苯甲酰肼与对硝基苯肼的热稳定性分析

苯甲酰肼和对硝基苯肼在医药、农药、化工及橡胶等领域有着广泛的应用,这两种肼在热作用下会或快或慢地发生分解反应,放出热量,如果发生失控反应,则具有火灾和爆炸的危险。因此,研究这两种肼在热作用下的热分解过程对其安全生产、储存和使用具有重要的指导意义。目前,国际上多采用差热分析（Differential Thermal Analysis,DTA）或差示扫描量热分析（Differential Scanning Calorimeter,DSC）进行试验研究,而DTA和DSC只能对很少量的样品（通常为几毫克）进行测试,并且不能得出试验反应的压力,同时两种方法中不同的程序升温加热速率对物质的热分解特性曲线影响很大,因而测试得到的初始分解温度存在一定的差异。     

A simple Schiff base as selective and sensitive fluorescent-colorimetric hydrazine chemosensor

ABSTRACT

A new fluorescent-colorimetric chemosensor L has been synthesised by Schiff base condensation reaction between 1,8-diaminooctane and 4-nitro-benzaldehyde in very good yields. Its photo-luminescent properties and selective detection properties for hydrazine have been examined. The synthesised chemosensor exhibited highly selective fluorescence on-off response for hydrazine amongst a wide range of different metal cations, anions and amines, along with the bare eye colour change from colourless to yellow based on intermolecular hydrogen-bond interaction. The limit of detection of the chemosensor L was estimated as 9.77 × 10^?8 M or 3.12 × 10^?6 g L^?1 for hydrazine which is extremely below the limit set by the World Health Organization (WHO) and the binding stoichiometry was proposed to be 1 : 2 based on ¹H NMR spectroscopic techniques and the Job’s plot analysis. The proposed sensing mechanism is the hydrogen-bonding interaction which has further been established by Density Functional Theory (Functional Density Theory (DFT)) studies. This recognition feature of sensor L makes it an efficient chemosensor for hydrazine detection in different water samples.     

Adsorption of sarin and chlorosarin onto the Al12N12 and Al12P12 nanoclusters: DFT and TDDFT calculations

This study provides details of the electronic and optical structures and binding energies of sarin (SF) and chlorosarin (SC) with Al–N and Al–P surfaces of Al₁₂N₁₂ and Al₁₂P₁₂ nanoclusters in the gas phase. The adsorption mechanism of SF and SC on these nanoclusters containing the Al³⁺ central cation was studied. Optimized geometries and thermodynamic parameters of SF and SC adsorption complexes were calculated. SF and SC are chemisorbed on these nanoclusters because of the formation of PO···Al bonds. The chemical bond is formed between an oxygen atom of SF and SC and an aluminum atom of fullerene-likes (chemisorption). However, the binding energies of the complexes with the Al₁₂N₁₂ nanocluster are larger than these values for the Al₁₂P₁₂ nanocluster. The interaction enthalpy and Gibbs free energy of all studied systems were found to be negative. We can conclude that SF and SC will be adsorbed preferably on Al₁₂N₁₂ nanocluster.     

Adsorption of Thiophene on Aluminum Nitride Nanotubes

Abstract

Thiophene adsorption on pristine (6,0) aluminum nitride nanotubes was studied by using density functional theory calculations, by means of B3LYP and M06-L functionals. We present the nature of the thiophene interaction in different sites of the nanotube. Adsorption energies corresponding to adsorption of thiophene are calculated to be in the range ?18.90 to ?21.06 kJ mol^{? 1} Pablo, P. C., Liprandi, D. A. and Fígoli, N. S. 1996. Ind. Eng. Chem. Res., 34: 3713–3717. [Web of Science ®] , [Google Scholar]. It has been shown that the thiophene molecule has a weak physical adsorption on the pristine models due to weak Van der Waals interaction between the nanotubes and thiophene molecule. The charge transfer between thiophene and the AlNNT is minimal and the electronic properties of the nanotubes are not affected by the thiophene adsorption. Also, with change of tube type, more efficient binding could not be achieved. The results indicate that transition metal nanoclusters are more suitable catalyst with respect to nontransition metal nanotubes in the petroleum industry.     

Thermal properties of hydrazine in nitric acid solution

Since some combustible, oxidative and reductive chemicals are used in the extracting process in the nuclear reprocessing plant the process has potential hazards of a fire and explosion due to the undesired reaction. In this study to obtain a better understanding of the thermal properties of hydrazine in nitric acid solution which is used for preventing the oxidation of extracted plutonium, thermal analysis was carried out for the mixtures in various conditions. From the results of DSC it was revealed that the vessel material has an influence on the thermal decomposition of hydrazine. It was also found that hydrazine reacted with nitric acid in an autocatalytic manner, and concentration of nitric acid has a strong influence on the thermal hazard of hydrazine and nitric acid mixtures.     

