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Phthalic anhydride

CAS Number
85-44-9
EC Number
201-607-5
Chemical Formula
C8H4O3
Molecular Weight
148.11 g/mol

Description

Phthalic anhydride (CAS 85-44-9 ), commonly abbreviated as PA, is a white crystalline solid produced by the catalytic oxidation of naphthalene or o-xylene. It functions as a foundational chemical intermediate. This material supplies reactive anhydride groups for the synthesis of resins, plasticizers, dyes, and specialty esters across multiple industrial sectors. PA is the primary building block for alkyd resins. These resins are used in architectural and industrial coatings, where it controls resin hardness, drying behavior, and film durability. In plastics processing, it reacts with alcohols to produce phthalate plasticizers. These plasticizers modify flexibility in PVC compounds for cables, flooring, and packaging films. Unsaturated polyester resins for composites and laminates rely on PA as a key monomer for production. It determines the crosslink density and mechanical performance of the cured material. It also serves as a precursor to phthalocyanine pigments and to synthetic musks and fragrance intermediates. These intermediates are used in personal care formulations. Phthalic anhydride is supplied as white flakes or molten liquid, with flake form being the standard for bulk and bagged shipments. Technical grade is the predominant commercial specification, with purity typically at 99.5% or higher. It is available in bulk tankers, bulk bags, and 25 kg bags depending on application requirements. Contact us for supply of Phthalic anhydride Request Quote

Other Names (Synonyms)

phthalic acid anhydride | ortho-phthalic acid anhydride | o-phthalic acid anhydride | isobenzofuran-1,3-dione | 2-benzofuran-1,3-dione | 1,3-phthalandione | 1,3-isobenzofurandione | 1,3-dioxophthalan | PA

Key Technical Features

  • High Purity Grade standard
  • Consistent Batch Quality
  • Full Regulatory & REACH Support
  • Global Logistics Network enabled

Physical Properties

Melting Point130.8 °C
Boiling Point295 °C
Density1.53 g/cm³
Flash Point152 °C
AppearancePhthalic Anhydride is moderately flammable, white solid (flake) or a clear, colorless, mobile liquid (molten) Characteristic, acrid, choking odor
ColorWhite
OdorCharacteristic choking odor
FormFlaky Crystals
Water Solubility6 g/L (20 ºC)
Vapor Pressure<0.01 mm Hg ( 20 °C)
Refractive Index1.4500 (estimate)
pH2 (6g/l, H2O, 20℃)
Log P2.07 at 20℃

Safety & Handling

Danger
GHS05· CorrosiveGHS07· IrritantGHS08· Health Hazard

Hazard Statements

H302Harmful if swallowed
H315Causes skin irritation
H317May cause an allergic skin reaction
H318Causes serious eye damage
H319Causes serious eye irritation
H334May cause allergy or asthma symptoms or breathing difficulties if inhaled
H335May cause respiratory irritation
H336May cause drowsiness or dizziness
H361Suspected of damaging fertility or the unborn child
H371May cause damage to organs
H372Causes damage to organs through prolonged or repeated exposure
H402Harmful to aquatic life

Precautionary Statements

P203Obtain, consult and follow expert instructions for use.
P233Keep container tightly closed.
P260Do not breathe dust/fume/gas/mist/vapours/spray.
P261Avoid breathing dust/fume/gas/mist/vapours/spray.
P264Wash … thoroughly after handling.
P270Do not eat, drink or smoke when using this product.
P271Use only outdoors or in a well-ventilated area.
P272Contaminated work clothing should not be allowed out of the workplace.
P273Avoid release to the environment.
P280Wear protective gloves/protective clothing/eye protection/face protection.
P284In case of inadequate ventilation wear respiratory protection.
P317Get emergency medical help.
P318IF exposed or concerned, get medical advice.
P319Get medical advice/attention if you feel unwell.
P321Specific treatment (see … on this label).
P330Rinse mouth.
P403Store in a well-ventilated place.
P405Store locked up.
P501Dispose of contents/container in accordance with local regulations.
P265Wash … thoroughly after handling.
P317Get emergency medical help.
P352IF ON SKIN: Wash with plenty of water.
P340IF INHALED: Remove person to fresh air and keep comfortable for breathing.
P316Get emergency medical help immediately.
P317Get emergency medical help.
P317Get emergency medical help.
P317If eye irritation persists: Get medical advice/attention. Get emergency medical help.
P316Get emergency medical help immediately.
P364Take off contaminated clothing and wash it before reuse.
P233Store in a well-ventilated place. Keep container tightly closed.
P338IF IN EYES: Rinse cautiously with water for several minutes. Remove contact lenses, if present and easy to do. Continue rinsing.
P338IF IN EYES: Rinse cautiously with water for several minutes. Remove contact lenses, if present and easy to do. Continue rinsing.

Trade & Regulatory

HS Code29173500
Storage Class11 - Combustible Solids
WGK (Germany)1