Dioctyl Maleate, DOM, 142-16-5

DIOCTYL MALEATE (DOM) 

Chemical Name: Dioctyl Maleate (DOM)
CAS Number: 142-16-5
Molecular Formula: C₂₀H₃₆O₄
Molecular Weight: ~340 g/mol
Chemical Class: Plasticizer, diester, organic compound

SECTION 1: PRODUCT IDENTIFICATION AND CHEMICAL IDENTITY

PRODUCT DESCRIPTION AND EXPLANATION:

Dioctyl Maleate (DOM) is a diester compound obtained by the esterification reaction of maleic acid with 2-ethylhexanol (octyl alcohol). It is a colorless to light yellow, low-viscosity liquid with a mild ester odor. DOM is an industrial chemical widely used as a plasticizer, especially in PVC (polyvinyl chloride) and acrylic copolymers.

The double bond present in its molecular structure (maleate group) is an important feature that distinguishes DOM from other plasticizers. This double bond allows DOM to participate in copolymerization reactions and chemically bond to the polymer chain. This property places DOM in the class of "reactive plasticizers" or "copolymerizable plasticizers." As a result, DOM chemically bonds to the polymer matrix, showing lower migration and volatilization tendencies compared to conventional plasticizers.

DOM can be used both as a primary plasticizer and as a co-plasticizer together with other plasticizers. Additionally, it has various applications as an intermediate in the production of surfactants and in the coatings and adhesives industries. It is insoluble in water, but readily soluble in organic solvents.

SECTION 2: PHYSICAL AND CHEMICAL PROPERTIES

SOLUBILITY PROFILE:

PHYSICAL AND CHEMICAL PROPERTIES EXPLANATION:

Dioctyl Maleate is a colorless to light yellow, clear and homogeneous liquid at room temperature. It has a mild ester odor that is characteristic but not unpleasant. Its density is ~0.91 g/cm³, making it lighter than water. It has a high boiling point (>200°C) and exhibits low volatility (vapor pressure <0.01 mmHg at 20°C). The flash point is ~185°C, which is critical for assessing flammability risk.

Viscosity is low (~12-15 cP at 20°C), indicating that DOM is an easily processable liquid. The melting point is ~ -50°C, meaning it remains liquid even at very low temperatures. The refractive index is ~1.452.

Solubility profile: DOM is insoluble in water but readily soluble in organic solvents such as acetone, ethanol, toluene, xylene, mineral oils, ester and ketone solvents. It has limited solubility in aliphatic hydrocarbons. This solubility profile enables easy integration of DOM into polymer systems.

SECTION 3: CHEMICAL PROPERTIES AND REACTIONS

CHEMICAL PROPERTIES EXPLANATION:

Dioctyl Maleate is a diester compound containing two ester groups (-COOR) and a double bond (C=C) in its molecular structure. This double bond is DOM's most important chemical property; it enables participation in polymerization and copolymerization reactions. Thus, DOM can function as a "reactive plasticizer" by chemically bonding to the polymer chain.

Hydrolysis sensitivity: Under acidic or basic conditions, DOM can hydrolyze to form maleic acid and 2-ethylhexanol (octyl alcohol). Therefore, it should be protected from moisture and acid/base contamination.

Polymerization reactions: Due to the double bond in the maleate group, DOM can participate in copolymerization with styrene, vinyl acetate, acrylates, methacrylates and other vinyl monomers in the presence of radical initiators. This property makes DOM a valuable intermediate in polymer modification.

Thermal decomposition: Above 200°C, DOM begins to decompose, releasing CO₂, CO and various hydrocarbons. Processing temperatures should be kept below this value.

Oxidation sensitivity: Compounds containing double bonds are sensitive to oxidation. Oxidation products may form during long-term storage or at high temperatures; therefore, antioxidants may be added or storage under inert atmosphere may be recommended.

SECTION 4: FUNCTIONAL PROPERTIES

FUNCTIONAL PROPERTIES EXPLANATION:

Dioctyl Maleate shows high efficiency as a plasticizer in PVC and acrylic copolymers. By incorporating into the polymer chain (copolymerization) or physically mixing, it increases polymer flexibility, lowers the glass transition temperature, and provides flexibility at low temperatures.

DOM's most important functional property is its ability to function as a "reactive plasticizer." Due to the double bond in the maleate group, DOM can participate in polymerization reactions and chemically bond to the polymer chain. This property gives DOM much lower migration and volatilization tendencies compared to conventional plasticizers (e.g., DOP - Dioctyl Phthalate). This feature is a significant advantage in applications where migration is critical, such as food contact, medical devices, and automotive interior applications.

