Ethyl Acetate
(eth' il as' e tate).
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C4H8O2 88.11
Acetic acid, ethyl ester;    
Ethyl acetate     [141-78-6].
Ethyl Acetate contains NLT 99.0% and NMT 100.5% of ethyl acetate (C4H8O2).
•  A. It is readily volatilized, even at low temperatures, and is flammable. When burned, a yellow flame and acetous odor are produced.
•  Procedure
Sample:  Weigh 1.5 g of Ethyl Acetate in a stoppered weighing bottle.
Titrimetric system 
Mode:  Residual titration
Titrant:  0.5 N sodium hydroxide VS
Back-titrant:  0.5 N hydrochloric acid VS
Blank:  50 mL of 0.5 N sodium hydroxide VS, accurately measured
Endpoint detection:  Visual
Analysis:  Transfer the Sample 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 h. Allow to cool, and add phenolphthalein TS. Titrate the excess sodium hydroxide with 0.5 N hydrochloric acid VS. Perform a blank determination.
Calculate the percentage of ethyl acetate (C4H8O2) in the Sample taken:
Result = {[(VB VS) × N × F ]/W} × 100
VB== Back-titrant volume consumed by the Blank (mL)
VS== Back-titrant volume consumed by the Sample (mL)
N== actual normality of the Back-titrant (mEq/mL)
F== equivalency factor for ethyl acetate, 88.1 mg/mEq
W== Sample weight (mg)
Acceptance criteria:  99.0%–100.5%
•  Limit of Nonvolatile Residue
Sample:  Ethyl Acetate
Analysis:  Evaporate the Sample in a tared porcelain dish on a steam bath, and dry at 105 for 1 h.
Acceptance criteria:  NMT 0.02%
•  Limit of Methyl Compounds
Sample:  20 mL of Ethyl Acetate
Analysis:  Place the Sample in a 500-mL separator. Add a solution of 20 g of sodium hydroxide in 50 mL of water, and insert the stopper in the separator. Wrap it securely in a towel for protection against the heat of the reaction. Shake the mixture vigorously for about 5 min, 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 min, 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 min.
Acceptance criteria:  No violet color appears.
•  Chromatographic Purity
System suitability solution:  Chloroform, ethyl acetate, isobutyl acetate, and n-butyl acetate (3:1:1:1)
Chromatographic system 
Mode:  GC
Detector:  Flame ionization
Column:  1.8-m × 4-mm; support S11
Column temperature:  See Table 1.
Table 1
Hold Time
at Final
115 115 6
115 16 200 15
System suitability 
Sample:  0.1 µL of System suitability solution
[Note—The retention times for chloroform, isobutyl acetate, and n-butyl are 0.9, 2.7, and 2.8, respectively, relative to ethyl acetate as 1.0. ]
Suitability requirements 
Resolution:  NLT 1.3 between the chloroform and ethyl acetate peaks; NLT 1.5 between the isobutyl acetate and n-butyl acetate peaks
Tailing factor:  NMT 1.5 for the ethyl acetate peak
Sample:  Ethyl Acetate (neat)
Inject about 0.06 µL using a 1-µL syringe.
Acceptance criteria:  The area of the ethyl acetate peak is NLT 99.5% of the sum of the areas of all the peaks.
•  Acidity
Sample solution:  2.0 mL of Ethyl Acetate in 10 mL of neutralized alcohol
Analysis:  Add 2 drops of phenolphthalein TS to the Sample solution. Neutralize with 0.10 N sodium hydroxide.
Acceptance criteria:  NMT 0.10 mL of 0.10 N sodium hydroxide is required.
•  Readily Carbonizable Substances Test 271
Sample:  2 mL of Ethyl Acetate
Analysis:  Add the Sample carefully to 10 mL of sulfuric acid to form separate layers.
Acceptance criteria:  No dark zone is developed within 15 min.
•  Specific Gravity 841: 0.894–0.898
•  Packaging and Storage: Preserve in tight containers, and avoid exposure to excessive heat.
Auxiliary Information— Please check for your question in the FAQs before contacting USP.
Topic/Question Contact Expert Committee
Monograph Robert H. Lafaver, M.S.
Scientific Liaison
(EXC2010) Monographs - Excipients
USP35–NF30 Page 1792
Pharmacopeial Forum: Volume No. 34(5) Page 1223