ASTM D2007 Test Method for Characteristic Groups in Rubber Extender and Processing Oils and Other Petroleum-Derived Oils

Scope:

ASTM D2007 is a standard test technique for characteristic groups in rubber extender and processing oils, as well as other petroleum-derived oils by the clay-gel absorption chromatographic method. The composition of the oil used in rubber compounds has a significant impact on the properties and applications of the compounds. The composition of the saturates, aromatics, and polar compounds is the key analysis in the measurements. These determinations, as well as any subsequent examination of the fractions produced, are frequently utilized as a research approach to better understand the impacts of oil in rubber and other applications.

Test Procedure:

For ASTM D2007, the sample is diluted with solvent and charged to a glass percolation column containing clay in the top area and silica gel plus clay in the lower section. The upper (clay) section is separated from the lower section and washed again with n-pentane. The clay part is subsequently charged with a 50/50 toluene-acetone mixture for desorption, and a defined volume of effluent is collected. The solvents are entirely removed from the recovered n-pentane and toluene-acetone fractions, and the residues are weighed and estimated as saturate and polar compound concentrations. Aromatics can be calculated by difference or measured after evaporation of the toluene used for desorption of the gel column.

Video 01: How It’s Made – Crude Oil

Specimen Size:

Oil samples, such as petroleum-derived oils, are utilized as test specimens in ASTM D2007 test technique. A sample of 10 ± 0.5 g is used.

Data:

As per the ASTM D2007, the amount of n-pentane insolubles, saturates, aromatics, and polar compounds in the sample is calculated as follows: 

• Saturates, mass % = (B/A) × 100
• Aromatics, mass % = (C/A) × 100
• Polar compounds, for 10 g sample = (D/A) x 100
• Polar compounds, mass % for 5 g sample = [(0.88 × D/A)] × 100 

Where A, B, C, and D, are the grams of original sample, residue from n-pentane effluent from the clay gel column, residue from the toluene desorption of the lower column and from the last n-pentane rinse of the columns, and residue from toluene-acetone effluent, respectively.

Conclusion: 

ASTM D2007 test method specifies a protocol for classifying oil samples with an initial boiling point of at least 260 °C.  This test technique is used for characteristic groups in rubber extender and processing oils, as well as other petroleum-derived oils by the clay-gel absorption chromatographic method.