Nitrogen trichloride sources

The reactions of endothermic compounds with atoms are useful sources of energy rich species and free radicals. Ozone and chlorine dioxide are the compounds which have been most fully studied, but atom reactions with the difficult compounds nitrogen trichloride and the azides of chlorine and bromine are also interesting. The reactions of H( S), 0( P), N( S), F, Cl, Br and IfPs/a) have all received study by the discharge-flow method, and these cases are chosen to exemplify the features of this class of reactions. 

The next two sections discuss protection against process hazards that are peculiar to chlorine processing. Section 9.1.10 covers emergency pressure relief both before and after the compressors. An important part of the discussion covers the design and operation of vent scrubbers to prevent the release of chlorine to the environment. Section 9.1.11 is dedicated to the explosion hazards presented by hydrogen and nitrogen trichloride. The sources of NCI3 are discussed, as well as its fate in the process. This includes the mechanisms of accumulation and safe decomposition. 

Standard commercial grades of acid usually are suitable. Byproduct acid is widely available commercially, and it is important for the user to know his ultimate source and to adopt the proper quality assurance program. Troublesome impurities may include heavy organics, which can form chlorine compounds that remain with the product, and nitrogen compounds, which can form nitrogen trichloride (Section 9.1.11.2A). 

When large amounts of chlorine gas are required or when the chlorination process needs pressurized gas, liquid chlorine must be vaporized and superheated to avoid liquefaction [243], [244]. It is advisable to operate the vaporizer at a sufficiently high temperature to accelerate the decomposition of nitrogen trichloride. As a source of heat, steam with a maximum allowed temperature of 120 C is used when the vaporizing system is constructed of mild steel. Water above 60 C is also suitable, as shown in Figure 84. Direct electrical heating is not appropriate because there is always a risk of overheating the steel. 

Pamphlet 9 of the Chlorine Institute gives very useful recommendations for application of chlorine vaporizers including some references such as autoignition (rapid corrosion of steel at high temperatures when chlorine encounters a hydrocarbon at the steel surface). Consult the information source about possible difficulties due to concentration of nitrogen trichloride over a long period of time. 

Nucleophilic attack at nitrogen is rare in these systems. However, the inorganic trithiazyl trichloride (87) acts as an apparent source of electrophilic nitrogen on reaction with certain organic substrates. Reaction with electron-rich alkenes such as stilbene gives 3,4-diphenyl-1,2,5-thiadiazole (77JCS(Pl)916>. 

Croft explains the results in terms of the acceptor property of the boron atoms. They tend to take an electron pair from a donor molecule to form sp bonds. This is why only halides in lower oxidation states react with boron nitride (e.g., CuCl and SbCls but not Cuds or SbCls) This is different from the case of graphite in which the carbon planes are a source of electrons. The intercalation of aluminum and ferric chlorides is attributed by Croft to bonding by the electron pairs of the nitrogen atoms of boron nitride. It is surprising, however, that boron trifluoride and trichloride, which are particularly good electron acceptors, appear unable to become intercalated. 

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