Fluorinated silica catalyst and preparation of aromatic/aliphatic nitriles in the presence thereof

Claim 1

A process for the preparation of the fluorinated siliceous catalyst comprising (i) adding an aqueous solution of sodium silicate to an aqueous solution of hydrofluoric acid, the temperatures of said solutions ranging from about -5° C. to about 15° C.; (ii) maintaining an amount of SiO 2 in the resulting reaction medium of less than about 15% by weight thereof, until the pH of said reaction medium attains a value of from about 3 to about 4.5; (iii) next permitting the mixture of reaction to gel, and comminuting the hydrogel which results into grain particles; then (iv) washing said grain particles to eliminate the soluble fluoride values therefrom; and (v) drying said washed grain particles at a temperature ranging from about 150° C. to 600° C.; said catalyst having a specific surface ranging from about 200 to about 300 m 2 /g, having a total pore volume ranging from about 1 to about 1.5 cm 3 /g, with an average pore diameter ranging from about 100 to about 200 Å, having an exchange pH of less than about 3 and with the fluorine content thereof bonded to the silica, expressed in F - , ranging from about 0.05 to about 2% by weight based upon the silica, and the sodium content thereof, expressed as Na 2 O, being less than about 1% by weight also based upon the silica.