The role of La in improving the selectivity to cyclohexene of Ru catalyst for hydrogenation of benzene

Sun, Haijie; Dong, Yingying; Li, Shuaihui; Jiang, Hou-Bing; Zhang, Yuanxin; Liu, Zhongyi; Liu, Shouchang

doi:10.1016/j.molcata.2012.12.001

Cited by 15 publications

(7 citation statements)

References 31 publications

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“…They found that Ce existed as Ce 3+ , which may transfer electrons from Ru and enhance the hydrophilicity of the catalyst surface, leading to the improvement of selectivity over Ru catalyst. In addition, Ru-M (M = Fe [24], Mn [24], Zn [24], La [25] and Ce [26]) catalysts were synthesized by Sun 2 were observed, which could considerably increase the selectivity towards cyclohexene production over Ru catalyst.…”

Section: Introductionmentioning

confidence: 99%

Investigation on Mn3O4 Coated Ru Nanoparticles for Partial Hydrogenation of Benzene towards Cyclohexene Production Using ZnSO4, MnSO4 and FeSO4 as Reaction Additives

et al. 2020

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Mn3O4 coated Ru nanoparticles (Ru@Mn3O4) were synthesized via a precipitation-reduction-gel method. The prepared catalysts were evaluated for partial hydrogenation of benzene towards cyclohexene generation by applying ZnSO4, MnSO4 and FeSO4 as reaction additives. The fresh and spent catalysts were thoroughly characterized by XRD, X ray fluorescence (XRF), XPS, TEM and N2-physicalsorption in order to understand the promotion effect of Mn3O4 as the modifier as well as ZnSO4, MnSO4 and FeSO4 as reaction additives. It was found that 72.0% of benzene conversion and 79.2% of cyclohexene selectivity was achieved after 25 min of reaction time over Ru@Mn3O4 with a molar ratio of Mn/Ru being 0.46. This can be rationalized in terms of the formed (Zn(OH)2)3(ZnSO4)(H2O)3 on the Ru surface from the reaction between Mn3O4 and the added ZnSO4. Furthermore, Fe2+ and Fe3+ compounds could be generated and adsorbed on the surface of Ru@Mn3O4 when FeSO4 is applied as a reaction additive. The most electrons were transferred from Ru to Fe, resulting in that lowest benzene conversion of 1.5% and the highest cyclohexene selectivity of 92.2% after 25 min of catalytic experiment. On the other hand, by utilizing MnSO4 as an additive, no electrons transfer was observed between Ru and Mn, which lead to the complete hydrogenation of benzene towards cyclohexane within 5 min. In comparison, moderate amount of electrons were transferred from Ru to Zn2+ in (Zn(OH)2)3(ZnSO4)(H2O)3 when ZnSO4 is used as a reaction additive, and the highest cyclohexene yield of 57.0% was obtained within 25 min of reaction time.

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Section: Introductionmentioning

confidence: 99%

Investigation on Mn3O4 Coated Ru Nanoparticles for Partial Hydrogenation of Benzene towards Cyclohexene Production Using ZnSO4, MnSO4 and FeSO4 as Reaction Additives

et al. 2020

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“…Meanwhile, in contrast, the selectivity towards cyclohexene formation grows. In addition, cyclohexene yield of 60.4% was obtained when the molar ratio of ZnO to Ru is 0.19, which is one of the highest yields of cyclohexene reported by far [33][34][35]. Furthermore, as can be observed in Figure 7, no cyclohexene was detected without any additives.…”

Section: Effects Of Zno and Znso4mentioning

confidence: 72%

Selective Hydrogenation of Benzene to Cyclohexene over Monometallic Ru Catalysts: Investigation of ZnO and ZnSO4 as Reaction Additives as Well as Particle Size Effect

