Appeal No. 1996-0823
Application No. 08/217,189
claims 1 through 4, 8 through 14, 16, and 18 preclude the steps described by Lang where
precipitation and work-up of product are carried out with acetone.
According to the examiner, a person having ordinary skill in the art would have
recognized that Lang's "intervening" work-up steps are not necessary for the recovery of
N-hydroxypropyl-chitosan. The examiner argues that it would have been obvious to forego
Lang's "intervening" steps, which precede drying and where precipitation and work-up of
product are carried out with acetone, and "to proceed directly to drying" of the desired
product. See the Examiner's Answer, page 5, lines 13 through 23. The examiner argues
that a person having ordinary skill in the art, by thus modifying the process of Lang set in
forth in column 10, example 4, would have arrived at the instantly claimed process. We
disagree.
On reflection, we believe that the examiner's proposed modification of the prior art
process relies on the impermissible use of hindsight. The only reason, suggestion,
or motivation to omit Lang's intervening work-up steps and "to proceed directly to drying"
stems from appellants' specification and not the cited prior art. In contrast with appellants'
specification and claims, Lang requires the intervening work-up steps which
precede drying and where precipitation and work-up of product are carried out with
acetone. Accordingly, we reverse the examiner's rejection of claims 1 through 4, 8 through
14, 16, and 18 under 35 U.S.C. § 103.
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