Umberto Costantino

Università degli Studi di Perugia | UNIPG · Department of Chemistry

The invention concerns a system for biocompatible drug release comprising: (i) a polymer matrix; (ii) an inorganic component located inside said matrix and characterized by a lamellar structure with a net positive or negative charge able to intercalate (iii) a pharmacologically active principle into said lamellar structure, by establishing an ionic...

A layered double hydroxide (LDH) obtained by the urea method, having an empirical formula [Zn0.61Al0.39(OH)2](CO3)0.195·0.50H2O, has been converted into the corresponding chloride form [Zn0.61Al0.39(OH)2]Cl0.39·0.47H2O by making the solid come into contact with a suitable HCl solution. The intercalation of the other halide anions (X(-) = F(-), Br(-...

Layered double hydroxides (LDH), also referred as hydrotalcite like compounds (HTlc), constitute a large group of natural and synthetic minerals whose physico-chemical properties have strong analogies with clay minerals and more particularly with cationic clay minerals. In the first part, LDH are described in terms of natural and synthetic chemical...

After a brief recall of layered double hydroxides (LDH) features to underline the reasons of the present exponential growth of the number of patents and papers dealing with application in several sometime unexpected fields, the chapter will deal only with selected applications, namely, (1) environmental protection and agricultural aids; (2) heterog...

The chapter reports a wide survey on the synthesis, structure and properties of many zirconium phosphates and phosphonates, with a special attention devoted to the work made in the Laboratory of Inorganic Chemistry of University of Perugia in the last thirty years. Zirconium phosphates and phosphonates with alpha or gamma type layered structure are...

Hydrotalcite-like compounds (HTlc), belonging to the large class of Layered Double Hydroxides (LDH), have excited wide interest owing to the incredible number of their potential and achieved applications in physical, chemical and bio-chemical fields. This perspective review deals with recent advances in the application of physical-chemical techniqu...

This review treats with recent patents and related literature, mainly from the Authors laboratories, on biomedical and food packaging applications of nano-composites constituted of biodegradable polymers filled with micro or nano crystals of organically modified Layered Double Hydroxides of Hydrotalcite type. After a brief outline of the chemical a...

Molecular iodine was intercalated from nonaqueous solution into microsized ZnAl-layered double hydroxide (LDH) in the iodide form, generating the I(3)(-)/I(-) redox couple into the interlayer region. Chloroform, ethanol, acetonitrile, or diethyl ether were used as solvents to dissolve the molecular iodine. The intercalation compounds were character...

A new easy method for the preparation of polymeric nanocomposites supporting metal nanoparticles is presented. The method concerns the use of a layered inorganic ion exchanger converted in the proper metallic form and exfoliated to act as filler of organic polymers with twofold aim of obtaining a composite (or nanocomposite) and to have metal ions...

A nanostructured hydrotalcite-like compound of formula [Zn0.72Al0.28(OH)2] Br0.28·0.69 H2O has been used as inorganic layered host of the anionic form of diclofenac (DIK), a Non Steroidal Antiinflammatory Drug. The obtained intercalation compound has been characterized by chemical analysis, X-ray powder diffraction pattern, thermogravimetrical anal...

This chapter deals with the preparative methods, structural aspects and chemical-physical characteristics of hydrotalcite-like compounds (HTlc), an emerging class of layered solids with anion exchange and intercalation properties. Biocompatible HTlc can be modified with molecular anions having pharmaceutical, antimicrobial or antioxidant activity t...

Epoxy resin nanocomposites containing home–made hydrotalcites (HTlc) have been prepared and their properties have been studied and compared with those of montmorillonite (MMT)-type layered silicates-based nanocomposites. Nanofiller dispersion in the polymer matrix has been evaluated by transmission (TEM) electron microscopy and wide angle X-ray dif...

The presence of H3PO3 in the synthesis of zirconium diphosphonates in dimethylsulfoxide, other than the expected dilution of the pillars, which in turn gives rise to a certain degree of microporosity, may also induce the formation of a high percentag. of mesopores. E.g., compounds with high surface area(300–500 m2 /g) of which 60–70% is due to meso...

