SH/T 0236-1992 Determination of Bromine Value of Petroleum Products

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: SH/T 0236-92 (confirmed in 2004)
• Chinese title: Determination of Bromine Value of Petroleum Products
• English title: not provided in the available source
• Replacement relationship: replaces SY 2123-77(88)
• Approval/implementation: approved by China Petrochemical Corporation 1992-05-20, implemented on 1992-05-20

2. Scope of application and non-applicability

• This standard specifies the method for determining the bromine value of a sample.
• This standard applies to petroleum products.
• Not applicable: not provided in the available source.

3. Method principle

Dissolve the sample in the titration solvent, use methyl orange as indicator, and titrate with potassium bromate-potassium bromide standard titration solution until the red color disappears. The bromine value is expressed as the number of grams of bromine consumed by 100 g of sample.

4. Reagents and materials (purity / preparation)

• 4.1 Potassium bromate: analytical reagent.
• 4.2 Potassium bromide: analytical reagent.
• 4.3 Sodium thiosulfate: analytical reagent, prepared as c(Na2S2O3) into 0.1 and 0.5 mol/L standard titration solution.
• 4.4 Glacial acetic acid: analytical reagent.
• 4.5 Sulfuric acid: analytical reagent, prepared as 26%(m/m) solution.
• 4.6 Hydrochloric acid: analytical reagent, prepared as 19%(m/m) solution.
• 4.7 Methanol: analytical reagent.
• 4.8 95% ethanol: analytical reagent.
• 4.9 Carbon tetrachloride: analytical reagent.
• 4.10 Mercuric chloride: analytical reagent, prepared as 100 g/L ethanol solution.
• 4.11 Methyl orange indicator: prepared as 1 g/L indicator solution.
• 4.12 Starch: freshly prepared 5 g/L indicator solution.

Preparation of titration solvent (5.1): mix glacial acetic acid, sulfuric acid solution [26%(m/m)], methanol, carbon tetrachloride, and mercuric chloride ethanol solution (100 g/L) uniformly in a volume ratio of 73:3:7:15:2.

Preparation and standardization of potassium bromate-potassium bromide standard titration solution:

• 5.2.1 c(1/6KBrO3)=0.1 mol/L:
  • Preparation: weigh 3 g solid potassium bromate and 25 g potassium bromide, place in a 1 L volumetric flask, dilute to the mark with distilled water that has been boiled and then cooled, shake thoroughly, after complete dissolution filter into a brown bottle, and shake well.
  • Standardization: take 10 mL solution in an iodine flask, add 2 g potassium iodide and 5 mL hydrochloric acid solution [19%(m/m)], shake well, stopper, seal with water, add 25 mL water to dilute. Titrate with c(Na2S2O3)=0.1 mol/L sodium thiosulfate standard titration solution until pale yellow, add 1 mL starch indicator solution (5 g/L), continue titrating until colorless. Perform a blank test at the same time.
• 5.2.2 c(1/6KBrO3)=0.5 mol/L:
  • Preparation: weigh 15 g solid potassium bromate and 50 g potassium bromide, place in a 1 L volumetric flask, dilute to the mark with distilled water that has been boiled and then cooled, shake thoroughly, after complete dissolution filter into a brown bottle, and shake well.
  • Standardization: take 5 mL solution in an iodine flask, add 2 g potassium iodide and 5 mL hydrochloric acid solution [19%(m/m)], shake well, stopper, seal with water, add 25 mL water to dilute. Titrate with c(Na2S2O3)=0.5 mol/L sodium thiosulfate standard titration solution until pale yellow, add 1 mL starch indicator solution (5 g/L), continue titrating until colorless. Perform a blank test at the same time.

5. Instruments and equipment

• 3.1 Conical flask: 50, 100, 150 mL.
• 3.2 Pipette: 2, 5, 10 mL.
• 3.3 Microburette: 2, 5 mL, with graduations of 0.02 mL.
• 3.4 Graduated cylinder: 50 mL.
• 3.5 Iodine flask: 250 mL.
• 3.6 Volumetric flask: 1 L.

6. Recommended operating conditions

• Indicator: methyl orange indicator solution (1 g/L), add 1 drops.
• The amount of titration solvent added is specified according to the bromine value range of the sample (original table, source-text extraction doubtful point requires confirmation against the source standard):

Note (source-text extraction doubtful point): in the original table, the numerical column shows “10—15 / 16—35 / 36—55 / 56—85 / 86—100”, etc., and the correspondence with the bromine value intervals requires confirmation against the source standard (source-text extraction).

• Selection of standard titration solution:
  • Bromine value ≥ 0.5 gBr/100g: use c(1/6KBrO3)=0.5 mol/L.
  • Bromine value < 0.5 gBr/100g: use c(1/6KBrO3)=0.1 mol/L.

7. Sampling and sample preparation

• 6.1: use a 50 mL graduated cylinder to take the titration solvent (its amount is measured according to the table specification based on the bromine value) and pour it into a 50 mL (or 100, 150 mL) conical flask, add 1 drops of methyl orange indicator solution (1 g/L), and titrate with potassium bromate-potassium bromide standard titration solution (5.2.1 or 5.2.2) until the red color disappears.
• 7.2: according to the bromine value of the sample, use a pipette to measure 0.5—5 mL of sample, inject it into the conical flask of clause 6.1, then add 1 drops of methyl orange indicator solution (1 g/L), and shake thoroughly to mix evenly.
• Other content of sample preparation: not provided in the available source.

8. Analytical procedure

• Treat the titration solvent according to 6.1 and pre-titrate until the red color disappears.
• Add the sample according to 7.2 and shake thoroughly to mix evenly.
• Titrate with potassium bromate-potassium bromide standard titration solution (5.2.1 or 5.2.2) (titration should be slower, and attention should be paid to continuous shaking), until the red color of the mixed liquid disappears.

9. Qualitative and quantitative determination and calculation formulas

• The actual concentration of potassium bromate-potassium bromide standard titration solution c(1/6KBrO3), mol/L, is calculated according to formula (1):

c(1/6KBrO3) = c(Na2S2O3) × (V1 − V0) / V

Where:

• c(Na2S2O3): the actual concentration of sodium thiosulfate standard titration solution, mol/L;

• V: the volume of potassium bromate-potassium bromide solution, mL;

• V0: the volume of sodium thiosulfate standard titration solution consumed in the blank test, mL;

• V1: the volume of sodium thiosulfate standard titration solution consumed during titration, mL.

• The bromine value of the sample X(gBr/100g) is calculated according to formula (2):

X = (V2 × c(1/6KBrO3) × 0.0799) / (V3 × ρ)

Where:

• V2: the volume of potassium bromate-potassium bromide standard titration solution consumed during titration, mL;
• c(1/6KBrO3): the actual concentration of potassium bromate-potassium bromide standard titration solution, mol/L;
• V3: the volume of sample added, mL;
• ρ: the density of the sample at the sampling temperature, g/mL;
• 0.0799: the mass of bromine in grams equivalent to 1.00 mL potassium bromate-potassium bromide standard titration solution [c(1/6KBrO3)=1.000 mol/L].

(source-text extraction doubtful point: in formula (2), the transcription of the symbol interpreted as V2 is unclear; verify it against the original standard.)

10. Precision

Repeatability: the difference between two results of repeated determinations by the same operator shall not exceed the following values:

11. Report

Take the arithmetic mean of the two results of repeated determinations as the bromine value of the sample.

12. Referenced documents

not provided in the available source.

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 Q&A reference