Hydrazine In Solution Research Articles

Application of the 50% Hydrazine Solution Method for O-Glycans Release, their Chemical Labeling, and HPLC Separation

ABSTRACTMucins are high molecular mass glycoproteins with oligosaccharides O-bonded to the protein core. β-elimination is the most popular method used for releasing of O-glycans. However to such released glycoforms it is difficult to introduce a label to amplify a signal for oligosaccharide detection.In our study we used a combination of the β-elimination and hydrazinolysis methods. Released glycoforms were labeled with para-amino benzooic acid ethyl ester (ABBE) and fractionated on HPLC column.This combined procedure seems to be a good tool for O-glycans analysis.

Preparation of Gold−Tellurium Hybrid Nanomaterials for Surface-Enhanced Raman Spectroscopy

We report a simple method for preparing three different SERS-active substrates. Concentrated hydrazine solution as the reducing agent and tellurium dioxide as the precursor were used to prepare Te nanowires (NWs). The as-prepared Te NWs have an average length of 547.7 +/- 111.6 nm and an average width of 15.1 +/- 2.7 nm. Through the reaction of Te NWs with sodium tetrachloroaurate in the presence of hexadecyltrimethylammonium bromide (CTAB) over reaction times of 10, 20, and 60 min, gold-tellurium nanodumbbells, gold-tellurium nanopeapods, and gold pearl-necklace nanomaterials (Au PNNs) were obtained, respectively. By controlling the reaction time, the distance between adjacent gold nanoparticles (Au NPs) in each Te nanowire was tunable, allowing us to investigate its effect on the SERS signals. Having shorter distances among Au NPs (greater electromagnetic fields), the Au PNNs provided a reproducible enhancement factor of 5.6 x 10(9).

Preparation of Fluorescent Tellurium Nanowires at Room Temperature

We have demonstrated a simple approach to the synthesis of fluorescent trigonal tellurium (t-Te) nanowires in aqueous solution at room temperature. The t-Te nanowires were prepared from the reduction of tellurium dioxide (TeO2) with concentrated hydrazine solution through deposition of Te atoms that were reduced from telluride ions (Te2−) and dissolved from amorphous tellurium (a-Te) nanoparticles onto t-Te nanocrystallines. By carefully controlling the growth time from 40 to 120 min, we prepared different sizes of t-Te nanowires; the length changed from 251 to 879 nm, while the diameter only grew from 8 to 19 nm. The absorption wavelength against the diameter of t-Te nanowires displays the diameter dependence of band I (<300 nm). On the other hand, the absorption wavelength against the length of t-Te nanowires displays the length dependence of band II (>600 nm). By increasing the size of t-Te nanowires, their absorption is under a red shift. For example, the maximum wavelengths of the absorption bands for the t-Te nanowires with the lengths of 251 nm are 271 and 602 nm, while those for 879 nm t-Te nanowires are at 280 and 687 nm, respectively. Deconvolution of the photoluminescence profile for t-Te nanowires obtained at 120 min yields four Gaussian peaks centered at 334, 397, 460, and 507 nm.

Reactivity of platinum nanoaggregates in catalytic reduction of U(VI) with hydrazine in acid solutions

Catalysts Pt/SiO2 with different size of Pt nanoaggregates were studied in catalytic reduction of U(VI) with hydrazine in solutions of H2SO4, HClO4, and HNO3. The catalytic activity of the surface Pt atoms of Pt/SiO2 in this reaction monotonically increases with an increase in the size of metal crystallites on the support, i.e., the negative size effect is observed. Catalytic reduction of U(VI) with hydrazine in H2SO4 solutions is significantly faster than in HClO4 and HNO3, and in HClO4 it is slightly faster than in HNO3. The results were interpreted within the framework of the concept of the energetic nonuniformity of the surface atoms and of the mechanisms of catalytic reduction of U(VI) with hydrazine in acid solutions.

