GB/T 12688.4-2011Test method of styrene for industrial use -- Part 4: Determination of content of peroxides -- Titrimetric method (English PDF)

Foreword

GB/T 12688 "for industrial use - Test methods" is divided into the following sections.

--- Part 1. purity and hydrocarbon impurities - Gas chromatographic method;

--- Part 3. Determination of polymer content;

--- Part 4. Determination of the peroxide titration;

--- Part 5. Determination of total aldehyde titration;

--- Part 6. for industrial use - Determination of trace sulfur - Oxidative Microcoulometry;

--- Part 8. polymerization inhibitor (p - tert butyl catechol) determination of spectrophotometry;

--- Part 9. Trace Benzene by Gas Chromatography.

This section GB/T Part of 412,688.

The partial modification using ASTMD2340-09 "Standard Test Method for styrene monomer content of peroxides" (in English). Headquarters Structural differences and points of ASTMD2340-09 see Appendix A.

This section compared with ASTMD2340-09 main technical changes as follows.

--- Remove restrictions peroxide measurement range;

--- Normative references cited in our standards.

This Part replaces GB/T 12688.4-1990 "peroxide for industrial use - Determination of titration." this portion of the GB/T 12688.4-1990 The main differences are as follows.

--- Modify the standard name;

--- Added Appendix A.

Appendix A of this section is an informative annex.

This part is proposed by the China Petroleum and Chemical Corporation.

This part of the National Standardization Technical Committee Petrochemical Chemical Technical Committee (SAC/TC63/SC4) centralized.

This section drafted by. China Petroleum and Chemical Corporation Beijing Yanshan Company.

1 Scope

This section provides for industrial use Determination of styrene peroxide content.

This section is not intended to illustrate its use of all safety-related issues. Responsibility of the user to establish appropriate safety and health measures Facilities, to ensure compliance with the provisions of the relevant national regulations.

Note. styrene as flammable, exothermic polymerization reaction occurs when contact with peroxide, an inorganic acid and aluminum chloride and the like. High concentration its liquid styrene vapor on the eyes and respiratory system irritation there.

2 Normative references

The following documents contain provisions which, through reference GB/T 12688 in this section constitute provisions of this section. For dated reference documents Member, all subsequent amendments (not including errata content) or revisions do not apply to this section, however, encouraged to reach under this section Parties to research agreement to use the latest versions of these documents. For undated reference documents, the latest versions apply to this section.

GB/T 601 chemical reagent titration analysis (volumetric analysis) Preparation of standard solutions GB/T 3723 Sampling of chemical products for industrial use General Safety (GB/T 3723-1999, ISO 3165. 1976, idt) GB/T 6680 General rules for sampling liquid chemical products GB/T 6682 analytical laboratory use specifications and test methods (GB/T 6682-2008, ISO 3696. 1987, MOD) GB/T 8170 repair value expressed about the rules and limit values \u200b\u200band judgment

3 PRINCIPLE OF THE METHOD

Styrene and samples to an acetic acid solution of isopropanol, then isopropanol was added a saturated solution of sodium iodide and heated under reflux. Sample peroxide the reaction with sodium iodide compound quantitatively released iodine with sodium thiosulfate standard titration solution titrated to colorless as the end point, in accordance with standard sodium thiosulfate Consumption volume calculations quasi titration solution obtained peroxide content.

4 Reagents and materials

Unless otherwise indicated, the reagents used in this section should be of analytical grade. The water should meet the three water specifications GB/T 6682 regulations.

4.1 glacial acetic acid.

4.2 isopropanol.

NOTE. Isopropyl alcohol is flammable, away from open flame. In this test should be used fully sealed heater.

4.3 sodium thiosulfate standard titration solution [c (Na2S2O3) = 0.01mol/L]. formulated and calibrated according to the provisions of GB/T 601, so Diluted before use.

Isopropanol saturated solution of sodium iodide, 4.4. about 200g/L.

5 Apparatus

5.1 electric heater (fully enclosed).

5.2 iodine bottle stopper. 500mL, with 300mm spherical condenser, standard ground joint.