Appeal No. 2006-2694
Application No. 09/910,968
Cir. 1988). The reason for practicing the claimed subject matter may be
explicit from the prior art, In re Kotzab, 217 F.3d 1365, 1370, 55 USPQ2d
1313, 1317 (Fed. Cir. 2000) (citations omitted), or the
teaching, motivation or suggestion may be implicit from the
prior art as a whole, rather than expressly stated in the
references. The test for an implicit showing is what the
combined teachings, knowledge of one of ordinary skill in the
art, and the nature of the problem to be solved as a whole would
have suggested to those of ordinary skill in the art.
Id.
We agree with the Examiner that the teachings of Arhancet and
Higgins would have suggested the process recited in claims 1, 2, 9, and 18 to
one of ordinary skill in the art.
Arhancet discloses the preparation of vinyl aromatic monomers, i.e.,
unsaturated monomers such as styrene, under processing conditions
including vacuum distillation, in the presence of a nitroxyl inhibitor meeting
the formula of claim 2. (Arhancet, col. 2, ll. 8-52.) Arhancet notes that
styrene “is typically processed at temperatures between 95° and 125° C”
(Arhancet, col. 3, ll. 7-8), a temperature range overlapping the range recited
in claim 1. We take official notice that atmospheric pressure is 760 mm Hg;
therefore, Arhancet’s “vacuum distillation” reasonably appears to describe
distillation under a pressure of less than 760 mm Hg, as recited in claim 1.
Higgins discloses that a dinitrophenol inhibitor used in preparing
styrene monomer can be recycled from the product stream back to the initial
distillation column. (Higgins, Figure.) We agree with the Examiner that one
of ordinary skill practicing Arhancet’s process would have recognized that
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