Commercial clays Cloisites®Na+, 30B and 20A were labelled with the fluorescent dye Rhodamine B and used as fillers of polypropylene in order to prepare composites to be studied with confocal fluorescence microscopy. The dye uptake by clays was monitored by X-ray powder diffraction and spectroscopic analyses and clear evidences of intercalated dye i...

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Monophasic ZnAl hydrotalcite-like layered hydroxycarbonate has been prepared by the urea precipitation method. This material has been characterized by Rietveld refinement of the XRPD pattern, DTA-TG and skeletal IR. ZnAl mixed oxides have been prepared by calcinations of this precursor. According to XRPD, after calcinations at 450°C this material i...

The aza-Diels–Alder reaction between benzaldimines 1 and Danishefsky's diene in solvent-free conditions is reported for the first time. The reaction occurs rapidly at 30°C and is catalyzed by porous α-zirconium hydrogen phosphate (p-αZrP) in the presence of sodium dodecyl sulfate (SDS). The yields were excellent. The recycling of the catalyst has a...

The urea hydrolysis method allowed to prepare well-crystallized Ni–Co–Zn–Al Layered Double Hydroxides to be used as precursors of mixed oxide catalysts for the Ethanol Steam Reforming (ESR) reaction. The calcination of the layered precursors gives rise to high surface area mixed oxides, being actually a mixture of a rock salt phase (NiO), a wurtzit...

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Intercalation compounds of ZnAl-Layered Double Hydroxide (LDH) with Benzoate (Bz), 2,4-dichlorobenzoate (BzDC), para-hydroxybenzoate (p-BzOH) and ortho-hydroxybenzoate (o-BzOH) anions, have been prepared via anion exchange procedure. The obtained inorganic–organic nano-hybrids were incorporated by High Energy Ball Milling (HEBM) into polycaprolacto...

Zirconium Sulfophenyl Phosphonate Zr(O3PCH3)(1.2)(O3PC6- InSO3H)(0.8) was found to be an efficient heterogeneous catalyst for the tetrahydropyranylation of alcohols and phenols.

A series of well crystallized Ni-Co-Zn-Al LDHs materials has been prepared by the urea hydrolysis method as precursors of mixed oxide catalysts for the Ethanol Steam Reforming (ESR) reaction. The calcination of the layered precursors gives rise to high surface area mixed oxides, mainly a mixture of rock-salt phase (NiO), wurtzite phase (ZnO) and sp...

Ethanol steam reforming (ESR) experiments have been performed in dilute conditions over a NiZnAl catalyst. Experiments have been performed by varying catalyst surface area, reactants flow rate, contact time, reactants feed composition and temperature. Acetic acid steam reforming experiments have also been performed. The data suggest that adsorbed a...

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

A water-in-oil microemulsion made up of a cetyltrimethylammonium bromide/n-butanol/isooctane/MII and AlIII nitrate aqueous solution (MII = Mg or Ni or Zn) has been mixed with a microemulsion of the same composition but containing an ammonia solution instead of a metal nitrate solution. Collisions between the reverse micelles containing an MII and A...

The reactions of methanol and ethanol steam reforming (MSR and ESR) have been studied over Cu-ZnO-Al2O3 and over Ni-containing catalysts, respectively. Our spectroscopic studies, coupled with flow reactor studies, allowed us to propose mechanisms for both reactions where water takes the role of oxidant of part of the copper and nickel species. The...

This review is focused on the preparation and potential applications of hydrotalcite like compounds organically modified by ion-exchange procedure and the data reviewed have been supplemented with unpublished results. It is divided in two Parts. Part I deals with intercalation of biologically active species such as amino-acids, anti-inflammatory an...

The direct aza-Diels–Alder reaction between 2-cyclohexen-1-one (1) and benzaldimines 2 in water is reported for the first time. The reaction occurs at 30 °C, is catalyzed by layered α-zirconium hydrogen phosphate (α-ZrP) and requires the presence of sodium dodecyl sulfate (SDS). The reaction yield is excellent, the reaction is faster and the exo di...

