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Ingredient Glossary · Solvents & Fixatives

DEP — Diethyl

Diethyl benzene-1,2-dicarboxylate · CAS 84-66-2 · Phthalate Ester

Khushbu ka buniyadi hal (خوشبو کا بنیادی حل) — the invisible workhorse of global perfumery. Virtually odourless, yet the universal foundation carrier for attars, agarbatti, and EDP compounds. IFRA-unrestricted, halal, and the broadest-solvency fragrance ingredient available. DEP makes every other ingredient perform at its best.

CAS
84-66-2
Identifier
1.120
g/cm³
Density @20°C
No
Restrict.
IFRA 51st
Scroll
Quick Reference

At a Glance

Common Names
DEP · Diethyl Phthalate · Palatinol A · Neantine · Kodaflex DEP · o-Phthalic Acid Diethyl Ester
CAS / EINECS
CAS 84-66-2 · EINECS 201-550-6
InChI Key: FLKPEMZONWLCSK-UHFFFAOYSA-N
Molecular Formula
C₁₂H₁₄O₄ · MW 222.24 g/mol
Diethyl ester of phthalic acid · LogP 2.42–2.47
Physical Form
Clear, colourless oily liquid · BP 298°C · Density 1.120 g/cm³ · RI 1.5025 · Flash point 146°C
Vapour Pressure
~0.002 mmHg at 20°C — exceptionally low volatility · Basis of fixative action (Raoult's Law)
GC Purity (Bio Shop™)
≥99.5% GC · APHA ≤10 · Acid value ≤0.1 mg KOH/g · Water ≤500 ppm · Fragrance grade
Solubility
Miscible with alcohols, esters, most fragrance oils · Immiscible with water · Compatible with Perfume Premix and DPG
Halal Status
✓ Halal — 100% synthetic. Phthalic anhydride (petrochemical) + ethanol (fully consumed in esterification). No animal inputs, no residual ethanol in finished product
Odour Character
Virtually odourless at fragrance grade — khushbu ka buniyadi hal (خوشبو کا بنیادی حل). Trace chemical background at undiluted; faint plastic note in below-specification material only
Primary Function
Universal solvent, fixative, carrier, and diluent. The broadest-solvency single fragrance ingredient: co-dissolves polar and non-polar aroma chemicals in one system
IFRA Status (51st)
✓ Not restricted — unrestricted use across all 12 IFRA categories. RIFM assessment confirmed no safety concern for fragrance use
EU Cosmetics Status
✓ NOT listed in Annex II (prohibited substances). DEP is distinct from DEHP, DBP, BBP (which ARE prohibited). No mandatory declaration required
Typical Usage Level
Attar base: 60–90% · Compound fixative: 5–20% · Body spray carrier: 30–60% · Agarbatti soaking oil: up to 95%
Shelf Life (sealed)
3–5 years sealed, stored below 30°C. Hydrolysis (rising acid value) is primary degradation risk in hot/humid Pakistan conditions
Introduction

The Invisible Workhorse of Perfumery

Diethyl Phthalate — universally known in the fragrance trade as DEP — occupies a paradoxical position in perfumery: it is perhaps the most important ingredient most consumers have never heard of. Unlike every other material documented in this Ingredient Glossary, DEP does not provide a rose note, a woody chord, or a musky warmth. Instead, it does something more quietly powerful: it creates the perfect chemical environment for every other ingredient to perform at its best. In the language of Pakistani attar makers, DEP is the khushbu ka buniyadi hal (خوشبو کا بنیادی حل) — the foundation solvent for fragrance — the invisible medium that makes long-lasting, beautifully balanced attars possible.

DEP's value arises from a unique combination of properties. Its density (1.120 g/cm³) is greater than water; its boiling point (298°C) is among the highest of any fragrance-grade liquid; and its vapour pressure (0.002 mmHg at 20°C) is roughly 80 times lower than common terpene alcohols. This extreme low volatility is what makes DEP an exceptional fixative: by physically retarding the evaporation of volatile aroma chemicals via Raoult's Law, DEP extends the presence of fragrance on skin, fabric, and diffuser media by 20–50% compared to the same compound without DEP. For Pakistani consumers who prize dil tak mehkna (دیر تک مہکنا) — fragrances that last — DEP's mechanism aligns perfectly with cultural preference.

Its solvating power — the ability to dissolve the widest possible range of aroma chemicals in a single medium — is equally distinctive. DEP's mid-range LogP of 2.42 positions it exactly between polar DPG (LogP 0.59) and non-polar IPM (LogP 7.25), allowing it to co-dissolve hydrophilic materials like hydroxycitronellal alongside lipophilic materials like polycyclic musks in one clear, haze-free formula. No single alternative covers the same range, which is why DEP dominated global fragrance production throughout the 20th century and continues as the backbone of Pakistan's attar and agarbatti industries today.

Bio Shop™ Pakistan — Sourcing Note

Bio Shop™ Pakistan stocks DEP at fragrance grade ≥99.5% GC purity — the same specification used by international fragrance houses. Supplied as a clear, colourless oily liquid in sealed HDPE containers. Primary role: universal fragrance solvent, fixative, and attar carrier base. Typical attar use: 60–90% of formula. Typical compound use: 5–20% as fixative. GC certificate and acid value data available with every batch. Visit bioshop.pk/products/dep-diethyl-phthalate for current stock and pricing.

