Hydrazine Hydrate In Presence Research Articles

Mechanism of highly efficient adsorption of 2-chlorophenol onto ultrasonic graphene materials: Comparison and equilibrium

The deficiencies of the recently reported improved Hummers method for the synthesis of graphene oxide (GO), such as high reaction temperature (60°C) and long reaction time (10h), were successfully solved using a low-intensity ultrasonic bath for 30min at 40°C. Furthermore, compared to its conventional synthesis counterpart, a facile and fast, one-step ultrasonic method that excluded hydrazine hydrate was developed to synthesize reduced GO (rGO) from graphite (10min, 50°C) in the presence of hydrazine hydrate (rGO-C, 12h, 90°C). The adsorption characteristics of 2-chlorophenol (2-CP) from an aqueous solution were investigated using rGOs and GOs prepared by ultrasonic (rGO-Us/GO-Us) and conventional (rGO-C/GO-C) methods. Whereas 2-CP was completely removed with rGO-Us after 50min, only 40% of 2-CP was eliminated with rGO-C. The maximum adsorption capacity of 2-CP calculated by the Langmuir model onto rGO-Us (208.67mg/g) was much higher than that onto GO-Us (134.49mg/g). In addition, the ultrasonic graphene adsorption capacities were much higher than the corresponding values of rGO-C (49.9mg/g) and GO-C (32.06mg/g). The enhanced adsorption for rGO-Us and GO-Us is attributed to their greater surface areas, excellent oxygenated groups for GO-Us and superior π-electron-rich matrix for rGO-Us, compared to other adsorbents. The adsorption of 2-CP on the rGO materials increased with increasing solution pH to a maximum around its pKa (pKa=8.85), while the adsorption for the GO materials increased with decreasing solution pH. The adsorption mechanism proceeded via hydrogen bonding in neutral and acidic media, but via π−π electron donor-accepter (EDA) interactions between 2-CP and graphene materials in basic medium. The FTIR spectrum of GO-Us after adsorption indicates that the position and intensity of many peaks of GO-Us were affected due to the adsorption of different 2-CP groups at different pHs.

Performance characteristics and analysis of tailored Natural Rubber/Organo-kaolin Composites

Natural Rubber/Organo-kaolin composites with mechanical properties tailored to meet specific structural requirements were developed from Natural Rubber and Kaolin intercalates obtained from derivatives of rubber seed oils (Hevea brasiliensis) and tea seed oils (Camellia sinensis). The kaolin intercalation process was achieved in the presence of hydrazine hydrate. Performance characteristics and analysis of the composites were conducted using tensile test, tear resistance test, De-Mattia flex fatigue test and scanning electron microscopy. Modulus of resilience and modulus of toughness were the major performance criteria evaluated in the study. The modulus of toughness were obtained as follows for the composites: Natural Rubber/Tea Seed Oil modified kaolin composites at 6 phr filler loading as 174.54 MPa; Natural Rubber/Rubber seed oil modified kaolin composites at 10 phr filler loading as 107.64 MPa; Natural Rubber/Unmodified kaolin composites at 2 phr filler loading as 67.27 MPa. The most resilient of the composites investigated was found to be Natural Rubber/Unmodified kaolin composites at 10 phr filler loading with a value 54.63 MPa and the least resilient was found to be Natural Rubber/Tea seed oil modified kaolin composites at 10 phr filler loading with a value 0.27 MPa.

ChemInform Abstract: Reductive Homocoupling of Benzylic Halides in Aqueous Medium Using Recyclable Alumina‐Supported Nickel Nanoparticles.

Abstract An economical aqueous protocol for the synthesis of bibenzyls has been developed using easily accessible alumina-supported nickel nanoparticles as a stable recyclable heterogeneous catalyst in the presence of hydrazine hydrate as a co-reductant. Various sensitive moieties like alkoxycarbonyl, methylenedioxy, benzyl, chloro, bromo and nitro were tolerated in the aforesaid method. Besides primary benzylic halides, secondary and tertiary benzylic halides reacted efficiently to furnish the homocoupling products without any elimination.

