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 .
Applicant's election with traverse of Group I, claims 18-32 in the reply filed on July 27, 2026, is acknowledged. The traversal is on the ground(s) that “US 2011/0319662, discloses passing chlorine and carbon monoxide feed streams through catalyst tubes filled with beds of activated carbon in a reactor comprising a bundle of catalyst tubes at around 400°C to give a product gas mixture from which liquid phosgene is separated off, but it does not disclose dividing that product gas into a same-composition recycle stream and recombining it with fresh feed in the specific ratio recited in claim 18. This is not found persuasive because splitting the product gas into a same-composition recycle stream and recombining it with fresh feed in the specific ratio are considered obvious variation for the reasons which will be provided in the following office action .
The requirement is still deemed proper and is therefore made FINAL.
Claim Rejections - 35 USC § 112
Claim 31 is rejected under 35 U.S.C.112(b) because the boundaries of the claim are indefinite. The text relies on third-party standard DIN 66135-2 and DIN 66134 to define the diameters of the micropores and mesopores.
Under USPTO guidelines, these codes represent proprietary standards and trademarks that can be altered or updated by the German Institute for standardization at any time without patent Office oversight. Because the testing methodologies within these standards can shift over time, a competitor cannot determine with legal certainty whether their measurement techniques infringe the claim, making the structural boundaries of the catalyst indefinite.
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 18-22 and 24-27 are rejected under 35 U.S.C. 103 as being unpatentable over Olbert et al (US 20110319662 A1).
Applicants’ claimed invention is directed to a continuous process for preparing phosgene, comprising (i) providing a gas stream G1 comprising carbon monoxide (CO) and chlorine (Cl2);(ii) passing the gas stream G1 into a reaction zone Z1, bringing the gas stream G1 into contact with a catalyst C1 comprised in said reaction zone Z1, obtaining a gas stream GP comprising phosgene and one or more of carbon monoxide and chlorine, and removing the gas stream GP from said reaction zone Z1;(iii) dividing the gas stream GP, obtaining at least two gas streams comprising a gas stream G2 and a gas stream GR, G2 and GR having the same chemical composition as GP, wherein the ratio of the mass flow f(GR) of the gas stream GR relative to the mass flow f(G2) of the gas stream G2, f(GR):f(G2), is in the range of from 0.1:1 to 20:1;wherein during standard operation mode of the continuous process, providing the gas stream G1 according to (i) comprises preparing G1 as a mixture comprising at least two gas streams, said at least two streams comprising the gas stream GR and j gas streams GO(k) with k=1, ... j, wherein the j gas streams GO(k) in total comprise carbon monoxide (CO) and chlorine (C12) and wherein j is in the range of from 1 to 3.
Regarding claims 18 and 20, Olbert teaches a continuous process for preparing phosgene by reacting a chlorine feed stream and a carbon monoxide feed stream in a multi-tube bundle reactor packed with activated carbon [0011] and [0039].
Olbert explicitly teaches that a major portion of the unreacted gas stream remaining after liquid phosgene condensation is isolated and recirculated back to the reactor entrance as a recycle stream [0023] and [0040]. Paragraph [0024] explicitly specifies the volumetric parameters of this loop: “The substream which is recirculated as recycle stream to a point upstream of the phosgene reactor can amount to preferably from 40 to 95% by weight, preferably from 75 to 90% by weight, of the gas stream which remains from the product gas mixture after the liquid phosgene has been separated off.
The differences between the claimed invention and prior art, Olbert calculates and defines its recycle loop split based strictly on the weight percentage (40% to 95% by weight) of the remaining uncondensed waste off-gas stream isolated downstream of the product condensers. See [0024], [0026] and [0040].
The claimed invention defines this boundary conditions as a direct mass flow ratio of the primary split streams themselves, f(GR):f(G2), maintaining it inline in the range of 0.1:1 to 20:1 (claim 18) and narrowing it to 0.2:1 to 10:1 (claim 20).
It would have been obvious to a person having ordinary skill in the art, prior to the effective filing date of the claimed invention to modify the continuous phosgene synthesis process taught by Olbert to calculate, monitor, and maintain the inline mass flow ratio of the split streams, f(GR):f(G2), within the broad range of 0.1:1 to 20:1 (as recited in claim 18) or the narrowed range of 0.2:1 to 10:1 (as recited in claim 20).
Olbert explicitly requires routing a massive portion up to 95% by weight—of the uncondensed reactor exit gas back to the front-end mixing zone [0024]. A PHOSITA tasked with running a continuous, steady-state chemical manufacturing plant must maintain a strict global and local mass balance. Calculating the raw mass flow rate of a diverted fluid stream (f(GR)) relative to the forward-facing fluid stream (f(G2)) at any given node in a pipeline loop is a routine, baseline engineering calculation.
Because Olbert already explicitly teaches recycling up to 95% of the remaining gas stream[0024], the resulting operational mass flow ratios across the plant’s piping network will inherently fall within or mathematically overlap with the claimed windows of 0.1:1 to 20:1 and 0.2:1 to 10:1. The selection of these specific inline flow ratios represents nothing more than the routine optimization of known operational parameters to maximize production capacity and balance system pressures. As such, the subject matter of claims 18 and 20 lacks an inventive step and is unpatentable under 35 U.S.C. 103 over Olbert. The rejection can be overcome by demonstrating a critical functional divergence is control response loops that yields an unexpected technical effect.
