Appeal No. 2007-0093 Page 4
Application No. 10/924,119
(“filtering the double-metal cyanide catalyst dispersion”). The isolated catalyst “is
preferably washed with an aqueous solution that contains additional organic complexing
agent.” Id., column 7, lines 42-44. Compare instant claim 12 (“washing the [double-
metal cyanide catalyst] filter cake with the at least one organic complexing ligand”).
Tert-butyl alcohol is a preferred complexing agent of Le-Khac ‘428. Id., column 4, line
13. Compare instant claim 15 (“where the organic complexing ligand is tert-butanol”).
Finally, the catalyst mixture is washed and filtered using a pressure filter, and then dried
in a vacuum oven. Id., column 8, Example 1, especially lines 41-48. See also Answer,
page 3.
Le-Khac ‘428 is described by the Examiner as teaching the “combining”,
“filtering”, “washing”, and “drying” of steps of claim 12, but not where these steps are
carried out in a filter press as required by the claim. See Answer, page 4, lines 1-2.
However, the Examiner states that Le-Khac6 teaches that the double-metal cyanide
catalyst can be isolated “by any convenient means, such as filtration.” Id., page 3; page
4. Hinney is further cited for its teaching “that a filter press is a suitable filtration
apparatus for separating a double metal cyanide catalyst from slurry (see column 7,
lines 6-37).” Id., page 4, lines 3-5. The Examiner concludes:
One having ordinary skill in the art at the time the invention was made
would have found it obvious to utilize a filter press, as taught by
Hinney et al., as the filtering, washing and mechanical removal apparatus
in the process of Le-Khac ‘428, since Le-Khac teach[es] that any
convenient means of separating the double metal cyanide catalyst may be
utilized, including filtration, and Hinney et al. teach that a filter press is a
6 The Examiner relies on Le-Khac ‘428 and Le-Khac ‘908, the latter which is incorporated by reference in
Le-Khac ‘428. In this instance where the Examiner cites “Le-Khac” for teaching that “any convenient
means” can be used to isolate the catalyst, the Examiner does not specify which Le-Khac is intended;
consequently, we assume both, especially in view of the incorporation by reference of Le-Khac ‘908 into
Le-Khac ‘428.
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