Methyl nitrite, atmosphere

In addition to the Hquid-phase -butyl nitrite (BN) process, UBE Industries has estabHshed an industrial gas-phase process using methyl nitrite (50—52). The oudine of the process is described in Eigure 4 (52). This gas-phase process is operated under lower reaction pressure (at atmospheric pressure up to 490 kPa = 71 psi) and is more economical than the Hquid-phase process because of the foUowing reasons owing to the low pressure operation, the consumption of electricity is largely reduced (—60%) dimethyl oxalate (DMO) formation and the methyl nitrite (MN) regeneration reaction are mn... 

Methyl nitrite burns vigorously with oxygen at atmospheric pressure giving a very fast flame. It will also support a very feeble, slow self-decomposition flame [122—124]. The latter is orange-red and the burning velocity [125], relative to the unburnt gas at 18 °C, is about 3.5 cm.sec , while the global activation energy [126] is 37.5 kcal.mole . The final products of the flame are represented by the stoichiometric equation... 

Taylor W. D., T. D. Allston, M. J. Moscato, G. B. Fazekas, R. Kozlowski and G. A. Takacs Atmospheric photodissociation lifetimes for nitromethane, methyl nitrite and methyl nitrate, Int. J. Chem. Kinet. 12... 

Alkyl halides (RX X = Cl, I) are an important source of halogens in the atmosphere. The major tropospheric sinks of these compounds are photolysis (RBr, RI) and reaction with OH radicals. In the case of alkyl iodides (RI) relative kinetic studies of their OH reactions in photoreactors are complicated by fast reactions with the 0( P) atoms generated by the photochemical OH radical sources. Figure 1 below shows a In-ln plot of the kinetic data from an experiment performed in a large photoreactor to determine the OH rate coefficient for the reaction OH + CH3CH2CH2I relative to OH + ethene using the photolysis of methyl nitrite (CH3ONO) as the OH radical source. A recent example of the implementation of the relative kinetic technique for the determination of OH radical rate coefficients in a photoreactor can be found in Olariu et al. (2000). 

Methyl nitrite is the first member of this class of organic compounds, and photolysis is its only important atmospheric loss process... 

According to a, pj, and <5 values from experiments, the calculated mass burning rates of methyl nitrite, diethyleneglycol dinitrate, and nitroglycerine in one standard atmosphere press are 0.25, 0.26, and 0.25 g/cm s, separately. It is concluded that the right side of Eq. 2.19 is approximated as a constant. If the pressure is 1 atm, it is 0.25 g/cm s. When the burning rate is over 0.25 g/cm s, detonation of liquid explosives is possible. 

VIII-I-2.3. Summary of the Atmospheric Fate of Methyl Nitrite... 

The atmospheric lifetime of methyl nitrite with respect to reaction with OH radicals is estimated to be around 1 month. Methyl nitrite is dissociated quite rapidly by solar radiation, as it absorbs strongly in the actinic region the lifetime for photodissociation with an overhead Sun is about 8 1 min. (see table IX-M-1). Because of this rapid photolysis, other reactions such as with OH radicals are considered to be of minor importance as loss processes for this species from the atmosphere. 

In an apparatus suitably protected against atmospheric moisture and fitted with a gas-inlet tube, mechanical stirrer, and an efficient reflux condenser, to a solution of 45 gm (0.45 mole) of ethyl isopropyl ketone and 5 gm of freshly distilled acetyl chloride is added, through the gas-inlet tube, 18 gm (0.24 mole) of ethyl nitrite at 45°-55°C over a 2 hr period. The reaction mixture is stored overnight in a refrigerator, whereupon 15.2 gm (48.7% based on ethyl nitrite used) of 2-methyl-2-nitroso-3-pentanone dimer (bimolecular ethyl a-nitroso-isopropyl ketone) deposits. The product is isolated by filtration, m.p. 122°-123°C. 

To a solution of 4-hydroxy-2-nitroacetanilide (594 mg, 3.03 mmol) in anhydrous MeOH (5 mL) was added boron trifluoride dimethanol complex (0.98 mL, 9.08 mmol). The solution was stirred for 5 h under reflux and subsequently cooled to -15 °C. After addition of t-butyl nitrite (0.36 mL, 3.03 mmol), the solution was stirred for 20 min while raising the temperature to 0 °C. To the reaction mixture was added methyl acrylate (0.41 mL, 4.54 mmol) and Pd(OAc)2 (34 mg, 5 mol%). The solution was stirred overnight at ambient temperature. After addition of activated charcoal (85 mg) the reaction mixture was stirred under Hz-atmosphere (1 bar) for 24 h. The reaction was quenched with 1 M HCl-solution (20 mL) and extracted with MTBE (60 mL). The combined organic layers were dried with MgS04, filtered, and concentrated under reduced pressure. The residue was purified by column chromatography (Si02, MTBE) to afford 7-hydroxy-3,4-dihydroquinolin-2(l//)-one (425 mg, 86%) as a colorless solid mp 233 °C. ... 

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