Phenol
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Phenol.
Phenol [108-95-2].
»Phenol contains not less than 99.0percent and not more than 100.5percent of C6H6O,calculated on the anhydrous basis.It may contain a suitable stabilizer.
Caution—Avoid contact with skin,since serious burns may result.
Packaging and storage—
Preserve in tight,light-resistant containers.
Labeling—
Label it to indicate the name and amount of any substance added as a stabilizer.
Clarity of solution and reaction—
Asolution (1in 15)is clear,and is neutral or acid to litmus paper.
Identification—
A:
To a solution add bromine TS:a white precipitate is formed,and it dissolves at first but becomes permanent as more of the reagent is added.
B:
To 10mLof a solution (1in 100)add 1drop of ferric chloride TS:a violet color is produced.
Congealing temperature á651ñ:
not lower than 39
.
.
Water,Method Iá921ñ:
not more than 0.5%.
Limit of nonvolatile residue—
Heat about 5g,accurately weighed,in a tared porcelain dish on a steam bath until it has evaporated,and dry the residue at 105for 1hour:not more than 0.05%of residue remains.
for 1hour:not more than 0.05%of residue remains.
Organic volatile impurities,Method Iá467ñ:
meets the requirements.
Assay—
Place about 2g of Phenol,accurately weighed,in a 1000-mLvolumetric flask,dilute with water to volume,and mix.Pipet 20mLof the solution into an iodine flask,add 30.0mLof 0.1Nbromine VS,then add 5mLof hydrochloric acid,and immediately insert the stopper.Shake the flask repeatedly during 30minutes,allow it to stand for 15minutes,add quickly 5mLof potassium iodide solution (1in 5),taking precautions against the escape of bromine vapor,and at once insert the stopper in the flask.Shake thoroughly,remove the stopper,and rinse it and the neck of the flask with a small quantity of water,so that the washing flows into the flask.Add 1mLof chloroform,shake the mixture,and titrate the liberated iodine with 0.1Nsodium thiosulfate VS,adding 3mLof starch TSas the endpoint is approached.Perform a blank determination (see Residual Titrationsunder Titrimetry á541ñ).Each mLof 0.1Nbromine is equivalent to 1.569mg of C6H6O.
Auxiliary Information—
Staff Liaison:Lawrence Evans,III,Ph.D.,Scientist
Expert Committee:(PA6)Pharmaceutical Analysis 6
USP28–NF23Page 1532
Phone Number:1-301-816-8389