Full opinion text
LOURIE, Circuit Judge. Diane M. Dillon, assignor to Union Oil Company of California, appeals the November 25, 1987, decision of the Board of Patent Appeals and Interferences (Board) of the United States Patent and Trademark Office (PTO), Appeal No. 87-0944, rejecting claims 2-14, 16-22, and 24-37, all the remaining claims of patent application Serial No. 671,570 entitled “Hydrocarbon Fuel Composition.” We affirm the rejection of all of the claims. The Invention Dillon’s patent application describes and claims her discovery that the inclusion of certain tetra-orthoester compounds in hydrocarbon fuel compositions will reduce the emission of solid particulates (i.e., soot) during combustion of the fuel. In this appeal Dillon asserts the patentability of claims to hydrocarbon fuel compositions containing these tetra-orthoesters, and to the method of reducing particulate emissions during combustion by combining these esters with the fuel before combustion. Claim 2 is the broadest composition claim: 2. A composition comprising: a hydrocarbon fuel; and a sufficient amount of at least one orthoester so as to reduce the particulate emissions from the combustion of the hydrocarbon fuel, wherein the orthoester is of the formula: wherein R5, Rs, R7, and R8, are the same or different monovalent organic radical comprising 1 to about 20 carbon atoms. The broadest method claim is claim 24: 24. A method of reducing the particu- late emissions from the combustion of a hydrocarbon fuel comprising com-busting a mixture of the hydrocarbon fuel and a sufficient amount of at least one orthoester so as to reduce the particulate emissions, wherein the or-thoester is of the formula: wherein R5, R(¡, R7, and Rg, are the same or different monovalent organic radical comprising 1 to about 20 carbon atoms. The other claims contain additional limitations and thus are narrower in scope. The tetra-orthoesters are a known class of chemical compounds. It is undisputed that their combination with hydrocarbon fuel, for any purpose, is not shown in the prior art, and that their use to reduce particulate emissions from combustion of hydrocarbon fuel is not shown or suggested in the prior art. The Rejection The Board held all of the claims to be unpatentable on the ground of obviousness, 35 U.S.C. § 103, in view of certain primary and secondary references. As primary references the Board relied on two Sweeney U.S. patents, 4,390,417 (’417) and 4,395,267 (’267). Sweeney ’417 describes hydrocarbon fuel compositions containing specified chemical compounds, viz., ketals, acetals, and tri-orthoesters, used for “dewatering” the fuels, particularly diesel oil. Sweeney '267 describes three-component compositions of hydrocarbon fuels heavier than gasoline, immiscible alcohols, and tri-or-thoesters, wherein the tri-orthoesters serve as cosolvents to prevent phase separation between fuel and alcohol. The Board explicitly found that the Sweeney patents do not teach the use of the tetra-orthoesters recited in appellant’s claims. The Board cited Elliott U.S. Patent 3,903,006 and certain other patents, including Howk U.S. Patent 2,840,613, as secondary references. Elliott describes tri-or-thoesters and tetra-orthoesters for use as water scavengers in hydraulic (non-hydrocarbon) fluids. The Board stated that the Elliott reference shows equivalence between tetra-orthoesters and tri-orthoesters, and that “it is clear from the combined teachings of these references ... that [Dillon’s tetra-orthoesters] would operate to remove water from non-aqueous liquids by the same mechanism as the orthoesters of Sweeney.” The Board stated that there was a “reasonable expectation” that the tri- and tetraorthoester fuel compositions would have similar properties, based on “close structural and chemical similarity” between the tri- and tetra-orthoesters and the fact that both the prior art and Dillon use these compounds as “fuel additives.” The Commissioner argues on appeal that the claimed compositions and method “would have been prima facie obvious from combined teachings of the references.” On this reasoning, the Board held that unless Dillon showed some unexpected advantage or superiority of her claimed tetra-orthoes-ter fuel compositions as compared with triorthoester fuel compositions, Dillon’s new compositions as well as her claimed method of reducing particulate emissions are un-patentable for obviousness. It found that no such showing was made. The Issue The issue before this court is whether the Board erred in rejecting as obvious under 35 U.S.C. § 103 claims to Dillon’s new compositions and to the new method of reducing particulate emissions, when the additives in the new compositions are structurally similar to additives in known compositions, having a different use, but the new method of reducing particulate emissions is neither taught nor suggested by the prior art. The Broad Composition Claims Claim 2, the broadest composition claim, comprises a hydrocarbon fuel and an amount of tetra-orthoester sufficient to reduce the particulate emissions from the combustion of the hydrocarbon fuel. The other composition claims contain various limitations including a minimum amount of emission reduction to be achieved (claim 3), percentages of ester in the fuel (claims 4, 5, 16, 20, 21), use of different esters (claims 6-10, 17-19), use of different fuels (claims 11-14, 22), and the requirement that the composition be essentially free of alcohol (claims 36, 37). The Board stated in its opinion that, to the extent that appellant had not chosen to separately argue the patentability of the appealed claims, “they stand or fall together,” citing In re Kaslow, 707 F.2d 1366, 1376, 217 USPQ 1089, 1096 (Fed.Cir.1983). We agree with the Board except as noted briefly below. It is not the practice of this court to review claims that an applicant has not separately argued at the Board level, because, inter alia, we lack the benefit of the Board’s reasoned decision on the separate patentability of those claims. Id. at 1376, 217 USPQ at 1096; In re Herbert, 461 F.2d 1390, 1391, 59 CCPA 1091, 174 USPQ 259, 260 (CCPA 1972). We will therefore review only the merits of the composition claims, as did the Board. The Board found that the claims to compositions of a hydrocarbon fuel and a tetraorthoester were prima facie obvious over Sweeney ’417 and ’267 in view of Elliott and Howk. We agree. Appellant argues that none of these references discloses or suggests the new use which she has discovered. That is, of course, true, but the composition claims are not limited to this new use; i.e., they are not physically or structurally distinguishable over the prior art compositions except with respect to the orthoester component. We believe that the PTO has established, through its combination of references, that there is a sufficiently close relationship between the tri-or-thoesters and tetra-orthoesters (see the cited Elliott and Howk references) in the fuel oil art to create an expectation that hydrocarbon fuel compositions containing the tetra-esters would have similar properties, including water scavenging, to like compositions containing the tri-esters, and to provide the motivation to make such new compositions. Howk teaches use of both tri- and tetra-orthoesters in a similar type of chemical reaction. Elliott teaches their equivalence for a particular practical use. Our case law well establishes that such a fact situation gives rise to