G. V. Lagodzinskaya

Synthesis of esters of 3-fluoro-3-nitroacrylic acid

ConclusionsThe reaction of 1,3-difluoro-1,1,3,3-tetranitropropane with alkanols was used for the preparation of alkyl esters of 3-fluoro-3-nitroacrylic acid. 1,3-Difluoro-1,3,3-trinitro-1- propene and 1,3-difluoro-1,3-dinitro-2-alkoxy-1-propene were also isolated as intermediates.

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 pKBH+ and Φe 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.

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.

The slowdown of fast proton exchanges and the1h and1h-14n NMR spectra of hydrazine and its methyl derivatives

1. n nA method was proposed for slowing down rapid proton exchanges in hydrazine and its derivatives. n n n n n2. n nThe parameters of the1H and1H-14N NMR spectra of hydrazine, monomethylhydrazine, and nonsymmetrical dimethylhydrazine, thoroughly freed of ions that catalyze proton exchanges, were determined. n n n n n3. n nProton exchanges in nonsymmetrical dimethylhydrazine, hydrazine, and monomethylhydrazine become slow in the NMR time scale at a hydrozonium ion concentration of ∼10−5, 10−8, and 10−8 M, respectively; the rate constants of proton exchanges in the indicated hydrazines were determined.

Study of the autoassociation in hydrazines by the NMR method

1. n nThe model of associations monomer ⇌ cyclic dimer, proposed earlier for dimethylhydrazines (DMH), is incorrect. n n n n n2. n nAssociation occurs according to the scheme monomer ⇌ cyclic n-mer with n=3 for 1,1-DMH and n=3 and 4 for 1,2-DMH. n n n n n3. n nThe association constants were determined for a number of temperatures, enthalpies and entropies of formation of associates, as well as average values of the hydrogen bond energy for the models considered.

Nitration equilibrium in the meso-erythritol-aqueous nitric acid system

Twelve equilibrium constants have been measured from 16 for sequential-parallel reactions in meso-erythritol nitration to the fully nitrated compound in aqueous HNO3. Free-energy changes during nitration of the aliphatic polyatomic alcohols, glycerol and meso-erythritol, are highest when diprimary dinitrates (NOON) and (NON) are produced.

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.

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.

Is 1,3-dihydroxypropanenitronic acid really stable?

The condensation of nitromethane with paraformaldehyde in the presence of catalytic amounts of KF and tetra-n-butylammonium bromide in a medium of isopropanol does not afford stable 1,3-dihydroxypropanenitronic acid. In the neutralization of 2-nitro-1,3-propanediol sodium salt by anhydrous CF3COOH, 2-nitro-1,3-propanediol and 2-nitro-1-propen-3-ol were identified.

1,3-disubstituted 1,1,5,5-tetranitropentane-3-nitronic acids

Conclusions1.The reaction of salts of 1,1,1,3,5,5,5-hepta- and 1,5-difluoro-1,1,3,5,5-pentanitropentane with trifluoroacetic acid yields 1,1,1,5,5,5-hexa- and 1,5-difluoro-1,1,5,5-tetranitropentane-3-nitronic acids.2.The chemical shifts of the OH protons of 1,5-substituted 1,1,5,5-tetranitro-3-nitronic acids are similar to those of unsubstituted carboxylic acids.3.Fluorination, chlorination, and bromination of 1,1,1,5,5,5-hexa- and 1,5-difluoro-1,1,5,5-tetranitropentane-3-nitronic acids yields the respective 3-halo derivatives.