How to qualitatively and quantitatively analyze unknown impurities in VCM
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In the analysis of VCM, known impurities such as acetylene, ethane, dichloromethane, dichloroethylene, etc., can be analyzed; however, there are also some unknown impurities that our technical staff need to further investigate. How to analyze?
Reply to 1# wang*neng: Using gas chromatography, 14 types of impurities present in VCM monomer were analyzed, including methane, ethane, propane, propylene, acetylene, isobutane, methylene, butane, isobutylene, methylacetylene, chloromethane, 1,3-butadiene, ethylacetylene, and ethyl chloride. Chromatographic conditions: Column stationary phase – a mixture of 17.5% tributyl phosphate, 6.0% bis-2-ethoxyethyl adipate, and 1.5% dibutyl sebacate; stationary phase type: Chro2mosorb P-NAW, with a particle size of 60/80 mesh; column length: 3 m, inner diameter: 6.35 mm, made of stainless steel. Carrier gas: High-purity N2 at 30 mL/min. Hydrogen: Pure H2 at 40 mL/min. Air: Purified instrument air at 400 mL/min. Column temperature: 35. Injector temperature: 150. Detector temperature: 200 (conditions used by others previously). Standard gases containing multiple components (those listed above or more) are prepared, so as to determine the quantity and concentration of impurities in the sample. VCM monomer also contains impurities such as NaCl, acids, acetaldehyde, hydroquinone, non-volatile substances, water, and iron; the detection of these impurities can be carried out using various methods such as ultraviolet spectrophotometry (for hydroquinone and iron), Karl Fischer titration for water determination, and chemical titration