a prima facie case of obviousness. See In re Shetty, 566 F.2d 81, 85, 195 USPQ 753, 755-56 (CCPA 1977); In re Albrecht, 514 F.2d 1385, 1388, 185 USPQ 590, 593 (CCPA 1975); In re Murch, 464 F.2d 1051, 1054, 59 CCPA 1277, 175 USPQ 89, 91 (CCPA 1972); In re Hoch, 428 F.2d 1341, 1343, 57 CCPA 1292, 166 USPQ 406, 409 (CCPA 1970). Appellant cites In re Wright, 848 F.2d 1216, 1219, 6 USPQ2d 1959, 1961 (Fed.Cir.1988), for the proposition that a prima facie case of obviousness requires that the prior art suggest the claimed compositions’ properties and the problem the applicant attempts to solve. The earlier panel opinion in this case, In re Dillon, 892 F.2d 1554, 13 USPQ2d 1337 (now withdrawn), in fact stated “a prima facie case of obviousness is not deemed made unless both (1) the new compound or composition is structurally similar to the reference compound or composition and (2) there is some suggestion or expectation in the prior art that the new compound or composition will have the same or a similar utility as that discovered by the applicant.” Id. at 1560, 13 USPQ2d at 1341 (emphasis added). This court,. in reconsidering this case in banc, reaffirms that structural similarity between claimed and prior art subject matter, proved by combining references or otherwise, where the prior art gives reason or motivation to make the claimed compositions, creates a prima facie case of obviousness, and that the burden (and opportunity) then falls on an applicant to rebut that prima facie case. Such rebuttal or argument can consist of a comparison of test data showing that the claimed compositions possess unexpectedly improved properties or properties that the prior art does not have {In re Albrecht, 514 F.2d 1389, 1396, 185 USPQ 585, 590 (CCPA 1975); Murch, 464 F.2d at 1056, 175 USPQ at 92), that the prior art is so deficient that there is no motivation to make what might otherwise appear to be obvious changes (Albrecht, 514 F.2d at 1396, 185 USPQ at 590; In re Stemniski, 444 F.2d 581, 58 CCPA 1410, 170 USPQ 343 (CCPA 1971); In re Ruschig, 343 F.2d 965, 52 CCPA 1238, 145 USPQ 274 (CCPA 1965)), or any other argument or presentation of evidence that is pertinent. There is no question that all evidence of the properties of the claimed compositions and the prior art must be considered in determining the ultimate question of patentability, but it is also clear that the discovery that a claimed composition possesses a property not disclosed for the prior art subject matter, does not by itself defeat a prima facie case. Shetty, 566 F.2d at 86, 195 USPQ at 756. Each situation must be considered on its own facts, but it is not necessary in order to establish a prima facie case of obviousness that both a structural similarity between a claimed and prior art compound (or a key component of a composition) be shown and that there be a suggestion in or expectation from the prior art that the claimed compound or composition will have the same or a similar utility as one newly discovered by applicant. To the extent that Wright suggests or holds to the contrary, it is hereby overruled. In particular, the statement that a prima facie obviousness rejection is not supported if no reference shows or suggests the newly-discovered properties and results of a claimed structure is not the law. Under the facts we have here, as described above, we have concluded that a prima facie case has been established. The art provided the motivation to make the claimed compositions in the expectation that they would have similar properties. Appellant had the opportunity to rebut the prima facie case. She did not present any showing of data to the effect that her compositions had properties not possessed by the prior art compositions or that they possessed them to an unexpectedly greater degree. She attempted to refute the significance of the teachings of the prior art references. She did not succeed and we do not believe the PTO was in error in its decision. Appellant points out that none of the references relates to the problem she confronted, citing In re Wright, and that the combination of references is based on hindsight. It is clear, however, that appellant’s claims have to be considered as she has drafted them, i.e., as compositions consisting of a fuel and a tetra-orthoester, and that Sweeney ’417 and ’267 describe the combination of a liquid fuel with a related compound, a tri-orthoester. While Sweeney does not suggest appellant’s use, her composition claims are not limited to that use; the claims merely recite compositions analogous to those in the Sweeney patents, and appellant has made no showing overcoming the prima facie presumption of similar properties for those analogous compositions. The mention in the appealed claims that the amount of orthoester must be sufficient to reduce particulate emissions is not a distinguishing limitation of the claims, unless that amount is different from the prior art and critical to the use of the claimed composition. See In re Reni, 419 F.2d 922, 925, 57 CCPA 857, 164 USPQ 245, 247 (CCPA 1970). That is not the case here. The amount of ester recited in the dependent claims can be from 0.05-49%, a very broad range; a preferred range is .05-9%, compared with a percentage in Sweeney ’417 approximately equimo-lar to the amounts of water in the fuel which the ester is intended to remove (.01-5%). Appellant attacks the Elliott patent as non-analogous art, being in the field of hydraulic fluids rather than fuel combustion. We agree with the PTO that the field of relevant prior art need not be drawn so narrowly. As this court stated in In re Deminski, 796 F.2d 436, 442, 230 USPQ 313, 315 (Fed.Cir.1986) (quoting In re Wood, 599 F.2d 1032, 1036, 202 USPQ 171, 174 (CCPA 1979)): [t]he determination that a reference is from a nonanalogous art is therefore two-fold. First, we decide if the reference is within the field of the inventor’s endeavor. If it is not, we proceed to determine whether the reference is reasonably pertinent to the particular problem with which the inventor was involved. Following that test, one concerned with the field of fuel oils clearly is chargeable with knowledge of Sweeney ’417, which discloses fuel compositions with tri-orthoes-ters for dewatering purposes, and chargeable with knowledge of other references to tri-orthoesters, including for use as dewa-tering agents for fluids, albeit other fluids. These references are “within the field of the inventor’s endeavor.” Moreover, the statement of equivalency between tri- and tetra-orthoesters in Elliott is not challenged. We therefore conclude that Elliott is not excludable from consideration as non-analogous art. It is evidence that supports the Board’s holding that the prior art makes the claimed compositions obvious, a conclusion that appellant did not overcome. Appellant urges that the Board erred in not considering the unexpected results produced by her invention and in not considering the claimed invention as a whole. The Board found, on the other hand, that no showing was made of unexpected results for the claimed compositions compared with the compositions of Sweeney. We agree. Clearly, in determining patentability the Board was obligated to consider all the evidence of the properties of the claimed invention as a whole, compared with those of the prior art. However, after the PTO made a showing that the prior art compositions suggested the claimed compositions, the burden was on the applicant to