Diethylene Glycol Monoethyl Ether (111-90-0) Physical and Chemical Properties
Diethylene Glycol Monoethyl Ether
A polar, protic glycol ether used industrially as a solvent and processing aid, miscible with water and many organic solvents for formulation and synthesis applications.
| CAS Number | 111-90-0 |
| Family | Glycol ethers |
| Typical Form | Colorless liquid |
| Common Grades | BP, EP, JP, Reagent Grade, USP |
Diethylene glycol monoethyl ether is a glycol ether of the diethylene glycol family: a primary alcohol bearing an ethoxy–ethoxy substituent. Its stoichiometric composition is \(\ce{C6H14O3}\) and the molecule contains a terminal hydroxyl group and two ether linkages arranged as an ethoxy–ethylene–oxy–ethylene chain. Structurally it is classed as a hydroxypolyether (glycol ether), combining protic (hydroxyl) and aprotic (ether) functionality within a relatively small, flexible chain.
Electronically the molecule is moderately polar: multiple oxygen atoms give rise to significant hydrogen-bonding capacity (one hydrogen-bond donor and three acceptors by count), a topological polar surface area of 38.7 Å^2 and a low partition coefficient consistent with hydrophilicity. These features drive high miscibility with water and common polar organic solvents, relatively low volatility and limited bioconcentration. The protic OH confers reactivity typical of primary alcohols (esterification, oxidation under vigorous conditions), while the ether linkages are chemically stable to neutral aqueous media but susceptible to strong acids, strong oxidizers and peroxidation under certain conditions.
Industrial relevance arises from its role as a versatile solvent, humectant and co-solvent in coatings, textiles, photographic processing, personal-care and fragrance formulations, and as a diluent in brake fluids and hydraulic fluids. It is also used as an intermediate (e.g., in acrylate synthesis) and as an ingredient in some pesticide formulations where solvent properties are required. Common commercial grades reported for this substance include: BP, EP, JP, Reagent Grade, USP.
Basic Physical Properties
Density
Reported values for liquid density cluster near unity but slightly less than water. Representative experimental values include \(\;0.99\) (relative density, water = 1) and \(\;0.9885\ \mathrm{g/cu\ m}\) at 20 \(^\circ\)C (as reported). The material is described as slightly less dense than water and will tend to float on water surfaces in bulk spill situations.
Melting Point
Reported freezing/melting points vary with source and purity; values present in the data include \(-108\ ^\circ\mathrm{F}\) and a freezing point of \(-54.0\ ^\circ\mathrm{C}\). No single, universally adopted melting point is provided in the current data context.
Boiling Point
Several experimental boiling point values are reported: \(\;396\ ^\circ\mathrm{F}\) (reported at 760 mmHg / NTP, 1992) and \(\;196\ ^\circ\mathrm{C}\). A range entry of \(\;196\text{–}202\ ^\circ\mathrm{C}\) is also cited. These values reflect the low volatility and relatively high boiling temperature typical of small polyether alcohols.
Vapor Pressure
Measured vapor-pressure data include \(\;0.13\ \mathrm{mmHg}\) at 77 \(^\circ\mathrm{F}\) (NTP, 1992) and a value reported as \(\;0.12\ \mathrm{mmHg}\). A corresponding vapor pressure reported as 19 Pa at 25 \(^\circ\mathrm{C}\) is also listed. The low vapor pressure is consistent with the compound's limited volatility at ambient temperature.
Flash Point
Flash-point values reported include \(\;205\ ^\circ\mathrm{F}\) and \(\;196\ ^\circ\mathrm{F}\) (\(91\ ^\circ\mathrm{C}\), closed cup). A closed-cup flash point of \(\;96\ ^\circ\mathrm{C}\) is also cited. The substance is thus combustible under elevated-temperature conditions but not highly flammable at normal ambient temperatures.
Chemical Properties
Solubility and Phase Behavior
Diethylene glycol monoethyl ether is miscible with water at 25 \(^\circ\mathrm{C}\) and is described as “very soluble” or miscible with many common organic solvents (ethanol, acetone, benzene, ethyl ether, chloroform, pyridine). A solubility note lists “greater than or equal to 100 mg/mL at 68 \(^\circ\mathrm{F}\).” High hygroscopicity is reported; the compound mixes readily into aqueous and polar organic phases, making it an effective humectant and solvent for polar solutes.
Reactivity and Stability
The compound is generally stable under normal storage conditions but shows typical reactivity of alcohols and ethers: it can be oxidized under strong oxidizing conditions and can form unstable peroxides upon prolonged oxidation in air in some ether systems. It is incompatible with strong oxidizers and can react exothermically with strong acids (e.g., chlorosulfonic acid, oleum). Avoid mixing with powerful oxidizing agents, strong acids and perchloric acid conditions that can promote violent decomposition. When heated to decomposition it emits acrid smoke and irritating fumes.
Thermodynamic Data
Standard Enthalpies and Heat Capacity
No experimentally established standard enthalpies of formation or phase-change enthalpies are provided in the current data context. Reported heat-capacity–related data include a specific heat of \(\;2.31\ \mathrm{J\,g^{-1}\,K^{-1}}\), which can be used for thermal balance calculations in process systems where the material is heated or cooled.
