ASTM D3238-17a

Standard Test Method for Calculation of Carbon Distribution and Structural Group Analysis of Petroleum Oils by the n-d-M Method

SIGNIFICANCE AND USE
4.1 The carbon distribution and ring content serve to express the gross composition of the heavier fractions of petroleum. These data can be used as an adjunct to the bulk properties in monitoring the manufacture of lubricating oil base stocks by distillation, solvent refining or hydrogenation, or both, and in comparing the composition of stocks from different crude sources. Furthermore, the data can often be correlated with critical product performance properties.
SCOPE
1.1 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:  
1.1.1 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.  
1.1.2 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).  
1.2 The values stated in SI units are to be regarded as the standard.  
1.2.1 Exception—The values in parentheses are for information only.  
1.3 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.  
1.4 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.

General Information

• Status: Historical
• Publication Date: 30-Nov-2017
• ICS: 75.080 - Petroleum products in general
• Technical Committee: D02 - Petroleum Products, Liquid Fuels, and Lubricants
• Drafting Committee: D02.04.0K - Correlative Methods

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: D3238 − 17a
Standard Test Method for
Calculation of Carbon Distribution and Structural Group
1
Analysis of Petroleum Oils by the n-d-M Method
This standard is issued under the fixed designation D3238; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope* 2. Referenced Documents
3
1.1 This test method covers the calculation of the carbon
2.1 ASTM Standards:
distribution and ring content (Note 1) of olefin-free petroleum
D1218 Test Method for Refractive Index and Refractive
oils from measurements of refractive index, density, and
Dispersion of Hydrocarbon Liquids
2
molecular weight (n-d-M). This test method should not be
D1480 Test Method for Density and Relative Density (Spe-
applied to oils whose compositions are outside the following
cific Gravity) of Viscous Materials by Bingham Pycnom-
ranges:
eter
1.1.1 In terms of carbon distribution—up to 75 % carbon
D1481 Test Method for Density and Relative Density (Spe-
atoms in ring structure; percentage in aromatic rings not larger
cific Gravity) of Viscous Materials by Lipkin Bicapillary
than 1.5 times the percentage in naphthenic rings.
Pycnometer
1.1.2 Intermsofringcontent—uptofourringspermolecule
D1552 Test Method for Sulfur in Petroleum Products by
with not more than half of them aromatic.Acorrection must be
High Temperature Combustion and Infrared (IR) Detec-
applied for oils containing significant quantities of sulfur.
tion or Thermal Conductivity Detection (TCD)
NOTE 1—The composition of complex petroleum fractions is often
D2502 Test Method for Estimation of Mean Relative Mo-
expressed in terms of the proportions of aromatic rings (R ), naphthene
A
lecular Mass of Petroleum Oils from Viscosity Measure-
rings (R ), and paraffin chains (C ) that would comprise a hypothetical
N P
ments
mean molecule.Alternatively, the composition may be expressed in terms
of a carbon distribution, that is, the percentage of the total number of D2503 TestMethodforRelativeMolecularMass(Molecular
carbon atoms that are present in aromatic ring structures (% C ),
A Weight) of Hydrocarbons by Thermoelectric Measure-
naphthene ring structures (% C ), and paraffin chains (% C ).
N p
ment of Vapor Pressure
1.2 The values stated in SI units are to be regarded as the
D2622 Test Method for Sulfur in Petroleum Products by
standard.
Wavelength Dispersive X-ray Fluorescence Spectrometry
1.2.1 Exception—Thevaluesinparenthesesareforinforma-
D4052 Test Method for Density, Relative Density, and API
tion only.
Gravity of Liquids by Digital Density Meter
1.3 This standard does not purport to address all of the
D4294 Test Method for Sulfur in Petroleum and Petroleum
safety concerns, if any, associated with its use. It is the
Products by Energy Dispersive X-ray Fluorescence Spec-
responsibility of the user of this standard to establish appro-
trometry
priate safety, health, and environmental practices and deter-
mine the applicability of regulatory limitations prior to use.
3. Summary of Test Method
1.4 This international standard was developed in accor-
3.1 The refractive index and density of the oil are deter-
dance with internationally recognized principles on standard-
mined at 20 °C. The molecular weight is determined experi-
ization established in the Decision on Principles for the
mentally or estimated from measurements of viscosity at
Development of International Standards, Guides and Recom-
37.8 °C and 98.89 °C (100 °F and 210 °F). These data are then
mendations issued by the World Trade Organization Technical
used to calculate the carbon distribution (% C ,% C ,% C )
Barriers to Trade (TBT) Committee.
A N P
or the ring analysis (R , R ) using the appropriate set of
A N
equations.
1
This test method is under the jurisdiction of ASTM Committee D02 on
Petroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility of
Subcommittee D02.04.0K on Correlative Methods.
Current edition approved Dec. 1, 2017. Published December 2017. Originally
3
approved in 1973. Last previous edition approved in 2017 as D3238 – 17. DOI: For referenced ASTM standards, visit the ASTM website, www.astm.org, or
10.1520/D3238-17A. contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
2
Van Nes, K., and van Westen, H. A., Aspects of the Constitution of Mineral Standards volume information, refer to the standard’s Document Summary page on
Oils, Elsevier, New York, 1951. the ASTM website.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United
...

