4-amino-2,6-di-tert-butylphenol Chemical Properties

Melting point:

103-107 °C(Solv: isooctane (540-84-1))

Boiling point:

309.3±42.0 °C(Predicted)

Density 

0.990±0.06 g/cm3(Predicted)

storage temp. 

Keep in dark place,Inert atmosphere,Room temperature

pka

13.95±0.40(Predicted)

4-amino-2,6-di-tert-butylphenol Usage And Synthesis

Application

4-Amino-2,6-di-tert-butylphenol, also known as 2,6-di-tert-butyl-4-aminophenol, is an important hindered phenolic antioxidant intermediate, widely used in rubber, plastics, pharmaceuticals, synthetic fibers, food, petroleum products, and cosmetics for heat oxidation resistance.

Synthesis

The general procedure for the synthesis of 4-amino-2,6-di-tert-butylphenol from 2,6-di-tert-butyl-4-nitrophenol is as follows: 3.6 g (14 mmol) of 4-nitro-2,6-bis(1,1-dimethylethyl)phenol (Literature Ref. J. Org. Chem. 1968, 33(1), 223-226) was dissolved in 60 mL of a mixed solvent of ethanol and methylene chloride (volume ratio 2:1) in a 250 mL Parr reaction vessel. (2:1 v/v) in a 250 mL Parr reaction flask. A catalytic amount of 10% Pd/C catalyst was added. The reaction mixture was stirred at 20°C and 20 psi hydrogen pressure for 2 hours. Upon completion of the reaction, the catalyst was removed by diatomaceous earth filtration and the filtrate was concentrated to dryness under reduced pressure. The resulting reddish brown powder was suspended in 30 mL of heptane, filtered and washed with the same volume of heptane. The resulting product was a salmon-colored powder in 50% yield (1.56 g). Melting point: 123-124 °C. NMR hydrogen spectrum (100 MHz, CDCl3, δ): 6.60 (s, 2H, aromatic hydrogen); 4.65 (wide s, 1H, hydroxyl hydrogen); 3.15 (wide s, 2H, amino hydrogen); 1.42 (s, 18H, tert-butyl hydrogen).

References

[1] Patent: US6335445, 2002, B1. Location in patent: Page column 72
[2] Patent: US6653312, 2003, B1. Location in patent: Page/Page column 45
[3] Patent: US6340700, 2002, B1. Location in patent: Page column 33
[4] Patent: US2003/78420, 2003, A1
[5] Patent: US6809088, 2004, B2