Appeal No. 1999-1180
Application No. 08/751,557
The subject matter on appeal relates to a method for
preparing difluoromethane by reacting hydrogen with
dichlorodifluoromethane and/or monochlorodifluoromethane in the
presence of a palladium-based catalyst including Pd and at least
one additional metal selected from the group consisting of
vanadium, zirconium, calcium, magnesium, niobium, and tantalum.
(Appeal brief, page 3.) Further details of this appealed
subject matter are recited in illustrative claims 1 and 6
reproduced below:
1. A method for preparing difluoromethane
comprising reacting dichlorodifluoromethane and/or
monochlorodifluoromethane with hydrogen in the
presence of a palladium-based catalyst, wherein the
palladium-based catalyst is a catalyst in which at
least one additional metal selected from the group
consisting of vanadium, zirconium, calcium, magnesium,
niobium and tantalum is added to palladium.
6. The method according to claim 1, wherein the
molar ratio of hydrogen to the dichlorodifluoromethane
and/or monochlorodifluoromethane is from 1 to 10.
The examiner relies on the following prior art references
as evidence of unpatentability:
Morikawa et al. 1-242536 Sep. 27, 1989
(Morikawa)(published JP
patent application)
Moore et al. 0,508,660 A1 Oct. 14, 1992
(Moore)(published EP
patent application)
2
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