CaAl-layered double hydroxides as active catalysts for the transesterification of glycerol to glycerol carbonate

Granados-Reyes, Judith; Salagre, Pilar; Cesteros, Yolanda

doi:10.1016/j.clay.2016.06.008

Cited by 47 publications

(18 citation statements)

References 39 publications

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“…For example, Granados‐Reyes et al. used exactly the same reaction conditions and reached the same equilibrium conversion after 3 h with a hydrotalcite catalyst . Similarly, Pan et al.…”

Section: Resultsmentioning

confidence: 99%

Hydrotalcites Promoted by NaAlO₂ as Strongly Basic Catalysts with Record Activity in Glycerol Carbonate Synthesis

et al. 2018

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A new type of highly basic catalysts is obtained by promoting Mg–Al layered double hydroxides with sodium aluminate. The Mg–Al mixed oxides obtained by the calcination of pristine hydrotalcites are poorly active in the synthesis of glycerol carbonate from glycerol and dimethyl carbonate (DCM). Pure sodium aluminate on the other hand is highly active in this reaction, but it is also highly corrosive, making its handling problematic. Remarkably, promoting hydrotalcites with low amounts of sodium aluminate is sufficient to reach high yields. At 90 °C, with 3 wt % catalyst and with a DMC/glycerol ratio of 2:1, a glycerol conversion of 92 % was achieved after 30 min over the 10 wt % NaAlO2/hydrotalcite catalyst with almost 100 % selectivity towards glycerol carbonate. The texture and the crystallinity of the catalysts were strongly affected by the addition of NaAlO2. The high activity was clearly correlated with the boost in basicity brought about by sodium aluminate promotion. Whereas pristine hydrotalcites possess only weak basic sites, the basicity of the catalysts increased drastically upon promotion with NaAlO2, both in amount and strength. Diffuse reflectance infrared spectroscopy coupled with CO2 adsorption measurements revealed the presence of surface carbonates arising from strongly basic sites. Importantly, our study demonstrates that these basic catalysts are truly heterogeneous, stable, and reusable.

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“…For example, Granados‐Reyes et al. used exactly the same reaction conditions and reached the same equilibrium conversion after 3 h with a hydrotalcite catalyst . Similarly, Pan et al.…”

Section: Resultsmentioning

confidence: 99%

Hydrotalcites Promoted by NaAlO₂ as Strongly Basic Catalysts with Record Activity in Glycerol Carbonate Synthesis

et al. 2018

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“…The peaks at 3646 cm −1 and 3456 cm −1 are related to the stretching vibrations of –OH groups in the lattice water and structural –OH groups in the CaAl-Cl-LDH [ 8 ]. The shoulder of the CaAl-Cl-LDH at 1420 cm −1 is attributed to CO 3 2− by the incorporation of CO 2 during the synthesis period [ 18 ]. Correspondingly, the newly emerged adsorption band at 1046 cm −1 is attributed to the carbonate anions of CO 3 2− intercalated in the layered Co-LDH.…”

Section: Resultsmentioning

confidence: 99%

“…There are two wide absorption bands near the regions of 650−800 cm −1 and 3000−3750 cm −1 , which are generally ascribed to the amorphous phases [ 20 ]. Either of the bands obtained at 770 cm −1 or 534 cm −1 are related to the stretching and bending vibration of Al-OH groups caused by Co 2+ adsorption [ 18 ].…”

Section: Resultsmentioning

confidence: 99%

Crystalline/Amorphous Blend Identification from Cobalt Adsorption by Layered Double Hydroxides

