Packaging and storage—
Preserve in tight containers, and avoid exposure to excessive heat.
Identification—
It is readily volatilized even at low temperatures and is flammable; when burned, a yellow flame and an acetous odor are produced.
Acidity—
A solution of 2.0 mL in 10 mL of neutralized alcohol requires not more than 0.10 mL of 0.10 N sodium hydroxide for neutralization, 2 drops of
phenolphthalein TS being used as the indicator.
Limit of nonvolatile residue—
Evaporate it in a tared porcelain dish on a steam bath, and dry at 105
for 1 hour: not more than 0.02% of residue remains.
Limit of methyl compounds—
Place 20 mL in a 500-mL separator, add a solution of 20 g of sodium hydroxide in 50 mL of water, insert the stopper in the separator, and wrap it securely in a towel for protection against the heat of the reaction. Shake the mixture vigorously for about 5 minutes, cautiously opening the stopcock from time to time to permit the escape of air. Continue shaking vigorously until a homogeneous liquid results, then distill, and collect about 25 mL of the distillate. To 0.05 mL of the distillate add 1 drop of dilute phosphoric acid (1 in 20) and 1 drop of potassium permanganate solution (1 in 20). Mix, allow to stand for 1 minute, and add sodium bisulfite solution (1 in 20), dropwise, until the permanganate color is discharged. If a brown color remains, add 1 drop of the dilute phosphoric acid. To the colorless solution add 5 mL of freshly prepared
chromotropic acid TS, and heat on a steam bath at 60
for 10 minutes: no violet color appears.
Chromatographic purity—
Chromatographic system (see Chromatography 
621
)—
The gas chromatograph is equipped with a flame-ionization detector and a 1.8-m × 4-mm column that contains support S11. The column temperature is maintained at 115
for 6 minutes, then programmed to rise at 16
per minute to 200
, and held at 200
for 15 minutes. Prepare a mixture of chloroform, ethyl acetate, isobutyl acetate, and
n-butyl acetate (3:1:1:1), and inject 0.1 µL, using a 1-µL syringe, into the chromatograph. In the resulting chromatogram, the retention times, relative to ethyl acetate as 1.0, are about 0.9 for chloroform, 2.7 for isobutyl acetate, and 2.8 for
n-butyl acetate; and the tailing factor,
T, for the ethyl acetate peak is not more than 1.5; the resolution,
R, between the chloroform and ethyl acetate peaks is not less than 1.3, and the resolution,
R, between the isobutyl acetate and
n-butyl acetate peaks is not less than 1.5.
Procedure—
Using a 1-µL syringe, inject a suitable volume (about 0.06 µL) of Ethyl Acetate into the chromatograph, record the chromatogram, and measure the areas of all the peaks. The area of the ethyl acetate peak is not less than 99.5% of the sum of the areas of all the peaks.
Organic volatile impurities, Method I 467:
meets the requirements, the following modifications to the
Chromatographic System being made. The gas chromatograph contains a 0.53-mm × 30-m fused-silica analytical column coated with a 1-µm G16 stationary phase; the carrier gas has a linear velocity of about 10 cm per second; and the makeup gas, nitrogen, has a flow rate of about 30 mL per minute. The column temperature is programmed according to the following steps: it is maintained at 50
for 12 minutes, then increased to 175
at a rate of 8
per minute, followed by an increase to 230
at a rate of 35
per minute, and maintained for at least 16 minutes.
Assay—
Transfer about 1.5 g of Ethyl Acetate, accurately weighed in a tared, stoppered weighing bottle, to a suitable flask, add 50.0 mL of 0.5 N sodium hydroxide VS, and heat on a steam bath under a reflux condenser for 1 hour. Allow to cool, add phenolphthalein TS, and titrate the excess sodium hydroxide with 0.5 N hydrochloric acid VS. Perform a blank determination (see
Residual Titrations under
Titrimetry 541). Each mL of 0.5 N sodium hydroxide is equivalent to 44.05 mg of C
4H
8O
2.
;)
