“…Although decarbonized water was used, the experiments on hydration and anion-exchanges were in open air; therefore, some contamination of samples with carbonate was possible. In the FTIR spectra of the phosphate-intercalated LDHs, the intense bands situated at ~1060 cm −1 which could be assigned to vibrations in phosphate tetrahedron 14 are clearly seen.Figure 4FTIR spectra of LDHs obtained via hydration and anion exchanges at the conditions indicated in the plot labels.…”
Section: Resultsmentioning
confidence: 99%
“…Different layer charge density conditioned by the cations ratio and the natural flexibility of the crystal structure allows formation of LDHs intercalated with a great variety of inorganic anions [ref. 3 and the references therein], among them the most occurred are Cl − 8,9 , OH − 10 , CO 3 2− 11 , PO 4 3− 12–14 , and organic anions [ref. 3 and the references therein 15 ].…”
Single-phase magnesium-aluminium layered double hydroxide (LDH) intercalated with dihydrogen phosphate was successfully produced by hydration of nanopowder of the respective mixed metal oxide (MMO) obtained using sol-gel based method followed by a two-step anion exchange hydroxide-to-chloride and chloride-to-phosphate. The MMO with the metal cation ratio of Mg/Al = 2:1 was prepared using the aqueous sol-gel method. Processes of the parent Mg
2
Al-OH LDH formation and the successive anion-exchanges, ОН
−
→ Cl
−
and Cl
−
→ H
2
PO
4
−
, were considerably accelerated via the application of high-power (1.5 kW) ultrasound. The crystalline phases formed at all stages of the Mg
2
Al-H
2
PO
4
LDH production were characterized using X-ray diffraction, scanning electron microscopy, scanning transmission electron microscopy, inductive coupled plasma optical emission spectroscopy, Fourier transform infrared spectroscopy, and thermogravimetric analysis. Based on the data of chemical analysis and the XRD data, the type of the intercalated phosphate anion was determined and the arrangement of this anion in the interlayer was modelled.
“…Although decarbonized water was used, the experiments on hydration and anion-exchanges were in open air; therefore, some contamination of samples with carbonate was possible. In the FTIR spectra of the phosphate-intercalated LDHs, the intense bands situated at ~1060 cm −1 which could be assigned to vibrations in phosphate tetrahedron 14 are clearly seen.Figure 4FTIR spectra of LDHs obtained via hydration and anion exchanges at the conditions indicated in the plot labels.…”
Section: Resultsmentioning
confidence: 99%
“…Different layer charge density conditioned by the cations ratio and the natural flexibility of the crystal structure allows formation of LDHs intercalated with a great variety of inorganic anions [ref. 3 and the references therein], among them the most occurred are Cl − 8,9 , OH − 10 , CO 3 2− 11 , PO 4 3− 12–14 , and organic anions [ref. 3 and the references therein 15 ].…”
Single-phase magnesium-aluminium layered double hydroxide (LDH) intercalated with dihydrogen phosphate was successfully produced by hydration of nanopowder of the respective mixed metal oxide (MMO) obtained using sol-gel based method followed by a two-step anion exchange hydroxide-to-chloride and chloride-to-phosphate. The MMO with the metal cation ratio of Mg/Al = 2:1 was prepared using the aqueous sol-gel method. Processes of the parent Mg
2
Al-OH LDH formation and the successive anion-exchanges, ОН
−
→ Cl
−
and Cl
−
→ H
2
PO
4
−
, were considerably accelerated via the application of high-power (1.5 kW) ultrasound. The crystalline phases formed at all stages of the Mg
2
Al-H
2
PO
4
LDH production were characterized using X-ray diffraction, scanning electron microscopy, scanning transmission electron microscopy, inductive coupled plasma optical emission spectroscopy, Fourier transform infrared spectroscopy, and thermogravimetric analysis. Based on the data of chemical analysis and the XRD data, the type of the intercalated phosphate anion was determined and the arrangement of this anion in the interlayer was modelled.
“…The further development of Y 2 O 3 may be promising and it is important to make clear the difference between Y 2 O 3 and CeO 2 catalysts. It has been also reported that DMC synthesis is catalyzed by phosphoric acid intercalated Mg-Al hydrotalcitelike compounds (Ghorbel et al, 2015), although the catalytic activity is not so high (Table 2, Entry 9).…”
Reaction of CO 2 with alcohols to organic carbonates is one of non-reductive CO 2 conversion methods. The catalysts are needed for this reaction, at the same time, effective H 2 O removal methods are also needed because the yield of organic carbonates is strongly limited by the equilibrium. The development of heterogeneous catalysts for the synthesis of dimethyl carbonate from CO 2 and methanol, which is a model and typical reaction, is described. This is because heterogeneous catalysts are more suitable to the practical process than homogeneous catalysts from the viewpoint of the separation of catalysts from the products and the reusability of the catalysts. One of the reported heterogeneous catalysts is CeO 2 , and it has been also reported that the combination of dimethyl carbonate synthesis from CO 2 and methanol with the hydration of nitriles such as 2-cyanopyridine, where both reactions are catalyzed by CeO 2 , enabled high yield of the carbonate. In addition, the combination of CeO 2 catalyst + nitriles can be applied to the synthesis of a variety of linear-, cyclic (five-and six-membered ring)-, and poly-carbonates from CO 2 and corresponding alcohols.
“…These differences in microstructure might be the reason of the more efficient catalytic performance. 1 Continuous tubular fixed bed reactor; 2 ZIF-8, TEG, KHNTs, MS, AC, MWCNTs are zeolitic imidazolate framework-8, thermally expanded graphite, K treated halloystite nanotubes, molecular sieves, activated carbon, multi-walled carbon nanotubes; 3 The reaction mixture was exposed to ultra violent (UV) radiation.…”
“…For example, it can be used for polymer synthesis, as a solvent, and a fuel additive. A number of publications about dimethyl carbonate (DMC) synthesis appeared recently [1][2][3][4][5]. Several synthetic routes affording DMC were reported; for example, methanolysis of phosgene [6], oxidative carbonylation of methanol [7], transesterification of ethylene carbonate [8] or urea [9], electrochemical synthesis [10], direct DMC synthesis from carbon dioxide and methanol [11].…”
Conversion of carbon dioxide into useful chemicals is a valuable task. One way to perform it is to transform CO 2 into dimethyl carbonate (DMC) by a reaction with methanol. Catalyst exerts significant impact on this process. During this work, Cu-Ni@VSiO bimetallic catalysts were successfully synthesized by traditional solution and novel sulfuration methods. The catalytic materials were characterized by several analytical techniques and were tested in a continuous fixed-bed reactor under different reaction conditions to promote DMC synthesis from CO 2 and methanol in the absence of dehydrating agents. The effects of reaction temperature, pressure, space velocity, metal loading, and bulk density on the catalytic performance were investigated in detail. It was found that the activity of Cu-Ni@VSiO catalyst with the support obtained by the novel sulfuration method is about three times higher when compared to that of the catalyst with the support that is synthesized by the traditional solution method. This result may stem from the difference in microstructure of the studied catalytic materials.
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