Hydrazine properties

This can be extracted from impure phosphine prepared by the action of sodium hydroxide on phosphorus. Unlike hydrazine, it has no basic properties. It is a powerful reducing agent and burns spontaneously in air, this reaction explaining why impure phosphine containing traces of diphosphane ignites spontaneously in air. 

Hydrazinoselenazoles are solids, often in the form of crystals. They possess the characteristic properties common to hydrazines, especially as... 

The many advantageous properties of hydrazine ensure continued commercial utility. Hydrazine is available in anhydrous form as well as aqueous solutions, typically 35, 51.2, 54.4, and 64 wt % N2H4 (54.7, 80, 85, and 100% hydrazine hydrate). 

The freezing point diagram for the hydrazine—water system (Eig. 1) shows two low melting eutectics and a compound at 64 wt % hydrazine having a melting point of —51.6°C. The latter corresponds to hydrazine hydrate [7803-57-8] which has a 1 1 molar ratio of hydrazine to water. The anomalous behavior of certain physical properties such as viscosity and density at the hydrate composition indicates that the hydrate exists both in the Hquid as well as in the soHd phase. In the vapor phase, hydrazine hydrate partially dissociates. 

Table 1 summarizes some of the physical properties of anhydrous hydrazine, hydrazine hydrate, monomethyUiydrazine, and unsymmetrical dimethyUiydrazine (6—8). A comprehensive review of the physical and thermodynamic properties of the hydrazines is available (9). 

Heterocyclics. One of the most characteristic and useful properties of hydrazine and its derivatives is the ability to form heterocycHc compounds. Numerous pharmaceuticals, pesticides, explosives, and dyes are based on these rings. A review of the appHcation of hydrazine in the synthesis of heterocychcs is available (91). For further information in the field of heterocycHc chemistry, see the General References. 

Monoamine—Oxidase Inhibitors. In the mid-1950s, tuberculosis patients with depression being treated with iproniazid (42) were occasionally reported to become euphoric. This observation led to the discovery of irreversible monoamine—oxidase (MAO) inhibiting properties. Hydrazine and nonhydrazine-related MAO inhibitors were subsequentiy shown to be antidepressants (122). Three other clinically effective irreversible MAO inhibitors have been approved for treatment of major depression phenelzine (43), isocarboxazid (44), and tranylcypromine (45). 

Nitrogen forms more than 20 binaiy compounds with hydrogen of which ammonia (NH3, p. 420), hydrazine (N2H4, p. 427) and hydrogen azide (N3H, p. 432) are by far the most important. Hydroxylamine, NH2(OH), is closely related in structure and properties to both ammonia, NH2(H), and hydrazine, NH2(NH2) and it will be convenient to discuss this compound in the present section also (p. 431). Several protonated cationic species such as NH4+, N2H5+, etc, and deprotonated anionic species such as NH2 , N2H3 , etc. also exist but ammonium hydride, NH5, is unknown. Among... 

Table 11.3 Some physical and thermochemical properties of hydrazine...

E. W. Schmidt, Hydrazine and its Derivatives, Prepa-ration. Properties, Application Wiley, Chichester, 1984,... 

The free acid is monobasic, pA 3.85 it is much more easily hydrolysed than sulfamic acid and has reducing properties comparable with those of hydrazine. Like sulfamic acid it exists as a zwitterion in the solid state H3NNHS03. ... 

The free selenazole hydrazines are solids, sometimes well crystallized compounds. They show the typical properties of hydrazines. Thus they reduce Fehling s solution on warming and liberate silver, even in the cold, from ammoniacal silver nitrate solution. Further, they react with carbonyl compounds for example, benzylidene hydrazones are formed with benzaldehyde. These are identical with the hydrazones formed by direct condensation from benzaldehyde selenosemicarbazone and the corresponding a-halogenocarbonyl compound. 2-Hydrazino-4-phenylselenazole has also been reacted with acetophenone. The 2-a-methylbenzylidenehydrazone of 4-phenyl-selenazole (2, K = CJl, R" = H, R" = NH—N CMe-aH ) forms golden yellow plates mp 171°C. ... 

