Benzoic acid nitration

From Amino Benzoic Acid.—Amino acids by the diazo reaction and decomposition with water will yield the corresponding phenol acids. In such cases also if we start with benzoic acid, nitrate directly and reduce this to the amino compound, the final product of the diazo reaction will be the meta hydroxy acid. If we start with toluene and nitrate it and then proceed as in the foregoing and oxidize the amino toluene to amino benzoic acid our product will be the ortho and para hydroxy acids. 

It should be noted that aliphatic compounds (except the paraffins) are usually oxidised by concentrated nitric acid, whereas aromatic compounds (including the hydrocarbons) are usually nitrated by the concentrated acid (in the presence of sulphuric acid) and oxidised by the dilute acid. As an example of the latter, benzaldehyde, CjHsCHO, when treated with concentrated nitric acid gives ffi-nitrobenzaldehyde, N02CgH4CH0, but with dilute nitric acid gives benzoic acid, CgHgCOOH. 

Action of silver nitrate. Acidify 2 ml. of aqueous AgNOj solution with dil. HNO3 and add the acid chloride drop by drop with shaking. Acetyl chloride and benzoyl chloride give a precipitate of AgCl. Filter, wash with water, and then with methylated spirit to remove any benzoic acid the AgCl remains. 

The preparation of a number of miscellaneous acids is described. m-Nitrobenzoic acid. Although m-nitrobenzoic acid is the main product of the direct nitration of benzoic acid with potassium nitrate and concentrated sulphuric acid, the complete separation of the small quantity of the attendant para isomer is a laborious process. It is preferable to nitrate methyl benzoate and hydrolyse the resulting methyl w-nitrobenzoate, which is easily obtained in a pure condition ... 

Dinitrobenzoic acid. This acid may be prepared by the nitration of benzoic acid with a mixture of concentrated sulphuric acid and fuming nitric acid under special conditions (see also Section VII,22) ... 

Many aromatic compounds are sufficiently basic to be appreciably protonated in concentrated sulphuric acid. If nitration occurs substantially through the free base, then the reactivity of the conjugate acid will be negligible. Therefore, increasii the acidity of the medium will, by depleting the concentration of the free base, reduce the rateof reaction. This probably accounts for the particularly marked fall in rate which occurs in the nitration of anthraquinone, benzoic acid, benzenesulphonic acid, and some nitroanilines (see table 2.4). 

The kinetics of nitration of benzene in solutions at c. 20 °C in carbon tetrachloride have been investigated. In the presence of an excess of benzene (c. 2-4 mol 1 ) the rate was kinetically of the first order in the concentration of benzoyl nitrate. The rate of reaction was depressed by the addition of benzoic anhydride, provided that some benzoic acid was present. This result suggested that benzoyl nitrate itself was not responsible for the nitration, but generated dinitrogen pentoxide... 

Sahcylaldehyde is readily oxidized, however, to sahcyhc acid by reaction with solutions of potassium permanganate, or aqueous silver oxide suspension. 4-Hydroxybenzaldehyde can be oxidized to 4-hydroxybenzoic acid with aqueous silver nitrate (44). Organic peracids, in basic organic solvents, can also be used for these transformations into benzoic acids (45). Another type of oxidation is the reaction of sahcylaldehyde with alkaline potassium persulfate, which yields 2,5-dihydroxybenzaldehyde (46). 

Chlotobenzoyl)-benzoic acid is nitrated in concentrated sulfuric acid, then reduction of the nitro group, ring closure, and hydrolysis occur simultaneously in concentrated sulfuric acid in the presence of a reducing agent and boric acid. Thus obtained cmde chloro pink is purified by selective precipitation from sulfuric acid in order to separate it from by-produced 2-amino-3-chloto-l-hydroxyanthtaquinone (24) (36). 

Reactions.—i. Make a neutral solution of ammonium benzoate by adding excess of ammonia to benzoic acid and boiling until neutial. To different poitionsadd solutions of calcium chloi ide, ferric chloride, silver nitrate and lead acetate and note the results. 

Monoacyl Glycerol Nitrates. Formed by reacting in the liq phase at temps as high as 120, a mixt of glycide nitrate and an aliphatic carboxylic acid of the benzene series such as benzoic acid, with FeCl3 as catalyst. They were recommended as additives for NG, or like expls, to lower their freezing points Ref H. Jacobi W. Flemming, USP 2302324 (1942) CA 37, 2014 (1943)... 

Crude TNT produced by either batch or continuous methods requires purification. The ultimate objective of TNT purification is to remove all those products which are more reactive than TNT itself (isomers, nitrocresols, nitro-benzoic acids, etc), or which can easily give oily exudation products, such as isomers or lower nitrated substances... 

Prepn. Dissolve 2.4g of Pb nitrate in 50ml w at 90—95°, and add with stirring a coned soln of Na benzoate (prepd by neutralizing 2g of benzoic acid with 0.6g NaOH). Evaporate the mixt on a w bath to a small vol while the liq still remains clear. Cool and add 50ml of 95% ethanol. This results in a very fine, light yel ppt, which is separated by vacuum filtration. After drying at 50°, analysis gave 41.82% Pb and 3.40% water... 

Some interesting results have been obtained by Akand and Wyatt56 for the effect of added non-electrolytes upon the rates of nitration of benzenesulphonic acid and benzoic acid (as benzoic acidium ion in this medium) by nitric acid in sulphuric acid. Division of the rate coefficients obtained in the presence of nonelectrolyte by the concentration of benzenesulphonic acid gave rate coefficients which were, however, dependent upon the sulphonic acid concentration e.g. k2 was 0.183 at 0.075 molal, 0.078 at 0.25 molal and 0.166 at 0.75 molal (at 25 °C). With a constant concentration of non-electrolyte (sulphonic acid +, for example, 2, 4, 6-trinitrotoluene) the rate coefficients were then independent of the initial concentration of sulphonic acid and only dependent upon the total concentration of non-electrolyte. For nitration of benzoic acid a very much smaller effect was observed nitromethane and sulphuryl chloride had a similar effect upon the rate of nitration of benzenesulphonic acid. No explanation was offered for the phenomenon. 

Qian et al. [46] determined miconazole nitrate and benzoic acid in paint by a thin-layer chromatographic densitometric method. The drug was spotted on a GF254 silica gel plate, developed with a 42 21 13 5 w-hexane-chloroform-methanol-... 

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