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 .
Status of the Claims
Claims 1-20 are pending in the instant application and subject to examination herein.
Information Disclosure Statement
The information disclosure statement (IDS) submitted on 12/18/2025 is in compliance with the provisions of 37 CFR 1.97. Accordingly, the information disclosure statement is being considered by the examiner.
Claim Objections
Claims 19-20 are objected to because of the following informalities:
Claim 19: the compound name “6-aminocapronitrile” is misspelled as “6-amincapronitrile”;
Claim 20: the compound name “hexamethylene diisocyanate” is misspelled as “hexamethylene diisoctyanate”.
Appropriate correction is required.
Claim Rejections - 35 USC § 112(d)
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.
Claim 19 is 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 19 further limits claim 14, regarding an integrated process for converting polyamide-6 (PA6), firstly into 6-aminocaproic acid and secondly to a subsequent product that may or may not be hexamethylenediamine, by further requiring that “the 6-aminocapronitrile product”, which is to be used as a feedstock for hydrogenation to hexamethylenediamine or other subsequent chemical transformation. The claim is indefinite because a person of ordinary skill in the art cannot reasonably determine the metes and bounds of the steps required in the claimed process. The language in claim 19, that “the [6-aminocapronitrile] product further comprises adiponitrile” is unclear as to whether the claim is requiring that adiponitrile is formed from the same reaction process that forms 6-aminocapronitrile (i.e., the recycling of PA6, followed by contacting the recycling product(s) with ammonia and an aluminosilicate zeolite) or is only required to be added to the 6-aminocapronitrile prior to the reaction to form the “subsequent reaction product” which may be hexamethylenediamine or another subsequent product. The use of the term “product” as including adiponitrile suggests that adiponitrile should be formed in the same process that forms 6-aminocapronitrile; however, there is no indication in claim 14 nor anywhere in the instant disclosure that the process of contacting caprolactam with ammonia and an aluminosilica zeolite will provide adiponitrile as a product alongside 6-aminocapronitrile. The word “adiponitrile” is found three times in the Specification, and its abbreviation “ADN” is found twice. Paragraph [0088] includes “adiponitrile” and “ADN” and lists “Embodiment 19” of the instant invention which further limits “Embodiment 14” that describes the same process as claimed in instant claim 14, and “Embodiment 19” further limits “Embodiment 14” in precisely the same manner as instant claim 19 further limits instant claim 14. The word “Adiponitrile” is next listed in an underlined title preceding paragraphs [0065]-[0068], the title being “Hydrogenation of Adiponitrile and 6-aminocapronitrile”. Paragraphs [0065]-[0068] describe two experimental runs, Example 6 and Example 7, wherein hexamethylenediamine is produced by hydrogenation wherein a mixture of adiponitrile and 6-aminocapronitrile, or only 6-aminocapronitrile, respectively, are hydrogenated by contacting the reactants with hydrogen gas over a sponge nicket catalyst. These paragraphs do not explain whether the reactant feeds for Examples 6 and 7 are product(s) from the conversion of caprolactam and/or recycled PA6 or are commercially obtained reagents or otherwise procured. Thus, the instant disclosure does not provide sufficient information to understand the metes and bounds of claim 19. A search of the field of art does not provide prior example(s) of the conversion of caprolactam to adiponitrile by contact with ammonia and a solid catalyst. Thus, neither the claims nor the instant disclosure nor the field of art suffice to clarify the metes and bounds of claim 19 regarding whether the adiponitrile claimed in the claim is a “product” or merely or a reactant.
Claim Rejections - 35 USC § 102
The following is a quotation of the appropriate paragraphs of 35 U.S.C. 102 that form the basis for the rejections under this section made in this Office action:
A person shall be entitled to a patent unless –
(a)(1) the claimed invention was patented, described in a printed publication, or in public use, on sale, or otherwise available to the public before the effective filing date of the claimed invention.
(a)(2) the claimed invention was described in a patent issued under section 151, or in an application for patent published or deemed published under section 122(b), in which the patent or application, as the case may be, names another inventor and was effectively filed before the effective filing date of the claimed invention.
Claims 1 and 3-4 are anticipated by Cobb.
Claims 1 and 3-4 are rejected under 35 U.S.C. 102(a)(1) and 102(a)(2) as being anticipated by Cobb (U.S. Patent No. 3,855,267A).