overcome the presumption of obviousness that was created, and that was not done. For example, she produced no evidence that her compositions possessed properties not possessed by the pri- or art compositions. Nor did she show that the prior art compositions and use were so lacking in significance that there was no motivation for others to make obvious variants. There was no attempt to argue the relative importance of the claimed compositions compared with the prior art. See In re May, 574 F.2d 1082, 1092-95, 197 USPQ 601, 609-11 (CCPA 1978). Appellant’s patent application in fact included data showing that the prior art compositions containing tri-orthoesters had equivalent activity in reducing particulate emissions (she apparently was once claiming such compositions with either tri-or-thoesters or tetra-orthoesters). She asserts that the examiner used her own showing of equivalence against her in violation of the rule of In re Ruff, 256 F.2d 590, 596, 45 CCPA 1037, 118 USPQ 340, 346 (CCPA 1958). While we caution against such a practice, it is clear to us that references by the PTO to the comparative data in the patent application were not employed as evidence of equivalence between the tri- and tetra-orthoesters; the PTO was simply pointing out that the applicant did not or apparently could not make a showing of superiority for the claimed tetra-ester compositions over the prior art tri-ester compositions. Other Claims As indicated above, the Board held that it would not consider the appealed claims separately, since appellant did not. Nonetheless, appellant, in her brief before the Board, did refer generally to claims directed to fuels essentially free of alcohol (Brief at 32, J.App. at 122), and the Board, in its decision, did respond, stating that no objective evidence was presented to establish any different or unexpected results from limiting the amount of alcohol to less than 1%, In re Dillon, No. 87-0944, slip op. at 9-10 (Bd.Pat.App. & Int. Nov. 25, 1987). We agree. Moreover, Sweeney ’417 describes compositions which also contain less than 1% alcohol, so there is no real distinction in the claims over the prior art. Appellant also argued in her brief to the Board that she “must contest” the examiner’s position concerning claims limited to no more than 5 or 9 volume percent added orthoester, mentioning claims 16-21 and 27-31. The Board did not expressly deal with these claims, but it is clear to us that, since these limits do not result in an amount of ester different from that disclosed to remove water in Sweeney ’417, and no criticality is shown for these limitations, the subject matter of these claims has not been shown to have been nonob-vious. Regarding the method claims, the Commissioner urges affirmance, citing In re Durden, 763 F.2d 1406, 226 USPQ 359 (Fed.Cir.1985), for the proposition that even “substitution of an unobvious starting material into an old process does not necessarily result in an unobvious process.” The PTO has, as the Commissioner urges here, applied Durden regularly to claims to processes of making and processes of using, on the ground that the type of step involved in the claimed process is not novel. We make no judgment as to the patenta-bility of claims that Dillon might have made and properly argued to a method directed to the novel aspects of her invention, except to question the lack of logic in a claim to a method of reducing particulate emissions by combusting. Suffice it to say that we do not regard Durden as authority to reject as obvious every method claim reading on an old type of process, such as mixing, reacting, reducing, etc. The materials used in a claimed process as well as the result obtained therefrom, must be considered along with the specific nature of the process, and the fact that new or old, obvious or nonobvious, materials are used or result from the process are only factors to be considered, rather than conclusive indicators of the obviousness or nonob-viousness of a claimed process. When any applicant properly presents and argues suitable method claims, they should be examined in light of all these relevant factors, free from any presumed controlling effect of Durden. Durden did not hold that all methods involving old process steps are obvious; the court in that case concluded that the particularly claimed process was obvious; it refused to adopt an unvarying rule that the fact that nonob-vious starting materials and nonobvious products are involved ipso facto makes the process nonobvious. Such an invariant rule always leading to the opposite conclusion is also not the law. Thus, we reject the Commissioner’s argument that we affirm the rejection of the method claims under the precedent of Durden. However, appellant did not argue in her brief the separate patentability of her method claims. The statement in her brief to the Board that “the invention ‘as a whole’ includes the property of the claimed compositions—which property is taken advantage of in the method claims” (Brief at 22, J.App. at 112) is not such a separate argument, since it implies more an added argument for the patentability of the composition claims than an argument that, even if the claimed compositions are found to have been obvious, the claimed methods were nonobvious for particularly stated reasons. Moreover, no such reasons were particularly stated by Dillon. We will therefore not analyze these claims separately and affirm the Board’s rejection on that basis. The Dissent The strong assertions by the dissent and its treatment of some of the case law impel us to make the following comments: The dissent argues that our decision is “contrary to the weight and direction of ... precedent, as embodied in over three decades of decision”; that we are resurrecting the “Hass-Henze” Doctrine, which was “discarded thirty years ago”; and that our holding today “changes what must be proved in order to patent a new chemical compound and composition and its new use, and thus changes what is patentable.” We have done none of the above. What we have done is to decide the case before us on the basis of long-established principles which had provided a stable understanding of the chemical patent law until the issuance of the original panel opinion in this case which we have now vacated. Our intent is to restore the law to its state existing before that panel opinion. The length of the dissent and the number of cases it discusses may convey the impression that the weight of past jurisprudence is contrary to our holding today. That is not the case. The cited cases are simply not controlling on the facts of the present case or they are not contrary. Many do not deal with the requirements of a prima facie case. Some involve process claims, not compound or composition claims. Others are not pertinent for other reasons. In brief, the cases establish that if an examiner considers that he has found prior art close enough tq the claimed invention to give one skilled in the relevant chemical art the motivation to make close relatives (ho-mologs, analogs, isomers, etc.) of the prior art compound(s), then there arises what has been called a presumption of obviousness or a prima facie case of obviousness. In re Henze, 181 F.2d 196, 37 CCPA 1009, 85 USPQ 261 (CCPA 1950); In re Hass, 141 F.2d 122, 127, 130, 31 CCPA 895, 60 USPQ 544, 548, 552 (CCPA 1944). The burden then shifts to the applicant, who then can present arguments and/or data to show that what appears to