4,4'-(4,4'-Isopropylidenediphenoxy)bis(phthalic anhydride)
[CAS 38103-06-9]

Identification

• Classification: Chemical reagent >> Organic reagent >> Ether
• Name: 4,4'-(4,4'-Isopropylidenediphenoxy)bis(phthalic anhydride)
• Synonyms: 5,5'-[2,2-Propanediylbis(4,1-phenyleneoxy)]bis(2-benzofuran-1,3-dione); BPADA
• Molecular Formula: C₃₁H₂₀O₈
• Molecular Weight: 520.49
• CAS Registry Number: 38103-06-9
• EC Number: 253-781-7
• SMILES: CC(C)(C1=CC=C(C=C1)OC2=CC3=C(C=C2)C(=O)OC3=O)C4=CC=C(C=C4)OC5=CC6=C(C=C5)C(=O)OC6=O

Properties

• Density: 1.4±0.1 g/cm³ Calc.^*
• Melting point: 184 - 187 °C (Expl.)
• Boiling point: 712.3±60.0 °C 760 mmHg (Calc.)^*
• Flash point: 302.2±32.9 °C (Calc.)^*
• Index of refraction: 1.657 (Calc.)^*

^* Calculated using Advanced Chemistry Development (ACD/Labs) Software.

Safety Data

• Hazard Symbols: GHS07 Warning
• Risk Statements: H302-H315-H319-H332-H335
• Safety Statements: P261-P280-P305+P351+P338

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Eye irritation	Eye Irrit.	2	H319
Skin irritation	Skin Irrit.	2	H315

chemBlink Chemical Story

4,4'-(4,4'-Isopropylidenediphenoxy)bis(phthalic anhydride), CAS 38103-06-9, is usually abbreviated BPADA and is also called bisphenol A dianhydride. It is a difunctional aromatic dianhydride used as a monomer for high-performance polyimides. TCI and Sigma-Aldrich identify the compound under these names and document its role in polyimide research.

Polyimides are commonly formed by reacting a dianhydride with a diamine. Each anhydride group reacts with amine functionality to form a poly(amic acid) precursor, which is subsequently cyclized, or imidized, to generate the heat-resistant polyimide backbone. Because BPADA carries two phthalic anhydride groups, it can connect repeatedly with difunctional diamines and build high-molecular-weight chains.

What distinguishes BPADA from very rigid dianhydrides is its central bisphenol-A-derived ether structure. Aromatic rings provide thermal robustness, while ether linkages and the isopropylidene center introduce rotational freedom and disrupt extremely tight chain packing. This structural balance can improve solubility and processability relative to more rigid polyimides while retaining useful thermal and mechanical properties.

That tradeoff is important in advanced polymers. A polymer can have excellent heat resistance yet be difficult to dissolve, coat or fabricate. Flexible ether linkages and non-linear geometry are therefore deliberately incorporated into some polyimide monomers to make precursor solutions and final materials easier to process. Published work cited by suppliers discusses BPADA-containing polyimides and copolyimides designed for improved solubility while maintaining high-performance properties relevant to electronics and aerospace materials.

BPADA is consequently a monomer whose large, complicated structure has a clear purpose. The two anhydrides are polymer-forming endpoints; the aromatic core provides stability; ether and isopropylidene linkages tune chain mobility and packing. Its molecular architecture anticipates the compromises required of a real engineering polymer before polymerization even begins.

References:
1. TCI America, BPADA, CAS 38103-06-9.
2. Sigma-Aldrich, 4,4'-(4,4'-Isopropylidenediphenoxy)bis(phthalic anhydride), product 478032.
3. Sroog CE. Polyimides. Prog Polym Sci. 1991;16:561-694.

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