Molecular Identity

Chemical Identification

IUPAC NameDiethyl benzene-1,2-dicarboxylate
Systematic Name1,2-Benzenedicarboxylic acid, diethyl ester
CAS Number84-66-2
EINECS / EC201-550-6
Formula / MWC₁₂H₁₄O₄ · 222.24 g/mol · SMILES: CCOC(=O)c1ccccc1C(=O)OCC
Structural ClassOrtho-phthalate ester · aromatic dicarboxylate diester
Functional GroupsTwo ester groups (–COO–) · aromatic benzene ring at 1,2 positions · two ethyl chains
Degree of Unsat.5 — benzene ring (4) + two C=O carbonyls contribute 2; offset by O giving net 5
Synthesis RouteEsterification of phthalic anhydride + ethanol; H₂SO₄ catalyst; 115–150°C; two-stage (ring opening → second esterification); yield 95–98%
Physical PropertiesDensity 1.120 g/cm³ · BP 298°C · MP −40°C · Flash point 146°C · RI 1.5025 · VP 0.002 mmHg · LogP 2.42–2.47
Natural OccurrenceDEP does not occur naturally. Feedstocks (phthalic anhydride from o-xylene or naphthalene; ethanol from petroleum or fermentation) are industrially derived. Ethanol is fully consumed in synthesis — no residual ethanol in product
Urdu / Pakistanڈی ای پی · خوشبو کا بنیادی حل (Khushbu Ka Buniyadi Hal) · دیر تک مہکنا (Deer Tak Mehkna)
Grade & Purity Profiles

Four Commercial Grades

DEP is commercially available in several purity grades. Understanding these differences is critical for Pakistani formulators: the domestic market occasionally circulates technical-grade or adulterated material that can introduce off-notes, haze, and accelerated degradation in finished fragrance products. Bio Shop™ Pakistan stocks fragrance grade ≥99.5% GC exclusively — the professional specification for all perfumery applications.

Professional Standard · Bio Shop™ Grade
Fragrance Grade
≥99.5% GC · APHA ≤10 · Acid value ≤0.1 mg KOH/g · Water ≤500 ppm
GC Purity
≥99.5%
Density 1.118–1.122 · RI 1.501–1.504 · Flash point ≥140°C
"The only grade suitable for skin-contact fragrance applications. Water-white, clear, essentially odourless. Bio Shop™ Pakistan primary stock. GC certificate with each batch. Use at 5–30% as compound fixative; 60–90% as attar carrier base."
Industrial · Not Recommended for Skin-Contact
Technical Grade
99.0% GC · APHA 10–25 · Higher MEP impurity · Residual process odour
GC Purity
99.0%
Used in plasticisers, varnishes, industrial processes — not premium fragrance
"May carry a faint chemical background odour from residual monoethyl phthalate or process impurities. Colour may be APHA 10–25 (faint yellow). Not recommended for premium attar or fine fragrance work. Widely available on Pakistan industrial chemical market at lower cost — verify specification before use."
Pharma Grade · NF Specification
Pharmaceutical / NF
≥99.5% GC · National Formulary specification · Additional identity tests
GC Purity
≥99.5%
Used as enteric coating plasticiser in pharmaceutical tablets
"Similar purity to fragrance grade but with additional pharmaceutical identity testing. Suitable for fragrance applications if purity certificate confirms fragrance-grade specifications. Higher cost than fragrance grade — no fragrance performance advantage. Not stocked by Bio Shop™ Pakistan for fragrance use."
⚠ Avoid Without Verification
Adulterated / Unknown
Pakistan grey market · Mineral oil dilution · High MEP · DPG substitution
Actual Density
Unknown
Density below 1.100 = dilution. Acid value above 0.5 = degraded
"Common adulterants: mineral oil (causes haze in finished fragrances, density drops below 1.080); excessive monoethyl phthalate / MEP (acidic note, accelerates hydrolysis); DPG substitution (density ~1.023 — immediately detectable by weighing 10mL sample). Always request a batch-specific GC certificate from any supplier."
Dosage Science

Concentration Behaviour

DEP is unique among fragrance ingredients in being useful across an extraordinary range of concentrations — from trace fixative at 1% to primary carrier at 95% — without any olfactory ceiling concern. Since DEP itself contributes no aroma, there is no "overdose" in the olfactory sense. The selection of usage level is entirely driven by the product type and the technical function required: fixation, solvation, longevity improvement, or bulk carrier. Pakistani formulators should understand each concentration band and its distinct technical effect.

1–5% in CompoundTrace Fixative
Subtle longevity improvement in alcohol-based fine fragrance compounds. Helps solubilise problem ingredients (e.g. crystalline coumarin, nitromusks) at trace level. Effectively invisible contribution — use when minimal DEP presence is required for phthalate-free adjacent positioning
5–15% in CompoundModerate Fixative
Clear longevity improvement; slight smoothing of sharp aroma chemicals. Ideal for fragrance compounds used in EDP and EDT sprays, body lotions, and hair serums. Improves dissolution of challenging materials. Extends skin longevity 15–25% vs. compound without DEP
15–30% in CompoundStrong Fixative
Strong fixation and longevity; carrier function emerging alongside fixative role. Standard for body spray concentrates, fabric sprays, and premium attar compounds. Enables full solubilisation of polycyclic musks (galaxolide, tonalide) and difficult materials at high loading
30–60% of FormulaDominant Carrier
DEP becomes the primary carrier medium; full solvation support for all aroma chemical classes. Typical for attar compounds at medium dilution, agarbatti soaking oils, and reed diffuser bases. The rich, smooth character of mid-concentration DEP attars is widely appreciated in Pakistan and Gulf markets
60–90% of FormulaPrimary Attar Base
DEP is the primary liquid matrix; aroma chemicals at 10–40% total. The classic Pakistani roll-on attar structure. DEP's smooth, skin-conditioning oil film provides the iconic "quality feel" that consumers associate with premium attars. Non-greasy at thin film application levels typical of roller-ball dabba
90–100% of FormulaAgarbatti / Industrial Base
DEP as single-solvent carrier; fragrance compound at 5–10% only. Standard for agarbatti bamboo stick soaking oil and bakhoor wood chip preparation. DEP penetrates wood and charcoal uniformly due to its low surface tension and excellent wettability, ensuring even fragrance distribution throughout the stick
Functional Analysis