Sun

Chen

et al. 2018

Catalysts

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Monometallic Ru catalysts with different particle size were prepared via a precipitation method and reduced at different temperatures. In addition, their catalytic activity towards cyclohexene formation from selective hydrogenation of benzene was investigated. With the utilization of ZnO and ZnSO 4 as reaction additives, (Zn(OH) 2) 3 (ZnSO 4)(H 2 O) 3 could be generated and chemisorbed on the Ru surface, which played a crucial role on increasing the selectivity to cyclohexene and retarding the catalytic activity towards benzene conversion. Interestingly, without addition of ZnO and ZnSO 4 , no cyclohexene was observed over all tested Ru catalysts with different particle sizes. This suggested that particle size plays no role in cyclohexene synthesis from selective hydrogenation of benzene over the pure monometallic Ru catalysts in the absence of ZnO and ZnSO 4. On the other hand, when both ZnO and ZnSO 4 were applied, surface n(Zn 2+)/n(Ru) molar ratio increased with increasing particle size of the monometallic Ru catalysts after catalytic experiments, demonstrating that the content of chemisorbed (Zn(OH) 2) 3 (ZnSO 4)(H 2 O) 3 on Ru catalysts surface is enhanced under such a circumstance. More importantly, the maximum cyclohexene yield obtained over monometallic Ru catalysts showed a volcanic-type variation with increasing particle size of Ru from 3.6 nm to 5.6 nm. When the particle size of the monometallic Ru catalyst was 4.7 nm, the highest cyclohexene yield of 60.4% was achieved with an optimum n(ZnO)/n(Ru) ratio of 0.19:1 in the presence of 0.62 mol•dm −3 ZnSO 4 within 25 min of catalytic experiments at 423 K under 5.0 MPa of H 2. In addition, no decrease of catalytic activity towards cyclohexene generation was observed over this catalyst after 10 catalytic experiments without any regeneration.

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“…Besides the organic additives, we have evaluated the promotion effect of transition metals (e.g., Cr, Mn, Fe, Co, Ni, Cu, and Zn) as well as the rare-earth metal (e.g., La and Ce) on selective hydrogenation of benzene to cyclohexene over Ru-based catalysts as well. ,,− As demonstrated in Table , in comparison to the yield of cyclohexene achieved over pure Ru catalyst (e.g., Y max = 33.0%), the yield of cyclohexene drastically increased with addition of Mn, Fe, Zn, La, and Ce, over which maximum cyclohexene yield of 55.3, 56.7, 53.4, 59.5, and 57.4% was obtained, respectively. Conversely, Cr, Co, Ni and Cu exhibit no obvious promotion effect for Ru catalysts toward cyclohexene formation, over which maximum cyclohexene yield of 35.8, 43.2, 36.1, and 46.1% was achieved, respectively.…”

Section: Selective Hydrogenation Of Benzene To Cyclohexene Over Nanos...mentioning

confidence: 99%

Selective Hydrogenation of Benzene: Progress of Understanding for the Ru-Based Catalytic System Design

Chen

Sun

Peng

et al. 2019

Ind. Eng. Chem. Res.

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Selective hydrogenation of benzene toward cyclohexene is an economically interesting and technically challenging reaction, and catalytic system design is the kernel for selective hydrogenation of benzene. In this work, we mainly summarize our theoretical and experimental approaches, based on enhancing the yield of cyclohexene over Ru catalysts, to get deeper understanding for designing the catalytic system. Basic thermodynamics and kinetic study, amorphous Ru-M-B-based catalytic systems, Ru-Zn system (including both organic additives and inorganic additives) and Ru-M catalytic system were mainly discussed. With the gradually deeper understanding, a finely controlled nonadditive Ru-BZSS catalytic system was developed. Finally, we review the faced challenges in the current work and possible opportunities in the future research. We believe that the proposed understanding of catalysts for selective hydrogenation of benzene will provide inspiration on catalytic system designing for selective hydrogenation reaction.

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The role of La in improving the selectivity to cyclohexene of Ru catalyst for hydrogenation of benzene

Cited by 15 publications

References 31 publications

Investigation on Mn3O4 Coated Ru Nanoparticles for Partial Hydrogenation of Benzene towards Cyclohexene Production Using ZnSO4, MnSO4 and FeSO4 as Reaction Additives

Investigation on Mn3O4 Coated Ru Nanoparticles for Partial Hydrogenation of Benzene towards Cyclohexene Production Using ZnSO4, MnSO4 and FeSO4 as Reaction Additives

Selective Hydrogenation of Benzene to Cyclohexene over Monometallic Ru Catalysts: Investigation of ZnO and ZnSO4 as Reaction Additives as Well as Particle Size Effect

Selective Hydrogenation of Benzene: Progress of Understanding for the Ru-Based Catalytic System Design

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