Effect of Li on the catalytic activity of MgO for the synthesis of flavanone

Cortes-Concepcion, Jose A.; Patcas, F.; Amiridis, Michael D.

doi:10.1016/j.apcata.2010.07.013

Cited by 13 publications

(16 citation statements)

References 30 publications

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“…Alkali promoted alkaline earth metal oxides are one of the well-known solid super-base catalysts and have been widely used as catalysts for a variety of reactions such as condensation, oxidative coupling, oxidative dehydrogenation, etc. [12][13][14][15][16][17] These catalysts are prepared by different methods like co-precipitation, decomposition of carbonates, sol gel 18 and incipient wetness technique. Conventionally synthesized Li promoted on magnesium oxides requires high-temperature treatment which results in sintering and lower surface area of the resultant catalyst.…”

Section: Introductionmentioning

confidence: 99%

Green synthetic route for perfumery compound (2-methoxyethyl) benzene using Li/MgO catalyst

Tambe

Yadav

2017

J Chem Sci

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Ethers are one of the most prominent compounds among perfumery chemicals. (2-Methoxyethyl) benzene commonly known as phenyl ethyl methyl ether (PEME) is widely used in flavour and fragrance industries. Conventionally, synthesis of PEME involves the use of hazardous and polluting chemicals, which in turn affects the purity of perfumery compound. Thus, developing a green route to synthesise PEME without any hazardous chemicals is desirable. In the current work, a new process is developed for the synthesis of PEME using solid base catalysts including MgO and Li/MgO (with different loadings of lithium) and dimethyl carbonate (DMC) as a methylating agent as well as a solvent. Different kinetic parameters were studied to achieve the optimum yield of the desired product. At optimum reaction conditions i.e., 1000 rpm of speed, 1.33 × 10 −2 g/cm 3 of catalyst loading, 1:10.5 mole ratio (2-Phenyl ethanol: DMC), 180 • C, 95% conversion of 2-phenyl ethanol with 98% selectivity of PEME was achieved. A detailed kinetic model was also developed and apparent activation energy for the reaction was calculated as 11.93 kcal/mol.

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Section: Introductionmentioning

confidence: 99%

Green synthetic route for perfumery compound (2-methoxyethyl) benzene using Li/MgO catalyst

Tambe

Yadav

2017

J Chem Sci

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“…1,[9][10][11][12][13] Attempts to further enhance the basic properties as well as the catalytic activity of MgO have been made through modification of its surface structure by incorporating Group IA metals. [14][15][16][17] Although all the IA metal incorporated MgO showed enhanced basic properties compared to the bulk, the surface area of all the modified MgO is very poor, as all the Group IA metal incorporation was performed in bulk MgO or Mg(OH) 2 . Moreover, the surface area of the Group IA metal incorporation MgO is less than that of the parental bulk MgO, due to the pore blockage by the Group IA metal and the substantial promotion of sintering by alkali metals during calcination.…”

Section: Introductionmentioning

confidence: 99%

“…Moreover, the surface area of the Group IA metal incorporation MgO is less than that of the parental bulk MgO, due to the pore blockage by the Group IA metal and the substantial promotion of sintering by alkali metals during calcination. 14 The lithium incorporated MgO (Li-MgO) has been explored very well compared to other IA metals. [14][15][16] Specifically, the cesium incorporated MgO (Cs-MgO) has rarely been studied, although it is expected to give good catalytic activity.…”

Section: Introductionmentioning

confidence: 99%

“…14 The lithium incorporated MgO (Li-MgO) has been explored very well compared to other IA metals. [14][15][16] Specifically, the cesium incorporated MgO (Cs-MgO) has rarely been studied, although it is expected to give good catalytic activity. 17 Flavonoids are one of the most important classes of organic molecules and have received attention in recent research activities due to their excellent pharmacological activity towards cancer, AIDS, bacteria and inflammation.…”

