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Send EmailTriethylene Glycol, Triethyleneglycol, Triglycol, TEG, 112-27-6
TRIETHYLENE GLYCOL (TEG)
Triethylene Glycol / 2,2'-(Ethylenedioxy)diethanol / Triglycol / TEG
CAS Number: 112-27-6
EC Number: 203-953-2
| Parameter | Information |
|---|---|
| Product Name | Triethylene Glycol |
| Abbreviation | TEG |
| Chemical Name (IUPAC) | 2,2'-(Ethylenedioxy)diethanol |
| Other Names | Triglycol, Ethylene glycol bis(2-hydroxyethyl ether), 3,6-Dioxaoctane-1,8-diol, 1,2-Bis(2-hydroxyethoxy)ethane |
| CAS Number | 112-27-6 |
| EC Number (EINECS) | 203-953-2 |
| Molecular Formula | C₆H₁₄O₄ / HO–CH₂–CH₂–O–CH₂–CH₂–O–CH₂–CH₂–OH |
| Molecular Weight | 150.17 g/mol |
| Chemical Class | Glycol ether (diol) |
| Appearance | Colorless, clear, viscous liquid |
| Odor | Slight characteristic, almost odorless |
| Physical State (20°C) | Liquid |
Triethylene Glycol is a colorless, hygroscopic, viscous liquid belonging to the glycol ether family. It is produced as a by-product of ethylene oxide hydration or by the reaction of ethylene glycol with ethylene oxide. It is widely used as a dehydrating agent for natural gas, as a component in hydraulic brake fluids, as a plasticizer, and as a solvent in various industrial applications. Its low volatility, high boiling point, and excellent hygroscopic properties make it valuable in many sectors.
| Type | Name |
|---|---|
| Common Names | Triethylene Glycol, TEG, Triglycol |
| Chemical Names | 2,2'-(Ethylenedioxy)diethanol, Ethylene glycol bis(2-hydroxyethyl ether), 3,6-Dioxaoctane-1,8-diol, 1,2-Bis(2-hydroxyethoxy)ethane |
| CAS Number | 112-27-6 |
| EC Number | 203-953-2 |
| HS Code | 2909.49 |
| RTECS | YE4550000 |
Triethylene Glycol consists of three ethylene glycol units linked by two ether bonds, with two terminal hydroxyl groups.
Structural Formula:
HO – CH₂ – CH₂ – O – CH₂ – CH₂ – O – CH₂ – CH₂ – OH
Simplified Representation:
HO-(CH₂-CH₂-O)₃-H
C₆H₁₄O₄
150.17 g/mol
| Feature | Description |
|---|---|
| Functional Groups | Two hydroxyl (-OH) groups, two ether (-O-) groups |
| Chain Length | Three ethylene glycol units |
| Hydrogen Bonding | Strong (due to two hydroxyl groups) |
| Hygroscopicity | High (absorbs moisture from air) |
| Solubility | Miscible with water and many organic solvents |
| Hydrophilicity | High (log P ow = -1.75) |
| Property | Value / Range |
|---|---|
| Appearance (20°C) | Colorless, clear, viscous liquid |
| Odor | Slight characteristic, almost odorless |
| Molecular Formula | C₆H₁₄O₄ |
| Molecular Weight | 150.17 g/mol |
| Density (20°C) | 1.124 – 1.126 g/cm³ |
| Freezing Point | -4.3 to -7.2 °C (pure) |
| Boiling Point (1013 hPa) | 285-288 °C (some sources 276-288) |
| Flash Point (Closed Cup) | 166 °C (PMCC) – 177 °C (Cleveland) |
| Autoignition Temperature | 371 °C |
| Vapor Pressure (20°C) | <0.01 hPa |
| Viscosity (20°C) | ~47 mPa·s (cP) |
| Viscosity (25°C) | ~36 mPa·s |
| pH (50% in water) | 5.5 – 7.5 (neutral) |
| Water Solubility | Completely miscible |
