- Heteropoly acid/carbon nanotube hybrid materials as efficient solid-acid catalysts
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A prototype supported solid-acid catalyst composed of a heteropoly acid (HPA) and nitrogen-functionalized carbon nanotubes (NCNT) has been developed. The chemical structure and acid strength of the HPA/NCNT hybrid have been characterized thoroughly by IR spectroscopy, X-ray photoelectron spectroscopy, TEM, and titration measurements. NCNT supports provide the HPA with an ideal hydrophobic environment, which could prevent the deactivation of the acid sites effectively in aqueous media. HPA/NCNT hybrid catalysts tend to adsorb and enrich hydrophobic substrates (ester) and release the product with high polarity (ethanol) in the aqueous phase, and this synergistic effect facilitates the catalytic process and enhances the activity of HPAs for ester hydrolysis reactions. The HPA and NCNT combine through electrostatic interactions, which ensures the relatively high stability and easy regeneration of the HPA/NCNT hybrid catalysts. The present approach provides a promising and universal strategy for the construction of hybrid catalysts based on HPA and nanocarbon with unique acidic or redox properties.
- Qi, Wei,Liu, Wei,Liu, Songyun,Zhang, Bingsen,Gu, Xianmo,Guo, Xiaoling,Su, Dangsheng
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p. 2613 - 2620
(2015/04/14)
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- An iron-containing ionic liquid as recyclable catalyst for aryl Grignard cross-coupling of alkyl halides
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The ionic liquid butylmelhylimidazolium tetrachloroferrate (bmim-FeCl 4) was found to be a very effective and completely air stable catalyst for the biphasic Grignard cross-coupling with primary and secondary alkyl halides bearing β-hydrogens. After simply decanting the product in the ethereal layer, the ionic liquid catalyst was successfully recycled four times.
- Bica, Katharina,Gaertner, Peter
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p. 733 - 735
(2007/10/03)
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- Iron-catalyzed grignard cross-coupling with alkyl halides possessing β-hydrogens
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Tris(acetylacetonato)iron(III) (Fe(acac)3) was found to be an efficient catalyst for the cross-coupling reaction between aryl Grignard reagents and alkyl halides possessing β-hydrogens. The reaction is applicable to secondary alkyl halides as well as primary ones.
- Nagano, Takashi,Hayashi, Tamio
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p. 1297 - 1299
(2007/10/03)
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- REACTION OF PHOSPHORUS OXYACID ESTERS WITH p-TOLUENESULFONIC ACID
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The reaction of primary alkyl esters of phosphorus oxyacids with p-toluenesulfonic acid (TsOH) in refluxing solvents gave the corresponding p-toluenesulfonates (TsOR).We found that the secondary alkyl esters reacted with TsOH at lower temperature (r.t.-40 deg C) to afford TsORs in good yields.It is suggested that sulfonic acids may be useful for the selective dealkylation of mixed esters.Keywords-p-toluenesulfonic acid; p-toluenesulfonate; trialkyl phosphate; trialkyl phosphite; dialkyl phenylphosphonate; transesterification; dealkylation; solvolysis.
- Nitta, Yoshihiro,Arakawa, Yasushi,Ueyama, Naoto
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p. 2710 - 2718
(2007/10/02)
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