Aqueous Ammonia Solution Research Articles

Revealing specific features of structure formation in composites based on nanopowders of synthesized zirconium dioxide

Peculiarities of formation of microstructure in composites based on chemically synthesized zirconium nanopowders obtained by the method of decomposition from fluoride salts were considered. Hydrofluoric acid, concentrated nitric acid, aqueous ammonia solution, metallic zirconium, and polyvinyl alcohol were used. It was established that the reduction of porosity in nanopowders in the sintering process is the main problem in the formation of high-density materials. Analysis of various initial nanopowders, their morphology, and features of sintering by the method of hot pressing with direct transmission of electric current was made. Peculiarities of obtaining the composites based on them with the addition of Al2O3 nanopowders applying the electric sintering method were considered. It was shown that the increase in the content of alumina nano additives leads to an increase in strength and crack resistance of the samples due to simultaneous inhibition of abnormal grain growth and formation of a finer structure with a high content of tetragonal phase. The influence of sintering modes on the formation of the microstructure of zirconium nanopowders has been studied for different contents of alumina additives. Electric current promotes the surface activity of nanopowders and its variable value promotes partial fragmentation of agglomerated grains thus affecting the composite structure. Physical-mechanical properties of the obtained samples, optimal compositions of mixtures, and possibilities of improving some parameters were determined. It was found that nanopowders of zirconium dioxide obtained by the method of decomposition from fluoride salts are quite suitable for the production of composite materials with high physical and mechanical properties. They can compete with imported analogs and enable obtaining of crack resistance of 7.8 MPa·m1/2 and strength of 820 MPa.

(Keynote) Electrochemical Routes to Nitrogen Fixation: Comparisons, Pitfalls and Breaking in through the Cat Flap

The electrosynthesis of ammonia from nitrogen and water is a topic of considerable interest in the quest for sustainable and decentralized NH3 production (Catal. Today, 2017, 286, 57-68). It is, however, a remarkably difficult process to perform and the literature abounds with false-positives for electrochemical ammonia generation. In this talk, we shall survey some of the approaches for electrochemical nitrogen fixation that have been proposed, before then examining in detail one example from the author’s laboratory of a false-positive for nitrogen reduction electrocatalysis. In this example, tin(II) phthalocyanine complexes (previously reported as active electrocatalysts for nitrogen reduction to ammonia in aqueous solution), were shown not to be electrocatalysts for this transformation at all, with the amount of ammonia detected being essentially the same under N2 and under Ar. Instead, apparent ammonia generation was shown to be a consequence of contaminants in the as-prepared tin(II) phthalocyanine complexes (Electrochim. Acta, 2017, 258, 618-622). Finally, we shall discuss alternative mechanisms for nitrogen fixation that do not rely on the direct reduction of dinitrogen to ammonia in aqueous solution.

Aqueous Ammonia Wetting & Evaporation on Gas-Diffusion Layers

Recent interest in electrochemical technologies for low temperature ammonia production motivates the need to understand key mass transport behavior at the electrode/flow-field interface. This work measures wetting properties as well as evaporation rates of aqueous ammonia solutions from the surface of porous carbon based gas-diffusion layers (GDL). These materials are commonly used in membrane-electrode assemblies (MEA) which are at the heart of electrolytic ammonia synthesis and direct ammonia fuel cell (DAFC) systems. Aqueous ammonia solutions of 0%, 10%, and 20% NH3 concentration by weight were micropipetted onto the surfaces of Toray 120 GDL. Droplet dimensions and mass were recorded with respect to time using a digital scale and automated goniometer. An environmental chamber mounted to the goniometer was used to conduct the higher temperature tests at 60 ⁰C and 100 ⁰C. The impact of concentration, and temperature on key wetting behavior and evaporation rates was probed. Droplet evaporation rates, initially dominated by NH3, fall as the ammonia concentration decreases. Higher NH3 concentrations lead to higher initial evaporation rates. Elevated temperatures increased the evaporation rates in all cases. Slow nucleate boiling was observed in the droplets for the 100 ⁰C cases. Overall, wetting throughout the evaporation process is dominated by pinning effects as the droplet contact widths remained constant with falling height and contact angles. The impact on concentration was also investigated on breakthrough pressure and adhesion force which have been previously demonstrated to be useful metrics for gauging material performance by the polymer-electrolyte-membrane fuel cell (PEFC) community. Higher NH3 solutions reduced the breakthrough pressure and also lead to higher adhesion force to the GDL surface. The effect of GDL hydrophobic coatings (PTFE wt. %) on these metrics was found to be insignificant over 10%.

