Functional Solvent Overview

• 🏭 Manufacturer: Multiple global suppliers (fragrance-grade)

• 🔎 Chemical Name: Oxydipropanol

• 🧪 Synonyms: Dipropylene glycol, DPG, Oxydipropyl alcohol

• 🧬 Chemical Formula: C₆H₁₄O₃

• 📂 CAS N°: 25265-71-8

• 📘 FEMA: Not listed (not applicable to food)

• ⚖️ MW: 134.17 g/mol

• 📝 Odor Type: Neutral

• 📈 Odor Strength: Very low

• 👃🏼 Odor Profile: Nearly odorless to faintly sweet (trace)

• ⚗️ Uses: Solvent, Fixative, Humectant

• 🧴 Appearance: Clear, colorless, viscous liquid

What is Dipropylene Glycol?

Dipropylene Glycol is a synthetic aliphatic diol produced during the hydration of propylene oxide. Commercial DPG is typically a mixture of structural isomers, all sharing similar functional properties. It is chemically related to propylene glycol and often produced as a secondary product in PG manufacturing. In perfumery, only fragrance-grade DPG is used, which is refined to minimize impurities and ensure high solvency with low sensory interference.

Historical Background

The use of glycols in perfumery and personal care dates back to the early 20th century, but dipropylene glycol became commercially prominent in the 1950s alongside growing demand for stable, low-volatility solvents. As production of propylene oxide increased for polymers and antifreeze, DPG emerged as a high-performance secondary material, particularly valued in fragrance design and room-freshening applications for its low vapor pressure and broad compatibility.

Olfactory Profile & Perfumery Applications

DPG is virtually odorless, especially in high-purity grades, and does not contribute to the fragrance profile. However, its solvent behavior directly impacts the performance of volatile ingredients.

• Used as a fixative and diluent for essential oils, absolutes, and synthetic aroma chemicals

• Slows evaporation of top notes, improving fragrance longevity

• Improves solubility of polar and non-polar ingredients in alcohol-free or low-alcohol systems

• Common in:

  • Roll-on and oil-based perfumes

  • Room sprays and reed diffusers

  • Fragrance concentrates for industrial and personal care use

Recommended use levels vary from 10% to 90%, depending on format and volatility requirements.

Industrial & Technical Uses

• Cosmetics and Skincare: Humectant and emollient in lotions, creams, and conditioners

• Air Fresheners: Carrier for fragrance actives in aerosols and electric diffusers

• Technical: Intermediate in resin and plasticizer synthesis

• Industrial Fluids: Component in low-freeze-point hydraulic and de-icing fluids (non-fragrance grade only)

Regulatory & Safety Overview

• IFRA: Not restricted (no limitation in Categories 1–12)

• CIR Review: Confirmed safe for topical use in rinse-off and leave-on products

• EU Cosmetics Regulation: Permitted with no specific concentration limits

• FEMA GRAS: Not applicable (non-food use only)

• Toxicology:

  • Low acute toxicity

  • Non-sensitizing

  • Minimal dermal and ocular irritation in cosmetic grade

Fragrance-grade DPG should not be confused with industrial-grade DPG, which may contain impurities and should not be used on skin.

Environmental Impact

• Biodegradability: Readily biodegradable under aerobic conditions

• Aquatic Toxicity: Low

• Bioaccumulation: Not expected

• Air Emissions: Low vapor pressure minimizes VOC release in standard applications

• Waste Handling: Dispose according to local chemical waste regulations; avoid environmental discharge of industrial-grade DPG

Additional Information

• Boiling Point: ~230 °C

• Flash Point: ~124 °C (closed cup)

• Density @ 20 °C: ~1.02 g/cm³

• Viscosity: Moderate to high, temperature-dependent

• Solubility:

  • Miscible with water, ethanol, glycerol, and glycols

  • Compatible with esters, aldehydes, and many perfumery raw materials

• Format Compatibility: Excellent in oil blends, sprays, roll-ons, and emulsions

• Storage Conditions: Store sealed, in a cool, dry place away from strong oxidants

Sources

• Scentspiracy-provided source

• PubChem Database – Dipropylene Glycol

• CIR Final Safety Assessment (2020)

• IFRA Standards Library (2024)

• ECHA Substance Database

• Sell, C. (2006). The Chemistry of Fragrances

• Arctander, S. (1960). Perfume and Flavor Chemicals