Search

A study of the primary processes in the photolysis of gaseous I-nitropropane at 22°C and 100 ± 1°C is undertaken. 1-Nitropropane undergoes a photochemical reaction giving rise to a six-member complex which produces ethylene, the major photolysis product. This is a typical intramolecular non-radical Norrish Type I1 process and is the most important primary process (1): At higher temperatures homolytic split of C-N bond takes place according to reaction (2), another important primary process: CH,CH,CH,NO, + hv + CH,CH,CHj + NOj. The formation of propylene which is also a major product of photolysis may be the result of the third primary process: CH, CH, CH, NO, + hv + CH3CH=CH, + HONO. The major photolysis products resulting from these processes as identified by GLC and GLC-MS included ethylene, propy-lene and methyl nitrite. The minor products of photolysis were methane, methyl nitrate, ethyl nitrite, ethylene oxide, propyl nitrite, formaldehyde, propionaldehyde, water, nitric oxide and nitrogen d...

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.

Aus [(Me3Si)2N2Li]2SiMe2 (2) entsteht durch Oxidation mit Benzolsulfonylazid bzw. Ethylnitrit ein cyclisches Silyltetrazen (4) bzw. Silylpentazen (6. 4 thermolysiert unter Ringoffnung zu (Me3Si)2NSiMe2N3 (9), 6 unter Ringumlagerung zum Heterocyclus 10a. Die Protolyse mit Trifluoressigsaure fuhrt im Falle von 4 — moglicherweise uber cis-2-Tetrazen — zum Ammoniumazid, im Falle von 6 — moglicherweise uber Pentazen — zu Stickstoff, Ammoniak. Hydrazin und Stickstoffwasserstoffsaure. Preparation and Some Properties of Silyl Derivatives of 2-Tetrazene and -Pentazene (Attempts for the Preparation of cis-2-Tetrazene and -Pentazene) Oxidation of [(Me3Si)2N2Li]2SiMe2 (2) with benzenesulfonyl azide or ethyl nitrite yields a cyclic silyltetrazene (4) and -pentazene (6), respectively. Thermolysis of 4 causes ring opening and formation of (Me3Si)2NSiMe2N3 (9), whereas thermolysis of 6 leads to ring reorganisation with formation of the heterocycle 10a. Protolysis of 4 with trifluoroacetic acid gives ammonium azide — possibly via cis-2-tetrazene —, protolysis of 6 yields nitrogen, ammonia, hydrazine, and hydrazoic acid — possibly via pentazene.

The main primary photochemical process for alkyl nitrites is fission to nitric oxide and alkoxy radicals, a proportion of which may be sufficiently excited to decompose spontaneously. The photolysis of t-butyl, of isopropyl and of ethyl nitrite at 254 nm, in the gas phase, each yields nitrosomethane and an aldehyde or ketone. The overall reaction, in presence of nitric oxide, corresponds to: where R′ and R″ are either H or CH 3 . The dependence of the quantum yield of nitrosomethane and of other products on the pressure of alkyl nitrite, of nitric oxide and of other added gases was investigated to seek confirmation of the excited alkoxy mechanism, to determine primary yield and to obtain information about the deactivation of excited radicals. The results for t-butyl nitrite fully confirm the excited alkoxy mechanism. A value of 0.87 is derived for the quantum yield of t-butoxy radicals sufficiently excited to undergo decomposition, in excellent agreement with a previous estimate. The results for ethyl nitrite also support the excited alkoxy mechanism, with the quantum yield of excited ethoxy radicals estimated to be 0.45. The results for isopropyl nitrite differ in several respects from those for the other two systems. A contribution from a primary process involving an intramolecular rearrangement to nitrosomethane and acetaldehyde cannot be excluded, although an alternative explanation in terms of an excited alkoxy mechanism is suggested.

1. By the reaction of bistrifluoromethylketene with nitrosyl fluoride and with ethyl nitrite the acid fluoride and ethyl ester of 3,3,3-trifluoro-2-nitroso-2-(trifluoromethyl)propionic acid were obtained, and their properties were studied. 2. The reactions of bistrifluoromethylketene with sodium nitrite and with nitrous anhydride, leading to hexafluoroacetone oxime, were investigated.

