What Is 2-Methyl-2,4-Pentanediol?
Uses, Properties & Industry Overview
A complete guide to hexylene glycol (CAS 107-41-5) - from molecular structure and physical properties to industrial applications, safety essentials, and global sourcing.
📋 Table of Contents
1 ⚗️ What Is 2-Methyl-2,4-Pentanediol?
2-Methyl-2,4-pentanediol - abbreviated as MPD and commercially known as hexylene glycol - is a short-chain branched diol belonging to the aliphatic glycol family. Its IUPAC name fully describes its structure: a six-carbon (hexyl) backbone with two hydroxyl (–OH) groups positioned at carbons 2 and 4, and a methyl branch at carbon 2.
This compound was first commercialized in the mid-20th century as a specialty solvent, and today it serves a remarkably wide range of industries. From cosmetic preservative boosters and skin-conditioning humectants to industrial coatings coalescents and hydraulic fluid additives, MPD's dual functionality - combining solvent power with surface-active behaviour - makes it a uniquely versatile ingredient.
💡 Quick Identity Snapshot
Common name: Hexylene Glycol | Abbreviation: MPD | CAS No.: 107-41-5 | EINECS: 203-489-0
Molecular formula: C₆H₁₄O₂ | Molecular weight: 118.17 g/mol
The compound is miscible with water and most common organic solvents, a property that underpins its role as a coupling agent - bridging the gap between polar aqueous phases and non-polar oil phases in formulations. This characteristic, combined with its relatively low volatility and mild odour, makes it a formulator's first choice when a balanced, multi-functional glycol solvent is needed.
2 🔬 Molecular Structure & Chemical Identity
Understanding MPD's structure is the key to understanding its behaviour. The branched carbon skeleton - rather than a straight chain - provides steric shielding around the hydroxyl groups, which moderates their reactivity and lowers the compound's affinity for hydrogen-bond networking compared to straight-chain diols of similar molecular weight. The result is a liquid that is less viscous, less hygroscopic, and more compatible with a wider range of organic matrices than, say, 1,6-hexanediol.
| Identifier | Value | Notes |
|---|---|---|
| IUPAC Name | 2-methylpentane-2,4-diol | Systematic name per IUPAC 2013 recommendations |
| CAS Registry No. | 107-41-5 | Unique chemical identifier - see PubChem CID 11593 |
| Molecular Formula | C₆H₁₄O₂ | Two –OH groups, six carbons, branched |
| Molecular Weight | 118.17 g/mol | |
| InChI Key | FRJJJAKBRKUSLL-UHFFFAOYSA-N | Standard InChI identifier |
| SMILES | CC(O)CC(C)(C)O | Canonical SMILES notation |
| EINECS No. | 203-489-0 | EU inventory - ECHA substance page |
| Chiral centres | 1 (carbon-4) | Commercial product is a racemate (R + S mixture) |
For a detailed interactive 3D structure, visit PubChem's 3D Conformer page for CID 11593. The branching at C-2 (tertiary alcohol) vs. the secondary alcohol at C-4 means the two –OH groups have different reactivities, a subtlety that matters in esterification and polymer synthesis applications.
For a deeper technical discussion of the structure, stereochemistry, and condensed structural formula of MPD, see our companion article: Chemical Structure of 2-Methyl-2,4-Pentanediol: Molecular Formula, Bonds & Stereochemistry →
3 📊 Key Physical & Chemical Properties
MPD is a colourless, slightly oily liquid at room temperature with a mild, characteristic odour. Its physical properties sit in a useful "sweet spot" - appreciable boiling point for low-volatility handling, full water miscibility for aqueous system compatibility, and moderate viscosity for easy processing.
| Property | Value | Significance |
|---|---|---|
| Appearance | Colourless to pale yellow liquid | Easy visual QC check |
| Boiling Point | 197–198 °C (1 atm) | Low volatility - safe for hot-process formulations |
| Melting Point | −50 °C | Liquid across all storage temperatures |
| Density (20 °C) | 0.921 g/cm³ | Slightly lighter than water |
| Viscosity (25 °C) | ~36 mPa·s | Pumpable; moderate thickening effect |
| Flash Point | 88 °C (closed cup) | Combustible but not flammable at room temperature |
| Water Miscibility | Completely miscible | Key advantage for aqueous formulations |
| LogP (octanol/water) | 0.58 | Balanced hydrophilicity / lipophilicity |
| Refractive Index (nD 20) | 1.4225 | Useful purity indicator |
| Vapour Pressure (20 °C) | <0.1 hPa | Negligible inhalation risk under normal conditions |
📌 Data contextualised from NIST WebBook (CAS 107-41-5) and supplier technical datasheets. For the full specification sheet and Certificate of Analysis, visit our product page →
The notably low vapour pressure is a practical advantage in industrial settings: workers handling MPD in open systems face minimal inhalation exposure under ambient conditions, unlike lower-molecular-weight glycol ethers. Read more on the boiling point profile and thermodynamic data in our article: Boiling Point, Vapor Pressure & Key Physical Properties of 2-Methyl-2,4-Pentanediol →
4 🏭 Major Industrial Applications
MPD's combination of high solvency, low volatility, water miscibility, and mild toxicity profile has secured it a place in a broad spectrum of industrial end uses.
