Mechanochemical synthesis of layered hydroxy salts

Thomas, Nygil

doi:10.1016/j.materresbull.2012.06.057

Cited by 33 publications

(17 citation statements)

References 30 publications

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“…nH 2 O (where A = CH 3 COO -or MoO 4 -2 ), which resembled the formula obtained for the same system prepared by the mechanochemical method. 28 After ion exchange, molybdenum became detectable in the samples even though its amount was below the expected value. Partial exchange of acetate ions for molybdate ions may have taken place, although neither FTIR nor Raman spectroscopy detected acetate ions.…”

Section: Resultsmentioning

confidence: 94%

Intercalation of Molybdate Ions into Ni/Zn Layered Double Hydroxide Salts: Synthesis, Characterization, and Preliminary Catalytic Activity in Methyl Transesterification of Soybean Oil

Colombo¹,

Maruyama²,

Yamamoto³

2016

J. Braz. Chem. Soc.

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This study reports the synthesis and characterization of a Ni/Zn layered double hydroxide salt intercalated with acetate ions and the subsequent replacement of the acetate ions with molybdate ions via an ion exchange reaction, conducted at two different pH values. Regardless of the pH employed during the synthesis, the basal spacing in the Ni/Zn layered double hydroxide salt decreased from 13.08 Å to approximately 9.5 Å, which agreed with intercalation of hydrated molybdate anions. The non-calcined material and the material submitted to heat treatment at 250 °C (basal spacing reduced to 7.35 Å, due to dehydration) were tested as catalyst for the methyl transesterification of soybean oil. Like sodium molybdate in homogeneous media, the solid materials were active catalysts. After reaction at 120 °C for 4 h, the materials afforded high conversions at an alcohol/soybean oil molar ratio of 35:1 and preserved the structure after three consecutive uses.In conclusion, intercalation of molybdate anion into the layered double hydroxide salt proved to be an efficient alternative to support the active species and transform a soluble catalyst into a solid with application in heterogeneous catalysis.

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Section: Resultsmentioning

confidence: 94%

Intercalation of Molybdate Ions into Ni/Zn Layered Double Hydroxide Salts: Synthesis, Characterization, and Preliminary Catalytic Activity in Methyl Transesterification of Soybean Oil

Colombo¹,

Maruyama²,

Yamamoto³

2016

J. Braz. Chem. Soc.

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“…LDHs contain a mixture of trivalent and mono or divalent metal cations, 1-4 while HDSs contain only divalent metal cations. [5][6][7] The generic formula of an HDS is [(M 2+ x-1 Me 2+ x )(OH) 3(1-y) ] X n-(1+3y)/n ·zH 2 O. M and Me are divalent metal ions such Zn 2+ , Cu 2+ , Ni 2+ , or Co 2+ , 8,9 and X is an anion such as Cl -, NO 3 -, or CO 3 2-. 9,10 The latter can be replaced, through an ion exchange route, with a variety of inorganic and organic anions.…”

Section: Introductionmentioning

confidence: 99%

Hydroxy double salts loaded with bioactive ions: Synthesis, intercalation mechanisms, and functional performance

Kaassis

Guan

et al. 2016

Journal of Solid State Chemistry

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The intercalation of the anions of diclofenac (Dic), naproxen (Nap), and valproic acid (Val) into three hydroxy double salts (HDSs) has been explored in this work. Experiments were performed with [Co 1.2 Zn 3.8 (OH) 8 ](NO 3 ) 2 ·2H 2 O (CoZn-NO 3 ), [Ni 2 Zn 3 (OH) 8 ](NO 3 ) 2 ·2H 2 O (NiZn-NO 3 ) and [Zn 5 (OH) 8 ](NO 3 ) 2 ·2H 2 O (Zn-NO 3 ). It proved possible to intercalate diclofenac and naproxen into all three HDSs. In contrast, Val could be intercalated into CoZn-NO 3 but when it was reacted with Zn-NO 3 the HDS structure was destroyed, and the product comprised ZnO. Successful intercalation was verified by X-ray diffraction, IR spectroscopy, and elemental microanalysis. Molecular dynamics (MD)simulations showed the Dic and Nap ions to arrange themselves in an "X" shape in the interlayer space, forming a bilayer. Val was found to adopt a position with its aliphatic groups parallel to the HDS layer, again in a bilayer. In situ time resolved X-ray diffraction experiments revealed that intercalation of Dic and Nap into CoZn-NO 3 and Zn-NO 3 is mechanistically complex, with a number of intermediate phases observed. In contrast, the intercalation of all three guests into NiZn-NO 3 and of Val into CoZn-NO 3 are simple one step reactions proceeding directly from the starting material to product. The HDS-drug composites were found to have sustained release profiles.

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“…However, by modifying synthesis parameters detailed in the bibliography [31], the nitrate anions can isomorphically replace some hydroxyl groups, thus producing an LHS structure: nickel hydroxide nitrate with composition Ni 3 (OH) 4 NO 3 . This structure is represented in Figure 1c and is the most common LHS containing chloride, nitrate sulfate or acetate (Figure 1b) [24,32,33]. The molecular formula to represent this type of LHS is M(OH) 2-x , which can be combined in the same structure [28].…”

Section: Structure and Compositionmentioning

confidence: 99%

Functionalization of Surfaces in Layered Double Hydroxides and Hydroxide Salt Nanoparticles

Arízaga¹,

Jiménez²,

Viruete³

et al. 2016

Functionalized Nanomaterials

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Layered double hydroxides (LDH) and layered hydroxide salts (LHS) are widely studied as matrices to design new materials with applications in several areas of science and technology. Both LDH and LHS are composed of molecular layered units with surfaces fully covered by hydroxyl groups and positive-charge residues within the layers; therefore, anions in the interlayer space are needed. Even though these anions are described as interlayer species without a covalent interaction with the molecular layered units, the substitution of hydroxyl groups is also possible; in other words, the functionalization of the surface could occur. This chapter reviews results previously published related to the functionalization phenomenon in LDH and LHS, which is not considered in most of the scientific reports of new materials derived from these compounds. In this text, the use of copper probes to study electron paramagnetic resonance spectra, reinforced with infrared spectroscopy to confirm functionalization, is described. The occurrence of functionalization instead of a simple anion exchange provides a change of properties in the final nanosized material.

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Mechanochemical synthesis of layered hydroxy salts

Cited by 33 publications

References 30 publications

Intercalation of Molybdate Ions into Ni/Zn Layered Double Hydroxide Salts: Synthesis, Characterization, and Preliminary Catalytic Activity in Methyl Transesterification of Soybean Oil

Intercalation of Molybdate Ions into Ni/Zn Layered Double Hydroxide Salts: Synthesis, Characterization, and Preliminary Catalytic Activity in Methyl Transesterification of Soybean Oil

Hydroxy double salts loaded with bioactive ions: Synthesis, intercalation mechanisms, and functional performance

Functionalization of Surfaces in Layered Double Hydroxides and Hydroxide Salt Nanoparticles

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