NB/SH/T 0399-2013 Determination of Peroxide Value of Petroleum Waxes

AI-translated method card — human verification pending. This is not an official translation of the standard. Unclear source values remain unverified; check the original standard and product certificate before use.

Card type: Test method

1. Method number / full title / English title / replacement relationship

• Standard number: NB/SH/T 0399—2013
• Chinese title: Determination of Peroxide Value of Petroleum Waxes
• English title: Standard test method for peroxide number of petroleum wax
• Replacement relationship: replaces SH/T 0399—2005 "Determination of Peroxide Value of Petroleum Waxes"
• Adoption relationship: adopts the redrafting method, modified adoption of ASTM D1832-04 "Determination of Peroxide Value of Petroleum Waxes" (English version)
• Issued / implemented: issued on 2013-06-08, implemented on 2013-10-01
• Issuing body: National Energy Administration
• First issued: 1992; first revision in 2005; this is the 2th revision
• Drafting organization: Fushun Research Institute of Petroleum and Petrochemicals, Sinopec Corp.
• Main drafters: Gao Bo, Liu Shuqin, Xu Zhiyang
• Secretariat: Subcommittee on Petroleum Waxes of the National Technical Committee for Standardization of Petroleum Products and Lubricants (SAC/TC280/SC3)
• Proposed by: China Petrochemical Corporation

2. Scope of application and non-applicability

• This standard specifies the method for determination of peroxide value of petroleum waxes.
• This standard applies to petroleum wax products.
• Not applicable: no explicit non-applicability clause is provided in the available source.

3. Method principle

A certain amount of sample is dissolved in xylene (the xylene must have oxidizing impurities removed; the removal method is to pass the xylene through an activated alumina column before use), and acidified with glacial acetic acid solution, potassium iodide solution is added, and after a certain reaction time, titration is performed with sodium thiosulfate solution, with the color change of starch indicator indicating the titration endpoint.

