Edition: BP 2025 (Ph. Eur. 11.6 update)
DEFINITION
Undec-10-enoic acid.
Content
97.0 per cent to 102.0 per cent.
CHARACTERS
Appearance
White or very pale yellow, crystalline mass or colourless or pale yellow liquid.
Solubility
Practically insoluble in water, freely soluble in ethanol (96 per cent) and in fatty and essential oils.
IDENTIFICATION
A. Refractive index (2.2.6): 1.447 to 1.450, determined at 25 ± 0.5 °C.
B. Freezing point (2.2.18): 21 °C to 24 °C.
C. To 2.0 g add 2 mL of freshly distilled aniline R and boil under a reflux condenser for 10 min. Allow to cool and add 30 mL of ether R. Shake with 3 quantities, each of 20 mL, of dilute hydrochloric acid R and then with 20 mL of water R. Evaporate the organic layer to dryness on a water-bath. After recrystallising twice from ethanol (70 per cent V/V) R and drying in vacuo for 3 h, the residue melts (2.2.14) at 66 °C to 68 °C.
D. Dissolve 0.1 g in a mixture of 2 mL of dilute sulfuric acid R and 5 mL of glacial acetic acid R. Add dropwise 0.25 mL of potassium permanganate solution R. The colour of the potassium permanganate is discharged.
TESTS
Peroxide value (2.5.5, Method A)
Maximum 10.
Fixed and mineral oils
To 1.0 g add 5 mL of sodium carbonate solution R and 25 mL of water R and boil for 3 min. The hot solution is not more opalescent than reference suspension II (2.2.1).
Water-soluble acids
To 1.0 g add 20 mL of water R heated to 35-45 °C and shake for 2 min. Cool and filter the aqueous layer through a moistened filter. To 10 mL of the filtrate add 0.1 mL of phenolphthalein solution R. Not more than 0.1 mL of 0.1 M sodium hydroxide is required to change the colour of the indicator.
Degree of unsaturation
Dissolve 85.0 mg in a mixture of 5 mL of dilute hydrochloric acid R and 30 mL of glacial acetic acid R. Using 0.05 mL of indigo carmine solution R1 as indicator, added towards the end of the titration, titrate with 0.0167 M bromide-bromate until the colour changes from blue to yellow. 8.9 mL to 9.4 mL of 0.0167 M bromide-bromate is required. Carry out a blank titration.
Sulfated ash (2.4.14)
Maximum 0.1 per cent, determined on 0.50 g.
ASSAY
Dissolve 0.750 g in 10 mL of ethanol (96 per cent) R. Titrate with 0.5 M sodium hydroxide using 0.1 mL of phenolphthalein solution R as indicator, until a pink colour is obtained.
1 mL of 0.5 M sodium hydroxide is equivalent to 92.14 mg of C11H20O2.
STORAGE
In a non-metallic container, protected from light.