How DEP Shapes the Pyramid

Application · 0–5 min
Invisible Clarity
DEP contributes nothing olfactorily at application — top notes open with complete clarity, unobstructed by any carrier character. This "invisible opening" is one of DEP's most important practical advantages over older attar bases: where sandalwood oil or inferior mineral oil carriers add their own aroma to the opening, fragrance-grade DEP is genuinely absent from the olfactory experience. In Pakistan's summer heat — Lahore at 42°C, Karachi at 38°C — DEP's high boiling point prevents the explosive "solvent blast" that alcohol-based fragrances produce in heat. Instead, the top note unfolds at a measured, controlled pace, creating a sophisticated opening rather than an aggressive one. Pakistani attar buyers consistently describe DEP-based attars as feeling "premium" and "clean" without being able to identify the ingredient responsible for this quality.
Heart · 30 min–2 hr
Smoothing & Harmonising
As volatile top notes depart and heart materials develop, DEP's vapour pressure depression effect (Raoult's Law) begins to show its character: the transition from top to heart is smoother than in DEP-free formulas. Very sharp aroma chemicals — high-impact aldehydes such as Aldehyde C11 Undecylenic, intense citrus terpenes, or aggressive top-note musks — have their perceived sharpness moderated by DEP's physical retardation effect. Jean-Claude Ellena and other fine fragrance masters of the 20th century recognised this "note depression" as a creative tool: DEP enabled them to use challenging materials at their optimal olfactory concentration while preventing them from dominating the opening harshly. For Pakistani oriental compound builders working with oud oil, rose oxide, or indole, DEP provides the same smoothing without requiring a reduction of the key ingredient.
Base · 4–8 hr
Extended Retention
DEP's most celebrated practical contribution is the extension of base-note longevity on skin. By remaining on the skin surface as a low-volatility liquid film, DEP continues to act as a reservoir from which base materials (oud, musk, sandalwood, benzyl benzoate) are released gradually over many hours. A DEP-based attar on Pakistani skin at 40°C may retain meaningful fragrance character for 8–12 hours, while the same compound in DPG alone might fade in 4–6 hours. This "deer tak mehkna" (دیر تک مہکنا — long-lasting scent) quality is the primary commercial selling point of traditional South Asian attars and the reason DEP has remained the preferred carrier in this category for over a century. Oud-based compounds, which contain expensive high-boiling sesquiterpene materials, benefit particularly strongly from DEP's retention effect.
Fabric · Next Day
Fabric Reservoir
DEP and the aroma chemicals carried within it partition strongly into textile fibres, creating a fabric-based fragrance reservoir that continues releasing scent for many hours after skin contact. Pakistani consumers who apply DEP-based attar to the collar of their shalwar kameez or the wrist-cuff of a kurta will notice a pleasant fragrance presence the following day as the fabric warms and releases the adsorbed materials. For agarbatti applications, DEP's adsorption into bamboo and charcoal fibres during soaking ensures that fragrance is retained within the stick material and released gradually during burning. This property makes DEP-based bakhoor and agarbatti consistently more fragrant than water-based or low-DEP formulations at equivalent aroma chemical loadings.
Odourless Fixative Smooth Carrier Long-lasting Transparent Harmonising Invisible Workhorse دیر تک مہکنا Universal Solvent Attar Base
Formulation Accords

Three Complete Formulas

Three production-ready formulas from the Bio Shop™ Pakistan reference document — exact weights, exact percentages. All ingredients available at bioshop.pk. Formula 1 is a DEP-based roll-on attar (no alcohol — halal for all markets). Formula 2 is an oriental masculine EDP compound with DEP as fixative co-carrier, using Perfume Premix as the sole alcohol base for the finished bottle. Formula 3 is a DEP-based agarbatti soaking oil for traditional Pakistani incense stick manufacturing.