Facile and controllable one-step fabrication of molecularly imprinted polymer membrane by magnetic field directed self-assembly for electrochemical sensing of glutathione

Based on magnetic field directed self-assembly (MDSA) of the ternary Fe3O4@PANI/rGO nanocomposites, a facile and controllable molecularly imprinted electrochemical sensor (MIES) was fabricated through a one-step approach for detection of glutathione (GSH). The ternary Fe3O4@PANI/rGO nanocomposites were obtained by chemical oxidative polymerization and intercalation of Fe3O4@PANI into the graphene oxide layers via π–π stacking interaction, followed by reduction of graphene oxide in the presence of hydrazine hydrate. In molecular imprinting process, the pre-polymers, including GSH as template molecule, Fe3O4@PANI/rGO nanocomposites as functional monomers and pyrrole as both cross-linker and co-monomer, was assembled through N–H hydrogen bonds and the electrostatic interaction, and then was rapidly oriented onto the surface of MGCE under the magnetic field induction. Subsequently, the electrochemical GSH sensor was formed by electropolymerization. In this work, the ternary Fe3O4@PANI/rGO nanocomposites could not only provide available functionalized sites in the matrix to form hydrogen bond and electrostatic interaction with GSH, but also afford a promoting network for electron transfer. Moreover, the biomimetic sensing membrane could be controlled more conveniently and effectively by adjusting the magnetic field strength. The as-prepared controllable sensor showed good stability and reproducibility for the determination of GSH with the detection limit reaching 3 nmol L−1 (S/N = 3). In addition, the highly sensitive and selective biomimetic sensor has been successfully used for the clinical determination of GSH in biological samples.

Synthesis and characterization of some novel 1,2,4-triazoles, 1,3,4-thiadiazoles and Schiff bases incorporating imidazole moiety as potential antimicrobial agents

(1,4,5-Triphenylimidazol-2-yl-thio)butyric acid hydrazide (3) was obtained via alkylation of 1,4,5-triphenylimidazol-2- thiol (1) with ethylbromobutyrate, followed by addition of hydrazine hydrate. Treatment of acid hydrazide 3 with carbon disulfide in an ethanolic potassium hydroxide solution gave the intermediate potassium dithiocarbazinate salt, which was cyclized to 4-amino-5-[(1,4,5-triphenylimidazol- -2-yl)thiopropyl]-2H-1,2,4-triazole-3-thione (4) in the presence of hydrazine hydrate. Condensation of compound 3 with alkyl/arylisothiocyanate afforded the corresponding 1-[4-(1,4,5-triphenylimidazol-2-ylthio)butanoyl]-4-alkyl/arylthiosemicarbazides (5-7), which upon refluxing with sodium hydroxide, yielded the corresponding 1,2,4-triazole - -3-thiols 8-10. Under acidic conditions, compounds 4-6 were converted to aminothiadiazoles 11-13. Moreover, the series of Schiff bases 14-18 were synthesized from the condensation of compound 3 with different aromatic aldehydes. The newly synthesized compounds were characterized by IR, 1H NMR, 13C NMR and mass spectral analyses. They were also preliminarily screened for their antimicrobial activity.

Preparation of uranium oxides by reductive denitration of uranyl nitrate under microwave heating

Autoclave denitration of solid uranyl nitrate in the presence of hydrazine hydrate at 120°C under the action of microwave radiation (MWR) leads to the formation of uranium dioxide with simultaneous breakdown of excess hydrazine hydrate and nitrate ions. The reaction yields UO2 when performed in an open system in a reducing medium and U3O8 when performed under the conditions of contact with air. Thus, principles have been developed for a new, virtually waste-free procedure for the synthesis of uranium dioxide for the subsequent preparation of oxide nuclear fuel. The procedure is characterized by high rate and considerably reduced power consumption, compared to the similar process performed with convective heating.