Bismuth hexacyanoferrate-modified carbon ceramic electrodes prepared by electrochemical deposition and its electrocatalytic activity towards oxidation of hydrazine

A new bismuth hexacyanoferrate (BiHCF) modified carbon ceramic electrodes (CCEs) fabricated by electrodeposition was reported for the first time. The electrochemical behavior of the resulting modified electrodes was investigated by cyclic voltammetry. The BiHCF-modified CCEs presented good electrocatalytic activity toward the oxidation of hydrazine at a reduced overpotential and was used for amperometric detection of hydrazine. The diffusion coefficient ( D) of hydrazine in solution and the catalytic rate constant ( k cat) were also calculated by chronoamperometric experiments. In addition, the present modified electrode exhibited the advantages of simple preparation, fast response, good stability and reproducibility for hydrazine determination.

Preparation of Cu2O Hollow Nanospheres under Reflux Conditions

AbstractCuprous oxide hollow nanospheres were prepared by heating a solution of copper acetate and hydrazine as a reductant in 2‐propanol at reflux. The size distribution of the nanospheres is mainly in the range 100–200 nm. The products were characterized by X‐ray diffraction, UV/Vis diffuse reflectance spectroscopy, SEM, and TEM. The results indicated that the Cu2O hollow nanospheres aggregated from small nanoparticles with an average size of ca. 6.6 nm. The UV/Vis diffuse reflectance spectrum indicated that the optical absorption edge of the hollow Cu2O nanospheres is redshifted relative to their solid counterparts. The influence of the reaction conditions, such as reaction temperature, reaction time, and the amount of water, on the formation of the nanospheres as well as their morphology were studied. (© Wiley‐VCH Verlag GmbH &amp; Co. KGaA, 69451 Weinheim, Germany, 2007)

Copper patterned polystyrene panels by reducing of surface bound Cu (II)-sulfonyl hydrazide complex

A modified electroless metal deposition method has been developed for copper plating of polystyrene (PS) surfaces. The modified procedure avoids the plasma conditioning and surface activation steps in the classical electroless metal plating process. First step of the present procedure is chlorosulfonation of PS surface by soaking into chlorosulfonic acid, yielding chlorosulfonated surface with density of 0.046–0.110 mmolcm − 2 depending on contact time (10–60 min). In the second step chlorosulfone groups on the surface are converted to sulfonyl hydrazides almost quantitatively by reaction with hydrazine solution (80%). Green Cu (II)-sulfonylhydrazide complex is formed at the surface, in the third step, by interaction with ammoniacle Cu (II) solution at room temperature. The copper in the complex is reduced rapidly in the fourth step, by immersing the specimen into 5% of hydrazine solution. The elemental copper deposited onto the surface serves activating sites to accumulate more (5–7 mg per cm 2) elemental copper from electroless copper solutions in the final step. The present method avoids the surface activation with palladium and allows preparing copper patterns with reasonably high pull-off strengths (3.77 Nmm − 2 ) on PS panels. In the study the copper deposition has been investigated using standard analytical procedures, X-ray photoelectron spectrometry (XPS) and Scanning Electron Microscopy.

Preparation, Electrochemical Behavior and Electrocatalytic Activity of a Copper Hexacyanoferrate Modified Ceramic Carbon Electrode

AbstractA copper hexacyanoferrate modified ceramic carbon electrode (CuHCF/CCE) had been prepared by two‐step sol‐gel technique and characterized using electrochemical methods. The resulting modified electrode showed a pair of well‐defined surface waves in the potential range of 0.40 to 1.0 V with the formal potential of 0.682 V (vs. SCE) in 0.050 mol·dm−3 HOAc‐NaOAc buffer containing 0.30 mol·dm−3 KCl. The charge transfer coefficient (α) and charge transfer rate constant (ks) for the modified electrode were calculated. The electrocatalytic activity of this modified electrode to hydrazine was also investigated, and chronoamperometry was exploited to conveniently determine the diffusion coefficient (D) of hydrazine in solution and the catalytic rate constant (kcat). Finally, hydrazine was determined with amperometry using the resulting modified electrode. The calibration plot for hydrazine determination was linear in 3.0×10−6–7.5×10−4 mol·dm−3 with the detection limit of 8.0×10−7 mol·dm−3. This modified electrode had some advantages over the modified film electrodes constructed by the conventional methods, such as renewable surface, good long‐term stability, excellent catalytic activity and short response time to hydrazine.