DOM has low volatility (high boiling point, low vapor pressure), which minimizes volatilization losses during processing and maintains long-term plasticizing effectiveness. It is also compatible with other primary and secondary plasticizers and can be used together with them.

SECTION 5: APPLICATION AREAS AND INDUSTRIAL USES

5.1. Plasticizer (Primary Application)

5.2. Coatings and Adhesives Industry

5.3. Surfactant Production

5.4. Polymer Modification

APPLICATION AREAS EXPLANATION:

Plasticizer (Primary Application):

The most common use of Dioctyl Maleate is as a PVC (polyvinyl chloride) plasticizer. DOM imparts the following properties to PVC:

• Flexibility: Increases mobility of polymer chains, making the material flexible.

• Low Temperature Resistance: Maintains flexibility even at low temperatures.

• Processability: Improves melt flow properties, facilitates extrusion and injection molding processes.

DOM's use as a "reactive plasticizer" provides a major advantage in applications where migration is critical (food packaging, medical devices, automotive interior). Since it chemically bonds to the polymer chain, volatilization or migration of DOM from the product to contact surfaces is minimized.

Coatings and Adhesives Industry:

In coating formulations, DOM improves flexibility, adhesion and film properties. In adhesives, it increases flexibility and adhesion strength. In printing inks, it is used as a plasticizer, especially in flexible packaging printing.

Surfactant Production:

DOM is used as an intermediate in the production of surfactants through sulfonation or sulfation reactions. Particularly, it is an important intermediate in the synthesis of sulfosuccinate type surfactants (e.g., dioctyl sulfosuccinate) through reaction of the maleate group with sulfite.

Polymer Modification:

DOM's double bond makes it suitable for copolymerization reactions with styrene, vinyl acetate, acrylates, methacrylates and other vinyl monomers. Thus, it can be used as a monomer in the synthesis of polymers with special properties.

SECTION 6: ADVANTAGES

• Reactive Plasticizer: Can chemically bond to polymer chain; minimizes migration, exudation and volatilization issues.

• Low Volatility: High boiling point and low vapor pressure minimize loss during processing.

• Low Temperature Resistance: Imparts flexibility and durability to polymers at low temperatures.

• Excellent Compatibility with PVC: Shows good compatibility with PVC; provides homogeneous distribution.

• Compatibility with Other Plasticizers: Can be used together with various primary and secondary plasticizers.

• Copolymerization Capability: Copolymerization with styrene, vinyl acetate, acrylates and methacrylates; provides flexibility in polymer design.

• Surfactant Intermediate: Important intermediate in the synthesis of sulfosuccinate type surfactants.

• Low Toxicity: Lower toxicity profile compared to some older plasticizers such as dioctyl phthalate (DOP).

• Color Stability: Light yellow color suitable for applications with color sensitivity.

SECTION 7: QUALITY STANDARDS AND SPECIFICATIONS

QUALITY STANDARDS EXPLANATION:

Dioctyl Maleate is manufactured according to industrial quality standards. Purity (by GC) should be ≥98.0%. Acid number ≤0.5 mg KOH/g indicates low free acid content. Water content (by Karl Fischer titration) is limited to ≤0.1%; high water content can cause hydrolysis and quality degradation. Color (APHA/Pt-Co scale) ≤50 guarantees colorless or very light yellow color quality. Ester content ≥98.0% indicates high purity and quality.

SECTION 8: SAFETY AND TOXICOLOGY

SAFETY AND TOXICOLOGY EXPLANATION:

Dioctyl Maleate is a chemical with moderate toxicity. Oral LD50 (rat) is in the range of ~3000-5000 mg/kg. May cause mild skin irritation and mild to moderate eye irritation. No mutagenic, carcinogenic or reproductive toxicity classification.

Safety Precautions:

• Inhalation: Avoid inhalation of vapors. Provide adequate ventilation.

• Skin Contact: Wash with plenty of water and soap upon skin contact.

• Eye Contact: Rinse with plenty of water for at least 15 minutes upon eye contact. Remove contact lenses if present.

• Ingestion: Rinse mouth with water. Do not induce vomiting. Seek medical attention if large amount is swallowed.

• PPE Recommendations: Chemical safety goggles, chemical resistant gloves (nitrile/neoprene), protective clothing and appropriate respiratory protection.

• Ventilation: Use in well-ventilated areas; local exhaust ventilation recommended.

