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Phthalic Anhydride

Phthalic Anhydride

ELRASA™TM – PTAn

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Phthalic anhydride (PA; also called phthalic acid anhydride; C₈H₄O₃, CAS 85-44-9) is a versatile chemical intermediate supplied as white crystalline flakes or molten bulk. It is the primary dibasic…

CAS Number

85-44-9

HS Code

29.17.35.00

INCI Name

Phthalic Anhydride

Molecular Formula

C8H4O3

Home/Products/Phthalic Anhydride

Phthalic Anhydride

ELRASA™TM – PTAn

Phthalic anhydride (PA; also called phthalic acid anhydride; C₈H₄O₃, CAS 85-44-9) is a versatile chemical intermediate supplied as white crystalline flakes or molten bulk. It is the primary dibasic building block for phthalate plasticizers, unsaturated polyester resins (UPR) and…

CAS Number

85-44-9

INCI Name

Phthalic Anhydride

HS Code

29.17.35.00

Molecular Formula

C8H4O3

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Speed Up Your Sample Testing Process

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Phthalic Anhydride

Product Specification

AppearanceWhite, lustrous needles or flakes.
OdorMild, characteristic, acrid, choking odor.
Molecular Weight148.11 g/mol
Density1.53 g/cm³
Specific Gravity1.53
Viscosity (Molten)1.19 mPa·s at 132 °C
Refractive Index1.646
Ph (Aqueous Solution)Forms a corrosive solution; hydrolyzes to Phthalic acid.
Assay / Purity≥99%

Physical Properties

PropertySpecification
AppearanceWhite, lustrous needles or flakes.
OdorMild, characteristic, acrid, choking odor.
Molecular Weight148.11 g/mol
Density1.53 g/cm³
Specific Gravity1.53
Viscosity (Molten)1.19 mPa·s at 132 °C
Refractive Index1.646
Ph (Aqueous Solution)Forms a corrosive solution; hydrolyzes to Phthalic acid.
Assay / Purity≥99%

Chemical Properties

PropertySpecification
PkaNo reliable source found.
Ionic NatureNon-ionic; behaves as a Lewis acid.
IncompatibilitiesStrong oxidizers, strong acids, strong bases, alcohols, amines, water, copper oxide, and sodium nitrite.
Hazardous Reactions / Decomposition ProductsReacts exothermically with water to form Phthalic Acid. Reaction can be violent when heated with copper oxide or sodium nitrite. When heated to decomposition, may emit toxic fumes including carbon monoxide and carbon dioxide.

Thermal Properties

PropertySpecification
Melting Point131 °C
Boiling Point284 °C (sublimes)
Flash Point152 °C (closed cup)
Autoignition Temperature570 °C
Decomposition TemperatureNo decomposition reported below boiling point.
Thermal StabilityStable under normal conditions of storage and handling. Heat contributes to instability.

Dosing Guidelines

A. Dosing by Application

ApplicationRecommended / Max Dosage
Alkyd ResinsTypically used as a primary dibasic acid component, with the amount determined by the desired oil length and performance characteristics of the resin.
Unsaturated Polyester ResinsA key component reacted with glycols and unsaturated dibasic acids/anhydrides. The ratio determines the resin's properties, such as rigidity and chemical resistance.
Phthalate PlasticizersUsed as the primary reactant with various alcohols (e.g., 2-ethylhexanol, butanol) to produce esters like DEHP and DBP. The dosage is based on a 1:2 molar ratio of anhydride to alcohol.

About Phthalic Anhydride

Phthalic anhydride (PA; also called phthalic acid anhydride; C₈H₄O₃, CAS 85-44-9) is a versatile chemical intermediate supplied as white crystalline flakes or molten bulk. It is the primary dibasic building block for phthalate plasticizers, unsaturated polyester resins (UPR) and alkyd resins and coatings (CASE), as well as dyes and pigments. Elchemy supplies high-quality, technical-grade (≥99%) phthalic anhydride in bulk with full documentation; download the technical data sheet (TDS) for specifications.


Phthalic Anhydride Grades & Forms: Flakes & Molten

Phthalic anhydride is supplied as flakes (white crystalline, easy to weigh and handle for batch use) and as molten bulk (delivered hot in insulated tankers for large continuous plants). Standard material is high-quality technical grade at ≥99% purity, suitable for plasticizers, UPR and alkyd production. Tell us your process and volume and we will recommend flakes or molten supply and the right specification.


