Dioctyl Phthalate (DOP / DEHP)
For fifty years the reference plasticiser against which every other was measured. It is now a Category 1B reproductive toxicant on the REACH Authorisation List, and the position differs sharply between markets.
Molecular Structure
What is Dioctyl Phthalate (DOP / DEHP)?
DOP, more precisely named DEHP, is the di(2-ethylhexyl) ester of phthalic acid — a benzene ring with two ester groups on adjacent carbons, each carrying a branched eight-carbon chain. Those chains sit between PVC molecules and hold them apart, letting the chains slide over one another, which is what converts a rigid polymer into a flexible one.
It is made by esterifying phthalic anhydride with 2-ethylhexanol. The combination of plasticising efficiency, low volatility, good low-temperature performance and low cost made it the industry standard for decades, and much of the technical literature on PVC formulation is still written with DOP as the reference point.
The regulatory position has since diverged. In the EU, DEHP is classified as toxic to reproduction, listed as a Substance of Very High Concern, placed on the Authorisation List, and restricted in toys, childcare articles and a wide range of plasticised articles. In much of Asia, Africa and Latin America it remains in routine large-volume use.
DEHP is on REACH Annex XIV, meaning its use in the EU requires an authorisation granted for a specific application, and Annex XVII entry 51 restricts it above 0.1% in toys, childcare articles and a broad range of plasticised articles. Anyone specifying DOP for a chain that touches the EU, or any market following it, should confirm the position for the specific article before committing volume.
Quick Reference
Key Physical & Chemical Properties
Structure & Bonding
Two ester groups on adjacent carbons of a benzene ring, each carrying a branched eight-carbon chain. That ortho arrangement is what distinguishes a phthalate from a terephthalate — and it is the structural feature the toxicological concern attaches to.
Skeletal structure — ortho-diester with two 2-ethylhexyl chains
Structural Identity
- IUPAC NameBis(2-ethylhexyl) benzene-1,2-dicarboxylate
- Common namesDOP, DEHP, dioctyl phthalate
- Molecular FormulaC₂₄H₃₈O₄
- Molecular Weight390.56 g/mol
- SubstitutionOrtho (1,2) on the benzene ring
- Ester chains2-Ethylhexyl, branched C₈
- Made fromPhthalic anhydride + 2-ethylhexanol
- EU classificationRepr. 1B, H360FD
- RegulatorySVHC; Annex XIV authorisation; Annex XVII entry 51
- CAS Number117-81-7
- InChI KeyBJQHLKABXJIVAM-UHFFFAOYSA-N
Product Specifications
Chelora supplies Dioctyl Phthalate (DOP / DEHP) in standard and custom grades. Contact us for specification sheets tailored to your process.
| Chemical name | Di(2-ethylhexyl) phthalate |
|---|---|
| CAS Number | 117-81-7 |
| Molecular formula | C₂₄H₃₈O₄ |
| Molecular weight | 390.56 g/mol |
| Ester content (min) | ≥ 99.50 wt% |
| Acid value as phthalic acid (max) | ≤ 0.07 mg KOH/g |
| Colour (max) | ≤ 30 Pt-Co (Hazen) |
| Water (max) | ≤ 0.10 wt% |
| Specific gravity | 0.983 – 0.986 at 20/20 °C |
| Refractive index | 1.485 – 1.487 at 20 °C |
| Volatility / heating loss (max) | ≤ 0.20 wt% at 125 °C, 2 h |
| Free 2-ethylhexanol (max) | ≤ 0.10 wt% |
| Volume resistivity (electrical grade, min) | ≥ 1 × 10¹¹ Ω·cm |
| Flash point | 215 °C (closed cup) |
| Autoignition temperature | 390 °C |
| Pour point | −55 °C |
| Regulatory status | EU: Repr. 1B, SVHC, Annex XIV, Annex XVII entry 51 |
| Transport classification | Not regulated as dangerous goods |
Downstream Applications & Derivatives
Key derivative chains and industrial uses of Dioctyl Phthalate (DOP / DEHP).
