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 .
Continued Examination Under 37 CFR 1.114
A request for continued examination under 37 CFR 1.114, including the fee set forth in 37 CFR 1.17(e), was filed in this application after final rejection. Since this application is eligible for continued examination under 37 CFR 1.114, and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114. Applicant's submission filed on 8/25/2025 has been entered.
Claim Status
Claim 1 was amended and claims 9 and 14 were canceled in the response filed 10/28/2025. Claims 1, 2, 5-8, 11-13, and 15-18 are currently pending and under examination.
Claim Rejections - 35 USC § 112(b)
The following is a quotation of 35 U.S.C. 112(b):
(b) CONCLUSION.—The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the inventor or a joint inventor regards as the invention.
The following is a quotation of 35 U.S.C. 112 (pre-AIA ), second paragraph:
The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the applicant regards as his invention.
Claims 12 and 18 are rejected under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA ), second paragraph, as being indefinite for failing to particularly point out and distinctly claim the subject matter which the inventor or a joint inventor (or for applications subject to pre-AIA 35 U.S.C. 112, the applicant), regards as the invention.
Claim 12 recites that the pyrolysis reaction is conducted under a pressure of 0.2 – 1 MPa in line 5. This limitation lacks antecedent basis to claim 1, which recites a pressure range of 0.2 – 0.4 MPa.
Claim 18 depends from a canceled claim (claim 9), and is therefore 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.
This application currently names joint inventors. In considering patentability of the claims the examiner presumes that the subject matter of the various claims was commonly owned as of the effective filing date of the claimed invention(s) absent any evidence to the contrary. Applicant is advised of the obligation under 37 CFR 1.56 to point out the inventor and effective filing dates of each claim that was not commonly owned as of the effective filing date of the later invention in order for the examiner to consider the applicability of 35 U.S.C. 102(b)(2)(C) for any potential 35 U.S.C. 102(a)(2) prior art against the later invention.
See p. 3-11 of the OA dated 5/27/2025 for the rejection of record.
Claim(s) 1, 2, 5-8, 11-13, and 15-18 is/are rejected under 35 U.S.C. 103 as being unpatentable over Rosenthal (US 3919279, published on 11/11/1975, of record in the IDS filed on 2/14/2022), Fujimora (CN105837471A, published on 8/10/2016, of record in the IDS filed on 2/14/2022), and Satoyuki (CN103772240A, published on 5/7/2014, of record in the IDS filed on 2/14/2022). Machine generated English language translations of Fujimori and Satoyuki are also of record (see PTO-892 dated 1/28/2025).
Applicant Claims
Applicant claims a preparation method for diphenylmethane diisocyanate, comprising: in the presence of a catalyst, subjecting diphenylmethane dicarbamate to a pyrolysis reaction in an inert solvent having a lower boiling point than diphenylmethane diisocyanate to obtain diphenylmethane diisocyanate;
Wherein a mass ratio of the catalyst to diphenylmethane dicarbamate is 1:(15-20);
Wherein the pyrolysis reaction is conducted at a temperature of 140-280°C under a pressure of 0.2-0.4 MPa, and
Wherein the diphenylmethane dicarbamate comprises any one of or a combination of at least two methyl diphenylmethane dicarbamate, ethyl diphenylmethane dicarbamate, propyl diphenylmethane dicarbamate, and butyl diphenylmethane dicarbamate.
Determining the Scope and Content of the Prior Art (MPEP §2141.01)
Rosenthal discloses the catalytic production of isocyanates from esters of carbamic acids (urethanes) by decomposing (pyrolyzing) the ester in the presence of a heavy metal or inorganic or organic compound of the heavy metal or mixtures or combinations thereof at elevated temperatures while said ester is dissolved in a suitable inert solvent to produce the isocyanate and alcohol and wherein the heavy metal catalyst may be as finely divided metal or a mixture of metals. See abstract.
