ASTM E256-09 Method for Chlorine in Organic Compounds by Sodium Peroxide Bomb Ignition

Scope:

ASTM E256-09 test method covers the determination of chlorine in organic compounds by sodium peroxide bomb ignition. The test method performs with an application of organic samples containing more than 0.5% chlorine. The procedure assumes that compounds containing halogens other than chlorine will not be present.

Test Procedure:

In ASTM E256-09 test method, the chlorine sample is heated in a closed bomb with sodium peroxide in the presence of an accelerator (potassium nitrate) and an oxygen-bearing compound (sucrose). The chlorine gets converted to chloride. The contents of the bomb are dissolved in water. The solution becomes acidified, and the chloride is determined by titrating the excess silver nitrate solution used to precipitate the chloride.

Figure 1: Titration Setup (Source: chem.libretexts.org)

Specimen size:

0.1g of Organic Compound

Data:

Calculate the chlorine content as follows:

Where:

X = V₁N₁ − V₂N₂,

Y = v₁N₁ − v₂N₂,

V1 = AgNO₃ solution used in the sample, mL,

V2 = NH₄SCN solution used in the sample, mL,

v1 = AgNO₃ solution used in the blank, mL,

v2 = NH₄SCN solution used in the blank, mL,

N1 = milliequivalents per millilitre of the AgNO₃ solution,

N2 = milliequivalents per millilitre of the NH₄SCN solution,

W = sample used, g, and

3.545 = (atomic wt of chlorine × 100)/1000.