Section: Introductionmentioning

confidence: 99%

“…17 Flavonoids are one of the most important classes of organic molecules and have received attention in recent research activities due to their excellent pharmacological activity towards cancer, AIDS, bacteria and inflammation. 18 MgO is the best and most widely studied solid base catalyst 6,14,19 to overcome the serious pollution problem for the synthesis of flavanone through Claisen-Schmidt condensation using a homogeneous catalyst. 20 However, despite enormous effort for selective flavanone synthesis using pure and group IA metal incorporated MgO, still selective synthesis of flavanone is challenging.…”

Section: Introductionmentioning

confidence: 99%

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Porous cesium impregnated MgO (Cs–MgO) nanoflakes with excellent catalytic activity for highly selective rapid synthesis of flavanone

et al. 2013

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Magnesium oxide (MgO) is an excellent base catalyst and its performance is well controlled by its morphology, surface area and surface structures. Here, a simple methodology for the synthesis of porous cesium impregnated MgO (Cs-MgO) nano flakes, with enhanced surface area (156 m 2 g 21 ), basic properties and improved catalytic activity for flavanone synthesis, is presented. The synthesis of Cs-MgO nano flakes is performed through impregnation of CsNO 3 on a nesquehonite [Mg(HCO 3 )OH?2H 2 O] rod, followed by calcination. During impregnation the metastable nesquehonite rod rehabilitated to hydromagnesite [4 MgCO 3 . Mg(OH) 2 ?4H 2 O] flakes. The flakes were porous, constructed by building blocks of small nanoparticles (10-25 nm) with a large number of edges and corners, step edges and step corners and numerous base sites of various strength (surface hydroxyl groups, low coordinate O 22 sites). It is observed that the amount of cesium in the MgO surface has a strong effect on its properties as well as its activity. The synthesized Cs-MgO nanoflakes showed significant improvement in the yield of flavanone through the Claisen-Schmidt condensation. A substantial increase in the reaction rate was also observed when DMF was used as a solvent without catalyst deactivation. As much as y90% conversion of 29-hydroxyacetophenone with y81% selectivity of flavanone was observed in just 15-20 min using the synthesized 0.5% Cs loaded MgO nanoflakes as a catalyst and DMF as a solvent. The improved catalytic activity of Cs-MgO as a catalyst and the promotion effect of DMF is discussed by studying the interaction of the substrate and the solvent on the catalyst surface and identification of intermediates formed on the catalyst surface under the reaction conditions using FT-IR.

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Claisen‐Schmidt Condensation using Green Catalytic Processes: A Critical Review

Yadav

Wagh

2020

ChemistrySelect

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Claisen‐Schmidt condensation have historical significance for over140 years and the scope was expanded due to the realization that chalcones so synthesized possess biological activity. The principles of green chemistry with emphasis on use of different solid catalysts with proper distribution of active centers such as acid, base, acid‐base, organo‐ were used along with solvent‐less systems. Among solid bases layered double hydroxides (LDH)/hydrotalcites are the most common. The limitations of solid bases are overcome by solid acids and superacids. A number of metal oxide supports are used. MOFs are increasingly being used. Complex organo‐catalysts are employed for getting excellent regio‐selectivity. In certain metal oxides, both acidic and basic sites co‐exist on the pore surface of catalyst which offer superior results. Synergism of solid catalysis using microwaves and ultrasound to intensify rates and selectivity is in vogue.Controlled pore structure and distribution of active catalytic centers, whether mono‐, bi‐ or tri‐functional catalysts, will give better green and smart processes. The review gives a critical analysis of the area and presents future directions for research.

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Effect of Li on the catalytic activity of MgO for the synthesis of flavanone

Cited by 13 publications

References 30 publications

Green synthetic route for perfumery compound (2-methoxyethyl) benzene using Li/MgO catalyst

Green synthetic route for perfumery compound (2-methoxyethyl) benzene using Li/MgO catalyst

Porous cesium impregnated MgO (Cs–MgO) nanoflakes with excellent catalytic activity for highly selective rapid synthesis of flavanone

Claisen‐Schmidt Condensation using Green Catalytic Processes: A Critical Review

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