Ethyl Nitrite Research Articles

Thermal decomposition of peroxypropionyl nitrate: Kinetics of the formation of nitrogenous products

The Arrhenius expression for reaction 1, CH3CH2COO2NO2→CH3CH2COO2+NO2, has been determined to be k=2×1015 exp (−12800/T)·s−1. The free radical mechanism is the exclusive thermal decomposition mechanism of PPN. The main nitrogenous decomposition products of pure PPN are ethyl nitrate, nitrogen dioxide and methyl nitrate. In the presence of NO, ethyl nitrite is the major organitrogen product.

The photolysis of organic substances under atmospheric conditions with a cylindrical photoreactor using ethyl nitrite and nitrogen dioxide

The first-order rate constants of 8 organic substances were measured using the ethyl nitrite and nitrogen dioxide photolyses and their relative rates with respect to n-hexane rate constant were calculated. These were compared with literature data. Relatively small photolysis rates of alkane and aromatics were shown for our photosystems and the alkenes were rapidly photolyzed. For mixed photooxidation reactions of various organics, it would be reasonable for organics of the group classified by their molecular structures to be discussed on their reactivities with OH radicals.

ChemInform Abstract: Amidinosemicarbazido Derivatives of Pyrazole: Synthesis and Inhibitory Effect on Blood Coagulation and Platelet Aggregation.

AbstractNitrosation of the 5‐aminopyrazoles (I) with ethyl nitrite (II) gives the 4‐nitrosopyrazoles (III) which are treated with diphosgene (IV) to yield the pyrazolo(4,3‐c)‐1,2,5‐oxadiazin‐3‐ones (V).

ChemInform Abstract: A High‐Yield Regiospecific Synthesis of Keto Oximes from Aryl‐Conjugated Ethylenes and Ethyl Nitrite in the Presence of Cobalt Complex and BH4‐ Ion.

AbstractTreatment of the styrenes (I) with ethyl nitrite (II) and tetraethylammonium borohydride in the presence of a Co(III) complex yields the ketoximes (III).

A high-yield regiospecific synthesis of keto oximes from aryl-conjugated ethylenes and ethyl nitrite in the presence of cobalt complex and BH4- ion

A high-yield regiospecific synthesis of keto oximes from aryl-conjugated ethylenes and ethyl nitrite in the presence of cobalt complex and BH4- ion

14N Quadrupole Coupling in the Rotational Spectrum of Ethyl Nitrite

We investigated the 14N quadrupole coupling of three rotational isomers of ethyl nitrite in the ground state by microwave Fourier transform spectroscopy. Centrifugal distortion analyses were necessary to assign the transitions with high J quantum numbers. We found an additional splitting of some c-type transitions of the trans-gauche rotamer presumably arising from tunneling through the barrier separating the two equivalent gauche forms. This assumption could not be confirmed yet.

Molecular Beam Study of Ethyl Nitrite Photodissociation and Unimolecular Decay of Ethoxy Fragments

AbstractThe UV photodissociation of ethyl nitrite at excitation wavelenghts of 350, 248 and 193 nm was studied by photofragment translational spectroscopy in a pulsed molecular beam. At all three wavelengths the first dissociation step yields nitric oxide and ethoxy radicals, accompanied by a considerable release of translational energy. At 350 nm the ethoxy radicals are formed with internal energy low enough to be stable under collisionless conditions. At 248 and 193 nm significant fractions of the ethoxy radicals emerge with sufficient internal energy to decay spontaneously into formaldehyde and methyl radicals. At 248 nm a kinematic analysis of the photofragment arrival time distributions is consistent with a sequential dissociation mechanism.

ChemInform Abstract: Synthesis of Masked Glyoxal Monoxime and 1‐Hydroxylaminoacetaldehyde Derivatives.

AbstractThe boron trifluoride‐catalyzed addition of ethyl nitrite (II) to the vinyl ether (I) yields the azo compound (III) which is cleaved on treatment with bases to give an E/Z‐mixtures of the oxime (IVa).

An electron-impact spectroscopy investigation of CH3 and some of its pyrolytic precursors

The electronic spectrum of the methyl radical CH3 was investigated by the technique of variable-angle electron energy-loss spectroscopy. By means of pyrolytic decomposition three possible sources of this radical were tried (tetramethyl tin, ethyl nitrite, and di-t-butyl-peroxide). The spectra of these precursors were obtained. Using di-t-butyl-peroxide, relative differential cross sections for the lowest allowed A″2 3s Rydberg transition in CH3 (5.73 eV) were determined at incident energies of 50 and 25 eV. The behavior of the differential cross section for this band is analogous to that of a spin-allowed transition in a closed shell system and, as expected, in the vicinity of this band no transition of a spin-forbidden nature is detected.

Oxidation of deoxyhemerythrin to semi-methemerythrin by nitrite.

