1.0) Description: Clear, colorless, volatile liquid.

2.0) Solubility: Sparingly soluble in water, miscible with ethanol (96per cent)

3.0) Identification

  1. Relative density . 
  1. B. Refractive index .
  1. C. Infrared absorption spectrophotometry.Preparation  Films.Comparison  methylene chloride CRS.
  1. Heat 2 mL with 2 g of potassium hydroxide Rand 20 mL of ethanol (96 per cent) R under a reflux condenser for 30 min. Allow to cool. Add 15 mL of dilute sulfuric acid R and filter. To 1 mL of the filtrate add 1 mL of a 15 g/L solution of chromotropic acid, sodium salt R, ·2 mL of water R and 8 mL of sulfuric acid R. A violet colour is produced.2 mL of the filtrate obtained in identification test D gives reaction (a) of chlorides .

4.0)       Tests

4.1)      Appearance

It is clear  and colourless .

 4.2)      Acidity

To 50 mL of methanol R previously neutralised to 0.1 mL of bromothymol blue solution Rl, add 50 g of the substance to be examined. Not more than 0.15 mL of 0.1 M sodium hydroxide is required to change the colour of the indicator to blue.

4.3)   Relative density : 1.320 to 1.332.

4.4)     Refractive index : 1.423 to 1.425.

4.5)  Ethanol, 2-methylbut-2-ene and volatile impurities

Gas chromatography .

Test solution The substance to be examined.

Reference solution (a) Dilute 100 µL of carbon tetrachloride R (impurity A), 500 µL of chloroform R (impurity B), 3.0 mL of 2-methylbut-2-ene Rand 5.0 mL of methanolR (impurity D) to 100.0 mL with the test solution.

Reference solution (b) Dilute 2.0 mL of anhydrous ethanol R and 1.0 mL of reference solution (a) to 100.0 mL with the test solution.


material: fused silica;

size: l = 30 m, Ø = 0.32 mm;

stationary phase: poly[(cyanopropyl) (phenyl)[dimethyl] siloxane R (film thickness 1.8 µm),

Carrier  gas  nitrogen  for  chromatography  R.

Flow rate 1.0 ml/min, constant flow.

Split ratio 1:40.



  Time (min.) Temperature (0C)
Column 0—5 40
5—12.5 40—55
12.5—18 55—100
18—20 100
Injection Port 260
Detector 300

Detection Flame ionisation; make-up gas flow rate: 25 ml/min.

Injection 2 µL of the test solution and reference solution (b).

Relative retention With reference to methylene chloride (retention time = about 7 min): impurity D == about 0.6; ethanol == about 0.8; 2-methylbut-2-ene == about 0.9; impurity B == about 1.7; impurity A = about 1.8.

System suitability Reference solution (b):

resolution: minimum 3.0 between the peaks due to ethanol and 2-methylbut-2-ene;

signal-to-noise ratio: minimum 5 for the peak due to impurity A.

Calculation of percentage contents:

– for ethanol, 2-methylbut-2-ene and impurities A and B, use the respective concentration of these substances in reference solution (b); correct the areas of the peaks in the chromatogram obtained with reference solution (b) by subtracting the area of the corresponding peak in the chromatogram obtained with the test solution;

– for any other impurity, use the concentration of impurity D in reference solution (b); correct the area of the peak due to impurity D in the chromatogram obtained with reference solution (b) by subtracting the area of the corresponding peak in the chromatogram obtained with the test solution.


– ethanol: maximum 2.0 per cent V/V;

2-methylbut-2-ene: maximum 300 ppm V/V;

impurity A: maximum 10 ppm VIV;

impurity B: maximum 50 ppm VIV;

– sum of impurities other than ethanoland 2-methylbut-2-ene: maximum 0.1 per cent V/V;

– reporting threshold: 50 ppm V/V; the reporting threshold does not apply to impurity A.

4.6)      Free chlorine

Place 5 mL in a ground-glass-stoppered tube. Add 5 mL of a 100 g/L solution of potassium iodide Rand 0.2 g of soluble starchR. Shake for 30 s and allow to stand for 5 min. No blue colour develops.

4.7)     Residue on evaporation

Maximum 20 ppm.

Evaporate 50.0 g to dryness on a water-bath and dry at 100-105 °C for 30 min. The residue weighs a maximum of 1 mg.

4.8)    Water

Maximum 0.02 per cent m/m, determined on 10.00 g