Density-functional calculations of HCN adsorption on the pristine and Si-doped graphynes

Graphyne, a lattice of benzene rings connected by acetylene bonds, is one-atom-thick planar sheet of sp- and sp²-bonded carbons differing from the hybridization of graphene (considered as pure sp²). Here, HCN adsorption on the pristine and Si-doped graphynes was studied using density-functional calculations in terms of geometric, energetic, and electronic properties. It was found that HCN molecule is weakly adsorbed on the pristine graphyne and slightly affects its electronic properties. While, Si-doped graphyne shows high reactivity toward HCN, and, in the most favorable state, the calculated adsorption energy is about ?10.1 kcal/mol. The graphyne, in which sp-carbon was substituted by Si atom, is more favorable for HCN adsorption in comparison with sp²-carbon. It was shown that the electronic properties of Si-doped graphyne are strongly sensitive to the presence of HCN molecule and therefore it may be used in sensor devices.     

Predicting adsorption behavior of Triacanthine anticancer drug with pure B12N12 nano-cage: A theoretical study

Predicting adsorption behavior of the Triacanthine (TRC) anticancer drug on the surface of B₁₂N₁₂ nano-cage was investigated using DFT and TD-DFT methods by B3LYP/6-311+G(d) level in the water solution. The adsorption energies of the TRC-B₁₂N₁₂ complexes (A-C) were shown that the adsorption process is exothermic. The UV/Vis absorption and IR spectra analysis were calculated to investigate the changes happening in adsorption of TRC over nano-cage. According to the results, the interaction of the TRC drug from the N9 atom on the B₁₂N₁₂ nano-cage (model A) has the most chemical stability rather than models B and C. Based on NBO analysis, the charge transfer process has happened between the TRC drug and B₁₂N₁₂ nano-cage. Recovery time, charge difference (ΔN), and ELF analysis were calculated. It was understood that the B₁₂N₁₂ nano-cage can be a good carrier for the delivery of TRC anticancer medicine.     

Thermal hazard analysis of mixed system of hydrazine and nitric acid

In order to obtain a better understanding of the thermal hazard of hydrazine and nitric acid mixtures which are used in plutonium and uranium recovery by extraction (PUREX) process during recycling of spent fuel in nuclear plant, DSC was carried out for the mixed system made by the small scale reaction calorimeter super-CRC in various conditions. It was found that the concentration of the nitric acid has a strong influence on the thermal behavior of the mixed system, and hydrazine nitrate which is formed in the reaction in the mixture was determined by DSC with FTIR analysis.     

A highly selective and sensitive fluorescent turn-on chemosensor for Al3+ based on a chromone Schiff base

A Schiff-base fluorescent sensor, 7-methoxychromone-3-carbaldehyde-(3′,4′-dimethyl)pyrrole hydrazone (MCPH), was synthesized. The new sensor showed high selectivity for Al³⁺ over other metal ions examined in acetonitrile. Upon binding Al³⁺, a significant fluorescence enhancement with a turn-on ratio over 101-fold was triggered. The detection limit of MCPH for Al³⁺ was 2.5?×?10^?7?mol?L^?1.     

分光光度法测定水合肼技术性因素的研究

针对现行肼测定的标准分析方法(水质肼的测定-对二甲氨基苯甲醛分光光度法HJ674-2013)影响测定质量的因素,以实际测定为依据,从分析方法和统计学方法出发,研究和论述了校准曲线的建立、方法的测定范围、被测定样品的取样方式等几个方面,对分析测定及测定结果造成的影响。结果表明,分析方法的校准曲线建立方式会对校准曲线的质量和精密度产生很大影响,最终将影响到样品测定的准确性;测定范围将会影响到方法的适用性;方法中不正确的取样方式,不仅影响到样品测定的准确性,同时也使溯源性受到影响。本文给出的建议,可对方法的应用和修订提供技术支持。     

Determination of hydrazine in polyvinylpyrrolidone by derivatization and square wave voltammetry

A rapid and precise method has been developed for the determination of hydrazine in polyvinylpyrrolidone (PVP). Hydrazine is converted to salicylaldazine by reaction with salicylaldehyde. After extraction, the azine is reduced at –1.56 V versus the SCE at the hanging drop electrode. Detection is accomplished using square wave voltammetry and comparison to an external salicylaldazine standard. The described procedure can detect as little as 70 ng/g hydrazine in PVP.     

Adsorption and deformation phenomena at interaction of N2 and microporous carbon adsorbent

Deformation of activated carbon adsorbent ACC (adsorbent obtained by removing Si from SiC) upon N(2) adsorption has been studied. To solve this problem, a dilatometer was used. Its main part was a line differential transformer, the core of which was connected to the adsorbent by means of a rod. Any changes in the adsorbent height caused a change in the core position in the transformer, which influenced the signal recorded from its secondary winding. These results were compared with the adsorption isotherms. High sensitivity of the dilatometric method has been shown. The dilatometer used allowed the measurement of absolute deformations in the range 1 x 10(-4) to 3 mm.     