Matching of models of Titan with tidal Love numbers

The restrictions on the heat flux, the structure of the water-ice shell, and the composition of the Titan ocean, which are necessary to match the calculated (model) and experimental Love numbers, are considered. Estimates are obtained for model Love numbers and maximum surface heat fluxes for the L/LL chondrite composition of the rock-iron component of Titan, taking into account the radiogenic and tidal energy, as well as the energy of ice crystallization in the ocean due to satellite cooling. The values of the tidal Love numbers k2 of Titan were calculated for various models of the water-ice shell of the satellite, including the outer ice crust (ice Ih ± CO2 clathrates) and the internal ocean of various compositions (pure or sea water, ammonia + dissolved salts solution, aqueous solutions of ammonia and methanol). Titan models with an outer ice crust (ice Ih + 5% CO2 clathrates) and with an internal ocean of low salinity based on ammonia (5% NH3) aqueous solution better than other tested models satisfy the k2 experimental values.

Carbamoyl phosphate and its substitutes for the uracil synthesis in origins of life scenarios

The first step of pyrimidine synthesis along the orotate pathway is studied to test the hypothesis of geochemical continuity of protometabolic pathways at the origins of life. Carbamoyl phosphate (CP) is the first high-energy building block that intervenes in the in vivo synthesis of the uracil ring of UMP. Thus, the likelihood of its occurrence in prebiotic conditions is investigated herein. The evolution of carbamoyl phosphate in water and in ammonia aqueous solutions without enzymes was characterised using ATR-IR, 31P and 13C spectroscopies. Carbamoyl phosphate initially appears stable in water at ambient conditions before transforming to cyanate and carbamate/hydrogenocarbonate species within a matter of hours. Cyanate, less labile than CP, remains a potential carbamoylating agent. In the presence of ammonia, CP decomposition occurs more rapidly and generates urea. We conclude that CP is not a likely prebiotic reagent by itself. Alternatively, cyanate and urea may be more promising substitutes for CP, because they are both “energy-rich” (high free enthalpy molecules in aqueous solutions) and kinetically inert regarding hydrolysis. Energy-rich inorganic molecules such as trimetaphosphate or phosphoramidates were also explored for their suitability as sources of carbamoyl phosphate. Although these species did not generate CP or other carbamoylating agents, they exhibited energy transduction, specifically the formation of high-energy P–N bonds. Future efforts should aim to evaluate the role of carbamoylating agents in aspartate carbamoylation, which is the following reaction in the orotate pathway.

Fabrication of Humidity-Resistant Optical Fiber Sensor for Ammonia Sensing Using Diazo Resin-Photocrosslinked Films with a Porphyrin-Polystyrene Binary Mixture.