Sheerin Gulab  ·  شیریں گلاب
Sweet Rose Attar · DEP-based, no alcohol · 100g batch · Roll-on dabba · Pakistani daily use & Eid gifting
DEP — Diethyl Phthalate (≥99.5%)78.00g  78%
Rose Wardia (pure)10.00g  10%
Phenyl Ethyl Alcohol — PEA (pure)5.00g  5%
Coumarin (solid — pre-dissolve)3.00g  3%
Benzyl Benzoate (pure)3.00g  3%
Gamma Methyl Ionone (pure)1.00g  1%
Method
Warm DEP to 30°C in HDPE vessel. Add coumarin and stir 5 minutes until fully clear (coumarin dissolves readily in warm DEP). Add remaining ingredients at room temperature. Stir 10 minutes. Cool to ambient. Filter through 1-micron filter. Fill into roller-ball dabbas. Shake before use. Longevity: 8–12 hours on skin. Target: Pakistani daily-use attar buyers, Eid gifting, mosques, Gulf export.
Amber Mystic  ·  عنبر مستیک
Oriental Masculine EDP Compound · DEP as fixative co-carrier · 100g compound · Perfume Premix base · Gulf-export / professional male 25–45
DEP — Diethyl Phthalate (≥99.5%)20.00g  20%
Iso E Super (pure)20.00g  20%
Benzyl Benzoate (pure)15.00g  15%
Cedramber (pure)15.00g  15%
Linalool (pure)7.00g  7%
Coumarin (pure — pre-dissolve in DEP)5.00g  5%
Tonalide 10% in DPG8.00g  8%
Beta Damascone 10% in DPG2.00g  2%
DPG — balance (co-solvent)8.00g  8%
Finished Bottle — Perfume Premix Only
Pre-dissolve coumarin in DEP (gentle stir at 30°C). Then add all other ingredients at room temperature and blend 15 min. Filter 1 micron. EDP: 20g compound + 80g Perfume Premix  ·  EDT: 15g + 85g  ·  Parfum: 28g + 72g. Mature 4–6 weeks sealed, cool, dark. Note: DEP at 20% in compound gives exceptional Iso E Super smoothing — the cedar-amber note becomes diffuse and sophisticated rather than sharp. Longevity EDP: 8–12 hours. Gulf-export positioning: warm woody oriental.
Khushbu Agarbatti  ·  خوشبو اگربتی
Traditional Incense Soaking Oil · 100g soaking compound · Use undiluted for bamboo sticks or bakhoor wood · Mosques, homes, events
DEP — Diethyl Phthalate (≥99.5%)70.00g  70%
Iso E Super (pure)10.00g  10%
Benzyl Benzoate (pure)8.00g  8%
Guaiacwood Essential Oil5.00g  5%
Coumarin (pure — pre-dissolve)3.00g  3%
Isoamyl Salicylate (pure)2.00g  2%
Cedryl Acetate (pure)2.00g  2%
Agarbatti Manufacturing Method
1. Warm DEP to 35°C. 2. Pre-dissolve coumarin in warm DEP (5 min). 3. Add remaining ingredients at room temperature; mix 15 min. 4. Filter 100-micron. 5. Fill into soaking tray. 6. Submerge bamboo sticks or charcoal/wood chips 2–4 hours. 7. Drain; dry at room temperature 24–48 hours. Character: authentic bakhoor-style cedar-smoke-sweet. Longevity on burning charcoal: 30–60 min per stick. DEP ensures uniform penetration of wood fibres and locks the fragrance blend until burning releases it.
Formulation Synergies

Classic Pairings

DEP is chemically compatible with virtually all standard fragrance materials and the following pairings represent the most commercially proven and technically validated combinations for Pakistani formulation. Unlike aroma chemical pairings (which create olfactory synergies), DEP pairings are functional: each pairing solves a specific formulation problem while enabling better olfactory performance of the partner material.

Attar Base Formulation
Rose Wardia · 5–15% in DEP base → Classic Gulab Attar backbone Benzyl Benzoate · 5–10% + 15% DEP → Dual fixative attar base DPG · DEP/DPG blended → Polarity tuning for mixed formulas PEA · 5% in 78% DEP → Fresh rose attar; clear, long-lasting
Musk & Fixative Solubilisation
Tonalide · 2–5% dissolved in 20% DEP → Full musk clarity, no haze Galaxolide · 1.5–3% in DEP compound → Polycyclic musk at full potential Coumarin · 5–15% dissolved in DEP → No-heat dissolution; oriental warmth Ethylene Brassylate · 2–3% in DEP → Macrocyclic musk longevity base
Oriental Compound Building
Iso E Super · 15–20% + 20% DEP → Cedar-ambergris smoothed; DEP tames sharpness Benzyl Benzoate · 10% + 10% DEP → Dual-fixative oriental base; South Asian classic Sandalwood EO · 5–10% in DEP → Smooth sandalwood-base attar Patchouli EO · 3–8% in DEP → Earthy-dark oriental; DEP extends earthy depth
Agarbatti & Bakhoor Applications
Guaiacwood EO · 5% in 70% DEP → Authentic smoke-wood incense character Cedarwood EO · 5–10% in DEP → Classic cedarwood bakhoor base Frankincense EO · 3–8% in DEP → Sacred resinous-wood incense accord Perfume Premix · Sole alcohol base for all spray formats
Carrier Solvent Comparison

