Dichlorobenzene nitration

The electrophilic aromatic substitution of aryl halides takes place less readily than with benzene (electron-withdrawing effect), but occurs at the ortho and para positions (the lone pairs on the halogen assist in delocalizing the positive charge in the intermediate). Further chlorination of chlorobenzene, in the presence of aluminium or iron trichlorides, gives 1,4-dichlorobenzene and some 1,2-dichlorobenzene. Nitration normally occurs to give the 2- and 4-nitro- and 2,4-dinitrochlorobenzenes (Scheme 4.13). 

Dichlorobenzene, nitration to yield l,3-dinitro-4,6-dichlorobei zene, 96 Diethyl acetauidoualonate, 21 Diethyl acetylenedicarboxylate as di-eneophile, 86, 87... 

The observation of nitration in nitromethane fully dependent on the first power of the concentration of aromatic was made later. The rate of reaction of /)-dichlorobenzene ([aromatic] = 0-2 mol [HNO3] = 8-5 mol 1 ) obeyed such a law. The fact that in a similar solution 1,2,4-trichlorobenzene underwent reaction according to the same kinetic law, but about ten times slower, shows that under first-order conditions the rate of reaction depends on the reactivity of the compound. 

In acetic acid the rates of nitration of chlorobenzene and bromo-benzene were fairly close to being first order in the concentration of aromatic, and nitration fully according to a first-order law was observed with O, m-, and/i-dichlorobenzene, ethyl benzoate and 1,2,4-trichloro-benzene. 

Using the partial rate factors for nitration of chlorobenzene, Ridd and de la Mare calculated the relative rates of nitration of the dichlorobenzenes, with respect to /)-dichlorobenzene, with the results shown below. Also given are results based on more recent nitrations in mixed... 

Nitrated monochlorobenzene is used as a building block to produce many other products. There is also some commercial nitration of o-dichlorobenzene in the United States and Western Europe. 

A. 1,3-Dinitro-4,6-dichlorobenzene (Caution Note 1). To a well-stirred solution of 140 g. (1.386 moles) of potassium nitrate in 500 ml. of concentrated sulfuric acid is added 100.0 g. (0.680 mole) of w-dichlorobenzene in one portion. I he temperature of the reaction mixture rises during a few minutes to 135 140°, then... 

The kinetic effect of increased pressure is also in agreement with the proposed mechanism. A pressure of 2000 atm increased the first-order rates of nitration of toluene in acetic acid at 20 °C and in nitromethane at 0 °C by a factor of about 2, and increased the rates of the zeroth-order nitrations of p-dichlorobenzene in nitromethane at 0 °C and of chlorobenzene and benzene in acetic acid at 0 °C by a factor of about 559. The products of the equilibrium (21a) have a smaller volume than the reactants and hence an increase in pressure speeds up the rate by increasing the formation of H2NO. Likewise, the heterolysis of the nitric acidium ion in equilibrium (22) and the reaction of the nitronium ion with the aromatic are processes both of which have a volume decrease, consequently the first-order reactions are also speeded up and to a greater extent than the zeroth-order reactions. 

The tetraazapentalene ring system forms the core of the thermally insensitive explosive TACOT (Section 7.10) and so its fusion with the furoxan ring would be expected to enhance thermal stability and lead to energetic compounds with a high density, y-DBBD (95) is prepared from the nitration of tetraazapentalene (91), nucleophilic displacement of the o-nitro groups with azide anion, further nitration to (94), followed by furoxan formation on heating in o-dichlorobenzene at reflux. The isomeric explosive z-DBBD (96) has been prepared via a similar route. ... 

Hydroxy and Amino Compounds, Explosives from. A number of commercially available amino alcohols have been condensed with 2,4-dichlorobenzene to give products which, when nitrated, are explosive. Products from the nitration of several glycerol derivs, guanidine derivs phenylbenzotriazole derivs were also studied. Prepn of the following compds their props are reported ... 

Dinitro-3,4-dichlorobenzene, ndls (from petr eth), mp 97° can be prepd by diazotizing with NaN02 2-nitro-5,6-dichloroaniline (Ref 1) lt2-Diniiro-3, wdichlurobenzen , crysts (from ale +benz), mp 95 98° obtd by nitrating with mixed acids l-nitro-3,5-dichlorobenzene (Ref 2)... 

Dinitro-4,5-dichlorobenzene, crysts (from dil acetic acid), mpl07°or pits (from ale), mp 109 10° prepd by nitrating with mixed acids at 100° l-nitro-3,4-dichlorobenzene (Ref 3)... 

Dinitro-2,4-dichlorobenzene, ndls or prisms (from ale), mp 70-7 1° prepd by nitrating l-nitro-2,6-dichlorobenzene (Ref 4)... 

Dimtro-2,5-dichlorobenzene, Ifts (from ale) or monoclinic prisms (from CCI4), mp 104-05°, bp 302°(dec), d 1,7103 at 16° was prepd by nitrating l-nitco-2,5 dichlorobenzene (Ref 5) an expl compd proposed for use in mixts with PA... 

Dinitro-2,5-d(chlorobenzene, citron-yel crysts (from chlf) or It-yel ndls (from ale), mp 117.5-19°, bp 304° obtd with other isomers on nitrating 1,4-dichlorobenzene (Ref 9)... 

The reaction of 3-phenyloxetane (10) with nitric acid in dichloromethane and trichloromethane under anhydrous conditions has been investigated.35 Quantitative conversion into 2-(nitrophenyl)propane-l,3-diol dinitrates occurs. The substrate reacts through its majority hydrogen-bonded complexed form initially by a mixture of aromatic nitration and oxetane ring opening. The nitration, perhaps surprisingly, proceeds at a rate comparable to that of / -dichlorobenzene. 

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