be obvious, is not in fact that, when the invention is looked at as a whole. In re Papesch, 315 F.2d 381, 50 CCPA 1084, 137 USPQ 43 (CCPA 1963). The cases of Hass and Henze established the rule that, unless an applicant showed that the prior art compound lacked the property or advantage asserted for the claimed compound, the presumption of un-patentability was not overcome. Exactly what facts constituted a prima facie case varied from case to ease, but it was not the law that, where an applicant asserted that an invention possessed properties not known to be possessed by the prior art, no prima facie case was established unless the reference also showed the novel activity. There are cases, cited in the dissent, in which a prima facie case was not established based on lack of structural similarity. See In re Grabiak, 769 F.2d 729, 732, 226 USPQ 870, 872 (Fed.Cir.1985); In re Taborsky, 502 F.2d 775, 780-81, 183 USPQ 50, 55 (CCPA 1974). Some of the cited cases also contained language suggesting that the fact that the claimed and the prior art compounds possessed the same activity were added factors in the establishment of the prima facie case. E.g., In re Zeidler, 682 F.2d 961, 966, 215 USPQ 490, 494 (CCPA 1982); In re Grunwell, 609 F.2d 486, 491, 203 USPQ 1055, 1058 (CCPA 1979); In re Payne, 606 F.2d 303, 314, 203 USPQ 245, 255 (CCPA 1979); In re Swan Wood, 582 F.2d 638, 641, 199 USPQ 137, 139 (CCPA 1978); In re Lamberti, 545 F.2d 747, 751, 192 USPQ 278, 281 (CCPA 1976); In re Susi, 440 F.2d 442, 445, 58 CCPA 1074, 169 USPQ 423, 426 (CCPA 1971). Those cases did not say, however, as the dissent asserts, that, in the absence of the similarity of activities, there would have been no prima facie case. For example, the dissent quotes a statement in Grabiak that “[w]hen chemical compounds have ‘very close’ structural similarities and similar utilities, without more a prima facie case may be made.” 769 F.2d at 731, 226 USPQ at 871. That case does not state, as implied by the dissent, that without the similarity of utilities, there would not have been a prima facie case. A conclusion based on one set of facts does not necessarily rule out a similar conclusion with slightly different facts. One case cited by the dissent as “rejecting the PTO’s interpretation of Henze as establishing a ‘legal presumption’ of obviousness” was In re Mills, 281 F.2d 218, 47 CCPA 1185, 126 USPQ 513 (CCPA 1960). All that case decided, however, was that a one-carbon member of a homologous series is too far from the prior art disclosure of 8 to 12 members to justify the presumption. Id. at 223-24, 126 USPQ at 517-18. We will not review all the cases cited in the dissent, but Stemniski is an important case, for it overruled Henze and In re Riden, 318 F.2d 761, 50 CCPA 1411, 138 USPQ 112 (CCPA 1963) (a case similar to Henze), “to the extent that [they] are inconsistent with the views expressed herein.” 444 F.2d at 587, 170 USPQ at 348. The views that were expressed therein were that: [w]here the prior art reference neither discloses nor suggests a utility for certain described compounds, why should it be said that a reference makes obvious to one of ordinary skill in the art an isomer, homolog or analog or related structure, when that mythical, but intensely practical, person knows of no “practical” reason to make the reference compounds, much less any structurally related compounds? Id. at 586, 170 USPQ at 347. Thus, Stem-niski, rather than destroying the established practice of rejecting closely-related compounds as prima facie obvious, qualified it by holding that a presumption is not created when the reference compound is so lacking in any utility that there is no motivation to make close relatives. Albrecht followed this line of thinking when it held that the prior art compound so irritated the skin that it could not be regarded as useful and therefore did not create a motivation to make related compounds. 514 F.2d at 1392, 1395-96, 185 USPQ at 587, 590. Properties, therefore, are relevant to the creation of a prima facie case in the sense of affecting the motivation of a researcher to make compounds closely related to or suggested by a prior art compound, but it is not required, as stated in the dissent, that the prior art disclose or suggest the properties newly-discovered by an applicant in order for there to be a prima facie case of obviousness.- The dissent cites the seminal case of Papesch, suggesting that it rejected the principle that we now “adopt,” thereby implying that we are weakening Papesch. We are doing nothing of the sort. Papesch indeed stated that a compound and all of its properties are inseparable and must be considered in the determination of obviousness. We heartily agree and intend not to retreat from Papesch one inch. Papesch, however, did not deal with the requirements for establishing a prima facie case, but whether the examiner had to consider the properties of an invention at all, when there was a presumption of obviousness. 315 F.2d at 391, 137 USPQ at 51. The reference disclosed a lower homolog of the claimed compounds, so it was clear that impliedly a prima facie case existed; the question was whether, under those circumstances, the biological data were admissible at all. The court ruled that they were, id. at 391, 137 USPQ at 51, and we agree with that result. The dissent quotes the brief passage at the end of the Papesch opinion to the effect that the prior art must “at least to a degree” disclose the applicant’s desired property, id. at 392, 137 USPQ at 52, but this brief mention was not central to the decision in that case and did not refer to the requirements of a prima facie ease. Papesch is irrelevant to the question of the requirements for a prima facie case, which is the question we have here. The dissent refers to a number of cases, including In re Lunsford, 357 F.2d 380, 53 CCPA 986, 148 USPQ 716 (CCPA 1966), stating that the court had rejected the Patent Office’s position of “structures only.” That case must be understood in the context of the refusal of the examiner to consider any showing of improved properties, not in the context of a discussion whether a prima facie case was created. The compounds were conceded to be sufficiently close to the prior art that, without a showing of a significant difference in properties, they would have been obvious. Id. at 381, 148 USPQ at 717. The dissent asserts that the Shetty case “diverg[ed] from the weight of [the court’s] precedent” in holding that a prima facie case was made based on similarities of structure. The court, in that opinion, accepted the prima facie case and concluded ' that “appellant ha[d] offered no evidence of unobviousness, as by showing an actual difference in properties.” 