Nitric-Sulphuric Acid

High silicon iron offers excellent resistance to attack by all concentrations of nitric-sulphuric acid mixtures. The mixed acid corrodes the iron at rates never greater and often lower than the individual acids of comparable concentration. 

In a quite analogous way ethylene reacts with nitric-sulphuric acid, nitroethyl nitrate (p. 164) being produced. How are alkyl sulphonic... 

The action of concentrated sulphuric acid and the formation of mixed sulphuric-nitric esters, as well as the action of nitric add and mixtures of nitric—sulphuric acid and water and of hydrochloric acid have been discussed above. Concentrated hydriodic acid of 1.5 density decomposes nitroglycerine to glycerol and nitric oxides. 

Naoum [4] nitrated 1,3-butylene glycol and obtained a yield of 93.7%, i.e. from 100 parts of butylene glycol, 187.5 parts of dinitrate were obtained. (See also Mati-gnon et al. [36], Aubry [37]). Aubertein [42], however, pointed out the difficulty of nitrating 1,3-butylene glycol with nitric-sulphuric acid mixtures. 

On a small scale methyl nitrate can be obtained by carefully distilling a mixture of methyl alcohol with nitric add containing urea nitrate [18] or with nitric-sulphuric acid mixture at 40 or 18°C [19]. 

Another major manufacturer was the Eastern Dynamite Corporation, at Wilmington, Delaware, which developed the patents of Holmes [26]. The starch was nitrated by means of mixed nitric-sulphuric acid and then stabilized by prolonged boiling with water in the presence of calcium carbonate, for 75-100 hr. In later patents the addition of ammonium salts to the water was recommended. 

Oxidation of the dihydropyridine derivative is most conveniently carried out with an aqueous nitric-sulphuric acid mixture. Removal of the ethoxycarbonyl groups may be achieved by a stepwise hydrolysis and decarboxylation sequence, but the one-step reaction described in Expt 8.29 using soda-lime is convenient. 

Some colour tests for pesticides are described under Colour Tests, including Nitric-Sulphuric Acid (p. 143) for dicophane. Phosphorus Test (p. 144) for organophosphorus compounds. Sodium Didiionite (p. 144) for diquat and paraquat, and Sulphiuic Acid-Fuming Sulphuric Acid (p. 146) for dielihin, alihin, and endrin. 

Colour Tests. Nitric-Sulphuric Acid—pink Sulphuric Acid-Fuming Sulphuric Acid—red (slow). 

Colour Tests. Liebermann s Test—brown Nitric-Sulphuric Acid—red - orange - green. 

Giles, Hanson and Ismail [19 found that in mononitration of toluene with a standard nitration mixture of nitric-sulphuric acid and water, the organic phase contained nitric and nitrous acids, but did not include sulphuric acid and water. The authors also studied the role of agitation. Their conclusion was simitar to that reported previously [2) that mass transfer between the phases plays an important role, and a fast reaction takes place in a zone in the aqueous phase adjacent to the interface. It is important to know the diffusivity of the aromatic substrate in the aqueous phase which depends on the design of the nitra-tor. The paper by Strachan [20j also points out the importance of mass transfer in agreement with a previously described statement (Vol. 1, p. 49). 

As pointed out in Vol. I. p. 146 nitrate ester of -niiroeihanol can be formed by passing ethylene into a nitric-sulphuric acid mixture, and a side reaction is the formation of ethylene glycol dinitratc. However in most experiments nitro-niiraie ester is the minor product of the reaction. The reactions of aikencs with N2O4 were described in the excellent review paper by Shechtcr [50]. The classic work of N. Levy. Scaife et al. (Vol. 1. pp. 594-5) [51 53] should be mentioned... 

Butanotriol is nitrated to trinitrate with a nitric -sulphuric acid mixture. The nitrated product shows good stability. Il is less volatile than nitroglycerine and according to. Meyer is in use for tropic-proof double base powder. 

Nitration with nitric acid-sulphuric acid. The addition of a small proportion of sulphuric acid to nitric acid prevents dissolving PVA in nitric acid. A suspension of PVA in nitric/sulphuric acid mixture is formed. Tlic yield of PVN is best when the concentration of 112804 in the mixed acid is 10-30% (Fig. 64). In such a mixed acid the solubility of PV.N is negligible and the only substances dissolved in the acid are some degradation viscous products in quantity of 2-3%. They can be precipitated with water. 

Fieser and Campbell [71] nitrated dehydroabietic acid with nitric-sulphuric acid mixtures and obtained a product Ci9H25(N02)2C00H, decomposition 178-185 C, identical with this described by Johansson. This was 6,8-dinitro-dehydroabietic acid. It seems to be identical with one of the non-identihed products with three ( ) NO2 groups of Dubourg [69]. 

In a nitric-sulphuric acid mixture at 0 °C, the diethoxyphosphinylamino group in dialkyl A -phenylphosphoramidates is mostly meta directing, although with substantial para directing ability, whereas the dimethoxyphosphinothioyl group is almost completely para directing. ... 

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