Nitration, in acetic acid

D) No general reaction can be cited for the preparation of crystalline derivatives of Class (iii). Triphenylamine, when nitrated in acetic acid with fuming nitric acid, gives tri-/>-nitrophenylamine, m.p. 280°. The presence of substituents in the phenyl groups may however complicate or invalidate nitration. 

Nitration in acetic acid, in sulpholan and in carbon tetrachloride showed kinetic phenomena similar to those shown in nitromethane this is significant for it denies nitromethane a chemical involvement in the slow step. (Originally the rate of isomerization of nitromethane to its aci-form was believed to be a factor in the reaction. )... 

The anticatalytic effect of nitrous acid in nitration The effect of nitrous acid was first observed for zeroth-order nitrations in nitromethane ( 3.2). The effect was a true negative catalysis the kinetic order was not affected, and nitrous acid was neither consumed nor produced by the nitration. The same was true for nitration in acetic acid. In the zeroth-order nitrations the rate depended on the reciprocal of the square root of the concentration of nitrous acid =... 

First-order nitrations. The kinetics of nitrations in solutions of acetyl nitrate in acetic anhydride were first investigated by Wibaut. He obtained evidence for a second-order rate law, but this was subsequently disproved. A more detailed study was made using benzene, toluene, chloro- and bromo-benzene. The rate of nitration of benzene was found to be of the first order in the concentration of aromatic and third order in the concentration of acetyl nitrate the latter conclusion disagrees with later work (see below). Nitration in solutions containing similar concentrations of acetyl nitrate in acetic acid was too slow to measure, but was accelerated slightly by the addition of more acetic anhydride. Similar solutions in carbon tetrachloride nitrated benzene too quickly, and the concentration of acetyl nitrate had to be reduced from 0-7 to o-i mol 1 to permit the observation of a rate similar to that which the more concentrated solution yields in acetic anhydride. 

Acid—Base Chemistry. Acetic acid dissociates in water, pK = 4.76 at 25°C. It is a mild acid which can be used for analysis of bases too weak to detect in water (26). It readily neutralizes the ordinary hydroxides of the alkaU metals and the alkaline earths to form the corresponding acetates. When the cmde material pyroligneous acid is neutralized with limestone or magnesia the commercial acetate of lime or acetate of magnesia is obtained (7). Acetic acid accepts protons only from the strongest acids such as nitric acid and sulfuric acid. Other acids exhibit very powerful, superacid properties in acetic acid solutions and are thus useful catalysts for esterifications of olefins and alcohols (27). Nitrations conducted in acetic acid solvent are effected because of the formation of the nitronium ion, NO Hexamethylenetetramine [100-97-0] may be nitrated in acetic acid solvent to yield the explosive cycl o trim ethyl en etrin itram in e [121 -82-4] also known as cyclonit or RDX. 

To prepare fervenulin 4-oxides 12 or toxoflavine 4-oxides 146, it is convenient to use the reaction of l,3-dimethyl-2,4-dioxopyrimidin-6-yl hydrazone 147 or N-(3-methyl-2,4-dioxopyiimidin-6-yl) iV-methylhydrazone 148 with potassium nitrate in acetic acid [75CPB1885,76CPB338,76JCS(CC)658,82JHC1309,93CPB362]. Diethyl azodicarboxylate can be used instead of potassium nitrate [76JCS(P1 )713]. 

Anilinofervenulin 4-oxides 151 were synthesized by the reaction of 6-hydra-zino-l,3-dimethyluracil with triethyl orthoformate, followed by the treatment of the hydrazide 152 with aniline and further cylization of 153 in the presence of potassium nitrate in acetic acid (82JHC1309). 

Silver Pentaglyceryl Trinitramine). CH3.C(CH2NAgN02)3l mw 572.81, N 14.68%. OB to C02 -23.74%, sol in aq ammonia. Prepn from pentaglyceryl trinitrourethane in ammoni-acal soln upon addition of Ag nitrate in acetic acid. The Ag salt detonates when heated Refs 1) Beil — not found 2) Blomquist, OSRD 4134(1944)... 

Bachmann A process for making the explosive RDX. Hexamethylene tetramine is nitrated in acetic acid solution, using a mixture of ammonium nitrate and acetic anhydride. Invented by W. E. Bachmann at the University of Michigan during World War II. See also KA, Woolwich. 

Nitration of 1-hydroxyquinolizinium nitrate affords only a 31% yield of the betaine nitrated at the 2-position (64JCS3030). With quinolizin-4-one (14), which may be regarded as the betaine of 4-hydroxyquinolizinium ion, nitration in acetic acid at room temperature gives a 43% yield of 1,3-dinitroquinolizone. Only by use of cupric nitrate in acetic anhydride is there some mononitration (a mixture of 1- and 3-isomers), but here again the major product is the dinitro compound (64T1051). 

The foregoing dinitro-compound is nitrated in acetic acid solution with nitric acid of density 1 4 at the ordinary temperature. It forms opaque prisms, melting indefinitely at 220° to 223° C., sparingly soluble in alcohol, easily soluble in benzene or acetic acid. With sodium hydroxide its suspension in alcohol gives the pure blue colour of the sodium salt. Thb same result is obtained by treating a nitric-acetic acid solution of the dinitro-compound with sodium nitrite. 

The oxidation reaction of alkylaromatic compounds with cerium-ammonium nitrate in acetic acid medium is crucial for understanding the problem (Baciocchi, Rob, Man-dolini 1980) ... 

The nitration in acetic acid of mesitylene, p-xylene, ethylbenzene and toluene ([aromatic] > 4 x io-2 mol l-1) was zeroth-order in the concentration of the aromatic compound.9 Values of the zeroth-order rate constants at 20 °C were 4 25 x io-6 mol l-1 s 1 ([HNOs] = 5 0 mol l-1) and 6 o x io-5 mol l-1 s 1 ([HN03] = 7 0 mol l-1). The nitration of benzene could be brought under the control of a zeroth-order rate... 

The electrophilic substitution reactions of 1,3-dimethylpyrrolo[3,2-coupling yield 7-substituted products. However, nitration in acetic acid gives primarily attack at position 6. In some reactions 6,7-disubstitution is observed [95CHE(30)1077]. 

Another anomalous orientation is observed in the nitration of 2-methylindole in sulfuric acid, which affords the 5-nitro derivative almost exclusively.257, 258 However, nitration in acetic acid yields the expected 3-nitro isomer. It has been shown258 that whereas nitration in acetic acid involves free indole, nitration in sulfuric acid proceeds through the protonated form (31). 

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