Phthalic Anhydride (PA) CAS 85-44-9
As a reliable Phthalic Anhydride supplier, we deliver premium industrial-grade flake and molten PA tailored for the global plasticizer, polyester resin, and alkyd resin industries. Our strict quality control protocols secure consistent purity to optimize your large-scale manufacturing chemical reactions.
Phthalic Anhydride (PA) is a vital cyclic anhydride obtained from the catalytic oxidation of ortho-xylene or naphthalene. Appearing as white crystalline flakes, it is one of the most important organic chemical raw materials utilized globally for synthesizing downstream polymers and chemical intermediates.
- High Chemical Purity: Minimum 99.5% assay ensures high reaction yields and minimal byproduct formation in resin synthesis.
- Excellent Thermal Stability: Maintains structural integrity under melting processing, ideal for high-temperature esterification.
- Strict Moisture Control: Carefully packaged and sealed to prevent hydration into phthalic acid during long-distance maritime transit.
Phthalic Anhydride Description
Name: Phthalic anhydride (PA)
Synonyms: 2-Benzofuran-1,3-dione / Phthalandione /Isobenzofuran-1,3-dione
Molecular Formula: C8H4O3
Molecular Weight: 148.12
CAS NO.: 85-44-9
Density: 1.4±0.1 g/cm3
Boiling point: 295 °C
Melting point: 131.6 °C
Flashing point: 152 ºC
Appearance: White crystalline flakes or needles
Solubility: Sparingly soluble in cold water (reacts slowly to form phthalic acid). Soluble in hot water, alcohol, ether, and benzene.
Properties: Phthalic Anhydride is a volatile crystalline solid that sublimes easily at temperatures below its boiling point. It undergoes rapid esterification when reacted with alcohols, making it a powerful monomer for polymer networks. It is hygroscopic and must be protected from ambient humidity.
Package: Standard packaging is 25 kg net per woven polypropylene bag with an inner polyethylene moisture barrier, or 500kg/1000kg bulk jumbo bags. Customized container-load configurations are available upon request.
Storage: Store in a cool, dry, and exceptionally well-ventilated chemical warehouse. Keep containers tightly sealed and isolated from moisture, strong oxidizing agents, strong acids, and strong bases.
Safety Protection: It is locally irritating to the skin and mucous membranes, sometimes causing severe inflammation and blisters, and many of them form ulcers that are difficult to heal. Its toxicity is slightly lower than that of benzoic acid. In production, water spray capture method can be used to reduce the concentration of phthalic anhydride in the workshop air. Operators should wear labor protection equipment.
Phthalic Anhydride Technical
| Item | Index |
| Appearance | White crystalline flakes |
| Molten Chroma(Chroma No. )≤ | 20 |
| Thermostable Chroma(Chroma No. )≤ | 50 |
| Chroma Of Vitriol(Chroma No. )≤ | 60 |
| Crystallization Point°c≥ | 130.5 |
| Purity(Mass Fraction)%≥ | 99.80 |
| Free Acid(Mass Fraction)≤ % | 0.20 |
As a certified Phthalic Anhydride factory, we monitor critical molten color indexes and crystallizing temperatures to guarantee excellent performance in optical-grade resins and premium coatings.
Phthalic Anhydride Applications
- Plasticizers Production: The primary application of PA is manufacturing phthalate esters such as DOP (Dioctyl Phthalate), DINP(Diisononyl Phthalate), and DBP. These serve as essential plasticizers to impart flexibility and durability to PVC resins.
- Unsaturated Polyester Resins (UPR): Functions as a core building block in synthesizing unsaturated polyester resins, which are widely reinforced with fiberglass to produce composites for automotive, marine, and construction industries.
- Alkyd Resins & Surface Coatings: Extensively utilized in reacting with polyols to formulate high-performance alkyd resins, which form the base matrix for decorative paints, industrial enamels, and marine coatings.
- Dyes and Pigments: Acts as an intermediate in producing quinoline yellow, phthalein dyes, and anthraquinone derivatives for the textile and plastics coloration sectors.
- Saccharin & Pharmaceuticals: Serves as a chemical stepping stone for synthesizing saccharin, crop-protection agrochemicals, and specific pharmaceutical intermediates.
FAQs about Phthalic Anhydride (PA)
Q1: What happens if Phthalic Anhydride flakes are exposed to ambient moisture?
Phthalic Anhydride is hygroscopic and reacts slowly with water or moisture in the air to undergo a hydrolysis reaction. This converts the anhydride into Phthalic Acid (C8H6O4). The presence of excessive phthalic acid as an impurity raises the total free acid content, which can disrupt the stoichiometry and slow down esterification rates in downstream resin production.
Q2: Why is the “Molten Color” index so critical for PA buyers?
The molten color index (measured in Hazen/APHA units) indicates the level of trace organic impurities or oxidation byproducts present in the material. For manufacturers of premium clear plasticizers or light-colored alkyd coatings, a low molten color (typically ≤20) is essential to prevent yellowing and ensure optical clarity in the finished product.
Q3: What are the standard packaging and logistics configurations for exporting PA?
Our standard export configuration uses 25kg moisture-proof woven bags. For a standard 20GP container, we can load 20 Metric Tons (MT) with pallets, or up to 22 MT without pallets. For high-volume industrial facilities, we also provide 1,000kg jumbo bags equipped with anti-static liners to minimize dust hazards during unloading.
Q4: Does Phthalic Anhydride require dangerous goods (DG) classification for sea freight?
Yes, solid Phthalic Anhydride is classified under UN 2214, Class 8 (Corrosive Substances) due to its potential to cause skin burns and respiratory irritation upon dust inhalation. Our logistics team handles all mandatory GHS labeling and IMDG documentation to guarantee seamless custom clearance at global ports.
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