DETAILED ACTION
Notice of Pre-AIA or AIA Status
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Claim Rejections - 35 USC § 103
In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis (i.e., changing from AIA to pre-AIA ) for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status.
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
The factual inquiries for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows:
1. Determining the scope and contents of the prior art.
2. Ascertaining the differences between the prior art and the claims at issue.
3. Resolving the level of ordinary skill in the pertinent art.
4. Considering objective evidence present in the application indicating obviousness or nonobviousness.
Claims 15-28 are rejected under 35 U.S.C. 103 as being unpatentable over Daikin (EP 3238820 A1).
Applicants’ claimed invention is directed to a process for treating, in a reactor containing a catalytic bed, a solid catalyst, said process comprising the steps of: a) implementing, in said reactor, a gas-phase catalytic reaction at a catalytic bed temperature T1 in the presence of a hydrogen halide or giving rise to the formation of a hydrogen halide, and b) causing an inert gas to flow through the catalytic bed at a catalytic bed temperature T2 that is lower than T1, the temperature T2 being greater than 30°C.
Daikin teaches a process for treating a solid catalyst (chromium oxide) in a reactor.
Step a) Daikin teaches a gas phase catalytic reaction (synthesis of CF3CF=CH2) at a catalytic bed temperature T1 of 350C in the presence of a hydrogen fluoride (anhydrous hydrogen fluoride).
Step b) Daikin teaches a purge step using an inert gas (nitrogen) flowing through the catalytic bed.
Temperature T2: Daikin specially discloses a heating step where the temperature is changed to 355 C during the nitrogen purge. Furthermore, Daikin teaches a general range of this step where T2≥T1-100. See Example and claims.
Comparison to claimed limitations:
T2>300C: Daikin disclosed temperature of 355 0C (and the range T1-100, which at T1 =350 equals 2500C) clearly satisfies the requirement that T2 be greater than 300C.
T2<T1: while Daikin specific example (3550C) shows T2 slightly higher than T1, Daikin broader teaching ( T2≥T1-100) overlaps with the claimed range where T2 is lower than T1. For instance, if T1 is 350C, Daikin’s range includes 250≤ T2<3500C.
Claims 15, 18, 19, 23, 24 and 25 are deemed unpatentable under 35 USC 103, Daikin renders the claimed gas phase treatment process obvious through its broader, overlapping temperature range. Furthermore, implementing a lower purge temperature within Daikin’s teachings is technically straightforward for a person of ordinary skill in the art, prior to the effective filing date of the claimed invention, as it maintains necessary safety threshold to prevent acid condensation.
Regarding claim16, discloses introducing nitrogen gas into a reactor maintained at a high temperature (T2=3550C). While Daikin does not explicitly state the storage temperature of the nitrogen before it enters the reactor, it is inherent or a mater of routine design to suppl industrial gases from ambient-temperature cylinders or through standard pre-heating systems. See Example and claims.
A person ordinary skill in the art, prior to the effective filing date of claimed invention, prior to the effective filing date of the claimed invention would find it obvious to introduce the gas at a temperature between ambient and the bed temperature T2 to avoid unnecessary energy expenditure for superheating the gas beyond the reactor’s operating setpoint. Furthermore, the selection of an inlet gas temperature within the range is a predictable optimization of the heat exchange between the cold inert gas and the hot catalytic bed.
Regarding claim 17, while Daikin specifies the temperature of the catalytic bed during the purge (T2=3550C) it is silent on the temperature of the nitrogen gas at the exact moment of introduction into the reactor. However, it is a standard and well-known industrial practice to supply inert gas (like nitrogen) from high pressure cylinders or cryogenic tanks, which are typically stored and delivered at ambient temperature. See example and claims.
A person ordinary skill in the art, prior to the effective filing date of claimed invention, prior to the effective filing date of the claimed would find it obvious to introduce the gas at the ambient temperature to simplify the system design and avoid the cost and complexity of a pre-heating stage, relying instead on the heat of the catalytic bed (T2) to warm the gas upon contact. The choice to omit preheating of a purge gas is a routine design choice with predictable results.
Regarding claim 20, while Daikin specific example mentions a heating step to 355 (T2), it is well-established in chemical engineering that a reactor will naturally lose heat to its surroundings unless actively and precisely compensated by heating jacket. A person ordinary skill in the art would recognize that as a hot catalyst bed (T1=350C) is purged with a cooler inert gas (such as ambient temperature nitrogen (discussed in claim 17) , the temperature T2 will inherently decrease over time due the convective cooling.
