Chlorocresol
;)
Phenol,4-chloro-3-methyl-.
4-Chloro-m-cresol [59-50-7].
»Chlorocresol contains not less than 99.0percent and not more than 101.0percent of C7H7ClO(4-chloro-3-methylphenol).
Packaging and storage—
Preserve in tight,light-resistant containers.
Completeness of solution—
Transfer 1g to a test tube,add 0.4mLof alcohol,and shake:solution is complete.
Identification—
A:
Add 40mg to 10mLof water,mix,and add 1drop of ferric chloride TS:a blue color develops.
B:
Transfer 50mg to a crucible,add 500mg of anhydrous sodium carbonate,and mix.Heat the mixture until fused.Cool,add 5mLof water,and boil.Acidify with 1mLof nitric acid,filter,and add 1mLof silver nitrate TSto the filtrate:a white precipitate is formed.
Limit of nonvolatile residue—
Heat about 1.0g,accurately weighed,in a tared crucible on a steam bath until it has evaporated,and dry the residue at 105
for 1hour:not more than 0.1%of residue remains.
for 1hour:not more than 0.1%of residue remains.
Assay—
Transfer about 70mg of Chlorocresol,accurately weighed,to an iodine flask,add 30mLof glacial acetic acid,25.0mLof 0.1Nbromine VS,10mLof potassium bromide solution (3in 20),and 10mLof hydrochloric acid.Immediately insert the stopper,mix,and allow to stand for 15minutes,protected from light.Quickly add 10mLof potassium iodide solution (1in 10)and 100mLof water,taking precautions against the escape of bromine vapor,at once insert the stopper,and shake the mixture 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 thoroughly,and titrate the liberated iodine with 0.1Nsodium thiosulfate VS,adding 3mLof starch TSas the endpoint is approached.Perform a blank determination (see Residual Titrations under Titrimetry á541ñ).Each mLof 0.1Nbromine is equivalent to 3.565mg of C7H7ClO.
Auxiliary Information—
Staff Liaison:Catherine Sheehan,B.Sc.,Scientist
Expert Committee:(EMC)Excipients:Monograph Content
USP28–NF23Page 2988
Phone Number:1-301-816-8262