Claim 1 is drawn to a process for converting caprolactam to aminocapronitrile, comprising contacting caprolactam with ammonia and an aluminosilicate zeolite catalyst, wherein the catalyst comprises less than 5 wt% of an active metal and wherein conversion of the caprolactam is greater than 50% and selectivity for aminocapronitrile as the product is greater than 91%.
Cobb discloses catalysts for the ammonialytic cleavage of lactams to w-aminonitriles (Col. 1, lines 7-10). Cobb discloses exemplary performance of the disclosed catalysts in the reaction of caprolactam with gaseous ammonia at 375°C (Example 1, Col. 3, lines 30-67 and Col. 4, lines 1-40). Cobb discloses that the reaction of caprolactam with ammonia in the presence of 13X molecular sieve, a commercially available zeolite, provides a 57% conversion of caprolactam to the corresponding w-aminonitrile (i.e., 6-aminocapronitrile) with 82% selectivity. When the 13X molecular sieve is loaded with aluminum phosphate as a catalyst, the conversion rate rises to 60% and the selectivity improves to 100%. Cobb does not specifically disclose that 13X molecular sieves are an aluminosilicate zeolite; however, a person of ordinary skill in the art would at once recognize that 13X molecular sieves is an aluminosilicate zeolite with a silica to alumina ratio (SAR) of less than 2, because this material is well-known in the art, as evidenced by Sigma-Aldrich1.
Thus, claim 1 is anticipated by the disclosure of Cobb.
Claim 3 further limits claim 1 to wherein the aluminosilicate zeolite has an SAR of less than 200, and is met by the disclosure of Cobb.
Claim 4 further limits claim 1 to wherein the reaction is conducted at a temperature ranging from 350-375°C, and is met by the disclosure of Cobb.
Thus, claims 3-4 are anticipated by the disclosure of Cobb.
Claims 1-3 and 6 are anticipated by Wang.
Claims 1-3 and 6 are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Wang (CN111574401A).
The limitations of claims 1 and 3 are discussed in the rejection above and hereby incorporated into the instant rejection.
Wang discloses a continuous gas-phase process for the production of “6-aminohexanonitrile” (i.e., 6-aminocapronitrile) comprising contacting caprolactam with gaseous ammonia and a first solid catalyst, then pumping the reaction mixture and ammonia over a second solid catalyst to obtain the desired product (paragraphs [0007]-[0014]). Wang discloses that the first solid catalyst can be ZSM-5, which performs a hydrolysis-ammoniation reaction (paragraph [0029]). Wang also discloses that in the first step, the hydrolysis-ammoniation reaction converts caprolactam to a product or product mixture containing 6-aminohexanoic acid, ammonium salt of 6-aminohexanoic acid, and/or 6-aminohexanamide, and in the second step, the initial product/mixture is converted to 6-aminohexanonitrile (paragraphs [0020]-[0024]). Wang discloses several examples wherein caprolactam is contacted with ammonia and ZSM-5 in the process that produces 6-aminohexanonitrile, including Example 2 (paragraphs [0038]-[0039]). Wang discloses that in Example 2, the yield of the conversion is 97.1% and the selectivity for 6-aminohexanonitrile is up to 97% for up to 1400 hours of continuous use of the catalyst (paragraph [0039]). Wang does not disclose that ZSM-5 is an aluminosilicate zeolite; however, a person of ordinary skill in the art would at once recognize that ZSM-5 is an aluminosilicate zeolite, as ZSM-5 is a well-known material, as evidenced by Wikipedia2.
Thus, claim 1 is anticipated by the disclosure of Wang.
Claim 2 further limits claim 1 to wherein the aluminosilicate zeolite catalyst comprises less than 1 wt% phosphorus. ZSM-5 is a well-known aluminosilicate zeolite, with a molecular formula of NanAlnSi96-nO192·16H2O (0<n<27), as evidenced by Wikipedia. Thus, phosphorus is not a component of ZSM-5, and Wang does not disclose any doping of ZSM-5 with phosphorus.
Claim 3 further limits claim 1 to wherein the SAR ratio of the aluminosilicate zeolite is less than 200. As per the molecular formula of ZSM-5 shown above, the maximum SAR for ZSM-5 is 95.