566 F.2d at 86, 195 USPQ at 756 (citing Hock). The opinion does not suggest that the court was diverging from the weight of precedent. The dissent mentions positions advanced by the Commissioner, including citing the In re Mod, 408 F.2d 1055, 56 CCPA 1041, 161 USPQ 281 (CCPA 1969) and In re de Montmollin, 344 F.2d 976, 52 CCPA 1287, 145 USPQ 416 (CCPA 1965) decisions. We do not, however, in today’s decision necessarily adopt any positions of the Commissioner other than those stated in our opinion and note that neither Mod nor de Mont-mollin dealt with the requirements of a prima facie case. They concerned the question whether the existence of a new property for claimed compounds in addition to a property common to both the claimed and related prior art compounds rendered the claimed compounds unobvious. We are not faced with that question today. Other cases, e.g., In re Gyurik, 596 F.2d 1012, 1018, 201 USPQ 552, 557-58 (CCPA 1979) (“[n]o common-properties presumption rises from the mere occurrence of a claimed compound at an intermediate point in a conventional reaction yielding a specifically named prior art compound”), have qualified the original rule of the Hass-Henze cases, but it is clear that they have not enunciated a rule that, in order to make a prima facie case of obviousness, the examiner must show that the prior art suggests a new property discovered by applicant. In not accepting that principle today, as urged in the dissent, we are therefore not retreating from the recent trend of case law development or changing the law. Another example of the lack of direct pertinence of a case quoted in the dissent is May, which the dissent cites as an example of the consistent line of decisions to the effect that “both structure and properties must be suggested in the prior art before a prima facie case of obviousness was deemed made.” This case does not state that both structure and properties “must” be suggested. The claimed and prior art compositions were both disclosed as having analgesic activity; it was conceded that a prima facie case was made out, but the court concluded that applicants had rebutted the presumed expectation that structurally similar compounds have similar properties with a showing of an actual unexpected difference of properties between the claimed compound and the prior art. 574 F.2d at 1095, 197 USPQ at 611. The applicant in that case thus made a showing that Dillon did not make in this case. Properties must be considered in the overall evaluation of obviousness, and the lack of any disclosure of useful properties for a prior art compound may indicate a lack of motivation to make related compounds, thereby precluding a prima facie case, but it is not correct that similarity of structure and a suggestion of the activity of an applicant’s compounds in the prior art are necessary before a prima facie case is established. Conclusion We affirm the Board's decision rejecting claims 2-14, 16-22, and 24-37. AFFIRMED. ARCHER, Circuit Judge, with whom MARKEY and MICHEL, Circuit Judges, join, joining-in-part. I join the majority opinion except to note that the comments on In re Durden, 763 F.2d 1406, 226 USPQ 359 (Fed.Cir.1985), are unnecessary to the decision of this case. The method claims were not rejected by the Board on the basis of that case and, in fact, were not separately considered by the Board. Until a rejection of a method claim based on Durden is appealed to this court and the issue fully briefed, it is premature to consider the scope and effect of Durden. Accordingly, I do not join this part of the majority opinion. . A panel of this court heard this appeal and reversed the Board on December 29, 1989. 892 F.2d 1554, 13 USPQ2d 1337. The PTO petitioned for rehearing and suggested rehearing in banc on February 12, 1990. Rehearing in banc was ordered on May 21, 1990, and the judgment which was entered on December 29, 1989, was vacated, the accompanying opinion being withdrawn. . Tri-orthoesters have three —OR groups bonded to a central carbon atom, and the fourth carbon bond is to hydrogen or a hydrocarbon group ( — R); they are represented as C(R)(OR)g. Tetra-orthoesters have four —OR groups bonded to a central carbon atom, and are represented as C(OR)4; see Dillon's claims, supra. . The earlier, now-withdrawn Dillon opinion, this opinion, and the dissent cite and rely on cases involving claims to chemical compounds, whereas this case involves compositions. The reason for this reliance is that, in this case, the principal difference between the claimed and prior art compositions is the difference between chemical compounds, viz,, tri-orthoesters and tetra-orthoesters. Cases dealing with chemical compounds are therefore directly analogous here and, in view of the history of this case and its in banc status, we will make much comment on these cases in this opinion. We do not, however, intend to imply that in all cases involving claimed compositions, structural obviousness between involved chemical compounds necessarily makes the claimed compositions pri-ma facie obvious. . The dissent misinterprets this comment as indicating that claims to new compounds and compositions must contain a limitation to a specific use, and states that past cases have rejected this proposition. Our comment only points out that the composition claims on appeal are not structurally or physically distinguishable from the prior art compositions by virtue of the recitation of their newly-discovered use. . See M.A. Litman, Obvious Process Rejections Under 35 USC 103, 71 JPTOS 775 (1989); H.C. Wegner, Much Ado About Durden, 71 JPTOS 785 (1989).
NEWMAN, Circuit Judge, with whom COWEN, Senior Circuit Judge, and MAYER, Circuit Judge, join, dissenting. The court today resolves certain disparities in the extensive body of precedent on the question of obviousness of new chemical compounds and compositions. However, these disparities are resolved in a way that is contrary to the weight and direction of this precedent, as embodied in over three decades of decision. The court departs from its considered development of the law governing patentability of new chemical compounds and compositions, and reinstates a rule of “structural obviousness”. In so ruling the court not only rejects the weight of precedent, but also errs in the application of 35 U.S.C. §§ 101, 102, and 103. The majority’s holding that prima facie obviousness of new chemical compounds and compositions is determined based only on structural similarity to prior art compounds and compositions having a known use is reminiscent of the “Hass-Henze Doctrine” of earlier days. This doctrine was discarded thirty years ago, and although it resurfaced on occasion, its original sweep was superseded by many years of judicial analysis. Review of this analysis shows the courts’ evolving understanding of the characteristics of chemical inventions, particularly the inseparability of chemical properties and chemical structure, and the legal consequences of this scientific fact. Judicial decisions over the past three decades established the general rule that the determination of prima facie obviousness of new chemical compounds and compositions and their uses can not be based on chemical structure alone, but must also include consideration of all their properties, including those discovered by the applicant. This rule had important procedural and substantive consequences during patent examination, for it determined the kind of evidence and proof that was required of a patent applicant. The ruling of this in banc court changes what must be proved in order to patent a new chemical compound or composition, and thus changes what is patentable. The body of precedent establishing the burdens of modern patent examination was developed in judicial decisions applying the 1952 Patent Act. As I shall discuss in greater detail, when patent examination showed that the prior art suggested the inventor’s new chemical structure and the inventor’s newly discovered property and use, a prima facie case of obviousness of the new chemical compound or composition and its use was deemed made. The inventor could, of course, argue that the differences from the prior