Appeal 2006-2675
Application 10/278,143
recognize that there are, as noted by Appellants, some similarities in the
reaction mechanisms of the two types of catalysts (Reply Br. 2), but this
does not convince us that the effective amounts of sulfur in the environment
of the reforming catalyst of Biswas are equivalent to the amounts to be in the
Van Brugge process. We particularly note that the catalysts discussed in
Biswas are alumina supported platinum catalysts whereas Van Brugge uses
beta zeolite, not alumina, and can use palladium as well as platinum.
Moreover, Appellants’ claim 1 is not limited to platinum. We also note that
Biswas indicates that other process parameters have an effect on the sulfur
tolerance of the catalyst. For instance, there is greater sulfur tolerance at
high pressures and low weight hourly space velocities (Biswas 213 ¶ 4). As
a further matter, Biswas discloses that when θ = 0.25, molecules can absorb
on the surface, but are prevented by sulfur structure from participating in
Langmuir-Hinshelwood reactions. It is only at θ = 0.5, a level above
Appellants’ 0.34 S atoms per Pt atom level, that the Pt becomes inert.
Appellants have not explained why only the θ < 0.2 disclosure is relevant.
Appellants also do not explain or show the calculations used to determine
that a catalyst with 1 wt% Pt and 0.05 wt% S will have 0.34 S atoms per Pt
atom. As a further matter, Appellants’ analysis overlooks the fact that the
claimed range includes the word “about” and, therefore, encompasses at
least some values below 0.05 wt% sulfur.
The evidence is insufficient to show that the “trace amount” disclosed
by Van Brugge excludes concentrations of sulfur at least about 0.05 wt%,
levels that, prima facie, are sufficiently low to be considered “trace
amounts” in the absence of convincing evidence to the contrary.
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