Appeal No. 1998-0556
Application No. 08/367,418
zeolite beta catalyst as suggested by LaPierre in place of the
zeolite catalysts disclosed by Ward because higher liquid and
lower gas yields result.” From our perspective, however, this
obviousness conclusion is of highly questionable validity.
This is because Ward dewaxes feedstock by a cracking mechanism
in which selectivity is enhanced via the addition of ammonia
whereas, in contrast, LaPierre dewaxes feedstock by
isomerizing waxy paraffins “without substantial cracking” via
his zeolite beta catalyst. Under these circumstances, the
applied reference teachings would not have suggested replacing
the cracking catalyst in Ward’s process with the isomerization
catalyst of LaPierre particularly since the latter effects an
isomerization reaction without substantial cracking. For
analogous reasons, the applied references would not have
provided the artisan with a reasonable expectation that the
examiner’s proposed modification would be successful,
particularly since the ammonia-addition step of Ward’s process
functions to enhance cracking selectivity whereas LaPierre’s
zeolite beta catalyst functions to isomerize without
substantial cracking.
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