art were such that a prima facie case was not made. And the inventor could rebut the prima facie case of obviousness, by showing some unexpected difference in structure or properties and use, not apparent from the teachings of the prior art. Such rebuttal was generally presented in the form of comparative experimental data, whereby the inventor demonstrated that the properties of his or her new chemical compound or composition achieved some unobvious or unexpected result or advantage, as compared with the actual properties of the prior art structure. This rebuttal often required the inventor to go beyond the general teachings in the prior art, and prove that the prior art compound did not, in fact, possess the specific property and advantage of the new compound or composition. Such proofs were invariably required when the prior art suggested the general property and use discovered by the applicant. Many dozens of decisions of the CCPA and this court illustrate this procedure, and the variety of factual circumstances in which it has been invoked. In accordance with the court’s in banc holding, a new chemical compound or composition is not patentable even when the prior art does not suggest that the new chemical compound or composition would have the applicant’s newly discovered property and use, unless the applicant makes the same showing that is required when the prior art does suggest the applicant’s new property and use. The applicant is thus required to show “unexpected” properties and results, whether or not the prior art provides an expectation or suggestion of the properties and results disclosed in the patent application. And unless the applicant proves that the prior art structure does not actually possess the same unobvious property that the applicant discovered for the new structure, the court holds today that the new chemical compound or composition is not patentable. This is an incorrect application of the patent statute, and a rejection of the wisdom of precedent. Therefore, respectfully, I dissent. I THE LAW A The In Banc Issue Diane M. Dillon appeals the decision of the PTO Board of Patent Appeals and Interferences, which had rejected all of Dillon’s claims on the basis that “The claimed subject matter would have been prima fa-cie obvious from the combined teachings of the references.” The Commissioner, asking the court to choose between divergent decisions of the CCPA, stated the PTO position that prima facie obviousness should be based on chemical structure alone: [I]f the prior art suggests an inventor’s compound or composition per se, that compound or composition would be pri-ma facie obvious, regardless of the properties disclosed in the inventor’s application. Commissioner’s brief at 24. The majority of the in banc court adopts the Commissioner’s position, expressly rejecting the panel’s position that the properties and use discovered by the applicant must be considered in connection with determination of the prima facie case under section 103, thereby overruling all prior decisions that so held. I would hold that determination of whether a prima facie case of obviousness has been made requires consideration of the similarities and differences as to structure and properties and utility, between the applicant’s new compounds or compositions and those shown in the prior art. The Graham [v. John Deere Co., 383 U.S. 1, 86 S.Ct. 684, 15 L.Ed.2d 545, 148 USPQ 459 (1966) ] factors can not be ignored in determination of the prima facie case under 35 U.S.C. § 103. As illustrated in precedent, pertinent considerations in determination of whether a prima facie case is made include the closeness of the prior art subject matter to the field of the invention, the motivation or suggestion in the prior art to combine the reference teachings, the problem that the inventor was trying to solve, the nature of the inventor’s improvement as compared with the prior art, and a variety of other criteria as may arise in a particular case; all with respect to the invention as a whole, and decided from the viewpoint of a person of ordinary skill in the field of the invention. Of course not all these aspects will loom large in every case, but when present they must be considered. They are as pertinent to determination of the prima facie case as they are to the determination that is made after rebuttal evidence is adduced by the applicant. Structure alone, without consideration of the applicant's newly discovered properties, is an incomplete focus for consideration of these factors. B The Prima Facie Case The prima facie case, as used in patent examination, means not only that the evidence of the prior art reasonably allows the examiner’s conclusion of unpatentability, but also that the prior art compels such a conclusion as a matter of law, if the applicant produces no evidence to rebut it. Black’s Law Dictionary, 1071 (5th Ed.1979); In re Piasecki, 745 F.2d 1468, 1472, 223 USPQ 785, 788 (Fed.Cir.1984). See the discussion in In re Mills, 281 F.2d 218, 222 & n. 2, 47 CCPA 1185, 126 USPQ 513, 516 & n. 2 (CCPA 1960), of the “presumption of unpatentability” based on prior art, a judicial usage before the term “prima facie case” appeared in CCPA and board decisions. Patentability is determined, in the first instance, by examination of the patent application in the PTO. The prior art is searched by the patent examiner, who determines whether a prima facie case of unpatentability is made based on what was known in the prior art. Piasecki, supra. The prima facie rejection may be challenged by the applicant on grounds such as that the rejection is insufficiently supported, or incorrect, or based on illogical reasoning; or, if a prima facie case is made, evidence may be adduced in rebuttal. In re Heldt, 433 F.2d 808, 811, 58 CCPA 701, 167 USPQ 676, 678 (CCPA 1970). The prima facie case is not “oet in concrete”, and upon the submission of rebuttal evidence the determination of obviousness vel non is made on the entire record. In re Rinehart, 531 F.2d 1048, 1052, 189 USPQ 143, 147 (CCPA 1976). The initial determination by the patent examiner is critical to further proceedings, for the presence or absence of a prima facie case of-obviousness controls the need for the applicant to adduce rebuttal evidence of unobviousness. The procedure serves to clearly allocate the burdens of going forward and of persuasion as between the examiner and the applicant. In re Johnson, 747 F.2d 1456, 1460, 223 USPQ 1260, 1263 (Fed.Cir.1984). It determines what the applicant must prove, and the kind of evidence the applicant must provide. Thus it determines what is patentable under the statute. While many judicial decisions turn on the question of adequacy of the rebuttal evidence, the concern of the in banc court today is the issue of the prima facie case. For when, as here, no rebuttal evidence is presented, determination of the prima fa-cie case is decision of the question of pat-entability. As illustrated in Dillon’s case, the question of whether there is a prima facie case of obviousness controls whether Dillon is required to prove that her newly discovered property of particulate (soot) reduction during combustion is not actually possessed by the prior art composition, when the prior art composition was not known or suggested to have this property. Dillon did not so prove, and the Commissioner urges that since Dillon’s specification itself discloses that the prior art composition does possess this