Nitration of primary aminofurazans with aqueous nitric acid

A convenient procedure for the synthesis of N-nitroaminofurazans by nitration of primary 3-amino-4-R-furazans (R = Me, NO₂, phenyl-, methyl-NNO-azoxy-, tert-butyl-NNO-azoxy-, tert-butyldiazenyl-, etc.) with 66–77% aqueous nitric acid was developed. Depending on the concentration of HNO₃, the reaction is carried out at a temperature from 18 to 55 °C, the yield of the products is 80–99%. 3-Nitramino-4-phenylfurazan with unsubstituted benzene ring was obtained by nitration of 3-amino-4-phenylfurazan.     

Nitration of alkanes with nitric acid by vanadium-substituted polyoxometalates

The nitration of alkanes by using nitric acid as a nitrating agent in acetic acid was efficiently promoted by vanadium-substituted Keggin-type phosphomolybdates such as [H4PVMo11O40], [H5PV2Mo10O40], and [H6PV3Mo9O40] as catalyst precursors. A variety of alkanes including alkylbenzenes were nitrated to the corresponding nitroalkanes as major products in moderate yields with formation of oxygenated products under mild reaction conditions. The carbon--carbon bond cleavage reactions hardly proceeded. ESR, NMR, and IR spectroscopic data show that the vanadium-substituted polyoxometalate, for example, [H4PVMo11O40], decomposes to form free vanadium species and [PMo12O40](3-) Keggin anion. The reaction mechanism involving a radical-chain path is proposed. The polyoxometalates initially abstract the hydrogen of the alkane to form the alkyl radical and the reduced polyoxometalates. The reduced polyoxometalates subsequently react with nitric acid to produce the oxidized form and nitrogen dioxide. This step would be promoted mainly by the phosphomolybdates, [PMo12O40](n-), and the vanadium cations efficiently enhance the activity. The nitrogen dioxide promotes the further formation of nitrogen dioxide and an alkyl radical. The alkyl radical is trapped by nitrogen dioxide to form the corresponding nitroalkane.     

Nitration of aromatic compounds by nitric acid supported on zeolite

Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 8, pp. 1933–1934, August, 1989.     

Nitration equilibrium of water-soluble carboxycellulose

Maximum and minimum values of the equilibrium constants for nitration of hydroxyl groups in water-soluble carboxycellulose (WSCC) have been estimated. Electronegative substituants and elements of the cellulose structure in the WSCC molecule substantially lower the equilibrium constants for nitration compared with those for polyatomic aliphatic alcohols.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 10, pp. 2254–2258, October, 1991.     

Nitration of salts of sulfamides with nitric anhydride

Conclusions The nitration of the sodium salts of sulfamides with nitrogen pentoxide leads to the formation of the corresponding N-nitrosulfamides.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 8, pp. 1804–1806, August, 1971.     

The kinetics of vapor-phase nitration of cellulose 2. Nitration with nitric acid under static conditions

The regularities of vapor-phase nitration of cellulose with HNO₃ under conditions of natural convection and hindered heat removal in the absence of air were studied using the nonisothermal kinetic method. It was established that the nitration rate at the depth of conversion of 0.08 to 0.7 is described by the kinetic law d/dt =k ₁ p/(1+), wherek ₁ = 10^4.49±0.6 exp(–A/RT) s^–1 atm^–1, = 10^{–35.5±15.7}exp(B/RT),A = 36.6±3.8 kl mol^–1, andB = 203±88 kJ mol^–1. The diffusion mechanism of vapor-phase nitration of cellulose, which explains the high value of activation energies, is discussed. The effective diffusion coefficient of HNO₃ in cellulose at 25 °3.7 · 10^–7 cm² s^–1) and the activation energy of diffusion (38.3±4.2 kJ mol^–1) were estimated.For Part 1, see Ref. l.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1981–1985, August, 1996.     

Study of nitration equilibrium in the glycerin-aqueous nitric acid system. 2. Changes in δH and δS in the nitration reaction

The real enthalpies of seven sequential-parallel reactions of nitration of glycerin into glycerin trinitrate were found by combination of the heats of the reactions obtained by the thermochemical method and with the equation for the isobar of the chemical reaction, and the standard enthalpies of formation of glycerin nitrates were calculated with them. The difference in the enthalpies of nitration with respect to different positions in glycerin and its nitrates basically determines the difference in the corresponding equilibrium constants of the nitration reactions.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 8, pp. 1729–1734, August, 1990.     