Furthermore, Daikin’s broader teaching (T2≥T1-100) provides a range that encompasses a downward temperature ramp . choosing to allow the temperature to drop during the purge step rather than maintaining a strictly isothermal state is routine operational choice to save energy once the bulk of the corrosive halides has been removed. Therefore, the limitation of T2 decreasing during step b) is a predictable application of thermodynamics and does not lend patentable weight to the claim.
Regarding claim 21, while Daikin does not explicitly state the numerical cooling rate of the catalytic bed during the purge step, the limitation of a cooling rate less than 10C.min represent a routine optimization standard industrial cooling protocol. A person ordinary skill in the art, would recognize that large scale reactors, such as the one disclosed in Daikin containing a solid catalytic bed , possess significant thermal inertia and insulation that naturally result in gradual temperature changes when transitioning between setpoint. Furthermore, maintaining a slow cooling rate is a conventional engineering practice used to prevent thermal shock to the catalyst and reactor materials, ensuring structural integrity. In the absence of evidence demonstrating that this specific numerical threshold produces a surprising or non-obvious technical effect, the selection of a cooling rate of less than 10C/min is considered a predictable application of thermodynamics and routine process control.
Regarding claim 22, this claim is unpatentable over Daikin because the selection of a specific gas flow rate relative to catalyst volume is a matter of routine process optimization. Daikin discloses a specific nitrogen flow rate (200 ml/min) over a fixed amount of catalyst (20g), which inherently establishes a flow to volume ratio. A person ordinary skill in the art would recognize that the flow rate must be scaled based on the catalyst bed volume to ensure sufficient mass transfer for the complete removal of corrosive hydrogen halides while minimizing gas consumption. Adjusting this ratio to be greater than 0.1ml/min per ml of a catalyst represents a predictable application of standard chemical engineering scaling laws, where the flow rate is tuned to the reactor’s specific geometry and the desired purge efficiency. In the absence of evidence showing that this specific lower limit of 0.1 ml/min per ml of a catalyst produces a surprising technical effect or solves a problem not already addressed by the purging process in Daikin, the claimed ratio is considered an obvious choice among a range of functional parameters.
Regarding claim 26, while Daikin focuses on the chemical synthesis and purging step, the final step of unloading the catalyst is an inherent and necessary part of any industrial or laboratory catalytic process once the catalyst has reached the end of its life or the reactor require maintenance. A person ordinary skill in the art would find it entirely obvious to remove the solid catalyst from the reactor after the treatment process of step a) and b) is complete, especially since the purge step is specifically designed to make the catalyst and reactor environment safe for handling by removing corrosive hydrogen halides. The act of unloading is a conventional post processing step that involves no specialized chemical transformation and yields the predictable result of emptying the reaction vessel for its next intended use.
Regarding claim 27, Daikin discloses changing the reaction temperature to a target purge temperature (355 0C) and introducing nitrogen gas. A person of ordinary skill in the art would recognize that in any industrial transition from a reaction state to a treatment sate, the temperature must first be adjusted (cooled or heated) to reach the desire setpoint before or during the introduction of the treatment gas. Performing these actions in a specific sequence cooling the bed to a stable T2 before initiating the full inert gas flow is a predictable process control choice intended to ensure the catalytic bed is at a uniform, safe temperature to prevent the condensation of hydrogen halides upon contact with the purge gas. In the absence of evidence showing that this specific order of operations produces an unexpected technical advantage over simultaneous cooling and flowing, the claimed sequence is considered a matter of conventional engineering design.
Regarding claim 28, the subject matter of claim 28 is considered obvious because the limitation that the temperature T2 decreases during the inert gas flow is an inherent and predictable result of standard reactor operation. Daikin discloses a transition from a reaction temperature T1 (350 0C) to a treatment temperature T2 (355 0c) followed by an inert gas purge. A person ordinary skill in the art, prior to the effective filing date of the claimed invention would recognize that when a heated catalytic bed is subjected to a continuous flow of a cooler inert gas (such as the ambient temperature nitrogen discussed in previous claims), the bed will naturally lose heat through convective cooling. Furthermore, once the initial high temperature thermal treatment is complete, allowing the temperature to decrease during the remainder of the purge is a routine energy saving measure that does not change the fundamental nature of the gas phase treatment. In the absence of evidence that a specific cooling profile during step b) provides a surprising technical advantage, the decreasing temperature T2 is viewed as a predictable application of thermodynamics.
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/JAFAR F PARSA/ Primary Examiner, Art Unit 1692
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