SECTION 9: TRANSPORT INFORMATION

TRANSPORT INFORMATION EXPLANATION:

Dioctyl Maleate is subject to hazardous material transport. UN number is 3082 and classified as "Environmentally Hazardous Substance, Liquid, N.O.S." ADR/RID hazard class is 9 (Environmentally Hazardous Substances), packing group III. Classified as a marine pollutant (IMDG). During transport, precautions against leakage should be taken, good ventilation provided, and kept away from heat sources. Additionally, necessary measures should be taken to prevent the product from entering the marine environment.

SECTION 10: REGULATORY INFORMATION

REGULATORY INFORMATION EXPLANATION:

Dioctyl Maleate is registered in all major industrial markets including the EU (REACH), USA (TSCA), Canada (DSL), Australia (AICS), Japan (ENCS), Korea (KECL) and China (IECSC). In Türkiye, it requires mandatory registration under KKDİK (Regulation on Registration, Evaluation, Authorization and Restriction of Chemicals). It is classified as a Class 9 hazardous substance under ADR.

SECTION 11: STORAGE AND HANDLING

STORAGE AND HANDLING EXPLANATION:

Dioctyl Maleate should be stored at 15-30°C in cool, dry and well-ventilated areas. It should be kept in tightly closed containers, preferably in original packaging. Protect from moisture, direct sunlight, high temperature and air (oxidation). For long-term storage, storage under inert gas (nitrogen) is recommended to prevent oxidation.

Avoid contact with strong oxidizing agents, strong acids and strong bases. Moisture can cause hydrolysis, leading to increased acid number and decreased product quality. Under proper storage conditions, shelf life is 12-24 months.

Handling Notes:

• Avoid vapor inhalation (good ventilation, local exhaust)

• Avoid skin and eye contact (protective gloves and goggles)

• Do not expose to moisture and water (hydrolysis risk)

• Minimize exposure to air (oxidation risk; use under inert gas)

• Use appropriate absorption materials in case of spillage

SECTION 12: FIRE FIGHTING MEASURES

FIRE FIGHTING MEASURES EXPLANATION:

Dioctyl Maleate is a combustible liquid. In case of fire, use water spray, CO₂, dry chemical powder or alcohol foam for extinguishing. Thermal decomposition may produce CO₂, CO and hydrocarbon fumes. Use self-contained breathing apparatus (SCBA) and full protective clothing during fire fighting. Vapors can form explosive mixtures in air.

SECTION 13: ACCIDENTAL RELEASE MEASURES

ACCIDENTAL RELEASE MEASURES EXPLANATION:

In case of spillage, appropriate personal protective equipment should be worn (chemical safety goggles, chemical resistant gloves, protective clothing). The area should be ventilated and the liquid contained to prevent spread. Cleaning should be done by absorption with absorbent material (sand, diatomite, sawdust), and the spilled material placed in an appropriate disposal container. Environmental release (drains, sewers, water bodies) should be prevented. Waste should be disposed according to local regulations.

SECTION 14: FIRST AID MEASURES

FIRST AID MEASURES EXPLANATION:

Standard first aid measures apply for Dioctyl Maleate exposure:

• Inhalation: In case of vapor inhalation, move the person to fresh air. If breathing difficulty, administer oxygen. If irritation persists, seek medical attention.

• Skin Contact: Liquid should be removed from skin by washing with plenty of water and soap. Remove contaminated clothing. If irritation persists, seek medical attention.

• Eye Contact: Eyes should be rinsed immediately with plenty of water for at least 15 minutes. Remove contact lenses if present. If irritation persists, seek medical attention.

• Ingestion: Rinse mouth with water, drink plenty of water. Do not induce vomiting. If large amount is swallowed, seek medical attention.

SECTION 15: RAW MATERIALS AND DOWNSTREAM PRODUCTS

15.1. Raw Materials (Upstream)

15.2. Downstream Products

SECTION 16: INDUSTRY COMPATIBILITY AND USAGE VOLUMES

SECTION 17: DIOCTYL MALEATE vs DIOCTYL PHTHALATE (DOP) COMPARISON

COMPARISON EXPLANATION:

Dioctyl Maleate and Dioctyl Phthalate (DOP) are two widely used compounds as PVC plasticizers. DOM can function as a reactive plasticizer due to its double bond-containing structure and can chemically bond to the polymer chain. This property significantly reduces DOM's migration and volatilization tendencies compared to DOP.

