Preparation of active MgO by short-time thermal decomposition of Mg(OH)2

Kitagawa, Michiko; Misu, Sayaka; Ichikawa, Jun; Matsuhashi, Hiromi

doi:10.1007/s11164-015-1971-z

Cited by 19 publications

(9 citation statements)

References 8 publications

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“…The higher calcination temperature would generate further stronger basic sites (Figure 1a), due to exposure of more surface defects. 50 Similarly, the selectivity for OPP using the Pt/MgO-900 catalyst was 6% higher than in the case of Pt/ MgO (Table 1). As a consequence, the amount and strength of basic sites were crucial for the formation of OPP.…”

Section: ■ Results and Discussionmentioning

confidence: 91%

“…The basic strength of MgO was changed to verify the effect of basic sites on the production of OPP by changing the calcination temperature of MgO. The higher calcination temperature would generate further stronger basic sites (Figure a), due to exposure of more surface defects . Similarly, the selectivity for OPP using the Pt/MgO-900 catalyst was 6% higher than in the case of Pt/MgO (Table ).…”

Section: Resultsmentioning

confidence: 99%

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Selective Hydrogenolysis of Dibenzofuran over Highly Efficient Pt/MgO Catalysts to o-Phenylphenol

Zhang

Wang

et al. 2018

Org. Process Res. Dev.

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Direct selective hydrogenolysis of dibenzofuran (DBF) derived from coal and shale oil to a value-added chemical, ortho-phenylphenol (OPP), with high selectivity (80%) and yield (48%) has been achieved over Pt/MgO at 400 °C and 1.0 MPa by controlling the C–O bond cleavage as well as minimizing the extent of hydrogenation of aromatic rings. Meanwhile, Pt/SiO2, Pt/Al2O3, and Pt/MgO/Al2O3 catalysts were used for the DBF hydrogenolysis and showed lower selectivity for OPP. The influence of reaction parameters has been studied to unveil the optimal reaction conditions. And the phenomenon of OPP dehydrogenation is found over various catalysts for the hydrogenation reaction of OPP. Extensive reactions and catalyst characterizations demonstrated that the OPP selectivity and the dehydrogenation of OPP to DBF follows the order of supports basicity: MgO-900 > MgO > SiO2 > MgO/Al2O3 > Al2O3, which shows that the acid–base properties of supports impact the adsorption and desorption behaviors of DBF and OPP, and results in the disparity of OPP selectivity and the dehydrogenation of OPP. Finally, a plausible reaction pathway and mechanistic understanding are proposed.

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Section: ■ Results and Discussionmentioning

confidence: 91%

Section: Resultsmentioning

confidence: 99%

Selective Hydrogenolysis of Dibenzofuran over Highly Efficient Pt/MgO Catalysts to o-Phenylphenol

Zhang

Wang

et al. 2018

Org. Process Res. Dev.

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“…Magnesium hydroxide (Mg(OH) 2 ) and hydrated magnesium carbonate ((MgCO 3 ) 4 ·Mg(OH) 2 ·5H 2 O) of reagent grade were purchased from Nacalai Tesque, Inc. (Japan) and Kishida Chemical Co. Ltd. (Japan), respectively. Based on the report by Matsuhashi et al, magnesium oxide (MgO) was prepared by calcination of Mg(OH) 2 at 600 °C for 1 h in an electric furnace. These chemicals (purities > 99.99%) were used without further purification.…”

Section: Methodsmentioning

confidence: 99%

Investigation on the Mechanisms of Mg(OH)₂ Dehydration and MgO Hydration by Near-Infrared Spectroscopy

et al. 2021

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The mechanism for the dehydration of Mg(OH)2 and hydration of MgO was investigated by near-infrared (NIR) spectroscopy. Mg(OH)2 showed three absorption bands in the NIR region at 7339, 7306, and 7157 cm–1, due to the different hydroxyl groups (7339 cm–1: OH(e) and OH(c) located on the edge and corner of the Mg(OH)2 sheet, 7306 cm–1: OH(t) located on the terrace of Mg(OH)2 sheet, 7157 cm–1: OH(i) located on the interlayer of Mg(OH)2 sheets). During the phase transition from Mg(OH)2 to MgO at approximately 400 °C, the interlayer OH(i) of Mg(OH)2 disappeared by a dehydration reaction and the OH(t) on the (001) plane of Mg(OH)2 was converted to the hydrogen-bonded hydroxyl groups on the (111) plane of MgO (7309 cm–1). Furthermore, when MgO was in contact with water vapor at 85 and 50 °C (RH 85%), the isolated hydroxyl groups of the MgO surface (7360 cm–1) were easily hydrated to form hydrogen-bonded ones (7309 cm–1). When a monolayer Mg(OH)2 sheet was formed on the MgO surface, OH(e), OH(c), and OH(t) were observed at 7345 and 7309 cm–1. As the hydration reaction proceeded, the intermediate state like stacking of several Mg(OH)2 sheets, which are related to the decrease in the OH(t) and the spontaneous increase in the interlayer OH(i), was experimentally confirmed.

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“…The base catalytic activity decreased with higher calcination temperature for all catalysts. The reaction rate calculated by applying the first order reaction equation was 0.89 mol g -1 h -1 for SAH1 treated at 673 K, almost equal to 0.91 mol g -1 h -1 of BaO _ Al2O3 prepared from Ba(OH)2 H2O and Al(OCH(CH3)2)3 using solid-liquid interface reaction 30) , and higher than 0.48 mol g -1 h -1 of MgO prepared from Mg(OH)2 by a conventional method 22) . The turnover frequency normalized by the number of atoms of alkaline earth elements contained was 138, 186, and 19 h -1 , for SAH1, BaO _ Al2O3, and MgO, respectively.…”

Section: Retro-aldol Reactionmentioning

confidence: 76%

Synthesis of SrO–Al<sub>2</sub>O<sub>3</sub> Solid Base Catalysts from Strontium Hydroxide and Aluminum Alkoxide by a Solid-liquid Interface Reaction

Matsuhashi

Iwamoto

Sasaki

et al. 2021

J. Jpn. Petrol. Inst.

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Preparation of active MgO by short-time thermal decomposition of Mg(OH)2

Cited by 19 publications

References 8 publications

Selective Hydrogenolysis of Dibenzofuran over Highly Efficient Pt/MgO Catalysts to o-Phenylphenol

Selective Hydrogenolysis of Dibenzofuran over Highly Efficient Pt/MgO Catalysts to o-Phenylphenol

Investigation on the Mechanisms of Mg(OH)₂ Dehydration and MgO Hydration by Near-Infrared Spectroscopy

Synthesis of SrO–Al<sub>2</sub>O<sub>3</sub> Solid Base Catalysts from Strontium Hydroxide and Aluminum Alkoxide by a Solid-liquid Interface Reaction

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Preparation of active MgO by short-time thermal decomposition of Mg(OH)2

Cited by 19 publications

References 8 publications

Selective Hydrogenolysis of Dibenzofuran over Highly Efficient Pt/MgO Catalysts to o-Phenylphenol

Selective Hydrogenolysis of Dibenzofuran over Highly Efficient Pt/MgO Catalysts to o-Phenylphenol

Investigation on the Mechanisms of Mg(OH)2 Dehydration and MgO Hydration by Near-Infrared Spectroscopy

Synthesis of SrO–Al<sub>2</sub>O<sub>3</sub> Solid Base Catalysts from Strontium Hydroxide and Aluminum Alkoxide by a Solid-liquid Interface Reaction

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Investigation on the Mechanisms of Mg(OH)₂ Dehydration and MgO Hydration by Near-Infrared Spectroscopy