🎨 Paints & Coatings
Acts as a coalescent and flow agent in waterborne latex paints, reducing minimum film formation temperature (MFFT) and improving surface levelling without the regulatory concerns of more volatile solvents.
🖨️ Printing Inks
Used in water-based flexographic and gravure inks as a retarder and coupling solvent, improving open time and reducing print defects on demanding substrates.
⚙️ Hydraulic Fluids
Serves as a viscosity modifier and anti-freeze component in fire-resistant hydraulic fluids, particularly in water-glycol types used in steel mills and die-casting operations.
🧹 Industrial Cleaners
Functions as a coupling agent in hard-surface cleaners and degreasers, solubilising surfactant and oil phases into stable, clear aqueous solutions.
🏗️ Construction Chemicals
Applied as a plasticiser auxiliary in cementitious formulations, improving workability and open time of reactive polymer systems.
🧪 Chemical Synthesis
A building block in the production of specialty polyesters, polyurethane intermediates, and as a ligand precursor in organometallic catalysis (the MPD ligand in Ziegler-Natta systems).
For a comprehensive technical deep-dive into industrial solvent applications, see: Hexylene Glycol as an Industrial Solvent: Coatings, Inks & Hydraulic Fluids →
5 🌸 Personal Care & Cosmetic Uses
Hexylene glycol holds an established position in personal care formulation, approved and listed in both the EU CosIng database and the PCPC International Cosmetic Ingredient Dictionary under the INCI name HEXYLENE GLYCOL. It performs multiple functions simultaneously within a single ingredient, a key economic advantage in modern formulation.
✅ Five Roles of Hexylene Glycol in Cosmetics
🔹 Solvent - dissolves and stabilises active ingredients, fragrances, and preservatives in aqueous formulations
🔹 Humectant - attracts and retains moisture in the upper layers of the skin
🔹 Viscosity reducer - thins over-viscous emulsions and serums for better spreadability
🔹 Preservative booster - enhances the efficacy of phenoxyethanol, parabens, and organic acid preservative systems by disrupting microbial cell membranes
🔹 Emollient auxiliary - imparts a light, non-greasy skin feel at typical use concentrations (1–5%)
Typical use concentrations in finished cosmetics range from 0.5% to 5% w/w, with the preservative-booster effect most pronounced in the 1–3% range when paired with optimised preservative blends. The ingredient is considered safe for use in rinse-off and leave-on products at these concentrations by the Cosmetic Ingredient Review (CIR) Expert Panel.
Explore the full formulation landscape in: 2-Methyl-2,4-Pentanediol in Personal Care: Solvent, Humectant & Preservative Booster →
6 ⚖️ How MPD Compares to Related Glycols
Formulators often evaluate MPD against neighbouring diol solvents. The table below provides a quick comparison of the most commonly considered alternatives.
| Property | MPD (Hexylene Glycol) | Propylene Glycol | 1,6-Hexanediol | TMPD |
|---|---|---|---|---|
| CAS No. | 107-41-5 | 57-55-6 | 629-11-8 | 144-19-4 |
| Boiling Point | 197–198 °C | 188 °C | 250 °C | 235 °C |
| Water Miscibility | ✅ Complete | ✅ Complete | ⚠️ Limited | ⚠️ Limited |
| Preservative Boosting | ✅ Strong | ⚠️ Mild | ❌ None | ❌ None |
| Flash Point | 88 °C | 99 °C | 102 °C | 113 °C |
| Typical Use: Coatings | ✅ Coalescent | ⚠️ Co-solvent | ✅ Chain extender | ✅ Polyol |
For a full head-to-head analysis, see: 2-Methyl-2,4-Pentanediol vs Other Glycol Solvents → and Trimethyl Pentanediol vs Hexylene Glycol →
7 🛡️ Safety & Regulatory Overview
MPD has a well-characterised safety profile established through decades of industrial use and formal regulatory review. The key data points for risk assessment are summarised below.