Cable Insulation & Sheathing
Plasticised PVC compound for wire and cable, the largest single outlet in markets where DOP remains in general use.
Flooring & Wallcovering
Vinyl sheet and tile flooring, wall covering and coated fabric, where plasticiser level sets flexibility, wear and embossing behaviour.
Film, Sheet & Hose
Calendered flexible film and sheet, garden and industrial hose, gaskets, seals and inflatables across general industrial use.
Automotive Interior
Instrument panel skin, door trim, underbody sealant and sound-deadening compound, in markets where phthalate use is unrestricted.
Footwear & Consumer
Vinyl footwear, bags, sports goods and general moulded consumer articles — the segment most affected by restriction where it applies.
Capacitor & Electrical
Dielectric fluid and electrical grade compound, where the specification runs on volume resistivity rather than mechanical performance.
Why source Dioctyl Phthalate (DOP / DEHP) through Chelora Petrochem?
Verified Origin
Full origin certification and asset-backed supply chain documentation — no grey-market supply for a substance under authorisation.
Grade Flexibility
General purpose and electrical grades supplied. We certify acid value, colour, volatility and — for electrical grades — volume resistivity, which is what compounders actually buy on.
Full Documentation
CoA, SDS, REACH compliance with SVHC communication under Article 33, and written confirmation of the regulatory position for your declared destination market and article type.
Logistics Support
Experienced in bulk plasticiser logistics — ISO tanks, road tankers, drums and IBCs, for Indian and international delivery.
Storage & Handling Guidelines
Always refer to the full SDS before handling. The following is a summary of key requirements.
- Confirm the regulatory position for the destination market and the specific article before committing to a supply position. DOP is unrestricted in some markets, restricted in others and subject to authorisation in the EU, and the difference is commercial rather than technical.
- Pass SVHC information down the supply chain. REACH Article 33 obliges suppliers of articles containing DEHP above 0.1% to communicate that fact, and the obligation follows the article rather than the substance.
- Store in mild steel or stainless tanks at ambient. DOP is stable, non-corrosive and needs no blanketing, though heating to around 40 °C eases pumping in cold weather.
- Keep dry and clean. Water and particulates carried into a PVC compound show as clarity defects and can affect electrical resistivity, which is the governing specification for cable grades.
- Protect from prolonged heat and air, which slowly raise the acid value through hydrolysis and degrade colour.
- Segregate general purpose from electrical grade. Volume resistivity is easily spoiled by trace ionic contamination and cannot be recovered by filtration.
- Control skin contact as a routine matter. DOP is not corrosive or acutely toxic, but the reproductive toxicity classification means repeated dermal exposure should be prevented rather than tolerated.
- Contain spills and prevent release to drains and surface water. DOP is persistent and adsorbs strongly to sediment.
- Provide extraction where plasticiser is heated during compounding or calendering, since fume and mist are generated at process temperature.
Hazard Summary
Classification: Repr. 1B (H360FD, may damage fertility and may damage the unborn child). DEHP is on the REACH Candidate List as a Substance of Very High Concern for both human health and endocrine-disrupting properties, and is listed on Annex XIV, the Authorisation List.
Authorisation and restriction in the EU: Annex XIV listing means use of DEHP in the EU requires an authorisation granted for a specified application, with a sunset date long passed. Separately, Annex XVII entry 51 restricts DEHP together with DBP, BBP and DIBP above 0.1% by weight in toys and childcare articles and, since July 2020, in a wide range of plasticised articles. Medical devices containing DEHP carry labelling obligations. Confirm the position for the specific article and market before committing.
The concern is structural: the reproductive toxicity of ortho-phthalates is associated with the monoester formed when one chain hydrolyses off, which interferes with foetal testosterone production. It is a property of the ortho arrangement and the chain length, which is why terephthalates and shorter or longer phthalate esters do not carry the same classification.
Migration: DEHP is not chemically bound to the PVC and migrates out over time, particularly into fatty media and under heat. That is the mechanism behind both the loss of flexibility in aged articles and the exposure concern in food contact and medical applications.