4. Reagents and materials (purity / preparation)

• 7.1 Reagent purity: the source text states "[reagent-grade wording garbled]; other reagent grades may be used if their purity is sufficient and their use does not reduce measurement precision" (unclear in the source text (source-text extraction)).
• 7.2 Water purity: distilled water, meeting the grade 3 water requirements in GB/T 6682, or water of equivalent purity.
• 7.3 Glacial acetic acid solution: mix 4 mL concentrated hydrochloric acid (HCl, relative density 1.19) with 996 mL glacial acetic acid (CH₃CO₂H) (source text "[garbled mixing instruction]" requires confirmation against the source standard (source-text extraction)).
  • Examination of reducing substances (alcohols and aldehydes) in glacial acetic acid: add 500 mL glacial acetic acid to a flask, place on a 40 ℃~50 ℃ water bath at constant temperature and heat, slowly add finely ground 5 g potassium dichromate into the flask, and shake continuously 30 min (source text "30g" requires confirmation against the source standard (source-text extraction)). If a redox reaction occurs, the temperature rises, indicating the presence of reducing substances; if the temperature change is within the range of 0.2 ℃, it indicates that it can be used.
• 7.4 Xylene: oxidizing impurities must be removed; the removal method is to pass the xylene through an activated alumina column before use; activation conditions for alumina: 150 ℃ (source text "1500C" requires confirmation against the source standard (source-text extraction)), activation time is 6 h.
• 7.5 Potassium dichromate standard solution (0.01667 mol/L): recrystallize twice potassium dichromate (K₂Cr₂O₇), dry at about 164 ℃ to constant weight, weigh 2.452 g of pure potassium dichromate, and dilute to 500 mL in a volumetric flask.
• 7.6 Potassium dichromate standard solution (0.001667 mol/L): in a volumetric flask, dilute 100 mL 0.01667 mol/L of potassium dichromate solution with water to 1 L (source text "to 1 [unit absent in this fragment]" requires confirmation against the source standard (source-text extraction)).
• 7.7 Potassium iodide solution: dissolve 120 g potassium iodide (KI) in 100 mL water. Remove any color of the solution as follows: place 1 mL potassium iodide solution, 50 mL water and 5 mL starch solution into a 300 mL flask, and cover with nitrogen or carbon dioxide gas. If a blue color appears, add 0.005 mol/L sodium thiosulfate solution with a microburette until the color just disappears. Based on the amount of sodium thiosulfate solution consumed to remove the color, calculate and add sufficient sodium thiosulfate solution to the potassium iodide mother liquor to convert free iodine to iodide. When starch solution is added to 1 mL potassium iodide solution, no blue color should appear. However, when 1 drops of 0.001667 mol/L potassium dichromate solution and 2 are added (source text interrupted here, requires confirmation against the source standard (source-text extraction)), a blue color should appear. Add a few milliliters of chloroform to the surface of the solution and store protected from light.
  • The amount of sodium thiosulfate added to the potassium iodide mother liquor V (mL) is calculated according to formula (1): V = ⅓ × V₀ (source formula shown as "V-⅓ xV", requires confirmation against the source standard (source-text extraction)) Where: V₀——the solution volume of 120 g potassium iodide (KI) dissolved in 100 mL water, mL; (the source text "[missing symbol] volume in mL of 0.005mol/L sodium thiosulfate solution consumed to remove the color" has a missing corresponding symbol, requires confirmation against the source standard (source-text extraction)) Y——1 unit potassium iodide solution volume, mL.
• 7.8 Sodium thiosulfate standard solution (0.1 mol/L): dissolve 12.5 g sodium thiosulfate (Na₂S₂O₃) and 0.1 g sodium carbonate (Na₂CO₃) in 500 mL water (source text "NexS. 0，" requires confirmation against the source standard (source-text extraction)). Store for at least 1 weeks before use, standardize with 0.01667 mol/L potassium dichromate solution, re-standardize after an interval, the concentration can only have a change of 0.000 (source text interrupted, requires confirmation against the source standard (source-text extraction)) mol/L.
• 7.9 Sodium thiosulfate standard solution (0.005 mol/L): in a volumetric flask, dilute 100 mL 0.1 mol/L sodium thiosulfate standard solution with water to 2000 mL, and standardize with 0.001667 mol/L potassium dichromate standard solution.
• 7.10 Starch solution: dissolve 1 g soluble starch in 400 mL boiling water, add a few milligrams of mercuric iodide (HgI₂) (source text "A0OmA" requires confirmation against the source standard (source-text extraction)).

5. Apparatus and equipment

• 6.1 Stoppered iodine flask: borosilicate glass, capacity 250 mL.
• 6.2 Constant-temperature water bath.
• 6.3 Electric thermostatic drying oven.
• 6.4 Balance: minimum division value 0.1 mg.
• 6.5 Microburette: capacity 10 mL (source text "10m〕" requires confirmation against the source standard (source-text extraction)).
• 6.6 Pipette: volume 2 mL (source text "2ml").
• 6.7 Thermometer: minimum division value 0.05 mL (source text "[garbled thermometer name]: minimum scale division 0.05 ml" requires confirmation against the source standard (source-text extraction), the unit is suspected to be ℃, requires confirmation against the source standard (source-text extraction)).

6. Recommended operating conditions

• Sample heating: heat the wax sample on a water bath or in an oven; the heating temperature must not exceed 65 ℃±5 ℃, or must not exceed the freezing point 11 ℃, because overheating may change the amount of peroxide (source text "65、5°C" "11°CC" requires confirmation against the source standard (source-text extraction)).
• Dissolving the sample: perform in a fume hood; the heating temperature must not exceed 55 ℃ (source text "555t" requires confirmation against the source standard (source-text extraction)).
• Reaction standing: add 2 mL potassium iodide solution and shake vigorously for 30 s; while carbon dioxide or high-purity nitrogen bubbles continue to pass through the mixture, let the iodine flask stand for 5 min.
• Titration: titrate with 0.005 mol/L sodium thiosulfate solution until pale yellow, add 6 mL starch solution, continue titration, add sodium thiosulfate solution dropwise until the blue color disappears and no color reappears for at least 30 s.