et al. 2018

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In this study, the adsorption behavior of CaAl-Cl layered double hydroxide (CaAl-Cl-LDH) with a controlled pH value (pH = 6) on Co(II) ions ([Co] = 8 mM) is investigated. The comprehensively accepted mechanism of cobalt adsorption on LDH is considered to be co-precipitation, and the final adsorbed products are normally crystalline Co-LDH. One unanticipated finding is that crystalline/amorphous blends are found in the X-ray diffraction (XRD) pattern of Co-adsorbed LDH. To shed light on the adsorption products and the mechanisms in the adsorption process of Co(II) in an aqueous solution by CaAl-Cl-LDH, a series of testing methods including Fourier-transform infrared spectroscopy (FT-IR), Scanning electron microscope (SEM), High-resolution transmission electron microscopy (HR-TEM), X-ray photoelectron spectroscopy (XPS), and inductively coupled plasma (ICP) are applied to clarify the interaction between cobalt and CaAl-Cl-LDH. According to the comprehensive analysis, the formation of the crystalline/amorphous blends corresponds to two adsorption mechanisms. The crystalline phases are identified as Co6Al2CO3(OH)16·4H2O, which is attributed to the co-precipitation process occurring in the interaction between Co(II) and CaAl-Cl-LDH. The formation of the amorphous phases is due to surface complexation on amorphous Al(OH)3 hydrolyzed from CaAl-Cl-LDH.

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“…The recent study of Judith Granados-Reyes et al published in 2016 [10], indicate that hydrocalumite (CaAl-LDHs) catalysts were tested in the reaction between glycerol and dimethyl carbonate to produce glycerol carbonate. After 3 hours of reaction, the glycerol conversion efficiency was as high as of 70-84 %, selectivity of glycerol carbonate was in the average range of 52-65 %, and a small amount of glycidol (7-15 %) was formed.…”

Section: Introductionmentioning

confidence: 99%

SYNTHESIS GLYCEROL CARBONATE FROM GLYCEROL AND URE USED SOLID ACID-BASE CATALYSTS BASED ON Zn-Al

Phuong¹

2018

JST

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In this study, we successfully synthesized Zn-Sn and Al-Sn catalysts by the combination of co-precipitation and hydrothermal methods. These catalysts were prepared by hydrothermal method using ZnCl 2 , SnCl 4 and AlCl 3 precursors. Structure and physical properties of catalysts were characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM). The products of glycerol conversion product was also tested by gas chromatography. The catalytic activity of Zn-Sn and Al-Sn depends on reaction conditions (temperature and catalysts). The main product formed after the carbonylation reaction was glycerol carbonate. The selectivity of the main product was highest when using the Zn-Sn catalyst 5 % at a 145 °C during 5 hours, that the yield was 77.0 %, the conversion degree was 88.5 % and the selectivity was 86.9 %. For Al-Sn catalyst under the same reaction conditions, the efficiency was 61.3 % and the product selectivity achieved up to 74.1 %.

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CaAl-layered double hydroxides as active catalysts for the transesterification of glycerol to glycerol carbonate

Cited by 47 publications

References 39 publications

Hydrotalcites Promoted by NaAlO₂ as Strongly Basic Catalysts with Record Activity in Glycerol Carbonate Synthesis

Hydrotalcites Promoted by NaAlO₂ as Strongly Basic Catalysts with Record Activity in Glycerol Carbonate Synthesis

Crystalline/Amorphous Blend Identification from Cobalt Adsorption by Layered Double Hydroxides

SYNTHESIS GLYCEROL CARBONATE FROM GLYCEROL AND URE USED SOLID ACID-BASE CATALYSTS BASED ON Zn-Al

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CaAl-layered double hydroxides as active catalysts for the transesterification of glycerol to glycerol carbonate

Cited by 47 publications

References 39 publications

Hydrotalcites Promoted by NaAlO2 as Strongly Basic Catalysts with Record Activity in Glycerol Carbonate Synthesis

Hydrotalcites Promoted by NaAlO2 as Strongly Basic Catalysts with Record Activity in Glycerol Carbonate Synthesis

Crystalline/Amorphous Blend Identification from Cobalt Adsorption by Layered Double Hydroxides

SYNTHESIS GLYCEROL CARBONATE FROM GLYCEROL AND URE USED SOLID ACID-BASE CATALYSTS BASED ON Zn-Al

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Hydrotalcites Promoted by NaAlO₂ as Strongly Basic Catalysts with Record Activity in Glycerol Carbonate Synthesis

Hydrotalcites Promoted by NaAlO₂ as Strongly Basic Catalysts with Record Activity in Glycerol Carbonate Synthesis