Ammonia gas sensors were fabricated via layer-by-layer (LbL) deposition of diazo resin (DAR) and a binary mixture of tetrakis(4-sulfophenyl)porphine (TSPP) and poly(styrene sulfonate) (PSS) onto the core of a multimode U-bent optical fiber. The penetration of light transferred into the evanescent field was enhanced by stripping the polymer cladding and coating the fiber core. The electrostatic interaction between the diazonium ion in DAR and the sulfonate residues in TSPP and PSS was converted into covalent bonds using UV irradiation. The photoreaction between the layers was confirmed by UV-vis and Fourier transform infrared spectroscopy. The sensitivity of the optical fiber sensors to ammonia was linear when exposed to ammonia gases generated from aqueous ammonia solutions at a concentration of approximately 17 parts per million (ppm). This linearity extended up to 50 ppm when the exposure time (30 s) was shortened. The response and recovery times were reduced to 30 s with a 5-cycle DAR/TSPP+PSS (as a mixture of 1 mM TSPP and 0.025 wt% PSS in water) film sensor. The limit of detection (LOD) of the optimized sensor was estimated to be 0.31 ppm for ammonia in solution, corresponding to approximately 0.03 ppm of ammonia gas. It is hypothesized that the presence of the hydrophobic moiety of PSS in the matrix suppressed the effects of humidity on the sensor response. The sensor response was stable and reproducible over seven days. The PSS-containing U-bent fiber sensor also showed superior sensitivity to ammonia when examined alongside amine and non-amine analytes.

Pretreatment of Corn Stover Using an Extremely Low-Liquid Ammonia (ELLA) Method for the Effective Utilization of Sugars in Simultaneous Saccharification and Fermentation (SSF) of Ethanol

Extremely low-liquid ammonia (ELLA) pretreatment using aqueous ammonia was investigated in order to enhance the enzymatic saccharification of corn stover and subsequent ethanol production. In this study, corn stover was treated with an aqueous ammonia solution at different ammonia loading rates (0.1, 0.2, and 0.3 g NH3/g biomass) and various liquid-to-solid (L/S) ratios (0.55, 1.12, and 2.5). The ELLA pretreatment was conducted at elevated temperatures (90–150 °C) for an extended period (24–120 h). Thereafter, the pretreated material was saccharified by enzyme digestion and subjected to simultaneous saccharification and fermentation (SSF) tests. The effects of key parameters on both glucan digestibility and xylan digestibility were analyzed using analysis of variance (ANOVA). Under optimal pretreatment conditions (L/S = 2.5, 0.1 g-NH3/g-biomass, 150 °C), 81.2% glucan digestibility and 61.1% xylan digestibility were achieved. The highest ethanol yield achieved on the SSF tests was 85.4%. The ethanol concentration was 14.5 g/L at 96 h (pretreatment conditions: liquid-to-solid ratio (L/S) = 2.5, 0.1 g-NH3/g-biomass, 150 °C, 24 h. SSF conditions: microorganism Saccharomyces cerevisiae (D5A), 15 FPU/g-glucan, CTech2, 3% w/v glucan, 37 °C, 150 rpm).

Preparation of polyvinyl alcohol reinforced with microcrystalline cellulose to function as test strips immobilized with a hydrazone chromophore for colorimetric identification of toxic ammonia

Ammonia is a colorless gas that has been known as one of the most toxic gases. It may cause irritations to nose, eyes, as well as organ failure and even death. Hence, it is of high significance to assemble an onsite detection device for aqueous and gaseous ammonia. Herein, we develop a highly sensitive and inexpensive microporous composite test strip for ammonia. An easy-to-prepare colorimetric tricyanofuran-hydrazone (TCFH) dye was synthesized and encapsulated into microporous polyvinyl alcohol/microcrystalline cellulose (PVOH-MCC) composite. PVOH-MCC-TCFH demonstrated bathochromic shift of 126 nm with increasing the concentration of ammonia. The colorimetric changes of PVOH-MCC-TCFH after exposure to methanolic solution (pH ∼7.0) of ammonia were monitored. This color shifts can be attributed to delocalization of electrons in the tricyanofuran-hydrazone molecular structure. The hydrazone binding sites was found to selectively sense ammonia over a sequence of other aliphatic and aromatic amines. The color shifts of PVOH-MCC-TCFH depended on the total content of ammonia in aqueous solution. The determination limit of NH3(aq) was observed between 5 and 200 ppb. The morphology, thermal stability and fibrous crystallinity of the produced PVOH-MCC-TCFH sensor strips were explored by different spectral techniques. The microporous structure of PVOH-MCC immobilized with TCFH demonstrated highly porous scaffolds with pore diameters of 25–35 to 50–100 μm depending on the total content of TCFH. The mechanical performance of the prepared PVOH-MCC-TCFH sensor strips was also explored.

