SH/T 0258-1992 Determination of Color of Lubricating Oils

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

• Standard number: SH/T 0258-92
• Full name: Determination of Color of Lubricating Oils
• English name: not provided in the available source
• Replacement relationship: replaces SY 2614-56(88)
• Other: confirmed in 2004; approved by China Petrochemical Corporation 1992-05-20, implemented in 1992-05-20
• Reference adoption: former Soviet Union national standard ГОСТ 2667-52 "Method for Determination of Color of Petroleum Products"

2. Scope of application and non-applicability

• This standard specifies a method for determining the color of lubricating oils.
• Applicable to determining the depth of color of lubricating oils with Engler viscosity above E50=1.3.
• Not applicable to determining hue and fluorescence.
• The color of lubricating oil indicates a characteristic of the degree of removal of hydrocarbon oxides and sulfides in the lubricating oil.

3. Method principle

The sample is compared with standard glass color plates, or with the color of a pre-selected iodine standard solution at a certain height; the result is expressed as the height in millimeters of the oil column consistent with the standard color concentration.

4. Reagents and materials (purity / preparation)

• 4.1 Iodine: analytical reagent.
• 4.2 Potassium iodide: chemical reagent.
• 4.3 Sodium thiosulfate: analytical reagent, prepared as c(Na2S2O3)=0.1 mol/L sodium thiosulfate standard titration solution.
• Preparation of standard solution (5.3):
  • Use 1 mL solution containing 0.507 mg pure iodine as the standard solution.
  • Preparation of pure iodine: take crystalline iodine 2～3 g and mix with colorless potassium iodide 0.2～0.3 g, then sublimate; place the sublimated iodine in a desiccator containing sodium hydroxide and dry for 24 h.
  • Weigh about 1.27 g of sublimated and dried iodine: dissolve about 7 g of colorless potassium iodide in 10 mL of water in a weighing bottle; after weighing, add about 1.27 g of sublimated and dried crystalline iodine, cover the lid, weigh again, and determine the mass of iodine by difference.
  • Transfer all the solution in the weighing bottle to a 100 mL volumetric flask, and add distilled water to the mark; its concentration is about c(½I2)=0.1 mol/L.
  • Use a pipette to take 10 mL of this iodine solution, and calibrate with c(Na2S2O3)=0.1 mol/L sodium thiosulfate standard titration solution to obtain the concentration of the prepared iodine standard titration solution c(½I2), in units of moles per liter.
  • The concentration A (g/mL) of the iodine standard solution is converted according to formula (1):
    • A = (c × 126.9) / 1000
    • Where: c— the actual concentration of the prepared iodine standard titration solution, mol/L; 126.9— the mass of 1 mol iodine with the basic unit as (½I2), g/mol.
  • To prepare an iodine standard solution with a concentration of 1 mL solution containing 0.507 mg pure iodine at 500 mL, the required volume B (mL) of the iodine standard solution prepared according to the above procedure is calculated according to formula (2):
    • B = 0.2535 / A
    • Where: 0.2535— the mass of iodine contained in the iodine standard solution at 500 mL concentration of 1 mL containing 0.507 mg, g; A— the actual concentration of the above-prepared iodine standard solution, g/mL.
  • Place B milliliters of the above-prepared iodine standard solution from a burette into a 500 mL volumetric flask, and add distilled water to the mark; the measured concentration of the solution may vary within the range of 0.000505～0.000510 g/mL.
  • This standard solution should be stored in a brown glass bottle in a dark place; its concentration should be checked at least once every ten days with c(Na2S2O3)=0.004 mol/L sodium thiosulfate standard titration solution.
• Note: Some chemical formulas and symbols are garbled in the source transcription. The displayed interpretations were inferred from context and remain unverified; check the chemical identities, formulas and calculation symbols against the original before use.

5. Instruments and equipment

• 3.1 Kuboske-type colorimeter: there are two small cups; the upper part is enlarged and the lower part is a cylindrical glass tube with a threaded metal ring; on the metal ring at the lower part of the tube, a cup bottom made of colorless glass with a metal ring can be screwed on. Each small cup is mounted on a horizontal base; this horizontal base, together with a vernier 6 with graduations (10 graduations each of 9 mm), is moved up and down by a rack 5 along two vertical grooves 4 on the outer casing of the device. On the upper part of the device, two vertically fixed downward-hanging prisms or two cylinders 1 are fixed, whose diameter is slightly smaller than the diameter of the cup, so that the cylinders do not contact the cup wall and can freely enter the small cups. When the small cups move upward from below, the cylinders, prisms, or bottom ends can touch the cup bottom.
  • Component labels: 1- cylinder; 2- small cup; 3- reflector; 4- vertical groove; 5- rack; 6- vernier; 7- prism; 8- standard glass color plate; 9, 10- lenses; 11- eyepiece.
  • Another construction: a fixed small cup base is installed, and the glass cylinder is moved by a rack 5. The outer casing of the device is equipped with two scales (each graduated in millimeters) for determining the distance from the bottom end of the cylinder to the bottom of the small cup. On each horizontal base, a standard glass color plate can be installed, whose diameter must match the bottom of the small cup, and its position also corresponds to the position of the bottom of the small cup. In a special Kuboske-type colorimeter, the standard glass color plate 8 is inserted into a specially provided slit.
  • The frosted glass or opal glass reflector 3 fixed at the lower part of the device can rotate about a horizontal axis to change its inclination to reflect scattered daylight. The light reflected by the reflector and passing through the compared liquid column or standard glass color plate reaches the optical device composed of prism 7, lenses 9 and 10, and eyepiece 11, and is gathered in the field of view of the eyepiece.
• 3.2 Volumetric flask: 100, 500 mL.
• 3.3 Pipette: 10 mL.
• Note: In 3.2, "500mLa", and in 3.3, "IOML" are source-text extraction noise, which have been restored according to semantics as 500 mL, 10 mL, and require confirmation against the source standard (source-text extraction).

