Packaging and storage—
Preserve in well-closed containers.
Completeness and color of solution—
One g dissolves completely in 30 mL of alcohol and in 30 mL of ether, and the solutions are colorless.
Reaction—
Dissolve 1 g in 10 mL of neutralized alcohol: a clear solution results. Dilute this solution with 10 mL of water, and add 2 drops of phenolphthalein TS and 1 drop of 0.1 N sodium hydroxide: a red color is produced.
Loss on drying 
731
—
Dry it over phosphorus pentoxide for 3 hours: it loses not more than 1.0% of its weight.
Chloride—
To a solution of 200 mg in 10 mL of alcohol add 1 mL of 2 N nitric acid and a few drops of
silver nitrate TS: no opalescence is produced.
Assay—
Ferrocyphen indicator solution—
Dissolve, without warming, 0.5 g of ferrocyphen in 50 mL of sulfuric acid.
Procedure—
Dissolve about 400 mg of Butamben, previously dried and accurately weighed, in a mixture of 100 mL of water and 20 mL of hydrochloric acid. Add 1 mL of
Ferrocyphen indicator solution. Cool the solution in an ice bath to about 10
, and titrate with 0.1 M sodium nitrite VS to a violet endpoint that is stable for not less than three minutes. Perform a blank determination, and make any necessary correction. Each mL of 0.1 M sodium nitrite is equivalent to 19.32 mg of C
11H
15NO
2.
;)