DEP vs. Alternatives

DPG — Dipropylene Glycol
Glycol Ether · LogP 0.59 · Polar Carrier · Phthalate-Free
Solvency vs. DEP
More polar than DEP (LogP 0.59 vs. 2.47). Excellent for polar aroma chemicals; limited for non-polar musks and nitromusks. Haze risk with high polycyclic musk loading
IFRA / Allergen / Label
✓ IFRA unrestricted · "Phthalate-free" label claim possible · No mandatory allergen declaration · Preferred for EU export natural positioning
Pakistan Application
Recommended when "phthalate-free" labelling required for EU/US markets. Lower solvency range than DEP — may require Polysorbate 20 for musk clarity
Cost / Availability
Similar price to DEP at Bio Shop™. Preferred DPG alternative for phthalate-free positioning. Density: 1.023 g/cm³ (easy to distinguish from DEP)
Verdict: Best phthalate-free alternative for most applications. Choose DPG when "phthalate-free" labelling is needed or for children's/oral-adjacent products. DEP offers broader solvency and superior musk solubilisation. Available at bioshop.pk/products/dpg-dipropylene-glycol
TEC — Triethyl Citrate
Citrate Ester · LogP 0.24 · Biodegradable · FEMA GRAS
Solvency vs. DEP
Very polar (LogP 0.24) — limited compatibility with non-polar fragrance materials. Better suited for hydrophilic applications and lip/oral products
IFRA / Allergen / Label
✓ IFRA unrestricted · FEMA GRAS (safe for oral/lip contact) · Phthalate-free · Biodegradable · Ideal for natural positioning
Pakistan Application
Ideal DEP replacement specifically for oral-adjacent products (lip balm, lip gloss) where DEP's bitter taste is a concern. Limited use in traditional attar formulation
Cost / Availability
Higher cost than DEP or DPG. Emerging use in clean-beauty and oral-safe cosmetics. Not suitable as DEP replacement in high-musk or non-polar attar systems
Verdict: Specific-use alternative for oral/lip products and natural-label clean beauty. Not a general-purpose DEP substitute — solvency range too polar. Choose TEC only when oral-safe biodegradable carrier is specifically required.
IPM — Isopropyl Myristate
Fatty Acid Ester · LogP 7.25 · Non-polar · Skin-Conditioning
Solvency vs. DEP
Very non-polar (LogP 7.25) — excellent for oils and non-polar materials, poor for polar aroma chemicals. Phase separation risk with polar musks at high loading
IFRA / Allergen / Label
✓ IFRA unrestricted · Phthalate-free · Skin-conditioning emollient · Commonly used in body oils and cosmetic skin formulations
Pakistan Application
Good carrier for body oil and hair serum applications where skin-conditioning is valued. Less useful for complex mixed-polarity aroma chemical blends typical of Pakistani orientals
Cost / Availability
Moderate cost. Available commercially in Pakistan. Better suited to personal care oil applications than fragrance compound fixative work
Verdict: Demonstrates DEP's unique "middle-polarity" advantage. IPM and DPG together cover DEP's solvency range, but DEP achieves it alone in a single ingredient. Choose IPM for body oil formulations where skin-conditioning is prioritised.
Benzyl Benzoate
Aromatic Ester · LogP 3.97 · Mild Fixative Odour · IFRA Limits Apply
Solvency vs. DEP
Higher LogP than DEP (3.97 vs. 2.47) — more non-polar. Excellent for musks and non-polar materials; less effective for polar ingredients. Has a mild, clean, slightly floral-oriental odour character unlike odourless DEP
IFRA / Allergen / Label
⚠️ IFRA-restricted in some leave-on categories · Listed EU allergen (declaration required >0.001% in leave-on). Phthalate-free. Bio Shop™ stocked
Pakistan Application
DEP + Benzyl Benzoate dual-fixative base is the classic South Asian attar structure. 10% DEP + 10% BB creates a powerful dual-fixative that extends longevity dramatically with added warm oriental depth
Cost / Availability
Similar cost to DEP. Widely available. Best used as a complement to DEP (dual-fixative) rather than a replacement — IFRA limits restrict its use as a primary carrier at high levels
Verdict: The ideal DEP companion, not a replacement. The DEP + Benzyl Benzoate dual-fixative combination is foundational to Pakistani attar craftsmanship. Use together at 10–15% each for maximum longevity and warm oriental depth. Available at bioshop.pk/products/benzyl-benzoate
Safety & Regulations

IFRA & Safety Overview

Educational summary of publicly available regulatory data as of 2024–2026. Always consult the current IFRA Standards (51st Amendment), the ingredient Safety Data Sheet, RIFM Safety Database, and your regulatory advisor before commercial formulation. This document does not constitute regulatory or safety advice.
✅

IFRA 51st Amendment — Not Restricted

Diethyl Phthalate (DEP, CAS 84-66-2) is NOT restricted, prohibited, or subject to category limits under the IFRA 51st Amendment (June 2023). IFRA's position is unequivocal: DEP does not pose known health risks for human health as currently used in fragrance formulations and cosmetic products. RIFM's comprehensive safety assessment confirmed no toxicological endpoints of concern at normal conditions of use. Pakistani formulators may use DEP freely across all 12 IFRA product categories — attars, EDPs, EDTs, personal care, home fragrance, agarbatti — subject only to Good Manufacturing Practice. No back-calculation or category-specific limit is required.

✅

EU Cosmetics Status — NOT Prohibited (DEP ≠ DEHP/DBP)

DEP is NOT listed in EU Cosmetics Regulation EC 1223/2009 Annex II (prohibited substances). The phthalates banned in EU cosmetics are DEHP, DBP, BBP, and DIBP — all longer-chain, higher-molecular-weight compounds classified as CMR (carcinogenic, mutagenic, or reprotoxic). DEP is structurally and toxicologically distinct from these compounds and carries no CMR classification. Some EU-focused brands voluntarily exclude DEP under "phthalate-free" marketing positioning — this is a commercial choice, not a regulatory requirement. Pakistani exporters to the EU must ensure their DEP is fragrance grade (not an adulterated or industrial product containing traces of restricted phthalates) and can legally include it without violating EU cosmetics law.

✅

Pakistan DRAP & Halal — Fully Compliant

No current restriction under Drug Regulatory Authority of Pakistan (DRAP) cosmetics guidelines. DEP is fully permitted for fragrance, attar, and personal care use in the Pakistani domestic market. Halal status is confirmed: DEP is produced by esterification of phthalic anhydride (petrochemical — o-xylene or naphthalene oxidation; no animal involvement) with ethanol (either petroleum-derived or grain-fermented — the ethanol is completely consumed in the esterification and does not persist in the finished product). The catalyst (sulphuric acid) and neutralisation agent (sodium carbonate) are entirely mineral/inorganic. No animal-origin materials, no free ethanol, no fermentation product in finished DEP. JAKIM, ESMA, and Pakistan Halal Authority guidelines consistently classify synthetic organic esters with fully synthetic origins as halal. Bio Shop™ Pakistan can provide manufacturer halal compatibility documentation on request.

🧪

Human Safety Profile — FDA, RIFM, SCCNFP Confirmed

Acute oral LD₅₀ in rats: 7.7–8.6 g/kg — very low acute oral toxicity. Acute dermal LD₅₀ in rats: >11 g/kg — very low acute dermal toxicity. DEP is not a skin irritant, not a skin sensitiser (OECD 406/429), not phototoxic, not mutagenic (Ames assay), not classified as a carcinogen, and not classified as CMR. The US FDA position (2010 survey, current): "DEP does not pose known risks for human health as currently used in cosmetics and fragrances." The EU's SCCNFP conclusion (2002) similarly found the safety profile supports use in cosmetic products with no specific restrictions. Metabolic fate: DEP is rapidly hydrolysed in the body to monoethyl phthalate (MEP) and phthalic acid, both excreted in urine within 24 hours — no bioaccumulation. Note: taste detection threshold ~20 ppm (bitter) — avoid in lip care and oral-adjacent products.