Phthalic Anhydride Supplier, Manufacturer & Distributor

Elchemy is a phthalic anhydride supplier, distributor and sourcing company serving plasticizer, resin, coatings and dye manufacturers across the US and worldwide. Working directly with producers, we provide consistent, high-quality technical-grade PA with full documentation (CoA, TDS, SDS) and dependable lead times. Whether you need flakes for batch use or a qualified phthalic anhydride manufacturer partner for molten bulk supply, our team handles specification, sampling and supply continuity so procurement stays predictable.


Buy Phthalic Anhydride in Bulk - Price Trend & Quotes

Looking to buy phthalic anhydride in bulk? Elchemy offers competitive pricing on flakes and molten PA, from bag and drum quantities to full loads. Because the phthalic anhydride price follows a market trend driven by o-xylene feedstock and order volume, we quote per requirement rather than list a fixed rate, and can advise on current price direction. Request a bulk quote for prices within 48 hours, or request a sample for evaluation. For buyers comparing phthalic anhydride suppliers with reliable delivery and documentation, start with a quote and we'll confirm grade, form, availability and shipping.

  • Versatile Chemical Intermediate: Essential for producing plasticizers, resins, and coatings.
  • Function: Chemical intermediate, monomer, plasticizer precursor, resin former.
  • High Purity Standards: Ensures performance in critical applications like automotive and construction.
  • Features: High reactivity, bifunctional nature, enhances flexibility and durability in polymers.
  • Eco-Friendly Production: Focus on minimizing environmental impact through sustainable practices.
  • Benefits: Improves adhesion, weather resistance, and toughness in coatings; provides flexibility to PVC products; enables the creation of strong, durable fiberglass-reinforced plastics.
  • Enhances Material Performance: Improves flexibility, durability, and resistance in end products.
  • Wide Industrial Use: Key component in dyes, pigments, and pharmaceuticals.

About Phthalic Anhydride

Phthalic anhydride (PA; also called phthalic acid anhydride; C₈H₄O₃, CAS 85-44-9) is a versatile chemical intermediate supplied as white crystalline flakes or molten bulk. It is the primary dibasic building block for phthalate plasticizers, unsaturated polyester resins (UPR) and alkyd resins and coatings (CASE), as well as dyes and pigments. Elchemy supplies high-quality, technical-grade (≥99%) phthalic anhydride in bulk with full documentation; download the technical data sheet (TDS) for specifications.


Phthalic Anhydride Grades & Forms: Flakes & Molten

Phthalic anhydride is supplied as flakes (white crystalline, easy to weigh and handle for batch use) and as molten bulk (delivered hot in insulated tankers for large continuous plants). Standard material is high-quality technical grade at ≥99% purity, suitable for plasticizers, UPR and alkyd production. Tell us your process and volume and we will recommend flakes or molten supply and the right specification.


Phthalic Anhydride Supplier, Manufacturer & Distributor

Elchemy is a phthalic anhydride supplier, distributor and sourcing company serving plasticizer, resin, coatings and dye manufacturers across the US and worldwide. Working directly with producers, we provide consistent, high-quality technical-grade PA with full documentation (CoA, TDS, SDS) and dependable lead times. Whether you need flakes for batch use or a qualified phthalic anhydride manufacturer partner for molten bulk supply, our team handles specification, sampling and supply continuity so procurement stays predictable.


Buy Phthalic Anhydride in Bulk - Price Trend & Quotes

Looking to buy phthalic anhydride in bulk? Elchemy offers competitive pricing on flakes and molten PA, from bag and drum quantities to full loads. Because the phthalic anhydride price follows a market trend driven by o-xylene feedstock and order volume, we quote per requirement rather than list a fixed rate, and can advise on current price direction. Request a bulk quote for prices within 48 hours, or request a sample for evaluation. For buyers comparing phthalic anhydride suppliers with reliable delivery and documentation, start with a quote and we'll confirm grade, form, availability and shipping.

  • Versatile Chemical Intermediate: Essential for producing plasticizers, resins, and coatings.
  • Function: Chemical intermediate, monomer, plasticizer precursor, resin former.
  • High Purity Standards: Ensures performance in critical applications like automotive and construction.
  • Features: High reactivity, bifunctional nature, enhances flexibility and durability in polymers.
  • Eco-Friendly Production: Focus on minimizing environmental impact through sustainable practices.
  • Benefits: Improves adhesion, weather resistance, and toughness in coatings; provides flexibility to PVC products; enables the creation of strong, durable fiberglass-reinforced plastics.
  • Enhances Material Performance: Improves flexibility, durability, and resistance in end products.
  • Wide Industrial Use: Key component in dyes, pigments, and pharmaceuticals.