| Solubility in Alcohols | Completely miscible |
| Solubility in Ketones | Completely miscible |
| Solubility in Hydrocarbons | Insoluble |
| Partition Coefficient (log P ow) | -1.75 (hydrophilic) |
| Thermal Decomposition | Slow oxidation >220°C; acidic products form >250°C |
| Specific Heat Capacity (20°C) | ~2.2 kJ/(kg·K) |
| Heat of Vaporization (at bp) | ~450 kJ/kg |
| Thermal Conductivity (20°C) | ~0.21 W/(m·K) |
| Dielectric Constant (20°C, 1 kHz) | ~23 |
| Hygroscopicity | High (absorbs moisture from air) |
| Solvent | Solubility | Conditions |
|---|---|---|
| Water | Completely miscible | All proportions |
| Ethanol | Completely miscible | All proportions |
| Methanol | Completely miscible | All proportions |
| Acetone | Completely miscible | All proportions |
| Chloroform | Completely miscible | All proportions |
| Benzene | Insoluble | 20°C |
| Toluene | Insoluble | 20°C |
| Hexane | Insoluble | 20°C |
| Ether | Partially soluble | 20°C |
| Property | Description |
|---|---|
| Chemical Character | Weakly acidic (due to hydroxyl groups) |
| Stability | Stable under normal storage conditions |
| Hygroscopicity | Absorbs moisture from air; store in sealed containers |
| Reaction with Acids | Forms esters (glycol esters) |
| Reaction with Isocyanates | Forms polyurethanes |
| Reaction with Borates | Forms borate esters (used in brake fluids) |
| Oxidation | Slow oxidation at high temperatures (>220°C) |
| Incompatible Materials | Strong oxidizers (HNO₃, H₂O₂), concentrated acids (H₂SO₄) – violent exothermic reaction |
| Test | Typical Value | Method |
|---|---|---|
| Purity (% weight) | ≥99.0 – 99.8 | GC |
| Water Content (Karl Fischer) | ≤0.1% | ASTM E203 |
| Color (APHA/Pt-Co) | ≤20 | ASTM D1209 |
| Acidity (as Acetic Acid) | ≤0.01% | ASTM D1613 |
| Ethylene Glycol + DEG | ≤0.5% | GC |
| Iron Content | ≤1 ppm | ICP |
| Ash Content | ≤0.01% | ASTM D482 |
| Density (20°C) | 1.124 – 1.126 g/cm³ | ASTM D4052 |
| Refractive Index (n20/D) | 1.455 – 1.456 | ASTM D1218 |
TEG + H₃BO₃ → TEG Borate Ester + H₂O
TEG + 2 R-NCO → Polyurethane + CO₂
TEG + R-COOH → TEG Ester + H₂O
TEG + [O] → Degradation Products + H₂O
Triethylene Glycol is produced as a by-product of ethylene oxide hydration or by the reaction of ethylene glycol with ethylene oxide.
| Stage | Process | Description |
|---|---|---|
| 1 | Ethylene Oxide Hydration | Ethylene oxide is hydrated with water under high pressure and temperature to produce MEG, DEG, TEG, and higher glycols. |
| 2 | Separation | The reaction mixture is separated by fractional distillation. |
| 3 | Purification | TEG is purified to meet technical or pharmaceutical grade specifications. |
| 4 | Stabilization | Antioxidants may be added to prevent degradation during storage. |
| Application | Description |
|---|---|
| Gas Dehydration | Liquid TEG absorbs water vapor from natural gas streams. |
| Glycol Circulation Rate | 15-30 L TEG / kg water removed |
| Contact Temperature | 25-40°C (absorption) |
