In a flask cooled in an ice bath are mixed 425 g. (300 cc., 4.7 moles) of c.p. nitrous-free, concentrated nitric acid (sp. gr. 1.42) (Note 1) and 550 g. (300 cc.) of c.p. concentrated sulfuric acid (sp. gr. 1.84). In a second flask, also cooled in an ice bath, 92 g. (50 cc.) of c.p. concentrated sulfuric acid is added to 119 g. (150 cc., 3.7 moles) of pure methyl alcohol (Note 2) while the temperature is maintained below 10°.

One-third of the cold nitric-sulfuric mixture is placed in each of three 500-cc. Erlenmeyer flasks (Note 3), and each portion is treated separately with one-third of the methyl alcohol-sulfuric acid mixture, with constant shaking and thorough mixing (Note 4). The temperature is allowed to rise fairly rapidly to 40° and kept at this point by external cooling. During the addition of the methyl alcohol-sulfuric acid, most of the ester separates as an almost colorless oily layer above the acid. The time required for completion of the reaction is two to three minutes for each flask. The reaction mixtures are allowed to stand in the cold for an additional fifteen minutes but not longer. The lower layer of spent acid is separated promptly and poured at once into a large volume of cold water (about 1 l. for each portion) to avoid decomposition which quickly ensues with copious evolution of nitrous fumes.

The combined ester layers are washed with two 25-cc. portions of ice-cold salt solution (sp. gr. 1.17) (Note 5). A small quantity (8–10 drops) of concentrated sodium hydroxide solution is added to the second wash liquid until it has a faintly alkaline reaction to litmus. The ester is washed free of alkali with ice-cold salt solution and finally washed with two 15-cc. portions of ice water (Note 6). The product is treated with 10–15 g. of anhydrous calcium chloride and allowed to stand with occasional shaking for an hour at 0°. It is then decanted onto a fresh 5-g. portion of the drying agent and after standing for one-half hour is filtered. The crude ester without further purification (Note 7) may be used directly for most synthetic purposes, such as the preparation of phenylnitromethane (p. 512). The yield is 190–230 g. (66–80 per cent of the theoretical amount). The crude ester should be used promptly and not stored.