DETAILED ACTION
Request for Continued Examination
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and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114.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 December 10, 2025 has been entered.
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 .
Status of the Claims
Claims 1 – 13 are pending and rejected.
Response to Applicant’s Remarks
The rejection under 35 U.S.C. §112(a) of claim 8 as failing to comply with the written description requirement is withdrawn in view of the amendments to recite proper partition coefficient (KAM/AND) in the claim.
The rejection under 35 U.S.C. §112(b) of claim 13 (claim 14 has been cancelled) is withdrawn in view of the amendments to recite the limitation “step (2A) further comprises removing the reaction solvent, the proton-donating solvent and unreacted acrylonitrile before the addition of the amine-based solvent”.
Regarding the rejection under 35 U.S.C. 103 of claims 1 – 13 (claim 14 has been cancelled) as being unpatentable over Hovey et al. US 4,639,539 A in view of Jennings et al., Applied Catalysis A: General, 1995, Vol. 124, pp. 297-315 and Tenn WO 2013/095853 A1, Applicant does not provide additional remarks in the Request for Continued Examination dated December 10, 2025. Applicant’s remarks in the response after Final action dated November 4, 2025 have been previously fully considered (see, pages 2-4 of the Advisory Action dated November 21, 2025) and addressed below:
On page 5, 4th paragraph, Applicant state the grounds for rejection rely upon the creation of an additional step that is clearly not disclosed or suggested by the cited prior art, instead of “optimization of the reaction steps”. On page 6, 1st paragraph, Applicant state that the cited prior art does not contain any recognition regarding the potential implications of the removal of solvents, and unreacted dimer reaction product separate and apart from the addition of an extraction solvent. Thus, the motivation of routine optimization is improper because the prior art does not teach the parameter as a result effective variable. On page 6, 2nd paragraph, Applicant also state that the prior art references do not contain any teachings that triethylamine would more efficiently separate and extract ethyl diphenylphosphinite and the rejection is improper based upon impermissible use of hindsight reconstruction of the prior art.
In response to applicant’s argument that there is no teaching, suggestion, or motivation in the combination of the cited prior art references, the examiner recognizes that obviousness may be established by combining or modifying the teachings of the prior art to produce the claimed invention where there is some teaching, suggestion, or motivation to do so found either in the references themselves or in the knowledge generally available to one of ordinary skill in the art. See In re Fine, 837 F.2d 1071, 5 USPQ2d 1596 (Fed. Cir. 1988), In re Jones, 958 F.2d 347, 21 USPQ2d 1941 (Fed. Cir. 1992), and KSR International Co. v. Teleflex, Inc., 550 U.S. 398, 82 USPQ2d 1385 (2007). In response to applicant's argument that the examiner's conclusion of obviousness is based upon improper hindsight reasoning, it must be recognized that any judgment on obviousness is in a sense necessarily a reconstruction based upon hindsight reasoning. But so long as it takes into account only knowledge which was within the level of ordinary skill at the time the claimed invention was made, and does not include knowledge gleaned only from the applicant's disclosure, such a reconstruction is proper. See In re McLaughlin, 443 F.2d 1392, 170 USPQ 209 (CCPA 1971). In this case, Hovey teaches the method of catalytically dimerizing acrylonitrile comprises reacting acrylonitrile in the presence of toluene (reaction solvent in the instant claims), isopropyl alcohol (proton-donating solvent in the instant claims) and isopropyl diphenyl-phosphinite (PACAT) (phosphorus-based catalyst in the instant claims). See, e.g., column 4, lines 41-63; Tables 1-3. The reaction mixture is mixed with an extraction solvent, formamide, to dissolve the catalyst and the reaction solvent, and extract the dimerized product. See, e.g., column 2, lines 41-52; and column 4, lines 41-63. Jennings et al. teach the advantage of using phosphinites, specifically Ph2POEt (ethyl diphenylphosphinite), to enhance the efficiency of the acrylonitrile dimerization reactions. Tenn further teaches that the addition of Lewis bases, amines such as triethylamines, is beneficial for the extraction of reaction mixtures comprising nitriles and phosphorous-based catalyst ligands. The teachings of Hovey et al., Jennings et al. and Tenn teach the same method for preparing acrylonitrile dimer as claimed the instant claims. A person of ordinary skill in the art would have a general knowledge of performing routine experimentation, such as optimization of the reaction steps, and remove any additional reactants and reagents (reaction solvent, proton-donating solvent and/or unreacted acrylonitrile), to assess the efficiency of the reaction conditions to separate and extract ethyl diphenylphosphinite using triethylamine. A PHOSITA would have also been motivated to decrease the amount of impurities in the final acrylonitrile dimer solution by preventing any unnecessary additional reactions with the solvents and/or reactants. Further, discovery of an optimum value of a result effective variable is not patentable if such discovery is within skill in the art. A prima facie case of obviousness may be rebutted in optimizing a variable only when results are unexpectedly good. In re Boesch, 205 USPQ 215. The selection of reaction conditions is optimization by mere modification of routine experimentation and within the purview of one skilled in the art. Therefore, Applicant’s remarks are not persuasive and the rejection is maintained. The rejection has only been amended to properly recite the pending claims and cancellation of claim 14.
