Hydrotalcites supported on carbon nanofibers as solid base catalysts for the synthesis of MIBK

Winter, Ferry; Koot, Vincent; Dillen, A.J. van; Geus, J.W.; Jong, Krijn P. de

doi:10.1016/j.jcat.2005.09.020

Cited by 72 publications

(54 citation statements)

References 49 publications

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“…Various methods have been explored to overcome these problems, such as the combination of LDH with carbon nanofibers [14] and carbon nanotubes [15][16][17][18][19][20], as previously studied in our group [21]. Among the nanocarbons, the 2D geometry of graphene oxide (GO) is obviously compatible with the layered structure of LDHs and there is also a charge compatibility between the positively charged LDH and negatively charged GO.…”

Section: Introductionmentioning

confidence: 99%

Graphene-oxide-supported CuAl and CoAl layered double hydroxides as enhanced catalysts for carbon-carbon coupling via Ullmann reaction

Ahmed

Menzel

Wang

et al. 2017

Journal of Solid State Chemistry

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Two efficient catalyst based on CuAl and CoAl layered double hydroxides (LDHs) supported on graphene oxide (GO) for the carbon-carbon coupling (Classic Ullmann Homocoupling Reaction) are reported. The pure and hybrid materials were synthesised by direct precipitation of the LDH nanoparticles onto GO, followed by a chemical, structural and physical characterization by electron microscopy, X-ray diffraction (XRD), thermogravimetric analysis (TGA), surface area measurements, X-ray photoelectron spectroscopy (XPS) and temperature programmed reduction (TPR). The GO-supported and unsupported CuAl-LDH and CoAl-LDH hybrids were tested over the Classic Ullman Homocoupling Reaction of iodobenzene. In the current study CuAl-and CoAl-LDHs have shown excellent yields (91% and 98%, respectively) at very short reaction times (25 min). GO provides a light-weight, charge complementary and two-dimensional material that interacts effectively with the 2D LDHs, in turn enhancing the stability of LDH. As a result, the recyclability of the heterogeneous catalyst systems is greatly enhanced. After 5 re-use cycles, the catalytic activity of the LDH/GO hybrid is up to 2 times higher than for the unsupported LDH.

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Section: Introductionmentioning

confidence: 99%

Graphene-oxide-supported CuAl and CoAl layered double hydroxides as enhanced catalysts for carbon-carbon coupling via Ullmann reaction

Ahmed

Menzel

Wang

et al. 2017

Journal of Solid State Chemistry

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“…As a catalyst support, CHT can be used for nitrous oxide decomposition [28], MIBK synthesis [29], etc.…”

Section: Introductionmentioning

confidence: 99%

Role of the Mg/Al atomic ratio in hydrotalcite-supported Pd/Sn catalysts for nitrate adsorption and hydrogenation reduction

Wan¹,

Liu²,

Zhao³

et al. 2009

Journal of Colloid and Interface Science

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Hydrotalcite-supported Pd/Sn catalysts with different Mg/Al atomic ratios (2, 3, 4, and 5) for nitrate adsorption and hydrogenation reduction were successfully synthesized by a coprecipitation method. The results showed that different atomic ratios of Mg/Al resulted in different interlayer spacings and zetapotentials of the catalysts, which thus influenced its adsorption capacity. With the increase of Mg/Al atomic ratio, the interlayer spacing rose and zeta-potential decreased. The adsorption properties of the catalysts were mainly affected by interlayer spacing when Mg/Al atomic ratios increased from 2 to 4. However, when Mg/Al atomic ratios further increased from 4 to 5, there was a negative impact on the adsorption properties of zeta-potential. Also, the adsorption capacity of the catalysts for nitrate followed the order: Mg/Al = 2 < Mg/Al = 3 < Mg/Al = 5 < Mg/Al = 4. In the catalytic reduction process, the adsorbed nitrates were further reduced to nitrites that remained in the same position in catalysts, but some of superabundant nitrites were released into water as primary and unstable products. The concentration of released nitrites was in the reverse order of the adsorption capacity. The catalytic selectivity and activity of the catalysts for nitrate reduction had the same sequence as its adsorption capacity.

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“…Other investigations reported in literature showed that the actual active basic sites in activated HTs are situated at the edges of the platelets and that the number of these sites can be varied by changing the lateral platelet size [38,40,41,45,46]. A linear correlation between the number of active sites and the activity in the condensation of acetone at 273 K was found [38,40,46].…”

Section: Condensation and Dehydration Over Activated Htsmentioning

confidence: 70%

“…A linear correlation between the number of active sites and the activity in the condensation of acetone at 273 K was found [38,40,46]. We investigated whether a similar structure-activity relationship could be derived for the dehydration reaction as the dehydration reaction is also catalyzed by basic sites [1].…”

Section: Condensation and Dehydration Over Activated Htsmentioning

confidence: 99%

A hydrotalcite-based catalyst system for the single-stage liquid-phase synthesis of MIBK

Winter

Wolters

Dillen

et al. 2006

Applied Catalysis A: General

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A comparative study was performed between Pd supported on activated hydrotalcites bi-functional catalysts and physical mixtures of activated hydrotalcites with Pd supported on carbon nanofibers for the single-stage liquid-phase synthesis of methyl isobutyl ketone from acetone and H 2 . Since it was found earlier that the dehydration reaction of diacetone alcohol over activated hydrotalcites is the rate-determining step in this process, Mg-Al hydrotalcites were investigated in the condensation of acetone to diacetone alcohol and its dehydration to mesityl oxide to enhance the activity. A correlation between the number of active base sites, as determined by volumetric CO 2 adsorption measurements at low pressures, and the activity in the dehydration reaction could be derived. A dependency on the Pd-loading (0-1 wt%) of Pd supported on activated hydrotalcites catalysts was found in the single-stage synthesis of methyl isobutyl ketone, whereas no such an effect was found when using physical mixtures of activated hydrotalcites with Pd on carbon nanofibers. Results from TEM, CO 2 chemisorption and N 2 physisorption as well as catalytic experiments in the hydrogenation of mesityl oxide and of cyclohexene indicate that this dependency is largely accounted for by entrapment of Pd particles in the agglomerates of the irregular stacks of hydrotalcite platelets, making these sites inaccessible for the reactants. #

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Hydrotalcites supported on carbon nanofibers as solid base catalysts for the synthesis of MIBK

Cited by 72 publications

References 49 publications

Graphene-oxide-supported CuAl and CoAl layered double hydroxides as enhanced catalysts for carbon-carbon coupling via Ullmann reaction

Graphene-oxide-supported CuAl and CoAl layered double hydroxides as enhanced catalysts for carbon-carbon coupling via Ullmann reaction

Role of the Mg/Al atomic ratio in hydrotalcite-supported Pd/Sn catalysts for nitrate adsorption and hydrogenation reduction

A hydrotalcite-based catalyst system for the single-stage liquid-phase synthesis of MIBK

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