Rosenthal teaches subjecting carbamates of formula R(NHCOOR’)x, including dicarbamates when x is 2, to a pyrolysis reaction in the presence of a heavy metal or heavy metal compound catalyst while said ester is dissolved in an inert solvent to produce the isocyanate, including diisocyanates when x is 2, and alcohol, wherein the inert solvent is (a) a solvent for the ester, (b) liquid and stable at said decomposition temperature, and (c) non-reaction with said isocyanate compound produced in said thermal decomposition reaction and is a compound or mixture of compounds selected from the group consisting of aliphatic, cycloaliphatic or aromatic hydrocarbons, substituted hydrocarbons, oxygenated compounds selected from the group consisting of ethers, ketones, and esters, and the sulfur analogues of said oxygenated compounds and separately recovering the isocyanate and alcohol. See claim 1.
Rosenthal teaches that the carbamate of formula R(NHCOOR’)x encompasses the claimed diphenylmethane dicarbamates when x is and R is a divalent aralkyl diphenylmethyl group. See col. 2, lines 5-27 and col. 2, line-col. 3, line 3. This compound would predictably produce a diphenylmethane diisocyanate of formula R(NCO)2, wherein R is diphenylmethyl, when subjected to the conditions of Rosenthal.
Regarding the catalyst, Rosenthal teaches that the catalyst encompasses heavy metals in their elemental form (elementary substance), including copper (Group IB/11) and nickel (Group VIIIB/10) and combinations thereof (claims 2, 5, and 15). See col. 6, lines 32-53 and Example V in col. 9-10. Rosenthal also teaches that the catalyst can be in a powder form, see “iron powder” in example V in col. 10, which would include copper powder (claim 16).
Regarding the solvent, Rosenthal teaches that the solvent encompasses both those with higher and lower boiling points than the isocyanate product. Rosenthal teaches that since the alcohol produced from the reaction usually has a lower boiling than the isocyanate, the separation of the alcohol from the isocyanate can be efficiently carried out by employing a solvent having a lower boiling point solvent than isocyanate. See col. 4, lines 18-36. Suitable solvents include ortho-xylene, para-xylene, and chlorobenzenes (claims 7 and 13). See col. 5, line 60-col. 6, line 10.
The process of Rosenthal can be carried out at temperatures ranging from 175 to 300C and for a time of between 1 to 20 hours. See col. 4, lines 1-13. Both of these ranges overlap with those of claims 1, 8, 12, and 17. Also see MPEP 2144.05. The pressure of the process is preferably run at atmospheric pressure (0.1 MPa) when a higher boiling solvent is used or it can be run at superatmospheric pressure (>0.1 MPa) when a lower boiling solvent is used. Therefore, the pressure range for the lower boiling point solvent encompasses the claimed range in claims 1, 12, and 18. Also see MPEP 2144.05.
Rosenthal teaches that the concentration of the carbamate reactant in the inert solvent should not exceed 70-80 weight percent based on the total weight of the solution. See col. 5, lines 1-5. Rosenthal also teaches that the carbamate should be soluble from at least 3 to 5 weight percent at reaction temperatures. See col. 4, lines 54-68. Therefore, taking 80wt% as the upper limit of the concentration of carbamate in the solvent and 3wt% as the lower limit of the concentration of carbamate in the solvent, and assuming the total weight percent is based on the solvent and carbamate (100 wt%) such that the lower limit of the concentration of solvent is 20 wt% and the higher limit of the concentration of the solvent is 97wt%, provides the following range of mass ratios of carbamate:solvent of 80:20 to 3:97, or 1:(0.25-32). This range encompasses the range of claim 6. Also see MPEP 2144.05.