Benzoate (Bz), 2,4-dichlorobenzoate (BzDC), and p- and o-hydroxybenzoate (p- and o-BzOH) anions with antimicrobial activity have been intercalated into [Zn(0.65)Al(0.35)(OH)(2)](NO(3))(0.35).0.6H(2)O, layered double hydroxide (LDH), via anion-exchange reactions. The composition of the obtained intercalation compounds, determined by chemical, thermo...

The urea hydrolysis method has been applied to prepare Ni–Zn–Al and Ni–Mg–Al layered double hydroxides (LDHs) to be used as precursors of mixed oxide catalysts for the ethanol steam reforming (ESR) reaction. Well crystallized hydrotalcite-like LHDs have been prepared for both systems. IR spectroscopy provides evidence of the carbonate/nitrate copre...

The invention relates to polymeric materials with which implementing packagings for food products. These packagings retain an active principle able to prolong the shelf life of the contained product and to limit each type of deterioration and/or degradation. It further allows to subject the food product to less drastic and destructive treatments du...

The effects of thermal treatment in the range 25−200 °C of the Zn/Al (ratio 2:1) synthetic hydrotalcites having chloride and carbonate as interlayer anions, of formula [Zn0.65Al0.35(OH)2]Cl0.35·0.35H2O (I) and [Zn0.65Al0.35(OH)2](CO3)0.175·0.69H2O (II), were studied using an integrated X-ray powder diffraction (XRPD)−molecular dynamics (MD) approac...

New heterogeneous catalysts for liquid phase organic synthesis have been obtained by precipitating MgAl-hydrotalcites like compounds according to the urea method in the presence of Sn(IV) and characterised for their composition, thermal behaviour, X-ray diffraction pattern and B.E.T. specific surface area. The anion exchange capacity of the solids...

Intercalation compounds of ZnAl-hydrotalcite with the UV absorber 5-benzoyl-4-hydroxy-2-methoxy-benzenesulphonate acid (4BHF) have been prepared by ion exchange procedure and used to obtain sunscreen stabilization for new cosmetic formulations. Compounds having a sunscreen loading from 26% to 38% w/w have been obtained changing the pH of the equili...

This paper reviews a systematic work, mainly performed in our laboratories, on the intercalation into hydrotalcite-like compounds (HTlc) of anti-inflammatory drugs, sunscreen and antimicrobials species. The paper is divided in three parts, the first part being addressed to the synthesis, structural aspects and intercalation properties of HTlc, the...

ZnAl hydrotalcites containing increasing amounts of 9-anthracenecarboxylate anion (9AC) have been obtained via an anion-exchange procedure. In particular, intercalated and/or surface-exchanged samples were prepared to study the effect of the chromophore packing on their photophysical and photochemical behavior. Surface-exchanged samples were obtain...

Cu/ZnO/Al2O3 catalysts (5–45 Cu at.%) derived from layered double hydroxide (LDH) precursors were studied for oxidative steam reforming of methanol (OSRM). The precursors were prepared by homogeneous precipitation with urea. The catalysts were obtained by thermal decomposition of the precursors and subsequent reduction in H2 stream. XRD, SEM, N2 ad...

Several α-Zr[O3PC6H4SO2NHCH(CH(CH3)2)COOH)]2−x(O3PCH3)x·nH2O samples, containing chiral pendent groups, were prepared by allowing Zr fluoro complexes to decompose in the presence of N-(m-solfophenyl)-l(+)-Valine-phosphonic (PVal) and methanphosphonic (PMe) acids. The layered compounds were characterized by different techniques and left to react wit...

The mesoporous silicate MCM-41 was studied for its properties to adsorb and to influence the photostability and the release of three organic ultraviolet (UV) ray absorbents, namely benzophenone-3 (B3), benzophenone-2 (B2) and p-aminobenzoic acid (PABA). MCM-41 microcrystals have been loaded with the UV absorbents obtaining a good loading w/w percen...

Acrylate and methacrylate anions containing double bond and carboxylic groups, were intercalated in the interlayer region of a layered double hydroxide of formula: [Zn0.66Al0.34(OH)2](NO3)0.34 0.62H2O. The intercalation compounds obtained have been characterized for their chemical composition and with different instrumental techniques (X-ray powder...

