Urea Hydrolysis Method Research Articles

Mg-Al-La LDH-MnFe2O4 hybrid material for facile removal of anionic dyes from aqueous solutions

The urea hydrolysis method was applied to prepare Mg-Al-La layered double hydroxides (LDH) and its hybrids with different amounts of magnetic MnFe2O4 nanoparticles. The new hybrid materials were characterized by X-ray powder diffraction, FTIR and Raman spectroscopy, AFM, SEM, TEM/EDX microscopic methods, BET specific surface area determination and inductively coupled plasma (ICP). The AFM and TEM/EDX analyses clearly showed MnFe2O4 nanoparticles to be predominantly localized on the surface of LDH sheets. Almost two-fold increase of the specific surface area was observed for the Mg-Al-La LDH-MnFe2O4 hybrids compared to the pristine LDH. All synthesized hybrids were studied for their adsorption capacities of Acid orange 7 dye. The adsorption studies were measured at pH 4.0, 7.0 and 10.0. The resulting data were fitted by Langmuir and Langmuir-Freundlich models. The Langmuir isotherm model exhibited a maximum adsorption capacity of Acid orange 7 dye (687.9 mg/g) for Mg-Al-La LDH-MnFe2O4 hybrid material. The lower pH positively affected higher adsorption capacity of Acid orange 7 dye. The prepared Mg-Al-La LDH-MnFe2O4 hybrid materials thus showed to be new promising adsorbents of anionic dyes.

Synthesis and Characterization of Polystyrene (PS)/Modified Ni‐Al LDH Nanocomposite: Role of Composition, Modifier and Synthesis Route of Layered Double Hydroxides (LDH)

Layered double hydroxides (LDH) are two‐dimensional nanostructured materials, which impart flame retardancy property and improvement in various properties on incorporation into the polymer matrix. In this study, Ni‐Al LDH with a molar ratio of 2:1 and 3:1 (2NiAl and 3NiAl) was prepared by co‐precipitation method and Ni‐Al LDH with a molar ratio of 2:1 (NiAl urea) was also synthesized by the urea hydrolysis method. As the d‐spacing of these as‐synthesized LDHs is very small (≈0.8 nm) as well as hydrophilic in nature, hence, the unmodified LDHs are unsuitable for polymer nanocomposite preparation. In order to enhance the d‐spacing of LDHs, a simple regeneration method was employed to organically modify LDHs using two anionic surfactants such as sodium dodecyl benzene sulfate (SDBS) and sodium dodecyl sulfate (SDS). The hydrophobic tail of these anionic surfactants replaced the nitrate ions present in the unmodified LDHs leading to higher d‐spacing value, which was evident from XRD analysis. The above prepared LDHs (3 wt%) were incorporated into PS matrix by the solvent blending method to make PS nanocomposites. The 003 peak of modified LDHs did not appear in the XRD pattern of PS nanocomposites due to the disorientation of LDH layers in the PS matrix that was confirmed by TEM analysis. The TGA results clearly demonstrated that the thermal stability of the PS nanocomposite samples was increased by 26, 22 and 22 °C (PS/2NiAl SDS, PS/3NiAl SDS, and PS/NiAl urea SDS) for SDS modified LDH fillers, while in the case of SDBS modified LDH fillers, the improvement was around 32 °C in comparison with PS, when 15% weight loss was taken as a reference. The degradation mechanism, thermal degradation kinetics, and integral procedural decomposition temperature (IPDT) for all the nanocomposite systems were also evaluated using Criado method, Coats‐Redfern method, and Doyle's method, respectively. The effect of dispersion of the modified LDH fillers into PS matrix was examined using melt rheological analysis.

Hydrogenation of methyl levulinate to γ‐valerolactone over Cu─Mg oxide using MeOH as in situ hydrogen source