| Regeneration Temperature | 180-204°C (atmospheric) |
| Vacuum Regeneration | 150-160°C (under vacuum) |
| TEG Purity (Regenerated) | 98.5 – 99.9% |
| Dew Point Depression | Down to -40°C |
| Application | Description |
|---|---|
| Brake Fluid Component | Provides low volatility and high boiling point |
| DOT 3 / DOT 4 Compatibility | TEG borate esters are key components |
| Dry Boiling Point | >260°C (DOT 4: >230°C) |
| Application | Description |
|---|---|
| Plasticizer | Used in cellulosic films, printing inks, polyurethane elastomers |
| Polyurethane Elastomers | Provides flexibility and elasticity |
| Polyester Resins | Modifier |
| Application | Description |
|---|---|
| Coalescent Aid | Improves film formation in water-based paints |
| Solvent | Auxiliary solvent in coatings |
| MFFT Reduction | Lowers minimum film formation temperature |
| Application | Description |
|---|---|
| Closed-Loop Systems | Heat transfer fluid |
| Operating Temperature | -10°C to +150°C (pressurized) |
| Typical Concentration | 30-50% TEG in water |
| Application | Description |
|---|---|
| Printing Inks | Flexibility enhancer, drying time regulator |
| Cosmetics | Humectant, solvent, viscosity regulator |
| Pharmaceuticals | Excipient (plasticizer, humectant, solvent) |
| Textiles | Softener, antistatic agent, humectant |
| Aviation | Low-temperature hydraulic fluids |
| Parameter | Value |
|---|---|
| TEG Circulation Rate | 15-30 L TEG / kg water removed |
| Contact Temperature | 25-40°C (absorption) |
| Regeneration Temperature | 180-204°C (atmospheric) |
| Vacuum Regeneration | 150-160°C (under vacuum) |
| TEG Purity (Regenerated) | 98.5 – 99.9% |
| Dew Point Depression | Down to -40°C |
Note: Oxygen must be excluded from TEG (prevents degradation and acid formation). pH should be maintained at 6-8.
| Component | % Weight |
|---|---|
| TEG | 50 – 70 |
| Boric Acid (H₃BO₃) | 15 – 25 |
| Diethylene Glycol (DEG) | 5 – 15 |
| Antioxidant (BHT, etc.) | 0.1 – 0.5 |
| Corrosion Inhibitor | 0.2 – 1.0 |
Process: TEG + Boric acid → esterification at 120-150°C (water removed) → cooling → add other components.
Target: Dry boiling point >260°C (DOT 4: >230°C).
| Component | % Weight |
|---|---|
| Acrylic Emulsion (50% solids) | 70 – 80 |
| TEG | 2 – 5 |
| Water | 10 – 20 |
| Surfactant | 0.5 – 1 |
| Defoamer | 0.2 – 0.5 |
Effect: Lowers Minimum Film Formation Temperature (MFFT). TEG acts as a temporary plasticizer after water evaporation.
| Component | % Weight |
|---|---|
| Water | 70 – 85 |
| TEG | 2 – 5 |
| Glycerin | 2 – 5 |
| Emulsifier (Polysorbate, etc.) | 1 – 3 |
| Preservative (Phenoxyethanol) | 0.5 – 1 |
| Fragrance | 0.1 – 0.3 |
Note: For cosmetic use, pharmaceutical/cosmetic grade TEG is required (heavy metals and DEG <0.1%).
| Component | % Volume |
|---|---|
| TEG | 30 – 50 |
| Water | 50 – 70 |
| Corrosion Inhibitor (Nitrite, Molybdate) | 0.5 – 2 |
| pH Regulator (Borax) | pH 8.5 – 10.5 |
Operating Temperature: -10°C (freeze protection) to +150°C (pressurized system).
