ASTM D721-17 PDF

Full title and description

ASTM D721-17 — Standard Test Method for Oil Content of Petroleum Waxes. This test method specifies a solvent‑extraction procedure (commonly using methyl ethyl ketone, MEK) and gravimetric determination to measure the weight percent of oil (solvent‑extractable material) in petroleum waxes with congealing points of 30 °C (86 °F) or higher and nominal oil contents up to about 15%.

Abstract

ASTM D721-17 provides a laboratory procedure to determine oil (solvent‑extractable) content of solid petroleum waxes. A precisely weighed molten sample is treated with MEK, the oil‑containing solvent is separated from the solid wax (using the specified filter stick/test tube assembly), the solvent is evaporated, and the residue is weighed to calculate percent oil. The method notes limitations for waxes with higher oil content (>5%) where phase incompatibility can occur.

General information

• Status: Superseded (revised by ASTM D721-25 in 2025); D721-17 remains a published historical edition.
• Publication date: Current edition approved May 1, 2017; published June 2017 (designation D721‑17).
• Publisher: ASTM International (formerly American Society for Testing and Materials).
• ICS / categories: Petroleum products; Test methods for materials; Lubricants and waxes; Laboratory analytical methods.
• Edition / version: D721‑17 (2017 edition).
• Number of pages: 7 pages (typical published PDF of the 2017 edition).

Scope

This test method covers determination of oil in petroleum waxes having a congealing point of 30 °C (86 °F) or higher and containing not more than about 15% oil. It is intended for waxes where the oil is soluble in the specified solvent (MEK). Note: some waxes with oil contents greater than ~5% may form two liquid phases with MEK and thus fall outside the method’s applicability.

Key topics and requirements

• Sample preparation: melt representative portion (70–100 °C), mix and transfer a controlled mass (typically 1.00 ± 0.05 g) into the test tube.
• Solvent extraction: add specified volume of methyl ethyl ketone (about 15 mL), heat and stir to produce a homogeneous solution of solvent + oil.
• Separation: use the standard filter‑stick/test‑tube filtration assembly to separate solvent/oil from solid wax.
• Evaporation and gravimetry: evaporate solvent under the prescribed evaporation assembly/conditions, dry residue, and determine mass of extracted oil to the required balance precision.
• Calculation and reporting: calculate weight percent oil in the original wax sample and report method conditions, any deviations, and observed incompatibilities (e.g., phase separation with MEK).
• Apparatus and reagents: filter stick, cooling bath, evaporation assembly, analytical balance (0.1 mg reproducibility), MEK (analytical reagent grade) stored/dried over desiccant as specified.
• Limitations: not suitable when MEK and wax/oil phase behavior is incompatible (notably for some waxes with higher oil fractions); recommended for oils up to ~15% and most reliable below ~5% where no phase separation occurs.

Typical use and users

Used primarily by quality control and analytical laboratories in wax and petrochemical manufacturing, candle and cosmetic producers, lubricant and wax formulation labs, and third‑party testing services. Typical applications include routine QC of paraffin and microcrystalline waxes, specification testing for suppliers and purchasers, regulatory/compliance checks (where oil content is a regulated property), and R&D when formulating wax‑based products.

Related standards

Commonly referenced and complementary standards include ASTM D938 (Congealing Point of Petroleum Waxes), ASTM D87 / D127 (melting/softening point tests for waxes), ISO and IP equivalents for solvent extractables (for example ISO 2908 / IP 158 where applicable), and internal or industry‑specific methods for wax properties and appearance.

Keywords

petroleum wax; oil content; solvent extraction; methyl ethyl ketone (MEK); filter stick; gravimetric; congealing point; wax testing; ASTM D721; quality control.

FAQ

Q: What is this standard?

A: ASTM D721‑17 is the 2017 edition of the ASTM test method that defines a solvent‑extraction and gravimetric procedure to determine oil (solvent‑extractable) content in petroleum waxes.

Q: What does it cover?

A: It covers laboratory procedures for measuring oil content in petroleum waxes with congealing points ≥30 °C and nominal oil contents up to about 15%, including required apparatus, reagents (typically MEK), stepwise procedure, calculation, and limitations.

Q: Who typically uses it?

A: QC and R&D laboratories in wax, candle, cosmetic, lubricant, and petrochemical industries; suppliers and purchasers who verify wax composition; third‑party testing labs performing specification or regulatory testing.

Q: Is it current or superseded?

A: The D721‑17 text is the 2017 edition. It has since been revised; the D721‑25 revision (published in 2025) supersedes D721‑17. Users requiring the currently active procedure should consult the latest ASTM designation (D721‑25 as of 2025).

Q: Is it part of a series?

A: D721 is part of the ASTM family of petroleum product and lubricant test methods developed by Committee D02 (Subcommittee D02.10 on properties of petroleum waxes and alternative wax‑like materials). It is often used alongside other wax test methods (D938, D87, D127, etc.).

Q: What are the key keywords?

A: Petroleum wax, oil content, solvent extraction, MEK, filter stick, gravimetric determination, congealing point, ASTM D721.