Phthalic Anhydride — Technical Product Overview
Phthalic Anhydride is an aromatic organic compound and one of the most important industrial intermediates in the chemical and polymer industries. It is primarily used as a key building block for plasticizers, alkyd resins, unsaturated polyester resins, and various dye intermediates.
It is the cyclic anhydride of phthalic acid and is widely produced on an industrial scale due to its high reactivity and extensive downstream applications.
Chemical Identity
- Chemical Name: Phthalic Anhydride
• Molecular Formula: C₈H₄O₃
• Molecular Weight: 148.11 g/mol
• CAS Number: 85-44-9
• Appearance: White crystalline flakes or needles
• Odor: Pungent, slightly acrid odor
• Physical State: Solid at ambient conditions
• Melting Point: Approximately 131–134°C
• Boiling Point: Approximately 284–295°C (sublimes)
• Solubility: Reacts with water to form phthalic acid; soluble in organic solvents
Production Process
Phthalic Anhydride is produced through the catalytic oxidation of aromatic hydrocarbons, primarily:
• Ortho Xylene (preferred modern feedstock)
• Naphthalene (older production route)
The process is carried out in fixed-bed catalytic reactors under controlled temperature conditions, followed by condensation and purification stages to obtain high-purity product suitable for industrial applications.
Storage & Handling
- Store in tightly sealed containers in dry conditions
• Protect from moisture due to hydrolysis sensitivity
• Avoid exposure to humidity and water
• Use proper industrial PPE during handling
• Follow chemical safety regulations for solid organic acids
Industrial Applications
- Plasticizer Production
Phthalic Anhydride is a core raw material for the production of phthalate esters, which are widely used as plasticizers in:
• PVC products
• flexible plastics
• cables and wiring insulation
• synthetic leather
- Unsaturated Polyester Resins (UPR)
It is a key ingredient in UPR manufacturing, used in:
• fiberglass reinforced plastics (FRP)
• construction materials
• marine and automotive composites
• coatings and laminates
- Alkyd Resins
Phthalic Anhydride is extensively used in alkyd resin production for:
• industrial paints
• protective coatings
• varnishes and enamels
• architectural coatings
- Dyes and Pigments
It serves as an intermediate in the synthesis of:
• phthalein dyes
• synthetic colorants
• indigo derivatives
• specialty pigments
- Other Chemical Derivatives
It is also used in the production of:
• benzoic acid derivatives
• agrochemicals
• pharmaceuticals intermediates
• specialty fine chemicals
Key Industrial Advantages
- High chemical reactivity with alcohols and glycols
• Essential intermediate for polymer and resin industries
• Enables production of durable and flexible polymer systems
• Compatible with large-scale continuous industrial processes
• Stable global demand across coatings, plastics, and composites industries
• Highly versatile aromatic intermediate
Maleic Anhydride — Technical Product Overview
Maleic Anhydride is an important industrial chemical intermediate widely used in the production of resins, coatings, additives, agricultural chemicals, and specialty chemical formulations. It is a highly reactive organic compound derived mainly from the catalytic oxidation of hydrocarbons such as benzene or n-butane and serves as a key raw material in several downstream industries.
Due to its strong reactivity and versatility in chemical synthesis, Maleic Anhydride plays a critical role in the manufacture of unsaturated polyester resins, lubricating oil additives, copolymers, plasticizers, and agricultural intermediates. Its broad industrial relevance makes it one of the essential building blocks in the chemical and petrochemical sectors.
Chemical Identity
- Chemical Name: Maleic Anhydride
- Synonyms: 2,5-Furandione, Cis-Butenedioic Anhydride
- Molecular Formula: C₄H₂O₃
- Molecular Weight: 98.06 g/mol
- CAS Number: 108-31-6
- Appearance: White briquettes, flakes, or molten liquid depending on form and packaging
- Odor: Pungent, irritating odor
- Physical State: Solid at ambient conditions / molten liquid when heated
- Melting Point: Approximately 52.8°C
- Boiling Point: Approximately 202°C
- Density: Approximately 1.48 g/cm³
- Solubility in Water: Reacts with water to form maleic acid
- Solubility in Organic Solvents: Soluble in many polar organic solvents
Production Process
Maleic Anhydride is primarily produced through catalytic vapor-phase oxidation of hydrocarbons, mainly:
- n-Butane Oxidation
- Benzene Oxidation (older process in some facilities)
The process involves oxidation in the presence of a catalyst, followed by recovery, condensation, purification, and solidification or molten handling systems to obtain industrial-grade Maleic Anhydride for downstream chemical applications.
Key Industrial Advantages
- Important raw material for unsaturated polyester resin production
- Highly reactive intermediate for a broad range of chemical syntheses
- Valuable component in lubricant additive manufacturing
- Supports performance enhancement in resins, polymers, and coatings
- Widely used across construction, automotive, chemical, and agricultural sectors
- Available in solid and molten forms for industrial processing needs
- Strong demand in downstream petrochemical and specialty chemical industries
Storage & Handling
- Store in dry, tightly closed containers or dedicated molten storage systems
- Protect from moisture and water contact
- Keep in cool, dry, and well-ventilated areas
- Avoid direct contact with skin, eyes, and respiratory exposure
- Use appropriate industrial PPE during handling
- Handle molten Maleic Anhydride with suitable temperature control systems
- Follow applicable regulations for storage, transport, and industrial chemical handling
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Industrial Applications
- Unsaturated Polyester Resin (UPR) Production
Maleic Anhydride is extensively used in the manufacture of:
- unsaturated polyester resins
- fiberglass reinforced plastics
- construction panels
- sanitary ware
- marine composites
- automotive composite parts
It is one of the key raw materials in resin systems used for durable, lightweight, and corrosion-resistant composite products.
- Chemical Intermediate
Maleic Anhydride is a key feedstock for producing:
- fumaric acid
- malic acid
- succinic acid derivatives
- tetrahydrophthalic anhydride
- 1,4-butanediol intermediates
- specialty esters and chemical derivatives
Its reactivity makes it highly valuable in a wide range of organic synthesis routes.
- Lubricant Additives
Maleic Anhydride is widely used in the production of:
- lubricating oil additives
- dispersants
- detergent additives
- fuel additives
- viscosity modifier intermediates
These additives help improve engine cleanliness, oxidation stability, and lubricant performance.
- Coatings, Paints & Resin Systems
Maleic Anhydride is utilized in:
- alkyd resin modification
- coating resins
- surface treatment formulations
- protective coatings
- industrial paint systems
- polymeric binders
It contributes to resin performance, chemical functionality, and formulation flexibility.
- Agricultural & Specialty Chemicals
Maleic Anhydride is used in the production of:
- agrochemical intermediates
- pesticide formulations
- plant protection chemicals
- specialty chemical products
- water treatment and functional chemical formulations
- Polymer & Copolymer Production
Maleic Anhydride is used in the manufacture of:
- copolymers and grafted polymers
- paper treatment chemicals
- textile auxiliaries
- adhesives and sealants
- performance polymers
It is often incorporated to introduce functional groups and improve polymer compatibility and reactivity.