ASTM D3238
Standard Test Method for Calculation of Carbon Distribution and Structural Group Analysis of Petroleum Oils by the n-d-M Method
| Organization: | ASTM |
| Publication Date: | 1 December 2017 |
| Status: | active |
| Page Count: | 3 |
| ICS Code (Petroleum products in general): | 75.080 |
scope:
This test method covers the calculation of the carbon distribution and ring content (Note 1) of olefin-free petroleum oils from measurements of refractive index, density, and molecular weight (n-d-M).2 This test method should not be applied to oils whose compositions are outside the following ranges:
In terms of carbon distribution-up to 75 % carbon atoms in ring structure; percentage in aromatic rings not larger than 1.5 times the percentage in naphthenic rings.
In terms of ring content-up to four rings per molecule with not more than half of them aromatic. A correction must be applied for oils containing significant quantities of sulfur.
NOTE 1-The composition of complex petroleum fractions is often expressed in terms of the proportions of aromatic rings (RA), naphthene rings (RN), and paraffin chains (CP) that would comprise a hypothetical mean molecule. Alternatively, the composition may be expressed in terms of a carbon distribution, that is, the percentage of the total number of carbon atoms that are present in aromatic ring structures (% CA), naphthene ring structures (% CN), and paraffin chains (% Cp).
The values stated in SI units are to be regarded as the standard.
Exception-The values in parentheses are for information only.
This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.
This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2 Van Nes, K., and van Westen, H. A., Aspects of the Constitution of Mineral Oils, Elsevier, New York, 1951.
*A Summary of Changes section appears at the end of this standard
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