AbstractBACKGROUNDγ‐Valerolactone (GVL) is a versatile biomass‐derived platform molecule that could serve as a building block to produce chemicals, materials and fuels, but the production of GVL from biomass via a cost‐competitive method is challenging. In this contribution, a robust Cu─Mg oxide was prepared as an efficient bifunctional catalyst for both H2 production by MeOH reforming and hydrogenation of methyl levulinate (ML) to GVL in MeOH medium.RESULTSCu0.87Mg0.13Ox prepared by a urea hydrolysis method offered a GVL yield up to 90.6% at 220°C in 4 h without external hydrogen. This catalyst could be reused for at least seven consecutive cycles without loss of its activity. Notably, Cu0.87Mg0.13Ox also provided nearly 70% GVL yield in methanolysis products of cellulose in the presence of humins. Characterization of the catalyst indicates that the incorporation of MgO greatly facilitates the stabilization of Cu+ species that possess a better catalytic performance in ML hydrogenation compared with metallic Cu.CONCLUSIONThis robust Cu0.87Mg0.13Ox could greatly contribute to develop a highly facile and desirable two‐step strategy for GVL production from cellulose, through the integration of ML production by methanolysis of cellulose, H2 formation by MeOH reforming and ML hydrogenation in MeOH medium. © 2018 Society of Chemical Industry

Synthesis of Mg/Al Layered Double Hydroxides for Adsorptive Removal of Fluoride from Water: A Mechanistic and Kinetic Study

Herein, we report the synthesis of Mg/Al-CO3 layered double hydroxides (LDHs) by the urea hydrolysis method under hydrothermal conditions at different aging times. The LDHs were characterized by different microscopic, spectroscopic, diffractometric, and thermal analysis techniques. The as-prepared LDHs were then used as adsorbents for the removal of fluoride ions from water. The adsorption process was systematically studied in terms of influences of pH, interaction time, temperature, adsorbent loading, fluoride ion concentration, and the effect of coexisting anions to understand the ideal conditions for adsorption. The adsorption process primarily followed pseudo-second-order kinetics. The Langmuir monolayer adsorption capacities of different adsorbents are in the range of 15.13–27.03 mg g–1 at 303 K. The hydrothermal aging time has a negative impact on the adsorption capacities of the LDHs. The as-prepared LDHs are reusable up to five cycles of the fluoride ion adsorption–desorption process.

Low temperature synthesized SrMoO4:Eu3+ nanophosphors functionalized with ethylene glycol: A comparative study of synthesize route, morphology, luminescence and annealing

Tetragonal SrMoO4:Eu3+ downconverting phosphors functionalized with ethylene glycol have been synthesized via three different preparation techniques (urea hydrolysis, ammonia hydrolysis and hydrothermal methods). The developed phosphor shows strong red photoluminescence emission via electric dipole 5D0 → 7F2 transition and other weak transitions (5D1 → 7F1, 5D0 → 7F1, 5D0 → 7F3 and 5D0 → 7F4) by using three excitation wavelengths of 260, 395 and 464 nm. For the first time, a comprehensive discussion have been given for indirect and direct excitation for as-prepared phosphor prepared by the three different techniques. The needle imbedded spherical particles, elliptical shaped particles and orange carpels shaped particles have been obtained from the urea, ammonia and hydrothermal methods, respectively. The calculated quantum yields are found to be 7.5, 6.1 and 9.3% for urea, ammonia and hydrothermal based synthesized phosphors, respectively. The prepared phosphors are suitable for biological labeling due to their dispersible ability in different liquids (ethanol, phosphate buffered saline and water).

Effect of calcination temperature on the physicochemical and catalytic properties of SZSBA-15 catalyst in the production of monopalmitin

ABSTRACTSulfated zirconia on SBA-15 catalysts with different calcination temperatures (450, 550, 600 and 650°C) were synthesized through urea hydrolysis method. The catalysts were characterized using N2 adsorption–desorption analysis, scanning electron microscopy, energy dispersive X-ray, transmission electron microscopy, thermogravimetric analysis, temperature-programmed desorption of ammonia (NH3–TPD), X-ray diffraction, and determination of surface acidity by HCl titration method. The catalyst’s characteristics and their correlation with the catalytic activity in the esterification of palmitic acid with glycerol were particularly investigated. The characterization results revealed that the morphology of all catalysts remained virtually unaffected with increasing calcination temperature but the surface area and pore volume of the catalysts showed some reduction. Pore diameter was not significantly affected by the calcination temperature which indicated the stability of the porous catalysts. Furthermore, the increase in the calcination temperature exceeding 600°C would reduce the catalytic activity toward monopalmitin due to a decrease in the active acid sites concentration and acidic strength of the catalyst as a result of sulfur decomposition.