newly discovered property, the prima facie case based on structural similarity was not rebutted. Heretofore, the courts generally recognized a controlling distinction between the two principal types of factual situations that arise when a patent applicant’s new chemical compound or composition has a structure that is “similar” to chemical structures shown in the prior art: (1) those where the prior art suggests, at least in general terms, that the new chemical compound or composition will have the applicant’s newly discovered property and use; and (2) those where it does not. These factual situations have had different consequences with respect to whether a prima facie case of obviousness was made. The difference turned on whether or not the structure and properties and use of a new chemical compound or composition were suggested in the prior art. The distinction determined whether the applicant was required to come forward with rebuttal evidence, which often was in the form of new technological information not known to the prior art, in order to establish an “unexpected” difference between the properties discovered by the applicant and those actually possessed by the prior art structure. This distinction brought a consistent application of the law of 35 U.S.C. § 103 to the examination of chemical inventions, for it established the framework wherein the law was applied to the facts of each case. The court today rejects this distinction, holding in banc that it suffices to show prima facie obviousness whenever the pri- or art describes a similar chemical structure, provided only that the prior art gives some “reason or motivation” to make the claimed chemical structure, “regardless of the properties disclosed in the inventor’s application”, in the Commissioner’s words. This position is contrary to the weight and direction of precedent, as I shall illustrate, and is contrary to the statutory imperatives of Title 35. C Precedent It is critical to an effective patent system that there be consistent law, consistently applied, despite the great diversity of technologies that the patent system must serve. The law that is applied in determining whether a prima facie case of obviousness is made, as to new chemical compounds and compositions and their uses, has evolved from analysis of many different factual situations. The large number of decisions on this issue, of this court and the CCPA, produced a rich body of precedent. The following outline of precedent is chronological, and has its roots in cases decided before enactment of the 1952 Patent Act. For a while, during an earlier period of modern chemistry, “structural obviousness” alone was deemed to create a presumption of unpatentability. Leading decisions were In re Hass, 141 F.2d 122, 127, 130, 31 CCPA 895, 60 USPQ 544, 548, 552 (CCPA 1944) and In re Henze, 181 F.2d 196, 37 CCPA 1009, 85 USPQ 261 (CCPA 1950). In these decisions the CCPA held that there was a presumption of obviousness based solely on the close similarity of structure of chemical homologs, regardless of the new property and use that the applicant discovered. Thus a new compound, if a homolog of a known compound, was not patentable unless the applicant overcame this presumption by showing that there was in fact a significant and unexpected difference in the actual properties of the new compound as compared with the actual, albeit unknown to the prior art, properties of the known homolog: The burden is on the applicant to rebut that presumption by a showing that the claimed compound possesses unobvious or unexpected beneficial properties not actually possessed by the prior art homologue. Henze, 181 F.2d at 201, 85 USPQ at 265 (emphases in original). This difference in properties was required to be shown to exist, whether or not the prior art suggested the property and utility discovered by the inventor for the new compound, and whether or not there was any reason to expect the prior art compound to have that property or utility. The court held: It is immaterial that the prior art homologue may not be recognized or known to be useful for the same purposes or to possess the same properties as the claimed compound. Id. (emphasis in original). The courts soon expressed dissatisfaction with this rule. See the discussion, and cases cited, in In re Mills, 281 F.2d 218, 47 CCPA 1185, 126 USPQ 513 (CCPA 1960). In Mills the CCPA limited the Henze presumption to adjacent homologs, and rejected the PTO’s interpretation of Henze as establishing a “legal presumption” of obviousness. The court held that homology alone does not create an inference of unpa-tentability or shift the burden of persuasion, but is simply a fact “which must be considered with all other relevant facts before arriving at the conclusion of ‘obviousness’ specified in 35 U.S.C. § 103.” Id. 281 F.2d at 224, 126 USPQ at 518. Throughout the 1960’s, and thereafter, the CCPA stressed that properties as well as structure were material to the patenta-bility of new chemicals, and must be considered. The case of In re Papesch, 315 F.2d 381, 50 CCPA 1084, 137 USPQ 43 (CCPA 1963) is often cited for its statement that “a chemical compound and all of its properties are inseparable”. Id. at 391, 137 USPQ at 51. See Papesch for citation of a number of decisions of the CCPA and other courts after • Henze, illustrating judicial understanding that chemical structure is not severable from chemical (including biochemical) properties in patentability determinations; for it is the properties that determine the utility that is requisite to pat-entability. The Papesch court rejected the principle that this court now adopts, for in Papesch the court held that the prior art must disclose “at least to a degree” the applicant’s desired property and utility. The court said: The other factor of importance ... is that the prior art disclosure was not merely of a structurally similar compound but also, at least to a degree, of the same desired property relied on for the patentability of the new compound. Such an “other factor” must of course be considered because it bears on the obviousness of the compound, which is, realistically and legally, a composite of both structure and properties. Id. at 392, 137 USPQ at 52 (emphasis in original). The majority today disposes of this passage, long the bulwark of chemical practice, as “a brief mention”, and “irrelevant” to the prima facie case. This passage has been reinforced myriad times after its appearance in Papesch, and has been a foundation of the prima facie case in examination of chemical patent applications for obviousness in terms of section 103. Although the CCPA and the Patent Office at the time of Papesch did not generally use the terminology “prima facie case”, the CCPA’s holding that a compound is “realistically and legally, a composite of both structure and properties”, underlies the requirement that both structure and properties be considered. Papesch and its extensive progeny establish that the prior art disclosure should be “at least to a degree, of the same desired property”, id., even for a homolog. Absent such disclosure, the presumption of unpatentability did not arise. This requirement, that both structure and properties be considered, simply continued when the terminology of the prima facie case was adopted to describe a legally sufficient ease of obviousness under section 103. In In re De Lajarte, 337 F.2d 870, 52 CCPA 826, 143 USPQ 256 (CCPA 1964) the same