9,9-Bis(4-aminophenyl)fluorene

9,9-Bis(4-aminophenyl)fluorene (FDA) is a fluorene derivative with two aminophenyl substituents on the 9-position. This compound has partial conjugation and can be utilized as a dopant-free organic hole-transporting material in inverted perovskite solar cells. Due to its diaminophenyl groups, FDA is commonly employed in synthesizing polyimides that possess high thermal and hydrolytic stability for optical fiber light guide coatings. Because the FDA is not fully aromatized, it is chosen to produce thermally stable transparent polyimides. Additionally, the polyimide derived from 9,9-bis(4-aminophenyl)fluorene can be further modified through Friedel-Crafts alkylation on the fluorene moiety, as the polyimide backbone remains chemically stable.

White powder

9,9-bis(4-aminophenyl)fluorene be used for preparation of high-strength material and high-temperature polymers.

The synthesis of 9,9-Bis(4-aminophenyl)fluorene can be carried out through the following stepwise procedure:
Prepare the reaction mixture:
Place 3.6 g of fluorenone (20 mmol), 7.2 g of aniline hydrochloride (55.6 mmol), 0.5 g of sodium bisulfite (4.8 mmol), 8.8 mL of aniline (96.4 mmol), and 6 mL of toluene in a 100 mL two-necked flask.
Ensure the reaction is conducted under nitrogen protection.
Add a water separator to the two-necked flask.

Begin the reaction:
Stir the reaction mixture and slowly increase the temperature to 120 °C.
Allow the reaction to continue for 30 minutes.
Separate the green liquid produced in the water separator.

Further reaction at elevated temperature:
Continue the reaction at 120 °C for an additional 3 hours.
Separate the water produced in the water separator.

Increase temperature and maintain reaction:
Slowly raise the temperature to 135 °C.
Keep the reaction at this temperature for 1.5 hours.

Monitor for completion:
Check the water separator for any further production of water.
Cease the reaction when no more water is produced in the water separator.

Cool down and adjust pH:
Allow the reacted material to cool to around 60 ℃.
Add 10 wt% potassium hydroxide solution to the reaction mixture.
Adjust the pH of the mixture to 9.
Stir the solution for 15 minutes while it is still hot.

Filtration and purification:
Filter the solution to remove any solid impurities.
Wash the filter cake with water.
Recrystallize the washed filter cake using 30 mL of toluene.
Filter the recrystallized product to obtain pure rice-white product.

Yield determination:
Weigh the obtained pure product, which should amount to 6.55 g.
Calculate the yield by dividing the obtained mass by the theoretical maximum mass and multiplying by 100%.
The yield of the pure rice-white product should be 94%.

4,4′-(9-Fluorenylidene)dianiline is a diamine.

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