T 2305/11 – Mind The Gap

This is an examination appeal.

Claim 1 of the main request before the Board read (in English translation):

Extraction process for the recovery of soluble substances from plant or animal organic raw materials under high pressure, in which raw-material-specific oils and fats have a maximum solubility pressure, of 1000 bar at most, wherein

• supercritical CO₂ is used as a solvent;
• one or more high-pressure vessels are filled with the organic material, sealed and then submitted to a pressure of more than 800 bar, subsequently
• the supercritical CO₂ is passed at least once through the filled high-pressure vessel in an extraction stage, without admixing any additional entrainer to the supercritical CO₂ and subsequently
• the laden supercritical CO₂ is completely or partly supplied to a separating stage in which natural substances or substance mixtures are separated or separated of each other while decreasing the pressure,

characterized in that

the pressure in the extraction stage exceeds the maximum solubility pressure of the raw-material-specific oil or fat in the supercritical gas by at least 10%, the respective raw-material-specific oil or fat acting as entrainer.

The Board found the invention to be insufficiently disclosed:

*** Translation of the German original ***

Essential feature

[2.1] The claimed extraction process comprises the essential and characterising feature that the the pressure in the extraction stage exceeds the so-called “maximum solubility pressure of 1000 bar at most” of the raw-material-specific oil or fat in the supercritical gas (CO₂) by at least 10%. According to the present application, said “maximum solubility pressure of 1000 bar at most” is to be understood as the pressure at which, at a given temperature, the solubility of the raw-material-specific oils or fats reaches a maximum value in the supercritical CO₂, in a pressure range of up to 1000 bar […].

Thus, in order to be able to carry out the claimed process, it is necessary to know this “maximum solubility pressure of 1000 bar at most”, or to be able to determine it. Otherwise, as the pressure in the extraction stage of the process according to the application has to be at least 10% higher than said “maximum solubility pressure”, it would not be clear at which pressure the extraction step is to be carried out.

Information gaps

[2.2] The application does not make any concrete statement on how to determine the “maximum solubility pressure of 1000 bar at most”. However, the Board accepts, in favour of the [applicant], that the skilled person knows appropriate methods. For instance, D5 (figure 35) discloses the measurement of the pressure dependence of solubility by means of phase equilibrium devices.

However, as will be discussed in what follows, the Board considers the fact that the application does not disclose that in many cases no “maximum solubility pressure of 1000 bar at most” is found and how one has to proceed in those cases to constitute a decisive information gap.

Assessment of the state of knowledge

[2.3.1] Figure 2 of D1 shows the dependence of the solubility of triglycerides in supercritical CO₂. There is no discernable maximum solubility for pressures up to 1000 bar and above. This has not been contested during the oral proceedings (OPs).

[2.3.2] D5 discloses details regarding the phase behaviour of soy oil in CO₂ at different temperatures in a range of pressures between 100 and 600 bar, and in the supercritical region until 1000 bar and above. For temperatures above about 60°C the maximum solubility already exceeds 1000 bar (see figure 37).

The solubility maxima of the curves in figure 40 of D5 concern the solubility of Jojoba oil in compressed CO₂ and lie below 1000 bar for the supercritical phase domains and temperatures of between 20 and 60°C […]. However, D5 warns that an extrapolation of the results obtained for soy oil is only possible for comparable oils from the oleic acid – linoleic acid group […]. Thus the Board is of the opinion that the existence of individual solubility maxima below 1000 bar for certain oils such as Jojoba oil cannot support the enablement of the claimed process for all raw-material-specific oils or fats.

What matters […] is that studies of the solubility behaviour of trigycerides during the extraction of the vegetable oil from the vegetable raw material in CO₂ have shown that there is no solubility maximum in the region of up to 1000 bar between 40°C and 80°C. The [applicant] has not contested this fact.

[2.3.3] Finally, the [applicant] itself has admitted […] during the OPs that there is no solubility maximum in the region of up to 1000 bar for some oils that are to be extracted.

[2.3.4] In view of this evidence, the Board considers the statement in paragraph [0005] of the description, according to which

“the boundary of 1000 bar disclosed in WO-A-2006/05 537 and EP 1 424 385 B1 … [is] identical with the physically determined region where the solubility maximum of raw-material-specific natural oils is found in supercritical CO₂”

to be a mere assertion that is not supported by the facts. The documents D6, D7, and D8 filed by the [applicant] do not support this alleged factual situation either because none of these documents discloses a solubility maximum in the region of up to 1000 bar. Moreover, D8 concerns the extraction of xanthohumol from hop and D7 the decaffeination of tea; there is no extraction of vegetable oil or fat in these cases, contrary to the present application. D6 was disclosed on January 22, 2009, and does not belong to the state of the art for this reason alone.

[2.3.5] The [applicant] has not submitted that these were only isolated cases which fell outside the performance of the process according to the invention because there was no solubility maximum, and that the skilled person could determine these isolated cases without undue experimental effort. The application does not explain for which oils and fats one would not expect to find a solubility maximum in the region of up to 1000 bar when the extraction is performed with supercritical CO₂.

Other passages of the disclosure

[2.4] The application can also contain references allowing the skilled person to carry out the invention; in such a case the invention would be sufficiently disclosed.

During the OPs the [applicant] asserted that the examples of the application […] concerning the extraction of sweet paprika, spicy paprika and tomato powder had been carried out after such a solubility maximum had been determined, but it was unable to provide plausible indications regarding the pressure values obtained; at least there are no such indications in the application. Thus it is impossible to check whether the examples are covered by the wording of claim 1.

[2.5] To sum up, the [applicant] was unable to respond to the objection of the Board as to how the invention was to be carried out when there was no solubility maximum in the region of up to 1000 bar, and in particular which pressure was to be used in the extraction stage. The description does not provide the skilled person with any useful guidance. [The applicant] has not shown how said information gaps and the lack of guidance can be filled or overcome with common technical knowledge, respectively.

Conclusion

[2.6] As a consequence, the claimed invention is not disclosed in a manner sufficiently clear and complete for it to be carried out by a person skilled in the art. This deficiency concerns the claims of both the main and the auxiliary requests, which do not differ in regard of the critical feature.

Thus the application does not comply with the provisions of A 83. […]

The appeal is dismissed.

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