C4H5NS 99.16

3-Isothiocyanato-1-propene.
Isothiocyanic acid allyl ester [57-06-7].

Packaging and storage— Preserve in tight containers.

Identification,Infrared Absorption á197Fñ— The spectrum exhibits pronounced peaks at about 700–cm,950–cm,980–cm,1300–cm,1340–cm,1350–cm,1410–cm,1420–cm,1650–cm,2100–cm,and 2200–cm.

Specific gravity á841ñ: between 1.013and 1.020.

Refractive index á831ñ: between 1.527and 1.531,determined at 20.

Distilling range,Method Iá721ñ: between 148and 154.

Limit of phenols— Dilute 1mLof it with 5mLof alcohol,and add 1drop of ferric chloride TS:a blue color is not produced immediately.

Assay— Transfer about 4mLof Allyl Isothiocyanate,accurately weighed,to a 100-mLvolumetric flask,add alcohol to volume,and mix.Transfer 5.0mLof this stock solution to a 100-mLconical flask,add 50.0mLof 0.1Nsilver nitrate VSand 5mLof ammonia TS.Connect the flask to a reflux condenser,heat on a water bath for 1hour,and allow to cool to room temperature.Disconnect the flask from the condenser,transfer the contents of the conical flask to a 100-mLvolumetric flask with the aid of water,dilute with water to volume,and mix.Pass through a dry filter,discarding the first 10mLof the filtrate.To 50.0mLof the subsequent filtrate add 5mLof nitric acid and 2mLof ferric ammonium sulfate TS,and titrate the excess silver nitrate with 0.1Nammonium thiocyanate VS.Perform a blank determination,using 5mLof alcohol in place of the stock solution,and make any necessary correction.Each mLof 0.1Nsilver nitrate is equivalent to 4.958mg of C4H5NS.

Expert Committee:(PA4)Pharmaceutical Analysis 4

USP28–NF23Page 68

Phone Number:1-301-816-8251