Appeal No. 96-0920
Application 08/186,343
Both Bossler and appellants address the problem of replacing a highly toxic reducing agent
hydrazine with a less toxic reducing agent. Kirk-Othmer explicitly describes the toxicity of hydrazine and
states that, “Hydrazine is known to be highly toxic and readily absorbed by oral, dermal, or inhalation
exposure. It is irritating to the skin, eyes, and respiratory tract. Permanent damage to the cornea may
occur if the liquid is splashed into the eyes. At high doses it is a strong convulsant, but even low doses
may cause depression of the central nervous system. Death from acute exposure results from
convulsions, respiratory arrest, and cardiovascular collapse.” Appellants acknowledge the problem in3
the specification by employing a reducing agent, “significantly less toxic than hydrazine.” Specification,
page 2. Bossler likewise acknowledges the same problem at column 1, lines 34 - 35, and 58 - 60 stating
that hydrazine, “poses significant health and safety problems.” Based on the above considerations, we
conclude that both appellants and Bossler face the problem of finding a less toxic reducing agent than
hydrazine. Accordingly, the solution offered by Bossler to replace toxic hydrazine with a less toxic
reducing agent is reasonably pertinent to the particular problem with which appellants are involved.
Bossler solves the problem with a suggestion of numerous reducing agents in place of hydrazine.
However the preferred reducing agent is a hydrazine derivative, carbohydrazide. See column 23, lines
12 - 14, 37 - 38 and Examples 1- 4. We conclude that it was reasonable for the examiner to rely on the
teachings of Bossler to show the advantages of a less toxic reducing agent, i.e. carbohydrazide.
Based on the above considerations, we conclude that it would have been obvious to one of
3Encyclopedia of Chemical Technology, Kirk-Othmer, Third Edition, Volume 12, pages 760 -
761, John Wiley and Sons, New York 1980 (copy attached).
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