New polymeric composite materials containing a nanohybrid to be used for the controlled release of an antibiotic molecule, chloramphenicol succinate, have been formulated, prepared and characterised. The nanohybrid consists of a layered double hydroxide of Mg-Al hydrotalcite-type, in which the nitrate anions present in the host galleries were repla...

A Cu–ZnO–Al2O3 catalyst prepared via hydrotalcite-like hydroxycarbonate precursor, has been tested in the oxidative steam reforming of methanol (MOSR) to produce hydrogen and CO2 with poor CO content in a flow reactor. The conversion of methanol over oxidized, reduced and hydrated catalyst has been investigated by IR spectroscopy. The reactions of...

Mono- and di-carboxyadamantane derivatives were intercalated via ion-exchange procedure onto hydrotalcites with formula [Zn0.65Al0.35(OH)2](A)0.35·nH2O where A is Cl− or ClO4−. Furthermore, an intercalation compound of [Mg0.65Al0.35(OH)2](CO3)0.175·0.5H2O containing the mono-carboxyadamantane has been obtained by using the “memory effect” of the hy...

Recent studies on the intercalation of azoic and xanthenic dyes and of donor–acceptor couples into the interlayer region of hydrotalcite-like compounds (HTlc) will be reviewed. In particular, the synthetic strategy followed to optimize the intercalation of chromophores, together with the chemical, photophysical and photochemical characterization of...

It has been proved that a novel class of catalysts containing only titanium and zinc oxides with different Zn/Ti molar ratio is able to produce hydrogen by methanol reforming. Catalysts were characterised by X-ray diffraction. The influence of the reaction temperature, fed composition and catalyst composition were investigated. The best catalyst pe...

Cu–ZnO–Al2O3 catalysts have been prepared via hydrotalcite-like hydroxycarbonate precursors and tested in the oxidative steam reforming of methanol (MOSR) to produce hydrogen with poor CO content. The surface chemistry of the catalysts has been investigated by IR spectroscopy of low temperature CO adsorption. The aim was to gain indications on the...

Porous zirconium phosphate (P-ZrP) and zirconium benzenephosphonate (P-ZrBP) were prepared in the presence of an anionic surfactant acting as a template. Poorly crystalline materials with a P/Zr molar ratio equal to 2 and having a relatively high surface area and micro/mesoporosity have been obtained. The interaction of myoglobin with the two types...

Intercalation products of Cloisite commercial clay and of Cloisite/polypropylene nanocomposite materials with Rhodamine B dye have been prepared and characterized for chemical composition, X-ray diffraction patterns, thermogravimetric analysis and scanning electron microscopy. They were also investigated by absorption and emission spectroscopies to...

Layered double hydroxides of hydrotalcite (HTlc) type have many applications as matrices in pharmaceutical and cosmetic fields when intercalated with active species in anionic form. The aim of this work was to intercalate 2-phenyl-1H-benzimidazole-5-sulfonic acid (Eusolex 232) (EUS) as sunscreen molecule into hydrotalcites in order to obtain the su...

The use of tetraphosphonic building blocks for the preparation of inorganic-organic zirconium derivatives has led to the formation of novel compounds with a modular structure. This is based on the different connection of polymeric 1D inorganic units covalently connected by organic groups. The different kinds of connections generate two different op...

Non-ionic water-in-oil (w/o) microemulsions of pentaoxyethylenenonylphenyl ether (Igepal-CO520)/cyclohexane/water at 25°C have been used as reaction vessels to obtain zirconium hydrogen phosphate nanoparticles.

In this paper we present the formulation, preparation and characterization of new polymeric composite materials containing a nano-hybrid to be used for the controlled molecular delivery of an anti-inflammatory molecule, Diclofenac. The nano-hybrid consists of a layer of double hydroxide of an Mg-Al hydrotalcite type, in which we replaced the chlori...

