SH/T 0177-1992 Determination of aromatic hydrocarbon content in light petroleum products (gravimetric method)

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Card type: Test method

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

• Method number: SH/T 0177-92
• Full name: Determination of aromatic hydrocarbon content in light petroleum products (gravimetric method)
• English name: not provided in the available source
• Replacement relationship: replaces ZB E31 006-88
• Other: approved in 1992-05-20, implemented in 1992-05-20; the source text marks “(20[unreadable year] confirmation)”, suspected to be “(20XX confirmation)”, requires confirmation against the source standard (source-text extraction)
• Additional notes: this standard was first published in 1958; it refers to and adopts the former Soviet national standard ГОСТ 6994-74 “Determination of aromatic hydrocarbon content in light petroleum products (gravimetric method)”

2. Scope of application and non-applicability

• Applicable to light petroleum products with relatively low olefin content [less than 10%(m/m)], such as aviation gasoline, straight-run gasoline and jet fuel.
• Not applicable: no explicit non-applicability clause is provided in the available source.

3. Method principle

Based on the principle that aromatic hydrocarbons and olefins in petroleum products undergo sulfonation with sulfuric acid at room temperature. The sample is treated with 98.5%～99.0%(m/m) sulfuric acid to extract the unsaturated hydrocarbons and aromatic hydrocarbons therein, and the aromatic hydrocarbon content is determined from the difference between the total hydrocarbons extracted by sulfuric acid and the unsaturated hydrocarbon content.

4. Reagents and materials (purity / preparation)

• 5.1 Sulfuric acid: chemically pure.
• 5.2 Fuming sulfuric acid: chemically pure.
• 5.3 Sodium hydroxide: chemically pure, prepared as c(NaOH)=0.5mol/L sodium hydroxide standard titration solution.
• 5.4 Phenolphthalein: prepared as 10g/L phenolphthalein-ethanol indicator solution.
• 6.1 Preparation of 98.5%～99.0%(m/m) sulfuric acid:
  • 6.1.1 Preparation: place the bottle containing 94%～?%(m/m) sulfuric acid in an ice bath to pre-cool, then add a fixed amount of fuming sulfuric acid to the bottle, shake well, and after standing for 3d, calibrate. (The source text “94%[unreadable separator]%%” is suspected to be something like “94%～96%”, requires confirmation against the source standard (source-text extraction))
  • 6.1.2 Calibration: use the decrement method to weigh 0.5g (accurate to ±0.0002g) of the prepared sulfuric acid solution into 50mL distilled water, mix uniformly, and after cooling add 2～3 drops of phenolphthalein-ethanol indicator solution, and titrate with sodium hydroxide standard titration solution (5.3) until a pale red color is the endpoint.
  • 6.1.3 Sulfuric acid content X₁[%(m/m)] is calculated according to formula (1): X₁ = (0.04904 × V × c) / m Where: 0.04904— is the mass of sulfuric acid in grams equivalent to 1.00mL sodium hydroxide standard titration solution [c(NaOH)=1.000mol/L]; c— is the actual concentration of the sodium hydroxide standard titration solution, mol/L; V— is the volume of sodium hydroxide standard titration solution consumed in the titration, mL; m— is the mass of the sulfuric acid solution, g.
  • 6.1.4 Permissible difference: the difference between two results of repeated determination shall not exceed 0.5% of the smaller result.

5. Instruments and equipment

• 4.1 Separatory funnel: 100mL.
• 4.2 Graduated cylinder: 10, 50mL.
• 4.3 Burette: 50mL.
• 4.4 Conical flask: 250mL.
• 4.5 Wash bottle: 500mL.
• 4.6 Balance: industrial balance with a sensitivity of 0.01g.
• 4.7 Analytical balance.
• 4.8 Stand: with a metal ring, for placing the separatory funnel.

6. Recommended operating conditions

• Sulfuric acid concentration: 98.5%～99.0%(m/m).
• Sulfuric acid amount: 30mL.
• Shaking time: 30min.
• Standing and layering time: 1h.
• Concentration of sodium hydroxide standard titration solution used for titration: 0.5mol/L.
• Indicator solution: phenolphthalein-ethanol indicator solution, add 3 drops (when calibrating sulfuric acid, add 2～3 drops).

