Appeal No. 96-2808
Application 08/102,708
Buc discloses blending a branched ether such as isopropyl ether, t-butyl ether, methyl-t-butyl ether
or methyl-t-amyl ether with gasoline or motor fuel for the purpose of reducing knock and increasing octane
number (col. 1, lines 6-10 and 34-47). Bruderreck discloses blending a mixture of branched ethers
(methyl-t-butyl ether, isopropyl-t-butyl ether and sec-butyl-t-butyl ether) with motor fuel to, inter alia,
improve octane number (abstract; col. 2, lines 38-57; col. 4, lines 24-42). Bruderreck states that the "use
of ether ... mixtures is an improvement over the use of a single ether" (col. 3, lines 35-37). Leum discloses
a method of preparing a mixture of branched ethers by contacting one or more C -C primary or
1 12
secondary alcohols such as methanol, ethanol and isopropanol with one or more C -C branched olefins
4 16
such as isobutylene and isoamylene (col. 1, lines 10-49; col. 4, lines 5-9; table in col. 3). However, Leum
does not teach or suggest any use for his ether product. The examiner concluded that “[h]aving the prior
art before him the artisan in the art would have been motivated to substitute Leum ether mixture for
Bruderreck ether mixture with the reasonable expectation [that] the ether mixture will exhibit the same or
similar properties because Leum ether mixture encompasses Bruderreck ether mixture” (answer: paragraph
bridging pp. 4-5).
We find that the examiner has not established a prima facie case. Bruddereck discloses blending
three specific alkyl-t-butyl ethers together to form a mixture which is then mixed with motor fuel. We find
that there is no teaching or suggestion in the art of record which would have motivated a person having
ordinary skill in the art to substitute Leum’s particular method for preparing ether mixtures for Bruderreck’s
method to arrive at appellants’ method set forth in claims 21-26, 29 and 30. The examiner appears to rely
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