The reactions of NO(4II) molecules, generated by Hg 6(3P1) photosensitization, with methane, ethane, propane, neopentane, and benzene have been studied at room temperature in a circulatory system. In the case of ethane the following reaction products were identified: N2, N2O, H2O, NO2, CO, CO2, C2H4, acetaldehyde, nitroethane, ethyl nitrite, ethyl nitrate, nitroethylene, nitromethane, methyl nitrite, methyl nitrate, formaldehyde. For hydrocarbon consumption, under comparable conditions, the following quantum yield values were established: [Formula: see text]. The most probable primary process may be represented by the sequence[Formula: see text] [Formula: see text]Alkyl free radicals catalyze the chain disproportionation of nitric oxide at room temperature according to the stoichiometric equation[Formula: see text]A minimal value of 12 was established for the average chain length.

A free radical mechanism is proposed to account for the inhibition of organic decompositions by nitric oxide, based on the assumption that the nitric oxide can both start and stop reaction chains in the substrate. Propylene inhibits organic decompositions and a free radical mechanism appears to account for this effect also. Ethyl nitrite completely inhibits the oxygen promoted chain in acetaldehyde at 300°C but has only a relatively small effect at 500°C.

Die Diazotierung von (Aziridin-1-ylamino)-triphenylphosphoniumbromiden 3 mit Athylnitrit liefert die Azido-brom-Verbindungen 4a – e sowie 6 und 7. p-Allyl-anisol wird als Modell zum Vergleich der Reaktivitaten einer Bromonium-Zwischenstufe C und einer moglichen Azidonium-Zwischenstufe F herangezogen. Wahrend erstere uber ein Anisonium-Ion D durch Bromid- bzw. Azid-Ion zur 1.3-Dibrom-Verbindung 5 bzw. zur 1-Brom-3-azido-Verbindung 8 umgeformt wird, erfolgt bei F keine entsprechende Aryl-Wanderung. Die offnung von B durch das Bromid-Ion last sich mit der meist sterisch kontrollierten Offnung unsymmetrischer Epoxide durch Nucleophile vergleichen. Simulation of Azidonium Ion Intermediates by Reaction of (Aziridin-1-ylamino)-triphenyl-phosphonium Salts with Ethyl Nitrite The diazotization of the (aziridin-1-ylamino)-triphenylphosphonium bromides 3 by means of ethyl nitrite yields the azido-bromo compounds 4a – e, 6 and 7. p-Allylanisole is used for comparison of the reactivities of a bromonium ion intermediate C and a possible azidonium ion intermediate F. C is converted by bromide ion or azide ion via an anisonium ion intermediate D into the 1.3-dibromo compound 5 or the 1-bromo-3-azido compound 8, respectively. There is no analogous aryl migration in the case of intermediate F. The opening of B by the bromide ion can be compared with the sterically controlled opening of unsymmetrical epoxides by nucleophiles.

A method of assay was tried for ethyl nitrite in spirits, based on IR absorbance between 5.5 and 7.0 μ in chloroform solution. Conditions, such as temperature and proportion of alcohol to chloroform in sample, standard, and blank, must be made as closely identical as possible. Experiments indicate that ethyl alcohol, when dissolved in chloroform, shows a prominent peak at 6.17 μ, in the same region as the nitrite group (6.3–6.4 μ). Since the ethyl alcohol in ethyl nitrite spirits has approximately the same infrared absorbance peak as the ethyl nitrite, this procedure does not appear practical.

The infrared spectra of methyl and ethyl nitrite in the gas, in solution and as solids at −180°C have been recorded in the region 4000-220 cm −1 . The Raman spectrum of ethyl nitrite was studied in solution. Both nitrites exist as a mixture of rotational isomers in all the three states of aggregation. Methyl nitrite appears to form a mixed crystal of 1:1 trans—cis ratio after annealing. The isomeric ratio of both nitrites changed with temperature in the gaseous and the liquid states, but no change was observed in solution with solvent polarity. Many of the infrared bands of gaseous methyl nitrite show well resolved contours, supporting the predicted trans geometry for one of the isomers. A vibrational assignment of most of the fundamentals in methyl nitrite is presented and compared with ethyl nitrite and other primary nitrites.

Edible oil deodorizing equipment and processes have been developed as a result of advances in hot-pressing and extraction of oil-bearing materials. Early methods included masking of odors by means of aromatics, washing out of odors and neutralization or destruction of odors by means of various chemical treatments.

