General Notices
C8H7N3O5 225.1 148-01-6
Definition Dinitolmide is 3,5-dinitro-o-toluamide. It contains not less than 98.0% and not more than 100.5% of C8H7N3O5, calculated with reference to the dried substance.
Characteristics A cream to light tan powder; odourless or almost odourless.
Practically insoluble in water; soluble in acetone; slightly soluble in chloroform, in ethanol (96%) and in ether.
Identification
A. The infrared absorption spectrum, Appendix II A, is concordant with the reference spectrum of dinitolmide (RSV 17).
B. Heat 1 g with 20 ml of 9M sulphuric acid under a reflux condenser for 1 hour, cool, add 50 ml of water
and filter. The melting point of the residue, after washing with water and drying at 105°, is about 205°, Appendix V A.
Acid value Not more than 5.0, Appendix X B, using 0.5 g and 50 ml of ethanol (96%) as the solvent.
Melting point 177° to 181°, Appendix V A.
Related substances Carry out the method for thin-layer chromatography, Appendix III A, using a silica gel F254 precoated plate (Merck plates are suitable) and a mixture of 5 volumes of glacial acetic acid, 10 volumes of methanol and 85 volumes of chloroform as the mobile phase. Apply separately to the plate 10 μl of each of three solutions in acetone containing (1) 2.5% w/v of the substance being examined, (2) 0.0125% w/v of the substance being examined and (3) 0.0125% w/v of o-toluic acid. After removal of the plate allow it to dry in air and examine under ultraviolet light (254 nm). Spray with titanium(iii) chloride solution diluted 1 to 5 with water, heat at 100° for 5 minutes and spray with alcoholic dimethylaminobenzaldehyde solution. When examined under ultraviolet light the spot in the chromatogram obtained with solution (3) is more intense than any corresponding spot in the chromatogram obtained with solution (1) (0.5%). By each method of visualisation any secondary spot in the chromatogram obtained with solution (1) is not more intense than the spot in the chromatogram obtained with solution (2) (0.5%).
Loss on drying When dried to constant weight at 105°, loses not more than 1.0% of its weight. Use 1 g.
Assay Dissolve 0.15 g in acetone and dilute to 50 ml. To 10 ml of this solution add 10 ml of glacial acetic acid and 15 ml of a 40% w/v solution of sodium acetate. Maintain a stream of carbon dioxide through the flask throughout the determination. Add 25 ml of 0.1M titanium(iii) chloride VS and allow to stand for 5 minutes. Add 10 ml of hydrochloric acid, 10 ml of water, and 1 ml of a 10% w/v solution of potassium thiocyanate. Titrate with 0.1M ammonium iron(iii) sulphate VS until the
solution becomes colourless and then orange. Repeat the operation without the substance being
examined. The difference between the titrations represents the amount of titanium(III) chloride required to reduce the dinitolmide. Each ml of 0.1M titanium(iii) chloride VS is equivalent to 1.876 mg of C8H7N3O5.
Action and use Coccidiostat.
球痢灵检测方法英文