Conditions for the Development of Phase Components K2CaP2O7 , KCaP3O9 in Toxic Dust

The present study analyses the composition and main components of toxic dust. To develop and understand the methods of controlling the dust generation process, it is necessary to study the data that provide detailed information about the reaction mechanism. The results of studies of the phase composition of dust conducted in the laboratory and their comparison with the data obtained earlier by other authors allowed establishing a fairly reliable diagnosis of the phase composition of dust. The analysis revealed that the dust of various phosphorus plants comprises the same basic components, yet the chemical bonds between them differ. The purpose of this study, conducted in the research laboratory of the Zhambyl Branch of LLP “Kazphosphate” (NDFZ) is to investigate the possibility of using new toxic dust, as well as the toxic dust from storage tanks to obtain NPK fertilisers. The study comprises three stages of investigating the oxidation of elementary phosphorus with nitric acid, since elementary yellow phosphorus is dangerous for the environment. As a result of the 1st stage of the study, it was found that toxic dust oxidised with nitric acid cannot be used as a fertiliser, since a non-technological mass is generated, such as acid resin, which is not suitable for drying and granulation. To neutralise the acid reaction mass, it was decided to use an aqueous solution of ammonia, thereby increasing the nutrient content and obtaining a complex NPK fertiliser. In the course of the study, the authors found in the 2nd and 3nd stages of the experiment that to obtain a productsuitable for fertilisation, it is necessary to strictly control the content of elemental phosphorus in the initial toxic dust and adjust the consumption of nitric acid based on its results

The Role of Flavonoids in Invasion Strategy of Solidago canadensis L.

This study provides data on the problem of potential complexation of phenolic compounds synthesized by the plants Solidago canadensis L. and Solidago gigantea Ait. with ammonium forms of nitrogen, partly immobilized in the soil. A comparative analysis of secondary metabolites of the studied plants was performed by HPLC. The leaves of invasively active Solidago canadensis contain nine times more rutin than the plants of Solidago gigantea. Adding to the leaf extracts (v/v1/20) aqueous ammonia solution to pH 8.0 on the chromatograms decreases the intensity or completely causes peaks of flavonoids to disappear; instead, there are peaks of new polar substances (tR 1.5 and 2.0 min). The selective effect of the phenol-ammonium complex on various plant species was revealed. At a concentration of 20 μg/mL, these substances stimulated the formation of lateral roots in soybean seedlings and chrysanthemum cuttings. The suppression of root growth in radish seedlings occurred at a concentration of flavonoids in the extract of 25 μg/mL. In addition, a positive chemotaxis of the Pseudomonas putida (PGPR) was detected in the nitrogen-containing complex based on rutin (5 μg/mL). The identified feature allows PGPR colonization of the root system of Solidago canadensis with corresponding changes in the structure of the microbial community. The ability of the obtained nitrogen-containing polar complexes to regulate the growth processes of plants at extremely low concentration points to promising research in this direction.

