4,4'-(Hexafluoroisopropylidene)diphthalic anhydride

4,4'-(Hexafluoroisopropylidene)diphthalic anhydride (6FDA) is an aromatic organofluorine compound that is utilized as a dianhydride monomer. It is among the most frequently used dianhydride monomers due to its exceptional balance of mechanical and electrical properties. It is particularly prominent in the construction of colorless and transparent polyimides.

Beige crystal

4,4'-(Hexafluoroisopropylidene) diphthalic anhydride is involved in the synthesis of polyamides derived from terphenylenes, which is used for gas separation.

4,4'-(Hexafluoroisopropylidene)diphthalic anhydride (6FDA) can be used:
(1) With APAF as dianhydride monomer, it can be used to prepare thermally rearranged polybenzoxazole (TR-PBO) gas separation membranes by thermal rearrangement reaction at 450°C. The product TR-PBO membrane has excellent gas permeation selectivity and high permeability. the H2/CH4 separation performance of APAF-6FDA membrane is close to the Robertson upper limit of 2008 ^[5].
(2) Used as a raw material for the preparation of thermoplastic fluorinated polyimide resin.^[6].
(3) Polymers for electronic materials;
(4) Polyimide materials. These materials can be used as substrates for wearable devices and as multilayer insulation materials in order to protect against space dust, cosmic rays and satellite debris^[7].

4,4'-(Hexafluoroisopropylidene)diphthalic anhydride (6FDA) consists of two phthalic anhydrides bridged with a perfluoroisopropyl group and is mainly used in the synthesis of polyimides. Polyimides from 6FDA are commonly used in hybrid matrix membranes. The polyimide matrix provides good dispersion of the filler and can be loaded with up to 50 wt% filler. These membranes have been used for highly selective gas separation (CO2/CH4) and solar cell encapsulation (power conversion efficiency of silicon-based solar cells increased from 14.67% to 15.64%).

The 4,4'-(hexafluoroisopropylidene) diphthalic anhydride (6FDA) monomer contains rigid benzene ring groups, and so, the resulting polymer has excellent mechanical properties. 6FDA contained a stable benzene ring and fluorine atoms. Due to the strong electronegativity of the fluorine atoms and the stability of the benzene ring, the produced polycarbonate had better thermal stability[1-2].

The storage precautions for 6FDA are as follows: The chemical must be stored in a cool and well-ventilated warehouse, away from sources of heat and fire. Proper sealing is required to prevent contact with air, and it should always be kept separate from oxidants, edible chemicals, and acids. The storage area should have explosion-proof lighting and ventilation facilities and must not allow any mechanical equipment or tools that may cause sparks to prevent accidents. Leakage emergency treatment equipment and suitable storage materials must be readily available in the storage area.

[1] Yile Zhang. “Poly(propylene carbonate) networks with excellent properties: Terpolymerization of carbon dioxide, propylene oxide, and 4,4?-(hexafluoroisopropylidene) diphthalic anhydride.” e-Polymers 21 1 (2021): 511–519.
[2] C. D. Simone, D. A. Scola. “Phenylethynyl End-Capped Polyimides Derived from 4,4‘-(2,2,2-Trifluoro-1-phenylethylidene)diphthalic Anhydride, 4,4‘-(Hexafluoroisopropylidene)diphthalic Anhydride, and 3,3‘,4,4‘-Biphenylene Dianhydride: Structure?Viscosity Relationship.” Macromolecules 36 18 (2003): 6780–6790.
[3] MARYANNE MORES Patrick E C. Polyimidines. XI. Polyimidines from 3,3′,4,4′-benzophenonetetracarboxylic dianhydride and 4,4′-(hexafluoroisopropylidene) diphthalic anhydride[J]. Journal of Polymer Science Part A: Polymer Chemistry, 1990, 28 4: 811-823. DOI:10.1002/pola.1990.080280410.
[4] HUI WU  Hezhou L Hua Li. Synthesis and Properties of a High-Molecular-Weight Polyimide Based on 4, 4’-(hexafluoroisopropylidene) Diphthalic Anhydride[J]. Advanced Materials Research, 2012, 35 1: 742-746. DOI:10.4028/www.scientific.net/AMR.550-553.742.
[5] XU LIU. Molecular design of free volume structure in thermally rearranged polybenzoxazole membranes for gas separation studied by positron annihilation[J]. Journal of Polymer Science, 2024. DOI:10.1002/pol.20240229.
[6] GAOJIE WU. Design and preparation of thermoplastic polyimides with high transmittance based on 4,4′-(4,4′-isopropyldiphenoxy)bis(phthalic anhydride) (BPADA)[J]. European Polymer Journal, 2023. DOI:10.1016/j.eurpolymj.2022.111798.
[7] YOUNG NAM KIM, YONG CHAE JUNG*   Challenge for Trade-Off Relationship between the Mechanical Property and Healing Efficiency of Self-Healable Polyimide[J]. ACS Applied Materials & Interfaces, 2023. DOI:10.1021/acsami.3c12594.