## Facts

- An earlier patent issued to Leonard Kaplan claimed a homogeneous liquid-phase catalytic process for making certain alkane diols and triols using hydrogen and carbon oxides with a rhodium carbonyl complex and a trialkanolamine borate.
- The earlier patent included claims requiring the process be conducted “in the presence of an organic solvent,” and dependent claims naming tetraglyme and sulfolane as individual solvents.
- The earlier patent’s specification described various solvents and included an example listing a tetraglyme/sulfolane mixed solvent, but no claim required a solvent mixture.
- Kaplan and Wellington Epler Walker later filed an application with a single claim directed to a similar process that specifically required a mixture of tetraglyme and sulfolane as the solvent system.
- The Board of Patent Appeals and Interferences rejected the later claim for double patenting under 37 C.F.R. § 1.196(b) and required a terminal disclaimer; the applicants refused.
- The applicants appealed the double-patenting rejection and terminal-disclaimer requirement.

## Issues

1. Whether the later claim requiring a tetraglyme/sulfolane solvent mixture was unpatentable for obviousness-type double patenting over the earlier patent’s claims.
2. Whether the earlier patent’s broad “organic solvent” claim “dominating” the later, narrower claim was sufficient to establish double patenting.
3. Whether unclaimed examples in the earlier patent’s disclosure could be treated as prior-art-like evidence to support a double-patenting rejection and require a terminal disclaimer.

## Decision

- The Federal Circuit reversed the board’s rejection.
- The court held the board improperly equated claim “domination” with double patenting.
- The court held the board improperly relied on unclaimed disclosure in the earlier patent as though it were prior art to show obviousness-type double patenting.
- The court concluded the later claim was patentably distinct from the earlier patent’s claims because the earlier claims did not require a solvent mixture.
- Because there was no proper double-patenting rejection, the terminal-disclaimer requirement was unwarranted.

## Legal Principles

- Statutory double patenting bars a later claim to the same invention; obviousness-type double patenting bars a later claim that is not patentably distinct from an earlier claim and would extend the right to exclude.
- Obviousness-type double patenting is evaluated by comparing the claims of the earlier patent with the claims of the later application; unclaimed disclosure in the earlier specification does not control the analysis.
- A broad earlier claim that reads on a narrower later claim (“domination”) does not, by itself, establish double patenting; a narrower improvement may be separately patentable if patentably distinct from the earlier claims.
- A terminal disclaimer is a remedy for a valid obviousness-type double-patenting problem and cannot be demanded absent a legally supported double-patenting rejection.

## Conclusion

The Federal Circuit set aside a double-patenting rejection where the board relied on claim domination and an unclaimed example in the earlier patent’s specification; the later claim to a specific tetraglyme/sulfolane solvent mixture was patentably distinct from the earlier patent’s claims, making a terminal disclaimer unnecessary.


In re Kaplan, 789 F.2d 1574 (Fed. Cir. 1986)