Regarding the mass ratio of the catalyst to diphenylmethane dicarbamate of claim 1, Rosenthal teaches that the metal of the catalyst is present in the solution at reaction conditions in the range of less than 1 ppm to up to 10,000ppm. See col. 7, lines 10-25. 1 ppm corresponds to a mass percent of 0.0001% and 10,000 ppm corresponds to a mass percent of 1%. Therefore, the mass ratio of catalyst:solvent ranges from 0.0001:99.9999 to 1:99, or 1:(999999-99), or (1x10-6 – 0.1):1. The mass ratio of carbamate:solvent was calculated above to be 1:(0.25-32), or (4-0.03125):1. Therefore the mass ratio of solvent:catalyst:carbamate is approximately 1 : (1x10-6 – 0.1) : (0.03125-4) and the mass ratio of catalyst to : carbamate is approx. (1x10-6 – 0.1) : (0.03125-4), or 1:(40,000,000 – 0.3125). This approximate range encompasses that of claim 1. Further, the examples using elementary metals as the catalyst in examples V and VI employ from 0.01g to 2g of catalyst : 10 g carbamate, which corresponds to a mass ratio of (0.01-2):10, or 1:(1000-5), which also overlaps with the range in claim 1. See MPEP 2144.05. Rosenthal also teaches that the concentration of the catalyst is not particularly critical to the success of the reaction as long as a catalytic quantity is employed. See col. 7, lines 10-25.
Regarding the diphenylmethane dicarbamates of claim 1, though Rosenthal does not explicitly the use of one of the claimed dicarbamates, Rosenthal teaches that methyl and ethyl esters of carbamic acid are preferred because they are readily available. See col. 3, lines 51-58.
Fujimora teaches a two-stage pyrolysis device for preparation of polymethylene polyphenyl polyisocyanate by liquid phase pressurization thermal decomposition method and a pyrolysis method. A pyrolysis system includes a preliminary pyrolysis system and a depth pyrolysis system. The pyrolysis method includes the steps of: firstly, conducting preliminary pyrolysis of methyl polymethylene polyphenol polycarbamate through the preliminary pyrolysis system to realize a polymethylene polyphenyl polyisocyanate (the polymeric diphenylmethane diisocyanate yield of more than 85%, then conducting pyrolysis by the depth pyrolysis system to decompose a pyrolysis intermediate thoroughly to generate isocyanate, thus achieving an isocyanate yield of more than 99%. See abstract and claims.
Fujimora teaches that the process includes the use of an inert low boiling point solvent with a boiling point lower than polymethylene polyphenyl polyisocyanate, the solvent including toluene, xylenes, and chlorobenzenes (claim 7). See claim 8 and lines 171-174 of the translation of Fujimora. Fujimora teaches that the by-product alcohol can be easily removed from the polyisocyanate product and catalyst by using a lower boiling point solvent. See claims and examples.
Fujimora teaches that the pyrolysis process further comprises a catalyst, including elemental copper, iron, and nickel (claims 2 and 5). See lines 186-190 and claim 10.
The methyl polymethylene polyphenol polycarbamate of Fujimora encompasses the claimed reactant diphenylmethane diisocyanate which can be present as a polymer, as evidenced by example 17 on p .11-12 of the specification as filed.
Fujimora teaches that the ratio of carbamate:solvent is in the range of 1:(1-30) (claim 6); that the reaction temperature is 150-350C, that the residence time is 0.5-10 h, and that the pressure is 0.5 MPa to 4.5 MPa (claims 1, 8, and 12). Fujimora also teaches that the amount of metal catalyst is 0.01 to 20% of the total amount (mass) of the raw materials to be pyrolyzed. See claims 5-10. This corresponds to a mass ratio of catalyst:carbamate of (0.01-20): (99.99-80), or 1:(9999-0.25), which encompasses the range of claim 1.
Regarding the diphenylmethane dicarbamates of claim 1, though Fujimora does not explicitly the use of one of the claimed dicarbamates, Fujimora explicitly teaches the use of the methyl ester of polyphenylmethane polycarbamate in the examples.
Satoyuki discloses a method for preparation of methylene diphenyl diisocyanate (MDI) by decomposition of methylene diphenyl dicarbamate (MDC). Zinc oxide is used as a catalyst, the use amount of the catalyst is 0.01-5% of the mass of an inert solvent, the reaction temperature is 150-300DEG C, the use amount of the inert solvent is 5-100 times of the mass of the methylene diphenyl dicarbamate (MDC), the preparation method of the zinc oxide catalyst is as follows: first, mixing and dipping active carbon and an zinc salt solution, then drying, roasting to remove the activated carbon to prepare the zinc oxide catalyst. High yield of a methylene diphenyl diisocyanate (MDI) product can be obtained by the method, the reaction temperature is low, and the solvent consumption is less. See abstract and claims.
