This appeal is from the decision of the United States Patent and Trademark Office (PTO) Board of Appeals (board) affirming the rejection of claims 1-19 and 21-26 in appellants' application serial No. 412,061, filed November 2, 1973, for “Sulfonation Process,” under 35 U.S.C. § 103 as obvious from the teachings of the prior art references. We affirm.
The Invention
Appellants disclose an improved process for sulfonating hydrocarbon gas oil feedstock with liquid sulfur trioxide (SO3) diluted in ethylene dichloride (EDC). The resulting petroleum sulfonates are allegedly useful for imparting micellar characteristics to mixtures of hydrocarbons and water. Secondary and tertiary oil recovery techniques employ emulsifiers like these sulfonates to increase the yield of “depleted” oil fields. Primary oil recovery techniques using pressure often leave large amounts of crude oil in natural formations. More crude oil can be economically recovered, however, by flooding these formations with micellar formations.
Sulfonates capable of forming a micellar petroleum dispersion must have a proper hydrophil-lipophil balance (HLB). The average equivalent weight1 of the sulfonate is said to be a major quality control parameter directly related to the HLB. The relative degree of monosulfonation versus polysulfonation is indicated by the equivalent weight. An increasing polysulfonation, represented by a lowering equivalent weight, is stated to be undesirable. A sulfonate equivalent weight less than about 350 is said to adversely influence the micellar properties of the petroleum sulfonate product. A suitable range is 350 to 525 and 375 to 470 is preferred.
Various parameters are alleged to control a monosulfonation reaction. Particular attention is paid to defining the hydrocarbon reactant. The feedstock must have an average molecular weight of broadly about 250 to about 700. The aliphatic to aromatic proton (A/AP) ratio2 should be between 5 and 50. In addition, the aromatic content is held generally between 30% and 100%.
Liquid S03, the other reactant, which reacts with the feedstock, must be diluted with EDC prior to a turbulent mixing in order to promote a more even sulfonation. The EDC concentration purportedly is critical. At less than 0.05 lb. SO3/O.35 lb. EDC, the reactant stream becomes a two-phase flow resulting in undesired product. On the upper end, ratios greater than 0.35 allegedly produce sulfonates with unacceptable emulsifying properties.
Some of the claims incorporate an additional temperature limitation.3 Sulfonate products are maintained within about 100° to about 250° F. after leaving the reaction zone. The specification states that these temperatures are measured in the area “immediately downstream of the reaction zone.”
The remaining process steps recited in the claims are conventional prior-art procedures for the neutralization and recovery of petroleum sulfonates.
The References
Marisicetal. 2,828,331 Mar. 25,1958
Blakeway et al. 3,346,505 Oct. 10,1967
Marisic relates to a sulfonation process for petroleum oils, more particularly, lubri*1143eating oils. One of the enunciated objects of the disclosed method is the avoidance of thermal buildups and associated undesirable side reactions, i. e., oxidation and polysulfonation.
Several factors are stated by Marisic to contribute to the formation of suitable sulfonates. Superior yields of high quality sulfonic acids are said to be obtained “by employing turbulent flow conditions within the liquid phase of sulfonatable material present in the reaction zone * * * and assuring a pressure drop of at least about 50 p.s.i.g. between the sulfonating agent [S03] and sulfonatable material * * *
In Marisic’s summary of sulfonation experiments, Table 1, high treat levels, i. e., weight per cent (wt. %) concentrations, of SO3 are said to be found in examples 1, 6, 8, and 9; respectively, 8.0 wt. %, 5.0 wt. %, 4.6 wt. % and 7.3 wt. %. Concentrations of EDC as an S03 diluent range from 0.37 lb. of S03 in Example 6 to 0.66 lb. of SO3 in Example 2, per lb. of EDC. As a further guide to SO3 concentrations, Marisic declares that in devising his process preliminary tests showed that a 15 wt. % SO3 treat produced severe oxidation and polysulfonation to the extent that no recoverable sulfonates were obtained.
Regarding the choice of a hydrocarbon reactant, Marisic relates the following prerequisites. “As long as the sulfonatable material may be caused to flow under turbulent conditions through a reaction zone while mixing with an injected stream of diluted sulfur trioxide-containing sulfonating agent or be brought from a quiescent state to turbulent flow conditions by such injection under the prescribed pressure drop or pressure differential,” petroleum sulfonates may be successfully obtained. Thus, sulfonating temperature, reactant ratios, and flow velocities are said to be dependent upon the initial reactants and the desired product determinable by one skilled in the art.