| Sector | Suitability / Standards | Description |
|---|---|---|
| Natural Gas | GPSA, ISO 18453, NACE | Gold standard for dehydration (water removal). Absorbs water from gas streams with low vapor pressure. |
| Automotive (Brake Fluid) | FMVSS 116 (DOT 3, DOT 4), ISO 4925 | TEG is used as borate ester in brake fluids. Provides high boiling point. |
| Pharmaceutical | USP/NF (USP Monograph), Ph. Eur. | Excipient (plasticizer, humectant, solvent). Used in oral, topical, and injectable formulations. |
| Cosmetics | EC 1223/2009, CIR approved | Humectant, solvent, viscosity regulator. Used in shampoos, lotions, deodorants, creams. |
| Paints & Coatings | REACH, EPA TSCA | Coalescent auxiliary solvent; improves film formation in water-based paints. |
| Printing Inks | EC 1935/2004 (if not food contact) | Enhances flexibility, regulates drying time. |
| Heat Transfer | ASTM E1177 (coolants) | Closed-loop heat transfer fluid, antifreeze additive. |
| Plastics & Polyurethane | RoHS compliant | Plasticizer; provides flexibility in polyurethane elastomers. |
| Textiles | OEKO-TEX (limited concentration) | Softener, antistatic agent, humectant. |
| Aviation | MIL-PRF-46170 (hydraulic fluids) | Low-temperature fluidity and high-temperature stability. |
Food Contact Applications:
TEG is covered under FDA 21 CFR 178.3740 (indirect food contact – extractable substances in plastics) but is generally NOT APPROVED as a direct food additive (like EG and DEG). Limited use as a heat transfer fluid in food processing equipment.
| Material | Compatibility | Notes |
|---|---|---|
| Stainless Steel (304, 316) | Excellent | Recommended |
| Carbon Steel | Good | Suitable |
| Aluminum | Good | Suitable |
| Polyethylene (HDPE) | Excellent | Recommended for storage |
| Polypropylene (PP) | Excellent | Recommended |
| Copper | Limited | Not recommended for long-term contact (discoloration) |
| Brass | Limited | Not recommended for long-term contact |
| EPDM Seals | Limited | May swell – use Viton® or PTFE |
| Parameter | Information |
|---|---|
| Storage Temperature | 15-40°C (protect from freezing; crystallization begins below -5°C) |
| Container Requirements | Stainless steel, carbon steel, HDPE drums/tanks. Store under dry air or nitrogen to prevent moisture absorption. |
| Materials to Avoid | Strong oxidizers, concentrated acids |
| Shelf Life | 24 months (in unopened original packaging, below 25°C, protected from direct sunlight) |
| Signs of Degradation | Color change (darkening), acidity increase |
| Packaging Type | Quantity | Material |
|---|---|---|
| Steel Drum | 200-250 kg | Carbon steel / Stainless steel |
| IBC Tank | 1100-1250 kg | HDPE / Stainless steel |
| Bulk Tanker | 20-23 tons | Stainless steel / Carbon steel |
| Parameter | Information |
|---|---|
| UN Number | Not applicable (not classified as dangerous goods) |
| Hazard Class | Not classified as hazardous for transport |
| Packing Group | Not applicable |
| ADR/RID | Not regulated |
| IMDG Code | Not regulated |
| IATA (Air) | Not regulated |
| Marine Pollutant | No |
| Transport Temperature | Ambient temperature; protect from freezing and moisture. |
| Parameter | Value |
|---|---|
| Acute Oral Toxicity (LD50, Rat) | ~15-17 g/kg (low toxicity) |
| Acute Dermal Toxicity (LD50, Rabbit) | > 20,000 mg/kg |
| Skin Irritation | Mild irritant; prolonged exposure may cause dryness and cracking |
| Eye Irritation | Mild to moderate irritant |
| Inhalation | Low risk (low vapor pressure); aerosol may cause respiratory irritation |
| Mutagenicity | Negative |
| Carcinogenicity | Not classified (IARC Group 4 – probably not carcinogenic) |
| Reproductive Toxicity | Not classified |
| Target Organs | No specific target organs identified |
| Parameter | Value |
|---|---|
| TWA (8 hours) | 10 mg/m³ (aerosol) |
| STEL (15 min) | Not established |
GHS Classification (Not Classified as Hazardous in Most Jurisdictions):
| Hazard Class | Category | H-Statement |
|---|---|---|
| Not classified as hazardous | - | - |