principle was applied to a new composition. The CCPA held that similarity of chemical composition alone did not place on the applicant the obligation of proving that the prior art composition did not possess the applicant’s newly discovered property and utility: In the total absence of evidence in the record to indicate that the amber glass disclosed by Lyle would be expected to have desirable electrical insulating properties, we can find no justification for placing the burden on applicant to conduct experiments to determine the insulating properties of the colored glass disclosed by Lyle. Id. at 874, 143 USPQ at 259. As in the modern usage of the prima facie case, the court held that the prior art must suggest both similar structure and property before the burden shifted to the applicant to prove unexpected differences. De Lajarte’s claims were to a novel glass composition having insulating properties. The prior art (Lyle) reference showed a glass composition having what the examiner called “very slight differences” in structure, and the properties of amber color and durability. The court said: If one were making a colorless glass free of carbon and sulfur, there would be little reason for using the Lyle formula since it was primarily designed to enhance color stability. In the absence of any showing why it would be obvious to modify Lyle’s glass, a “103 rejection” must be reversed. Id. at 875, 143 USPQ at 259. In In re Ruschig, 343 F.2d 965, 52 CCPA 1238, 145 USPQ 274 (CCPA 1965) the court again observed that the invention “indeed, is a ‘conjunction of utility and product’, though claimed as new compounds found to have the desired biological effect”. (Emphasis in original.) The court criticized the PTO position that “the examiner and the board thought the compounds, looked upon as mere chemical formulae, would have been obvious”. Id. at 973, 145 USPQ at 281. The court stated: On the obviousness issue, the vague “basket” disclosure of possible uses in the French and Swedish patents and the equally vague disclosure of the Martin patent are unimportant. What is important is the fact that the utility discovered by the appellants is not disclosed in the prior art. Id. at 977, 145 USPQ at 285 (emphasis in original). That the utility discovered by the applicant must be at least suggested in the prior art, in order to establish prima facie unpa-tentability of new compounds and compositions that are structurally similar to known chemicals, is the common thread that ties most of the decisions of the CCPA and the Federal Circuit. I do not attempt to include all of the cases that illustrate this point. I do, however, include representative cases of divergent holding, and those that appear to be relied on by the majority. For example, the Commissioner cites In re de Montmollin, 344 F.2d 976, 52 CCPA 1287, 145 USPQ 416 (CCPA 1965) as supporting authority. In de Montmollin the claimed invention was a new compound, described by the applicant as useful for dyeing wool and cotton. The reference showed structurally similar compounds useful for dyeing wool. The court concluded that the additional ability of de Mont-mollin’s claimed compound to dye cotton was not “sufficient to render the subject matter as a whole unobvious”. Id. at 979, 145 USPQ at 417-18. This case simply illustrates determination of obviousness by comparing the structures and properties taught in the prior art with those disclosed by the applicant, and bringing judgment to bear on “the subject matter as a whole.” Id. It does not support the position that a prima facie case under section 103 is made on structural similarity, regardless of the applicant’s newly discovered property and use. The principle that both structure and properties must be considered in connection with the prima facie case was directly treated in In re Rosselet, 347 F.2d 847, 52 CCPA 1533, 146 USPQ 183 (CCPA 1965), where the court held that “gross similarity” of chemical structure and the same area of pharmacological activity constituted a prima facie case of obviousness: We agree with appellant’s admonitions against deciding questions of chemical obviousness on the basis of structure alone, whether by means of a “mechanistic overlay” or otherwise. However, we think appellants have failed to present adequate evidence to overcome a prima facie showing of obviousness by reason of the admitted “gross structural similarities” of the art compounds, coupled with the fact those compounds are shown to have utility in the same area of pharmacological activity. Id. at 850, 146 USPQ at 185 (emphases in original). Other decisions during this period illustrate varying judicial emphases, depending on the facts. When the compounds were quite closely related in chemical structure, as in the homologs and analogs of In re Riden, 318 F.2d 761, 50 CCPA 1411, 138 USPQ 112 (CCPA 1963), or the position isomers of In re Mehta, 347 F.2d 859, 52 CCPA 1615, 146 USPQ 284 (CCPA 1965), the court gave greater evidentiary weight to the structural similarities than when the structures were less directly comparable. However, the court regularly admonished that: A compound is not, however, merely a structural formula; its properties as part of the whole must be considered. Id. at 864, 146 USPQ at 287. In In re Lunsford, 357 F.2d 380, 53 CCPA 986, 148 USPQ 716 (CCPA 1966) the court listed eight recent decisions in which it had rejected the Patent Office’s position of “comparison of structures only”: Just how one finds the compounds “obvious” in the first instance, the examiner does not say, but apparently he envisions a comparison of structures only. That such an approach is not sanctioned by this court, although concededly the law was less well defined in June 1961, the date of the Examiner’s Answer, can be seen, e.g., in In re Krazinski, 347 F.2d 656 [52 CCPA 1447], 146 USPQ 25 [ (CCPA 1965) ]; In re Ruschig, 343 F.2d 965 [52 CCPA 1238], 145 USPQ 274 [(CCPA 1965)]; In re Ward, 329 F.2d 1021 [51 CCPA 1123], 141 USPQ 227 [(CCPA 1964)]; In re Lunsford, 327 F.2d 526 [51 CCPA 1000], 140 USPQ 425 [(CCPA 1964)]; In re Riden, Jr., 318 F.2d 761 [50 CCPA 1411], 138 USPQ 112 [ (CCPA 1963) ]; In re Papesch, 315 F.2d 381 [50 CCPA 1084], 137 USPQ 43 [ (CCPA 1963) ]; In re Petering, 301 F.2d 676 [49 CCPA 993], 133 USPQ 275 [(CCPA 1962)]; In re Lambooy, 300 F.2d 950 [49 CCPA 985], 133 USPQ 270 [(CCPA 1962)]. Id. at 382 n. 2, 148 USPQ at 718 n. 2 (emphasis in original). The court reiterated: [T]he discovered activities or properties are part of the things claimed, the compounds .... [W]e, like the Patent Office, are required by the clear wording of section 103 to regard it as a relevant portion of the invention “as a whole.” Id. at 384, 148 USPQ at 720 (emphasis in original). In a companion case, In re Lunsford, 357 F.2d 385, 53 CCPA 1011, 148 USPQ 721 (CCPA 1966), the court again stressed that determination of obviousness must be based on both structure and properties. The court quoted the Patent Office position, in the examiner’s words: The argument that the “subject matter as a whole” under 35 U.S.C. 103 includes the compound and its utility is considered to be without merit. Id. at 391, 148 USPQ at 725. The court once more firmly rejected that position: [I]t is reasonably clear that the examiner considered only the difference in structures between the claimed compounds and the prior art compounds. Appellant was entitled to have differences between the claimed invention, the subject