ASTM D1959-97 PDF

Full title and description

ASTM D1959-97 — Standard Test Method for Iodine Value of Drying Oils and Fatty Acids. A laboratory titrimetric procedure (Wijs method) for determining the iodine value (measure of unsaturation) of natural and synthetic drying oils and their fatty acids.

Abstract

This withdrawn ASTM test method specifies the Wijs iodometric titration procedure to measure the iodine value of drying oils and fatty acids. The method describes reagents, sample handling, reaction with Wijs reagent (iodine monochloride in acetic acid), quenching, iodide addition, and titration of liberated iodine with standardized sodium thiosulfate using a starch indicator. Results provide an empirical measure of unsaturation useful for quality control, formulation and comparative analysis; limitations for conjugated systems are noted (see Test Method D1541 for total iodine in conjugated samples).

General information

• Status: Withdrawn (withdrawal recorded February 27, 2006).
• Publication date: 1997 (designated D1959-97; commonly referenced as January 1, 1997).
• Publisher: ASTM International (formerly American Society for Testing and Materials).
• ICS / categories: 87.060.20 (Binders / Paints and related coatings).
• Edition / version: D1959-97 (1997 edition).
• Number of pages: Approximately 3 pages (short test method).

Scope

The standard covers the Wijs procedure for determination of unsaturation (iodine value) in drying oils and their fatty acids. It is applicable to most natural and synthetic drying oils and fatty acids but provides an empirical iodine value for materials with conjugated unsaturation (not a true total iodine value); for conjugated systems reference is made to Test Method D1541. The method is intended for laboratory use and includes safety cautions for hazardous reagents.

Key topics and requirements

• Use of Wijs reagent (iodine monochloride in acetic acid) to add halogen across double bonds.
• Reaction and quench procedure followed by addition of potassium iodide to liberate iodine.
• Titration of liberated iodine with standardized sodium thiosulfate, using starch as an indicator.
• Calculation of iodine value (g I2 per 100 g sample) from titration data and reagent normality.
• Statement of applicability and limitation for conjugated unsaturation (recommendation to use D1541 for total iodine in such cases).
• Safety and handling notes for hazardous reagents (acetic acid, iodine reagents and halogen-containing reagents).

Typical use and users

Used by analytical and quality-control laboratories in coatings, paint, varnish and lubricant industries, by raw material suppliers of drying oils and fatty acids, by research and academic labs studying oil unsaturation, and by formulators needing a comparative measure of unsaturation for process control, specification compliance or product development.

Related standards

Related ASTM and test methods include: Test Method D1541 (Total Iodine Value for conjugated systems), D2075 and D2078 (equivalent or related iodine-value methods), and more recent/alternative methods for iodine value of fats and oils such as D5554. The method originated under Committee D01 (paints and related coatings) and is referenced by a number of other D01 series documents.

Keywords

iodine value; Wijs method; drying oils; fatty acids; unsaturation; titration; iodine monochloride; sodium thiosulfate; paint binders; quality control.

FAQ

Q: What is this standard?

A: ASTM D1959-97 is a test method that describes the Wijs iodometric titration procedure for determining the iodine value (an empirical measure of unsaturation) of drying oils and fatty acids.

Q: What does it cover?

A: It covers reagents, sample handling, reaction with Wijs reagent, quenching and iodide addition, titration with sodium thiosulfate using a starch indicator, calculation of iodine value, and limitations for conjugated systems.

Q: Who typically uses it?

A: Analytical and QC laboratories in coatings, paint and lubricant industries, raw material suppliers, formulators, and academic researchers evaluating degree of unsaturation in oils and fatty acids.

Q: Is it current or superseded?

A: The standard was withdrawn (withdrawal recorded February 27, 2006). It is therefore not current; other ASTM methods (for example D1541 for total iodine in conjugated systems and later or alternative iodine-value methods) may be used depending on the application.

Q: Is it part of a series?

A: Yes — it was issued under ASTM Committee D01 (paints and related coatings) and sits among a family of iodine-value and oil-unsaturation test methods (for example D1541, D2075, D2078 and related D01 test methods).

Q: What are the key keywords?

A: Iodine value, Wijs method, drying oils, fatty acids, unsaturation, titration, paint binders, quality control.