Appeal No. 95-3827
Application No. 08/031,793
with hydrogen in the presence of a hydrogenation catalyst
(p.2). The conditions of the hydrogenation treatment are as
follows (p.3):
(1) Pressure: from 1 to 300 bar, preferably from 10 to
200 bar and more preferably from 20 to 60 bar;
(2) Temperature: from 20E to 400EC, preferably from 70E
to 320EC; and
(3) Time: from 10 minutes to 2 hours.
Compare appellants' specification, p.3, lines 8-13 ("the amine
corresponding to the desired isocyanate is phosgenated and the
resultant isocyanates or isocyanate mixtures are subjected to
a hydrogen treatment at a pressure of from about 3 to about
150 bar and a temperature of 100 to 180EC in the presence of a
catalyst for from about 15 minutes to about 4 hours").
Suitable catalysts include platinum and palladium (p.3;
compare appellants' specification, p.3, lines 20-24).
According to Bruchmann, the disclosed diaminodiphenylmethanes
are reacted with phosgene to produce the corresponding
diphenylmethane diisocyanates (p.1). The process disclosed in
Bruchmann is said to avoid any discoloration of the isosyanate
produced (p.2, lines 6-9). See Answer, p.2.
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