2 Methods of producing of hexamethylene bis(2-fluorenyldimethylammonium)
dibromide:
1. To a solution of 13.2 g (0.054 mole) of 9-bromofluorene in 200 ml of
acetonitrile was added 3.1 g (0.018 mole) of 1,6-bis(dimethylamino)hexane.
Heat was evolved and solid began to precipitate immediately. After the initial
reaction had subsided the mixture was refluxed for 3.5 h on a steam bath.
The solid was collected and recrystallized three times from propanol to give
10.66 g (89% of the theoretical yield based on alkylenediamine) of
hexamethylene bis(9-fluorenyldimethylammonium) dibromide, as white
crystals melting at 188°-189°C.
2. A mixture of 4.18 g (0.02 mole) of 2-dimethylaminofluorene and 1.22 g
(0.005 mole) of 1,6-dibromohexane was heated at 115°C for 24 h, after
which time 10 ml of dry dioxane was added and the mixture refluxed for an
additional 37 h. The solid was filtered off washed with hot acetonitrile and
twice recrystallized from propanol to give 0.45 g of hexamethylene bis(2-
fluorenyldimethylammonium) dibromide, melting at 220°-222°C.