Claim 6 further limits claim 1 to wherein the 6-aminocapronitrile contains less than 10wt% impurities, and is met by the rejection above.
Thus, claims 2-3 and 6 are anticipated by the disclosure of Wang.
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.
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.
Claims 1-3 and 5-12 are unpatentable over Wang.
Claims 1-3 and 5-12 are rejected under 35 U.S.C. 103 as being unpatentable over Wang (CN111574401A).
The limitations of claims 1-3 and 6 and the disclosure of Wang are discussed in the rejection above and hereby incorporated into the instant rejection.
Claim 5 further limits claim 1 to wherein the caprolactam feed comprises from 100 ppm to 1 wt% impurity(s), with the impurity(s) selected from a Markush group that includes 6-aminocaproic acid (i.e., 6-aminohexanoic acid).
Claim 7 is drawn to a gas-phase process for converting caprolactam to 6-aminocapronitrile comprising contacting a caprolactam feed with ammonia and a catalyst, wherein the conversion of the caprolactam is greater than 50% and selectivity for 6-aminocapronitrile as the product is greater than 91%, and wherein the caprolactam comprises
from 100 ppm to 40 wt% impurity(s), with the impurity(s) selected from a Markush group that includes 6-aminocaproic acid (i.e., 6-aminohexanoic acid).
As discussed in the rejection above, Wang discloses a continuous gas-phase process for the production of “6-aminohexanonitrile” (i.e., 6-aminocapronitrile) comprising contacting caprolactam with gaseous ammonia and a first solid catalyst, which can be the known aluminosilicate zeolite ZSM-5, then pumping the reaction mixture and ammonia over a second solid catalyst to obtain the desired product (paragraphs [0007]-[0014]), and Wang discloses that the process converts caprolactam into the intermediate 6-aminocaproic acid and/or the ammonium salt thereof, and that the process converts the 6-aminocaproic acid or ammonium salt thereof into 6-aminohexanamide then finally dehydrating the 6-aminohexanamide into the desired product 6-aminocapronitrile within the yield and selectivity limits of claims 1 and 7 (paragraphs [0020]-[0024] and [0038]-[0039]).
Wang does not disclose that the caprolactam feed may contain impurity(s) from 1 ppm to 1 wt% or up to 40 wt% in content; however, a person of ordinary skill in the art would have a reasonable expectation of success in using a caprolactam feed with an impurity of 6-aminocaproic acid of 1 ppm up to 1 wt% or even up to 40 wt% in content, because Wang discloses that 6-aminocaproic acid is an intended intermediate in the reaction process disclosed therein and is consumed in the production of the intended product 6-aminocapronitrile (paragraphs [0020]-[0024]).
Applicant’s invention is unpatentable over the disclosure of Wang, because a person of ordinary skill in the art, at the effective time of filing, would have a reasonable expectation of success in using the invention of Wang with an impure feed of caprolactam comprising from 1 ppm to 1 wt% or up to 40 wt%, or indeed any wt% content of 6-aminocaproic acid, because Wang discloses that 6-aminocaproic acid is an intermediate of the process disclosed therein and is further converted to the desired product 6-aminocapronitrile.
Thus, the invention was prima facie obvious at the time of filing.
Claim 8 further limits claim 7 to wherein the impurity(s) comprise less than 10 wt% of low boiling impurities having a boiling point below 255°C, measured at atmospheric pressure. Claim 10 further limits claim 17 to wherein the impurity(s) comprise less than 20 wt% of high boiling point impurity(s) having a boiling point greater than 270°C. An impurity of 6-aminocaproic acid at any wt% inherently meets these limitations as the boiling point of 6-aminocaproic acid is ~255.6°C, as evidenced by the chemical supplier CarlRoth (Safety Data Sheet, 6-aminohexanoic acid, CarlRoth; date of compilation: 02/19/2016; version 4.0, revision 09/17/2024) as well as provided in the instant disclosure, wherein 6-aminohexanoic acid is defined as an “intermediate boiling point” impurity having a boiling point in the range of 255-270°C (paragraph [0033]).
Claim 9 further limits claim 7 to wherein the caprolactam impurity comprises less than 10 wt% of an intermediate boiling point impurity. An impurity of 6-aminocaproic acid, any at wt%, including less than 10 wt%, would be reasonable to include in a caprolactam feed for Wang’s process of converting caprolactam to 6-aminocapronitrile, because Wang discloses that 6-aminocaproic acid is an intermediate in the process and is further converted to 6-aminocapronitrile.