Synthesis, structure and thermal properties of a new 1D magnesium sulfoacetate coordination polymer

A new one-dimensional polymeric complex [Mg(SA)(H2O)3], where SA = sulfoacetate, has been synthesised by reaction of Mg(NO3)2·6H2O with sulfoacetic acid in the presence of hydrazine hydrate. The compound was characterized by elemental analysis and FT-IR spectroscopy as well as single-crystal X-ray crystallography. The compound crystallizes in the monoclinic P21/C space group with a = 6.5051(5) A, b = 8.9012(7) A, c = 13.5724(11) A, β = 90.530(2)°, and V = 785.85(11) A3. The crystal structure shows a one-dimensional chain propagated through bridging and chelating a tridentate sulfoacetate anion. Furthermore, the thermal stability of the compound was investigated by thermogravimetry and differential thermal analysis.

Reductive homocoupling of benzylic halides in aqueous medium using recyclable alumina-supported nickel nanoparticles

An economical aqueous protocol for the synthesis of bibenzyls has been developed using easily accessible alumina-supported nickel nanoparticles as a stable recyclable heterogeneous catalyst in the presence of hydrazine hydrate as a co-reductant. Various sensitive moieties like alkoxycarbonyl, methylenedioxy, benzyl, chloro, bromo and nitro were tolerated in the aforesaid method. Besides primary benzylic halides, secondary and tertiary benzylic halides reacted efficiently to furnish the homocoupling products without any elimination.

Synthesis and Characterization of New Polyureas with Improved Thermal Stability from a Novel Ether Keto Diamine

ABSTRACTA novel diamine monomer was prepared in three steps: first, a nucleophilic substitution reaction between hydroquinone and 1‐flouro‐4‐nitrobenzene afforded a nitro compound. Second, the nitro group of this compound was converted to an amino group via reduction in the presence of hydrazine hydrate. In the last step, the reaction of this compound with 4,4'‐diflouro benzophenone led to the synthesis of a novel ether keto diamine. Characterization of all materials was carried out by conventional spectroscopic methods and elemental analysis. A series of new polyureas was prepared via the polymerization reaction of the synthesized diamine with three commercially available diisocyanates including 4,4'‐diphenylmethan diisocyanate, toluene‐2,4‐diisocyanate, and isophoronediisocyanate in N‐methyl‐2‐pyrrolidone. The resulted polyureas were characterized by infrared spectroscopy and elemental analysis. The inherent viscosities of these polyureas ranged from 0.59 to 0.62 dL/g measured at a concentration of 0.5 g/dL. The resulting polyureas were soluble in dipolar aprotic solvents. The thermal properties of the polymers were investigated by differential scanning calorimetry and thermogravimetric analysis. The results indicated that their glass transition temperature values were between 171 and 198°C and at the 10% weight loss of polymers, glass transition temperature was about 325–368°C showing improved thermal stability in comparison with common polyureas. Thermal stability features of the polyurea were also confirmed by means of the pyrolysis‐gas chromatography/mass spectrometry method.

Synthesis of graphene nanosheets via chemical reduction of graphite oxide and application in the adsorption

In the paper graphene was prepared by redox method. The crucial factors affecting the synthesis of graphite oxide was optimized by orthogonal experiment. The colloidal form of graphene was subsequently prepared in the presence of hydrazine hydrate. The factors affecting reduction degree of graphene were discussed, such as hydrazine hydrate dosage and reaction temperature in the system. The obtained grapheme is tested on adsorption performances towards copper, cobalt and other inorganic ions.

Highly-sensitive colorimetric detection of H2O2 based on the Pt@Te nanorods

Te nanorods (NRs) were prepared from TeO2 in the presence of hydrazine hydrate without using any surfactants under ambient conditions. Te NRs were then used as sacrificial templates to prepare Pt@Te NRs by spontaneous redox galvanic replacement between Te and Pt ions. The as-synthesized Pt@Te NRs exhibit a strong catalytic activity for the colorimetric detection of H2O2 using 2, 2′-azino-bis (3-ethylbenzo-thiazoline-6-sulfonic acid) diammonium salt (ABTS) as an indicator.

