Hydrazine redox reactions

Joining two heteroatoms to a ring by radical combination is not presently a common route to heterocycles. It might become more important if the art of metal-catalyzed redox reactions keeps advancing at the present pace. Current examples are the conversion of 1,5-dithiols to 1,2-dithiepanes by oxidants such as FeCla, and the oxidation of 1,3-propane-bis-hydrazines to 1,2,3,4-tetrazepines (Sections 5.18.4.1 and 5.18.10.1). 

Household ammonia should never be mixed with chlorine bleach, because a redox reaction occurs that generates toxic chlorine gas and hydrazine NH3 + OCl —> CI2 + N2 H4 (unbalanced) Balance this equation. 

Whether nitrogen is in the reduced form (ammonia, ammonium salts, hydrazine) or the oxidised form (nitrites, nitrates), sodium gives rise to dangerous interactions. With the first set of compounds metalation occurs with formation of unstable or highly reducing compounds, whilst, with the second, redox reactions occur. 

See Dibenzoyl peroxide Lithium tetrahydroaluminate Hydrazine Oxidants REDOX REACTIONS ROCKET PROPELLANTS... 

A reaction mixture in aqueous methanol exploded violently at —65°C. (Hydrazine-perchloryl fluoride redox reaction ) A previous reaction at 20°C had been uneventful, and the low-temperature explosion could not be reproduced. 

The reactions of azofurazans have been used to obtain the hydrazine and the amino derivatives. For example, reactions of azofurazans, including macrocyclic azofurazan 196, with BunLi and the lithium derivatives of methylfur-azans were studied. Several competitive processes were found to occur (1) the addition of a Li reagent at the N=N bond (2) the redox reaction giving rise to hydrazofurazans and (3) the reaction of the side chain of azofurazan (Scheme 44) <2004RCB615>. 

The redox reactions of hydrazine toward main-group and transition metal oxidants have been reviewed (73). Different stoichiometries have been found, with N2 appearing as the N-containing oxidized product, sometimes accompanied by the formation of NH3 and/or HN3. The mechanisms have been analyzed in terms of the one- or two-electron nature of the oxidants, and imply both outer-and inner-sphere routes, depending on the oxidant. The very reactive, key intermediate, diazene (diimide), N2H2, has been proposed in most of these reactions. 

Ketones can be reduced directly to alkanes by the Wolff-Kishner reduction. In this reduction, the ketone is converted to the hydrazone, which is treated in situ with sodium hydroxide. An internal redox reaction occurs in which the carbon is reduced and the hydrazine is oxidized to nitrogen. The best experimental conditions include the use of NaOH and ediylene glycol as solvent to carry out the reduction. 

The addition of hydrazine has little effect on the neptunium photo-reactions in nitric acid. There is some evidence that it serves as a reductant, but it is not enough to be significant. Experiments are still in progress which should further define the Np redox chemistry in the presence of added reductants but the competition between the various redox reactions involving both solvent and added reagents limits the potential for application to process conditions. 

Some 2-(ribofuranosyl)furans have been converted into pyridazines using the Clauson-Kaas method via the enediones (115) which are cyclized with hydrazine (Scheme 95), but unexpectedly dihydropyridazinones were formed in addition to the pyridazine products, and in the case of the a-ribofuranosyl derivative, the dihydropyridazinone was the major product <83JOC2998). The origin of the latter product type is unknown, but it ought to involve the generation of a 4-oxobutanoic acid precursor, perhaps by a redox reaction of (115). 

Biguanidinium salts (LH)2[Mo204 14(1120)2] [L = 1-phenyl, l-(p-chloro-phenyl), or l-(p-chlorophenyl)-5-isopropylbiguanidine] have been prepared and characterized, " and SCCC MO methods have been used to interpret the magnetic and spectral properties of the [Mo204Cl4(H20) ] ion. The reaction between Cs2[M02O4Cl4(H2O)2] and N2H4 involves the coordination of the hydrazine to the Mo " centres with no subsequent redox reaction. ... 

N2H4 and Derivatives. Interest in the use of hydrazine and its derivatives in quantitative redox reactions continues. Conditions have been developed for a direct potentiometric titration of Fe with hydrazine sulphate at room temperature ... 

Uses Reducing agent corrosion inhibitor wastewater treatment electrolytic plating redox reactions polymerization catalyst organic hydrazine derivs. rocket propellant corrosion inhibitor, oxygen scavenger in boiler... 

Deposition of molybdenum(III)oxide onto a silica support was reahzed at pH = 8.7 at temperatures of 0-60 °C over a wide range of loadings of 1-20 wt% Mo. As can be inferred from Equation 6.7 it is to be expected that a lower pH will favor this redox reaction. Based on this fact a very peculiar phenomenon was noted and exploited. Using silica spheres of 1.5 mm size an impregnation with the aqueous molybdate/hydrazine solution was carried out. It was observed that under certain conditions of concentrations and temperature the deposition of the (brown) Mo compound took place... 

Accordingly, the test involves a redox reaction analogous to that in the tests for hydrazine, hydroxylamine, sodium hydrosulfite, Rongalite, which function as hydrogen donors in alkaline solution. 

Solutions of methylene blue with the cation (I) are not reduced by concentrated hydrazine sulfate solution even at the boiling temperature. If, however, tiny amounts of molybdate are added, the blue color disappears because of a rapid reduction to the leuco compound of the dyestuff, i.e. methylene white containing the cation (II). Accordingly, Mo catalytically hastens the immeasurably slow redox reaction between methylene blue and... 

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