🌊

Environmental — Standard Precautions

DEP is not classified as an environmental hazard under standard conditions of use. It is not persistent, bioaccumulative, or toxic (PBT) under REACH criteria. Unlike higher-molecular-weight phthalates (DEHP, DINP), DEP's short ethyl chains are biodegraded relatively readily in aquatic environments. California Proposition 65 does NOT list DEP (DBP, DEHP, BBP are listed — not DEP). REACH Entry 51/52 (Annex XVII phthalate restriction) covers DEHP, DBP, BBP, DIBP, DINP, DIDP, DNOP — not DEP. Formulators of rinse-off products in Karachi or Lahore should note DEP in sustainability documentation but need not limit use. Dispose of bulk waste responsibly — do not discharge concentrated DEP to drains. At typical consumer product use levels, aquatic load is negligible.

⚠️

Container Warning & Handling Precautions

Critical handling rule: NEVER store DEP in PVC or polystyrene containers — DEP will plasticise these materials, causing the container to deform and the product to become contaminated with polymer breakdown products. Use HDPE, glass, or aluminium only. Flash point 146°C — not flammable under ambient conditions; normal warehouse fire safety applies. Wear gloves and eye protection; avoid prolonged skin contact and inhalation of heated vapours. Eye contact: flush with water 15 minutes. The taste detection threshold of ~20 ppm makes DEP detectable as bitter in oral/lip products — avoid in these formulations. In alkaline systems (cold-process soap, pH >9), DEP will hydrolyse; use DPG or isopropyl myristate for soap fragrance.

Handling & Storage

Storing in Pakistan's Climate

Temperature
Store below 30°C ideally. DEP remains liquid above −40°C so cold is no concern. Sustained temperatures above 40°C accelerate hydrolysis (rising acid value). Air-conditioned storage preferred for bulk material
Container Type
HDPE drums, glass bottles, or aluminium cans ONLY. NEVER polystyrene or PVC — DEP plasticises and leaches through these materials, causing container failure and product contamination. This is a critical safety rule
Light Exposure
UV-opaque containers preferred. DEP's benzene ring can undergo slow photooxidation under prolonged UV exposure. Avoid direct sunlight on rooftop or open-courtyard storage — particularly relevant in Karachi and Lahore where sunlight is intense year-round
Shelf Life (sealed)
3–5 years from manufacture date at recommended conditions. Check acid value annually for stored bulk material (target ≤0.1 mg KOH/g; reject if above 0.5). Once opened: reseal immediately to prevent moisture ingress
Measuring Technique
DEP is a free-flowing oily liquid at all ambient temperatures — easy to dispense and weigh. Use a 0.01g precision balance for compound-level additions (5–30%). For trace additions below 5%, a standard balance is adequate. No heating required for most applications
Pre-Use Handling
DEP is used pure — it is the solvent itself, not something that needs dissolving. For solid ingredients (coumarin, ethyl vanillin, musk ketone): warm DEP to 30–35°C and dissolve solids in the DEP portion first, then cool to ambient before adding other ingredients
Lahore Summer (May–Sep)
Temperatures 38–45°C. Primary concern: accelerated hydrolysis if moisture enters container. Store in air-conditioned space or cool shaded warehouse. Never leave bulk DEP in vehicles in summer heat. Dust-free storage important — particulates can catalyse surface reactions in open containers
Karachi Coastal Climate
High humidity (75–90% RH year-round, higher in monsoon). Moisture ingress is the primary degradation driver. Reseal HDPE drums immediately after dispensing. Use desiccant-filled vent caps on drums opened regularly. Check containers for internal condensation periodically. Acid value monitoring every 6 months for stored bulk
⚠ Quality verification: Fragrance-grade DEP is water-white, clear, and oily with essentially no odour. Density: 1.118–1.122 g/cm³ at 20°C — weigh 10 mL; should read 11.18–11.22g. Readings below 11.00g indicate dilution with lighter solvents (DPG: 1.023; mineral oil: ~0.85). Clarity test: 5 mL against backlight should be fully clear, no haze or cloudiness. Solubility test: dissolve 0.1g Coumarin in 5 mL sample — fragrance-grade DEP dissolves it readily at room temperature; inferior grades leave undissolved residue. Acid value: ≤0.1 mg KOH/g (fragrance grade); above 0.5 = degraded or adulterated. Always request a GC certificate of analysis with specific batch number from any supplier.
FAQs

