When the addition of the
nitric acid solution is complete, the reaction mixture is removed from the
ice bath and allowed to stand at room temperature for two hours. The flask is then warmed, with shaking, to 50° on a
water bath (Note
3) and maintained at that temperature for ten minutes. The cooled reactants are then poured slowly into 800 cc. of ice water and well stirred. About
40 g. of sodium chloride is added, and the aqueous layer is decanted and extracted with
200–250 cc. of a commercial grade of ether. The ethereal extract is added to the residual
nitromesitylene, and this ethereal solution is washed with three or four
30-cc. portions of a 10–15 per cent sodium hydroxide solution until the water extract is distinctly alkaline. The
ether is then distilled from a
steam bath. The residue, after the addition of about
150 cc. of 10 per cent sodium hydroxide solution, is steam-distilled until a test sample of the distillate is clear and free of oil drops. The steam distillation requires about three hours, during which time 1.5 l. of distillate is collected. The
nitromesitylene settles to the bottom of the distillate. The water is decanted through a
filter paper, and the residue is dissolved in
30 cc. of ether. The filter paper, if it contains any solid particles, is washed with
10 cc. of ether, and the two fractions are combined and placed in a
150-cc. distilling flask with a
water-cooled receiver. After removal of the
ether on a steam bath, the yellow residue is distilled with a free flame. All but 0.5 to 1.5 g. of material distils at
243–250°, and the distillate, which weighs
47 g., solidifies on cooling. The yellow crystalline product is purified by dissolving in
25 cc. of commercial methyl alcohol and cooling with stirring in a
bath of ice and salt. The crystals are then filtered on a
small Büchner funnel and washed twice with
5-cc. portions of cold methyl alcohol. From the wash alcohol, by exactly the same procedure, there is obtained
6–8 g. of crude crystals boiling at
243–249°. This material yields on crystallization
4 g. of pure
nitromesitylene. The pure
nitromesitylene, which has a light yellow color, melts at
43–44°. The yield is
41–42 g. (
74–76 per cent of the theoretical amount).