Copper-assisted oxidative coupling of primary alcohol and hydrazone: A novel function model of galactose oxidase

Treatments of the MeOH, EtOH and PrOH solutions of 2-acetylpyridine, hydrazine and CuII salts (in molar ratio 2:3:2) afforded respectively the complexes, [CuII(HL)(Cl)](SO3CF3)H2O (1), [CuII(MeL)(H2O)](ClO4)2 (2) and [CuII(EtL)](Cl)](ClO4) (3) (L=bis-(methyl, 2-pyridyl ketone hydrazonyl)methine), in which the ligands, HL, MeL and EtL are formed in situ from oxidative couplings of alcohols and hydrazones.

Tetracyanoquinodimethanide adsorbed on a silica gel modified with titanium oxide for electrocatalytic oxidation of hydrazine

The electrocatalytical oxidation of hydrazine at low potential using tetracyanoquinodimethanide adsorbed on silica modified with titanium oxide was investigated by cyclic voltammetry and amperometry. The modified electrode was prepared modifying a carbon paste electrode employing lithium tetracyanoquinodimethanide adsorbed onto silica gel modified with titanium oxide. This electrode showed an excellent catalytic activity and stability for hydrazine oxidation. With this modified electrode, the oxidation potential of hydrazine was shifted toward less positive value, presenting a peak current much higher than those observed on a bare GC electrode. The linear response range, sensitivity and detection limit were, respectively, 2 up to 100 μmol l−1, 0.36 μA l μmol−1, and 0.60 μmol l−1. The repeatability of the modified electrode evaluated in term of relative standard deviation was 4.2% for 10 measurements of 100 μmol l−1 hydrazine solution. The number of electrons involved in hydrazine oxidation (4), the heterogenous electron transfer rate constant (1.08 × 103 mol−1 l s−1), and diffusion coefficient (5.9 × 10−6 cm2 s−1) were evaluated with a rotating disk electrode.

Electrocatalytic oxidation of hydrazine at o-aminophenol grafted modified glassy carbon electrode: Reusable hydrazine amperometric sensor

Abstract Here, we report a simple and extremely effective method to chemically grafting of o -aminophenol film ( o -AP) onto glassy carbon (GC) electrode by the electrochemical reduction of the corresponding nitrophenyl diazonium salt in acidic aqueous solution for the electrocatalytic detection of hydrazine. The covalently attached o -AP enabled hydrazine to be catalytically oxidized at a greatly reduced overpotential and in a wide operational pH range. A quinoneimine structure has been proposed as the electrocatalytically active species. The kinetics of the reaction between the o -AP mediator and hydrazine has been characterized using cyclic voltammetry, chronoamperometry, and chronocoulometry and rotating disk electrode voltammetry. The o -AP modified electrode as an amperometric sensor has been characterized. The catalytic currents were proportional to the concentration of hydrazine giving rise to calibration curves characterized by two linear segments. The linear segment over the concentration range of 2.0–20.0 μM could be used with analytical purposes to determination of hydrazine with a detection limit of 0.5 μM and a sensitivity of 0.016 μA/μM. The precision of amperometry was found to be 1.7% for replicate determinations ( n = 10) of a 10 μM solution of hydrazine. The resulting modified electrode retains its initial response for at least one month if stored dry in air.

Reduction of Ni2+ by hydrazine in solution for the preparation of nickel nano-particles

The reduction of Ni2+ by hydrazine in solution for the preparation of nickel nano-particles has been studied. It was found that the reactions occur in two stages. The first stage is the reduction of Ni2+ by N2H4 according to 2Ni2+ + N2H4 + 4OH− = 2Ni↓ + N2↑+ 4H2O, while the second stage consists of two side reactions, the decomposition of hydrazine (N2H4 = N2↑ + 2H2↑) and the disproportionation of hydrazine (3N2H4 = N2↑ + 4NH3↑) catalyzed by the formed nickel nano-particles. The reaction for the formation of nickel is also catalyzed by nickel as an autocatalytic reaction. Accordingly, a small amount of inducing agent, NaBH4 can be added to initiate the reaction that can then proceed continuously at 288 K. Kinetic study reveals that the reaction orders with respect to Ni2+, N2H4 and Ni are 1, 0 and 1, respectively. Thus, the increase of the initial concentration of Ni2+ and the amount of inducing agent used accelerate the reaction rate and decrease the consumption of N2H4 significantly. Pure nickel nano-particles with high surface areas are produced and the surface area can increase from 18 to 79 m2/g with the increase of concentration of Ni2+ used. The fully understanding of the reaction between Ni2+ and hydrazine in solution may provide a new optimized technique to prepare the nickel catalysts with high surface areas, in addition to the currently available techniques for the preparation of Raney nickel and supported nickel catalysts.