A combination of experimental (XRPD) and computational (MD‐simulation) techniques was used for a detailed study of the structural, dynamic and hydration properties of the ZnAl layered double hydroxides (LDHs) of formula [Zn 0.65 Al 0.35 (OH) 2 ]Cl 0.35 · y H 2 O ( I ) and [Zn 0.65 Al 0.35 (OH) 2 ](CO 3 ) 0.175 · y H 2 O ( II ), with y = 0.35 and 0....

The possibility of a wide use of hydrogen as fuel of proton exchange membrane fuel-cells forces to the development of selective catalytic materials for the oxidative steam reforming of methanol (OSRM) to produce H2 essentially free from CO. Cu/ZnO/Al2O3 catalysts of OSRM process have been obtained from hydrotalcite-like precursors with nominal form...

The thermal properties and combustion behaviour of new PE–hydrotalcites nanocomposites are described. Hydrotalcites were synthesized and then intercalated with stearate anion, because of the compatibility of long alkyl chain with polyethylene chains. The presence of inorganic filler shields PE from thermal oxidation, shifting the temperature range...

12-Hydroxydodecanoate (HD) anions were intercalated, via an ion-exchange procedure, onto a Mg/Al hydrotalcite-like compound with the formula [Mg0.65Al0.35(OH)2](NO3)0.35·0.56H2O. The obtained intercalate, characterized by chemical and thermal analyses, X-ray powder diffraction, and Fourier transform infrared spectroscopy, had the formula [Mg0.65Al0...

The technique of high energy ball milling (HEBM) was used to prepare nanocomposites of poly(ε-caprolactone) (PCL) and an organically modified Mg–Al layered double hydroxide. The amount of inorganic material was varied from 0 to 6wt%, and the samples were melted and quenched in ice–water after milling. The molecular weight of PCL decreased and its d...

Traducción de Patente Europea E00938832 (fecha de solicitud, 22/06/2000).-- Titular: Consejo Superior de Investigaciones Científicas (CSIC). El procedimiento comprende poner en contacto metanol, oxígeno, y, opcionalmente, agua, con un catalizador compuesto por óxido de cobre (II), óxido de zinc (II), óxido de aluminio (III) y espinela de cobre (II)...

Cu/ZnO/Al2O3 catalysts derived from a hydrotalcite precursor were studied for oxidative steam reforming of methanol (OSRM), with O2:H2O:CH3OH molar ratios = 0.12:1.1:1. The results were compared with those obtained in nonoxidative steam reforming (SRM) and in partial oxidation (POM) of methanol. The catalysts were highly active for OSRM, giving tot...

Catalysts for oxidative methanol reforming were prepared by thermal and H2-reduction treatments of a precursor consisting mainly of a hydrotalcite-like Cu–Zn–Al hydroxycarbonate and a Zn-rich paratacamite. The precursor was obtained by homogeneous precipitation of metal cations with a properly modified urea method. XRPD and quantitative Rietveld an...

Catalysts for oxidative methanol reforming were prepared by thermal and H2-reduction treatments of a precursor consisting mainly of a hydrotalcite-like Cu-Zn-Al hydroxycarbonate and a Zn-rich paratacamite. The precursor was obtained by homogeneous precipitation of metal cations with a properly modified urea method. XRPD and quantitative Rietveld an...

The adsorption and catalytic activity of myoglobin (Mb) on zirconium phosphonates (a-zirconium benzenephosphonate (alpha-ZrBP), a-zirconium carboxyethanephosphonate (alpha-ZrCEP), and a novel layered zirconium fluoride aminooctyl-N,N-bis(methylphosphonate) (ZrC8)) were investigated. The maximum adsorption was reached after 16 h of contact and was g...

The physical and chemical photo-responses of azobenzene were employed to investigate the ‘nanoscopic’ properties of a layered zirconium phosphonate of formula ZrF(O3PCH2)2NHC8H17 (ZrC8, interlayer distance 1.82 nm), a solid belonging to a new family of zirconium diphosphonates with a poorly hindered interlayer region. Two samples were prepared: an...

