Nearly odorless, faintly sweet. Dipropylene glycol is a perfumer's blank canvas — a solvent that dissolves, dilutes, and carries fragrance without contributing any scent of its own.
Essentially odorless. At high concentration, a very faint, slightly sweet, glycol-like quality. No aromatic character. Functions as an olfactory blank — its purpose is to be undetectable.
Evolution over time
Immediately
Immediately
No perceptible scent.
After a few hours
After a few hours
No olfactory evolution. Odorless carrier.
After a few days
After a few days
No scent. Functional solvent only.
The Full Story
Dipropylene glycol (DPG) — CAS 25265-71-8, C₆H₁₄O₃ [A] — is the perfumer's blank canvas. A colourless, viscous diol with almost no scent of its own (a faint sweet-glycolic whisper at high concentration), DPG dissolves a wide range of aroma molecules and serves as the standard diluent for evaluation strips, accord-mixing, and finished-formula carriers. It is a mixture of three isomers (the head, the symmetrical and the tail) sold in two grades — perfumery (premium-low-odour) and industrial.
Use
DPG appears in nearly every modern alcohol-based and oil-based fragrance, typically at 1–10% of the finished concentrate as a balancer of viscosity and as a diluent for high-impact materials. It is also the default 10% dilution medium when perfumers evaluate raw materials on smelling strips. Compared to alternatives — ethanol, isopropyl myristate, triethyl citrate — DPG has lower volatility (good for fixative) and a cleaner odour profile (no fermented or fatty notes).
Every perfumery student in the world learns to evaluate raw materials diluted in DPG — typically at 10% concentration on paper blotters. The phrase 'smell it in DPG' is the perfumery equivalent of 'look at it under the microscope.'
Extraction & Chemistry
Extraction method: Produced industrially by acid-catalyzed hydration of propylene oxide. Entirely petrochemical. Large-scale production as a co-product of propylene glycol manufacturing. Very inexpensive.
Molecular Formula
C6H14O3
CAS Number
25265-71-8
Botanical Name
N/A - synthetic molecule
IFRA Status
No known restrictions
Synonyms
DPG, Dipropylene glycol
Physical Properties
Appearance
Colorless clear oily liquid
Boiling Point
230.00 to 231.00 °C. @ 760.00 mm Hg
Flash Point
245.00 °F. TCC ( 118.33 °C. )
Specific Gravity
1.01900 to 1.02100 @ 25.00 °C.
Refractive Index
1.43000 to 1.45000 @ 20.00 °C.
In Perfumery
Solvent, diluent and carrier. DPG is used to dilute aroma chemicals for evaluation (standard 10% dilutions in DPG are a perfumery-school staple) and to extend the dry-down of volatile materials in finished formulas. It does not contribute meaningful aroma. DPG appears in nearly every modern alcohol-based and oil-based fragrance, typically at 1–10% of the concentrate.