Electrochemistry and electrocatalytic activity of catechin film on a glassy carbon electrode toward the oxidation of hydrazine

A very stable electroactive film of catechin was electrochemically deposited on the surface of activated glassy carbon electrode. The electrochemical behavior of catechin modified glassy carbon electrode (CMGCE) was extensively studied using cyclic voltammetry. The properties of the electrodeposited films, during preparation under different conditions, and the stability of the deposited film were examined. The charge transfer coefficient (α) and charge transfer rate constant (ks) for catechin deposited film were calculated. It was found that the modified electrode exhibited excellent electrocatalytic activity toward hydrazine oxidation and it also showed a very large decrease in the overpotential for the oxidation of hydrazine. The CMGCE was employed to study electrocatalytic oxidation of hydrazine using cyclic voltammetry, rotating disk voltammetry, chronoamperometry, amperometry and square-wave voltammetry as diagnostic techniques. The catalytic rate constant of the modified electrode for the oxidation of hydrazine was determined by cyclic voltammetry, chronoamperometry and rotating disk voltammetry and was found to be around 10−3 cm s−1 . In the used different voltammetric methods, the plot of the electrocatalytic current versus hydrazine concentration is constituted of two linear segments with different ranges of hydrazine concentration. Furthermore, amperometry in stirred solution exhibits a detection limit of 0.165 μM and the precision of 4.7% for replicate measurements of 40.0 μM solution of hydrazine.

Sonochemical preparation of bimetallic Co/Cu nanoparticles in aqueous solution

Co/Cu bimetallic nanocrystallites, with average diameter of 50 nm, were prepared by a sonochemical method in the hydrazine solution of copper chloride and cobalt chloride. Cobalt was face-centered cubic phase when synthesized and remained fcc phase throughout the annealing process. X-ray diffractometer (XRD), transmission electron microscope (TEM), differential scanning calorimetry (DSC), vibrating sample magnetometry (VSM), inductively coupled plasma-atomic emission spectrometer (ICP-AES) measurements were carried out to investigate their structural and magnetic properties. It was found that the magnetic properties of bimetallic nanocrystallites were close to that of the sputtered alloys.

Reduction of Cr(VI) by hydrazine in solution saturated with KHCO 3

Cr(VI) that exists in many industrial wastes is considered highly toxic. One of the most common ways to dispose of these wastes is to reduce Cr(VI) to Cr(III), which is less toxic and can be easily removed or fixed. Reduction of Cr(VI) by hydrazine in aqueous solutions saturated with potassium bicarbonate was studied in this paper. The content of Cr(VI), molar ratio of hydrazine to Cr(VI) and reaction temperature were 200–1000 ppm, 2:1–10:1 and 25–70 °C, respectively. Results showed that the overall reaction was third-order, i.e. first-order with respect to hydrazine and second-order with respect to Cr(VI). The apparent empirical activation energy was 75.6 kJ mol −1. The reaction kinetics could be interpreted by a three-step mechanism. Effect of the oxygen in the solution on the reduction of Cr(VI) was negligible.

Cyclization of N,N‐Bis(2‐chloroethyl)methylamine in Aqueous Hydrazine

AbstractFor Abstract see ChemInform Abstract in Full Text.