Bei der Diazotierung der (Aziridin-1-ylamino)triphenylphosphoniumfluoride 1b, 2b und 3b mit Athylnitrit entstehen nicht analog zu den entsprechenden Bromiden vicinale Fluorazidoverbindungen, sondern die zur Darstellung der Salze eingesetzten Olefine und N2O. Aus den (Aziridin-1-ylamino)triphenylphosphoniumacetaten 1c, 2c und 3c resultieren bei der Diazotierung auserdem die Azidoalkylacetate 7a, 7b, 8 und 10a sowie die Vinylazidoverbindungen 9a, 9b und 10b. Die Reaktion der zu den Aziridinylaminophosphoniumsalzen homologen, aus 1-Amino-3-phenylazetidin und 1-Aminopyrrolidin gewonnenen Phosphoniumbromide 11 und 13 liefert 12 bzw. – uber die Zwischenstufe eines cyclischen Tetramethylenazidoniumions F hinweg – die Azidoverbindung 14. Die Analogize zu den von Olah und Mitarbeitern2) beschriebenen stabilen cyclischen Tetramethylenhaloniumionen einerseits und den instabilen cyclischen Trimethylenhaloniumionen andererseits sind bemerkenswert. – Das aus N-Aminocarbazol hergestellte Phosphoniumbromid 16a liefert unter Diazotierungsbedingungen mit C2H5ONO kein Produkt mit einer Azidofunktion, sondern unter Freisetzung von N2 3-Bromcarbazol (17). Unter vergleichbaren Bedingungen bildet das (Pyrrol-1-ylamino)triphenyl-phosphoniumbromid (15a) zwei symmetrisch substituierte, nicht isolierbare Dibrompyrrole. Simulation of Azidonium Intermediates with the Aid of N-Amino-Heterocycles. The diazotization of the (aziridin-1-ylamino)triphenyl phosphonium fluorides 1b, 2b, and 3b by means of ethyl nitrite does not yield vicinal fluoroazido compounds analogously to the corresponding phosphonium bromides; instead the olefins used for preparation of the phosphonium salts and N2O are formed. Diazotization of the (aziridin-1-ylamino)triphenylphosphonium acetates 1c, 2c, and 3c furnishes the azidoalkyl acetates 7a, 7b, 8, 10a and the vinylazido compounds 9a, 9b, and 10b besides the above olefins and N2O. – The reaction products of the phosphonium bromides 11 and 13 (prepared from 1-amino-3-phenylazetidine and 1-aminopyrrolidine respectively) with ethyl nitrite are 12 and the azido compound 14, formed via a cyclic tetramethylene azidonium ion intermediate F, respectively. The analogies to the stable cyclic tetramethylenehalonium ions on the one hand and to the unstable cyclic trimethylenehalonium ions on the other hand (reported by Olah and co-workers2)) warrant particular attention. – No product with an azido function results on attempted diazotation of the phosphonium bromide 17a with C2H5ONO: 3-bromocarbazole (17) is formed with evolution of N2. Under the same conditions (pyrrol-1-ylamino)triphenylphosphonium bromide 15a affords two symmetrically substituted dibromopyrroles which cannot be isolated.

Methyl nitrate (CH 3 ONO 2 ) is the most explosive of the nitrate esters, and previous studies have been confined mainly to the slow thermal decomposition, and to the vapour phase explosion at low pressures in closed vessels. A stationary decomposition flame has now been maintained and studied spectrographically. A t low pressures the zones of reaction are clearly separated. From the early stages of the flame strong formaldehyde bands are emitted. This decomposition flame has been successfully simulated in artificial mixtures of methyl nitrite with oxygen. The results obtained are in accord with the preliminary fission of the nitrate molecule in the pre-heat zone of the flame: CH 3 ONO 2 →CH 3 O + NO 2 . The combustion flame of m ethyl nitrate with oxygen, nitric oxide and nitrogen dioxide has also been examined at low pressures. At atmospheric pressure, m ethyl nitrite (CH 3 ONO) has been found to support a decomposition flame of very small burning velocity. However, the combustion of m ethyl nitrite with oxygen at atmospheric pressure is an extremely fast and vigorous flame. It has been observed in both pre-mixed and diffusion systems and information about the changes occurring in it have been obtained by absorption and emission spectroscopy. All the experimental results may be interpreted in terms of two general principles: the reluctance of nitric oxide to react except at high temperatures and pressures and the frequent occurrence in flames of extensive pyrolytic reactions before the main reaction zone is reached.

