Paraffin
»Paraffin is a purified mixture of solid hydrocarbons obtained from petroleum.
Packaging and storage—
Preserve in well-closed containers,and avoid exposure to excessive heat.
Identification—
A:
When strongly heated,it ignites with a luminous flame and deposits carbon.
B:
Heat about 500mg in a dry test tube with an equal weight of sulfur:the mixture evolves hydrogen sulfide and becomes black as a result of the liberation of carbon.
Reaction—
Shake melted Paraffin with an equal volume of hot alcohol previously neutralized to litmus:the separated alcohol is neutral to litmus.
Readily carbonizable substances á271ñ—
Use a clean,dry,heat-resistant,glass-stoppered test tube,140±3mm in length and 14±1mm in diameter,with a capacity of 16±1mLwhen the stopper is inserted,and calibrated at the 5-and 10-mLliquid levels.Place in the test tube 5mLof Paraffin,at a temperature just above the melting point,add 5mLof sulfuric acid containing 94.5%to 94.9%of H2SO4,and heat in a water bath at 70
for 10minutes.When 5minutes have elapsed,and at each successive minute thereafter,remove the tube from the bath,place a finger over the stopper,and give the tube three vigorous vertical shakes over an amplitude of about 12cm,returning the tube to the bath within 3seconds after the time when it was removed therefrom.At the end of 10minutes from the time the tube was placed in the bath,the acid has no more color than a mixture of 3mLof ferric chloride CS,1.5mLof cobaltous chloride CS,and 0.50mLof cupric sulfate CS,overlaid with 5mLof mineral oil.If the sulfuric acid remains dispersed in the molten paraffin,the color of the emulsion is not darker than that of the standard mixture when shaken vigorously.
for 10minutes.When 5minutes have elapsed,and at each successive minute thereafter,remove the tube from the bath,place a finger over the stopper,and give the tube three vigorous vertical shakes over an amplitude of about 12cm,returning the tube to the bath within 3seconds after the time when it was removed therefrom.At the end of 10minutes from the time the tube was placed in the bath,the acid has no more color than a mixture of 3mLof ferric chloride CS,1.5mLof cobaltous chloride CS,and 0.50mLof cupric sulfate CS,overlaid with 5mLof mineral oil.If the sulfuric acid remains dispersed in the molten paraffin,the color of the emulsion is not darker than that of the standard mixture when shaken vigorously.
Auxiliary Information—
Staff Liaison:Catherine Sheehan,B.Sc.,Scientist
Expert Committee:(EMC)Excipients:Monograph Content
USP28–NF23Page 3045
Phone Number:1-301-816-8262