Nitration of polyhaloalkenes by mixtures of nitric and sulfuric acids

Conclusions The nitration of polyhaloalkenes was carried out under conditions for the complete conversion of nitric acid to the nitronium cation. Butyl esters of -nitrocarboxylic acids were obtained by esterification of the nitration products.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 12, pp. 2814–2815, December, 1985.     

Nitration equilibrium in the glycerol-aqueous-nitric-acid system 3. PMR parameters,conformational structure,and main properties of glycerol and its nitrates

Studies of PMR spectra at a frequency of 294 MHz for glycerol, and its mono-, di-, and trinitrates have been carried out in aqueous solutions of nitric and sulfuric acids and in deuteroacetonitrile. The conformational composition weakly depends on the medium, temperature, and the number of nitrate groups in the molecule. Conformers with CH₂ and OH (or ONO₂) located in a trans position have a certain preference. The basicity parameters pK_BH+ and _e and semiprotonation points of glycerol (separately for primary and secondary hydroxyl) and glycerol dinitrates have been determined. In these properties glycerol and its dinitrates are similar to monatomic alcohols. Acidity functions of solutions of sulfuric and nitric acids were calculated using glycerol and glycerol dinitrates as indicators. Unlike Hammett bases, alcohols in H₂O-H₂SO₄ and H₂O-HNO₃ systems of identical molar composition are protonated practically identically.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 2, pp. 381–389, February, 1991.     

Radiation-induced decomposition of the tributyl phosphate-nitric acid system: Role of nitric acid

Radiation-induced decomposition of tributyl phosphate-nitric acid as a two-component system has been studied. Degradation products, dibutylphosphoric acid (DBP) and monobutylphosphoric acid (MBP), were determined by separation-extraction method. 0.59, 0.78 and 1.38 are the G (DBP) values and 0.15, 0.17 and 0.13 are the G (MBP) values obtained for pure TBP, TBP-3M HNO₃ extract and TBP-5M HNO₃ extract, respectively. G (–HNO₃) values are 5.19 and 6.15 for 3M HNO₃ and 5M HNO₃ extracts. It is shown that nitric acid plays a significant role in enhancing the decomposition of TBP.     

Nitration of 4-halo-1-methylpyrazoles in sulfuric acid

The rate of nitration of 4-bromo- and 4-chloro-1-methylpyrazoles with nitric acid in various concentrations of sulfuric acid is higher at position 5 than at position 3.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1350–1352, October, 1987.     

Study of nitration equilibrium in the glycerin-aqueous nitric acid system. 1. Dependence of the equilibrium constants of nitration reactions on the temperature,acidity of the medium,and structure of the nitrated compound

The equilibrium constants of seven sequential-parallel reactions of conversion of glycerin into glycerin trinitrate in aqueous HNO₃ were measured. The effect of the acidity of the medium on the equilibrium nitration constants is correlated with processes of protonation of glycerin and its nitrates. The equilibrium nitration constants are higher for primary hydroxides than for secondary hydroxides, and they decrease in both series in going from glycerin to its dinitrates.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 8, pp. 1723–1729, August, 1990.     

Nitration in the carbazole series

Nitration of9-tosylcarbazole in acetic anhydride solution gives l-nitro (28%), 2-nitro (19%) and 3-nitro (53%) derivatives. The mixture of the nitro compounds obtained from 9-acetylcarbazole contains 10%, 48% and 42% of the isomers, respectively. Under similar conditions 9-nitrosocarbazole shows a different isomer distribution: 34% of 1-nitro and 66% of 3-nitrocarbazole. Nitration of carbazole is a two step process involving formation and rearrangement of 9-nitrocarbazole. The hypothesis was supported by the results of 1,3,6,8-tetrachlorocarbazole nitration and oxidation of 9-nitrosocarbazole and rearrangement of 9-nitrocarbazole in the nitration conditions.     

Extraction equilibrium of indium(III) from nitric acid solutions by di(2-ethylhexyl)phosphoric acid dissolved in kerosene

The extraction equilibrium of indium(III) from a nitric acid solution using di(2-ethylhexyl) phosphoric acid (D2EHPA) as an acidic extractant of organophosphorus compounds dissolved in kerosene was studied. By graphical and numerical analysis, the compositions of indium-D2EHPA complexes in organic phase and stoichiometry of the extraction reaction were examined. Nitric acid solutions with various indium concentrations at 25 °C were used to obtain the equilibrium constant of InR? in the organic phase. The experimental results showed that the extraction distribution ratios of indium(III) between the organic phase and the aqueous solution increased when either the pH value of the aqueous solution and/or the concentration of the organic phase extractant increased. Finally, the recovery efficiency of indium(III) in nitric acid was measured.