Reduced coke formation during the gas phase oxidative dehydration of glycerol over ferrierite zeolites synthesized in fluoride medium

Santos, Maurício B. dos; Andrade, Heloysa Martins Carvalho; Mascarenhas, Artur J.S.

doi:10.1016/j.micromeso.2015.10.040

Cited by 27 publications

(18 citation statements)

References 32 publications

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“…S3 and Table S3). USY-P gives somewhat lower acid density compared to ZSM-22-P and ZSM-5-P. Beta-P contains the highest Lewis acidity, while the acid strength and acidity of FER-P is lower than that of the other zeolites in agreement with other reports [56]. The zeolites clearly show different catalytic performances in comparable reaction circumstances.…”

Section: Effect Of Pore Structure Of Zeolitessupporting

confidence: 89%

Shape selectivity vapor-phase conversion of lignin-derived 4-ethylphenol to phenol and ethylene over acidic aluminosilicates: Impact of acid properties and pore constraint

Liao

d’Halluin

Makshina

et al. 2018

Applied Catalysis B: Environmental

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Selective dealkylation of alkylphenols, the opposite reaction of the more commonly studied phenol alkylation, may represent an important reaction in the production of base chemicals like phenol and olefins from fossilized and raw lignocellulosic matter. This study reports the first thermodynamics and kinetics studies of the vaporphase conversion of ethylphenol (EP) over acidic γ-Al2O3, amorphous (ASA) and crystalline aluminosilicates (like ferrierite, ZSM-22, ZSM-5, beta, and USY) in the absence of hydrogen and noble metals, as a way to produce phenol and ethylene. The reaction was studied deliberately in presence of steam to get stable time on stream catalysis. The thermodynamic analysis shows an endothermal EP conversion to phenol and ethylene, favoured at high reaction temperature, while isomerisation, disproportionation and transalkylation are thermodynamically preferred at low temperature. The kinetic study examines the role of the catalytically active sites; it reveals the importance of site constraint on the activity, selectivity and stability, and shows the complex temperature dependency of the dealkylation. Both Brønsted and Lewis acid sites are active, but multifactor dependency (such as acid strength and site accessibility) complicates the establishment of simple quantitative relationships with the acid type. EP does not enter the micropores of ferrierite and ZSM-22, as suggested by adsorption experiments. Kinetics without significant diffusion limitations were obtained with ZSM-5, beta and USY. Thus, in absence of intracrystalline diffusion limitation (as verified by calculations using reported effective diffusivities, and substantiated by a comparably high apparent activation energy for all zeolites), the increased reaction turnover rate with increasing pore size from medium to large pore zeolites is largely explained by a change in reaction pathway (from monolecular to bimolecular) to convert EP to phenol and ethylene. A pathway proceeding through fast thermodynamically favourable bimolecular reactions occurs in the spatially non-constrained pores and crystal surface, whereas monomolecular reactions take place in the micropores of ZSM-5. Despite the lower rate, the selectivity over ZSM-5 strongly benefits from active site confinement, being responsible to achieve quantitative formation of phenol and ethylene from ethylphenol. The excellent performance of ZSM-5 thus accords with its shape selective property that avoids undesired side reactions such as the sterically demanding bimolecular reactions like disproportionation, transalkylation and CC cracking, and severe cokes formation.

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Section: Effect Of Pore Structure Of Zeolitessupporting

confidence: 89%

Shape selectivity vapor-phase conversion of lignin-derived 4-ethylphenol to phenol and ethylene over acidic aluminosilicates: Impact of acid properties and pore constraint

Liao

d’Halluin

Makshina

et al. 2018

Applied Catalysis B: Environmental

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“…It is also noticed that acrolein selectivity and yield of the catalysts show no obvious decrease with time on stream. Similar results were reported by dos Santos et al 26 Moreover, the trends of acrolein selectivity and yield of AlP and AlP-T samples calcined at different temperatures are not directly correlated with the trend of total acidities and Brønsted acid sites of the samples.…”

Section: Catalytic Activitysupporting

confidence: 88%

Catalytic Dehydration of Glycerol to Acrolein over Aluminum Phosphate Catalysts

Ding

Liu

et al. 2020

J. Braz. Chem. Soc.

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Gas phase conversion of glycerol to acrolein over a variety of aluminum phosphate (AlP) catalysts synthesized by a simple replacement reaction method with a variation in calcination temperature (300-700 °C, AlP-300, AlP-400, AlP-500, AlP-600, and AlP-700, respectively) has been investigated. The textural properties, acidities and coke contents of the samples were also determined. The catalysts were presented in an amorphous state when the AlP sample was calcined below 500 °C. Further increasing the calcination temperature promoted the formation of orthorhombic α-AlPO 4 crystal. The weak acid sites increased when the calcination temperature was raised from 300 to 500 °C. However, the weak acid sites decreased when the AlP was calcined above 500 °C. The acidity of the catalyst played a crucial role in the glycerol dehydration reaction. The maximum acrolein selectivity of 66% at 98% glycerol conversion was obtained over AlP-500 catalyst, due to the largest number of acid sites and appropriate textural properties. AlP-700 exhibited the lowest glycerol conversion, owing to the formation of orthorhombic α-AlPO 4 crystalline phase and the lowest amount of acid sites under high calcination temperature. The significant reduction in the acidity of the used sample led to a decrease of glycerol conversion.

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“…As a result, they influence the formation of the coke precursors and accumulation of the coke on the surface. [32,33] The pioneer work in the context of influence of pore size was made by Suprun et al [15] The authors found that the catalysts with larger pores exhibited a high activity but limited selectivity towards acrolein. On the other hand, catalysts with small micropores (5-6 Å) were less active but more selective.…”

Section: Pore Sizementioning

confidence: 99%

Tuning of Selectivity for Sustainable Production of Acrolein from Glycerol

Belousov

2021

ChemistrySelect

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The catalytic dehydration of glycerol into acrolein is a rapidly growing area of both scientific interest and technological importance. The main problem faced by researchers is enhancement of selectivity while maintaining the stability and activity of a catalyst. This minireview is centered on key approaches for tuning of selectivity: changing of physicochemical properties (type of acid sites, its amount, pore and channel size, and doping with noble metals) and selection of optimal reaction conditions (temperature, contact time, feedstock composition, co-feeding O 2 or air). This overview also proposes and discusses the use of metal-organic frameworks as novel catalysts to overcome the main challenges in the dehydration of glycerol.

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Reduced coke formation during the gas phase oxidative dehydration of glycerol over ferrierite zeolites synthesized in fluoride medium

Cited by 27 publications

References 32 publications

Shape selectivity vapor-phase conversion of lignin-derived 4-ethylphenol to phenol and ethylene over acidic aluminosilicates: Impact of acid properties and pore constraint

Shape selectivity vapor-phase conversion of lignin-derived 4-ethylphenol to phenol and ethylene over acidic aluminosilicates: Impact of acid properties and pore constraint

Catalytic Dehydration of Glycerol to Acrolein over Aluminum Phosphate Catalysts

Tuning of Selectivity for Sustainable Production of Acrolein from Glycerol

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