A new biosynthesis of CuCo2S4 nanoparticles as a high-performance supercapacitor electrode and excellent non-enzymatic hydrazine sensor

In this work, we report the biosynthesis of CuCo₂S₄ nanoparticles (Bio-NPs) via hydrothermal method. The synthetized Bio-NPs-CuCo₂S₄ was studied as an active material of working electrode for electrochemical supercapacitor and non-enzymatic hydrazine sensor. The Bio.NPs-CuCo₂S₄/ITO electrode has a specific capacitance of 264 F/g at a current density of 1 A/g. Meanwhile, the electrode exhibits excellent electrochemical performances, such as an energy density of 33 Wh/Kg and a power density of 900 W/Kg. The Bio.NPs-CuCo₂S₄/ITO electrode for non-enzymatic hydrazine sensor exhibits a very high sensitivity of 2400 μA.mM⁻¹.cm⁻², a wide linear range from 0.001 to 1.400 mM and shows an excellent selectivity.     

Molecular modeling investigation of adsorption of Zolinza drug on surfaces of the B12N12 and Al12N12 nanocages

Structural Chemistry - In the current work, the adsorption of Zolinza (ZOL) drug on B12N12 and Al12N12 nanocages was investigated using density functional theory (DFT) and time-dependent DFT...     

Thermal hazard analysis of hydrazine and nitric acid mixtures

Summary In order to obtain a better understanding of the thermal hazard of hydrazine and nitric acid mixtures which are used in PUREX (Plutonium and Uranium Recovery by Extraction) process during recycling of spent fuel in nuclear plant, DSC and small scale reaction calorimetry super-CRC were carried out for the mixtures in various conditions. From the DSC analysis the apparent activation energy of hydrazine monohydrate in SUS 303 crucible was determined to be 96 kJ mol^-1. The mixing hazard of hydrazine monohydrate with nitric acid was measured with super-CRC and the results suggested that the concentration and the mass of nitric acid had a strong influence on the mixing heat of reaction of the system.     

Determination of hydrazine and sulphite in the presence of one another

A simple titrimetric method has been developed for determination of sulphite and hydrazine in compounds containing both. The sulphite is oxidized quantitatively to sulphate by iodine in acid medium, and the sum of hydrazine and sulphite is determined by Andrews titration with iodate. The hydrazine content is found by difference.     

C24和B12N12团簇的结构与稳定性

本文采用量子化学密度泛函理论的B3LYP/6-31G*方法,对C24和B12N12团簇的12种异构体进行了优化,并对它们的几何构型、振动频率、核独立化学位移(NICS)和结合能进行了理论探讨, 比较了C24和B12N12团簇结构的稳定性。研究表明:C24团簇的最稳定几何构型为类石墨结构d,B12N12团簇的最稳定结构为4/6笼状结构g。C24异构体的稳定性大小顺序为d > b > f > c > a > e。B12N12团簇异构体稳定性大小顺序为a > f> c> d > e >b。     

肼及其衍生物在固体电极上的直接电化学行为研究

肼及其衍生物被广泛应用于医药,化工,军事,航天等领域,并被用作推进剂,水处理剂,农药,医药,燃料电池,光稳定剂以及化工生产助剂等诸多方面。因此对肼及其衍生物的研究和开发有着极其重要的理论意义和应用价值。本文研究了肼(Hydrzdine,DH),苯肼(Phenylhydrazine,PH),对硝基苯肼(p-Nitrophenykhzille,PNPH)和2,4-二硝基苯肼(2,4-DinitrophenyIhydrazine,DPH)在固体玻碳电极和铂电极上的不可逆电化学氧化行为,     

Synthesis of Ni/Al2O3 catalysts via alkaline polyol method and hydrazine reduction method for the partial oxidation of methane

Nickel catalysts supported on γ-Al₂O₃ were synthesized in the presence of polyvinylpyrrolidone (PVP) using both alkaline polyol method and hydrazine reduction method while fixing the weight ratio of [(PVP)]/[Ni(CH₃COO)₂·4H₂O] at 2. The effects of hydrazine [N₂H₅OH]/[Ni] and [NaOH]/[Ni] molar ratios on the structural properties of the catalysts were characterized by transmission electron microscopy (HRTEM) and by X-ray diffraction (XRD). The average of monodispersed Ni nanoparticles ranged between 8.0 and 13.0 nm. The catalytic tests were performed for the partial oxidation of methane in the temperature range of 600–800 °C under a flow rate of 157,500 L kg^–1 hr^–1 with CH₄/O₂= 2. At the molar ratio of [NaOH]/[Ni] = 2, the resultant nickel nanoparticles on alumina was established completely without impurities; thus, it demonstrated the highest catalytic activity, 88% for CH₄ conversion, and H₂ selectivity, 90.60%. The optimum [N₂H₅OH]/[Ni] ratio was determined as 4.1, which means a good catalytic performance and 89.35% selectivity to H₂ for the partial oxidation of methane.