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: D3238 − 17 D3238 − 17a
Standard Test Method for
Calculation of Carbon Distribution and Structural Group
1
Analysis of Petroleum Oils by the n-d-M Method
This standard is issued under the fixed designation D3238; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope*
1.1 This test method covers the calculation of the carbon distribution and ring content (Note 1) of olefin-free petroleum oils from
2
measurements of refractive index, density, and molecular weight (n-d-M). This test method should not be applied to oils whose
compositions are outside the following ranges:
1.1.1 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.
1.1.2 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 (R ), naphthene rings (R ),
A N
and paraffin chains (C ) that would comprise a hypothetical mean molecule. Alternatively, the composition may be expressed in terms of a carbon
P
distribution, that is, the percentage of the total number of carbon atoms that are present in aromatic ring structures (% C ), naphthene ring structures (%
A
C ), and paraffin chains (% C ).
N p
1.2 The values stated in SI units are to be regarded as the standard.
1.2.1 Exception—The values in parentheses are for information only.
1.3 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 safety, health, and healthenvironmental practices and determine the
applicability of regulatory limitations prior to use.
1.4 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. Referenced Documents
3
2.1 ASTM Standards:
D1218 Test Method for Refractive Index and Refractive Dispersion of Hydrocarbon Liquids
D1480 Test Method for Density and Relative Density (Specific Gravity) of Viscous Materials by Bingham Pycnometer
D1481 Test Method for Density and Relative Density (Specific Gravity) of Viscous Materials by Lipkin Bicapillary Pycnometer
D1552 Test Method for Sulfur in Petroleum Products by High Temperature Combustion and Infrared (IR) Detection or Thermal
Conductivity Detection (TCD)
D2502 Test Method for Estimation of Mean Relative Molecular Mass of Petroleum Oils from Viscosity Measurements
D2503 Test Method for Relative Molecular Mass (Molecular Weight) of Hydrocarbons by Thermoelectric Measurement of
Vapor Pressure
D2622 Test Method for Sulfur in Petroleum Products by Wavelength Dispersive X-ray Fluorescence Spectrometry
D4052 Test Method for Density, Relative Density, and API Gravity of Liquids by Digital Density Meter
D4294 Test Method for Sulfur in Petroleum and Petroleum Products by Energy Dispersive X-ray Fluorescence Spectrometry
1
This test method is under the jurisdiction of ASTM Committee D02 on Petroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility of Subcommittee
D02.04.0K on Correlative Methods.
Current edition approved June 1, 2017Dec. 1, 2017. Published June 2017December 2017. Originally approved in 1973. Last previous edition approved in 20152017 as
D3238 – 95 (2015).D3238 – 17. DOI: 10.1520/D3238-17.10.1520/D3238-17A.
2
Van Nes, K., and van Westen, H. A., Aspects of the Constitution of Mineral Oils, Elsevier, New York, 1951.
3
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

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