1. 3. 5-Trichlor-2.4.6-tricyan-benzol (2a) reagiert mit den Natriumsalzen von β-Ketoestern unter Austausch von zwei Chloratomen, wobei die Verbindungen 6a–c entstehen. Von diesen ergibt, 6c durch partielle Verseifung und Decarboxylierung 6-Chlor-1.3.5-tricyan-benzoldiessigsaure-(2.4)-diathylester (9), der mit Athylnitrit in Dimethylformamid zum Dioxim 10 reagiert. Aus 10 wird mit Phosphorpentachlorid durch Beckmann-Fragmentierung das Chlorpentacyanbenzol (5) erhalten. Preparation of Chloropentacyanobenzene 1, 3, 5-Trichloro-2,4,6-tricyanobenzene (2a) reacts with the sodium salts of β-ketoesters by exchange of two chlorine atoms to give the compounds 6a–c. Of these 6c, by partial saponification and decarboxylation, yields diethyl 6-chloro-1,3,5-tricyanobenzene-2,4-diacetate (9), which reacts with ethyl nitrite in dimethylformamide to give the dioxime 10. By Beckmann fragmentation of 10 with phosphorus pentachloride chloropentacyanobenzene (5) is obtained.

The combination of ethoxyl radicals with nitric oxide has been studied at low pressures in a flow system at 200°, in comparison with the hydrogen abstraction reaction forming nitroxyl and acetaldehyde. The combination reaction is in the transition zone between second- and third-order at effective total reactor pressures of 0·08–1·6 mm. of diethyl peroxide as third body. The results can be explained on a simple energy-transfer basis. The third-order rate constant is 3 × 1018 mole–2 cm.6 sec.–1, the “half-rate pressure” 0·2 mm., and the lifetime of the energised ethyl nitrite molecule 5 × 10–7 sec. The efficiencies of nitric oxide and neopentane in energy transfer are about 0·05 and 0·6, respectively, relative to diethyl peroxide.

A gas phase isotope exchange reaction has been found to occur between nitric oxide and nitrite esters, RO15NO + 14NO RO14NO + 15NO. The reaction is first order with respect to both nitrite ester and nitric oxide. For the reaction with trifluoroethyl nitrite, the second order rate constant is given by the equation , and for the reaction with ethyl nitrite .

The auto exhaust was irradiated with xenon light or solar light under static conditions, and the concentration changes of hydrocarbons, nitrogen oxides, formaldehyde and irradiation products were analysed. The concentrations of each component were determined by hydrogen flame ionization gas chromatography for hydrocarbons, and colormetry for nitrogen oxides and formaldehyde, and electron capture gas chromatography for irradiation products, respectively. From these experiments, it was noticed that the concentrations of hydrocarbons and nitrogen oxides decreased, whereas that of formaldehyde increased. The irradiation products were also found to be methyl nitrite, ethyl nitrite, methyl nitrate, ethyl nitrate, n-propyl nitrate, isobutyl nitrate, biacetyl and PAN. Therefore these photochemical reactions of auto exhaust were assumed to occur in the atomosphere.

Die Nitrosierung von Methylheterocyclen mit Athylnitrit in Gegenwart von uberschussiger Salzsaure fuhrt zu den Aldoxim-hydrochloriden, die sich mit wasriger Kaliumhydrogencarbonat-Losung in die freien Aldoxime (Tab. 1, S. 44) uberfuhren lassen. Fur den Reaktionsablauf wird die Ausbildung eines quasi-p-chinoiden Zwischenproduktes gefordert. Syntheses in the Heterocyclic Series, XIII1). Nitrosation of Acidic Alkyl Hydrogen in Heterocyclic Compounds On nitrosation with ethyl nitrite in the presence of an excess of hydrogen chloride, methylheterocycles afford hydrochloride salts of the aldoximes which may be liberated by treatment with aqueous potassium hydrogen carbonate. Formation of a quasi-p-quinoid intermediate is thought to be a necessary step in the course of the reaction.

