Appeal No. 94-2414
Application 07/911,504
(d) washing said silica gel until the pH of the gel is at
least above about 3.
38. A silica gel having a specific surface area of between
about 200 and 600 m /g, average pore diameters in the range of2
about 50 to about 200 Angstroms and a narrow pore diameter
distribution wherein said distribution has a standard deviation
in pore diameter less than about 25 percent of the average pore
diameter,
wherein said silica gel is produced by a method comprising:
(a) mixing a solution of silicon tetrachloride and a water-
soluble, non-aqueous solvent with at least a stoichiometric
quantity of water containing fluoride ion to form a reactant
mixture and to hydrolyze the silicon tetrachloride to silica;
(b) permitting the silica to gel;
(c) aging the gel for about 4 hours;
(d) separately recovering the silica gel from the remainder
of the reactant mixture; and
(e) washing said silica gel until the pH of the gel is at
least above about 3.
The references of record relied upon by the examiner are:
Jacques et al. (Jacques) 4,504,595 Mar. 12, 1985
Hench et al. (Hench) 4,849,378 Jul. 18, 1989
Okamura et al. (Okamura) 4,975,405 Dec. 4, 1990
Colin et al. (Colin), “Introduction to Reversed-Phase High-
Performance Liquid Chromatography,” Journal of Chromatography,
141 (1977), pp. 289-312.
The appealed claims stand rejected under 35 U.S.C. § 103
over Jacques or Okamura in view of Colin and Hench.
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