Appeal No. 2007-3827
Application 08/713,905
the conversion of monofunctional amines” (Joulak, col. 1, ll. 13-17;
emphasis supplied). Thus, Joulak would have disclosed to one of ordinary
skill in the art the phosgenation of aromatic polyamines to the corresponding
aromatic polyisocyanates can be conducted with an excess of phosgene in
the vapor phase in continuous manner with an inert, diluent carrier gas at a
temperature “advantageously ranges from 250° to 500° C” and under
pressure, with selective recovery of the diisocyanate followed by
purification (id., col. 1, l. 37, to col. 2, l. 52, col. 3, l. 55, to col. 4, l. 28, and
Examples 1 and 2). “The process . . . may be carried out under pressure, at
reduced pressure, or at atmospheric pressure, with no adverse consequences”
(id. col. 4, ll., 6-10). The selective recovery is conducted in inert solvent at a
temperature above the decomposition temperature of the carbamyl chloride
corresponding to the diisocyanate, and purification is “notably by
distillation” (id., e.g., col. 4, ll. 12-35). The solvents used for phosgenation
and product recovery include xylene, o-dichlorobenzene, and chlorobenzene
(id., e.g., col. 3, ll. 25-28, and col. 4, ll. 24-30).
We find Dr. Stutz testifies in his Declaration that, among other things,
I, as one skilled in the art of gas phase phosgenation, would not
consider the teachings of [Lehmann] to be applicable to the gas
phase phosgenation of ether (poly)amines because it was well
known at the time the present invention was made that
phosgenation of ether (poly)amines resulted in the formation of
a large quantity of unwanted product(s) due to cleavage.
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