Claim 11 further limits claim 7 to wherein the caprolactam impurity comprises recycled polyamide-6, or 6-aminocaproic acid, or a mixture thereof, and is met by the rejection above.
Claim 12 further limits claim 7 to wherein the 6-aminocapronitrile product comprises less than 10 wt% impurities. As disclosed above, Wang’s “Example 2” demonstrates 97.1% conversion of caprolactam with up to 97% selectivity of 6-aminocapronitrile as the product (paragraph [0039]). A person of ordinary skill in the art would at once envisage that an impurity in the caprolactam that comprises 6-aminocaproic acid, an intermediate formed in the very same process, would result in comparable yield/selectivity of the intended product.
Applicant’s invention is unpatentable over the disclosure of Wang, because a person of ordinary skill in the art, at the effective time of filing, would have a reasonable expectation of success in using the invention of Wang’s gas-phase process to prepare 6-aminocapronitrile by contacting caprolactam with ammonia and ZSM-5 aluminosilicate zeolite, wherein the caprolactam feed comprises an impurity of 6-aminocaproic acid, an intermediate boiling impurity having an estimated boiling point of 255.6°C, within a range of 1 ppm to 1 wt% or even up to 40 wt% content, and achieving equivalent result in yield/selectivity as using pure caprolactam, because Wang discloses that 6-aminocaproic acid is an intermediate of the process disclosed therein and is further converted to the desired product 6-aminocapronitrile.
Thus, the invention was prima facie obvious at the time of filing.
Claims 1-3 and 5-13 are unpatentable over Wang in view of Ottenheym.
Claims 1-3 and 5-13 are rejected under 35 U.S.C. 103 as being unpatentable over Wang in view of Ottenheym (U.S. Patent No. 2,900,310).
The limitations of claims 1-3 and 5-12 and the disclosure of Wang are discussed in the rejections above and hereby incorporated into the instant rejection.
Claim 13 further limits claim 7 to wherein the 6-aminocapronitrile product is further purified by distillation.
Wang does not disclose the further purification of the 6-aminocapronitrile obtained from the process disclosed therein. However, a person of ordinary skill in the art would have a reasonable expectation of success in further purifying 6-aminocapronitrile obtained in the process disclosed by Wang by distilling the obtained product mixture, because it was known in the art that 6-aminocapronitrile is susceptible to purification by distillation under reduced pressure, particularly in the separation of 6-aminocapronitrile formed from conversion of caprolactam, per the disclosure of Ottenheym.
Ottenheym discloses a method for efficiently separating 6-aminocapronitrile from caprolactam and water, particularly suitable for purifying 6-aminocapronitrile formed by conversion of caprolactam by reaction with ammonia (Col. 1, lines 15-29). Ottenheym discloses that adding an inert solvent that forms an azeotrope with water to a mixture comprising 6-aminocapronitrile, caprolactam and water results in an efficient separation of 6-aminocapronitrile, caprolactam and water wherein the mass recovery of 6-aminocapronitrile is greatly improved over the amount recovered when the three-component mixture is distilled without the azeotrope-forming added solvent (Col. 1, lines 39-47). Ottenheym provides examples of reduced pressure distillation of 6-aminocapronitrile/caprolactam and 6-aminocapronitrile/caprolactam/water mixtures to show the reduced recovery of 6-aminocapronitrile in the presence of water, and the improved recovery of 6-aminocapronitrile when benzene is added to draw off the water in an azeotrope (Example 1, Col. 3, lines 1-36). Ottenheym also provides an exemplary conversion of caprolactam to 6-aminocapronitrile by reaction of caprolactam with ammonia over a solid catalyst comprising alumina at 340°C, followed by purification of the reaction mixture by addition of benzene and distillation at reduced pressure to isolate 6-aminocapronitrile from caprolactam and other residue (Example 2, Col. 3, lines 37-60).
