GB/T 11079-2015 White oil carbonizable substances test method

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Card type: Test method

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

• Standard number: GB/T 11079—2015
• Chinese full title: White oil carbonizable substances test method
• English name: Test method for carbonizable substances in white mineral oil
• Replacement relationship: replaces GB/T 11079—2000 "White oil carbonizable substances test method"
• Adoption relationship: modified adoption using the redrafting method of ASTM D565-99(2013) "White mineral oil carbonizable substances test method" (English version)
• Publication / implementation: published on 2015-12-31, implemented on 2016-06-01
• Custodianship: National Technical Committee for Standardization of Petroleum Products and Lubricants (SAC/TC280)
• Drafting organization: Fushun Research Institute of Petroleum and Petrochemicals, China Petroleum & Chemical Corporation
• Main drafters: Zhao Bin, Geng Chenchen
• First publication: 1987 year 5 month; first revision in 2000 year 6 month; this is the second revision

2. Scope of application and non-applicability

• This standard specifies the test method for carbonizable substances in white oil.
• This standard applies to white oil.
• Non-applicability: not provided in the available source.

3. Method principle

Under specified conditions, treat white oil with concentrated sulfuric acid, and compare the treated color with a standard colorimetric solution to determine whether it passes the test. (Chapter 3 Method summary)

4. Reagents and materials (purity / preparation)

• 6.1 Distilled water: meets the grade three water specification requirements of GB/T 6682.
• 6.2 Sulfuric acid: guaranteed reagent, content 95%~98% (mass fraction) (Warning: can cause severe burns, vapor is extremely irritating, strong oxidizer), should be nitrogen-free, prepare a sulfuric acid solution with a mass fraction of 94.7%±0.2% (standardized by acid-base neutralization titration); also prepare a sulfuric acid solution according to the volume ratio of sulfuric acid to distilled water of 1:3 (slowly add acid to water, use after cooling). Nitrogen-free test: dilute the sulfuric acid to be tested with an equal volume of distilled water, cool; take 10 mL of the cooled sulfuric acid solution, gently layer it on 10 g/L diphenylamine sulfuric acid solution, do not mix, within 1 h no blue color should appear at the contact interface; this method can detect nitric acid (HNO₃) at levels as low as 0.0002% (mass fraction).
• 6.3 Concentrated hydrochloric acid: analytical reagent, content 36% (mass fraction)~38% (mass fraction) (Warning: can cause burns, vapor is extremely irritating). Prepare a dilute hydrochloric acid solution according to the volume ratio of hydrochloric acid to distilled water of 1:39 (slowly add acid to water).
• 6.4 Glacial acetic acid: analytical reagent, content 99% (mass fraction) or above (Warning: corrosive, vapor is irritating). Mix 353 mL concentrated acetic acid and 1000 mL water (slowly add acid to water) to prepare a 6.0 mol/L glacial acetic acid aqueous solution.
• 6.5 Hydrogen peroxide: analytical reagent, prepare a 3% (volume fraction) hydrogen peroxide aqueous solution.
• 6.6 Copper sulfate (CuSO₄·5H₂O): analytical reagent.
• 6.7 Cobalt chloride (CoCl₂·6H₂O): analytical reagent.
• 6.8 Ferric chloride (FeCl₃·6H₂O): analytical reagent.
• 6.9 Sodium hydroxide: analytical reagent (Warning: corrosive, can cause severe burns or blindness, reacts violently with water releasing a large amount of heat or causing liquid splashing), mix 5 g sodium hydroxide and 20 mL distilled water to prepare a sodium hydroxide solution (1:4).
• 6.10 Potassium iodide: analytical reagent.
• 6.11 Diphenylamine: analytical reagent. Dissolve 1 g diphenylamine in 100 mL concentrated sulfuric acid with a mass fraction of 95%~98% to prepare a 10 g/L sulfuric acid solution.
• 6.12 Soluble starch: analytical reagent, prepare a 10 g/L aqueous solution as indicator.
• 6.13 Methyl orange indicator: analytical reagent, prepare a 5 g/L aqueous solution.
• 6.14 Sodium thiosulfate: analytical reagent, prepare and standardize a 0.1 mol/L sodium thiosulfate standard solution according to GB/T 601.
• 6.15 Cleaning solution: chromic acid (H₂CrO₄) cleaning solution (Warning: can cause severe burns, recognized carcinogen, strong oxidizer) or non-chromium strong oxidizing cleaning solution.
• 6.16 Reference white oil: No. 10 or No. 15, white oil meeting the requirements of GB 4853 or equivalent.