Acute toxicity is low: DOP is not corrosive, not sensitising and has very low acute toxicity by all routes. The hazard is entirely chronic and regulatory, which is precisely why it went unremarked for decades.
Environmental: persistent, adsorbs strongly to sediment, and identified as an endocrine disruptor in the environment. Contain releases and prevent discharge to water.
Fire: a combustible liquid with a flash point of 215 °C. Not a flammable liquid and not regulated for transport, but heated handling during compounding should be assessed.
PPE minimum: safety glasses, gloves and coveralls preventing routine skin contact, with extraction where plasticiser is heated.
Consult the full SDS and confirm the regulatory status for your destination market and article before use.
Frequently Asked Questions
Technical and commercial questions about Dioctyl Phthalate (DOP / DEHP) sourcing and specifications.
What is DOP used for?
Flexible PVC, in all its forms. Cable insulation and sheathing is the largest outlet, followed by vinyl flooring, wall covering and coated fabric, calendered film and sheet, hose, gaskets and inflatables. In markets where it remains unrestricted it also goes into automotive interior trim and sealant, vinyl footwear and general moulded consumer articles. Electrical grades serve capacitor and cable applications where volume resistivity is the governing specification.
Are DOP and DEHP the same thing?
In commercial practice, yes, and the loose naming causes real confusion. DEHP — di(2-ethylhexyl) phthalate — is the specific substance, CAS 117-81-7. DOP, dioctyl phthalate, is a trade name that in principle could describe any di-octyl phthalate ester but in practice almost always means DEHP, because 2-ethylhexanol is the alcohol used. Since DEHP is the name that appears in regulations and DOP is the name that appears on invoices, it is worth confirming CAS 117-81-7 on the paperwork rather than relying on either name, particularly when a document has to satisfy a regulator.
What is the regulatory position on DOP?
It depends entirely on the market. In the EU, DEHP is classified as toxic to reproduction, listed as an SVHC for both human health and endocrine-disrupting properties, placed on the Authorisation List so that use requires a specific authorisation, and restricted above 0.1% in toys and childcare articles and in a wide range of plasticised articles under Annex XVII entry 51. Several other jurisdictions have adopted comparable restrictions on consumer articles. In much of Asia, Africa and Latin America, DOP remains in routine large-volume industrial use. The practical implication is that a supply position has to be taken against a specific destination and article type, not against the substance in general.
Why do terephthalates avoid the classification that phthalates carry?
Because of where the ester groups sit on the ring. The reproductive toxicity associated with certain ortho-phthalates is attributed to the monoester formed when one of the two chains hydrolyses off in the body, which interferes with testosterone synthesis in the developing foetus. That activity depends on the geometry of the ortho arrangement and on the chain being in a particular size range. Terephthalates, with the esters para to one another, produce a monoester that does not have the same activity, and dioctyl terephthalate is accordingly not classified as a reproductive toxicant. It is one of the clearer cases where moving a substituent around a ring changes the regulatory outcome completely.
What is replacing DOP?
Three directions. Higher phthalates — DINP and DIDP — have longer, more branched chains that fall outside the size range associated with the classification, and they carry lighter restrictions, though they face their own scrutiny. Dioctyl terephthalate is the direct non-phthalate substitute, chemically closest and increasingly the default in regulated markets. Beyond those sit purpose-designed non-phthalates including DINCH, citrates and adipate esters, chosen where a specific performance or a specific approval is required. For most general flexible PVC the practical replacement in a restricted market is DOTP.
What documentation does Chelora provide?
Every shipment includes a Certificate of Analysis covering ester content, acid value, colour, water, specific gravity, refractive index, volatility, free 2-ethylhexanol and, for electrical grades, volume resistivity; a Safety Data Sheet to GHS and REACH format; SVHC communication under REACH Article 33; confirmation that the material is not regulated as dangerous goods; an origin certificate; and written confirmation of the regulatory position for the declared destination market and article type.
Request a quote or specification sheet
Talk to Chelora's sourcing team about Dioctyl Phthalate (DOP / DEHP) grade, volume, logistics, documentation, and lead times. We respond within one business day.
