Catalytic vapour phase epoxidation of propene with nitrous oxide as an oxidant

Thömmes, Thomas; Zürcher, Sebastian; Wix, A.; Reitzmann, Andreas; Kraushaar‐Czarnetzki, Bettina

doi:10.1016/j.apcata.2006.10.051

Cited by 22 publications

(17 citation statements)

References 22 publications

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“…Green oxidants can be classified into three types: 1 hydroperoxides, which are produced in situ by reaction of O 2 with H 2 (in the gas or liquid phase) or with CO (in aqueous solution) over Au-based or Pd-Pt-based catalysts [7][8][9][10]; 2 N 2 O, which is by-produced in the nylon66 production process; this is a strong greenhouse warming gas and requires the use of iron-based catalysts for propene epoxidation [11][12][13][14][15][16][17][18]; and 3 molecular O 2 , which is the most abundant but difficult to control.…”

Section: Introductionmentioning

confidence: 99%

Gas-phase propene epoxidation over coinage metal catalysts

2011

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Propene oxide (PO) is a very important bulk chemical and is produced on a scale of about 7.5 million tons per year. In industry, PO is produced via multiple reaction steps in the liquid phase, using hazardous chlorine or costly organic hydroperoxides as oxidants. Accordingly, development of a simple and green process to produce PO has been desired. This paper presents an overview of one-step propene epoxidation in the gas phase over coinage metal catalysts with a mixture of O 2 and H 2 or with molecular O 2 alone as oxidant. Silver (Ag) and gold (Au) catalysts can catalyze propene epoxidation with a mixture of O 2 and H 2 , with high selectivity, whereas copper (Cu) catalysts cannot. In this reaction Au catalysts are much more active than Ag catalysts. All the coinage metals can catalyze propene epoxidation by molecular O 2 , but with selectivity usually below 60%. The valence states of Cu species and the sizes of Ag particles and Au particles are of crucial importance in PO synthesis.

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Section: Introductionmentioning

confidence: 99%

Gas-phase propene epoxidation over coinage metal catalysts

2011

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“…This process inevitably produces considerable amount of N2O accounting for nearly 8% of total anthropogenic emissions [1,3]. Some efficient processes for cutting down the amount of N2O exhausted into the atmosphere, such as catalytic decomposition [4][5][6][7][8], selective catalytic reduction (SCR) [9][10][11][12] or utilization as an oxidant in the synthesis of fine chemicals [13][14][15], have been developed by many scholars worldwide, but greater efforts are under way to develop more practical and efficient catalysis technologies to reduce the N2O emissions. The synthesis technology for KA oil is another problem encountered by the production of AA.…”

Section: Introductionmentioning

confidence: 99%

Visible light-triggered vanadium-substituted molybdophosphoric acids to catalyze liquid phase oxygenation of cyclohexane to KA oil by nitrous oxide

She

et al. 2016

Applied Catalysis B: Environmental

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“…18,20,22,24 The investigations by Moens et al 17 resulted in Rb 2 SO 4 being the best promoter. Cesium acetate was used in our recent works, 25,26 which led to better results than sodium acetate. 27 Previous studies with a catalyst containing 0.1 wt % Fe and 0.2 wt % Cs on SiO 2 revealed that low propene concentrations (1 vol %) and a surplus of N 2 O (15 vol %, rest: He) are necessary for high PO selectivities.…”

Section: Introductionmentioning

confidence: 98%

“…27 Previous studies with a catalyst containing 0.1 wt % Fe and 0.2 wt % Cs on SiO 2 revealed that low propene concentrations (1 vol %) and a surplus of N 2 O (15 vol %, rest: He) are necessary for high PO selectivities. 26,27 The product spectrum is known to a large extent, and a detailed reaction network was postulated, 25 which provided a basis for the development of a kinetic model. 26 The current study continues these investigations and is divided in two parts: In the first part, it will be shown how preparation and physicochemical characteristics (e.g., iron and alkaline content and calcination temperature) affect catalytic properties of the CsO x /FeO y /SiO 2 catalyst in the propene epoxidation using N 2 O as oxidant.…”

Section: Introductionmentioning

confidence: 99%

Catalytic Vapor Phase Epoxidation of Propene with Nitrous Oxide as an Oxidant: Investigations on Catalyst Composition and Reaction Conditions

Thömmes

Gräf

Reitzmann

et al. 2010

Ind. Eng. Chem. Res.

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The vapor phase epoxidation of propene with nitrous oxide (N 2 O) was experimentally investigated in a fixed bed reactor using different Cs x /Fe y /SiO 2 catalysts. This was done with a systematic approach which comprises the derivation of kinetic parameters for directly comparing catalyst performance. Therefore, kinetic measurements were made for each catalyst by variation of the residence time. It was found that the addition of an alkali promoter to the Fe y /SiO 2 catalyst is essential for the formation of propylene oxide and a proper alkali/Fe molar ratio is crucial for both activity and selectivity. Maxima in both activity and selectivity were observed for alkali/Fe ratios in the region 1.2-1.7. A further increase in activity without any loss in selectivity was obtained by adjusting the calcination temperature to 783 K. The conversion of PO was used as a tool to measure the product stability and a minimum reaction rate was also found for alkali/Fe ratios in the region 1.2-1.7. The promoter is responsible for the formation of active centers and it reduces surface acidity which leads to an increased stability of PO through the inhibition of the consecutive conversion. Maximum selectivities to PO of about 40% at 5-10% conversion were achieved at moderate reaction temperatures of 648 K. Because of parallel and consecutive formation of carbonaceous deposits on the catalyst, the catalyst deactivated within 2 h of operation to a remaining activity of around 40%. Neglecting the carbonaceous deposits as a reaction product and considering only the vapor phase products, PO selectivity is more than 75% at 5-10% propene conversion. The attempt to slow down the deactivation through the addition of supplementary gases (H 2 , O 2 , NH 3 , H 2 O) was partially successful, but unfortunately this is always accompanied by lower PO selectivity.

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Catalytic vapour phase epoxidation of propene with nitrous oxide as an oxidant

Cited by 22 publications

References 22 publications

Gas-phase propene epoxidation over coinage metal catalysts

Gas-phase propene epoxidation over coinage metal catalysts

Visible light-triggered vanadium-substituted molybdophosphoric acids to catalyze liquid phase oxygenation of cyclohexane to KA oil by nitrous oxide

Catalytic Vapor Phase Epoxidation of Propene with Nitrous Oxide as an Oxidant: Investigations on Catalyst Composition and Reaction Conditions

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