Appeal No. 2007-0093 Page 3
Application No. 10/924,119
12. A process for preparing a double-metal cyanide catalyst comprising:
combining with a mixing nozzle in the presence of at least one
organic complexing ligand,
(a) at least one aqueous solution of at least one metal salt;
with
(b) at least one aqueous solution of at least one metal
cyanide salt;
to form a double-metal cyanide catalyst dispersion;
filtering the double-metal cyanide catalyst dispersion to obtain a
filter cake;
washing the filter cake at least once with the at least one organic
complexing ligand by a filter cake washing;
mechanically removing moisture in the washed filter cake; and
drying the filter cake
wherein the steps of filtering, washing and mechanically removing
are conducted in a filter press.
Obviousness under 35 U.S.C. § 103
Claims 12-19 stand rejected under 35 U.S.C. § 103(a) as obvious over
Le-Khac ‘4281 in view of Le-Khac ‘908,2 and further in view of Hinney,3 Heckl,4 and
Hoch.5
Le-Khac ‘428 teaches a method of preparing a double metal cyanide catalyst by
reacting aqueous solutions of a metal salt (such as zinc chloride) and a metal cyanide
salt (such as potassium hexacyanocobaltate). Le-Khac ‘428, column 3, lines 16-18, 30,
and 53; column 7, lines 11-13. Compare instant claims 12((a) and (b)), 13 (“the metal
salt is zinc chloride”), and 14 (“the metal cyanide salt is potassium hexacyano-
cobaltate”). The metal salt and metal cyanide salt are reacted in the presence of an
organic complexing agent. Id., column 7, lines 11-28. The resulting catalyst can be
isolated by simple filtration. Id., column 6, lines 26-28. Compare instant claim 12
1 Le-Khac, U.S. Patent No. 5,714,428, Feb. 3, 1998.
2 Le-Khac, U.S. Patent No. 5,482,908, Jan. 9, 1996.
3 Hinney, U.S. Patent No. 5,158,922, Oct. 27, 1992.
4 Heckl, U.S. Patent No. 6,387,282, May 14, 2002.
5 Hoch, U.S. Patent No. 6,103,786, Aug. 15, 2000.
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