Hydroxyl is an important functional group and knowledge of its content is required in many intermediate and end use applications. This test method is for the determination of primary and secondary hydroxyl groups and can be used for the assay of compounds containing them.

This test method has the following advantages over other hydroxyl number methods: It is rapid (10 min), pyridine-free, ambient temperature, small sample size, applicable to extremely low hydroxyl numbers (<1), and is amenable to automation.

1. Scope

1.1 This test method covers the determination of hydroxyl groups attached to primary and secondary carbon atoms in aliphatic and cyclic compounds and phenols. It is not suitable for determination of hydroxyl groups attached to tertiary carbon atoms. This test method is applicable to polyacetals, temperature sensitive materials, high solids polymer polyols, and rigid polyols. Other available test methods listed in Note 1 are not suitable for many of the sample types listed above.

1.1.1 This test method is currently recommended for neutral refined products. Successful application has been made, however, to some in-process samples that contain an excess of acidic species. Proper validation must be performed, of course, to show that the acidic species either does not interfere, or that the acidic species interference has been obviated.

Note 1—Other methods for determination of hydroxyl groups are given in Test Methods D 817, D 871, D 1957, D 2195, D 4252, D 4273, D 4274, E 222, E 326, and E 335.

1.2 Review the current appropriate Material Safety Data Sheets (MSDS) for detailed information concerning toxicity, first aid procedures, and safety precautions.

1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.

1.4 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.

For specific hazards see Section 9.

2. Referenced Documents (purchase separately) The documents listed below are referenced within the subject standard but are not provided as part of the standard.

ASTM Standards

D817 Test Methods of Testing Cellulose Acetate Propionate and Cellulose Acetate Butyrate

D871 Test Methods of Testing Cellulose Acetate

D1193 Specification for Reagent Water

D1957 Test Method for Hydroxyl Value of Fatty Oils and Acids

D2195 Test Methods for Pentaerythritol

D4252 Test Methods for Chemical Analysis of Alcohol Ethoxylates and Alkylphenol Ethoxylates

D4273 Test Method for Polyurethane Raw Materials: Determination of Primary Hydroxyl Content of Polyether Polyols

D4274 Test Methods for Testing Polyurethane Raw Materials: Determination of Hydroxyl Numbers of Polyols

E180 Practice for Determining the Precision of ASTM Methods for Analysis and Testing of Industrial and Specialty Chemicals

E222 Test Methods for Hydroxyl Groups Using Acetic Anhydride Acetylation

E300 Practice for Sampling Industrial Chemicals

E326 Test Method for Hydroxyl Groups by Phthalic Anhydride Esterification (Discontinued 2001)

E335 Test Method for Hydroxyl Groups by Pyromellitic Dianhydride Esterification

Keywords

hydroxyl number; p-Toluenesulfonyl isocyanate; polyacetals; polyols; potentiometric titration; tetrabutylammonium hydroxide; Hydroxyl groups; Potentiometric titration; Tetrabutylammonium hydroxide; p-Toluenesulfonyl isocyanate (TSI);

ICS Code

ICS Number Code 71.040.40 (Chemical analysis)

Citing ASTM Standards

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