1-Methoxy-2-propanol (PGME): Properties, Uses & Safety FAQ

1-Methoxy-2-propanol（PGME） is a versatile glycol ether solvent widely used in semiconductor photolithography, coatings, and chemical synthesis due to its excellent solvating power, low toxicity profile relative to ethylene glycol ethers, and favorable evaporation rate.

Chemical Name

1-Methoxy-2-propanol (Propylene Glycol Methyl Ether, PGME)

CAS Number

107-98-2

Molecular Formula

C4H10O2

Molecular Weight

90.12 g/mol

Boiling Point

120 °C (at 760 mmHg)

Flash Point

32 °C (closed cup)

Appearance

Colorless, clear liquid with mild ethereal odor

What Is 1-Methoxy-2-propanol (PGME)?

1-Methoxy-2-propanol, commonly abbreviated as PGME (Propylene Glycol Methyl Ether), is a propylene glycol-based monoether solvent with the CAS number 107-98-2 and molecular formula C4H10O2 (MW 90.12 g/mol). It is a colorless, low-viscosity liquid with a mild ethereal odor that is miscible with water and most common organic solvents.

PGME belongs to the propylene glycol ether family, which is generally considered to have a more favorable toxicological profile than the analogous ethylene glycol ether series. The compound exists as a mixture of two isomers in commercial products, with 1-methoxy-2-propanol being the dominant isomer.

Key Physical and Chemical Properties

Understanding the physical and chemical properties of PGME is essential for selecting it as a solvent in research and industrial applications:

• Boiling Point: approximately 120 °C at 760 mmHg
• Flash Point: approximately 32 °C (closed cup), classifying it as a flammable liquid
• Density: approximately 0.919–0.922 g/mL at 25 °C
• Refractive Index: approximately 1.4030–1.4070 at 20 °C
• Miscibility: fully miscible with water, ethanol, acetone, and most aromatic and aliphatic solvents
• Relative Evaporation Rate: moderate, slower than acetone but faster than higher-boiling glycol ethers

These properties make PGME an effective coupling solvent that bridges aqueous and organic systems, and an excellent carrier for resins, dyes, and polymers.

Common Research and Industrial Applications

PGME finds broad application across multiple sectors:

• Semiconductor and Microelectronics: PGME is widely used as a solvent and co-solvent in photoresist formulations and as a rinse/cleaning agent in photolithography processes. Its ability to dissolve a variety of polymeric photoresist materials and its controlled evaporation rate make it a preferred choice.
• Coatings and Inks: PGME serves as a coalescing agent and solvent in water-based and solvent-based paints, lacquers, and printing inks, improving film formation and flow.
• Chemical Synthesis: It is used as a reaction medium and extraction solvent in laboratory-scale organic synthesis.
• Cleaning Formulations: PGME's miscibility with water and organic solvents makes it effective in industrial and electronic component cleaning products.
• Pharmaceuticals and Cosmetics: PGME may be used as a carrier solvent in certain formulation applications, subject to regulatory approval.

Safety, Handling, and Storage

PGME is a flammable liquid (flash point ~32 °C) and must be handled with appropriate precautions:

• Personal Protective Equipment (PPE): Wear chemical-resistant gloves (e.g., nitrile), safety goggles, and lab coat. Use in a well-ventilated area or fume hood.
• Fire Hazard: Keep away from ignition sources, open flames, and heat. Use explosion-proof equipment when handling in bulk.
• Inhalation: Prolonged or repeated inhalation of vapors should be avoided. Occupational exposure limits should be observed (consult the SDS for jurisdiction-specific values).
• Skin and Eye Contact: May cause mild irritation. Flush with copious water for at least 15 minutes if contact occurs; seek medical attention if irritation persists.
• Storage: Store in a tightly closed container in a cool, dry, well-ventilated area away from heat sources, oxidizing agents, and direct sunlight. Typical storage temperature: room temperature (15–25 °C).
• Disposal: Dispose of in accordance with local, regional, and national regulations for flammable organic solvents.

Always consult the current Safety Data Sheet (SDS) provided by Aladdin Scientific before use.