DOP is more common and less expensive as a general-purpose PVC plasticizer; however, phthalate-class compounds have been restricted in some applications due to health and environmental concerns. DOM is being evaluated as an alternative to DOP in these applications with its lower toxicity profile and better low temperature resistance. DOM also differs from DOP in its use as an intermediate in the synthesis of sulfosuccinate type surfactants.

SECTION 18: DERIVATIVES AND RELATED COMPOUNDS

SECTION 19: SUMMARY AND CRITICAL NOTES

SUMMARY:

Dioctyl Maleate (DOM, CAS 142-16-5) is a diester compound obtained by esterification of maleic acid with 2-ethylhexanol. It is a colorless to light yellow, low-viscosity liquid with a mild ester odor. Molecular weight is ~340 g/mol, density is ~0.91 g/cm³, boiling point is >200°C. Insoluble in water, readily soluble in organic solvents.

The double bond in its molecular structure (maleate group) makes DOM a "reactive plasticizer"; it chemically bonds to the polymer chain, minimizing migration and volatilization issues. The primary use is as a plasticizer in PVC and acrylic copolymers. It is also used in coatings and adhesives industries, as an intermediate in surfactant production, and in polymer modification.

Dioctyl Maleate is classified as ADR Class 9 (Environmentally Hazardous Substance) and is subject to hazardous material transport. UN number is 3082. Store in cool, dry and well-ventilated areas, protected from moisture and oxidation. Shelf life is 12-24 months. Has moderate toxicity; use with appropriate PPE.

Basic Properties:

Main Application Areas:

Key Safety Points:

• HAZARDOUS SUBSTANCE: ADR Class 9; UN 3082; Environmentally Hazardous Substance

• COMBUSTIBLE LIQUID: May ignite at high temperatures; keep away from heat sources

• IRRITANT: May cause skin and eye irritation; use appropriate PPE

• STORAGE: 15-30°C, cool, dry, well-ventilated; protect from moisture and oxidation

• PPE RECOMMENDED: Chemical safety goggles, nitrile/neoprene gloves, protective clothing

• INCOMPATIBLE: Strong oxidizing agents, strong acids, strong bases

• UN NUMBER: 3082

• SHELF LIFE: 12-24 months (under proper storage)

CRITICAL NOTES:

1. Reactive Plasticizer: Dioctyl Maleate can participate in polymerization and copolymerization reactions due to the double bond in the maleate group. This property distinguishes DOM from conventional plasticizers; it chemically bonds to the polymer chain, minimizing migration, exudation and volatilization issues.

2. Low Migration and Volatility: The ability to chemically bond to the polymer chain significantly reduces volatilization or migration of DOM from the product to contact surfaces. This feature provides a major advantage in applications where migration is critical, such as food packaging, medical devices and automotive interior.

3. Excellent Compatibility with PVC: DOM shows excellent compatibility with PVC. It imparts flexibility, low temperature resistance and processability to PVC. Widely used in flexible PVC film, sheet, profile, cable, pipe and hose production.

4. Copolymerization Capability: DOM can participate in copolymerization with styrene, vinyl acetate, acrylates, methacrylates and other vinyl monomers. This property provides flexibility in the design of polymers with special properties.

5. Surfactant Intermediate: DOM is an important intermediate in the synthesis of sulfosuccinate type surfactants (especially Dioctyl Sulfosuccinate - DOSS). DOSS has wide application as a wetting agent, dispersant and emulsifier.

6. Transport Class: DOM is classified as ADR Class 9 (Environmentally Hazardous Substances). UN number is 3082. Classified as a marine pollutant. Precautions against leakage must be taken during transport.

7. Oxidation Sensitivity: Due to its double bond-containing structure, DOM is sensitive to oxidation during long-term storage. Storage under inert gas (nitrogen) or addition of suitable antioxidants is recommended to prevent oxidation.

8. Hydrolysis Sensitivity: DOM can hydrolyze in the presence of moisture, forming maleic acid and 2-ethylhexanol. Therefore, the product must be protected from moisture and stored in dry conditions.

IMPORTANT DISCLAIMER: This Technical Data Sheet (TDS) is for informational purposes only and is prepared based on available technical data. The information provided is believed to be accurate. However, the user is solely responsible for determining the product's suitability for their specific applications and for complying with all applicable local, national and international regulations and safety requirements. For complete safety, storage, handling, transport, waste and regulatory compliance information, please refer to the official Safety Data Sheet (SDS/MSDS) provided by the manufacturer/supplier. Users are obligated to test the product in their own processes and applications. All occupational health and safety rules must be observed when working with Dioctyl Maleate.