These test methods cover the determination of hydroxyl groups
attached to primary and secondary carbon atoms in aliphatic and
alicyclic compounds and phenols.
Test Method A is recommended for general use. Test Method B is
included to give a standard procedure for the method that has been
used widely. Test Method C is recommended when the results are
required in a minimum period of time or where ambient temperature
for the reaction is desired.
The results obtained using Test Methods A and B will be
essentially the same, but the results obtained using Test Method C
will be higher (up to approximately 4 % relative) than those
obtained using the other two methods.
Statements on precision are included with each test method. The
precision of Test Methods A and C is consistent over a wide range
of hydroxyl content (tested over hydroxyl number range of 250 to
1600), whereas Test Method B is less precise at the higher hydroxyl
content level than it is at the lower hydroxyl content level. In
general, Test Method A is approximately two-fold as precise as Test
Method C. Test Method B has approximately the same precision as
Test Method C at the lower hydroxyl content level but poorer
precision at the higher hydroxyl content level.
The interferences are essentially the same for the three
methods. Some compounds can be analyzed using Test Methods A or B
but not using Test Method C because of interfering reactions of the
strong acid catalyst with the compound being analyzed or the
acetate product formed in the determination. However, because of
its increased reactivity, Test Method C is applicable for
determination of some compounds, particularly sterically hindered
secondary alcohols, which react too slowly or not at all in Test
Methods A and B.
The values stated in SI units are to be regarded as the
Review the current appropriate Material Safety Data Sheets
(MSDS) for detailed information concerning toxicity, first aid
procedures, and safety precautions.
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. Specific hazards statements are
given in Section 7.
NOTE 1 - Other methods for determination of hydroxyl groups are
given in Test Methods D 1957, D 2195, E 326, E 335, and E 567.
*A Summary of Changes section appears at the end of this
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