Frequently Asked Questions

Is DEP halal? Can I use it in attar formulations for Muslim consumers?+
DEP is halal. The complete synthesis chain: (1) Phthalic anhydride — manufactured by catalytic gas-phase oxidation of ortho-xylene or naphthalene (both petroleum-derived aromatic hydrocarbons); no animal involvement at any stage. (2) Ethanol — used as a reagent in esterification, fully chemically transformed into the ethyl ester group within the DEP molecule. Even if the ethanol feedstock is grain-fermented rather than petroleum-derived (both are used commercially), the ethanol is completely consumed in the chemical reaction and no ethanol — free, bound, or residual — remains in the finished DEP product. The finished ester contains no free ethanol and no phthalic acid above the specification limit. (3) Catalyst: sulphuric acid (mineral acid, fully inorganic). Neutralisation: sodium carbonate (mineral/inorganic). No animal-origin materials appear at any stage of synthesis. Islamic scholars and halal certification bodies including JAKIM, ESMA, and the Pakistan Halal Authority consistently classify synthetic organic esters with fully synthetic, non-animal origins as halal. DEP qualifies clearly under this classification. Bio Shop™ Pakistan can provide manufacturer halal compatibility documentation on request for professional accounts. DEP is the traditional base for South Asian Islamic attar tradition — its use in attar is itself a mark of its halal acceptability.
How can I verify the purity of DEP I purchase in Pakistan?+
Four practical field verification methods are available without laboratory GC equipment. First, the density test: weigh 10 mL of sample in a tared glass vessel. Fragrance-grade DEP should read 11.18–11.22 grams (density 1.118–1.122 g/cm³). Readings below 11.00g indicate dilution with lighter solvents — DPG reads only ~10.23g per 10 mL, and mineral oil approximately 8.5g. This simple test immediately reveals any significant dilution. Second, the clarity test: pour 5 mL into a clear glass bottle and hold against a bright light or white background. Fragrance-grade DEP is completely water-white and clear with no haze, cloudiness, or colour. Any turbidity indicates mineral oil or fatty acid contamination. Third, the solubility test: dissolve 0.1g of Coumarin powder in 5 mL of sample at room temperature. Genuine fragrance-grade DEP dissolves Coumarin readily without heating; inferior or adulterated material may show undissolved residue. Fourth, the odour test: apply one small drop to an unscented white blotter. Fragrance-grade DEP has essentially no odour — it should read as blank, with no chemical, plastic, or solvent background. Any detectable odour indicates below-specification material. Always request a batch-specific GC certificate of analysis with acid value, density, and colour (APHA) data from any supplier. Bio Shop™ Pakistan provides this documentation with every delivery.
How should I store DEP in Pakistan's hot and humid climate?+
The primary storage concern for DEP in Pakistan is moisture ingress, which drives hydrolysis (rising acid value over time) — not heat per se, since DEP's ester bonds are thermally stable to 100°C under dry conditions. For Lahore's extreme summer heat (38–45°C): maintain air-conditioned or shaded, cool storage; never leave bulk containers in vehicles during summer; transfer to smaller containers to reduce headspace if drums are partially depleted. For Karachi's coastal humidity (75–90% RH, higher in monsoon): always reseal containers immediately after dispensing; use desiccant-filled vent caps on drums opened regularly; check containers for internal condensation periodically. For both locations: use sealed HDPE drums, glass bottles, or aluminium cans exclusively — NEVER polystyrene or PVC (DEP plasticises both). Store away from direct UV light. Check acid value every 6 months for stored bulk material (target ≤0.1 mg KOH/g; reject if above 0.5). Under these conditions, a sealed drum of fragrance-grade DEP will meet specification for 3–5 years. Opened containers: reseal discipline is the single most important practice for maintaining quality.
Is DEP safe? I have heard about the "phthalate controversy" and am confused.+
DEP's safety for fragrance use is well established by four independent major regulatory bodies: IFRA (not restricted), FDA (does not pose known risks for human health as currently used), RIFM (no safety concern at normal use levels), and the EU's SCCNFP (safety profile supports use in cosmetic products). The "phthalate controversy" centres on DEHP (di-2-ethylhexyl phthalate), DBP (dibutyl phthalate), BBP (benzyl butyl phthalate), and DIBP — longer-chain phthalates that have been established as reproductive toxicants (classified as CMR) and are now prohibited in EU cosmetics. DEP is structurally and toxicologically fundamentally different from these compounds: its short ethyl chains (C2) are rapidly hydrolysed and metabolically cleared in mammals within 24 hours, leaving no accumulation, no demonstrated endocrine disruption at normal use levels, and no reproductive concern. DEP is NOT classified as CMR, NOT listed under California Proposition 65, and NOT an SVHC under REACH. The practical decision to switch to DPG should be based on market requirements (phthalate-free labelling for EU or premium US retail), product type (children's products and lip care are better served by DPG or TEC), and consumer communication strategy — not on a regulatory safety concern that does not apply to DEP.
What is the correct usage level of DEP? Should I use it pure or diluted?+
DEP is always used pure — it IS the solvent and carrier, not an ingredient that needs to be dissolved. Unlike aroma chemicals offered in 10% DPG dilution for precision measuring, DEP is the diluent itself. Usage levels depend entirely on the application: as an attar base oil, DEP typically comprises 60–90% of the total formula weight, with the fragrance blend making up the remainder. As a fixative and co-solvent in a fragrance compound for EDP/EDT production, DEP is used at 5–20% of the compound weight. As an agarbatti soaking oil, DEP may be 70–95% of the total, with fragrance compound at 5–30%. For first-time formulators, start with 15% DEP in your fragrance compound and evaluate longevity improvement after a 72-hour maceration; increase to 25–30% if more longevity is needed. There is no olfactory "overdose" concern since DEP has no meaningful aroma — the only upper limit in attar is cost-in-use (DEP is very affordable, but every gram displaces a gram of fragrant material) and in compound formulation, ensuring the finished fragrance has sufficient concentration of aroma chemicals to perform at the desired strength. Key formula rule: in EDP/EDT finished bottles, Perfume Premix is the sole alcohol base — DEP remains in the compound phase only.
Does DEP require allergen declaration for EU export products?+
For Pakistan domestic market: no restrictions or labelling requirements for DEP. For EU or UK export: DEP is NOT listed under EU Cosmetics Regulation 1223/2009 Annex III as a mandatory declarable fragrance allergen. It has no sensitisation classification under RIFM assessment. This means Pakistani manufacturers exporting to the EU can include DEP in formulations without triggering mandatory allergen declarations specifically for DEP. However, two important distinctions apply. First, some EU retailers and brands voluntarily require "phthalate-free" formulations as a supplier requirement — check your specific customer's code of practice before assuming regulatory permission translates to commercial acceptance. Second, DEP itself may not trigger a declaration, but if your formula also contains regulated allergens (Linalool, Geraniol, Citronellol, etc.) at declarable levels, those must still be declared — DEP does not affect this calculation. For US FDA compliance: DEP is acceptable in cosmetics per FDA position. For California Prop 65: DEP is not listed (DBP and DEHP are listed — not DEP). Monitor regulatory updates through IFRA or an EU regulatory consultant, as requirements can change.
Which Pakistani consumer segments respond best to DEP-based products?+
Four segments respond most strongly. First and most importantly, the attar market — consumers who value oil-based, alcohol-free fragrances for daily use, religious observance (particularly for prayers, where alcohol-based fragrance is traditionally avoided), and gifting. This segment spans all socioeconomic groups in Pakistan, from bazaar attar buyers in Lahore's Anarkali market to professional urban consumers in Karachi and Islamabad. DEP-based attars are experienced as long-lasting, smooth, and premium by this segment — without consumers knowing DEP is the ingredient responsible for these qualities. Second, Gulf Pakistani diaspora and export buyers: DEP-based attars are familiar, traditional, and highly regarded in Saudi Arabia, UAE, Qatar, and Bahrain. Gulf buyers specifically associate the smooth, long-lasting quality of DEP-based attars with South Asian attar craftsmanship. Third, the agarbatti and bakhoor segment, which spans all household demographics — DEP-based incense oils are used in mosques, homes, and events across Pakistan without segment limitation. Fourth, personal care formulators targeting daily-use body oil, hair serum, and roll-on fragrance products for the domestic mass market, where DEP's very low cost enables premium fragrance loading at accessible retail price points.
What Urdu names work for DEP-based products? How does DEP perform in Pakistan's summer heat?+
For Urdu marketing, focus on the fragrance character and the longevity benefit rather than the carrier — consumers buy the scent, not the solvent. Effective naming and tagline concepts: شیریں خوشبو (Sheerin Khushbu — Sweet Fragrance), مہکتی عطر (Mehakti Itr — Fragrant Attar), دیر تک مہکنا (Deer Tak Mehkna — Long-Lasting Scent) as a product tagline — this phrase directly communicates DEP's primary consumer benefit. Specific composition names from the Bio Shop™ reference: شیریں گلاب (Sheerin Gulab — Sweet Rose, for rose attar), عنبر مستیک (Amber Mystic, for oriental masculine EDP), خوشبو اگربتی (Khushbu Agarbatti, for incense oil), شمس کی خوشبو (Shams Ki Khushbu — Sun's Fragrance, for summer attar). Hot weather performance is one of DEP's genuine competitive advantages in Pakistan: in Lahore or Karachi summer at 40–45°C, alcohol-based fragrances "blast and fade" — the high evaporation rate gives a brief intense opening but very short longevity. A DEP-based roll-on attar on the same skin will release fragrance steadily and measurably for many hours more, precisely because DEP's high boiling point (298°C) and very low vapour pressure (0.002 mmHg) mean it does not depart the skin surface — and it holds the aroma chemicals within it for gradual, sustained release throughout the day.
Complete Your Palette