Purity Grades and Specifications for Research Use

For research and analytical applications, the purity and specification of PGME can be critical. Aladdin Scientific offers 1-Methoxy-2-propanol (PGME) (SKU: M1530092B) suitable for laboratory use. Key specification parameters to consider when selecting PGME include:

• Purity (GC): Typically ≥99% for research-grade material; higher purity grades may be available for sensitive analytical applications.
• Water Content: Low water content is important for moisture-sensitive reactions; look for grades with specified water content by Karl Fischer titration.
• Isomeric Composition: Commercial PGME typically contains predominantly the 1-methoxy-2-propanol isomer; the ratio of isomers may affect certain applications.
• Residue on Evaporation: Critical for electronic-grade applications where non-volatile residues can affect device performance.

Contact Aladdin Scientific technical support for detailed certificates of analysis (CoA) or custom purity specifications.

Frequently asked questions

What is the difference between PGME and PGMEA, and can they be used interchangeably?

PGME (1-Methoxy-2-propanol) is the free hydroxyl form of the solvent, while PGMEA (Propylene Glycol Methyl Ether Acetate) is the acetate ester of PGME. PGME is miscible with water, making it useful as a coupling solvent and rinse agent, whereas PGMEA is less water-miscible and is more commonly used as a primary solvent for photoresist polymers in semiconductor lithography. They are not directly interchangeable; solvent selection depends on the specific formulation requirements, polymer solubility, and process compatibility.

Is PGME safe to handle in a standard laboratory setting?

PGME can be handled safely in a standard laboratory with appropriate precautions. Because it is a flammable liquid (flash point ~32 °C), it must be kept away from open flames and ignition sources, and used in a well-ventilated area or fume hood. Personal protective equipment including nitrile gloves, safety goggles, and a lab coat should be worn. PGME is considered to have lower acute toxicity than ethylene glycol ether analogs, but prolonged inhalation or skin exposure should be avoided. Always refer to the current SDS before handling.

What purity grade of PGME is recommended for photoresist or semiconductor applications?

For semiconductor and photoresist applications, high-purity electronic-grade PGME is typically required, with purity generally ≥99.5% by GC and stringent limits on metal ion content, non-volatile residues, and water content. Standard research-grade PGME (≥99% purity) is suitable for most laboratory synthesis and coating research applications. Please consult Aladdin Scientific's certificate of analysis for lot-specific data and contact technical support if electronic-grade specifications are required.

How should PGME be stored to maintain its quality over time?

PGME should be stored in a tightly sealed container, in a cool (15–25 °C), dry, and well-ventilated area away from heat, direct sunlight, and incompatible materials such as strong oxidizing agents. Containers should be kept closed when not in use to prevent moisture absorption and contamination. Under proper storage conditions, PGME is stable and maintains its quality for an extended period; refer to the product label and SDS for the specific shelf life indicated by the manufacturer.

Can PGME be used as a solvent in biological or cell culture experiments?

PGME is not a conventional solvent for biological or cell culture applications. Its use in such contexts is not well-established and cytotoxicity data at relevant concentrations may be limited. Researchers considering PGME for biological applications should first conduct cytotoxicity assessments and consult available toxicology literature. For most biological solubilization needs, more commonly validated solvents such as DMSO or ethanol are preferred.

References

1. Dow Chemical Company. Propylene Glycol Ethers Technical Overview. Product safety and physical property data for PGME (1-Methoxy-2-propanol, CAS 107-98-2).
2. National Institute for Occupational Safety and Health (NIOSH). Chemical Hazard Information for 1-Methoxy-2-propanol (CAS 107-98-2). NIOSH Pocket Guide to Chemical Hazards.
3. Aladdin Scientific. Product Information and Safety Data Sheet: 1-Methoxy-2-propanol (PGME), SKU M1530092B.
4. Riddick, J.A.; Bunger, W.B.; Sakano, T.K. Organic Solvents: Physical Properties and Methods of Purification, 4th ed. Wiley-Interscience, 1986.

Products are supplied for research and development use only. Not for use in humans, animals, diagnosis, or therapy.