Ethyl Acetate
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C4H8O2 88.11
Acetic acid, ethyl ester.
Ethyl acetate [141-78-6].
» Ethyl Acetate contains not less than 99.0 percent and not more than 100.5 percent of C4H8O2.
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.
Specific gravity 841: between 0.894 and 0.898.
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.
Readily carbonizable substances 271 Pour 2 mL carefully upon 10 mL of sulfuric acid TS so as to form separate layers: no dark zone is developed within 15 minutes.
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.
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 C4H8O2.
Auxiliary Information— Please check for your question in the FAQs before contacting USP.
Topic/Question Contact Expert Committee
Monograph Robert H. Lafaver, B.A.
(EM105) Excipient Monographs 1
USP32–NF27 Page 1232
Pharmacopeial Forum: Volume No. 34(5) Page 1223
Chromatographic Column—
Chromatographic columns text is not derived from, and not part of, USP 32 or NF 27.