Estimation of the Filled Two-Component Cold Curing Polymer System Performance as a Coating for Protecting Concrete Surfaces from the Aggressive Environment Exposure

A filled two-component polymer cold curingsystem (FTCPS) is discussed in the article. To assess its corrosion resistance and durability, the indexes of reagent resistance were determined in accordance with the sorption method. What is optimal, since this value depends on the parameters of mass transfer, the intensity of the reaction, the size of the product, the duration of exposure to aggressive media and other factors. As aggressive media were taken: water, 5% hydrochloric acid solution, 25% aqueous ammonia solution, 10% sodium hydroxide solution, saturated sodium chloride solution. The exposure time was 360 days. Reagent resistance evaluation of the developed FTCPScompositionswas carried out on the basis of guidelines for determining the anticorrosive properties of protective coatings of concrete and laboratory test methods. Changes in the mass of the samples and their reagent resistance as a result of exposure to chemical reagents simulating an aggressive environment during operation were evaluated. The change in the index of reagent resistance in laboratory conditions did not go beyond the value of 0.80, which makes it possible to ensure reliable protection and operation of polymer-coated products under conditions of exposure to these aggressive environments.

Ammonia-vapour-induced two-layer transformation of mesoporous silica coatings on various substrates

We prepared mesoporous silica layers by sol-gel dip-coating technique on various substrates (silicon, polycarbonate, microscope glass and quartz) with the aid of a pore-forming triblock copolymer (Pluronic PE10500). The freshly deposited layers were aged in an aqueous ammonia solution atmosphere. Two types of thermal curing were implemented depending on the substrates: a low-temperature heat treatment at 120 °C for 13 hours or a high-temperature heat treatment at 480 °C for 1 hour. We carried out the porogen extraction of the copolymer molecules from the low-temperature heat-treated samples in a water washing step.Optical spectroscopy measurements gave evidence of a significantly improved and long-lasting light transmission of coatings. The maximum light transmission was 98.3% on glass and 97.6% on polycarbonate after 4 years of storage. TEM investigations showed thin layers with distorted face centred cubic structure.Spectroscopic ellipsometry and ellipsometric porosimetry studies showed a “two-layer” structure. The applied synthesis technique promoted the formation of a double layer structure with relatively thick (10–25 nm) pore sizes. The pseudomorphic transformation rearranged the silica/copolymer structure in presence of ammonia. The transformation was incomplete and resulted in a low porosity (23–34%) upper-layer and a high porosity (40–76%) lower-layer.

Statistical optimization of aqueous ammonia pretreatment and enzymatic hydrolysis of corn cob powder for enhancing sugars production

Response surface methodology (RSM) was applied to systematic optimization of aqueous ammonia pretreatment and enzymatic hydrolysis of corn cob powder (CCP) using self production cellulases from Aspergillus niger HQ-1. Significant variables including aqueous ammonia concentration, temperature and time during pretreatment were screened and optimized. Results showed that CCP with 0.3 mm of particle size should be pretreated using 11.6 wt% aqueous ammonia solution with 20.0% (w/v) of solid loading at 71.3 °C for 8.8 h. The optimized pretreatment conditions could result in 97.1% of cellulose recovery, 66.6% of hemicellulose recovery and 75.7% of lignin removal, respectively. Significant variables including enzyme loading, reaction time and biomass loading during enzymatic hydrolysis were also screened and optimized. Maximal reducing sugar (822.31 mg/g dry substrate, mg/gds) and xylose (316.72 mg/gds) could be obtained while the pretreated CCP was hydrolyzed at 50.0 °C, pH 4.8 for 36.6 h with 10.9 FPU/gds (FPU/g dry substrate) of enzyme loading, 6.95% (w/v) of biomass loading and 0.5% (w/v) of Tween-80. The optimized enzymatic hydrolysis conditions could result in 92.1% of holocellulose conversion and 79.3% of hemicellulose conversion, respectively. In addition, results also indicated that the crude cellulases solution containing xylanases from A. niger HQ-1 could be applied to enzymatic hydrolysis of the pretreated CCP.