7. Sampling and sample preparation

• 7.1 Tie the neck of a clean, dry separatory funnel with a thin metal wire, hang it on the hook of an industrial balance and weigh it, accurate to 0.01g, then measure 10mL of sample with a graduated cylinder and pour it into the separatory funnel, then weigh the separatory funnel containing the sample accurate to 0.01g, and calculate the mass of the sample.
• Other sampling and sample preparation requirements: not provided in the available source.

8. Analysis procedure

• 7.2 Inject 98.5%～99.0%(m/m) sulfuric acid 30mL into the separatory funnel containing the sample, shake for 30min; during shaking, place the separatory funnel on a shaker or shake it manually by hand, but during shaking continuously open the ground-glass stopper of the separatory funnel to release gas, so as to avoid forming relatively high pressure in the funnel and splashing the mixture of acid and oil out (especially in the first 5min of shaking after adding acid to aviation gasoline, gas must be released continuously). After shaking is completed, place the separatory funnel on the stand in a vertical position so that the mixture clarifies and the acid sludge and oil separate. After the separatory funnel has stood for 1h, open the stopcock of the separatory funnel, carefully release the lower acid sludge, then close the stopcock, twist filter paper into a paper stick, and wipe clean the residual acid sludge in the side tube (drain tube) of the funnel.
• 7.3 Weigh the funnel containing the sample again accurate to 0.01g, and calculate the mass of the sample after sulfuric acid treatment.
• 7.4 Place the separatory funnel back on the stand in a vertical position, put the sample into a conical flask, and carefully wash the ground-glass stopper of the separatory funnel and its inner wall three to four times with distilled water (about 20mL water each time), collecting the wash water in the conical flask containing the sample.
• 7.5 Add 3 drops of phenolphthalein-ethanol indicator solution to the conical flask containing the aqueous sample solution, and titrate with sodium hydroxide standard titration solution (5.3) until pale red.
• The mass m₁(g) of sulfuric acid [98.5%(m/m)] remaining in the sample and on the wall of the separatory funnel is calculated according to formula (2): m₁ = (V × 0.02452 × 100) / 98.5 Where: V— is the volume of sodium hydroxide standard titration solution consumed in the titration (converted to an accurate 0.5mol/L solution), mL; 0.02452— is the mass of pure sulfuric acid equivalent to 1mL of accurate 0.5mol/L sodium hydroxide standard titration solution, g; 98.5— is the concentration of the sulfuric acid used, %(m/m).

9. Qualitative and quantitative determination and calculation formulas

• The aromatic hydrocarbon content X₂[%(m/m)] in the sample is calculated according to formula (3): X₂ = [m₂ - (m₃ - m₁)] × 100 / m₂ - (I × M) / 254 Where: m₁—mass of sulfuric acid remaining in the sample and on the wall of the separatory funnel, g; m₂—mass of the sample before sulfuric acid treatment, g; m₃—mass of the sample after sulfuric acid treatment, g; I— is the iodine value of the sample measured according to SH/T 0234, or 100g; 254— molecular weight of iodine; M— average molecular weight of unsaturated hydrocarbons in the sample (found from the table below).
• Note: the original formula (3)source-text extraction contains noise, the formula form requires confirmation against the source standard (source-text extraction); “or 100g” is suspected to be something like “or 100”, requires confirmation against the source standard (source-text extraction).
• The average molecular weight M of unsaturated hydrocarbons in the sample is found from the table below (according to the 50% distillation temperature of the sample, GB/T 255):
  • The original table source-text extraction is severely disordered, and the numerical correspondence cannot be reliably restored, requires confirmation against the source standard (source-text extraction). The visible 50% distillation temperature values in the source include: 1, 4, 1, 6, 1, 1, 8, 0, 2, 0, 8, 1, 7, 5, 2, 5, 2, 5, 0, 7, 8, 7, 1, 2, 8, 5, 0, 7, 5, 1, 0, 1, 2, 5, 1, 5, 0, etc.; the specific correspondence is not reliably presented in the available source.

10. Precision

• Repeatability: the difference between two results of repeated determination by the same operator shall not exceed 1%(m/m).
• Reproducibility: not provided in the available source.

11. Report

Take the arithmetic mean of two results of repeated determination as the test result.

12. Referenced documents

• GB/T 255 Determination of distillation range of petroleum products
• SH/T 0234 Determination of iodine value and unsaturated hydrocarbon content of light petroleum products (iodine-ethanol method)

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