Appeal 1997-1635
Application 08/319,667
cation-exchange resin. We know that the "strongly acidic
cation-exchange resin" contains sulfonic acid groups because
Japan describes the use of "strongly acid cation-exchange
resins having sulfonic acid groups" (Japan, page 4, second
paragraph). Accordingly, it can be said that an organic
sulfonic acid is added to the impure methacrylic acid.
Thereafter, tetraethylene pentamine (an amine with at least
one primary amino group) is added to the treated methacrylic
acid followed by distillation.
Actual Example 21 (Japan, page 12) describes an
embodiment which does not fall precisely within the scope of
claim 1. Concentrated sulfuric acid is added to impure
methacrylic acid. Distillation recovers a desired product to
which is added tetraethylene pentamine, followed by another
distillation. The difference between claim 1 and Actual
Example 21 is that concentrated sulfuric acid is not an
organic sulfonic acid. However, on page 4, Japan tells us
that sulfuric acid, benzenesulfonic acid and p-toluenesulfonic
acid, the latter two being organic sulfonic acids, may be used
in the process. One skilled in the art would have no
difficulty finding it entirely obvious to substitute either
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