Diethyl Phthalate
(dye eth' il thal' ate).
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C12H14O4 222.24

1,2-Benzenedicarboxylic acid, diethyl ester.
Diethyl phthalate [84-66-2].
» Diethyl Phthalate contains not less than 98.0 percent and not more than 102.0 percent of C12H14O4, calculated on the anhydrous basis.
[Caution—Avoid contact. ]
Packaging and storage— Preserve in tight containers.
USP Reference standards 11
USP Diethyl Phthalate RS
Identification, Infrared Absorption 197F, on undried specimen.
Specific gravity 841: between 1.118 and 1.122, at 20.
Refractive index 831: between 1.500 and 1.505, at 20.
Acidity— Mix 20.0 g with 50 mL of alcohol that previously has been neutralized to a phenolphthalein endpoint, and titrate with 0.10 N sodium hydroxide to a phenolphthalein endpoint: not more than 0.50 mL is required for neutralization.
Water, Method I 921: not more than 0.2%.
Residue on ignition 281 Heat gently about 10 g, accurately weighed, until the liquid has evaporated, and ignite the residue to constant weight. Not more than 0.02% is found.
Assay— Transfer about 1.5 g of Diethyl Phthalate, accurately weighed, to a flask, add 50.0 mL of 0.5 N alcoholic potassium hydroxide VS, attach a reflux condenser to the flask, and boil on a water bath for 1 hour. Add 20 mL of water, then add phenolphthalein TS, and titrate the excess potassium hydroxide with 0.5 N hydrochloric acid VS. Perform a blank determination (see Residual Titrations under Titrimetry 541). Each mL of 0.5 N potassium hydroxide is equivalent to 55.56 mg of C12H14O4.
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USP35–NF30 Page 1784