RUŌOD Lab

Diethyl Phthalate (DEP)

Solvent or carrier · No odour family

odourless — base note.

Aroma illustration for Diethyl Phthalate (DEP): a clear droplet with ripples, for its odourless note. It illustrates smell associations, not the material or its source.Skeletal formula of Diethyl Phthalate (DEP) (Ethyl phthalate), C12H14O4, drawn from PubChem's 2D record. Stereochemistry is not shown.
Aroma View: an illustration of what Diethyl Phthalate (DEP) smells like (odourless), drawn by RUŌOD Lab — not its appearance or its source.Skeletal formula drawn by RUŌOD Lab from PubChem's 2D record (CID 6781). Stereochemistry is not shown; the coloured background is decoration.
Images

By the RUŌOD Lab TeamRevision 1Updated

In short

Diethyl phthalate (DEP) is a nearly odourless ester long used as a solvent and fixative-diluent in fragrance oils. Many brands now avoid it and use DPG, IPM or triethyl citrate instead.

What Diethyl Phthalate (DEP) smells like

Diethyl phthalate (DEP) is a clear, colourless, oily liquid that supplier specifications describe as nearly or practically odourless, or with very little odour; one distributor mentions a slight aromatic odour. It has long been used as a solvent and fixative that dilutes perfume oils and slows the evaporation of volatile notes. Concerns about phthalates have led many to replace it with triethyl citrate.

Leading note
No single note leads in the published descriptions
Faint facets
Slight aromatic
Character
Neutral, oily, low-volatility
  • odourless

What makes Diethyl Phthalate (DEP) distinctive

The older oily diluent of perfume oils, now often replaced by triethyl citrate over concerns about phthalates.

How Diethyl Phthalate (DEP) is used

Used as a solvent and fixative for perfume oils; triethyl citrate is often used in its place.

Typical role: solvent (dilutes or carries other materials).

How Diethyl Phthalate (DEP) differs from similar materials

Triethyl Citrate
Triethyl citrate is positioned as DEP's replacement, nearly odourless with a faint fruity, wine-like nuance when smelled neat.
Benzyl Benzoate
Benzyl benzoate is also a solvent and fixative but has a faint sweet, balsamic, almond-like odour of its own.

An asterisk marks a difference that a cited source states directly. The others compare the published descriptions of each material. Smell varies with grade, supplier and dilution; compare them side by side on blotters before substituting one for another.

Formulation considerations

Some retailers and brands exclude phthalates as a policy; check your market and your customers' requirements before using it.

Identity and classification

Type
Solvent or carrier
Origin
Synthetic
Odour family
No odour family
Note position
Base note
Physical form at room temperature
Liquid
Also known as
Ethyl phthalate, DEP
CAS number
84-66-2
Molecular formula
C12H14O4
Molecular weight
222.24 g/mol
IUPAC name
diethyl benzene-1,2-dicarboxylate

The CAS number, formula and molecular weight are taken from PubChem compound 6781, whose own record lists this CAS number; checked 19 October 2026.

Safety and compliance

Hazard classification of the neat substance, as PubChem summarises it, read 26 October 2026. Companies notifying the ECHA C&L Inventory report it as not meeting the GHS hazard criteria (1,710 of 1,769 reports). Unless it is harmonised, this is the notifiers' own classification, not a binding one.

This page is general information, not a safety assessment or a specification. Confirm identity, composition, IFRA status and allergen content from your supplier's documents for the lot you hold.

Materials it works with

Used in formulas and accords

Used in 2 published formulas

Diethyl Phthalate (DEP) is an ingredient in 2 perfume formulas in the Formula & Accord Library.

Further reading

Questions about Diethyl Phthalate (DEP)

Is Diethyl Phthalate (DEP) natural or synthetic?

Diethyl Phthalate (DEP) is synthetic — it is made by chemical synthesis.

What is the CAS number of Diethyl Phthalate (DEP)?

84-66-2. It was checked against PubChem on 19 October 2026.

Which published formulas use Diethyl Phthalate (DEP)?

Diethyl Phthalate (DEP) is used in 2 published formulas in the RUŌOD Lab Formula & Accord Library: Black Musk and Hindi Maliki Qadeem. Each is listed with a link under "Used in formulas and accords" on this page.

Sources

Your own records, next to the reference

Keep your own record of Diethyl Phthalate (DEP) — supplier, cost, stock, dilutions and where it is used — in RUŌOD Lab's material library.

The material library All materials