Blake way, the secondary reference, discloses a co-sulfonation process, for organics of differing volatilities. A less volatile hydrocarbon component is introduced into a reaction zone with vaporized SO3 diluted by an inert gas. A more volatile component is subsequently introduced with an additional amount of diluted S03 only after the first fraction has been partially sulfonated. As in Marisic, a turbulent mixing site is employed for introducing the hydrocarbons. But a two-stage, in-line reactor is needed instead of the single stage reactor in Mari-sic.
The Ossip Affidavit
An affidavit by Paul S. Ossip was submitted to the examiner under 37 CFR 1.132 after a first rejection. Ossip, an admittedly skilled organic chemist, sulfonated Wyoming heavy gas oils4 in a reactor with S03 diluted by N2. The pertinent process parameters were averred to have been as follows: a temperature of 104° ± 10°F., at atmospheric pressure, a 15 wt. % SO3 treat level, and a 50% by volume dilution of feedstock with selected solvents.
Following neutralization, a three-phase extraction was performed. The middle phase, containing the desired product but neither the unreacted oil nor unwanted polysulfonates, was analyzed. The table below presents the analytical results:
Percent SOg
Converted to
Example No. Solvent for Gas Oil Sulfonate
1 Ethylene dichloride 56
2 Chlorobenzene 62
3 O-dichlorobenzene 63
4 Trichloroethylene 46
5 1,1, % 2-Tetra-
chloroethane 55
6 Nitrobenzene 54
7 2-Nitropropane 44
8 1,2-Dichloropropane 56
9 Cis-1,2-dichloroethylene 58
Ossip declared that the product of significant, polysulfonation side reactions would partition into the lower phase, thereby low*1144ering the SO3 per cent conversion in thfe middle phase. The test was held to show that EDC is comparable to other solvents in its promotion of polysulfonation.
The Board
Characterizing appellants' method as an efficient sulfonation process for producing petroleum emulsifiers, the board held that
* * * it would have been prima facie obvious to the chemist of ordinary skill to apply the sulfonation conditions of Mari-sic et al to hydrocarbon oils of the type encompassed by the claims with the expectation that a useful sulfonated emulsifying agent would be produced.
Both appellants and Marisic were said to encounter the problem of unwanted polysulfonation formation.
Appellants achieve their purpose by carefully controlling the sulfonation reaction conditions, specifically the ratio of S03 to its specific diluent ethylene dichloride (EDC), the ratio of SOs to the hydrocarbon feed stock, the reaction temperature and to some extent the degree of agitation of the reaction process.
These reaction conditions were found by the board to be “essentially the same” as those disclosed in Marisic for achieving the same result, petroleum monosulfonates.
The materiality of the claimed feedstock limitation was stated to be immaterial to the sulfonation process.
The nature of the feed, while it may affect the emulsifying properties of the product, would not be expected to materially alter or otherwise affect the course of the sulfonation reaction or reaction mechanism involved therein. One of ordinary skill in the sulfonation art would not have any logical reason to believe that the sulfonation process described in the art would not be generally applicable to all hydrocarbon oils, including those specifically claimed herein. Moreover, as indicated by the Examiner, Blakeway et al tend to support the view that hydrocarbon oils within the scope of those claimed would be expected to be subject to general sulfonation reaction conditions.
Particularly noted was the lack of any evidence to distinguish between the product of appellants’ process and conventional emulsifying agents.
Finally, the Ossip affidavit was held to be irrelevant to determining the obviousness of the present invention. Attention was specifically drawn to the absence of any indication that the sulfonation of Wyoming oil was performed in accordance with the claims.
In affirming the examiner’s rejection, the board described appellants’ process parameters as an optimization of a prior art process which achieves expected results, i. e., monosulfonation without significant side reactions. None of the claimed limitations were held to have any significant effect on the sulfonation of hydrocarbons.
OPINION
At the outset, we note that the claimed invention is an improved process. The disputed obviousness of this method must be determined by comparing, as a whole, steps effecting the present method with those known in the prior art at the time the invention was made, as viewed by one of ordinary skill in the art. Resolution of this contested issue begins with deciding whether the feedstock selection step can be properly considered as a process limitation bearing on obviousness.
