Réaction #59224

Équation de réaction

4,4′-dihydroxydiphenyl ether

phosgene

sodium hydroxide

p-tert.-butylphenol

sodium hydroxide

n-ethylpiperidine

bisphenol A

→

bisphenol A 4,4′-dihydroxydiphenyl ether

Solvants

methylene chloride

water

Conditions de réaction

Traitement

1. 1
   workup.ADDITIONwas added during the phosgenation
2. 2
   workup.ADDITIONis added as catalyst
3. 3
   AutreThe aqueous phase is separated off
4. 4
   Lavagewashed with distilled water until neutral and free of salt
5. 5
   AutrePrecipitation of the polymer in methanol
6. 6
   Séchagedrying yield 19.0 g of polycarbonate

Mode opératoire

131 ml of methylene chloride are added to a solution, rendered inert with nitrogen, of 0.809 g (0.004 mol.) of 4,4′-dihydroxydiphenyl ether and 17.35 g (0.076 mol.) of bisphenol A as well as 7.04 g (0.176 mol.) of sodium hydroxide in 131 ml of water. In a one-step procedure, 0.36 g (0.0024 mol. or 3.0 mol. % relative to bisphenol) of p-tert.-butylphenol (BUP) are added as chain terminator. At a pH value of 14 and at room temperature, 11 ml (15.8 g, 0.16 mol.) of phosgene are added in the course of 10 minutes. In order to prevent the pH value from falling below 12, 25% sodium hydroxide solution was added during the phosgenation. When the phosgenation is complete, and after rinsing with nitrogen, 0.11 ml (0.0008 mol., 1 mol. % relative to bisphenol) of n-ethylpiperidine is added as catalyst, and stirring is then carried out for one hour. The aqueous phase is separated off, and the organic phase is acidified with phosphoric acid and washed with distilled water until neutral and free of salt. Precipitation of the polymer in methanol and drying yield 19.0 g of polycarbonate.

Source