Applicant’s invention is unpatentable over the disclosure of Wang in view of the disclosure of Ottenheym, because a person of ordinary skill in the art would have a reasonable expectation of success in using the high-yield and selective process disclosed by Wang to convert caprolactam to 6-aminocapronitrile and further purifying the obtained product mixture by distillation, because Ottenheym discloses that 6-aminocapronitrile can be efficiently separated from caprolactam, water and other impurities, including after a reaction converting caprolactam to 6-aminocapronitrile, by addition of an inert solvent that forms an azeotrope with water and distillation of the resulting mixture under reduced pressure.
Thus, the invention was prima facie obvious at the time of filing.
Claims 1-3, 5-8, 10-12, 14-15 and 18 are unpatentable over Wang in view of Kopietz and Lasier.
Claims 1-3, 5-8, 10-12, 14-15 and 18 are rejected under 35 U.S.C. 103 as being unpatentable over Wang in view of Kopietz (U.S. Patent No. 5,455,346) and Lasier (U.S. Patent No. 2,234,566).
The limitations of claims 1-3, 5-8 and 10-12 and the disclosure of Wang are discussed in the rejections above and hereby incorporated into the instant rejection.
Claim 14 is drawn to an integrated process for converting polyamide-6 (PA6) to hexamethylenediamine, comprising the following:
Depolymerizing a stream comprising PA6 and impurities to produce a depolymerized stream comprising caprolactam monomers, dimers, oligomers, or combinations thereof;
Contacting the depolymerized stream with ammonia and an aluminosilicate zeolite catalyst comprising less than 5 wt% of an active metal to produce 6-aminocapronitrile;
Optionally reacting the 6-aminocapronitrile product to produce hexamethylenediamine;
Reacting the 6-aminocapronitrile product or the optionally-produced hexamethylenediamine product to form a subsequent reaction product.
Claim 15 further limits claim 14 to wherein the impurity(s) within the caprolactam stream is/are selected from a Markush group that includes 6-aminocaproic acid.
Claim 18 further limits claim 14 to wherein the reacting comprises hydrogenating the 6-aminocapronitrile product in the presence of a nickel-based catalyst to produce hexamethylenediamine.
As discussed in the rejection above, Wang discloses that 6-aminocaproic acid is an intermediate in the conversion of caprolactam to 6-aminocapronitrile, and therefore a mixture of caprolactam with 6-aminocaproic acid would be a suitable caprolactam feed for the process disclosed therein. Wang does not disclose that the caprolactam feed to be used in the process of forming 6-aminocapronitrile can be depolymerized PA6, nor the formation of hexamethylenediamine by further reaction of the produced 6-aminocapronitrile. However, a person of ordinary skill in the art would have a reasonable expectation of success in forming an integrated process wherein PA6 is depolymerized and the reaction mixture thereby produced is fed into the process of Wang to further produce 6-aminocapronitrile, which is then subjected to a subsequent reaction to form hexamethylenediamine, because it was known in the art that depolymerization of PA6 by hydrolysis at elevated pressure can produce a mixture of caprolactam and 6-aminocaproic acid, per the disclosure of Kopietz, and it was known in the art that 6-aminocapronitrile can be hydrogenated with Raney nickel to form a further reaction product that is hexamethylenediamine, per the disclosure of Lasier.3
Kopietz discloses processes for obtaining caprolactam from mixtures which contain polymers or thermoplastic molding materials having the repeating unit –(N(H)-(CH2)5-C(O)-)- by (a) cleavage at elevated temperatures in the presence of a base under reduced pressure or (b) in the presence of water (Col. 1, lines 5-12). Kopietz provides “Example 1” wherein a sample of PA6 is combined with sodium hydroxide in an autoclave and heated to 280°C at 20 kPa. After a reaction time of 2 hours, caprolactam was obtained from the reaction mixture by distillation (Col. 4, lines 30-39). Kopietz further provides “Example 10” wherein a sample of PA6 is heated to 310°C with water for 1.5 hours. Caprolactam (74% yield) and aminocaproic acid (8% yield) were then removed from the reaction mixture by distillation (Col. 5, lines 24-30). Thus, Kopietz discloses a manner for obtaining caprolactam by depolymerization of PA6.
