Preparation nitrobenzenes

The reduction is similar to that of nitrobenzene (Preparation 359), but no condenser need be used in this case. 120 gms. iron powder and 60... 

Beilstein and Kuhlberg. .. in 1870. However, it may be that dinitrobenzene , m.p. 71°C obtained in 1841 by St. Claire-Deville. .. by the nitration of nitrobenzene prepared from light... 

Dinitrotoluene (2,4-) was first obtained by Beilstein andKuhlberg [21] in 1870. However, it may be that dinitrobenzene , m.p. 71°C obtained in 1841 by St. Claire Deville [25] by the nitration of nitrobenzene prepared from light oil, was in fact dinitrotoluene. As Rosensriel [26] found in 1872 p- nitrotoluene yields only one product of dinitration, viz. the 2,4-isomer, while o- nitrotoluene gives in addition another isomer, the structure of which he did not determine. 

Nitrobenzene Physical properties Chemical properties Toxicity of nitrobenzene Preparation of nitrobenzene Diniirobenzcnes Physical properties Chemical properties Toxicity of dinitrohenzenes Explosive properties of diniirobenzene Sensitivity to impact Preparation of dinitrohenzenes Nitration in two stages in two niirators Purification... 

Dibr omo- 5 - nitrobenzene [prepared from j -nitroaniline as in part (c)]... 

Fig. 7.3 Aniline chemical synthesis, (a) nitrobenzene, prepared from benzene with nitric acid by electrophUic substitution reaction and further treatment with niquel at 600 °C or (b) from chlorobenzene by heating with ammonia in the presence of a copper catalyst...

It is prepared by reduction of nitrobenzene with iron and NaOH. It is also prepared by an electrolytic reduction of nitrobenzene. It is widely used for the preparation of benzidine. 

Crystalline powder, m.p. 174-179 C. Prepared by treatment of thiocarbanilide with sulphur, or by heating aniline, carbon disulphide and nitrobenzene. It is an important rubber accelerator, and on oxidation gives dibenzthiazyl disulphide, also a rubber accelerator. 

CijHgNj. Made by heating o-pheny-lenediamine with glycerol, nitrobenzene and cone, sulphuric acid. It exists as a monohydrate, m.p. 94" C, or anhydrous, m.p. 117°C. It is used as a complexing reagent in the estimation of Fe and in the preparation of numer-... 

Occurs in the high-boiling fraction of coal tar. Most conveniently prepared by Skraup s reaction by healing a mixture of aniline, glycerol, sulphuric acid and nitrobenzene. Used in the manufacture of dyestuffs, and pharmaceutical products. 

Nitrobenzene is a pale yellow liquid, having a b.p. 210 , and dy 1 20. It has an odour which is similar to that of almonds, and which is therefore often confused with that of benzaldehyde. Nitrobenzene is used chiefly for the preparation of aniline. 

Azoxybenzene is readily prepared by reduction of nitrobenzene in an alkaline medium with dextrose or sodium arsenite ... 

The commercial product, m.p. 53-55°, may be used. Alternatively the methyl -naphthyl ketone may be prepared from naphthalene as described in Section IV,136. The Friedel - Crafts reaction in nitrobenzene solution yields about 90 per cent, of the p-ketone and 10 per cent, of the a-ketone in carbon disulphide solution at — 15°, the proportions ore 65 per cent, of the a- and 35 per cent, of the p-isomer. With chlorobenzene ns the reaction medium, a high proportion of the a-ketone is also formed. Separation of the liquid a-isomer from the solid p-isomer in Such mixtures (which remain liquid at the ordinary temp>erature) is readily effected through the picrates the picrate of the liquid a-aceto compound is less soluble and the higher melting. 

Quinoline may be prepared by heating a mixture of aniline, anhydrous glycerol and concentrated sulphuric acid with an oxidising agent, such as nitrobenzene. The reaction with nitrobenzene alone may proceed with extreme violence, but by the addition of ferrous sulphate, which appears to function as an oxygen carrier, the reaction is extended over a longer period of time and Is under complete control. 

The first nitration to be reported was that of beri2ene itself. Mitscher-lich in 1834 prepared nitrobenzene by treating benzene with fuming nitric acid. Not long afterwards the important method of effecting nitration with a mixture of nitric and sulphuric acids ( mixed acid ) was introduced, evidently in a patent by Mansfield the poor quality of early nitric acid was probably the reason why the method was developed. Since these beginnings, nitration has been the subject of continuous study. 

Solutions of dinitrogen pentoxide have been used in preparative nitrations.Benzene, bromobenzene, and toluene were nitrated rapidly in solutions of the pentoxide in carbon tetrachloride nitrobenzene could not be nitrated under similar conditions, but reacted violently with solid dinitrogen pentoxide. 

Cumene (isopropylbenzene) is a relatively inexpensive com mercially available starting material Show how you could prepare m-isopropyl nitrobenzene from cumene... 

Ha.loisoquinolines, The Sandmeyer reaction is commonly used to prepare chloroisoquinolines from the amino compound. The corresponding hydroxy compounds are also used by treatment with chlorides of phosphoms. The addition of bromine to a slurry of isoquinoline hydrochloride in nitrobenzene gives a 70—80% yield of 4-bromoisoquinoline [1532-97-4J. Heating 1-chloroisoquinoline [19493-44-8] with sodium iodide andhydriodic acid gives 1-iodoisoquinoline [19658-77-6] (179). 

In a variation of this method, isolation of the ben2hydrol derivative is not required. The methane base undergoes oxidative condensation in the presence of acid with the same or a different arylamine direcdy to the dye. New fuchsine [3248-91 -7] Cl Basic Violet 2 (16), is prepared by condensation of two moles of o-toluidine with formaldehyde in nitrobenzene in the presence of iron salts to give the corresponding substituted diphenylmethane base. This base is also not isolated, but undergoes an oxidative condensation with another mole of o-toluidine to produce the dye. 

Nitration of benzene yields nitrobenzene, which is reduced to aniline, an important intermediate for dyes and pharmaceuticals. Benzene is chlorinated to produce chlorobenzene, which finds use in the preparation of pesticides, solvents, and dyes. 

Production of cellulose esters from aromatic acids has not been commercialized because of unfavorable economics. These esters are usually prepared from highly reactive regenerated cellulose, and their physical properties do not differ markedly from cellulose esters prepared from the more readily available aHphatic acids. Benzoate esters have been prepared from regenerated cellulose with benzoyl chloride in pyridine—nitrobenzene (27) or benzene (28). These benzoate esters are soluble in common organic solvents such as acetone or chloroform. Benzoate esters, as well as the nitrochloro-, and methoxy-substituted benzoates, have been prepared from cellulose with the appropriate aromatic acid and chloroacetic anhydride as the impelling agent and magnesium perchlorate as the catalyst (29). 

Diaminoanthraquinone is an important intermediate for vat dyes and disperse dyes, and is prepared by oxidizing leuco-l,4-diaminoanthraquinone with nitrobenzene in the presence of piperidine. An improved process has been reported (45). 

Phenazine mono-N-oxides have also been prepared from nitrobenzene derivatives. Condensation of nitrobenzene with aniline using dry NaOH at 120-130 °C results in modest yields of phenazine 5-oxide, although the precise mechanism of this reaction is not well understood (57HC(ll)l) with unsymmetrical substrates it is not possible to predict which of the isomeric fV-oxides will be produced. Nitrosobenzene derivatives also function as a source of phenazine mono-fV-oxides thus, if 4-chloronitrosobenzene is treated with sulfuric acid in acetic acid at 20 °C the fV-oxide is formed (Scheme 21). 

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