The solicitor advocates that this court should disregard feedstock criteria when determining the establishment of prima facie obviousness because it is a non-essential feature of the recited process. More particularly, we are asked to treat this limitation as in In re Kanter, 55 CCPA 1395, 399 F.2d 249, 158 USPQ 331 (1968), where a specific material was acted upon by a known process in an expected manner. We decline to do so.
Polysulfonation is a known problem in the hydrocarbon sulfonation art. Reacting feedstocks may be uncontrollably sulfonated with more than one SO3 substituent per molecule. These actively occurring side *1145processes or reactions are known to create tarry, totally unacceptable products if left unchecked. Marisic, for example, coordinated various steps, i. e., turbulence, pressure drop, etc., to alleviate this problem. Certainly the prior art recognizes polysulfonation as an unwanted yet essential process feature accompanying monosulfonation processes employing SO3.
Appellants disclose a novel means to effectively control these side processes. Feedstock composition is carefully controlled to attain a specific aliphatic-aromatic balance. By doing so, hydrocarbons reacting under prescribed conditions alleviate the side process problem. Therefore, we hold that the feedstock selection step is a relevant chemical process step to be considered in determining nonobviousness under § 103.
The nature of the present feedstock is decidedly different from Kanter where the claimed process involved the application of a silicon coating to a steel article. There, a change in the steel crystalline structure to a stable, body-centered cubic orientation, i. e., an “alpha-delta” alloy, purportedly improved the adherence of the coating to the substrate. But as we said in Kanter, “The process itself [, not the product thereof,] must satisfy the statutory conditions for patentability.” Thus, one may look at a starting material to the extent that it affects the process. In Kanter, the different crystalline structure did not actively affect and materially alter the manner in which silicon coated the steel. In contrast to this appeal, no adverse side processes in Kanter were effected by material selection.
Even though the feedstock limitation was improperly ignored, the board correctly held that the claimed process is prima facie obvious. Blakeway is not necessary for any such showing. Marisic broadly teaches that petroleum and aromatic fractions are sulfonatable materials when turbulently mixed with a 4-10 wt. % liquid SO3 treat diluted with EDC. It is irrelevant that the instant feedstocks are a mixture of aromatic compounds. In the claimed process, specific feedstocks are carved out from known sulfonatable petroleum and aromatic fractions and are treated with S03 at levels which touch the upper treat limit in Mari-sic. In addition, the diluent concentrations for SO3 in EDC are overlapped by those of the examples in Marisic. It is the close similarity of all the related process steps as a whole which establishes obviousness here.
Appellants argue that the acknowledged failure of Marisic at 15 wt. % reveals a fundamental difference in appellants’ process, feedstock selection does appear to permit operability in the claimed process where the prior art specifically admits failure. However, the claims are not limited to 15 wt. %, but are much broader in scope, i. e., from 0.10 to about 0.20 wt. %, a range which extends into operable prior art values. Even though claims 11 and 14-26 recite an additional temperature limitation, these temperatures are relatively close to the disclosed operating temperatures in Marisic. Therefore, arguments concerning the non-recognition of the role feedstocks play in effecting other known parameters of sulfonation processes are irrelevant to the formulation of a prima facie case. In re Malagari, 499 F.2d 1297, 182 USPQ 549 (CCPA 1974).
The Ossip affidavit does not rebut the prima facie obviousness derived from Mari-sic. We agree with appellants that the Ossip sulfonation was in accordance with the claimed process. Ossip reveals that polysulfonation is controlled at a 15 wt. % SO3 treat, an unexpected result which respect to Marisic. While relevant, this alone is not sufficient for rebuttal. The SO3 treat range in the appealed claims is expressed as a range of treat levels which extends into operable prior art values. Therefore, the sole SO3 treat level of 15 wt. % in Ossip is not commensurate in scope with the claims. Unexpected differences must be shown in the lower claimed treat levels where the foundation for obviousness resides.
*1146The alleged relevance of Ossip in demonstrating the equivalence of EDC as a diluent is based upon a misconstruction of Mari-sic. The prior art recommendation for discarding liquid-liquid EDC sulfonation involved the use of “wetted wall columns,” not the turbulent zone reactors used by Marisic and appellants. As shown in Table II (columns 9 and 10), EDC was used as a S08 diluent in an operable, turbulent zone sulfonation process. Therefore its use is not unexpected.
Without sufficient relevant evidence to rebut the prima facie obviousness of the present invention as claimed, the rejection of claims 1-19 and 21-26 is affirmed
AFFIRMED.