5. Apparatus and equipment

• 5.1 Test tube: as shown in Figure 1, a heat-resistant glass test tube with a ground glass stopper, the glass stopper and test tube have the same and not easily damaged number, the glass stopper uses a No. 13 standard ground joint, test tube length 140 mm±2 mm, average wall thickness 1.2 mm, outer diameter 14.5 mm–15.0 mm, after calibration of the 5 mL and 10 mL graduation lines, the error should not exceed ±0.2 mL. After covering with the glass stopper, the test tube volume is 13.6 mL–15.6 mL, the test tube mouth is flared outward to clamp the test tube on the water bath cover.
• 5.2 Water bath: capable of immersing the test tube above the 10 mL graduation line, can maintain constant temperature up to 100 ℃±0.5 ℃. The water bath has a bath cover made of suitable material, with holes of diameter about 16 mm, through which the test tube can be suspended.
• 5.3 Colorimeter: used to observe and compare the color of the sample acid layer with the color of the standard colorimetric solution, the size and shape of the colorimeter can be arbitrary, but the size and shape of the opening should conform to the dimensions shown in Figure 2.
• 5.4 Constant temperature oven: capable of heating to 105 ℃ and maintaining constant temperature, precision 1 ℃.
• 5.5 Thermometer: 0 ℃~105 ℃, minimum division 0.5 ℃.
• 5.6 Graduated pipette: 1 mL, 5 mL, 10 mL, 20 mL, 25 mL.
• 5.7 Volumetric flask: 1000 mL.
• 5.8 Iodine flask: 250 mL.
• 5.9 Burette: 50 mL.

6. Recommended operating conditions

• Water bath temperature: 100 ℃±0.5 ℃ (5.2, 8.2).
• Constant temperature oven temperature: 105 ℃±1 ℃ (5.4, 8.1).
• Sulfuric acid solution mass fraction: 94.7%±0.2% (6.2, 8.2).
• Water bath heating time: from the first placement of the test tube in the water bath until removal of the test tube after 10 min (8.4).
• Shaking conditions: amplitude about 127 mm, shaking rate 5 times per second, repeat the operation once every 30 s, the test tube must not leave the water bath for more than 3 s during each shaking cycle (8.3).
• Standing time: stand indoors for 10 min~30 min (8.4).

7. Sampling and sample preparation

• 8.2 Into a clean and dried test tube, inject sulfuric acid solution with a mass fraction of 94.7%±0.2% to the 5 mL graduation line, then add sample to the 10 mL graduation line, gently stopper the test tube, place the test tube in a water bath at 100 ℃±0.5 ℃.
• Other sampling and sample preparation requirements: not provided in the available source.

8. Analysis procedure

• 8.1 Clean the test tube with chromic acid (H₂CrO₄) cleaning solution or non-chromium strong oxidizing cleaning solution, then rinse with tap water, then wash with distilled water, and dry in a constant temperature oven at 105 ℃±1 ℃ for 30 min.
• 8.2 Into a clean and dried test tube, inject sulfuric acid solution with a mass fraction of 94.7%±0.2% to the 5 mL graduation line, then add sample to the 10 mL graduation line, gently stopper the test tube, place the test tube in a water bath at 100 ℃±0.5 ℃.
• 8.3 After heating the test tube in the water bath for 30 s, loosen the test tube stopper to release the pressure inside the test tube, then stopper the test tube again, quickly remove the test tube from the water bath, hold the test tube stopper with fingers, and shake vigorously three times in the vertical direction (Warning: sulfuric acid may spray out during shaking), with an amplitude of about 127 mm, shaking rate 5 times per second (a shaking machine that gives results consistent with the specified manual shaking may be used), repeat the operation once every 30 s, the test tube must not leave the water bath for more than 3 s during each shaking cycle.
• 8.4 From the first placement of the test tube in the water bath until removal of the test tube after 10 min, stand indoors for 10 min~30 min, observe whether the oil layer changes color and record. Place the test tube in the colorimeter, compare the color of the acid layer with the color of the standard colorimetric solution after shaking and layering.

9. Qualitative and quantitative determination and calculation formula

• 9.1 When the color of the oil layer does not change and the color of the acid layer is not darker than the standard colorimetric solution, report the sample as "passing" the test. Note: If there is a light blue haze, light pink, or yellow in the oil layer, it is not considered a color change.
• 9.2 If the oil layer changes color or the acid layer is darker than the standard colorimetric solution, report the sample as "failing" the test.
• 9.3 If the results of two replicate tests differ, a third test should be conducted, and the two identical test results shall be taken as the test result of the sample.
• Calculation formula: not provided in the available source (this method is a pass/fail determination, no calculation formula).