Molecular Parameters
Molecular Weight and Formula
Molecular weight: \(\;134.17\) (as reported).
Molecular formula: \(\ce{C6H14O3}\).
LogP and Polarity
Reported partitioning and polarity descriptors include XLogP = \(-0.5\) and log Kow ≈ \(-0.54\). Topological polar surface area (TPSA) is reported as 38.7 Å^2. Combined with hydrogen-bond donor count = 1 and acceptor count = 3, these descriptors indicate a predominantly hydrophilic molecule with low tendency to bioaccumulate and good aqueous solubility.
Structural Features
The structure is best described as 2-(2-ethoxyethoxy)ethanol (IUPAC): a primary alcohol at one terminus with two ether oxygen atoms in the chain. The chain flexibility (6 rotatable bonds reported) and the presence of both hydrogen-bonding and ether oxygens underpin solvent properties that solubilize both polar solutes and moderate amounts of less polar organics, acting as a mutual solvent in many formulations.
Identifiers and Synonyms
Registry Numbers and Codes
- CAS number: 111-90-0
- EC number: 203-919-7
- UNII: A1A1I8X02B
- ChEBI: CHEBI:40572
- KEGG: D08904
SMILES: CCOCCOCCO
InChI: InChI=1S/C6H14O3/c1-2-8-5-6-9-4-3-7/h7H,2-6H2,1H3
InChIKey: XXJWXESWEXIICW-UHFFFAOYSA-N
Synonyms and Structural Names
Common synonyms and trade-style names appearing in available descriptions include: Diethylene glycol monoethyl ether; 2-(2-Ethoxyethoxy)ethanol; CARBITOL; Ethoxydiglycol; Ethyl carbitol; Transcutol; Ethyl diethylene glycol; Diethylene glycol ethyl ether; Ethoxy diglycol; DEGMEE; Ethyl digol. (These names reflect identical or closely related nomenclature used in industrial and formulation contexts.)
Industrial and Commercial Applications
Representative Uses and Industry Sectors
Diethylene glycol monoethyl ether is widely used as a solvent and co-solvent across multiple sectors: protective coatings, lacquers, varnishes and enamels (solvent for nitrocellulose and resins); textile printing and dyeing; photographic processing; formulation solvent in cosmetics and toiletries (humectant, solvent for fragrances and actives); as a diluent for hydraulic and brake fluids; and as an intermediate for chemical synthesis (e.g., acrylate derivatives). It appears in consumer and industrial products where moderate solvency, low volatility and humectant behavior are required.
Role in Synthesis or Formulations
Functionally the molecule acts as a protic, polar solvent that can dissolve polar resins, dyes and many small organic molecules while maintaining some compatibility with less polar oils. This makes it useful as a co-solvent or mutual solvent in complex formulations (e.g., mineral-oil–soap mixtures, coatings). It is also a synthetic building block for ether- and ester-based derivatives such as 2-(2-ethoxyethoxy)ethyl acrylate.
Safety and Handling Overview
Acute and Occupational Toxicity
Acute toxicity values reported vary by study and species; reported oral LD50 values in rats span entries such as 1920 mg/kg to 7500 mg/kg (multiple studies). Inhalation LC50 (rat) is reported as >5240 mg/m^3 over 4 hours. The chemical is a moderate eye irritant and can defat skin on repeated exposure, leading to dryness or cracking. Toxicokinetic data indicate urinary excretion of the primary metabolite (2‑ethoxyethoxyacetic acid) after oral dosing in humans (e.g., ~68–69% excreted within 12 hr in cited human observations).
Provisional toxicity reference values reported include: chronic oral Reference Dose (RfD) \(\;6\times10^{-2}\ \mathrm{mg\,kg^{-1}\,day^{-1}}\) and subchronic RfD \(\;6\times10^{-1}\ \mathrm{mg\,kg^{-1}\,day^{-1}}\); chronic inhalation Reference Concentration (RfC) \(\;3\times10^{-4}\ \mathrm{mg\,m^{-3}}\) and subchronic RfC \(\;3\times10^{-3}\ \mathrm{mg\,m^{-3}}\). These values should be used according to regulatory guidance for risk assessment and workplace control planning.
Occupational exposure limits reported include a WEEL 8‑hr TWA of 25 ppm and a German MAK of 50 mg/m^3 (inhalable fraction). Personnel working with the material should implement engineering controls and personal protective equipment (chemical-resistant gloves, goggles, protective clothing) to limit dermal and inhalational exposure, and use local exhaust ventilation for processes generating mists or aerosols.
Storage and Handling Considerations
Store in a cool, well-ventilated area away from strong oxidizers and strong acids. Containers should be grounded and bonded when transferring larger quantities to avoid static discharge; keep ignition sources away at elevated temperatures. The substance is hygroscopic and containers should be kept tightly closed. In bulk handling, provide liquid-impermeable gloves and splash goggles; for unknown atmospheres, use appropriate respiratory protection. For spills, collect liquid into sealable containers and rinse residuals with copious water, preventing discharge to sewers and watercourses where applicable.
For detailed hazard, transport and regulatory information, users should refer to the product-specific Safety Data Sheet (SDS) and local legislation.
