Wednesday, December 29, 2004

Stephens v. Tech International

The CAFC decision is nominally about exceptional case under 35 USC 285. However, it gets into the distinction (or lack thereof) between chromium trioxide and chromic acid.

On the issue of acid, the CAFC cites Merck v. Teva, 347 F.3d 1367 (CAFC 2003). However, a more pertinent issue here concerns the fact that chromium trioxide itself is a solid, comprising linear chains of tetrahedrally coordinated Cr(VI). Although there is no shortage of texts that equate "chromium trioxide" and "chromic acid," a more precise definition is along the lines:

Chromic Acid: an aqueous solution of chromium trioxide (CrO3) or a commercial solution containing chromic acid, dichromic acid (H2Cr2O7), or trichromic acid (H2Cr3O10).

Chromium trioxide itself contains no protons and is not a Bronsted acid. Its chemistry is modified by contact with acids (eg, acetic acid) or bases (eg, pyridine) but those modified forms should not be equated with chromium trioxide itself.

[My interest in chromium trioxide arises from a debate, now more than 50 years old, as to whether or not chromium trioxide itself intercalates graphite. There is no doubt that chromium trioxide in solution intercalates (although not as chromium trioxide), but there is much doubt that chromium trioxide itself (ie, the linear polymer, with only Cr(VI)) intercalates. There are patents for chromium trioxide "in" graphite as a battery cathode and as an organic oxidant. In the patent world, the emphasis is on providing a valid recipe to do something useful, and the issue of whether or not the scientific description is accurate does not come up. Recall also buckminsterfullerene (C60), the synthesis of which was described more than a year before the work of Smalley and Kroto. This issue is also present in the Stephens case. Whether or not chromium trioxide and chromic acid are the same (they really are NOT), they are different from chromates and dichromates.]


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