Lasier discloses a catalytic process for the overall conversion of cyclohexanone oxime to hexamethylenediamine via the intermediate 6-aminocapronitrile (Cols. 1-2, bridging paragraph). Lasier provides “Example 2”, wherein cyclohexanone oxime is combined with ammonia and passed over silica gel at 250°C, providing two liquid layers (Col. 2, lines 47-53): the oil layer is further purified by distillation to yield hexen-5-nitrile (Col. 2, lines 53-55), while the aqueous layer is extracted with ether, concentrated and distilled to yield 6-aminocapronitrile and caprolactam (Col. 3, lines 2-9); the caprolactam is further reacted with ammonia over a solid catalyst (copper on silica gel) and distilled to yield further 6-aminocapronitrile (Col. 3, lines 12-20); lastly, the accumulated 6-aminocapronitrile is hydrogenated over Raney nickel to provide hexamethylenediamine (Col. 3, lines 27-29). Thus, Lasier discloses the conversion of 6-aminocapronitrile to hexamethylenediamine.
Applicant’s invention is unpatentable over the disclosure of Wang in view of the disclosures of Kopietz and Lasier, because a person of ordinary skill in the art, at the effective time of filing, would have a reasonable expectation of success in conducting an integrated process for the overall conversion of PA6 to hexamethylenediamine by feeding caprolactam obtained by depolymerization of PA6 into the process of Wang to prepare 6-aminocapronitrile, and to further reduce the 6-aminocapronitrile to form hexamethylenediamine by hydrogenation with Raney nickel, because it was known in the art that the hydrolytic depolymerization of PA6 can produce caprolactam, alone in a mixture with 6-aminocaproic acid, per the disclosure of Kopietz, and it was known in the art that these components correspond to the starting material and reaction intermediate to form 6-aminocapronitrile by hydrolytic ammoniation and subsequent dehydration of caprolactam, per the disclosure of Wang, and it was known in the art that 6-aminocapronitrile can be reduced to hexamethylenediamine by hydrogenation over Raney nickel, per the disclosure of Lasier.
Thus, the invention was prima facie obvious at the time of filing.
Claims 1-3, 5-12, 14-16 and 18 are unpatentable over Wang in view of Kopietz and Lasier, and further in view of Yoshida.
Claims 1-3, 5-12, 14-16 and 18 are rejected under 35 U.S.C. 103 as being unpatentable over Wang in view of Kopietz and Lasier, and further in view of Yoshida (JP2008-255554A).
The limitations of claims 1-3, 5-8, 10-12, 14-15 and 18, and the disclosures of Wang, Kopietz and Lasier are discussed in the rejections above and hereby incorporated into the instant rejection.
Claim 9 further limits claim 7, regarding a gas-phase process for converting an impure feedstock of caprolactam into 6-aminocapronitrile, to wherein the impurity(s) comprise less than 10 wt% of intermediate boiling point impurity(s) having a boiling point ranging from 255-270°C as measured at atmospheric pressure, a limitation which includes 6-aminocaproic acid.
The depolymerization of PA6 disclosed by Kopietz is accomplished by reacting a 10:1 ratio of water to PA6 by mass at 310°C, and provides a 74% yield of 6-aminocapronitrile, an 8% yield of 6-aminocaproic acid, and a 2% yield of caprolactam oligomer(s) and separates these components from each other by distillation (Col. 5, lines 24-30). Using the 6-aminocapronitrile and 6-aminocaproic acid together, or the ternary mixture of these products together, as the caprolactam feed for the process of Wang would comprise a ~10 wt% content of 6-aminocaproic acid in the feedstock. However, a person of ordinary skill in the art would have a reasonable expectation of success in obtaining a caprolactam feed containing less than 10% of 6-aminocaproic acid by modifying the water-to-PA6 and reaction temperature, because it was known in the art that reacting water and PA6 in a 16:1 ratio at 350°C can provide a caprolactam product containing less than 10% 6-aminocaproic acid, per the disclosure of Yoshida.
Yoshida discloses methods for depolymerizing fabrics with subcritical water (Abstract). Yoshida discloses the exemplary depolymerization of Nylon 6 (PA6) by combining 1 part Nylon 6 and 16 parts water, by mass, in a reaction tube and heating to 350°C for 10 minutes (paragraph [0032]).Yoshida provides Figure 7 showing a yield/time graph of the consumption of Nylon 6 during the reaction (solid circles), total production of isolable organic products (solid triangles), and individual proportions of caprolactam (hollow circles) and 6-aminocaproic acid (solid squares). After ten minutes of reaction, an overall conversion of just over 60% is achieved, with 6-aminocaproic acid comprising just under 10% of the proportional yield of caprolactam as shown by Figure 7. Thus Yoshida shows that tuning the water-to-polymer mass ratio and the temperature achieves a complete depolymerization of Nylon 6 to provide a caprolactam feedstock with less than 10% of 6-aminocaproic acid.