Signal Word: None (not classified as hazardous)
Hazard Pictograms: None
Hazard Statements (H-Codes): None (in some regions, H316 and H320 may be requested)
| Code | Statement |
|---|---|
| P264 | Wash hands thoroughly after handling. |
| P280 | Wear protective gloves/protective clothing/eye protection/face protection. |
| P302+P352 | IF ON SKIN: Wash with plenty of soap and water. |
| P305+P351+P338 | IF IN EYES: Rinse cautiously with water for several minutes. Remove contact lenses if present. |
| P501 | Dispose of contents/container in accordance with local regulations. |
| Route of Exposure | Action to Be Taken |
|---|---|
| Inhalation | Move to fresh air. If respiratory irritation persists, seek medical attention. |
| Skin Contact | Wash with plenty of soap and water. Remove contaminated clothing. If irritation persists, consult a physician. |
| Eye Contact | Rinse thoroughly with plenty of water for at least 15 minutes. Remove contact lenses. If irritation persists, seek medical attention. |
| Ingestion | Rinse mouth with water. Drink plenty of water. Do not induce vomiting. If large amount is swallowed, seek medical attention. |
| Parameter | Information |
|---|---|
| Fire Hazard | Combustible liquid (Flash point >166°C). |
| Suitable Extinguishing Media | Water spray, CO₂, dry chemical powder, alcohol-resistant foam. |
| Special Hazards | Thermal decomposition produces toxic fumes including carbon monoxide and carbon dioxide. |
| Protective Equipment | Self-contained breathing apparatus (SCBA), full protective clothing. |
| Parameter | Information |
|---|---|
| Personal Protection | Protective goggles, chemical-resistant gloves, coverall. |
| Ventilation | Increase ventilation; use local exhaust in confined spaces. |
| Containment | Absorb with inert material (sand, vermiculite). |
| Cleaning Methods | Collect with absorbent material. Avoid washing with water (spread). |
| Environmental Precautions | Prevent entry into drains, sewers, and water bodies. |
| Waste Disposal | Dispose of in accordance with local regulations. |
| Parameter | Information |
|---|---|
| Aquatic Toxicity | Low toxicity to aquatic organisms. |
| Biodegradability | Readily biodegradable (OECD 301). |
| Bioaccumulation | Low potential (log P ow = -1.75). |
| Water Hazard Class (WGK Germany) | 1 (low hazard to water). |
| Waste Disposal | Incineration (with energy recovery) or controlled discharge to wastewater treatment (EWC code: 07 02 99). |
| Region / Authority | Status |
|---|---|
| European Union (REACH) | Registered; industrial chemical. |
| USA (TSCA) | Listed. |
| Turkey (KKDIK) | Registration required (post-2023, sector-dependent). |
| Australia (AICS) | Listed. |
| FDA | 21 CFR 178.3740 (indirect food contact). |
| GHS (EU 1272/2008) | Not classified as hazardous. |
| Application | Alternative | Advantages / Disadvantages |
|---|---|---|
| Natural Gas Dehydration | DEG | Lower viscosity, lower boiling point, higher vapor loss. TEG offers higher thermal stability. |
| MEG | Lower cost but much more volatile; large losses. Preferred in cold climates (hydrate inhibitor). | |
| Ionic Liquids | Very low vapor pressure, high selectivity, but very high cost; not yet widespread. | |
| Brake Fluid | DEG + Borate Ester | Lower viscosity, lower boiling point. TEG offers higher performance (DOT 4). |
| PEG 200-400 | Higher viscosity, better lubrication. More expensive than TEG. | |
| Plasticizer (Water-based) | Propylene Glycol (PG) | Lower toxicity, food contact suitable, but higher cost. |
| Dipropylene Glycol (DPG) | Lower hygroscopicity; preferred in some coatings. | |
| Texanol™ | Very effective coalescent, lower water solubility, but may have VOC restrictions. | |
| Heat Transfer Fluid | Propylene Glycol (PG) | Less toxic, preferred in food processing. More expensive than TEG; similar low-temperature performance. |
| Ethylene Glycol (EG) | Lowest cost, best heat transfer, but high toxicity. | |