In anaerobic phosphate buffer, pH 6.3-7.5, deoxyhemerythrin is oxidized to semi-methemerythrin (semi-met) by excess sodium nitrite. This oxidation is quantitative as judged by EPR spectroscopy. Further oxidation to methemerythrin is not detected. The absorbance changes of hemerythrin during the oxidation are biphasic. The rate of the faster first phase is linearly dependent on [H+] and [NO2-] suggesting that the oxidant is nitrous acid rather than nitrite. During the slower second phase, the characteristic EPR spectrum of semi-methemerythrin appears. The first phase can be interpreted by a scheme in which nitrous acid transforms deoxyhemerythrin (FeIIFeII) to the semi-met nitrosyl adduct (FeIIFeIIINO) and hydroxide. Independent experiments confirm that the combination of semi-met plus NO produces an EPR-silent adduct. The rates of the absorbance changes for the second phase are nearly independent of nitrite concentration and pH in the range 6.3-7.5. This slower phase involves the transformation of the EPR-silent intermediate to the semi-met nitrite adduct (FeIIFeIIINO2-) and is consistent with rate-limiting dissociation of nitric oxide followed by rapid attachment of nitrite. Nitrite appears to be a unique oxidant of deoxyhemerythrin in that when employed in excess, the final, stable product is semi-met- rather than methemerythrin. The lack of reactivity of ethyl nitrite with deoxyhemerythrin suggests that HONO oxidizes deoxyhemerythrin via an "inner-sphere" process in contrast to oxidants such as Fe(CN)6(3-). A proposed generalization is that excesses of "inner-sphere" oxidants convert deoxy to (semi-met)R, which is stabilized with respect to (semi-met)R, which is stabilized with respect to (semi-met)0 and met because the oxidant and/or a product of the oxidant can bind to the iron site.

Formation of organic nitro-compounds in flowing H2O2+ NO2+ N2+organic vapour systems. Part 1.—Surface initiation efficiency and reactions of ethane

When H2O2 vapour is added to an excess of NO2 in a flow system with ethane as the carrier gas in the presence of a boric-acid-coated surface at temperatures in the range 298–363 K, the organic products are nitroethane, ethyl nitrate and smaller amounts of ethyl nitrite. On the basis of the initiating steps [graphic omitted] the total yield of nitro-compounds, extrapolated to [NO2]= 0, provides a direct measure of the H2O2 to OH conversion efficiency in step (1). This is shown to correspond to that indicated by the previously applied indirect method involving measurement of the variation of CO2 yields with the ratio [S]/[CO] in H2O2+NO2+CO systems containing diethyl ether (S) as the internal kinetic calibrant. This efficiency does not change significantly throughout the above temperature range.The mechanism of formation of the nitrocompounds involves the following competitive steps: [graphic omitted] Arguments are presented that step (8) may proceed by way of partial dissociation of chemically activated C2H5ONO molecules rather than by a bimolecular O-abstraction route.A rate constant of k4=(1.3±0.2)× 1010 dm3 mol–1 s–1 is obtained for the reaction OH + NO2(+ M)→ HNO3(+ M)(4) at ambient temperature for M = C2H6 at a pressure of 40 kPa.

Study of artificial flavouring substances for mutagenicity in the salmonella/microsome, Basc and micronucleus tests

Seventy-six compounds used as artificial flavouring substances in food products were studied for mutagenic properties by the use of the Salmonella/mammalian microsome test (Ames test), Basc test on Drosophila melanogaster and micronucleus test on mouse bone marrow. The following four compounds were mutagenic in Ames tests: ethyl nitrite, ethyl 3-phenylglycidate, 6-methylquinoline and musk ambrette. Of these, ethyl nitrite and musk ambrette also induced a significant (P ⩽ 0.01) increase in sex-linked recessive lethal mutations in Drosophila. Two further compounds, ethyl 3-methyl-3-phenylglycidate and 4-n-propylanisole, appeared weakly mutagenic in Drosophila only. The result with 4-n-propylanisole was judged to be of equivocal biological significance. None of the flavouring substances induced micronuclei, i.e. cytogenetic damage in the bone marrow of mice.

29Si NMR‐untersuchungen an polykieselsäureestern

AbstractLinear and branched siloxanes were prepared by partial hydrolysis of silicon tetrachloride and by esterification of the products of hydrolysation with methyl and ethyl nitrite. 29Si NMR spectra made it possible to distinguish between the isomers of each oligomer up to the heptamer. Linear relationships between the 29Si chemical shifts of the ethyl and the methyl esters on one hand and between the ethyl esters and the poly(silicic acid)s on the other hand were observed. However, due to the different effect of neighboring building units, there are only poor relationships between the 29Si data of the esters and the chloro derivatives.

