Vapour phase hydrocyclisation of levulinic acid to γ-valerolactone over supported Ni catalysts

Varkolu, Mohan; Velpula, Venkateshwarlu; Pramod, Chodimella Venkata; Raju, B. David; Rao, K. Srinivasa

doi:10.1039/c3cy01072d

Cited by 125 publications

(91 citation statements)

References 41 publications

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“…The data were fitted with Gaussian lineshapes; the peak position identifying the desorption temperature corresponding to different acid sites, classified according to their acid strength. The acid site distributions were classified by temperature range into weak or low energy acid sites (< 250 ºC), medium energy acid sites (250-400 ºC) and high energy acid sites (> 400 ºC) 51 . Table 5 shows the number and distribution of acid sites of the fresh CrO x /Al 2 O 3 catalyst and after ethylbenzene dehydrogenation at 3 and 6 h time-onstream determined by deconvolution of the NH 3 -TPD profiles.…”

Section: Effect Of Time-on-streammentioning

confidence: 99%

A new perspective on catalytic dehydrogenation of ethylbenzene: the influence of side-reactions on catalytic performance

Sanz

McMillan

McGregor

et al. 2015

Catal. Sci. Technol.

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eprints@whiterose.ac.uk https://eprints.whiterose.ac.uk/ Reuse Unless indicated otherwise, fulltext items are protected by copyright with all rights reserved. The copyright exception in section 29 of the Copyright, Designs and Patents Act 1988 allows the making of a single copy solely for the purpose of non-commercial research or private study within the limits of fair dealing. The publisher or other rights-holder may allow further reproduction and re-use of this version -refer to the White Rose Research Online record for this item. Where records identify the publisher as the copyright holder, users can verify any specific terms of use on the publisher's website. Takedown AbstractThe dehydrogenation of ethylbenzene to styrene is a highly important industrial reaction and the focus of significant research in order to optimise the selectivity to styrene and minimise catalyst deactivation. The reaction itself is a complex network of parallel and consecutive processes including cracking, steam-reforming and reverse water-gas shift (RWGS) in addition to dehydrogenation. The goal of this investigation is to decouple the major processes occurring and analyse how side-reactions affect both the equilibrium of ethylbenzene dehydrogenation and the surface chemistry of steam reforming activity over the reduced catalyst; and reverse water-gas shift reaction. Each of these processes plays a critical role in the observed catalytic activity.Notably, the presence of CO 2 evolved from the reduction of chromium by ethylbenzene and from the gasification of the deposited oxygen-functionalised coke results in the dehydrogenation reaction becoming partially oxidative, i.e. selectivity to styrene is enhanced by coupling of ethylbenzene dehydrogenation with the reverse water-gas shift reaction. Ethylbenzene cracking, coke gasification, steam-reforming and reverse water-gas-shift determine the relative quantities of CO 2 , CO, H 2 and H 2 O and hence affect the coupling of the reactions. Coke deposition during the cracking period lowers the catalyst acidity and may contribute to chromium reduction, hence diminishing the competition between acid and metal sites and favouring dehydrogenation activity.

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Section: Effect Of Time-on-streammentioning

confidence: 99%

A new perspective on catalytic dehydrogenation of ethylbenzene: the influence of side-reactions on catalytic performance

Sanz

McMillan

McGregor

et al. 2015

Catal. Sci. Technol.

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“…In our earlier publication [61], we have seen a similar observation with nitrobenzene-water mixture over an Ni/SBA-15 catalyst generating ~ 90% yield of aniline which indicated the robustness of SBA-15 as a support. As well, we noticed 22% yield of GVL with 37% levulinic acid conversion over 30 wt% Ni/ SiO 2 catalyst (1:1 molar ratio of levulinic acid and formic acid) [58]. This made us to focus on the hydrogenation of levulinic acid with formic acid as the hydrogen source (without external H 2 ).…”

Section: Effect Of Time-on-streammentioning

confidence: 99%

“…In order to avoid the deactivation phenomenon, we adopted various approaches not only coating of carbon on HZSM-5 [58] but also tried various supports [59]. From those results, we realized that the SiO 2 seems to be the best support for this reaction.…”

