Phenyltrimethylammonium sulfomethylate

B. Phenyltrimethylammonium Tribromide. A solution of 10 g. (0.04 mole) of phenyltrimethylammonium sulfomethylate in 10 ml. of aqueous 48% hydrobromic acid diluted with 10 ml. of water is prepared in a 125-ml. Erlenmeyer flask equipped with a magnetic stirrer. Bromine (2.5 ml.) (Note 5) is added to the stirred solution from a dropping funnel in about 20 minutes. An orange-yellow precipitate forms immediately and the slurry is stirred at room temperature for 5-6 hours. The product, phenyltrimethylammonium tribromide (PTT) is filtered, washed with about 10 ml. of water and air-dried under an efficient hood. The crude PTT, ca. 15 g., is recrystallized from 25 ml. of acetic acid to give, after filtration and air-drying, 12.9-14.0 g. (86-93%) (Note 6) of orange crystals, m.p. 113— 115°. 

In a 250-ml. wide-necked flask equipped with a thermometer. 26 ml. (0.2 mole) of freshly distilled dimethylaniline (b.p. 78°/l3 mm.) is dissolved in 100 ml. of toluene. The mixture is healed under magnetic stirring to about 40°, and 19 ml. (0.2 mole) of distilled dimethyl sulfate is added through a funnel in about 20 min. After a few minutes the colorless. sulfomethylate starts to crystallize. The temperature varies very little during the addition but rises slowly for I hr. until it reaches about 50°. One and a half hours after the end of the addition the mixture is heated on a steam bath for I hr. After cooling, the phenyltrimethylammonium sulfomethylate is collected, washed with 20 ml. of toluene, and dried under vacuum yield 47.5 g. (96%). ... 

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