SH/T 0561-1993 Determination of thermal decomposition temperature of antioxidant and anti-corrosion additives (capillary method)

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 name / English name / replacement relationship

• Method number: SH/T 0561-93
• Full name: Determination of thermal decomposition temperature of antioxidant and anti-corrosion additives (capillary method)
• English name: not provided in the available source
• Replacement relationship: not provided in the available source (the source text marks "(confirmed in 2004)")
• Approval/implementation: approved by China Petrochemical Corporation in 1993-06-11, implemented in 1994-05-01

2. Scope of application and non-applicability

• Scope of application: This standard applies to antioxidant and anti-corrosion additives.
• Non-applicability: not provided in the available source.

3. Method principle

Inject the sample into a capillary tube of a specified size, heat it under specified conditions, and measure the lowest temperature at which the sample changes into a white crystalline substance; this is the thermal decomposition temperature of the sample.

4. Reagents and materials (purity / preparation)

• Methyl silicone oil: industrial grade.
• Preparation: not provided in the available source.

5. Apparatus and equipment

• 4.1.1 Beaker: 500 mL.
• 4.1.2 Thermometer: an open-cup flash point thermometer of number 1 as specified in GB/T 514.
• 4.1.3 Glass test tube: round bottom, height 160 mm±10 mm, inner diameter 20 mm±1 mm.
• 4.1.4 Ring-shaped glass rod or metal wire stirrer.
• 4.1.5 Syringe: 2 mL, graduation value 0.1 mL.
• 4.1.6 Closed needle of number 6.
• 4.1.7 Capillary tube: length 80 mm±1 mm, inner diameter 1.5 mm±0.1 mm, one end sealed, wall thickness about 0.15 mm. Material is hard glass.
• 4.1.8 Electric furnace: adjustable temperature.
• 4.1.9 Asbestos gauze.

6. Recommended operating conditions

• Heating method: heat the beaker on an electric furnace with an asbestos gauze placed on top.
• Heating rate control: when the temperature reaches 40℃ before the expected thermal decomposition temperature, adjust the heating rate so that at 20℃ before the expected thermal decomposition temperature, the heating rate is controlled at an increase of 2～3℃ per minute.
• Stirring: stir continuously during heating.
• Temperature reading: read to 0.5℃.
• Other conditions: not provided in the available source.

7. Sampling and sample preparation

• 5.1 Fill a 500 mL beaker with methyl silicone oil to two-thirds of its volume.
• 5.2 Fill a glass test tube with methyl silicone oil to a height of about 50 mm.
• 6.1 Shake the sample thoroughly until uniform, and use a syringe to inject the sample into the capillary tube to a liquid layer height of 5～6 mm; during injection, the needle should be inserted to the bottom of the capillary tube so that no bubbles remain in the injected sample.

8. Analytical procedure

• 6.2 Attach the capillary tube containing the sample to a thermometer with a rubber sleeve on a cork stopper, and keep the center of the sample liquid column at the same height as the middle of the thermometer mercury bulb.
• 6.3 Fix the capillary tube and thermometer with a cork stopper at the center of the glass test tube, and keep the bottom of the thermometer mercury bulb at a distance of 8～10 mm from the bottom of the glass test tube.
• 6.4 Place the glass test tube vertically at the center of the beaker containing methyl silicone oil, so that the bottom of the glass test tube is at a distance of 15～20 mm from the bottom of the beaker, and the methyl silicone oil level in the beaker is at least 10 mm higher than the methyl silicone oil level in the glass test tube; place the stirrer into the beaker.
• 6.5 Place an asbestos gauze on the electric furnace and heat the beaker, adjusting the temperature so that it rises uniformly. When the temperature reaches 40℃ before the expected thermal decomposition temperature, adjust the heating rate so that at 20℃ before the expected thermal decomposition temperature, the heating rate is controlled at an increase of 2～3℃ per minute, and stir continuously.
• 6.6 When the sample just changes from a transparent liquid into a white crystalline substance, immediately read the thermometer reading (read to 0.5℃); this temperature is the thermal decomposition temperature of the sample.

9. Qualitative and quantitative determination and calculation formula

• Qualitative criterion: the sample just changes from a transparent liquid into a white crystalline substance.
• Result calculation: take the arithmetic mean of two results from repeated determinations and round to an integer as the determination result.
• Calculation formula: not provided in the available source.

10. Precision

Judge the reliability of the test results according to the following provisions (95% confidence level).

• 7.1 Repeatability: for the same operator in the same laboratory, the difference between two repeated determination results shall not be greater than 3℃.
• 7.2 Reproducibility: for different operators in different laboratories, the difference between two determination results shall not be greater than 4℃.

11. Report

Take the arithmetic mean of two results from repeated determinations and round to an integer as the determination result.

12. Referenced documents

• GB/T 514 Technical conditions for liquid thermometers for petroleum product testing

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