Appeal No. 94-2414
Application 07/911,504
The subject matter on appeal is directed to silica gel
defined in part by its method of preparation. Representative
claims 32, 34, 35 and 38 are reproduced below. To understand the
subject matter defined by product-by-process claims 32 and 34,
non-elected method claims 31 and 33 are also reproduced.
31. A method for producing silica gel suitable for use in
high pressure liquid chromatography comprising:
(a) mixing a solution of silicon tetrafluoride and a
solvent selected from the group consisting of C -C aliphatic
1 3
alcohols with a quantity of water sufficient to form a reactant
mixture having a mass ratio of water to silicon tetrafluoride of
between about 4:1 and 10:1 and to hydrolyze the silicon
tetrafluoride to silica;
(b) permitting the silica to gel;
(c) separately recovering the silica gel from the remainder
of the reactant mixture;
(d) washing said silica gel in water until the pH of the
gel is at least above about 3;
(e) drying said washed gel to obtain dry gel having
essentially one form of silanol moiety; and
(f) reacting said dried gel with a quantity of
organochlorosilane (sic, to bond the organochlorosilane) to said
dry gel.
32. Silica gel produced by the method of claim 31.
33. A method for producing silica gel suitable for use in
high pressure liquid chromatography comprising:
(a) mixing a solution of silicon tetrachloride and a water-
soluble, non-aqueous solvent with at least a stoichiometric
2
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