⚠️ GHS Hazard Classification (CLP / GHS)
🔸 Eye Irritation Cat. 2 - causes eye irritation (H319)
🔸 Skin Irritation Cat. 3 - may cause mild skin irritation (H316)
🔸 Combustible liquid - flash point 88 °C (H227)
Classification per ECHA C&L Inventory. Not classified as CMR, PBT, or vPvB under current EU assessment.
Key safe-handling points:
✅ Storage: Store in tightly closed containers in a cool, dry, well-ventilated area away from ignition sources. Recommended temperature: 5–35 °C. Compatible with stainless steel, HDPE, and glass.
✅ PPE: Safety goggles and chemical-resistant gloves (nitrile recommended) for regular handling. Full-face shield for bulk transfer.
✅ Spill response: Absorb with inert material (sand, vermiculite). Dispose as per local regulations - consult your SDS.
✅ Regulatory status: Listed on EU REACH, US TSCA, China IECSC, Korean ECL, and Japanese ENCS inventories - globally tradeable without special restrictions.
For complete GHS labelling, first-aid measures, storage compatibility tables, and waste disposal guidance, see: 2-Methyl-2,4-Pentanediol Safety: SDS, Handling, Storage & Regulatory Compliance →
To download the official Safety Data Sheet (SDS) for our product, visit the product page →
8 🌍 Global Market & Sourcing
The global hexylene glycol market is served by a relatively concentrated group of producers, with major capacity located in China, the United States, and Germany. China has emerged as the dominant export hub, accounting for a substantial share of Asia-Pacific trade volumes, with product shipped in 200 kg drums, 1,000 kg IBC totes, and ISO tank containers for bulk orders.
Demand growth is driven by the continued expansion of waterborne coatings (replacing solvent-borne formulations under VOC regulations), growing personal care markets in Asia, and the increasing adoption of fire-resistant hydraulic fluids in heavy industry. Market analysts at ICIS track hexylene glycol pricing as part of the broader glycol solvent basket.
🏭 Why Source from China?
✅ Competitive ex-works pricing vs. European and US producers
✅ Flexible MOQ - from 1 drum (200 kg) to full container loads
✅ Multiple purity grades: industrial (>98%), cosmetic (>99.5%)
✅ COA, MSDS, REACH documentation provided with every shipment
✅ Export experience to 50+ countries across EU, SEA, Middle East, and Americas
For a complete buyer's guide covering Incoterms, HS codes, lead times, and quality verification, see: How to Source 2-Methyl-2,4-Pentanediol: Supplier Guide, Packaging & Export from China →
9 ❓ Frequently Asked Questions
Q: Is hexylene glycol the same as 2-methyl-2,4-pentanediol?
A: Yes - hexylene glycol is the most common commercial trade name for 2-methyl-2,4-pentanediol. Other synonyms include MPD, 2-methyl pentane-2,4-diol, and diolane. All refer to the same compound with CAS 107-41-5.
Q: What is the difference between hexylene glycol and propylene glycol?
A: Both are water-miscible diols, but hexylene glycol (6-carbon, branched) has a higher boiling point, lower volatility, and significantly stronger preservative-boosting activity than propylene glycol (3-carbon). Propylene glycol is food-grade approved and used at much higher concentrations; MPD is typically used at 0.5–5% as a functional additive.
Q: Is 2-methyl-2,4-pentanediol safe for cosmetic use?
A: Yes, at approved concentrations. It is listed in the EU CosIng database as a permitted cosmetic ingredient. The CIR Expert Panel has concluded that hexylene glycol is safe as a cosmetic ingredient at concentrations up to 5% in leave-on products and higher in rinse-off formulations.
Q: What purity grades of hexylene glycol are available?
A: Industrial grade (≥98.0% purity) for coatings, hydraulic fluids, and cleaners; cosmetic / pharmaceutical grade (≥99.5% purity) for personal care and sensitive applications. Both grades are available from Sinolook Chemical with COA provided. Request specifications on our product page →
Q: What is the HS code for importing hexylene glycol?
A: The most common HS classification is 2905.19 (acyclic diols not elsewhere specified) or 2905.49 depending on the importing country's tariff schedule. Our export team can provide the exact HS code for your jurisdiction upon request.
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