La-promoted Ni/Mg-Al catalysts with highly enhanced low-temperature CO2 methanation performance

In this paper, we investigated the effect of adding lanthanum on the structure and low-temperature activity of the Ni/Mg-Al catalyst for CO2 methanation. A series of La-doped Ni/Mg-Al catalysts with different La loadings were synthesized by urea hydrolysis method. The results showed that La-promoted NiLax (x = 2, 5 and 8 wt%) catalysts exhibited higher low-temperature activity than the Ni catalyst without La added. In particular, the NiLa5 catalyst performed the best, getting as high as 61% CO2 conversion and nearly 100% CH4 selectivity at 250 °C, 0.1 MPa, and a WHSV of 45,000 mL g−1 h−1. Characterization results revealed that La effectively increased Ni dispersion and decreased Ni particle size. In addition, La could significantly increase the amount of moderate basic sites, which contributed to enhanced CO2 adsorption capacity. Compared with coprecipitation method, urea hydrolysis method was proved to be a more efficient approach for the Ni-based catalyst preparation, getting the Ni-based catalyst with higher Ni dispersion, larger CO2 adsorption capacity and thereby better catalytic performance.

Synthesis of Nickel-Aluminium Layered Double Hydroxide and itsApplication in Non-Enzymatic Glucose Sensing

In this work Nickel-Aluminium layered double hydroxide (LDH) was successfully synthesized via urea hydrolysis method. This involves the digestion of aluminium sulphate, nickel sulphate and urea at 90 ⁰C for 24 hours. Atomic force microscopic (AFM) studies revealed the presence of highly ordered layers and the Ni-Al LDH was observed to be in the hexagonal cubic crystalline structure through X-ray diffraction studies. The prepared compound was utilized for fabrication of a non-enzymatic electrochemical glucose sensor. Glucose oxidation on the sensor occurred at 0.6 V in 0.1 M NaOH. The sensor exhibited a sensitivity of4.12 µA/mM/cm2 with linearity upto28 mM. The developed sensor was sensitive towards glucose in the presence of common interfering molecules such asascorbic acid, uric acid, dopamine and creatinine.

Effects of zirconia loading in sulfated zirconia/SBA-15 on esterification of palmitic acid with glycerol

Sulfated zirconia supported on SBA-15 (SZSBA-15) catalysts with different zirconia loadings (5–20 wt%) were synthesized using urea hydrolysis method. Effects on the physicochemical properties of the catalysts and activity in selective glycerol esterification with palmitic acid were particularly investigated. Various characterization techniques such as N2 adsorption-desorption analysis, SEM, TEM, TGA, FTIR, NH3-TPD and acidity measurement by titration were used. Increasing zirconia loading decreased the surface area, pore size and pore volume of the catalysts, but increased the sulfate content and improved the catalyst acidity. Larger surface area was not the major factor in determining the catalyst activity especially in the reaction involving bulky molecules. The reaction was found to be influenced by the amount of active sites presence on the catalyst and also by the dimension of the pores which slightly promoted the shape selective reaction. Among all catalyst, 15SZSBA-15 demonstrated the highest activity with 88% conversion and 44% monopalmitin yield.

Some Attributes of Mn3+ Sites in Nickel‐Based Layered Double Hydroxides during Methanol Electro‐oxidation in Alkaline Media

AbstractNi‐based layered double hydroxides (LDHs), or hydrotalcite‐like materials (HTs), were synthetized through co‐precipitation at constant pH (NiAl and NiMg) and urea hydrolysis (NiMn) methods, and they were tested in the electrochemical methanol oxidation (MOR). The physicochemical properties were explored by using techniques such as X‐ray diffraction, FT‐IR spectroscopy, as well as electron paramagnetic resonance. In addition, correlation between active site arrangements and electrocatalytic activity was evidenced by density functional calculations. Specific site μ(Ni2Mn‐OH) showed the lowest proton energy removal at approximately 3.6 eV and the NiMn LDH sample containing a higher proportion of this site exhibited the best performance for the MOR process, with an enhancement factor of 5.16, which is attributed to limited deactivation of Ni during the reaction. CO2 production was detected by differential electrochemical mass spectrometry to be on the order of ten times greater than O2.

