Nitrosyl chloride, decomposition

By following the pressure change, Ashmore and Spencer studied both the decomposition of nitrosyl chloride at 523 and 573°K and the combination of nitric oxide and chlorine at temperatures from 430 to 573°K. In the case of nitrosyl chloride decomposition, the initial rate law can be written as... 

The nitrites aie most conveniently prepared from the corresponding alcohols by treatment with nitrosyl chloride in pyridine. The crude nitrites can be precipitated by addition of water and recrystallized from appropriate solvents. However nitrites prepared from carbinols in which the adjacent carbon is substituted by halogen, free or esterified hydroxyl or a carbonyl function are very readily hydrolyzed and must be recrystallized with great care. In general the photolysis gives higher yields if purified and dried nitrites are used which do not contain acids or pyridine, although occasionally the addition of small amounts of pyridine is recommended in order to prevent hydrolysis of the nitrite. Traces of acids do in fact catalyze the thermal decomposition of secondary nitrites to equimolar amounts of alcohol and ketone. ... 

Decomposition Toxic gases and vapors (such as oxides of nitrogen, phosgene, nitrosyl chloride, chlorine, and carbon monoxide) may be released when chloropicrin decomposes. 

A novel, mild system for the direct nitration of calixarenes has been developed using potassium nitrate and aluminum chloride at low temperature. The side products of decomposition formed under conventional conditions are not observed in this system, and the p-nitro-calixarenes are isolated in 75-89% yields.17 Such Friedel-Crafts-type nitration using nitryl chloride and aluminum chloride affords a convenient system for aromatic nitration.18 Nitryl chloride was previously prepared either by the oxidation of nitrosyl chloride or by the reaction of chlorosulfonic acid with nitric acid. However, these procedures are inconvenient and dangerous. Recently, a mixture of sodium nitrate and trimethysilyl chloride (TMSC1) has been developed as a convenient method for the in situ generation of nitryl chloride (Eq. 2.6). 

In cold carbon tetrachloride, a number of ketimines have been nitrosated with nitrosyl chloride. The A-nitrosoketimines exhibit varying degrees of stability. This stability is enhanced in the case of A-nitrosobenzophenonimines by electron-withdrawing substituents on the benzene ring and by the presence of bulky substituents on the ketimine carbon atom. Unhindered A-nitrosoketimines may decompose at room temperature or even below. This observation is considered to be consistent with a low activation energy for the decomposition and a substantial contribution of the 1,4-dipolar structure (III), in Eq. (16), to the ground state. Structures III, IV, and V represent possible resonance structures of the A-nitrosoketimines [64a]. 

Part of the nitroglycerine dissolved in this mixture of acids undergoes hydrolysis. Concentrated hydrochloric acid does not dissolve nitroglycerine. On heating, a gradual decomposition occurs accompanied by a dark yellow colour due to hydrolysis and the production of nitrosyl chloride. 

The work by Ashmore and co-workers on the nitric oxide-chlorine system has already been mentioned in the context of reactions of nitric oxide with molecular halogens. It was first suggested in 1953 by Ashmore and Chanmugam10 that the second-order molecular mechanism for the thermal decomposition of nitrosyl chloride might be accompanied by a radical mechanism at higher temperatures, which they envisioned as... 

The picture is somewhat further complicated by more recent shock-tube results, obtained by Deklau and Palmer,115 on the decomposition of nitrosyl chloride over the temperature range 880-1350°K. Deklau and Palmer made the untenable assumption that in the presence of C1NO and argon, the rate law could be written as... 

Instead of diazotation of >-aminostyrene units, the nitrosation of their acetamino derivatives with nitrosyl chloride has been described by Hahn (94), as well as the synthesis of diazoamino compounds. On decomposition these groups furnish active sites for monomer growth, e. g. acrylonitrile. s... 

Other processes for making chlorine include sodium manufacture, caustic potash manufacture, hydrogen chloride decomposition, the nitro-syl chloride (NOC1) process, and a process where salt is treated with nitric acid to form sodium nitrate and chlorine with nitrosyl chloride (containing 4 to 10% nitrogen tetroxide) as a by-product. The nitrosyl chloride vapor is placed in contact with oxygen to produce nitrogen tetroxide and chlorine ... 

Ashmore, P. G., and J. Chanmugam Reactions in the system hydrogen, chlorine, nitric oxide, and nitrosyl chloride. Part 2. — The thermal decomposition of nitrosyl chloride. Trans. Faraday Soc. 49, 265 (1953). 

With the intention of extending the nitrogen chain of tetrazene, tet-razenides 62 and 64 were allowed to react with nitrogen halides as well as their derivatives. The desired objective could not be reached in any case because of decomposition of the expected compounds. Thus, reactions of 62 with nitrosyl chloride (NOX X = Cl) and 64 with isoamyl nitrite (NOX X = 0(/-CsHn)] at low temperature in ether occur according to Eqs. (95) and (96) via 73 and 74 (45), respectively, whereas reactions of 62 with phenyldiazonium chloride (PhN=N Cl ) or tosyl azide (TsN, Ts = P-T0ISO2) at — 78°C develop according to Eqs. (97) and (98), probably via 75 and 76, respectively. 

DOT CLASSIFICATION 8 Label Corrosive SAFETY PROFILE A corrosive irritant to the eyes, skin, and mucous membranes. When heated to decomposition it emits ver toxic HCl, HNO3, CT, and NOx. See also HYDROCHLORIC ACID, NITRIC ACID, and NITROSYL CHLORIDE. 

The gas-phase reaction of nitric oxide with chlorine has received a great deal of attention. Very often it has been studied concurrently with its reverse, the decomposition of nitrosyl chloride, viz. 

Storage of nitrosyl fluoride in the glass reaction vessel containing KF is possible for a few days however, the use of an inert-metal vessel containing anhydrous KF is preferred for an extended period of time. Nitrosyl chloride is stable at room temperatxure but will always contain a small amount of NO and CU because of its reversible decomposition of 0.5%. The reversible decomposition of nitrosyl bromide is appreciable enough at room temperature (7 %) to require storage at a lower temperature, or the gas can be prepared immediately prior to use. ... 

Cyclopropanoxyl radicals were generated by thermal and photochemical decomposition of cyclopropyl nitrites.The nitrites were prepared from cyclopropanols and nitrosyl chloride in pyridine, and they decomposed at low temperatures often below room temperature. A mixture of -bromo and jS-nitroso ketones was formed from the photolysis of pentamethylcyclo-propyl nitrite (19) in bromotrichloromethane. " ... 

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