Appeal No. 1999-1008
Application 08/713,905
claims 1 and 2 and claims 3 and 4 “do not therefore stand or fall together.” Thus, we decide this
appeal based on appealed claims 1 and 3 as representative of the respective grounds of rejection.
37 CFR § 1.192(c)(7) (1997).
We affirm both grounds of rejection.
Rather than reiterate the respective positions advanced by the examiner and appellants,
we refer to the examiner’s answer and to appellants’ brief for a complete exposition thereof.
Opinion
Considering first the ground of rejection of appealed claim 1 under § 103(a), the examiner
has taken the position that although Lehmann does not disclose the phosgenation of the specified
ether polyamine to obtain the corresponding ether (poly)isocyanate in vapor phase, it would have
been prima facie obvious to one of ordinary skill in this art to conducted the phosgenation of the
specific ether (poly)amines of Lehmann in the vapor phase from the combined teachings of this
reference, Joulak, Biskup and Bischof, which latter three references teach the phosgenation of
polyamines in the vapor phase (answer, page 5).
We find that Lehman would have disclosed to one of ordinary skill in this art that,
contrary to the teachings of the prior art which would expect ether cleavage products to be
formed during the phosgenation of ether (poly)amines to the corresponding isocyanate (col. 1,
lines 15-28 and 56-62), the phosgenation of the specified ether (poly)amines by known methods
will form desirable yields of the isocyanate with little if any cleavage (e.g., col. 1, lines 29-56 and
62-71, and col. 2, 16-33). Lehmann teaches a number of processes, specifying only that the
phosgenation process is conducted “at a temperature up to about 200° C” (Lehman claim 4), and
exemplifies carrying out the process in an inert solvent (Lehman Examples and Lehmann
claim 5). While Lehmann does not specifically so state, one of ordinary skill in this art would
have recognized from the reference that the processes of the reference are conducted under at
least atmospheric pressure, not in a vacuum. Joulak discloses that the phosgenation of aromatic
(poly)amines to the corresponding isocyanates can be conducted with an excess of phosgene in
the vapor phase with an inert, diluent carrier gas at a temperature which “advantageously ranges
from 250° to 500° C” and under pressure (cols. 1-4). The inert, diluent carrier gases used by
Joulak (col. 2, lines 46-51) correspond to several of the solvents used by Lehmann. Biskup
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