Satoyuki MDI stands for “4,4-diphenylmethane diisocyanate” (claim 11) and that MDC stands for “diphenylmethane dicarbamate”. See lines 14-22 of the translation. Therefore, Satoyuki teaches subjecting MDC to a pyrolysis reaction in an inert solvent in the presence of a zinc oxide catalyst to produce MDI. See lines 36-57 and 69-70 of the translation and claims 1 and 3. Satoyuki also teaches that MDI is a commercially valuable product and is widely used in aerospace, construction, and may other fields. See lines 20-26 of the translation.
Ascertainment of the Difference Between Scope of the Prior Art and the Claims (MPEP §2141.02-03)
Rosenthal teaches a process which renders obvious all of the claimed limitations, but does not explicitly teach an example wherein a diphenylmethane dicarbamate is employed in the reaction to produce a diphenylmethane diisocyanate.
Fujimora teaches a similar process to that of Rosenthal, which teaches that polymeric MDI (polyphenylmethane polyisocyanate) is known to be prepared by pyrolyzing the corresponding dicarbamate in the presence of the same catalysts as Rosenthal and in the presence of an inert solvent having a boiling point lower than the polyisocyanate. Fujimora, teaches that the polyisocyanate can be reproducibly produced in high yields (95%) using the process. Fujimora does not explicitly teach that the reaction can be applied to the claimed diphenylmethane dicarbamates.
Satoyuki is an analogous process to that of Rosenthal and Fujimora wherein diphenylmethane diisocyanate is pyrolyzed to form the corresponding diphenylmethane diisocyanate in the presence of an inert solvent and a zinc oxide catalyst. Satoyuki also teaches that the diphenylmethane dicarbamates products of the instant invention are industrially valuable.
Finding of Prima Facie Obviousness Rationale and Motivation (MPEP §2142-2143)
It would have been prima facie obvious to one of ordinary skill in the art to combine the teachings of Rosenthal, Fujimora, and Satoyuki with a reasonable expectation of success before the effective filing date of the claimed invention. A person of ordinary skill would have been motivated to use the process of Rosenthal to produce diphenylmethane dicarbamate from dimethylmethane diisocyanate because the genus of carbamates of Rosenthal encompasses that claimed, indicating that there would be a reasonable expectation to success of applying the reaction to the claimed dicarbamate. Additionally, Fujimora, which teaches substantially the same reaction as Rosenthal, explicitly teaches that polymeric polyphenylmethane polyisocyanates can be obtained in excellent yield using the combination of a metal catalyst and inert solvent with a boiling point lower than that of the polyisocyanate. Both Rosenthal and Fujimora also discuss that using a solvent with a lower boiling point than the isocyanate product is a known and effective strategy to separate lower boiling by-products from the isocyanate produces easily and efficiently. Therefore, the combination of Rosenthal and Fujimora provide a reasonable expectation of success that if diphenylmethane dicarbamates were employed in the reaction, then the corresponding diphenylmethane diisocyanates would be obtained. Satoyuki is cited to teach that this is a known and predictable transformation in the presence of similar conditions to those of Rosenthal and Fujimora. Satoyuki also teaches the industrial importance of diphenylmethane diioscyanates and provides extra motivation as to why the skilled artisan would desire to modify the process of Rosenthal and Fujimora to arrive at that claimed. Therefore, the combination of Rosenthal, Fujimora, and Satoyuki renders the instantly claimed process prima facie obvious.