The choice of layered phosphates and phosphonates of tetravalent metals, mainly Zr(IV), plays a key role in the success of liquid phase heterogeneous catalysis for the preparation of useful intermediates in organic synthesis. The preparation, the chemical and thermal stability, and the structural aspects of this emerging class of inorganic and inor...

Composite inorganic/organic membranes, formed by dipsersing 10-20% w/w of a zirconium(IV) phosphotungstate powder in Nafion, have been investigated for application in PEFC fed with pure hydrogen and synthetic steam reforming. The hydrophilicity of the composite membranes was found to be higher than that of pure Nafion membranes and this allowed to...

Aqueous solutions of crude extract of lipase from Candida rugosa (C-CRL) and of a semipurified material obtained by treating C-CRL with propan-2-ol (PT-CRL) were used as a source of biomaterial for its adsorption onto the surface of layered micro-crystals of α-zirconium phosphate Zr(HPO4)2 and phosphonates such as Zr(C6H5PO3)2, Zr(HPO4)(C6H5PO3) an...

Addition polymerisation of norbornene with transition metal catalysts activated by methylaluminoxane was first realised on heterogeneous catalytic systems. Advanced inorganic functional polymers possessing anion-exchange properties - layered double hydroxides of Al and Zn of hydrotalcite-type - were applied as supports. They possess high polarity a...

Ni–Al hydrotalcite-like compounds, obtained by precipitation from homogeneous solution accomplished by urea hydrolysis, have been characterised for chemical composition, BET specific surface area, X-ray diffraction and thermogravimetry. The base strength of surface sites was estimated with the method of adsorbed acid–base indicators. A sample of fo...

Ni–Al hydrotalcite-like compounds, obtained by precipitation from homogeneous solution accomplished by urea hydrolysis, have been characterised for chemical composition, BET specific surface area, X-ray diffraction and thermogravimetry. The base strength of surface sites was estimated with the method of adsorbed acid–base indicators. A sample of fo...

Several chromophores with donor–acceptor properties and containing a carboxylic or sulfonic group [coumarin-3-carboxylic acid (3-CCA), 9-anthracenecarboxylic acid (9-ACA), 4-benzoylbenzoic acid (4-BBA) and 2-naphthalenesulfonic acid (2-NSA)] have been intercalated into Mg–Al hydrotalcite-like compounds, both via anion exchange procedures and by usi...

A new layered zirconium diphosphonate fluoride, ZrHF(O3PCH2)2NHC3H6CO2, has been prepared by the reaction of zirconyl chloride with 4-[bis(phosphonomethyl)amino]butanoic acid in the presence of HF. Its structure has been determined “ab initio” by X-ray powder data. It crystallizes in the monoclinic space group P21/c (No. 14), with a = 12.9640(3) Å,...

The synthesis of new intercalation compounds obtained introducing the organic radical 2-(4-carboxyphenyl)-4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazol-1-oxyl-3-oxide (NITpBAH) in layered inorganic hosts via topotactic anion exchange reactions or exchange of anionic ligands is presented. Three different inorganic hosts were employed, two LDH-phases (...

Biocomposites with enzymatic activity were obtained by adsorption of lipase from Candida rugosa on the surface of different layered zirconium phosphates and phosphonates such as α-zirconium hydrogenphosphate, solid dispersions of zirconium phosphate in silica, zirconium carboxyethanephosphonate, zirconium phosphate-carboxyethanephosphonate, zirconi...

The photochromic behaviour of a spirooxazine (1,3,3-trimethylspiro[indoline-2,3-[3H]naphth[2,1-b][1,4]oxazine]) was investigated in a solid matrix at room temperature. The solid matrix belongs to the class of layered zirconium phosphonates and was obtained by slowly decomposing zirconium fluoro complexes in a water methanol solution containing diss...

This paper reports the preparation and characterization of the homologous series of layered zirconium fluoride n-alkylamino-N,N-bis methylphosphonates, of general formula ZrF(O(3)PCH(2))(2)NHC(n)H(2n+1) (n = 1, 2, 3, 4, 5, 6, 8, 9, 10), in which the two phosphonic groups of each diphosphonate building block participate in the assembly of a single l...