Comparison of adsorption and desorption of phosphate on synthesized Zn-Al LDH by two methods in a simulated soil solution

Abstract Zinc aluminum layered double hydroxides (LDH) with Zn/Al molar ratios of 2 and 3 were synthesized by general (Zn 2G -Al, Zn 3G -Al) and modified (Zn 2M -Al, Zn 3M -Al) urea hydrolysis methods. The effects of time, pH, selectivity and initial phosphorous concentration were investigated on phosphate uptake by synthesized LDH in a simulated soil solution. Moreover, phosphate desorption from studied LDH was evaluated. Based on the results, nitrate containing Zn-Al LDH were synthesized by both methods. However, the presence of carbonate ion in the interlayer space of Zn 3G -Al was recorded. The kinetics experiments indicated that the pseudo-second order model well described phosphate uptake on all LDH. The lowest uptake (1.09 mmol g − 1 ) was observed for Zn 3G -Al likely due to Zn/Al molar ratio, the presence of carbonate in the interlayer space and incomplete phosphate intercalation mechanism. Phosphate adsorption isotherms of LDH were in agreement with Freundlich model. Although phosphate uptake decreased in the presence of other anions, the highest selectivity especially in the pure nitrate containing LDH were measured for phosphate anion. Phosphate uptake declined with increasing the pH from 6 to 8. The amounts of phosphate desorption from prepared LDH were between 23.2 and 36.3% suggesting that synthesized LDH may have potential to be used as a slow release phosphate fertilizer in soils.

Highly active Cu-Zn-Mg-Al-O catalyst derived from layered double hydroxides (LDHs) precursor for selective hydrogenolysis of glycerol to 1,2-propanediol

Selective hydrogenolysis of glycerol to 1,2-propanediol (1,2-PDO) was performed by using environmentally friendly bifunctional layered double hydroxide (LDHs) type Cu-Mg-Al-O and Cu-Zn-Mg-Al-O catalysts prepared by urea hydrolysis method. The physicochemical properties of these catalysts were characterized by various techniques such as specific surface area (BET), X-ray Diffraction (XRD), H2-temperature programmed reduction (TPR) and scanning electron microscopy (SEM) etc. Ball-flower shaped particles were identified in SEM images of all the catalysts and a well-defined layered structure of solid lamella has also been identified. The SEM images confirmed the formation and stability of LDHs type structure of the catalysts even after calcination and reduction. The catalytic activity results depicted that, very high catalytic activity (>80%) with very high selectivity (>90%) to 1,2-PDO was obtained over all the catalyst synthesized. However, among all other, Cu-Zn-Mg-Al-O catalyst was the most active and selective to 1,2-PDO. The synergic interaction between the copper and ZnO on LDHs support, high reducibility, small Cu particle size and well-developed curved platelet structure were solely responsible for better catalytic activity of Cu-Zn-Mg-Al-O catalyst as compared to Cu-Mg-Al-O catalyst. The maximum glycerol conversion of 98.4% with 94.3% selectivity to 1,2-PDO was achieved over Cu-Zn-Mg-Al-O catalyst at optimum reaction condition i,e. at 210°C, at 4.5MPa pressure after 12h of reaction in presence of 1g of NaOH as additive. The selectivity (>94%) to 1,2-PDO was almost unchanged even after cycle-3 although the activity was reduced significantly.

Lanthanum-Based Compounds: Electronic Band-Gap-Dependent Electrocatalytic Materials for Oxygen Reduction Reaction.

The electronic energy level of lanthanum compounds plays an important role in the oxygen reduction reaction (ORR) electrocatalytic process. In this work, three lanthanum compounds, LaOHCO3 , La2 O2 CO3 , and La2 O3 , have been synthesized through an in situ urea hydrolysis method, followed by annealing at different temperatures. Among these lanthanum compounds, the layer-structured La2 O2 CO3 has the smallest band gap and moderate values of the conduction band (CB) and valence band (VB). Electrochemical measurements in 0.1 m KOH solution have shown that, compared with the other catalysts, La2 O2 CO3 exhibits the best electrocatalytic activity with the lowest H2 O2 production and highest durability for ORR, which proves the close correlation between electronic energy level and electrocatalytic ORR activity. During the ORR process over La2 O2 CO3 , some covalent electrons from the VB are first excited to the CB and then transfer to the unoccupied π*2p orbitals of an active oxygen molecule, leading to strengthened oxygen adsorption and promotion of the reduction of oxygen. Moreover, La2 O2 CO3 has an ability to chemically disproportionate hydrogen peroxide (to give HO2- ), and the produced HO2- at the energy level of O2 /HO2- can undergo prompt chemical disproportionation into O2 and OH- . The O2 generated at this stage is adsorbed on the catalyst surface, which can be utilized for further oxygen reduction.