Response to Arguments on p. 5-7 of the response filed 8/25/2025
The Applicant argues that none of Rosenthal, Fujimora, nor Satoyuki, teach carrying out the pyrolysis reaction within the claimed range of 0.2 to 0.4 MPa. As set forth in the OA dated 5/27/2025 and acknowledged by the Applicant in the penultimate paragraph on p. 6 of the response, Rosenthal teaches that the pressure of the process is preferably run at atmospheric pressure (0.1 MPa) when a higher boiling solvent is used or it can be run at superatmospheric pressure (>0.1 MPa) when a lower boiling solvent is used and Fujimura teaches a pressure range of 0.5 MPa to 4.5 MPa. This argument has been fully considered but is not persuasive. It is noted that the lower end of the claimed range (0.2 MPa) is very close to the preferred range in Rosenthal (0.1 MPa) and that the upper end of the claimed range (0.4 MPa) is very close to the lower limit in Fujimura (0.5 MPa). The values at both ends of the claimed range only differ from known ranges by 0.1 MPa. This is such a small difference such that both sets of reactions (the claimed reaction and that of the prior art) are presumed to operate in substantially the same manner to produce substantially similar predictable results. Also see MPEP 2144.05. Further, it is noted that the teaching of Rosenthal and Fujimura as a whole would indicate to the skilled artisan that any pressure within the range of 0.1 MPa to 4.5 MPa would be suitable to predictably carry out the pyrolysis reaction.
The Applicant further argues that though Fujimora and Rosenthal also teach ranges which encompass the claimed mass ratio of the catalyst to diphenylmethane dicarbamate, that the skilled artisan would not arrive at the claimed ratio based on their teachings (in addition to Satoyuki). This argument has been fully considered but is not persuasive. As argued in the preceding OA, in general Rosenthal teaches that if the catalyst is soluble in the reaction mixture, that a significantly lower concentration of said catalyst can be used. In contrast, the examples which employ heterogeneous catalysts are less efficient catalysts, which require higher concentrations. Therefore, if the preferred catalysts of the Applicant, heterogeneous elementary substances and alloys thereof, are employed, then the skilled artisan would look toward examples IV to VI of Rosenthal to begin optimization. The examples using elementary metals as the catalyst in examples V and VI employ from 0.01g to 2g of catalyst : 10 g carbamate, which corresponds to a mass ratio of (0.01-2):10, or 1:(1000-5), which also overlaps with the range in claim 1. See MPEP 2144.05. Rosenthal also teaches that the concentration of the catalyst is not particularly critical to the success of the reaction as long as a catalytic quantity is employed. See col. 7, lines 10-25.
Regarding Applicant’s arguments alleging the criticality of the claimed mass ratio of the catalyst to diphenylmethane dicarbamate, though Examples 5 and 6 show better yields of product, Examples 1 to 6 are all run using a single specific catalyst (nano copper) and solvent (p-xylene) combination. Claim 1 broadly recites “a catalyst” and “an inert solvent having a lower boiling point than the diphenyl diisocyanate”. Thus the claim is not commensurate in scope with the examples. See MPEP 2145.
Regarding Applicant’s arguments against Fujimora, though Fujimora is a two-stage process and Rosenthal is a one-stage process, the same overall transformation is occurring in both. A carbamate is being converted to an isocyanate with displacement of an alcohol, a lower boiling component of the reaction mixture than the isocyanate which requires removal. Like Rosenthal, Fujimora teaches that the by-product alcohol can be efficiently separated from the resulting reaction mixture comprising a higher boiling polyisocyanate and a heterogeneous (solid) catalyst by employing an inert low boiling point solvent with a boiling point lower than the polyisocyanate. See p. 11-12 of the OA dated 1/28/2025. Therefore, the Examiner maintains that the teachings of Fujimora provide further motivation to employ an inert solvent having a lower boiling point than the isocyanate produced in Rosenthal in the process of Rosenthal.
In response to applicant's arguments against the references individually, one cannot show nonobviousness by attacking references individually where the rejections are based on combinations of references. See In re Keller, 642 F.2d 413, 208 USPQ 871 (CCPA 1981); In re Merck & Co., 800 F.2d 1091, 231 USPQ 375 (Fed. Cir. 1986). Regarding the Applicant’s arguments against Satoyuki, Satoyuki is included only to teach that “diphenylmethane diisocyanates” can be produced from “diphenylmethane dicarbamates” by decomposition, the same overall reaction as Rosenthal and Fujimora. Rosenthal teaches that the reaction is predictable over a large genus of compounds and Fujimora teaches an example wherein a methyl polymethylene polyphenol polycarbamate is converted to the corresponding polyisocyanate, which is an oligomerized version of the reactants and products in the claimed process. Satoyuki is only used to explicitly teach the claimed reactants and products and to provide motivation to use the combined process of Rosenthal and Fujimora to produce the claimed diphenylmethane diisocyanates. The combination of Rosenthal and Fujimora teach all of the other claim limitations.