Microwave assisted synthesis of some new coumarin-pyrazoline hybrids and their antimicrobial activity

A series of pyrazolines 4a-g have been synthesized by Michael addition of chalcones 3a-g with hydrazine hydrate in presence of sodium acetate under conventional heating and microwave irradiation. Structures of the newly synthesized chalcones 3a-g and pyrazolines 4a-g have been established on the basis of IR, 1H & 13C NMR and mass spectral data. All the synthesized compounds were screened for their antimicrobial activity. Some of the compounds shown very good activity compared to standard drugs against all pathogenic bacteria and fungi.

Steroidal pyrazolines and pyrazoles as potential 5α-reductase inhibitors: Synthesis and biological evaluation

Taking pregnenolone as the starting material, two series of pyrazolinyl and pyrazolyl pregnenolones were synthesized through different routes. The synthesis of the analogs of both series is multistep and proceeds in good overall yields. While the key step in the synthesis of pyrazolinyl pregnenolones is the heterocyclization of benzylidine derivatives (3) in presence of hydrazine hydrate, it is the condensation of 3β-hydroxy-21-hydroxymethylidenepregn-5-en-3β-ol-20-one (5) with phenylhydrazine in the synthesis of pyrazolyl derivatives. Compounds of both the series were tested for their 5α-reductase inhibitory activities. Amongst all the compounds screened for their 5α-reductase inhibitory activities, compound 4b, 4c and 6b were found to be the most active.

A convenient synthesis and preparation of the derivatives of ethyl-6-(8-hydroxyquinolin-5-yl)-3-methylpyridazine-4-carboxylate as antimicrobial agents

Synthesis of ethyl 6-(8-hydroxyquinolin-5-yl)-3-methylpyridazin-4-carboxylate (4) via one-pot three component reaction of ethyl acetoacetate with (8-hydroxyquinolin-5-yl)(oxo) acetaldehyde (2) in the presence of hydrazine hydrate at room temperature in water was described. A new series of heterocyclic moieties such as oxadiazoles, triazoles, pyrazoles and Schiff bases were prepared and characterized. The structures of the newly synthesized compounds were established by elemental and spectral data. The antimicrobial activity of some of the synthesized compounds was examined against two Gram‐positive bacteria, two Gram‐negative bacteria and four fungi. The results showed that the tested compounds exhibited significant to moderate antimicrobial.

Hydrodehalogenation of Halogenated Organic Contaminants from Aqueous Sources by Pd Nanoparticles Dispersed in the Micropores of Pillared Clays Under Transfer Hydrogenation Condition

Palladium nanoparticles dispersed in the micropores of the Al-pillared clay was prepared by chemical reduction of palladium chloride salt. The Al-pillared clay was prepared by insertion of [AlO4Al12(OH)24(H2O)12]7+ clusters into clay interlayer and subsequent thermal activation. The pillared clay supported system (Pd/Al–P) was characterized using XRD, IR, UV–Vis, SEM, TEM and sorptometric technique. The expansion of the interlayer space as a result of pillaring was noted for Pd/Al–P system from the XRD study. The TEM study of the supported system indicated well dispersion of the Pd species with particle size in the range of 5–30 nm. The supported Pd particles were used as an efficient heterogeneous catalyst for the hydrodehalogenation of halogenated organics under hydrogen transfer condition using hydrazine hydrate as hydrogen donating agent. The effect of various reaction parameters such as temperature, time, and nature of support, type of hydrogen transfer agents and functionality of substrate was studied in details. The catalytic study clearly indicated superior catalytic activity of the supported Pd system in presence of hydrazine hydrate as hydrogen donating agent. The Al-pillared clay as support influences the dispersion and catalytic activity of the supported Pd nanoparticles.

