Potassium Permanganate
KMnO4
158.03
Permanganic acid (HMnO4),potassium salt.
Potassium permanganate (KMnO4) [7722-64-7].
»Potassium Permanganate contains not less than 99.0percent and not more than 100.5percent of KMnO4,calculated on the dried basis.
Caution—Observe great care in handling Potassium Permanganate,as dangerous explosions may occur if it is brought into contact with organic or other readily oxidizable substances,either in solution or in the dry state.
Packaging and storage—
Preserve in well-closed containers.
Identification—
Asolution of it is deep violet-red when concentrated and pink when highly diluted,and responds to the tests for Permanganate á191ñ.
Loss on drying á731ñ—
Dry it over silica gel for 18hours:it loses not more than 0.5%of its weight.
Insoluble substances—
Dissolve 2.0g in 150mLof water that previously has been warmed to steam-bath temperature,and filter immediately through a tared,medium-porosity filtering crucible.Wash the filter with three 50-mLportions of the warm water,and dry the filtering crucible and the residue at 105
for 3hours:not more than 4mg of residue is obtained (0.2%).
for 3hours:not more than 4mg of residue is obtained (0.2%).
Assay—
Transfer about 1000mg of Potassium Permanganate,accurately weighed,and for each mg of Potassium Permanganate taken,2.13mg of sodium oxalate,previously dried at 110to constant weight and accurately weighed,to a 500-mLconical flask.Add 150mLof water and 20mLof 7Nsulfuric acid,heat to about 80,and titrate the excess oxalic acid with 0.03Npotassium permanganate VS.Calculate the quantity,in mg,of KMnO4in the portion of Potassium Permanganate taken by the formula:
to constant weight and accurately weighed,to a 500-mLconical flask.Add 150mLof water and 20mLof 7Nsulfuric acid,heat to about 80,and titrate the excess oxalic acid with 0.03Npotassium permanganate VS.Calculate the quantity,in mg,of KMnO4in the portion of Potassium Permanganate taken by the formula:
0.4718WS-0.9482V,
in which 0.4718is the KMnO4equivalent,in mg,of each mg of sodium oxalate,WSis the weight,in mg,of sodium oxalate taken,0.9482is the quantity of KMnO4,in mg,in each mLof 0.03Npotassium permanganate,and Vis the volume,in mL,of 0.03Npotassium permanganate consumed.
Auxiliary Information—
Staff Liaison:Behnam Davani,Ph.D.,MBA,Senior Scientist
Expert Committee:(PA7)Pharmaceutical Analysis 7
USP28–NF23Page 1598
Phone Number:1-301-816-8394