Heat of vaporization, 66 see also Vaporization Helium, 91 boiling point, 63 heat of vaporization, 105 interaction between atoms, 277 ionization energy, 268 molar volume, 60 on Sun, 447 source, 91 Hematite, 404 Hemin, structure of, 397 Hess s Law, 111 Heterogeneous, 70 systems and reaction rate, 126 n-Hexane properties, 341 Hibernation, 2 Hildebrand, Joel H.. 163 Holmium, properties, 412 Homogeneous, 70 systems and reaction rate, 126 Hydration, 313 Hydrazine, 46, 47, 231 Hydrides of third-row elements, 102 boiling point of. 315 Hydrocarbons, 340 unsaturated, 342... 

The catalytic activity of PCSs results from their semiconductor properties. The first studies in this field date from 1959—1961. Thus, we have demonstrated catalytic activity of products of the thermal transformation of PAN in the decomposition reactions of hydrogen peroxide, hydrazine hydrate, and formic acid270, 271. There is an indication of catalytic activity of poly(aminoquinone) in the reactions of the hydrogen peroxide decomposition272. ... 

Surface-acting properties, of process contaminants 550 Surface adsorption reaction, of hydrazine 492... 

Its physical properties are very similar to those of water for instance, its melting point is f.5°C and its boiling point is 113°C. However, its chemical properties are very different. It is dangerously explosive and is normally stored and used in aqueous solution. Hydrazine is used as a rocket fuel and to eliminate dissolved, corrosive oxygen from the water used in high-pressure, high-temperature steam furnaces ... 

The hydrazines of quinoxaline aldehydes and ketones are so closely akin to regular hydrazinoquinoxalines that all are included in this section. The NMR properties of such hydrazine derivatives have been studied. ... 

In this study, the chemical reduction in aqueous solution using conventional and ultTMonic hydrothermal reduction method were conducted for the preparation of fine nickel powders from the aqueous solution of nickel salt by reducing with hydrazine. The differences in the reaction parametera and final product properties resulting from two methods were identified to find the effects of ultrasound. 

The optical properties of electrodeposited, polycrystalline CdTe have been found to be similar to those of single-crystal CdTe [257]. In 1982, Fulop et al. [258] reported the development of metal junction solar cells of high efficiency using thin film (4 p,m) n-type CdTe as absorber, electrodeposited from a typical acidic aqueous solution on metallic substrate (Cu, steel, Ni) and annealed in air at 300 °C. The cells were constructed using a Schottky barrier rectifying junction at the front surface (vacuum-deposited Au, Ni) and a (electrodeposited) Cd ohmic contact at the back. Passivation of the top surface (treatment with KOH and hydrazine) was seen to improve the photovoltaic properties of the rectifying junction. The best fabricated cell comprised an efficiency of 8.6% (AMI), open-circuit voltage of 0.723 V, short-circuit current of 18.7 mA cm, and a fill factor of 0.64. 

Hydrazine combusts spontaneously In contact with dinitrogen tetroxide. As with nitric acid, this property made it suitable as a propellant for rockets from the N2O4/N2NNH2 system. 

Particularly violent interactions took place between this oxide and hydrazine or hydroxylamine. In fact, the danger is linked to the extreme in-stability and the highly reducing property of these nitrogenous compounds. 

Hydrazine is hardiy stabie (see on p.166). Stabiiity increases with the substitution degree and the hydrocarbon group size. The tabie beiow iiiustrates this typicai property. 

If an unknown compound gives a positive test with the 2 4-dinitrophenyl-hydrazine reagent, it then becomes necessary to decide whether it is an aldehyde or a ketone. Although the dimedone reagent (Section 111,70,2) reacts only with aldehydes, it is hardly satisfactory for routine use In class reactions. It is much simpler to make use of three other reagents given below, the preparation and properties of which have already been described (Section 111,70). 

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