Therefore, the rejection of record is maintained.
Additionally, since the time that the last OA has issued the examiner has obtained an English translation of over Fukuoka (JPS47-158747A), which appears to render the instant claims prima facie obvious alone. Therefore, the following rejection is also introduced to teach the limitations of the newly amended claims.
Claim(s) 1, 2, 5-8, 11-13, and 15-18 is/are rejected under 35 U.S.C. 103 as being unpatentable over Fukuoka (JPS47-158747A, published on 9/30/1982, of record in the IDS filed on 2/14/2022). An English translation of Fukuoka is provided with the instant OA.
Applicant Claims
The Applicant claims were presented in the preceding rejection and incorporated by reference herein.
Determining the Scope and Content of the Prior Art (MPEP §2141.01)
Fukuoka teaches an isocyanate manufacturing method, wherein in the presence of a catalyst containing one or more elements or compounds selected from the group consisting of copper, zinc, aluminum, carbon and titanium elements in the periodic table, and oxides or sulfides of these elements, carbamic acid esters are thermally decomposed (pyrolyzed) in a solvent which is inactive to isocyanate and does not substantially dissolve the catalyst. See claim. The carbamic acid esters includes those of the following formula: R(NHCOOR’)n, which encompasses the claimed diphenylmethane dicarbamates, wherein R is diphenylmethane and n is 2. Fukuoka specifically exemplifies: “methylenebisphenylenedicarbamic acid diesters such as the dimethyl ester, diethyl ester, dibutyl ester, and diphenyl ester of 2,2-, 2,4-, or 4,4’-methylenebisphenylenedicarbamic acid”, which correspond to all of the diphenylmethane dicarbamate options in the final paragraph claim 1. See p. 3, second paragraph thru the top of p. 5. The use of these compounds as the instant diphenylmethane dicarbamate would then necessarily produce the corresponding isocyanate products of claim 11 in the pyrolysis reaction.
Fukuoka teaches that the catalysts include copper catalysts including elemental copper (Group IB/11) and oxides, sulfides, mixed oxides, or alloys thereof, including a copper-aluminum alloy (Cu-Al) as required by claims 2, 5, and 15. See second paragraph on p. 5 to the first paragraph of p. 6. Further regarding claim 16, the experimental procedure for embodiments 1 to 39 on p. 8-9 teaches that the catalyst is a powder, and copper powder is used in embodiment 1 as shown in Table 1 on p. 9. Fukuoka teaches that the mass ratio of the catalyst to carbamic acid ester may be any amount, but it is usually preferable to use the catalyst in an amount of 0.001 to 100 times by weight relative to the amount of the carbamic acid ester. See second paragraph on p. 6. This range encompasses that of claim 1. See MPEP 2144.05.
Fukuoka teaches that the reaction is run at a temperature between 100 to 350°C, preferably 150 to 300°C; at a time between several minutes to several tens of hours; and at normal, increased, or reduced pressure. See second paragraph on p. 8. All of these ranges overlap with or encompass those in claims 1, 8, 12, 17, and 18. See MPEP 2144.05.
Fukuoka teaches that the inert solvents include hydrocarbons, ethers, ketones, and esters. Preferred solvents include xylenes and mono- and di-chlorobenzenes (claims 7 and 13). See third paragraph of p. 6 to the top of p. 7.
Fukuoka teaches that the combination of the inert solvent and insoluble (heterogeneous catalyst) provides multiple benefits to the process, including the easy separation of the catalyst from the product and the suppression of high boiling point by-products. This is particularly advantageous when producing high-boiling isocyanates, including diphenylmethane diisocyanates (MDI) that are difficult to distill off by distillation or the like. See second paragraph of p. 2 to the top of p. 3 and the second paragraph of p. 7.