Preparation and application of Cu/ZnO catalyst by urea hydrolysis method for low-temperature methanol synthesis from syngas

The Cu/ZnO catalyst prepared by urea hydrolysis method was investigated for low-temperature methanol synthesis from syngas containing CO2. Concurrently, the activity of the conventional Cu/ZnO catalyst prepared by co-precipitation method was also compared. The effects of precipitation temperature, urea content, stirring speed and the introduction of Al on the catalytic performance of Cu/ZnO were deeply studied. It was found that the total carbon conversion of the Cu/ZnO catalyst prepared by urea hydrolysis method was increased to 45.0% from 32.8%, comparing with that of the catalyst prepared by co-precipitation method. The structure, BET surface area, surface morphology of the catalyst were characterized by XRD, BET, EDX and SEM. The catalyst prepared by urea method obtained higher BET surface area and larger metallic surface area of Cu than those of the co-precipitation method. The crystals sizes of Cu by urea method were smaller than those of co-precipitation method. Surface structure prepared by urea method had needle shape, and it could increase the surface area, different from the catalyst by co-precipitation method. Both the increased BET surface area of the catalysts and the enhanced metallic surface area of Cu0 promoted the catalyst activity for the low-temperature methanol synthesis. The deactivation of the Cu-ZnO catalysts prepared by urea method was not observed in low-temperature methanol synthesis here.

The Controllable Synthesis of Octadecahedral BiVO4 with Exposed {111} Facets

Urea was used as a reactant and base retardant for the controllable synthesis of octadecahedral BiVO4 (OD‐BiVO4) with exposed {111}, {010}, {011}, and {110} facets. The samples were characterized by X‐ray diffraction (XRD), scanning electron microscopy (SEM), UV/Vis spectroscopy, and Raman spectroscopy. The effect of the urea molecules on the morphology of BiVO4 was studied. The urea molecules show a preferential adsorption on the {111}, {010}, {011}, and {110} facets of BiVO4, and the urea molecules on the {111} facets retard the growth of the {010}, {011}, and {110} facets. The growth of BiVO4 in ammonia solution and through the urea hydrolysis method was studied in detail. The photocatalytic efficiency of OD‐BiVO4 for the photodegradation of rhodamine B was also studied.

In Situ Formation of Decavanadate-Intercalated Layered Double Hydroxide Films on AA2024 and their Anti-Corrosive Properties when Combined with Hybrid Sol Gel Films.

A layered double hydroxide (LDH) film was formed in situ on aluminum alloy 2024 through a urea hydrolysis method, and a decavanadate-intercalated LDH (LDH-V) film fabricated through the dip coating method. The microstructural and morphological characteristics were investigated by scanning electron microscopy (SEM). The corrosion-resistant performance was analyzed by electrochemical impedance spectroscopy (EIS), scanning electrochemical microscopy (SECM), and a salt-spray test (SST).The SEM results showed that a complete and defect-free surface was formed on the LDH-VS film. The anticorrosion results revealed that the LDH-VS film had better corrosion-resistant properties than the LDH-S film, especially long-term corrosion resistance. The mechanism of corrosion protection was proposed to consist of the self-healing effect of the decavanadate intercalation and the shielding effect of the sol-gel film.

Morphology controlled phosphate grafted SnO2–ZrO2 nanocomposite oxides prepared by a urea hydrolysis method as efficient heterogeneous catalysts towards the synthesis of 3-substituted indoles

In this study, a series of phosphate grafted SnO2–ZrO2 nanocomposite oxides are prepared via the urea hydrolysis method and evaluated as catalyst for synthesis of 3-substituted indoles.

ChemInform Abstract: Ba/ZrO2 Nanoparticles as Efficient Heterogeneous Base Catalyst for the Synthesis of β‐Nitro Alcohols and 2‐Amino 2‐Chromenes.