3(5).4-Bis-trimethylsilyl-pyrazol (1) und 4-Trimethylsilyl-pyrazol (2) werden mit Natriumnitrit in Gegenwart von Trifluoressigsaure zu 4-Nitroso-pyrazol (3) nitrosiert. Ebenso bildet sich 3 aus 1 und Athylnitrit/Trifluoressigsaure bzw. Isoamylnitrit//Ameisensaure. Mit Isoamylnitrit allein werden bei hoherer Temperatur 2 zu 3, 1 zu 3(5)-Nitroso-4-trimethylsilyl-pyrazol (5) und 3 sowie 3(5)-Trimethylsilyl-pyrazol (4) zu 3(5)-Nitroso-pyrazol (6) und 3 umgesetzt. Die Nitrosopyrazole 3, 5 und 6 lassen sich leicht zu den entsprechenden Nitroverbindungen oxydieren. — Die saure Hydrolyse von 5 und von 3(5)-Nitro-4-trimethylsilyl-pyrazol (7) fuhrt zu 6 bzw. zu 3(5)-Nitro-pyrazol (8). — Trimethylsilyl-benzol und p-Trimethylsilyl-toluol ergeben mit Alkylnitrit//Trifluoressigsaure Nitrosobenzol bzw. p-Nitrosotoluol. C-Nitrosation via Silyl Derivatives 3(5).4-Bis(trimethylsilyl)pyrazole (1) and 4-(trimethylsilyl)pyrazole (2) are nitrosated with sodium nitrite in the presence of trifluoroacetic acid to form 4-nitrosopyrazole (3). The latter compound is also obtained by treatment of 1 with ethyl nitrite//trifluoroacetic acid or isoamyl nitrite//formic acid. With isoamyl nitrite alone at elevated temperatures 2 gives 3 and 1 gives 3(5)-nitroso-4-(trimethylsilyl)pyrazole (5) and 3. Under the same conditions 3(5)-(trimethylsilyl)pyrazole (4) yields 3(5)-nitrosopyrazole (6) and 3. The nitrosopyrazoles 3, 5 and 6 can be readily oxidized to the corresponding nitro compounds. — Acid hydrolysis of 5 and 3(5)-nitro-4-(trimethylsilyl)pyrazole (7) yields 6 and 3(5)-nitropyrazole (8), respectively. – Trimethylsilylbenzene and p-(trimethylsilyl)toluene react with alkyl nitrite//trifluoroacetic acid to form nitrosobenzene and p-nitrosotoluene, respectively.

A sequence of equations is proposed for the decomposition events of alkyl nitrates, based on the observation that nitrites are produced in substantial amounts. Studies were made of the reactions of ethoxyl radicals (produced by the decomposition of diethyl peroxide at 181 deg C) with ethyl nitrite and NO. The reaction rate between the ethoxyl radicals and NO was much greater than that between the radicals the nitrite.

The peroxyacyl nitrates, a series of eye-irritating plant toxicants, are synthesized by gasphase reactions at low concentrations. They are purified by preparative-scale gas chromatography. The preparation and purification of the first member of the series by photolysis of ethyl nitrite vapor (ca 400 ppm) in oxygen is described in some detail. The entire procedure is designed to minimize factors which might cause decomposition of this extremely unstable product. Pure PAN is stored as a vapor diluted with dry nitrogen at about 100 psig and 40°F. Such mixtures (about 1000 ppm) can be analyzed by infrared spectrophotometry using a 10 cm cell. The product is used in studies of its toxicity toward biological materials, in instrument calibration, and for studies of air pollution chemistry.

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 less than or equal to 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.

While nitrosation of 6-substituted 2, 4-dimethylpyrimidines with ethyl nitrite in liquid ammonia occurred preferentially at the 4-methyl group to give the corresponding pyrimidine-4-aldoximes, the same reaction of 1, 2, 4-trimethyl-6-oxo-1, 6-dihydropyrimidine (IV) afforded 1, 4-dimethyl-6-oxo-1, 6-dihydropyrimidine-2-aldoxime. Acylation of IV with ethyl benzoate and diethyl oxalate under basic conditions also gave α-(1, 4-dimethyl-6-oxo-1, 6-dihydro-2-pyrimidinyl) acetophenone and ethyl 3-(1, 4-dimethyl-6-oxo-1, 6-dihydro-2-pyrimidinyl) pyruvate, respectively.

Benzoylation of 2, 4-dimethyl-(Ia), 2, 4, 6-trimethyl-pyrimidine (Ib), 2, 4-dimethyl-quinazoline (Ic), 2, 4-dimethyl-(Id), 2, 4, 6-trimethyl-pyridine (Ie), and 2, 4-dimethyl-quinoline (If) with ethyl benzoate under basic conditions were performed. In analogy with the nitrosation with ethyl nitrite, methyl groups on the 4-position of IIa-f were preferentially benzoylated to give 4-phenacyl derivatives. Structures of all the products were determined by chemical derivatization.