Section: Effect Of Time-on-streammentioning

confidence: 99%

Hydrogenation of levulinic acid with and without external hydrogen over Ni/SBA-15 catalyst

et al. 2018

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A series of Ni/SBA-15 catalysts were prepared by impregnation method for the hydrogenation of levulinic acid (LA) to γ-valerolactone in a fixed bed reactor at atmospheric pressure. The catalysts were characterized by XRD, TPR, AAS, Pulse chemisorption, SEM-EDAX, TEM, BET Surface area and XPS. The catalyst 30 wt% Ni/SBA-15 exhibited excellent catalytic performance (97% yield) at 250 °C due to the presence of superior number of active surface Ni species. While 30 wt% Ni/ SiO 2 catalyst showed lower catalytic activity (87% yield) at about similar conversion. The co-feeding of formic acid (FA) and water (impurities) with levulinic acid was also evaluated over 30 wt% Ni/SBA-15 which yielded excellent levulinic acid conversion. The noteworthy results were obtained at a molar ratio of FA/LA = 5. The constant catalytic activity during 10 h experiment with an external H 2 flow has showed the sturdiness of the Ni/SBA-15 catalyst. On the other hand, a slight decrease in conversion as well as yield during the time-on-stream in the absence of external H 2 flow was attributed to the accumulation of carbon species on the catalyst surface.

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“…Details of all the above techniques and procedures have already been described in our previous publication [11][12][13]. The synthesized catalysts were digested in aqua regia and conducted AAS (M/s.…”

Section: Catalyst Characterizationmentioning

confidence: 99%

“…Recently, supported nickel catalysts were reported for various organic transformations such as hydrogenation [11][12][13], steam reforming reactions [14], reductive amination of alcohols [15], hydrodechlorination [16,17], partial oxidation [18] and dry reforming of methane [19]. Among, hydrogenation is of great interest to both industry and academia.…”

Section: Introductionmentioning

confidence: 99%

Nitrobenzene hydrogenation over Ni/TiO2 catalyst in vapour phase at atmospheric pressure: influence of preparation method

et al. 2015

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Highly dispersed nickel nanoparticles on supports such as ZrO 2 and TiO 2 were prepared by reductive deposition method using hydrazine as reducing agent and applied to nitrobenzene hydrogenation. The highlight of this work is to compare the characteristics and activity of these catalysts with the catalysts of the same composition prepared by impregnation method. All the catalysts were characterized by various techniques such as BET, H 2 pulse chemisorption, TEM, XRD (crystalline nature), reduction behaviour (TPR) and state of nickel species (XPS). Ni/ TiO 2 catalyst prepared by reductive deposition method shows excellent conversion of nitrobenzene (99 %) to aniline. This is due to the presence of higher number of surface Ni species than other catalysts as evidenced by H 2 -chemisorption. TPR results reveal the formation of metallic Ni species in the reductive deposition method. XRD results suggest that the all catalytic systems show peaks corresponding to the supports only and not due to the metallic Ni because of its presence in highly dispersed form. The decrease in catalytic performance is observed during the time on stream might be due to coking of the catalyst by the reaction intermediate.

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Vapour phase hydrocyclisation of levulinic acid to γ-valerolactone over supported Ni catalysts

Abstract: A Ni/SiO2 catalyst is found to be effective for the hydrogenation of levulinic acid to yield γ-valerolactone with a quantitative yield in vapour phase conditions at atmospheric pressure without any additives.

Cited by 125 publications

References 41 publications

A new perspective on catalytic dehydrogenation of ethylbenzene: the influence of side-reactions on catalytic performance

A new perspective on catalytic dehydrogenation of ethylbenzene: the influence of side-reactions on catalytic performance

Hydrogenation of levulinic acid with and without external hydrogen over Ni/SBA-15 catalyst

Nitrobenzene hydrogenation over Ni/TiO2 catalyst in vapour phase at atmospheric pressure: influence of preparation method

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