Methyl »m-Nitrobenzoate

Methyl m-nitrobenzoate. In a 1 htre round-bottomed or bolt-head flask, fitted with a mechanical stirrer, place 102 g. (94 ml.) of pure methyl benzoate (Section IV,176) support a separatory funnel containing a mixture of 62 -5 ml, of concentrated sulphuric acid and 62 -5 ml. of concentrated nitric acid over the mouth of the flask. Cool the flask in an ice bath to 0-10°, and then run in the nitrating mixture, with stirring. 

Hydrolysis of methyl m-nitrobenzoate to m-nitrobenzoic acid. Place 90 -5 g. of methyl m-nitrobenzoate and a solution of 40 g. of sodium hydroxide in 160 ml. of water in a 1-htre round-bottomed flask equipped with a reflux condenser. Heat the mixture to boiling during 5-10 minutes or until the ester has disappeared. Dilute the reaction mixture with an equal volume of water. When cold pour the diluted reaction product, with vigorous stirring, into 125 ml. of concentrated hydrochloric acid. Allow to cool to room temperature, filter the crude acid at the pump and wash it with a httle water. Upon drying at 100°, the crude m-nitrobenzoic acid, which has a pale brownish colour, weighs 80 g. and melts at 140°, Recrystalhsation from 1 per cent, hydrochloric acid afibrds the pure acid, m.p. 141°, as a pale cream sohd the loss of material is about 5 per cent. 

The preparation of a number of miscellaneous acids is described. m-Nitrobenzoic acid. Although m-nitrobenzoio 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 m-nitrobenzoate, which is easily obtained in a pure condition ... 

Methyl l>cnzoate Methyl m-nitrobenzoate m-Nitrobeiizoic acid... 

After the nitric acid has been added, stirring is continued for fifteen minutes longer the mixture is then poured upon 1300 g. of cracked ice. The crude methyl m-nitrobenzoate separates as a solid and is filtered off by means of suction and washed with water. The product is placed in a flask and agitated with 200 cc. of ice-cold methyl alcohol in order to remove a small amount of o-nitrobenzoic ester and other impurities that are present. The cooled mixture is then filtered by means of suction, washed with another 100-cc. portion of cold methyl alcohol (Note 3), and the solid dried. Flic yield is 220-230 g. (81-85 Per cent of the theoretical amount) of an almost colorless product melting at 74-76°. In order to obtain a product of maximum purity, which melts at 78°, it is advisable to rccrystallize the ester from an equal weight of methyl alcohol,... 

Methyl m-nitrobenzoate has been prepared by the esterification of m-nitrobenzoic acid 1 this method is, however, obviously much less satisfactory than nitration of methyl benzoate. Nitration by means of fuming nitric acid has also been applied to methyl benzoate,2 but the use of the ordinary nitration mixture of concentrated sulfuric add and concentrated nitric acid is more satisfactory. 

In a 2-1. round-bottom flask fitted with a reflux condenser are placed a solution of 80 g. (2 mols) of sodium hydroxide in 320 cc. of water (Note 1) and 180 g. (1 mol.) of methyl m-nitrobenzoate (not recrystallized, p. 71). The mixture is heated to boiling during five to ten minutes or until the saponification is complete as shown by the disappearance of the ester. 

After the hydrolysis of the methyl m-nitrobenzoate it is essential that the solution of the sodium salt be poured into the acid. If acid be added to the salt in the usual way, a less soluble acid salt separates and as this cannot be entirely removed from the w-nitrobenzoic acid even on long digestion with hydrochloric acid, a product is obtained which does not dissolve completely in ether. 

Ethyl o-nitrobenzoate Methyl o-nitrobenzoate Ethyl m-nitrobenzoate Methyl m-nitrobenzoate Ethyl p-nitrobenzoate Methyl p-nitrobenzoate... 

Fig. 12. Eyring plots for the quenching of Ru(bpy)f+ by 1,4-naphthoquinone (a), duroqui-none (b), and methyl m-nitrobenzoate (c) in acetonitrile...

Methylene iodide, I, 57-59 /3-Methyl esculetin, IV, 45-46 (//-Methyl ethyl acetic acid, V, 75-77 Methyl formate, III, 67 Methyl hexyl carbinol, I, 61-66 Methyl iodide, I, 57, 59 5-Methyl isatin, V, 74 Methyl o-nitrobenzoate, III, 72 Methyl m-nitrobenzoate, III, 71-72, 73-Methyl oxalate, V, 60 Methyl Red, II, 47-51... 

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