Essential Companions

Carrier · Phthalate-Free Alternative
Dipropylene Glycol (DPG)
Primary phthalate-free alternative carrier · Blend DEP/DPG for polarity tuning · "Phthalate-free" label claim possible
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Alcohol Base
Perfume Premix
Sole alcohol base for EDP/EDT spray formulas · Works alongside DEP in compound phase · Bio Shop™ exclusive
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Co-Fixative · Aromatic Ester
Benzyl Benzoate
Classic dual-fixative base: 10% DEP + 10% BB → the South Asian attar foundation. Oriental depth + maximum longevity
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Aroma Chemical · Solid
Coumarin
DEP dissolves coumarin at 15–20% at room temperature — no heating. Essential oriental warmth; sweet hay-tonka character
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Aroma Chemical · Rose
Rose Wardia
5–15% Rose Wardia in 78% DEP = the backbone of Pakistan's commercial gulab attar. DEP accepts it without polarity mismatch
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Aroma Chemical · Woody
Iso E Super
DEP + Iso E Super: 20% DEP tames ISO E Super's sharp blast, delivering cedar-ambergris as a smooth, diffuse woody cloud
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Aroma Chemical · Musk
Galaxolide
Polycyclic musks dissolve better in DEP than DPG — enabling richer, clearer musk bases for Pakistani orientals and body sprays
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Essential Oil · Resinous
Frankincense EO
3–8% Frankincense in DEP base → sacred resinous-wood bakhoor accord. DEP extracts and carries the full sesquiterpene complexity
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Full Reference Document

Dive Deeper — Read the Complete Guide

Everything on this page and substantially more — the complete two-stage industrial synthesis mechanism of DEP from phthalic anhydride and ethanol with detailed reaction conditions and purification steps, the full molecular structure-solubility relationship analysis explaining DEP's unique mid-polarity advantage over DPG and IPM, complete RIFM safety assessment data with acute and chronic toxicological endpoints, a historical survey of landmark 20th-century fragrances in which DEP served as the invisible structural foundation (Chanel No. 5, Shalimar, Joy, Arpege, Youth Dew, Brut), Raoult's Law derivation showing the quantitative vapour pressure depression effect at different DEP concentrations, compatibility tables for 20+ fragrance materials, advanced blending strategies including DEP/coumarin, DEP/musk, DEP/Iso E Super, DEP/benzyl benzoate pairings, three complete production formulas (Sheerin Gulab attar, Amber Mystic EDP, Khushbu Agarbatti), Pakistan climate stability testing protocol with acid value monitoring schedule, and a 20-term glossary of DEP chemistry and perfumery terminology — all in one complete professional reference document.

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