| abstract |
The invention relates to fluorine-containing silicas characterized in that their specific surface is between 200 and 300 m2 / g, their total pore volume is between 1 and 1.5 cm3 / g, the average pore diameter is between 100 and 200 Å, the exchange pH is less than approximately 3 and in that the fluorine content expressed in F - is between 0.05 and 2% by weight relative to the silica, the sodium content expressed in Na 2 0 being less than about 0.01 by weight relative to the silica.n n n The invention also relates to the application of these silicas to the preparation of aromatic or aliphatic nitriles from formamides, formanilides or amides. |