ASTM D2668-02e1
(Test Method)Standard Test Method for 2,6-di-tert-Butyl- p-Cresol and 2,6-di-tert-Butyl Phenol in Electrical Insulating Oil by Infrared Absorption
Standard Test Method for 2,6-<i>di-tert</i>-Butyl-<i> p</i>-Cresol and 2,6-<ital>di-tert</ital>-Butyl Phenol in Electrical Insulating Oil by Infrared Absorption
SCOPE
1.1 This test method covers the determination of the weight percent of 2,6-ditertiary-butyl paracresol and 2,6-ditertiary-butyl phenol in new or used electrical insulating oil in concentrations up to 0.5 % by measuring its absorbance at the specified wavelengths in the infrared spectrum.
1.2 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 and health practices and determine the applicability of regulatory limitations prior to use.
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Designation:D 2668–02
Standard Test Method for
2,6-di-tert-Butyl-p-Cresol and 2,6-di-tert-Butyl Phenol in Electrical
1
Insulating Oil by Infrared Absorption
This standard is issued under the fixed designation D 2668; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1 −1 −1
e NOTE—TheabsorbanceofDBPCandDBPwascorrectedfrom3680cm to3650cm in3.2editoriallyinNovember2005.
1. Scope* an increase in absorbance of the spectrum at several wave-
lengths (or wavenumbers). 2,6 ditertiary-butyl paracresol pro-
1.1 This test method covers the determination of the weight
duces pronounced increases in absorbance at 2.72 µm (3650
percent of 2,6-ditertiary-butyl paracresol and 2,6-ditertiary-
−1 −1
cm ), and 11.63 µm (860 cm ). 2,6 ditertiary-butyl phenol
butyl phenol in new or used electrical insulating oil in
producespronouncedincreasesinabsorbanceat2.72µm(3650
concentrations up to 0.5% by measuring its absorbance at the
−1 −1
cm ) and 13.33 µm (750 cm ).
specified wavelengths in the infrared spectrum.
3.3 When making this test on other than a highly oxidized
1.2 This standard does not purport to address all of the
oil or when using a double-beam spectrophotometer, it has
safety concerns, if any, associated with its use. It is the
been found convenient to obtain the spectrum between 2.5 µm
responsibility of the user of this standard to establish appro-
−1 −1
(4000cm )and2.9µm(3450cm )becausetheinstrumentis
priate safety and health practices and determine the applica-
compensated for the presence of moisture and the band is not
bility of regulatory limitations prior to use.
influenced by intermolecular forces (associations). However,
2. Referenced Documents
whentestingahighlyoxidizedoilorwhenusingasingle-beam
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instrument better results may be obtained if the scan is made
2.1 ASTM Standards:
−1 −1
between 10.90 µm (918 cm ) and 14.00 µm (714 cm ).
D923 Practices for Sampling Electrical Insulating Liquids
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3.4 Increased absorption at 11.63 µm (860 cm ) or 13.33
D2144 Test Methods for Examination of Electrical Insulat-
−1
µm (750 cm ) or both, will identify the inhibitor as 2,6-
ing Oils by Infrared Absorption
ditertiary-butyl paracresol or 2,6-ditertiary-butyl phenol re-
D3487 Specification for Mineral Insulating Oil Used in
spectively (Note 1).
Electrical Apparatus
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NOTE 1—The absorbance at 750 cm for 2,6-ditertiary-butyl phenol
3. Significance and Use
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and at 860 cm for 2,6-ditertiary-butyl paracresol for equal concentra-
3.1 The quantitative determination of 2,6-ditertiary-butyl tions will be in the approximate ratio of 2.6 to 1.
paracresol and 2,6-ditertiary-butyl phenol in a new electrical
4. Apparatus
insulating oil measures the amount of this material that has
4.1 Withequipmentdescriptionreferringtocompliance,the
been added to the oil as protection against oxidation. In a used
equipment shall be in accordance with Section 6 of Test
oil it measures the amount remaining after oxidation products
Methods D2144. Accordingly, the use of Fourier-transform
have reduced its concentration. The test is also suitable for
rapid scan infrared spectrophotometers is permitted by refer-
manufacturing control and specification acceptance.
ence to that test method.
3.2 When an infrared spectrum is obtained of an electrical
insulating oil inhibited with either of these compounds there is
5. Sampling
5.1 Obtain the sample in accordance with Test Method
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This test method is under the jurisdiction of ASTM Committee D27 on
D923.
Electrical Insulating Liquids and Gases and is the direct responsibility of Subcom-
mittee D27.03 on Analytical Tests.
6. Calibration and Standardization
Current edition approved Oct. 10, 2002. Published December 2002. Originally
published as D2668–67. Last previous edition D2668–96. 6.1 Whenthemanufactureroftheoilisknownandthebase
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
oil is available, use it to prepare the standards. For oils of
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
unknown origin, use base oils which meet the requirements of
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.
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D 2668–02
Specification D3487. Some base oils may provide a better test specimen may be determined. One such calibration curve
match than others and therefore it is desirable
...
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