P nitration

To elevate p-selectivity in nitration of toluene is another important task. Commercial production of p-nitrotoluene up to now leads with twofold amount to the unwanted o-isomer. This stems from the statistical percentage of o m p nitration (63 3 34). Delaude et al. (1993) enumerate such a relative distribution of the unpaired electron densities in the toluene cation-radical—ipso 1/3, ortho 1/12, meta 1/12, and para 1/3. As seen, the para position is the one favored for nitration by the attack of NO (or NO2 ) radical. A procednre was described (Delande et al. 1993) that used montmorillonite clay supported copper (cupric) nitrate (claycop) in the presence of acetic anhydride (to remove excess humidity) and with carbon tetrachloride as a medinm, at room temperature. Nitrotoluene was isolated almost quantitatively with 23 1 76 ratio of ortho/meta/para mononitrotoluene. 

Caps are loaded with one or more of the o- or p-nitrated quinone diazides of polymeric phenols or their metallic salts. These compds are used either as a top chge over a base chge such as Tetryl, TNT or PETN, or in admixt with the usual compn components) 72)J.E.Burns,USP... 

Figure 11.6 Results from seasonal in situ bioassays in the southwest basin of Pamlico Sound. Bars are means of 5 replicates and error bars are on standard deviation.The top panel shows the response of primary productivity of the natural phytoplankton community to the addition of nitrate (+N, 20 pM-N), phosphate (+P, 5 pM-P), nitrate and phosphate (+NP), and the un-amended control.The bottom panel shows the response of chlorophyll a to the same treatments. Relative to controls, strong N limitation was observed in Pamlico Sound despite high load of N to the upstream Neuse River Estuary.

Lima ES, Bonim MG, Augusto O, Barbeiro HV, Souza HP, Abdalla DS. P. Nitrated lipids decompose to nitric oxide and lipid radicals and cause vasorelaxation. Free Rad. Biol. Med. 2005 39 532-539. 

The nitration of toluene may be catalysed by lead(iv), with high selectivity for p-nitration, probably as a result of ligand exchange of acetate with nitrate, giving a species that collapses under the acidic conditions to generate the electrophilic nitronium ion as shown in Scheme 22.14. It is of interest, though, that this catalytic behaviour is not seen with higher all lbenzenes. ... 

The azo-compounds are usually very stable, and can be directly chlorinated, nitrated and sulphonated. On vigorous reduction the molecule splits at the azo group to give two molecules of primary amines, e.g. bcnzene-azophenol gives PhNH2 and p-HOC H NHa. 

QHsNjO, OCCH CH.ONO ),. Formed by the nitration of diethyleneglycol. Viscous, colourless, odourless liquid m.p. — ll-5" C. Used to replace nitroglycerin as a propellant. 

CH3CH(0H)C(0)0Et. A colourless liquid with a pleasant odour, b.p. 154 C. Manufactured by distilling a mixture of ( )-lactic acid, ethanol and benzene in the presence of a little sulphuric or benzenesulphonic acid. It is a solvent for cellulose nitrate and acetate and also for various resins. Used as a lacquer solvent. 

Glycerol ct-dichlorohydrin, sym-dichloroiso-propyl alcohol, 1,3-dichloro-2-hydroxypropane, CH2CI-CHOH-CH2C1. Colourless liquid with an ethereal odour b.p. 174-175" C. Prepared by passing dry HCl into glycerin containing 2% elhanoic acid at 100-1 lO C. Converted to x-epichlorohydrin by K.OH, Used as a solvent for cellulose nitrate and resins. 

C5H10O2, CHjCOOPr. Colourless liquid with a fragrant odour b.p. 88 C. Manufactured by leading propene into hot ethanoic acid containing sulphuric acid, or by heating isopropyl alcohol with ethanoic and sulphuric acids. Used as a solvent for cellulose nitrate and various gums. 

Prepared by heating p-nitrochlorobenzene with concentrated aqueous ammonia in an autoclave at 170°C. It is also prepared by alkaline hydrolysis of p-nitroacetanilide or by nitrating and hydrolysing benzylideneaniline. 

A mixture of the two mononitro-chlorobenzenes is prepared by nitration of chlorobenzene. Further nitration of the mixture or of either of the mononitro-compounds gives 2,4-dinitrochlorobenzene, m.p. 5 C, b.p. 315"C. 

Bright yellow needles m.p. 45 C, b.p. 2 4°C. Prepared together with 4-nitrophenol by careful nitration of phenol. Sodium sulphide reduces it to 2-aminophenol which is used in dyestuffs and photographic processes. 

Further nitration of the 2- and 4- isomers yields 2,4-dinitrotoluene, yellow crystals, m.p. 71 "C. This material is reduced to 2,4-di-aminotoluene and treated with phosgene to give 2,4-diisocyanatotoluene, a precursor of polyurethanes. 

Me2C = CHCOCH= CMca- Yellow liquid having a camphor-like odour m.p. 28 C, b.p. 198-5°C. It is formed when propanone is saturated with HCl and allowed to stand. Resembles camphor in many of its properties and is a solvent for cellulose nitrate. Used to prepare diisobutyl ketone (reduction). 

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