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| Synonyms:DEP Phthalic acid diethyl ester Diethyl benzene-1,2-dicarboxylate Diethyl phthalate fragrance grade Molecular Formula:C12H14O4 Molecular Weight: 222.24 HS Code: 2917349000 Grade: Industrial grade 98% Hazard Class:General Cargo | |||||||||
84-66-2
bosschem
84-66-2
Diethyl phthalate (DEP; diethyl benzene-1,2-dicarboxylate; C₆H₄(COOC₂H₅)₂, CAS 84-66-2) is the short-chain diethyl ester of phthalic acid — a clear, colorless, practically odorless oily liquid with very low volatility. It is the classic low-molecular-weight phthalate for cellulose esters: the plasticizer behind cellulose-acetate film, tape, eyewear frames and nitrocellulose lacquers, and simultaneously a fragrance fixative and solvent, an alcohol denaturant. This page covers its identity, properties, applications, packaging and supply details.
Core value propositions:
● The Cellulose-Ester Plasticizer (Core Application): 10–25% loadings in cellulose-acetate film, tape and eyewear frames;
● Fragrance-Grade Versatility: fixative, blender and solvent for perfumes and cosmetic ingredients;
Item | Specification |
Chemical Name | Diethyl phthalate (diethyl benzene-1,2-dicarboxylate) |
Synonyms | Ethyl phthalate; phthalic acid diethyl ester; DEP; Palatinol A; Kodaflex DEP; Unimoll DA; Placidol E |
CAS No. | 84-66-2 |
EC No. (EINECS) | 201-550-6 |
Molecular Formula | C₁₂H₁₄O₄ (C₆H₄(COOC₂H₅)₂) |
Molecular Weight | 222.24 g/mol |
Appearance | Clear, colorless, practically odorless oily liquid (bitter disagreeable taste) |
Solubility | Sparingly soluble in water (≈ 1.08 g/L at 25 °C); miscible with most organic solvents and oils |
Diethyl phthalate is produced by esterification of phthalic anhydride with ethanol under strong acid catalysis. The molecule pairs a rigid aromatic ring with two short ethyl ester arms — a compact, polar structure that makes it an outstanding solvent and softening agent for cellulose esters and many other polymers, while its moderate molecular weight keeps volatility very low for its size. The short ethyl chains also give DEP the highest water tolerance and the best solvency of the common phthalates, which is why it performs as a coupling solvent and fixative rather than as a general-purpose PVC plasticizer. It melts near -40 °C, stays fluid in cold service, sinks in water and is readily degraded by microorganisms in soil and water.
● Best-in-class cellulose solvency: plasticizes cellulose acetate, nitrocellulose, cellulose acetate butyrate and other cellulose derivatives.
● Dual role in fragrance: dissolves fragrance oils and slows their evaporation (fixative) — the standard vehicle for fragrance and cosmetic ingredients.
● Broad polymer compatibility: polystyrene, PMMA, PVAc, PVB and PVC systems.
● Very low volatility and excellent low-temperature fluidity (mp ≈ -40.5 °C).
● Regulatory breadth: food-contact adhesives and packaging; widely used in cosmetics.
DEP is the traditional plasticizer for cellulose acetate at 10–25% by weight. Its specific working point: the small polar ester groups insert between the stiff cellulose chains and disrupt their hydrogen-bonded packing, converting brittle film into flexible, workable material — the same effect that makes it the plasticizer in cellulose-acetate adhesive tape, photographic and packaging film, eyewear frames and biodegradable plastics, and a softener for nitrocellulose lacquers, varnishes and dopes in celluloid manufacture.
● Cellulose-acetate film, tape and sheets: flexibility and toughness.
● Eyewear frames and molded cellulose plastics.
● Nitrocellulose lacquers, varnishes and dopes: film flexibility and adhesion.
DEP is the classic vehicle for fragrance and cosmetic ingredients. Its specific working points: it dissolves perfume oils and blends them evenly, and its very low volatility slows the evaporation of the lighter top notes, prolonging fragrance life; as a cosmetic carrier it provides stable, non-reactive dilution of actives. The same solvency makes it a standard denaturant in specially denatured alcohol formulations.
● Perfume and cologne: blender and fixative.
● Cosmetic and personal-care formulations: vehicle for fragrance and active ingredients.
● Alcohol denaturant for specially denatured alcohol.
Beyond cellulose, DEP is a compatible plasticizer and wetting agent for polystyrene, polymethyl methacrylate (PMMA), polyvinyl acetate (PVAc), polyvinyl butyral (PVB) and PVC. Its specific working point: in these systems it acts as a processing aid that lowers melt viscosity and improves wetting of fillers and pigments, and at higher loadings it imparts flexibility; its compact size and polarity suit shorter-chain and higher-glass-transition polymers better than long-chain phthalates.
● Polystyrene, PMMA and PVAc compounds: plasticizer and processing aid.
● PVB and PVC formulations: flexibility and wetting.
● Wetting agent for pigments, fillers and resin systems.
DEP is used as a plasticizer/desensitizer in solid rocket propellants, including double-base propellants with high nitroglycerin content, and in ammonium perchlorate composite propellants where it tunes viscosity and energy balance. Its specific working point in energetic formulations: the ester moderates the mechanical sensitivity of nitrocellulose–nitroglycerin matrices while improving low-temperature processability. It was also used historically as an insect and mosquito repellent.
● Double-base and composite solid propellants: plasticizer and desensitizer.
● Viscosity and process control in energetic formulations.
● Former insect/mosquito repellent use.
Packaging (customizable):
● 200 kg steel drums; 1,000 kg IBC totes; ISO tank or bulk road tanker for large orders; small packs on request;
Storage:
● Store in a cool, dry, well-ventilated area; keep containers tightly closed;
● Avoid prolonged high temperature and direct sunlight (flash point ≈ 140 °C);
● Keep away from strong oxidizing agents; prevent release to waterways — DEP may be hazardous to aquatic life (fish).
● Factory-direct supply: own production and sourcing capability, transparent pricing, no middleman markup.
● Stable quality: strict internal control, every batch tested (assay, acid value, water content), COA with every shipment.
● Fast response: quotations and technical support (COA, SDS, application advice); small trial orders accepted.
DEP is primarily the plasticizer for cellulose acetate (film, tape, eyewear frames, biodegradable plastics, nitrocellulose lacquers), the fixative and solvent in perfumes and cosmetics, an alcohol denaturant, a compatible plasticizer for polystyrene, PMMA, PVAc, PVB and PVC, a plasticizer in solid propellants
Because it is a nearly odorless, very low-volatility solvent for fragrance oils: it dissolves the perfume concentrate for even blending and slows the evaporation of the volatile top notes, so the scent lasts longer — the classic fixative function. The same inertness and solvency make it a standard vehicle for diluting cosmetic and fragrance ingredients without altering their character.
DEP is the short-chain diethyl ester — a light, water-tolerant solvent/fixative and cellulose plasticizer with a mild toxicological profile. DEHP (di-2-ethylhexyl phthalate) and DBP (dibutyl phthalate) are the long-chain general-purpose PVC plasticizers that carry reproductive-toxicity (CMR) classifications and are heavily restricted in toys, cosmetics and consumer products.