Phenolphthalein has been included into Zn–Al hydrotalcite-like compounds by taking advantage of the “memory effect” of hydrotalcites. In particular [Zn0.65Al0.35(OH)2] (CO3)0.1750.5H2O was calcined at 500°C and the obtained mixture of Zn and Al oxides was dispersed in an aqueous alcohol solution containing 7×10−2 mol dm−3 phenolphthalein. The recon...

Phenolphthalein has been included into Zn–Al hydrotalcite-like compounds by taking advantage of the “memory effect” of hydrotalcites. In particular [Zn0.65Al0.35(OH)2] (CO3)0.1750.5H2O was calcined at 500°C and the obtained mixture of Zn and Al oxides was dispersed in an aqueous alcohol solution containing 7×10−2 mol dm−3 phenolphthalein. The recon...

A series of 1-alkanols and 1,omega-alkanediols with chain lengths ranging from 2 to 18 and 2 to 10 carbon atoms, respectively, was intercalated into alpha-Zr(HPO4)(2).H2O by exposing it, intimately dispersed with the guest species, to microwave radiation. The intercalation of 1-hexanol in the presence of different amounts of 1-propanol was also inv...

Titanium phosphate sulfophenylphosphonate, Ti(HPO4)1.00(O3PC6H4SO3H)0.85(OH)0.30·nH2O was synthesised and characterized by X-ray diffraction, solid state NMR, impedance measurements, TG and DSC analysis. The MAS-NMR spectrum of 31P nucleus presents two resonances characteristic of monohydrogen phosphate and sulfophenylphosphonate groups coordinated...

Exchange of Fe3+ and Fe2+ ions into layers of α-zirconium phosphate is achieved in aqueous media by using monosodium and/or ethanolic forms of the host precursor. The products obtained are characterized by chemical analysis, X-ray powder diffraction and Mössbauer spectroscopy. For site assignments, structural modeling is used by combining the measu...

Copper–zinc–aluminum (CZA) catalysts prepared by the homogeneous precipitation of chloride salts in the presence of urea to produce hydrogen selectively by partial oxidation and oxyreforming reactions of methanol were used. The crystalline phases of the precursors and of the air-calcined CZA samples were identified by X-ray diffraction. Temperature...

The xanthene dye fluorescein was immobilized, via anion-exchange reactions, in the interlayer region and/or on the surface of a synthetic Zn−Al hydrotalcite, prepared by the thermal hydrolysis of urea. Surface uptake was investigated by equilibrating [Zn0.67Al0.33(OH)2] [CO3]0.165 0.4 H2O with diluted solutions of fluorescein disodium salt. Only ca...

The physical properties of a series of layer double hydroxides (LDH) of the form [(CO3)0.195(1-x)Cl0.39x(H2O)y]:[Zn0.61Al0.39(OH)2], 0<~x<~1, 0<~y<~(0.4+0.2x) have been studied. The hydration dynamics of these materials indicate that the guest layer water molecules form a hydration ring which defines the height of the solvated, nested Cl anion. The...

We report here the first layer rigidity study which has been performed on layer double hydroxides (LDH's) having a fixed-host layer. The LDH materials studied have the chemical formula [(CO3)0.195(1−x)Cl0.39x]:[Zn0.61Al0.39(OH)2], 0≤x≤1. An inter-layer rigidity parameter of p=4.84±0.06 was determined for these compounds from a fit of the standard v...

The bisphosphonic acids and the corresponding pillared zirconium phosphonates (whose empirical formulae are reported in the title) have been irradiated with γ rays at 3×106 Gy absorbed dose. The effect of irradiation has been proved by performing several physico-chemical measurements (elemental analysis, X-ray powder diffraction, NMR and FT-IR spec...

The intercalation via ion exchange of the azoic dye methyl orange (MO-) into the hydrotalcite-like compound Zn0.67Al0.33(OH)2Cl0.33·0.6H2O has been investigated. X-ray diffraction patterns of samples with increasing dye loading showed that Cl-/MO- exchange occurs with a first-order phase transition from the Cl- phase (interlayer distance 7.74 Å) to...