Zirconia nanoparticles were synthesized by precipitation, urea hydrolysis, amorphous citrate and combustion synthesis methods. The zirconia surface was subsequently modified by grafting Ba 2+ species. The Ba 2+ modified zirconia (Ba/ZrO 2) materials were characterized using XRD, Fourier analysis, UV-vis-DRS, FESEM and HRTEM techniques. XRD study indicated selective stabilization of the tetragonal phase of zirconia in the presence of Ba 2+ species. Fourier line profile analysis of the XRD peaks revealed that the average crystallite size of the zirconia nanoparticles is in the range of 5-15 nm. The surface area, basicity and barium content of the material depend strongly on the method of synthesis. The Ba/ZrO 2 catalyst prepared by urea hydrolysis method exhibited higher surface area and barium content compared to other samples. The catalytic activity of the Ba/ZrO 2 catalyst was evaluated for synthesis of β-nitro alcohols and 2-amino 2-chromenes. The β-nitro alcohols were synthesized by condensation of aryl aldehydes and nitromethane. Similarly, the 2-amino 2-chromenes were synthesized by condensation of arylaldehydes, α-naphthol and malononitrile. The Ba/ZrO 2 catalyst was found to be highly efficient for synthesis of both classes of compounds providing excellent yield and purity of the products.

CaO-ZrO2 nanocomposite oxide prepared by urea hydrolysis method as heterogeneous base catalyst for synthesis of chromene analogues

A series of CaO–ZrO2 nanocomposite oxides containing 2–50mol% of CaO were synthesized employing urea as a mild hydrolyzing agent. The nanocomposite systems were characterized using XRD, Fourier analysis, TPD, Raman, XPS, TGA-DSC, FESEM, HRTEM, and BET surface area measurement techniques. XRD study indicated selective stabilization of the tetragonal zirconia phase in the composite oxide. Upto 20mol% CaO, the Ca2+ ions substituted for Zr4+ ions in the zirconia lattice to form a substitutional solid solution. Beyond 20 mol% CaO, the presence of a mixed phase system consisting of the solid solution phase, CaO and nonstoichiometric Zr0.93O2 phase was observed. The composite oxides contain crystallites with size <20nm as observed from Fourier and HRTEM analysis. TPD study revealed a significant enhancement in the basicity of zirconia as a result of Ca2+ incorporation. XPS study confirmed presence of different lattice oxygen as potential basic sites. Raman spectral data indicated the presence of oxygen vacancy and distortion in oxygen sublattice due to Ca2+ incorporation to zirconia. Microscopic investigation of the composite oxide suggested a gradual morphological change from rod shape particles to flake like and subsequently to cubic morphology with increase in CaO content in the composite. The CaO–ZrO2 nanocomposite oxides were used as an efficient and recyclable heterogeneous base catalyst for synthesis of chromene analogues. Structurally diverse 2-amino-4H-chromenes and 2-amino-2-chromenes were synthesized in high yield and purity under mild condition using CaO-ZrO2 material as catalyst and multicomponent condensation approach.

Ba/ZrO2 nanoparticles as efficient heterogeneous base catalyst for the synthesis of β-nitro alcohols and 2-amino 2-chromenes

Zirconia nanoparticles were synthesized by precipitation, urea hydrolysis, amorphous citrate and combustion synthesis methods. The zirconia surface was subsequently modified by grafting Ba 2+ species. The Ba 2+ modified zirconia (Ba/ZrO 2) materials were characterized using XRD, Fourier analysis, UV-vis-DRS, FESEM and HRTEM techniques. XRD study indicated selective stabilization of the tetragonal phase of zirconia in the presence of Ba 2+ species. Fourier line profile analysis of the XRD peaks revealed that the average crystallite size of the zirconia nanoparticles is in the range of 5-15 nm. The surface area, basicity and barium content of the material depend strongly on the method of synthesis. The Ba/ZrO 2 catalyst prepared by urea hydrolysis method exhibited higher surface area and barium content compared to other samples. The catalytic activity of the Ba/ZrO 2 catalyst was evaluated for synthesis of β-nitro alcohols and 2-amino 2-chromenes. The β-nitro alcohols were synthesized by condensation of aryl aldehydes and nitromethane. Similarly, the 2-amino 2-chromenes were synthesized by condensation of arylaldehydes, α-naphthol and malononitrile. The Ba/ZrO 2 catalyst was found to be highly efficient for synthesis of both classes of compounds providing excellent yield and purity of the products. The surface modification of zirconia nanoparticles was carried out by grafting Ba2+ species to generate a heterogeneous catalyst which exhibits efficient catalytic activity for base catalyzed synthesis of b-nitro alcohols and 2-amino 2-chromenes.