Preparation of palladium and silver alloy membrane on a porous α-alumina tube via simultaneous electroless plating

Simultaneous deposition of palladium (Pd) and silver (Ag) on the porous α-alumina tube with desired metal ratio was attempted by electroless plating procedure. Seeding of Pd nano-particles on the alumina surface resulted in effective co-deposition of Pd and Ag. Nano-particles of Pd nuclei were uniformly distributed by dip-coating with palladium acetate or [Pd(acac) 2] (acac: acetylacetonato ion) in organic solvents followed by reduction with alkaline hydrazine solution. Simultaneous deposition of Pd and Ag was achieved from the mixed aqueous solution which consists of ethylendiamine- N, N, N′, N′-tetraacetic acid (EDTA), ammonia, hydrazine and two metal ion species. The Pd/Ag ratio of the membrane film was controlled in the range of 0–30 wt.% by optimizing the chemical composition of plating solution, particularly with respect to the amount of EDTA, ammonia and hydrazine against the given ratio of Pd and Ag. After simultaneous deposition, alloying of Pd and Ag was successfully achieved under mild conditions, i.e. at 500 °C for 4 h in hydrogen gas atmosphere due to easy inter-diffusion of two metals. Permeation of H 2 and N 2 were measured to evaluate perm-selectivity of the alloy membranes.

Dielectric Relaxation in Aqueous Solutions of Hydrazine and Hydrogen Peroxide: Water Structure Implications

We report dielectric relaxation studies of aqueous solutions of two water-like molecules, hydrazine and hydrogen peroxide, in the neighborhood of their glass transition temperatures, Tg. These solutions behave in a rather simple manner, reminiscent of the diols and diamines of which they are the limiting cases. Their relaxations near Tg are more nearly exponential than in most other cases, and they show essentially no secondary relaxations. Supercooled hydrazine solutions are the more stable. At the composition 20 mol % N2H4, the liquid exhibits precise time−temperature-superposition (TTS) behavior. At higher N2H4 contents, a weak deviation from TTS appears. The temperature dependence of the relaxation time follows the Vogel−Fulcher−Tammann (VFT) equation, and the strength parameter, D, is similar to that of glycerol, a liquid of intermediate fragility. The VFT divergence temperature, T0, lies close to the Kauzmann temperature, TK, determined earlier from calorimetric studies implying that the thermodynamic and kinetic measures of fragility are very similar. Tg values assessed from T(τ=100s) agree well with observed calorimetric, Tg's. Extrapolation of the relaxation time behavior to pure water would imply a Tg for water of 135−140 K; however, the dielectric behavior of amorphous solid water in the temperature range 130−160 K is completely different from that of the solutions showing no sign of the loss peak exhibited by all the solutions. Based on the solution behavior, water controversially must either remain glassy up until the temperature of crystallization or be an almost ideally strong liquid above 136 K. Having shown elsewhere how this implies glassy character up to LDA crystallization and a Tg above 160 K, we now examine the implications for water structure reorganization on dissolution of solutes, certain glycols excepted. It appears that the water in these solutions behaves like ice III rather than ice I.

Cyclization of N,N-Bis(2-chloroethyl)methylamine in Aqueous Hydrazine

1-Amino-4-methylpiperazine (1) is widely used as an intermediate in synthesis of medicinal drugs [1]. Several methods for obtaining it are known. A method based on a two-step scheme has been used industrially, starting from piperazine and followed by its nitrosation and reduction [2, 3]. We have obtained compound 1 for the first time by reaction of N,N-bis(2-chloroethyl)methylamine (2) with an aqueous solution of hydrazine, and we have also developed an efficient method for its isolation. Analysis of the literature [3, 4] allowed us to determine the optimum ratio of the reagents when the dihalo derivative is used as the substrate. In the temperature range 40-50°C, the ratio of the reagents is substrate 1:N2H4 (50%) 1:10. Analysis of the reaction mass using GLC data, chromatography/mass spectrometry, and C NMR showed that along with the target product 1, a number of impurities are formed which we identified.

Simple solution route to uniform MoS 2 particles with randomly stacked layers

MoS 2 particles of uniform size (ca. 70 nm) consisting of random and loosely stacked layers have been synthesized from hydrazine solution with (NH 4) 2Mo 3S 13 as the precursor at 180 °C for 16 h under hydrothermal conditions. The particles were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and high-resolution transmission electron microscopy (HREM). The influences of reaction conditions are discussed while a mechanism is proposed to explain the formation of this peculiar morphology.