishing fundamental structure–activity/selectivity relationships. This overview of the ethylene oxidation reaction by Ag catalysts covers what is known and what issues still need to be determined to advance the rational design of this important catalytic system.

show abstract

“…The rate of EO oxidation (reaction 3) is very low, thus, the third reaction is often neglected. The second reaction is thermodynamically favorable and this is the reason for the low selectivity of EO production .…”

Section: Introductionmentioning

confidence: 99%

Influence of the specific surface area and silver crystallite size of mesoporous Ag/SrTiO₃ on the selectivity enhancement of ethylene oxide production

Adhami

Esfahany

Eränen

et al. 2019

J of Chemical Tech & Biotech

View full text Add to dashboard Cite

Background Ethylene oxide, which is industrially produced by ethylene epoxidation, is an important versatile chemical intermediate, thus its selectivity enhancement can bring substantial economic profits. In this work, the effects of two important, but still debatable, factors, i.e. catalyst specific surface area and active phase crystallite size, on the catalyst selectivity enhancement were investigated. Surfactant assisted sol–gel method with good control ability on the pores structure was selected to produce mesoporous strontium titanate (SrTiO3) nanocrystals with various specific surface area. The SrTiO3 nanocrystals were used as the supports of silver (Ag) for ethylene epoxidation. Results The Ag/SrTiO3 catalysts with various surface areas were obtained by changing the surfactant‐alkoxide ratio and the calcination time. The ethylene oxide selectivity of the prepared catalysts was examined in a laboratory‐scale fixed bed reactor. The best performance was observed at the lowest surfactant–alkoxide ratio of 0.2 and calcination time of 4 h, with the surface area of 1.7 m2/g and Ag crystallite size of 15 nm. Conclusion The best catalyst selectivity was observed at the lowest surface area and the highest average Ag crystallite size. In this condition, the selectivity of the Ag/SrTiO3 catalyst without any modifier was superior to a commercial Ag/Al2O3 catalyst with 3.7m2/g surface area and alkaline earth metal modifiers. © 2019 Society of Chemical Industry

show abstract

Kinetics of ethylene epoxidation on a silver catalyst

Cited by 24 publications

References 22 publications

Ethylene Oxidation on Silver Catalysts: Effect of Ethylene Oxide and of External Transfer Limitations

Ethylene Oxidation on Silver Catalysts: Effect of Ethylene Oxide and of External Transfer Limitations

Overview of Selective Oxidation of Ethylene to Ethylene Oxide by Ag Catalysts

Influence of the specific surface area and silver crystallite size of mesoporous Ag/SrTiO₃ on the selectivity enhancement of ethylene oxide production

Contact Info

Product

Resources

About

Kinetics of ethylene epoxidation on a silver catalyst

Cited by 24 publications

References 22 publications

Ethylene Oxidation on Silver Catalysts: Effect of Ethylene Oxide and of External Transfer Limitations

Ethylene Oxidation on Silver Catalysts: Effect of Ethylene Oxide and of External Transfer Limitations

Overview of Selective Oxidation of Ethylene to Ethylene Oxide by Ag Catalysts

Influence of the specific surface area and silver crystallite size of mesoporous Ag/SrTiO3 on the selectivity enhancement of ethylene oxide production

Contact Info

Product

Resources

About

Influence of the specific surface area and silver crystallite size of mesoporous Ag/SrTiO₃ on the selectivity enhancement of ethylene oxide production