Claim Interpretation
Claim 8 is directed to the method of claim 1, wherein a partition coefficient (KAM/ADN) represented by Equation 1 is 2.5 or more. According to the claim, the scope is directed towards a specific property (partition coefficient of the amine-based solvent-adiponitrile of the phosphorus-based catalyst). Equation 1 is recited to only demonstrate how the partition coefficient is calculated. Thus, reciting said mathematical formula (Equation 1) does not invoke issues with respect to patent subject matter eligibility. See, MPEP §2106.
Claim Rejections - 35 USC § 103
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 1 – 13 are rejected under 35 U.S.C. 103 as being unpatentable over Hovey et al. US 4,639,539 A (publ. 1987; effect. filed 1984) in view of Jennings et al., Applied Catalysis A: General, 1995, Vol. 124, pp. 297-315 and Tenn WO 2013/095853 A1 (pub. 2013, effect. filed 2011).
Determining the scope and contents of the prior art
Hovey et al. teach a method of catalytically dimerizing acrylonitrile in the “presence of an organic phosphorus (III) catalyst, an inert hydrocarbon reaction solvent and a non-interfering proton donating solvent; and the dimerized product separated from the catalyst by extraction”. See, e.g., Abstract; column 2, lines 41-52. Hovey specifically teaches the method comprises reacting acrylonitrile in the presence of toluene (reaction solvent in the instant claims), isopropyl alcohol (proton-donating solvent in the instant claims) and isopropyl diphenyl-phosphinite (PACAT) (phosphorus-based catalyst in the instant claims). See, e.g., column 4, lines 41-63; Tables 1-3. The reaction mixture is mixed with an extraction solvent, formamide, to dissolve the catalyst and the reaction solvent, and extract the dimerized product. See, e.g., column 2, lines 41-52; and column 4, lines 41-63.
Hovey et al. does not specifically teach the method, wherein ethyl diphenylphosphinite is specifically used as the phosphorus-based catalyst, removing the reaction solvent, the proton-donating solvent, and an unreacted acrylonitrile, and formamide is replaced with an amine-based solvent, specifically triethylamine, to extract and separate the acrylonitrile dimer.
Jennings et al. teach a method of preparing straight chain dimers comprising catalytic dimerization of acrylonitrile using homogenous catalysts from alkyl diarylphosphinites. See, e.g., Abstract. Jennings teaches that “direct addition of dialkyl or diaryl phosphinous chlorides to silica resulted in products heavily contaminated by hydrogen chloride… [r]eactions were difficult to drive to completion, and the use of tertiary amines to promote a more efficient
reaction resulted in a difficult separation of the sparingly soluble amine hydrochloride from the catalyst”. See, e.g., pp. 302-303, bridging paragraph. However, the use of phosphinites was found to be successful. The phophinites were prepared by reacting diphenyl phosphinous with isopropanol in the presence of triethylamine (amine-based solvent in the instant claims) to obtain isopropyl diphenylphosphinite. See, e.g., pp. 302-303, bridging paragraph. Further, Jennings teaches the activity of other similar phosphinite catalysts in acrylonitrile dimerization reactions as presented below (see, e.g., Table 2):
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Jennings teaches that Ph2POEt (ethyl diphenylphosphinite) obtained the highest acrylonitrile conversion (%), and catalyst productivity compared to Ph2POMe and Ph2POPri.
Tenn teaches a process for recovering diphosphite-containing compounds from a mixture comprising said compounds, organic mononitriles and organic dinitriles by using Lewis base compounds. See, e.g., Abstract, paragraphs [0006], and [0031]. The diphosphite-containing compounds can also be phosphinite compounds. See, e.g., paragraphs [0003], [0054] and [0065]. Tenn teaches that adding Lewis base compounds has been found to result in “enhanced settling of the emulsion phase… may result in the reduction of the size of the emulsion phase in the settling section”. See, e.g., paragraph [0009]. Tenn further teaches that the Lewis base “may reduce or eliminate any inhibiting effect of Lewis acid on catalyst recovery”. See, e.g., paragraph [0051]. Suitable stronger Lewis base compounds include alkyl amine, such as triethylamine. See, e.g., paragraph [0051]; and example 14.
Ascertaining the differences between the prior art and the claims at issue
Compared to claim 1, Hovey et al. does not specifically teach the method, wherein:
Ethyl diphenylphosphinite is specifically used as the phosphorus-based catalyst,
Removing the reaction solvent, the proton-donating solvent, and an unreacted acrylonitrile, and
Formamide is replaced with an amine-based solvent, specifically triethylamine, to extract and separate the acrylonitrile dimer.
