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The claims-at-issue are directed to a process for producing purified benzene requiring a final step of fractionalizing to form a purified benzene product comprising at least about 80% benzene.  The district court granted summary judgment of non-infringement, inherently construing “fractionating” to mean conventional distillation (based on differences in boiling points) and finding that Shell’s process uses extraction (based on solubility). 

On appeal, Netzer argued that “fractionating” means separating a mixture into fractions, no matter what processes are used to do so, and thus does not exclude extraction.  The Federal Circuit, however, agreed with the district court, because the specification repeatedly and consistently uses “fractionating” to mean separating based on differences in boiling point and because the patentee made clear and unmistakable statements in the intrinsic record distinguishing the invention from and disclaiming conventional extraction methods that produce 99.9% pure benzene. 

The court further held that, under this construction, summary judgment of non-infringement was proper.  First, the portion of the Shell process that used distillation only produced 57% pure benzene, which was less than that required by the claim.  Further, the doctrine of equivalents is unavailable to Netzer, because he disclaimed the Sulfanone process (the process also used by Shell) during prosecution.  Accordingly, the court affirmed the decision of the district court.

David Netzer Consulting Engineer LLC v. Shell Oil Company, Case No. 2015-2086 (May 27, 2016); Opinion by: Lourie, joined by Prost and Taranto; Appealed From: United States District Court for the Southern District of Texas, Hughes, J. Read the full opinion here.

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