In the paragraph bridging p. 7-8, Fukuoka teaches the following:
“When carrying out the method of the present invention, the carbamic acid esters are converted into the corresponding isocyanates and alcohols, but in order to prevent them from recombining and returning to the carbamic acid esters, it is necessary to remove one of the components from the reaction system. In this case, it is preferable to remove and separate the low-boiling components among these components that are
generated as the reaction proceeds by distillation or the like. In order to promote this separation, it is also a preferable method to introduce an inert gas, such as nitrogen, helium, argon, carbon dioxide, methane, ethane, propane, and the like, alone or in mixture into the reaction system. Low-boiling organic solvents, such as halogenated hydrocarbons such as dichloromethane, chloroform, carbon tetrachloride, lower hydrocarbons such as pentane, hexane, heptane, and ethers such as tetrahydrofuran and dioxane, can also be used as those that have a similar effect (emphasis added).” Thus, Fukuoka teaches that the inert solvent includes alkanes and halogenated hydrocarbons and can have a lower boiling point than the diphenyl methane diisocyanate as required by claims 1 and 7.
Fukuoka teaches embodiments 1 to 39 on p. 8-9 and summarized in Table 1 on p. 9 wherein: 10 g of the dicarbamic acid diethyl ester of 4,4’-diphenylmethane diisocyanate (the ethyl diphenylmethane dicarbamate of instant claim 1) is contacted with 100 g of bromine naphthalene inert solvent (a halogenated hydrocarbon inert solvent of claim 7) and 0.5 g of a powder catalyst (including copper and derivatives thereof in embodiments 1-3 and 38 as required by claims 2, 5, 15, and 16) is heated at 250°C for 2 hours (which fall within the ranges of claims 1, 8, 12, 17, and 18) at normal pressure to produce 4,4-diphenylmethane diisocyanate (a compound of claim 11). At the end of the reaction the catalyst was separated from the reaction mixture by filtration. Based on this procedure the mass ratio of the catalyst to diphenylmethane dicarbamate is 0.5 : 10 or 1:20 and the mass ratio of the diphenylamine dicarbamate to the inert solve is 10 : 100 or 1:10 which falls within the ranges of claim 1 and 6. Also see MPEP 2144.05. In the second full paragraph on p. 10, Fukuoka teaches that the inert bromonaphthalene solvent was removed from the filtrate by distillation and then vacuum distillation was performed to obtain purified MDI. Thus, the boiling point of the bromonaphthalene solvent is lower than the diphenylmethane diisocyanate (MDI).
Ascertainment of the Difference Between Scope of the Prior Art and the Claims (MPEP §2141.02-03)
Fukuoka teaches a general process which encompasses the claimed process and embodiments 1 to 39 in the examples only differ from the process of instant claim 1 in the reaction pressure (normal pressure/0.1 MPa in Fukuoka). Fukuoka does not explicitly teach that the reaction pressure is within the range of 0.2 to 0.4 MPa.
Finding of Prima Facie Obviousness Rationale and Motivation (MPEP §2142-2143)
It would have been prima facie obvious to one of ordinary skill in the art to arrive at the instantly claimed process based on the teachings of Fukuoka with a reasonable expectation of success before the effective filing date of the claimed invention. A person of ordinary skill would have been motivated to modify the pressure of the examples of Fukuoka because Fukuoka teaches that the pyrolysis reaction can be run at increased pressure (pressure above normal pressure) and it is not inventive to optimize reactions within known ranges. Further, the lower limit of the claimed range (0.2 MPa) falls just outside of the exemplified range of Fukuoka in the examples (0.1MPa) such that both reactions should operate in substantially the same manner to produce substantially the same predictable results, all other variables being explicitly taught by Fukuoka. Also see MPEP 2144.05.
Conclusion
Any inquiry concerning this communication or earlier communications from the examiner should be directed to AMY C BONAPARTE whose telephone number is (571)272-7307. The examiner can normally be reached 11-7.
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/AMY C BONAPARTE/Primary Examiner, Art Unit 1692