Homogeneous dispersion of high-conductive reduced graphene oxide sheets for polymethylmethacrylate nanocomposites

The high cohesive interaction between reduced graphene oxide (RGO) sheets usually makes them difficult to disperse, which limits their utilization in achieving effective hybridization with polymers. We report here a new two-step route for preparing non-aggregated and high-conductive RGO powders. Graphene oxide precursor was first reduced by hydrazine hydrate in presence of a thermal unstable surfactant of cetyltrimethylammonium chloride (CTAC). Then a thermal annealing process under H2/Ar atmosphere was further used to remove the non-conductive CTAC molecules. The prepared RGO powder exhibited an electrical conductivity of 2.23 × 104 S m−1 – about ten times higher than the one (N-RGO) simply reduced by hydrazine hydrate. After incorporating into polymethylmethacrylate with a 5 wt% loading, the composite showed a conductivity of 4.11 S m−1, which was 60 times as high as that of the same composite based on N-RGO powder. The addition and subsequent removal of CTAC molecules is an effective method for preparing non-aggregated and highly conductive graphene powder and obtaining good incorporation into polymer matrices.

A facile novel synthesis of delafossite CuFeO2 powders

P-type transparent conducting oxides copper delafossite CuFeO2 powders have been successfully synthesized by using hydrothermal method. The influence of synthesis conditions on the crystal structure, morphology, optical and magnetic properties was systematically studied using X-ray diffraction, scanning electron microscope (SEM), UV–Vis–NIR scanning spectrophotometer and vibrating sample magnetometer. The results indicated the precipitated precursor at pH value of 12 using 1 M NaOH as a base in the presence of hydrazine hydrate as a reducing agent hydrothermally treated at 280 °C for 96 h was transformed to pure rhombohedral 3R delafossite phase. SEM observations of these powders confirmed their hexagonal like structure. The transmittance of the sample was around 65 %. The optical band gap of delafossite–CuFeO2 sample prepared was 3.5 eV as a visible transparent material. Furthermore, magnetic properties behavior was identified and paramagnetism property was found at a room temperature. The saturation magnetization and coercive force for the pure sample were 1.2 emu/g and 58.35 Oe, respectively.

UO2, NpO2 and PuO2 preparation in aqueous nitrate solutions in the presence of hydrazine hydrate

It was established that heating to 90 °C of nitrate solutions of U, Np and Pu in the presence of hydrazine hydrate results in the formation of hydrated dioxides of these elements. On ignition under inert or reducing conditions in the temperature range of 280–800 °C hydrated uranium dioxide transmogrify into crystalline UO2. On ignition in air atmosphere UO2·nH2O turns into UO3 at 440 °C and into U3O8 at 570–800 °C. It was shown that thermolysis of the solution containing a mixture of uranium, neptunium and plutonium nitrates at 90 °C in the presence of hydrazine hydrate allows one to prepare hydrated dioxides (U, Np, Pu)O2·nH2O which on heating to ~300 °C transmogrify into crystalline product of UO2, NpO2 and PuO2 solid solution. The technique of preparation of solid solutions of U and Pu dioxides is very promising as simple and effective method of production of MOX-fuel for.

An efficient and facile regioselective synthesis of new substituted (E)-1-(3-aryl-7,8-dihydrocinnoline-5(6H)-ylidene)hydrazines and (1E,2E)-1,2-bis(3-aryl-7,8-dihydrocinnoline-5(6H)-ylidene)hydrazines

A study concerning the new substituted cinnoline synthesis is described. The use of a one-pot three-component method allows a simple regioselective and efficient synthesis of cinnoline derivatives via reaction of arylglyoxals with 1,3-cyclohexanedione and dimedone in the presence of hydrazine hydrate.

Preparation of Np, Pu, and U dioxides in nitric acid solutions in the presence of hydrazine hydrate

Heating of nitric acid solutions of Np and Pu (∼90°C) in the presence of hydrazine hydrate (HH) leads to the formation of their hydrated dioxides in solution, transforming into crystalline dioxides at 300°C. Thermolysis of a mixed solution of U, Np, and Pu nitrates under the same conditions initially yields hydrated (U,Np,Pu)O2·nH2O, which on heating in air to ∼300°C transforms into a crystalline solid solution of (U,Np,Pu)O2. This method for stabilization of U dioxide in the presence of Pu in an oxidizing atmosphere can be used for preparing (U,Pu)O2 solid solutions of variable composition. This procedure shows doubtless prospects as a simple, efficient, and relatively low-temperature method for the production of MOX fuel for fast reactors.