| Cosmetics / Pharma | Propylene Glycol (PG) | Lower skin irritation potential, more widely accepted. |
| Glycerin | Natural source, higher viscosity, sweeter taste. | |
| Butylene Glycol | Lighter feel, more expensive. | |
| Paints / Inks | DPG | Less hygroscopic, better water resistance. |
| PG | Lower toxicity, but higher volatility. |
| Name | Context |
|---|---|
| Triethylene Glycol | IUPAC name |
| TEG | Most common abbreviation |
| Triglycol | Common trade name |
| 2,2'-(Ethylenedioxy)diethanol | Chemical name |
| Ethylene glycol bis(2-hydroxyethyl ether) | Chemical name |
| 3,6-Dioxaoctane-1,8-diol | Systematic name |
| 1,2-Bis(2-hydroxyethoxy)ethane | Chemical name |
| Triethyleneglycol | Combined spelling |
| Property | Value |
|---|---|
| CAS Number | 112-27-6 |
| EC Number | 203-953-2 |
| Molecular Formula | C₆H₁₄O₄ |
| Molecular Weight | 150.17 g/mol |
| Appearance | Colorless, clear, viscous liquid |
| Odor | Almost odorless |
| Density (20°C) | 1.124 – 1.126 g/cm³ |
| Boiling Point | 285-288 °C |
| Flash Point | 166-177 °C |
| Viscosity (20°C) | ~47 mPa·s |
| Water Solubility | Completely miscible |
| pH (50% solution) | 5.5 – 7.5 |
| Primary Uses | Natural gas dehydration, brake fluids, plasticizer, heat transfer fluids |
| Shelf Life | 24 months |
| UN Number | Not applicable |
| GHS Signal Word | None |
CRITICAL NOTICES:
Hygroscopic Nature: TEG is highly hygroscopic and absorbs moisture from the air. Store in sealed containers under dry air or nitrogen to maintain purity.
Freezing Point: TEG begins to crystallize below -5°C. Protect from freezing to prevent tank damage. Use heated storage (15-40°C) in cold climates.
Temperature Limit: Do not exceed 220°C in air. Above this temperature, slow oxidation occurs, forming acids (pH drops, corrosion increases). Use inert gas (N₂) in regeneration units.
Incompatibility: Incompatible with strong oxidizers (HNO₃, H₂O₂) and concentrated acids (H₂SO₄) – violent exothermic reaction.
pH Monitoring: In TEG circuits, maintain pH between 6-8. If pH <5, neutralize (with monoethanolamine) or replace the TEG.
Food Contact: TEG is not approved as a direct food additive. Only limited use as a heat transfer fluid in food processing equipment. Use Propylene Glycol for food contact applications.
Brake Fluid: For automotive brake fluids, use high-purity TEG with low DEG and EG content. Impurities can affect boiling point and performance.
Material Compatibility: Use stainless steel, carbon steel, or HDPE. Avoid copper and brass for long-term contact (discoloration). Use Viton® or PTFE seals (EPDM may swell).
BEST PRACTICE RECOMMENDATIONS:
Storage: Store in a cool, dry, and well-ventilated area at 15-40°C. Keep containers tightly closed. Protect from moisture and direct sunlight. Use nitrogen blanket for large tanks.
Handling: Use protective gloves (nitrile), goggles, and appropriate clothing. Ensure adequate ventilation.
Transfer: Use sealed transfer systems. Use stainless steel or HDPE equipment.
Quality Control: Monitor purity, water content, pH, and color. Test for DEG and EG content (GC). Request CoA from supplier.
pH Control: In glycol circuits, maintain pH 6-8. Add corrosion inhibitors as needed.
Filtration: In gas dehydration applications, filter TEG through activated carbon to remove accumulated contaminants (H₂S, CO₂, hydrocarbons).
Waste Management: Dispose of waste in accordance with local regulations. Incineration with energy recovery is recommended.
LEGAL DISCLAIMER:
This Technical Data Sheet (TDS) is for informational purposes only and is prepared based on available technical data. The user is solely responsible for determining the suitability of the product for their specific application and for complying with all local, national, and international regulations. For complete safety, storage, handling, transport, waste, and regulatory compliance information, the official Safety Data Sheet (SDS/MSDS) provided by the manufacturer/supplier must be consulted. This document does not substitute professional advice.