Determination of trace sulfur in light olefins by oxidation microcoulometric method (1)

1 Subject content and scope of application

This standard specifies the determination of the trace sulfur content in light olefins by the oxidation micro-co-enterprise method

This standard applies to the determination of trace sulfur in dry light olefins (C ₂～C ₄ )

2 Reference standards

GB 676 Chemical reagent glacial acid

GB 1272 Chemical Reagent Potassium Iodide

GB 6601 Pyrolysis C4 Liquid Sampling Method for Industrial Use

GB 7715 Industrial Ethylene

GB 7716 Industrial Propylene

3 Principles of the method

The sample is brought into the combustion tube by the carrier gas and mixed with oxygen and burned.

SO ₂ + the I ^- _.

Because the three iodine ions (I-3) in the electrolyte are consumed, the potential difference between the indicator electrode pairs changes, and then the corresponding current flows through the electrolysis electrode pairs, and the following reactions occur on the anode surface:

3I ^- → I3 ^- + 2E

When the triiodide ions (I produced by electrolysis ^- 3), the electrolyte triiodide ions (I _.

4 Reagents and solutions

Except for special regulations, the reagents used in this method are all analytical reagents

4.

4.

4.

4.

4.

4.

4.

Where: X—the sulfur content in the standard solution, ng/uL;

m — The mass of thiophene or butyl sulfide , g;

a—Purity of thiophene or butyl sulfide, %;

V—The volume to which n-octane or n-heptane is diluted, mL;

M —The molecular weight of thiophene or butyl sulfide ;

32.