The metal ion modified ionic liquids promoted free-solvent alkylations of α-methylnaphthalene with long-chain olefins

Zhao, Zhongkui; Yuan, Bing; Qiao, Wenxiao; Li, Zongshi; Wang, Guiru; Liu, Cheng

doi:10.1016/j.molcata.2005.03.013

Cited by 20 publications

(5 citation statements)

References 29 publications

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“…Our synthesis strategy includes three steps: (1) synthesizing PImM; (2) grinding the mixture of nanocarbons and PImM to form plasticine-like precursors; and (3) pyrolysis to achieve nanocarbon-embedded network monolith. As illustrated in Figure b, to take ND as an example, first, based on references, , PImM was synthesized by polymerization of imidazole with dichloromethane in an autoclave at 1.5 MPa and 95 °C for different reaction times (5, 6, 8, and 10 h, defined as PImM- x , x = 5, 6, 8, 10). The as-synthesized PImM features a brown solid at room temperature with different viscosities (Figures S1–S3), implying the successful synthesis of poly(imidazolium-methylene) cations rather than 1,1′-methylene bis(imidazole) (needle-like crystals) .…”

Section: Resultsmentioning

confidence: 99%

Poly(imidazolium-methylene)-Assisted Grinding Strategy to Prepare Nanocarbon-Embedded Network Monoliths for Carbocatalysis

Zhou

Guo

et al. 2020

ACS Catal.

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Nanocarbons as alternatives to metal-based catalysts have attracted great interest in heterogeneous catalysis. However, the powder form of nanocarbons limits their industrial applications because of the large pressure drop in a fixed-bed reactor and the big difficulties in handling loose powder in a fluidized-bed reactor. To address these issues, herein, we report a general poly(imidazolium-methylene)-assisted grinding strategy for synthesizing mechanically robust nanocarbon-embedded network monoliths by grinding a mixture composed of nanocarbons and the as-formed poly(imidazolium-methylene) chloride (PImM) with a subsequent pyrolysis process. The as-prepared nanocarbon-based network monoliths feature nanocarbons to be well-dispersed within a N-doped carbon (NC) network. The monolith is adequately hard and high density and can be cracked and sieved into granule nanocarbon catalysts. Taking nanodiamonds (NDs) as an example, in the grinding procedure, PImM can penetrate into ND aggregates to disperse NDs and can adhere the deagglomerated NDs because there is a strong interaction between NDs and PImM through strong cation−π interactions, π–π interactions, and electrostatic interactions since many nanocarbons including NDs have negative charges on their surface. The designed PImM plays three roles in the preparation of ND-embedded network monolith including the adhering agent, isolating agent, and a precursor of the NC network. The resulting granule ND@NC carbocatalyst from its corresponding ND@NC network monolith shows 6.39 mmol g–1 h–1 of steady-state styrene rate (9.26 and 2.24 times higher compared to that of NC and ND, respectively) with 99.0% of styrene selectivity for ethylbenzene direct dehydrogenation (EDH) to styrene, a commercially important reaction. The granule ND@NC carbocatalyst also shows high catalytic stability for EDH reaction. The strategy has been extended to carbon nanofiber-embedded monoliths. This work not only creates a granule carbocatalyst for styrene production via EDH reaction but also paves an avenue to overcome the bottleneck problems regarding the applications of the powders of diverse nanocarbons in heterogeneous catalysis.

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Section: Resultsmentioning

confidence: 99%

Poly(imidazolium-methylene)-Assisted Grinding Strategy to Prepare Nanocarbon-Embedded Network Monoliths for Carbocatalysis

Zhou

Guo

et al. 2020

ACS Catal.

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“…Moreover, at the compositions where neutrality could be expected based on stoichiometry (w MCl n = 0.50 for M = Cu, Fe, Al, and w ZnCl 2 = 0.33), a free pyridine signal was observed for each sample, indicative of the lack of acidity. The same methodology as been employed using acetonitrile for other ionic liquids 162 including cholinium chlorozincates(II). 163 Xin et al 164 demonstrated that, unsurprisingly, replacing chlorides coordinating to the metal centre with bromides or iodides enhances Lewis acidity of the chlorometallate ionic liquids, which for w Although these measurements are simple, the molecular probes (pyridine, acetonitrile etc.)…”

Section: Measurement Of Lewis Aciditymentioning

confidence: 99%

Halometallate ionic liquids – revisited

Estager¹,

2014

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Ionic liquids with chlorometallate anions may not have been the first ionic liquids, however, it was their development that lead to the recognition that ionic liquids are a distinct, and useful, class of (functional) materials. While much of the phenomenal interest and attention over the past two decades has focussed on 'air and water stable' ionic liquids, research and application of chlorometallate systems has continued unabated albeit largely out of the main spotlight. The defining characteristic of chlorometallates is the presence of complex anionic equilibria, which depend both on the type and on the concentration of metal present, and leads directly to their characteristic and individual properties. Here, we review the experimental techniques that can be applied to study and characterise the anion speciation in these ionic liquids and, using recent examples, illustrate how their applications base is evolving beyond traditional applications in Lewis acidic catalysis and electrochemistry through to uses as soft and component materials, in the ionothermal synthesis of semiconductors, gas storage systems and key components in the development of biomass processing.

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“…The change in the IR frequencies of the probe molecule was correlated to the Lewis acidity of the solvent. Zhao et al 24 used ethanenitrile as internal probe for ionic liquids with chloroaluminate(III), chloroferrate(III) and chlorocuprate(II) anions. This methodology has been employed subsequently for mixtures of cholinium chloride and ZnCl 2 .…”

Section: Introductionmentioning

confidence: 99%

Chlorometallate(iii) ionic liquids as Lewis acidic catalysts – a quantitative study of acceptor properties

et al. 2010

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The Gutmann Acceptor Number (AN), which is a quantitative measure of Lewis acidity, has been estimated using the (31)P NMR chemical shift of a probe molecule, triethylphosphine oxide, for a range of chlorometallate(III) ionic liquids, based on Group 13 metals (aluminium(III), gallium(III) and indium(III)) and the 1-octyl-3-methylimidazolium cation, at different compositions. The results were interpreted in terms of extant speciation studies of chlorometallate(III) ionic liquids, and compared with a range of standard molecular solvents and acids. The value of these data were illustrated in terms of the selection of appropriate ionic liquids for specific applications.

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The metal ion modified ionic liquids promoted free-solvent alkylations of α-methylnaphthalene with long-chain olefins

Cited by 20 publications

References 29 publications

Poly(imidazolium-methylene)-Assisted Grinding Strategy to Prepare Nanocarbon-Embedded Network Monoliths for Carbocatalysis

Poly(imidazolium-methylene)-Assisted Grinding Strategy to Prepare Nanocarbon-Embedded Network Monoliths for Carbocatalysis

Halometallate ionic liquids – revisited

Chlorometallate(iii) ionic liquids as Lewis acidic catalysts – a quantitative study of acceptor properties

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