Ã→X̃ fluorescence spectra of CH 3O and C 2H 5O generated by the Arf laser photolysis of alkyl nitrites

The à → X̃ system fluorescence spectra of CH 3O and C 2H 5O have been obtained following the 193 nm photolysis of methyl and ethyl nitrites. These species are produced in highly rotationally and vibrationally excited states. The OO band is at 31530 cm −1 for CH 3O and at 29200 cm −1 for C 2H 5O. The collision-free fluorescence lifetimes of the à state are independent of the levels of the CO stretching vibrational mode and are measured to be 2.2 μs for CH 3O and 1.8 μs for C 2H 5O. The quenching rate constants by the parent molecules show a little increase with the levels of the CO stretching vibrational mode. The vibrational distribution in the photofragments is discussed using statistical models.

A new method for the synthesis of nitroethane, ethyl nitrite, and ethyl nitrate

When H2O2 vapour and NO2 are mixed in an ethane carrier in a flow system in the presence of a boric acid-coated surface, ethyl nitroethane, and some ethyl nitrite are synthesized; a mechanism is advanced in which OH· and C2H5· radicals are the intermediates.

Oxidation of hemoglobin and myoglobin by alkyl nitrites inhibition by oxygen.

The reactions of human hemoglobin and sperm whale myoglobin with ethyl nitrite under aerobic conditions have been examined in kinetic detail. Ethyl nitrite converts two equivalents of oxyhemoglobin or oxymyoglobin to their oxidized counterparts with concurrent production of one equivalent each of molecular oxygen, nitrate ion, and ethyl alcohol. Inverse first order kinetic dependence on the concentration of molecular oxygen has been observed and is interpreted by a mechanism in which oxygen dissociation from the oxyhemoprotein occurs prior to rate-limiting oxidation by ethyl nitrite. The rate constant for ethyl nitrite oxidation of hemoglobin from which the fourth oxygen has dissociated is calculated to be 45 times greater than the corresponding rate constant for oxidation of deoxyhemoglobin. This rate enhancement is proposed to be a reflection of the oxidative susceptibility of the R and T conformational states of hemoglobin. Results obtained for the oxidation of myoglobin confirm this interpretation as do kinetic data for hemoglobin and myoglobin oxidations by iron(III) and copper(II) complexes. The effects of organic phosphates on rates for hemoglobin oxidations are interpreted in terms of oxidation inhibition by molecular oxygen.

Kinetics and mechanism of the oxidation of human deoxyhemoglobin by nitrites.

The reactions of human hemoglobin with sodium nitrite and ethyl nitrite in deoxygenated media have been examined in kinetic detail. Nitrous acid has been identified from kinetic pH dependence studies as the principal oxidant of hemoglobin in reactions with sodium nitrite. Nitrosylhemoglobin is produced concurrently with methemoglobin as a result of reductive release of nitric oxide from nitrous acid. However, oxidation of hemoglobin by nitric oxide competes with association, and this process is proposed to arise from the action of the nitric oxide dimer on hemoglobin. Ethyl nitrite, which serves as a model for nitrous acid, reacts with hemoglobin at rates that are at least 10 times slower than those extrapolated for nitrous acid, and hydrolysis of the alkyl nitrite is not competitive with oxidation of hemoglobin. The composite experimental results are interpreted to describe alkyl nitrite, and, presumably, nitrous acid association with hemoglobin followed by rate-limiting electron transfer resulting in nitric oxide and alkoxide (or hydroxide) production. Proton transfer resulting in alcohol (or water) formation occurs subsequent to the rate-limiting step as do reactions of hemoglobin with nitric oxide.

NO(A 2∑ +) production by photodissociation of nitrites and of CF 3NO in the 1200 – 1700 Å region

The fluorescence of NO(A 2∑ +), produced by the photodissociation of deuteromethyl nitrite, ethyl nitrite, isopropyl nitrite and trifluoronitrosomethane, was studied using synchroton radiation as the source of excitation in the 1200 – 1700 Å spectral region. The relative quantum yield for NO(A 2∑ +) production at 1400 Å was measured; fluorescence excitation spectra for NO(A, v′ = 0 and v′ = 1) are reported and are compared with the absorption spectra. The results are discussed in terms of a statistical energy distribution among the fragments, with particular emphasis on possible deviation from RRKM predictions in the case of vibrational energy disposal.

Ethyl nitrite. The in vivo synthesis of a mutagenic substance from tobacco smoke and ethanol.

Gas chromatography--mass spectrometry demonstrates the presence of ethyl nitrite in the breath of volunteers subjects who smoke and drink concurrently. The mutagenic compound is quantitated at the ppb level by gas chromatography with the selective electron capture detector. The compound is not detected in cases of only drinking or only smoking.

2- and 4-Pyridones by oxidative demethylation of 2- and 4-methylpyridinium cations

1-Substituted 2- and -4-methylpyridinium cations are converted by pentyl or ethyl nitrite and sodium methoxide into 1-substituted-2- and -4-pyridones respectively.