7. Sampling and sample preparation

• 8.1 Heat the wax sample on a water bath or in an oven; the heating temperature must not exceed 65 ℃±5 ℃, or must not exceed the freezing point 11 ℃, because overheating may change the amount of peroxide.
• 8.2 Weigh 1 g±0.2 g wax sample in a weighed iodine flask, accurate to 1 mg. Add 25 mL xylene (7.4) to the flask, place on a water bath, and rapidly dissolve the sample under carbon dioxide or high-purity nitrogen (note: perform in a fume hood; the heating temperature must not exceed 55 ℃), unless needed for dissolving the sample, otherwise (source text interrupted here, requires confirmation against the source standard (source-text extraction)).

8. Analytical procedure

• 8.2 At this point, the iodine flask is still in the water bath, and carbon dioxide or high-purity nitrogen gas is visibly bubbling through the solution 1 min, then reduce the flow rate of carbon dioxide or high-purity nitrogen to 1 bubbles per second, add 20 mL glacial acetic acid solution; the glacial acetic acid solution should be sufficiently warmed to prevent wax precipitation. Remove the iodine flask from the water bath, continue passing carbon dioxide or high-purity nitrogen, add 2 mL potassium iodide solution and shake vigorously 30 s; while carbon dioxide or high-purity nitrogen bubbles continue to pass through the mixture, let the iodine flask stand 5 min. Stop the gas flow, add 100 mL (the source text is interrupted here, requires confirmation against the source standard (source-text extraction)), mix 1 min. Titrate with 0.005 mol/L sodium thiosulfate solution until pale yellow, add 6 mL starch solution, continue titration, add sodium thiosulfate solution dropwise until the blue color disappears and no color reappears for at least 30 s.
• 8.3 Perform a blank determination, following the procedure described in 8.2 except that no test sample is added.

9. Qualitative and Quantitative Determination and Calculation Formula

• The peroxide value is expressed as millimoles per 1000 g of test sample. Calculate according to formula (2): Peroxide value = [(A - B) × N × 1000] / W (the original formula is displayed as "[(4-B)N×1000J48", requires confirmation against the source standard (source-text extraction)) Where: A—— volume of sodium thiosulfate solution consumed in titrating the test sample, mL; B—— volume of sodium thiosulfate solution consumed in the blank titration, mL; N—— concentration of sodium thiosulfate solution, mol/L; W—— mass of test sample, g.
• Take the arithmetic mean of two results as the determination result, with the value accurate to two decimal places.

10. Precision

• 11.1 Precision: Judge the reliability of the results according to the following provisions (95% confidence level).
• 11.1.1 Repeatability (r): For determinations on the same test sample by the same operator using the same equipment under the same operating conditions, under correct operation, the experimental results shall not exceed the following values:
  • Peroxide value range: the numerical values in the original table are missing (requires confirmation against the source standard (source-text extraction))
  • Repeatability: 1.5
• 11.1.2 Reproducibility (R): For determinations on the same test sample by different operators in different laboratories, under correct operation, the experimental results shall not exceed the following values:
  • Peroxide value range: 0~15
  • Reproducibility: 3.3
• Note 1: For tests with peroxide value greater than 15, the precision range has not yet been determined.
• Note 2: Although xylene is used instead of carbon tetrachloride in this standard, the precision ranges of 11.1.1 and 11.1.2 are still determined using carbon tetrachloride as solvent rather than xylene.
• 11.2 Bias: Since the peroxide value is defined only by this method, there is no bias in this test procedure.

11. Report

not provided in the available source.

12. Normative References

• GB/T 601 Chemical reagents — Preparation of standard titration solutions
• GB/T 6682 Specifications and test methods for analytical laboratory water (GB/T 6682—2008, ISO 3696:1987, MOD) (the original text "CB/T 6682" requires confirmation against the source standard (source-text extraction))
• ASTM D1832-04 Determination of peroxide value of petroleum wax (English version) (modified adoption)

13. Source and verification

This page is an AI translation of the available Chinese method card. Human verification is pending. It is not an official translation of the standard. Check the source standard and product certificate before use.

14. Quick Reference Q&A