Nitrosyl chloride sulphuric acid

Nitrosylsulphuric acid, and nitrosyl chloride formed as a result of chloride in the water, can cause corrosion in sulphuric acid and lead-chamber plants. Alloying is not generally beneficial in this instance and some elements (such as copper) can increase the corrosion rate. 

Preparation of Nitrosyl Chloride by Reacting Nitrosyl-Sulphuric Acid with Sodium Chloride. Assemble an apparatus as shown in Fig. 89. Fill the system with dry nitrogen. Introduce into a flask... 

Formation.—When sulphur dioxide is passed into ice-cold fuming nitric acid, crystals of nitrosulphonic. acid separate.1 The acid is also obtained when sulphuric acid is treated with excess of nitrogen peroxide.2 It is also formed by the interaction of sulphur dioxide and nitrogen peroxide both in the absence or presence of water,8 and by the addition in equimolecular proportion of liquid nitrogen tetroxide to chloro-sulphonic acid in the absence of moisture.4 Sulphuric acid acts on either nitrous anhydride or nitrosyl chloride with formation of nitrosulphonic acid, according to the equations ... 

It may also be obtained by the action of nitrosyl chloride on sulphuric anhydride. It is a -white, leafy, crystalline mass, somewhat resembling stearic acid in appearance. It is decomposed by moist air with formation of sulphuric, hydrochloric and nitric acids.1... 

The alkenes are distinguished from the alkanes by their solubility in concentrated sulphuric acid and their characteristic reactions with dilute potassium permanganate solution and with bromine. Characterisation may be based upon the determination of their physical and/or spectral properties. Characterisation by way of solid adducts with nitrosyl chloride has been quite widely used in the terpene field the preparation of adducts with 2,4-dinitrobenzenesulphenyl chloride is described below (see also Section 8.1.1, p. 1128). 

Tropolone can be converted into its S nitroso derivative in good yield using barium nitrite and sulphuric acid [245], nitrous acid or sodium nitrite in acetic acid [300,301], or nitrosyl chloride in acetic anhydride [301]. 5-Substituted tropolones usually resist nitrosation. 

Some organic compounds form coloured products if they are oxidized by nitrate ions in acid solution. Examples are brucine (Jenkins and Medsker, 1964), diphenylbenzidine Atkins, 1954), reduced strychnidine Dal Pont, 1962), diphenylamine Isaeva, 1958) and resorcinol Costa, 1951). However, no reliable trouble-free method has been developed based on this technique. Another spectrophotometric method based on the formation of nitrosyl chloride in seawater containing 50 % concentrated sulphuric acid has been developed by Armstrong (1963), but this method cannot be recommended because of the difficulties connected with handling concentrated sulphuric acid solutions at sea, and because it is relatively insensitive. 

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