EFFECT OF PHYSICOCHEMICAL PROPERTIES OF d-METAL OXIDES ON SUNFLOWER OIL TRANSESTERIFICATION

The physicochemical indicators of d-metal oxides (NiO, CuO, MnO, FeO, PbO, ZnO) which are heterogeneous catalysts for the transesterification process of sunflower oil triglycerides by ethanol and butan-1-ol have been determined. The available specific surface area, surface acidity and basicity, as well as the hydrogen potential change of the catalyst suspension in water were determined for the oxides. The available specific surface area of the oxides was determined by titration of their aqueous suspension with a solution of methylene blue with a predetermined concentration. The surface acidity and basicity of the catalysts were determined by back titration of samples treated with an aqueous solution of ammonia and acetic acid, respectively. It was found that all investigated d-metal oxides have a low specific surface area. The value of specific surface area is in the range of 0.6-1.5 m2/g. The surface acidity and basicity of the catalysts is 0.13-0.27 mmol/g and 0.019-0.066 mmol/g, respectively. It is shown that the change in the aqueous suspension hydrogen potential of the investigated catalysts relative to the distilled water pH is maximum for NiO and ZnO and it is 0.6-0.65, while for CuO this change is the smallest and it is only 0.3. The character of the pH change curves and the pH values of the oxides suspension in equilibrium condition indicate the presence of weak acid sites in the studied catalysts. The indicated catalysts characteristics are compared with the results obtained in the transesterification process of sunflower oil triglycerides by ethanol and butan-1-ol. It was found that there is a correlation between the surface acidity of catalyst and the reaction initial rate of triglycerides transesterification by ethanol and butan-1-ol. At the same time, such a correlation is absent for the surface basicity of the catalysts. This is consistent with the data on the catalysis of the triglyceride transesterification reaction only by strong major active sites. It is concluded that the transesterification reaction of sunflower oil triglycerides by ethanol and butan-1-ol occurs predominantly on the weak acid centers of the d-metal oxides.

Synthesis of holmium orthoferrite nanoparticles by the co-precipitation method at high temperature

Holmium orthoferrite HoFeO3 nanoparticles were synthesized by a simple co-precipitation method via the hydrolysis of Ho (III) and Fe (III) cations in boiling water with 5% aqueous ammonia solution. After annealing the precipitate at 750 and 850 °C for 1 hour, the single-phase HoFeO3 product formed with particle size < 50 nm. The synthesized nanopowders are paramagnetic materials with remanent magnetization Mr < 0.01 emu·g-1, the coercive force Hc = 20÷21 Oe, and magnetization Ms ~ 2.73 emu·g-1 at 300 K in a maximum field of 16,000 Oe.

Electrochemically Synthesized Bis(diimino)metal Coordination Nanosheets as Ultrastable Electrocatalysts for Hydrogen Evolution Reaction

Bis(diimino)metal (MDI) nanosheets (M = Ni, Co, Cu) are synthesized within a few minutes on indium tin oxide (ITO), glassy carbon (GC), and carbon paper (CP) by electro-oxidation of an aqueous solution of metal ions, hexaaminobenzene trihydrochloride, and ammonia. Thin films of these materials are firmly immobilized directly on the substrate. Their PXRD patterns are similar to those prepared by chemical oxidation, indicating considerable crystallinity. Electrocatalytic activities of MDIs on GC in hydrogen evolution reaction were investigated using rotating disk voltammetry. NiDI affords the lowest overpotential for HER among known coordination nanosheet (CONASH) catalysts and offers high catalytic robustness.

Advanced configurations for post-combustion CO2 capture processes using an aqueous ammonia solution as absorbent