Preparation of standard colorimetric solution (Chapter 7)

• 7.1 Preparation of cobalt chloride solution (0.25 mol/L): Weigh cobalt chloride (CoCl₂·6H₂O) 65 g±1 g, place in a 1000 mL volumetric flask, and dilute to the mark with hydrochloric acid solution (1:39). After the cobalt chloride has completely dissolved, use a pipette to accurately measure 5 mL into a 250 mL iodine flask, add 15 mL sodium hydroxide solution (1:4) and 5 mL 3% (volume fraction) hydrogen peroxide aqueous solution, boil for 10 min±1 min, after cooling, add 2 g potassium iodide and 20 mL sulfuric acid solution (1:3), shake well, let stand, and after the precipitate has completely dissolved, titrate the free iodine with 0.1 mol/L sodium thiosulfate standard solution; near the end point, add 2 mL starch solution, and continue titrating until the blue color of the solution disappears. Each milliliter of 0.1 mol/L sodium thiosulfate standard solution is equivalent to 0.0238 g cobalt chloride (CoCl₂·6H₂O). Add hydrochloric acid solution (1:39) to adjust the final volume of the cobalt chloride solution so that each milliliter of solution contains 59.5 mg cobalt chloride (CoCl₂·6H₂O).
• 7.2 Preparation of copper sulfate solution (0.25 mol/L): Weigh copper sulfate (CuSO₄·5H₂O) 65 g±1 g, place in a 1000 mL volumetric flask, and dilute to the mark with hydrochloric acid solution (1:39). After the copper sulfate has completely dissolved, use a pipette to accurately measure 10 mL into a 250 mL iodine flask, add 40 mL distilled water, 4 mL 6 mol/L glacial acetic acid solution, 3 g potassium iodide and 5 mL hydrochloric acid, shake well, and titrate the free iodine with 0.1 mol/L sodium thiosulfate standard solution; near the end point, add 2 mL starch solution, and continue titrating until the blue color of the solution disappears. Each milliliter of 0.1 mol/L sodium thiosulfate standard solution is equivalent to 0.0250 g copper sulfate (CuSO₄·5H₂O). Add hydrochloric acid solution (1:39) to adjust the final volume of the copper sulfate solution so that each milliliter of solution contains 62.4 mg copper sulfate (CuSO₄·5H₂O).
• 7.3 Preparation of ferric chloride solution (0.166 mol/L): Weigh ferric chloride (FeCl₃·6H₂O) 55 g±1 g, place in a 1000 mL volumetric flask, and dilute to the mark with hydrochloric acid solution (1:39). After the ferric chloride has completely dissolved, use a pipette to accurately measure 10 mL into a 250 mL iodine flask, add 15 mL distilled water, 3 g potassium iodide and 5 mL hydrochloric acid, let stand for 15 min±1 min, then dilute the mixture with 100 mL distilled water, shake well, and titrate the free iodine with 0.1 mol/L sodium thiosulfate standard solution; near the end point, add 2 mL starch solution, and continue titrating until the blue color of the solution disappears. Each milliliter of 0.1 mol/L sodium thiosulfate standard solution is equivalent to 0.0270 g ferric chloride (FeCl₃·6H₂O). Add hydrochloric acid solution (1:39) to adjust the final volume of the ferric chloride solution so that each milliliter of solution contains 45.0 mg ferric chloride (FeCl₃·6H₂O).
• Note: As long as the proportions of the solution components are the same, the amounts of solution prepared according to 7.1~7.3 may be different.
• 7.4 Preparation of standard colorimetric solution: Take 1.5 parts cobalt chloride solution (7.1), 3.0 parts ferric chloride solution (7.3) and 0.5 parts copper sulfate solution (7.2), and prepare a light amber standard colorimetric solution. Take 5 mL standard colorimetric solution in a test tube (5.1), and cover the standard colorimetric solution with 5 mL reference white oil sample. Before the test, subject the standard colorimetric solution to vigorous shaking for 10 s and then allow sufficient standing for layer separation.

10. Precision

Because the result only indicates whether it is consistent with the standard specified in the procedure, this test method does not specify precision and bias. (Chapter 10)

11. Report

• 9.1 When the color of the oil layer remains unchanged and the color of the acid layer is not darker than the standard colorimetric solution, report the sample as "passing" the test.
• 9.2 If the oil layer changes color or the acid layer is darker than the standard colorimetric solution, report the sample as "failing" the test.
• 9.3 If the results of two replicate tests differ, a third test shall be conducted, and the two identical test results shall be taken as the test result of the sample.
• Other report format requirements: not provided in the available source.

12. Referenced Documents

• GB/T 601 Chemical reagents — Preparation of standard titration solutions
• GB 4853 Food-grade white oil
• GB/T 6682 Water for analytical laboratory use — Specification and test methods

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