Regarding claims 19, 21 and 22, Olbert teaches a continuous process for preparing phosgene by reacting a chlorine feed stream and a carbon monoxide feed stream in a multi-tube bundle reactor [0011].
Paragraph 0039 explicitly describes the introduction of fresh chemical streams: ”The schematic depiction in Fig. 1 shows a phosgene reactor R into which a chlorine feed stream, reference numeral 2, and a carbon monoxide feed stream, reference numeral 3, are fed as feed stream 1 after combining and mixing in a static mixer M.”
Paragraph 0040 details how the recycle gas intersects with these feeds: “The recycle stream 8 is recycled to a point upstream of the reactor R via a driving jet nozzle T which is, for example, driven by means of the admission pressure of the carbon monoxide feed stream 3.”
Differences between the claimed invention and the prior art, Claims 19 and 21 (variable J): Olbert shows a concrete physical layout with exactly two fresh feed lines (CO and Cl2) and one recycle loop line. It does not frame its input parameters using the abstract mathematical variables “j gas streams where j is 1 or 2” (claim 19) or “j=2 fresh gas streams” (claim 21).
Claim 22 (Mixing Sequence): Olbert teaches that fresh CO drives the jet nozzle to draw in the recycle stream first (creating CO + recycle blend), and then the fresh chlorine stream is introduced downstream into that blend inside a static mixer [0039] and [0040].
Claim 22 requires the exact combination sequence: first combining the fresh CO stream (G0(1)) with the fresh Cl2 stream (G0(2)) to make a combined fresh feed and then admixing the recycle stream (GR) into that combined fresh feed.
It would have been obvious to a person having ordinary skill in the art, prior to the effective filing date of the claimed invention to modify the phosgene synthesis process taught by Olbert to restrict the number of fresh feed streams to j=1 or j=2 (claim 19) to utilize exactly two fresh feed streams G0(1) and G0(2) in addition to the recycle stream GR (claim 21), and to combine the fresh CO and chlorine streams before admixing the recycle stream (claim 22).
Arranging a chemical reactor with a specific number of fresh feed lines is a routine engineering layout choice. Olbert’s own schematic configuration explicitly utilizes exactly two fresh feed lines, a carbon monoxide line (3) and chlorine line (2) acting in tandem with a single recycling loop (8) (paragraph 0039, 0040). Expressing this physical three-line layout using the indexed mathematical terms “j=2 gas streams G0(1) and G0(2)” represents a mere linguistic distinction that lacks patentable weight over Olbert’s explicit structural disclosure.
Furthermore, altering the sequence in which these three separate gas lines (G0(1), G0(2), and GTR) are merged into a common reactor inlet manifold is a routine optimization within the capability of an ordinary plant design engineer. Olbert explicitly teaches that all three streams are combined to form a single blended feed stream 1 prior to entering the reactor bed [0039]. Whether an engineer chooses to mix the fresh reactants G0(1) and G0(2) first and then introduce the recycled gas (GR) as recited in claim 22, or mix the CO and recycle gas first as shown in Olbert, represents a simple choice between known mechanical piping alternative. A PHOSITA would expect either sequence to yield an identical, uniform multi-component gas mixture (G1) at the reactor inlet, with no expectation of an unexpected technical effect. Consequently, the subject matter of claims 19, 21, and 22 lacks an inventive step and is unpatentable under U.S.C. 103 over Olbert.
Regarding claim 24, Olbert recites a stoichiometric excess of CO in the range from 1 to 10% [0008] rather than a chlorine to CO mole ratio expressed in the format 0.6:1 to 0.999:1. If CO is 1% excess there are 1.01 moles of CO for every 1.00 mole of Cl2. Ratio =1.00/1.01=0.990:1
If CO is in a 10% excess, there are 1.10 moles of CO for every 1.00 mole of Cl2.
Ratio =1.00/1.10=0.909:1.
Olbert entire operational spectrum (0.901:1 to 0.990:1) sits squarely inside the claimed range 0.6:1 to 0.999:1.
Regarding claim 27, Olbert uses a standard multi-tube bundle reactor packed with activated carbon [0011].
Regarding claim 26, Olbert teaches a mixing sequence where the fresh carbon monoxide feed stream (3) is blended with the recycle stream (8) first, and then the fresh chlorine feed stream (2) is combined with that mixture inside a static mixer (M) [0039] and [0040]. Differences between the claimed invention and the Olbert reference: claim 26 requires the exact reverse sequence, the fresh chlorine feed stream (G0(2)) is admixed with the recycle stream (GR) first, and then the fresh carbon monoxide stream (G0(1)) is combined with that mixture downstream.