In this work, we have developed advanced process configurations for solvent-based CO2 capture processes that use aqueous ammonia as absorbent. In total, ten different advanced configuration concepts have been optimized and analysed, aiming at: (i) achieving in spec NH3 emissions in a controlled way; (ii) minimizing capital costs by avoiding redundant process components; (iii) minimizing the energy demand of the capture process by minimizing the requirements of high temperature steam and by maximizing the possibilities for the use of excess heat from the CO2 point source. As a result, we propose a new benchmark configuration for NH3-based capture processes that, with proper tuning of the process operating conditions, allows to minimize the specific energy consumption while enhancing the flexibility of the capture process with respect to the type and to the features of the electricity and steam available at the CO2 point source, at the minimum consumption of chemicals and process water. This new benchmark configuration for NH3-based capture processes is built upon the Chilled Ammonia Process, avoids the formation of solids and includes: (i) a multi-pressure desorber with recycled vapour compression that is able to decrease the high temperature steam requirements for solvent regeneration, i.e. at ca. 140–160 °C, to values as low as 1.1 MJthkgCO2captured−1, (ii) a vacuum integrated stripper for the recuperation of the solvent that is able to use low temperature steam instead, i.e. below 100 °C, and (iii) a flue gas water-wash column that is able to reduce the NH3 concentration in the CO2-depleted flue gas to values below 10 ppmv without the need of an acid-wash column before the stack.

Stable ZnO/SiO2 nano coating on polyester for anti-bacterial, self-cleaning and flame retardant applications

A simple chemical in-situ synthesis method was adapted to prepare silica-supported zinc oxide (ZnO) catalyst on polyester fabric (PET) in alkali conditions. This imparted the durable photo-active ZnO catalyst on the textiles with multi-functional properties under lights and acidic media. Zinc acetate and sodium silicate as two precursors was used in ammonia aqueous solution to form ZnO@SiO2 nanoparticles on PET fabric at 90 °C. The key characterizations of the silica-supported ZnO catalyst on the PET fabric were investigated by X-ray diffraction (XRD), Field Emission Scanning Electron Microscopy (FESEM) comprising mapping images and Energy Dispersive X-ray (EDX) as well as Fourier Transform Infrared (FTIR). The silica-supported ZnO perfectly controlled the size of nanoparticles (NPs), reduced their size around 28.29 nm and also protected from acid solution (pH≅2). Furthermore, silica on ZnO enhanced the photocatalytic activities of the fabric through discoloration of methylene blue stain in short time under both ambient and acidic conditions. ZnO@SiO2 NPs also acted as thermo-catalyst on the fabric due to inherent thermal resistance of Si, considerably increased the anti-dripping properties of PET during burning. In addition, the bacterial reduction of treated fabric with ZnO@SiO2 NPs for Escherichia coli estimated around 100%. Overall, the silica-supported ZnO catalyst improved the thermo and photo catalytic activities of the PET fabric. This renders a promising approach with good potentiality for application in different industries such as filtration, energy and electronic.

Deadly KCN and pricey metal free track for accessing β-ketonitriles employing mild reaction conditions

A one pot synthesis of β-ketonitriles from readily accessible 3-chloropropenals using economically benign iodine, aqueous ammonia and sodium hydroxide solution, employing mild reaction conditions have been described. This report presents a convenient, inexpensive, highly toxic-matter-free and eco-friendly approach for β-ketonitriles.

Single-Crystal Cobalt Phosphide Nanorods as a High-Performance Catalyst for Reductive Amination of Carbonyl Compounds.

The development of metal phosphide catalysts for organic synthesis is still in its early stages. Herein, we report the successful synthesis of single-crystal cobalt phosphide nanorods (Co2P NRs) containing coordinatively unsaturated Co–Co active sites, which serve as a new class of air-stable, highly active, and reusable heterogeneous catalysts for the reductive amination of carbonyl compounds. The Co2P NR catalyst showed high activity for the transformation of a broad range of carbonyl compounds to their corresponding primary amines using an aqueous ammonia solution or ammonium acetate as a green amination reagent at 1 bar of H2 pressure; these conditions are far milder than previously reported. The air stability and high activity of the Co2P NRs is noteworthy, as conventional Co catalysts are air-sensitive (pyrophorous) and show no activity for this transformation under mild conditions. P-alloying is therefore of considerable importance for nanoengineering air-stable and highly active non-noble-metal catalysts for organic synthesis.