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D2694-05 – Standard Test Method Technical Guide
ASTM D2694-05 (Reapproved 2019) establishes the standard specification for diethylene glycol (2,2’oxydiethanol) intended for use in the preparation of surface coatings. This document defines the required purity, physical properties, and test methods necessary for evaluating compliance, ensuring a high-quality chemical intermediate for industrial applications.
📐 Scope and Referenced Standards
This specification governs diethylene glycol specifically for surface coatings. All property limits are intended for evaluation in SI units. As stipulated in Section 1.2, conformance requires that observed or calculated values be rounded “to the nearest unit” of the specification limit, following the rules of Practice E29. The standard relies on several critical ASTM methods for evaluation, including Test Methods E202 for glycol analysis, D1209 and D5386 for color measurement, D4052 for density, and Practice E300 for sampling. Packaging must comply with U.S. Federal Specification PPP-C-2020. Users are also directed to consult the supplier’s Material Safety Data Sheet for specific hazard information.
⚙️ Chemical and Physical Property Requirements
Diethylene glycol meeting this specification must conform to the specific limits outlined in Section 3.1. These stringent requirements ensure the material is suitable for high-performance surface coating formulations.
| 🎯 Property | 📏 Specification Limit | ⚡ Test Method |
|---|---|---|
| Apparent Specific Gravity (20/20 °C) | 1.1170 to 1.1200 | Test Methods E202 |
| Apparent Specific Gravity (25/25 °C) | 1.1147 to 1.1177 | Test Methods E202 |
| Color, Pt-Co units, max | 15 | Test Methods D1209 or D5386 |
| Distillation Range (760 mm Hg) | Initial B.P., min: 240 °C Dry Point, max: 250 °C |
Test Methods E202 |
| Water, wt %, max | 0.2 | Test Methods E202 |
| Acidity (as acetic acid), wt %, max | 0.01 | Test Methods E202 |
| Ethylene Glycol, wt %, max | 0.5 | Test Methods E202 |
| Triethylene Glycol, wt %, max | 1.0 | Test Methods E202 |
| Iron, ppm, max | 1.0 | Test Methods E202 |
💡 Note on Specific Gravity: While Test Methods E202 is the primary referee method for specific gravity, Test Method D4052 (using a digital density meter) may also be used to determine the apparent specific gravity of the diethylene glycol sample.
⚠️ Rounding for Compliance: Per Section 1.2 of D2694, to determine conformance with this specification, observed or calculated values must be rounded “to the nearest unit” in the last right-hand digit of the specification limit, strictly following the guidelines of Practice E29.
📊 Sampling, Test Methods, and Compliance
Proper and representative sampling is the first step in verifying quality. Section 4 of the standard mandates that sampling must be conducted in accordance with Practice E300, which covers the sampling of industrial chemicals. Section 5 defines the test methods for certifying compliance. All properties listed in the specification must be determined by the procedures detailed in Test Methods E202. For color assessment, Test Method D5386 (Instrumental Tristimulus Colorimetry) provides an alternative to the visual comparison method described in D1209. Although general interlaboratory studies have shown no significant statistical difference between these two methods, the specification notes it is unknown if diethylene glycol was explicitly part of that study’s sample set.
❓ Frequently Asked Questions
🔍 What is the primary use of diethylene glycol specified in D2694?
This specification strictly covers diethylene glycol for use in the preparation of surface coatings, including paints, varnishes, and lacquers. It is not intended for other industrial applications without further validation.
💡 What are the specific purity requirements for other glycols?
ASTM D2694 limits the concentration of other glycols to ensure high purity. The material must contain no more than 0.5 wt% ethylene glycol, and no more than 1.0 wt% triethylene glycol.
⚡ How is the color of the diethylene glycol determined?
Color can be evaluated using Test Method D1209 (visual Platinum-Cobalt scale) or Test Method D5386 (instrumental tristimulus colorimetry). The maximum acceptable color is 15 Pt-Co units.
📌 What packaging and sampling standards are referenced?
Sampling must follow Practice E300. Packaging of the final product must comply with U.S. Federal Specification PPP-C-2020, which covers the packaging of liquid, dry, and paste chemicals.