It would therefore have been obvious to a person having ordinary skill in the art, prior to the effective filing date of the claimed invention to modify Olbert’s phosgene synthesis process by reversing the gas mixing sequence to first admix the fresh chlorine feed with the recycle stream before introducing the carbon monoxide downstream as recited in claim 26. This alteration in the physical sequence of gas lines entering the common manifold represents a routine mechanical design choice and optimization with a reasonable expectation of achieving the requisite uniform gas mixture, lacking patentable weight under 35 U.S.C. 103.
Regarding claim 25, Olbert explicitly teaches a continuous phosgene manufacturing process combining fresh carbon monoxide and recycle streams via a driving jet nozzle before blending with fresh chlorine in a downstream mixer. The sole difference is that claim 25 expresses this mixing sequence using mathematical variables rather than Olbert’s physical stream labels. This configuration would have been obvious to a person having ordinary skill in the art as it merely adopts Olbert’s preferred sequence of introducing recycled process gas [0039]-[0040] and Figure 1.
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.
Claims 23, 28-32 are rejected under 35 U.S.C. 103 as being unpatentable over Olbert et al (US 20110319662 A1 as applied to claims 18-22, and 24-27 above, and further in view of Gautam et al (US 20170001943 A1).
Olbert teaches a continuous process for preparing phosgene where a fresh carbon monoxide (3) and fresh chlorine stream (2) are combined and mixed with a recycle gas stream (8) inside a static mixer (M) or via a driving jet nozzle (T) [0039],[0040] and Fig. 1.
The difference between Olbert and the claimed invention is that Olbert explicitly limits its front-end system to static mixers or passive driving jet nozzle to prevent mechanical component failures. Claim 23 expand the technical mixing option to a discrete Markush group reciting an ejector, a static mixer or a dynamic mixer.
On the other hand, Gautam teaches gas-phase phosgene producing utilizing modern, specialized multi-stage mixing hardware matrices to systematically blend carbon monoxide and chlorine reactants uniformly prior to catalyst entry [0113].
It would have been obvious to a person having ordinary skill in the art, prior to the effective filing date of the claimed invention to utilize an ejector, a static mixer, or a dynamic mixer within the process layout of Olbert in view of Gautam. Olbert already explicitly teaches combining the fresh reactants and recycle loops using standard fluidic mixing hardware, specifically a jet nozzle and a static mixer [0039]-[0040].
Furthermore, substituting passive mixing nozzle for conventional dynamic mixing manifolds represents a routine, predictable selection of standard chemical processing hardware alternatives. A PHOSITA tasked with optimizing fluid homogeneity at a reactor inlet would readily evaluate known active or passive mixing choices to ensure a uniform composition, with a reasonable expectation of predictable success.
Regarding claim 28, Olbert teaches reacting chlorine and carbon monoxide inside catalyst tubes packed with activated carbon beds at elevated temperature around 4000C [0003],[0011]. It evaluates localized runway parameters retroactively via an external, downstream chlorine breakthrough analyzer at the tube outlet [0021] and [0046].
Gautam explicitly teaches that controlling exothermic heat of reaction during phosgene synthesis is crucial to suppress the formation of unwanted side-products. Gautam demonstrate managing local heat spikes inside reactor configurations where temperature profiles are actively tracked to optimized yield and limit secondary decomposition [0034].
While Olbert tracks thermal overruns via downstream chlorine analysis, the claim monitors internal bed temperature using an inline multipoint thermocouple to maintain a maximum of 450C. Modifying Olbert with Gautam’s active internal temperature profiling would be obvious to a PHOSITA to prevent localized thermal runaway.
Regarding claims 30 and 31, Olbert uses generic activated carbon [0011], whereas Gautam outlines specialized pore sizes [0071]. Claim 31 specifies a mesopore volume of a least 0.45 ml/g via dual isotherm NLDFT. Selecting such carbon framework to optimize mass transport is an obvious application of Gautam’s teachings to Olbert’s catalyst bed.
Regarding claim 32, Olbert teaches a main reactor, and an after-reactor [0031] and Gautam describes a multi-stage tube reactor setup [0113]. Routing stream G2 into a second reaction zone Z2 maps directly to these combined multi-stage conversion strategies.
Regarding claim 29, a person ordinary skill in the art, prior to the effective filing date of the claimed invention to modify the phosgene synthesis process of Olbert in view of the gas processing methods of Gautam to route the auxiliary gas stream GR through a return loop via an ejector configuration as recited in claim 29. Olbert explicitly mandate in paragraph 0040 that the gas-phase recirculation loop must rely on a driving jet nozzle “T” (figure 1)powered by the admission pressure of an incoming feed stream to continuously draw the recycle gas back into the system. Because a pressure -driven jet nozzle operating on venturi fluid dynamics to entrain a suction stream into a high-pressure motive stream is the literal structural equivalent of a gas-phase ejector, substituting or identifying Olbert’s generic driving jet nozzle as a standard industrial ejector represents a routine application of known fluidic components to achieve their predictable, intended purpose, rendering the structural step of claim 29 obvious under 35 U.S.C. 103.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to JAFAR F PARSA whose telephone number is (571)272-0643. The examiner can normally be reached M-F 10:00 AM-6:30PM.
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/JAFAR F PARSA/Primary Examiner, Art Unit 1692
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