Rationale for a prima face case of obviousness
According to MPEP §2141(III), two of the rationales in the KSR decision states “(A) Combining prior art elements according to known methods to yield predictable results… (G) Some teaching, suggestion, or motivation in the prior art that would have led one of ordinary skill to modify the prior art reference or to combine prior art reference teachings to arrive at the claimed invention”. KSR, 550 U.S. at 418, 82 USPQ2d at 1396. Jennings et al. teach the advantage of using phosphinites, specifically Ph2POEt (ethyl diphenylphosphinite), to enhance the efficiency of the acrylonitrile dimerization reactions. Jennings also teach converting diphenyl phosphinous chloride by reacting with isopropanol in the presence of triethylamine to prepare said phosphinites. Tenn further teaches that the addition of Lewis bases, amines such as triethylamines, is beneficial for the extraction of reaction mixtures comprising nitriles and phosphorous-based catalyst ligands. A person having ordinary skill in the art would have been motivated to select isopropyl diphenylphosphinite and ethyl diphenylphosphinite as the phosphorus-based catalysts. The PHOSITA would have performed routine experimentation, such as using amine-based solvents (specifically triethylamine) in order to separate and extract the phosphorous-based catalyst and the acrylonitrile dimer. Ph2POEt (ethyl diphenylphosphinite) obtained the highest acrylonitrile conversion (%), and catalyst productivity compared to Ph2POMe and Ph2POPri, thus the PHOSITA would have had a reasonable expectation of success that strong Lewis bases such as triethylamine would be efficient in separating said phosphorous-based catalysts in catalytic dimerization reactions of acrylonitriles.
The teachings of Hovey et al., Jennings et al. and Tenn teach the same method for preparing acrylonitrile dimer as claimed the instant claims. A person having ordinary skill in the art would have been motivated to perform routine experimentation, such as optimization of the reaction steps, and remove any additional reactants and reagents (reaction solvent, proton-donating solvent and/or unreacted acrylonitrile in the instant claims). The purpose of the routine experimentation would have been to ensure that triethylamine would more efficiently separate and extract ethyl diphenylphosphinite, while preventing any unnecessary additional reactions with the solvents and/or reactants. This would also decrease the amount of impurities in the final acrylonitrile dimer solution.
The combined teachings of the prior art would have rendered the instant claims prima facie obvious as presented below:
Claim 1, directed to a method for preparing acrylonitrile dimer comprising (1) reacting acrylonitrile in the presence of a reaction solvent, a proton-donating solvent, and a phosphorus-based catalyst to prepare an acrylonitrile dimer, removing the reaction solvent, the proton-donating solvent, and an unreacted acrylonitrile, and adding an amine-based solvent to a reaction mixture containing the acrylonitrile dimer prepared in (1) and extracting the same to separate the acrylonitrile dimer and the phosphorus-based catalyst.
Claims 2 – 3, wherein the reaction solvent is toluene.
Claims 4 – 5, wherein the proton-donating solvent is isopropyl alcohol.
Claims 6 – 7, wherein the phosphorus-based catalyst is ethyl diphenylphosphinite.
With respect to claim 8, MPEP §2112.01(I) states:
“Where the claimed and prior art products are identical or substantially identical in structure or composition, or are produced by identical or substantially identical processes, a prima facie case of either anticipation or obviousness has been established. In re Best, 562 F.2d 1252, 1255, 195 USPQ 430, 433 (CCPA 1977)”.
Since the teachings of Hovey et al., Jennings et al. and Tenn teach the same method for preparing acrylonitrile dimer as claimed the instant claims, the method would inherently possess the same partition coefficient of the amine-based solvent-adiponitrile of the phosphorus-based catalyst (KAM/AND) of 2.5 or more at 50 °C and 760 torr, as claimed in the instant claim.
Claim 10, wherein the amine-based solvent is triethylamine.
With respect to claims 11 – 12, Tenn specifically teaches that the step of adding triethylamine to the reaction mixture is performed at 65 °C for 10 mins. See, e.g., Table 1.
With respect to claim 13, the teachings of Hovey et al., Jennings et al. and Tenn teach the same method for preparing acrylonitrile dimer as claimed the instant claims. A person having ordinary skill in the art would have been motivated to perform routine experimentation, such as optimization of the reaction steps, and remove any additional reactants and reagents (reaction solvent, proton-donating solvent and unreacted acrylonitrile in the instant claims). The purpose of the routine experimentation would have been to ensure that triethylamine would more efficiently separate and extract ethyl diphenylphosphinite, while preventing any unnecessary additional reactions with the solvents and/or reactants. This would also decrease the amount of impurities in the final acrylonitrile dimer solution.
Conclusion
Any inquiry concerning this communication or earlier communications from the examiner should be directed to Sagar Patel whose telephone number is (571)272-1317. The examiner can normally be reached Monday - Friday: 9am to 5pm EST.
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/Sagar Patel/Examiner, Art Unit 1626
/KAMAL A SAEED/Primary Examiner, Art Unit 1626