Regulatory Compliance

RegionMax Allowed LevelNotesCertification Body
Republic of Korea-Subject to registration under K-REACH.-
ASEAN-Not specifically restricted in the ASEAN Cosmetic Directive, as its primary uses are industrial, not cosmetic.-
China-Listed on the Inventory of Existing Chemical Substances in China (IECSC).-
United States-Regulated by the EPA under the Toxic Substances Control Act (TSCA) and by OSHA for workplace safety. EPA is conducting a risk evaluation, which preliminarily found unreasonable risks to workers and consumers for certain uses. It is listed on the TSCA Inventory.TSCA compliance.
European Union-Registered under REACH. Harmonised classification and labelling (CLP) apply: Acute Tox. 4, Skin Irrit. 2, Eye Dam. 1, Resp. Sens. 1, Skin Sens. 1, STOT SE 3.REACH Registration.
Canada-Not specifically restricted. Listed on the Domestic Substances List (DSL).-
India-The Phthalic Anhydride (Quality Control) Order, 2020 mandates that the product must conform to Indian Standard IS 5158:1987 and bear the BIS Standard Mark (ISI Mark) for manufacturing, sale, or import. This does not apply to products intended for export.BIS (ISI Mark) Certification per IS 5158:1987.
Japan-Listed on the Chemical Substance Control Law (CSCL) inventory.-
Australia-Listed on the Australian Inventory of Industrial Chemicals (AIIC).-

FAQs - Phthalic Anhydride

What is Phthalic Anhydride used for?
Phthalic Anhydride is primarily used in the production of plasticizers, unsaturated polyester resins, and alkyd resins.
Is Phthalic Anhydride hazardous?
Yes, it can be hazardous if inhaled or if it comes into contact with skin. Proper safety measures should be taken when handling.
How should Phthalic Anhydride be stored?
It should be stored in a cool, dry place away from incompatible materials such as strong oxidizing agents.
What is phthalic anhydride?
Phthalic anhydride (PA, C₈H₄O₃, CAS 85-44-9), also called phthalic acid anhydride, is a white crystalline chemical intermediate supplied as flakes or molten bulk. It is a key dibasic building block for plasticizers, unsaturated polyester resins and alkyd resins.
Is phthalic acid anhydride the same as phthalic anhydride?
Yes. "Phthalic acid anhydride" is another name for phthalic anhydride - the anhydride of phthalic acid. It reacts with water to form phthalic acid, and with alcohols to form phthalate esters.
What forms and grades of phthalic anhydride are available?
Phthalic anhydride is supplied as flakes (convenient for batch weighing and handling) and as molten bulk (delivered hot in insulated tankers for large continuous plants). Standard material is high-quality technical grade at ≥99% purity.
How is phthalic anhydride manufactured?
Industrially, phthalic anhydride is made by the catalytic vapour-phase oxidation of o-xylene (or naphthalene) over a vanadium-pentoxide catalyst, followed by condensation and purification into flakes or molten product.
Is phthalic anhydride dangerous, and how should it be handled?
Phthalic anhydride is an irritant to eyes, skin and the respiratory tract and can cause sensitisation; it is combustible and reacts exothermically with water. Handle with PPE and good ventilation, keep away from water, bases, alcohols and oxidisers, and store cool and dry. Follow the SDS for full guidance.
What is the reaction of phthalic anhydride with water?
Phthalic anhydride reacts exothermically with water to form phthalic acid. This is why it must be kept dry during storage and handling to preserve assay and avoid caking.
How much phthalic anhydride is used to make plasticizers?
In phthalate plasticizer production, phthalic anhydride is reacted with an alcohol at roughly a 1:2 molar ratio (anhydride to alcohol) to form the diester plasticizer.
What is the phthalic anhydride price trend?
Phthalic anhydride price tracks its o-xylene feedstock and supply/demand balance, so it moves with the market. Because of this we quote per requirement rather than a fixed rate and can advise on current price direction - request a quote for prices within 48 hours.
Where can I buy phthalic anhydride in bulk?
Elchemy supplies phthalic anhydride in bulk across the US and internationally, as flakes or molten, from bags and drums to full loads. Request a quote and our team confirms grade, form, availability and delivery.
Does Elchemy provide documentation for phthalic anhydride?
Yes. Elchemy provides the certificate of analysis (CoA), technical data sheet (TDS) and SDS so you have full specification, quality and compliance documentation (TSCA, REACH, BIS as applicable) before purchase.

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