6. Recommended operating conditions

not provided in the available source (no clauses on operating conditions such as temperature, pressure, flow rate, etc.).

7. Sampling and sample preparation

• 5.1 The lubricating oil for the test must be completely transparent and free of mechanical impurities.
• 5.2 Calibration of the scale: inject standard solution 10 mL into each of the two small cups, then place the two small cups on the base of the colorimeter. Use the rack to move the two small cups so that the two cylinders are immersed in the liquid; continue adjusting the positions of the two small cups with the rack while observing through the eyepiece so that the colors of the two halves of the field of view are completely consistent. Using the scale and vernier on the device, determine the height of each liquid column; the difference between the results should not exceed 0.2 mm. From the results of three consecutive measurements, obtain the average difference in units of 1/10 mm, which is used as the correction value for the oil column height in subsequent determinations of lubricating oil color.
• 5.4 Installation of the colorimeter: before determining the color of the sample, wash the glass cylinders with gasoline and dry them with filter paper. If necessary, wipe the eyepiece with clean chamois leather or flannel. The small cups carefully washed with gasoline are then rinsed with distilled water; they need not be wiped and can be placed in a desiccator to dry. Raise the small cups placed in the colorimeter until their bottoms contact the cylinders. This colorimeter should be placed on a platform so that the small cups are strictly vertical and scattered daylight falls on the reflector. Then look into the eyepiece while adjusting the reflector until the two halves of the field of view have the same brightness, and the double scale also points to zero, ready for the test.
• 5.5 Inspection of the glass color plate: carefully avoid moving the device from its original position, and remove the two small cups. Place an appropriate standard glass color plate on the horizontal base of the device, replacing the left small cup, so that it exactly fits the working position of the bottom of the small cup; use the rack to raise the base with the glass color plate until it contacts the bottom end of the cylinder opposite it. Inject iodine standard solution into the right small cup. Use the rack to raise the right base together with the small cup until the height of the iodine standard solution column, according to the scale and vernier, is exactly equal to 13 mm. Look into the eyepiece; the colors of the two halves of the field of view should be completely consistent. If the glass cylinders are movable and the bases are fixed, then before looking into the eyepiece, the left cylinder must be lowered to contact the glass color plate, and the right cylinder must be lowered to a distance of 13 mm from the cup bottom.

8. Analysis procedure

• 6.1 On the left base of the instrument, place the standard glass color plate as described above. Inject the sample into the right small cup; place the small cup containing the sample on the right base, and while looking into the eyepiece, use the rack to raise the small cup until the color concentrations of the two halves of the field of view are consistent.
• 6.2 If the cylinders are movable and the bases are fixed, then before the final reading, adjust the left hanging object until the positions of the two hanging objects are consistent.
• 6.3 Record the reading in millimeters according to the scale and vernier. After letting the eyes rest briefly, change the position of the small cup containing the sample, and repeat the observation twice.

9. Qualitative and quantitative determination and calculation formulas

• Expression of results: expressed as the height in millimeters of the oil column consistent with the standard color concentration.
• Calculation formulas:
  • Formula (1): A = (c × 126.9) / 1000
    • A— concentration of iodine standard solution, g/mL
    • c— actual concentration of the prepared iodine standard titration solution, mol/L
    • 126.9— mass of 1 mol iodine with the basic unit as (½I2), g/mol
  • Formula (2): B = 0.2535 / A
    • B— volume of iodine standard solution required to be prepared, mL
    • 0.2535— mass of iodine contained in the iodine standard solution at 500 mL concentration of 1 mL containing 0.507 mg, g
    • A— actual concentration of the above-prepared iodine standard solution, g/mL
• Note: Some symbols in the original formulas contain source-text extraction noise, requiring confirmation against the source standard (source-text extraction).

10. Precision

The difference between the results of three observations of the same sample should not exceed the following values:

Note: In the original text, “1 0.5” and “t 1.5” are source-text extraction noise, and have been restored semantically to ±0.5 and ±1.5; requires confirmation against the source standard (source-text extraction).

11. Report

Take the arithmetic mean of three observation results of the same test sample as the determination result of the test sample.

12. Normative references

not provided in the available source (the main text does not list the normative references).

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