In the polymerisation procedure below naphthalene is dissolved in nitrobenzene and stereometric excess of FeCl3 is added.
My understanding is is the coupling results from the FeCl3 and the nitrobenzene is only a solvent. Is that correct? What other solvent could be used
preferably a more OTC one? Perhaps nitrotoluene.
The procedure: "To a solution of naphthalene (10.2 g, 80 mmol) in nitrobenzene (137 ml) was added FeCl3 (28.6 g, 176 mmol) with vigorous stirring at
room temperature under nitrogen. The solution was stirred at 90 °C for 1h and then at 150 °C for 24 h. The mixture was poured into
methanol (686 ml) containing a small amount of concentrate HCl (3 ml). The precipitate was filtered and washed with methanol. It was dispersed in
chloroform (200 ml). The precipitate was filtered, washed with chloroform, and dried at 120 °C for 3 h under reduced pressure. PNP (8.3 g, 83%) was
obtained as the black powder"
From page 6 of Attachment: PNP-pourmousavi2017.pdf (1.9MB) This file has been downloaded 273 timesunionised - 19-3-2020 at 12:25
Nitrobenzene may act as an oxidising agent.mackolol - 19-3-2020 at 13:12
Similar reaction is with AlCl3 and acid but this creates naphthalene dimer - perylene. wg48temp9 - 20-3-2020 at 01:30
Apparently its called a Scholl coupling or Scoll oxidative coupling. I did wounder were the H went but as the procedure uses slight excess of 2x
stoichiometric amount of FeCl3 I assumed the FeCl3 was the oxidiser. Perhaps the nitrobenzene is too.
I found a paper discussing the mechanism see Attachment: scholl-grzybowski2013.pdf (2.4MB) This file has been downloaded 315 times
