Technical Specifications of Phthalic Anhydride (PA)

1. General Information

Chemical Name:Phthalic Anhydride

CAS Number:85-44-9

Molecular Formula:C8H4O3

Molecular Weight:148.11 g/mol

Physical State:White crystalline solid

Odor:Pungent, irritating

2. Physical and Chemical Properties

3. Purity and Composition

3.1 Main Content

• Phthalic Anhydride (PA): ≥ 99.5% (by weight)
• Phthalic Acid: ≤ 0.5% (by weight)
• o-Xylene: ≤ 0.05% (by weight)
• Other Impurities: ≤ 0.1% (by weight)

3.2 Key Impurities

Phthalic Acid:Formed by the hydrolysis of PA, affects product quality and storage stability.

o-Xylene:Unreacted raw material, may cause odor issues in downstream applications.

Other Impurities:Including maleic anhydride, benzoic acid, etc., which can impact the performance of PA in polymer production.

4. Quality Control Parameters

5. Application-Specific Requirements

5.1 For Plasticizers Production

• Low phthalic acid content (≤ 0.3%) to ensure the efficiency of esterification reactions.
• Low color (APHA ≤ 10) to produce clear plasticizers.
• Low moisture content (≤ 0.05%) to prevent side reactions during processing.

5.2 For Unsaturated Polyester Resins

• High purity (≥ 99.8%) to ensure resin quality and curing properties.
• Low ash content (≤ 0.01%) to avoid defects in composite materials.
• Consistent acid value to maintain resin formulation stability.

5.3 For Alkyd Resins

• Controlled phthalic acid content (≤ 0.4%) to balance resin viscosity and drying time.
• Low sulfur content (≤ 10 ppm) to prevent discoloration in coatings.

6. Safety and Handling

• Flash Point:151°C (closed cup)
• Autoignition Temperature:570°C
• Explosive Limits:1.7-10.5% (v/v in air)
• Handling:Avoid contact with skin and eyes; use in well-ventilated areas; store in cool, dry place away from incompatible materials (e.g., strong oxidizers, strong bases).

7. Packaging and Storage

• Packaging:25 kg bags (polyethylene-lined paper bags) or 500 kg bulk bags.
• Storage:Shelf life of 12 months when stored in original, unopened packaging at room temperature and relative humidity ≤ 75%.

8. Environmental Considerations

• Biodegradability:Not readily biodegradable; may persist in the environment.
• Water Hazard Class:Class 1 (slightly hazardous)
• Regulatory Compliance:Complies with REACH, OSHA, and other relevant international standards.