The microwave spectrum of ethyl nitrite shows the presence of three rotational isomers. Two rotamers correspond to text-decoration:underlinecis, trans[τ1(ON—OC)= 0°, τ2(CC—ON)= 180°] and text-decoration:underlinecis, gauche(τ1= 0°, τ2= 80°) structures. Relative intensities show the text-decoration:underlinecis, gauche to be less stable by 238 ± 50 cm–1. A third rotamer, less stable than the text-decoration:underlinecis, trans by 81 ± 20 cm–1, has been assigned a text-decoration:underlinetrans, gauche structure (τ1= 180°, τ2= 90°). Internal rotation about the C—O bond in the text-decoration:underlinecis isomer has been studied through relative intensities of spectra in excited torsional states. For the text-decoration:underlinetrans isomer, a precise barrier height of 137 ± 7 cm–1 separating the two equivalent gauche forms has been derived from vibration–rotation interactions in the v= 1, C—O torsional state spectra of both text-decoration:underlinetrans, gauche CH3CH2ONO and CD3CD2ONO. Dipole moments for the three rotamers are also reported.

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.

As the starting material for the synthesis of sparteine derivatives, 5-oxosparteine (II) was synthesized. Condensation of Δ5-dehydrosparteine (IX) or Δ1(6)-dehydrosparteinium ion (VIII) and benzaldehyde gave 5-benzylidene-Δ1(6)-dehydrosparteinium ion (X) which was reduced to 5-benzylidenespartein (XI), and its oxidative cleave should have provied II but the objective was not attained. 5-Hydroximinosparteinium ion was obtained by the condensation of IX and nitrosyl chloride or VIII and ethyl nitrite, this sparteinium ion was reduced to 5-hydroximinosparteine (XIII), and its treatment with pyruvic acid gave the objective II. II has the same configuration as that of sparteine.

n/a

IT was reported by Simpson1 that 2,4-dinitrophenol, at a concentration of 1 mM, strongly inhibits nitrite oxidation by Nitrobacter, although compounds such as ethyl nitrite and nitromethane appeared to have no inhibitory action. Other workers2 have, however, failed to obtain any inhibition with 2,4-dinitrophenol. We have therefore re-investigated the effect of this compound on nitrite oxidation.

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.

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.

The microwave spectrum of ethyl nitrite shows the presence of three rotational isomers. Two rotamers correspond to text-decoration:underlinecis, trans[τ1(ON—OC)= 0°, τ2(CC—ON)= 180°] and text-decoration:underlinecis, gauche(τ1= 0°, τ2= 80°) structures. Relative intensities show the text-decoration:underlinecis, gauche to be less stable by 238 ± 50 cm–1. A third rotamer, less stable than the text-decoration:underlinecis, trans by 81 ± 20 cm–1, has been assigned a text-decoration:underlinetrans, gauche structure (τ1= 180°, τ2= 90°). Internal rotation about the C—O bond in the text-decoration:underlinecis isomer has been studied through relative intensities of spectra in excited torsional states. For the text-decoration:underlinetrans isomer, a precise barrier height of 137 ± 7 cm–1 separating the two equivalent gauche forms has been derived from vibration–rotation interactions in the v= 1, C—O torsional state spectra of both text-decoration:underlinetrans, gauche CH3CH2ONO and CD3CD2ONO. Dipole moments for the three rotamers are also reported.

The reactions of oxygen atoms with methyl nitrite and with ethyl nitrite have been studied in a discharge flow system between 300 and 410 K. Initial attack is by abstraction of a hydrogen atom, for which the rate expressions are 1.4 × 1010 exp(–21.8 ± 2 kJ mol–1/RT) and 2.6 × 1010 exp(–20.3 ± 2 kJ mol–1/RT) dm3 mol–1 s–1. The activation energy for hydrogen abstraction is not reduced by the fact that the initially formed radical can rupture exothermically to yield an aldehyde and nitric oxide.

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.

THE value of gas chromatography as a technique for the analysis of the minute quantities of products formed during the kinetic studies of gas reactions is well illustrated by recent work on the gas-phase reaction between ethyl nitrite and nitrogen dioxide. Studies of the behaviour of ethyl nitrite, ethyl nitrate and water on a partition column of kieselguhr wetted with di-butyl-phthalate and eluted with nitrogen revealed that a complete separation of a mixture of the esters and water can be achieved. Using gas chromatography, it has thus been possible to identify three major components, namely, ethyl nitrite, ethyl nitrate, and water, in the residue from the reaction between ethyl nitrite and nitrogen dioxide at about 190° C. Few other micro-analytical techniques would have enabled this to be done so simply or so quickly.