Nitromethane, detection

THE STATE OF NITRIC ACID IN INERT ORGANIC SOLVENTS The absence of ions in mixtures of acetic acid and nitric acid is shown by their poor electrical conductivity and the Raman spectra of solutions in acetic acid, nitromethane, and chloroform show only the absorptions of the solvent and molecular nitric acid the bands corresponding to the nitronium and nitrate ions cannot be detected. -... 

The relative abilities of nitromethane, sulpholan, and acetic acid to support the ionisation of nitric acid to nitronium ions are closely similar to their efficiencies as solvents in nitration. Raman spectroscopy showed that for a given concentration of mixed acid (i i nitric and sulphuric acids) the concentration of nitronium ions in these three solvents varied in the order nitromethane > sulpholan > acetic acid. The concentration of mixed acid needed to permit the spectroscopic detection of nitronimn ions was 25 %, 50 % and 60 % in the three solvents, respectively (see 4.4.3). 

A similar circumstance is detectable for nitrations in organic solvents, and has been established for sulpholan, nitromethane, 7-5 % aqueous sulpholan, and 15 % aqueous nitromethane. Nitrations in the two organic solvents are, in some instances, zeroth order in the concentration of the aromatic compound (table 3.2). In these circumstances comparisons with benzene can only be made by the competitive method. In the aqueous organic solvents the reactions are first order in the concentration of the aromatic ( 3.2.3) and comparisons could be made either competitively or by directly measuring the second-order rate constants. Data are given in table 3.6, and compared there with data for nitration in perchloric and sulphuric acids (see table 2.6). Nitration at the encounter rate has been demonstrated in carbon tetrachloride, but less fully explored. ... 

The addition of propylene also led to the increase of NO removal efficiency in a pulsed DBD in a mixture containing N2, 02, NO and 500 ppm C3H6 [30,35], Consequently, the energy cost for NO oxidation decreased from 42 to 25 eV/NO molecule [30], The authors also observed an increase in NO removal up to 30%. The major reaction products detected were carbon oxides, formaldehyde, acetaldehyde, propylene oxide, formic acid, ethyl acetate, methyl nitrate and nitromethane. 

What makes FHF an attractive species to investigate by nmr spectroscopy is that it consists of three nuceli each with spin 1/2 bonded directly. Also, the proton of the strong hydrogen bond should have an unusual chemical shift. Early work failed to detect the expected F doublet and H triplets (e.g. Soriano et al., 1969), and it was not until the importance of the solvent was appreciated that coupling was observed (Fujiwara and Martin, 1971, 1974a,b). Suitable media were found to be the dipolar aprotic solvents acetonitrile, nitromethane and dimethylformamide. 

For the model Henry reaction between benzaldehyde and nitromethane a solvent dependency of the enantioselectivity was detected (e.g., CH2CI2 6% ee MeOH 49% ee THF 62% ee aU at rt). Under optimized reaction conditions concerning catalyst loading (10 mol% of 131), solvent (TH F), and reaction temperature... 

Nitromethane can be determined in workplace air by adsorbing the air sample on Chromosorb, desorbing with ethyl acetate and analysing by gas chromatography with nitrogen-specific detection (method 2527) (Eller, 1994). 

Nitromethane was administered intraperitoneally (200 mg/kg bw) to male Wistar rats (three months of age) as a 10% solution in olive oil. The effects of nitromethane in the liver were detected only 48 h after administration and included a decrease in NADPH-cytochrome c reductase activity with proliferation of the smooth endoplasmic reticulum. Nitromethane also caused an increase in brain acid proteinase (4 h after injection) and acetylcholine esterase activities (4, 24 and 48 h after injection) (Zitting etal, 1982). 

The infrared (IR) spectra of 1,10-phenanthroline, its hydrate and perchlorate in the region 600-2000 cm-1 have been obtained, and the principal features of the spectra interpreted.66 Further studies on the IR spectra of 1,10-phenanthroline,67-69 substituted 1,10-phenanthrolines,70,71 and 1,7-phenanthroline67 have also been reported. The IR spectrum of 4,7-phenanthroline in the region 650-900 cm-1 has been analyzed, and the C—H out-of-plane deformation frequencies were compared with those of phenanthrene and benzo[/]quinoline.72 The IR spectra of salts of 1,10-phenanthroline have been taken, and the NH vibrations determined.28,73 Infrared spectroscopy has been used to detect water associated with 1,10-phenanthroline and some of its derivatives on extraction into nitromethane from aqueous solution.74 The Raman spectrum of 1,10-phenanthroline has been compared with its IR spectrum.75 Recently, the Raman and IR spectra of all ten isomeric phenanthrolines were measured in solution and solid states, and the spectra were fully discussed.76... 

The above mentioned process of the transformation of compounds should also be possible for the other nitro compounds studied, nitromethane and nitrocyclohexane. However, no aliphatic nitroso compounds (or oximes obtained by isomerisation of the aliphatic nitroso compound) have been detected either in the gas or in the adsorbed phase. This is obviously caused by the easy migration of the a-hydrogen along... 

This product was characterized by its NMR spectrum and also by reaction with HC1 followed by BF3/methanol to yield methylcyanoacetate ester. The reaction occurs readily, and in the absence of detectable amounts of the oxidative addition product of acetonitrile with the iridium complex, [Hlr-(depe)2CH2CN]+. In contrast, neither Rh(depe)2Cl nor Rh(dmpe)2Cl (dmpe = Me2PCH2CH2PMe2) react with C02 in acetonitrile, though Rh(dmpe)2Cl does react with C02 in nitromethane to form the analogous nitro-acetate hydride complex, (57). 

Roberts and his associates (1954) re-examined the nitration of the halobenzenes using fuming nitric acid as the reagent in both acetic anhydride and nitromethane. These workers detected a significant solvent effect on the relative rate. Iodobenzene was nitrated by nitric acid in acetic anhydride at a rate 0.13 times that of benzene, in nitromethane this reagent provided a rate ratio of 0.22. 

The compound is soluble in acetone, chloroform, methylene chloride, and nitromethane. It is insoluble in alkanes and cold water and stable toward water in the cold but gives an acidic solution when boiled with water. The infrared spectrum shows a single band at 2510 cm.-1, about 50 cm.-1 higher wave number than in the monobromo compound. The nB spectrum gives a doublet 18.9 p.p.m. upfield from trimethyl borate Jb-h = 155 Hz. The proton spectrum in methylene chloride shows a sharp singlet at 2.91 p.p.m. downfield from external tetramethylsilane and 0.20 p.p.m. farther downfield than the monobromo compound. Boron-attached hydrogens are not detectable. 

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