Applicant’s invention is unpatentable over the disclosure of Wang in view of the disclosures of Kopietz and Lasier, and further in view of the disclosure of Yoshida, because a person of ordinary skill in the art, at the effective time of filing, would have a reasonable expectation of success in using the invention of Wang, wherein the caprolactam feed, comprising caprolactam and a <10 wt% impurity of 6-aminocaproic acid, is obtained by depolymerization of PA6, and the obtained 6-aminocapronitrile is reduced by hydrogenation over Raney nickel to produce hexamethylenediamine, because it was known in the art how to depolymerize PA6 to prepare caprolactam containing ~10 wt% 6-aminocaproic acid, per the disclosure of Kopietz, and it was known in the art that by using a different water-to-PA6 ratio and different temperature, PA6 can be depolymerized to form a caprolactam product containing <10 wt% impurity of 6-aminocaproic acid, per the disclosure of Yoshida, and it was known in the art how to form hexamethylenediamine by hydrogenation of 6-aminocapronitrile acid over Raney nickel, per the disclosure of Lasier.
Thus, the invention was prima facie obvious at the time of filing.
Claims 1-3, 5-8, 10-15 and 17-18 are unpatentable over Wang in view of Kopietz and Lasier, and further in view of Ottenheym.
Claims 1-3, 5-8 and 10-15 and 17-18 are rejected under 35 U.S.C. 103 as being unpatentable over Wang in view of Kopietz and Lasier, and further in view of Ottenheym.
The limitations of claim 1-3, 5-8, 10-15 and 18 and the disclosures of Wang, Kopietz, Lasier and Ottenheym are discussed in the rejections above and hereby incorporated into the instant rejection.
Claim 13 further limits claim 7 to wherein the 6-aminocapronitrile product is further purified by distillation.
Claim 17 further limits claim 14 to wherein the 6-aminocaprile product obtained from caprolactam conversion is further purified by distillation.
Wang does not disclose the further purification of the 6-aminocapronitrile obtained from the process disclosed therein. However, a person of ordinary skill in the art would have a reasonable expectation of success in further purifying 6-aminocapronitrile obtained in the process disclosed by Wang by distilling the obtained product mixture, because it was known in the art that 6-aminocapronitrile is susceptible to purification by distillation under reduced pressure, particularly in the separation of 6-aminocapronitrile formed from conversion of caprolactam, per the disclosure of Ottenheym.
Ottenheym discloses a method for efficiently separating 6-aminocapronitrile from caprolactam and water, particularly suitable for purifying 6-aminocapronitrile formed by conversion of caprolactam by reaction with ammonia (Col. 1, lines 15-29). Ottenheym discloses that adding an inert solvent that forms an azeotrope with water to a mixture comprising 6-aminocapronitrile, caprolactam and water results in an efficient separation of 6-aminocapronitrile, caprolactam and water wherein the mass recovery of 6-aminocapronitrile is greatly improved over the amount recovered when the three-component mixture is distilled without the azeotrope-forming added solvent (Col. 1, lines 39-47). Ottenheym provides examples of reduced pressure distillation of 6-aminocapronitrile/caprolactam and 6-aminocapronitrile/caprolactam/water mixtures to show the reduced recovery of 6-aminocapronitrile in the presence of water, and the improved recovery of 6-aminocapronitrile when benzene is added to draw off the water in an azeotrope (Example 1, Col. 3, lines 1-36). Ottenheym also provides an exemplary conversion of caprolactam to 6-aminocapronitrile by reaction of caprolactam with ammonia over a solid catalyst comprising alumina at 340°C, followed by purification of the reaction mixture by addition of benzene and distillation at reduced pressure to isolate 6-aminocapronitrile from caprolactam and other residue (Example 2, Col. 3, lines 37-60).
Applicant’s invention is unpatentable over the disclosure of Wang in view of the disclosures of Kopietz and Lasier and further in view of the disclosure of Ottenheym, because a person of ordinary skill in the art, at the effective time of filing, would have a reasonable expectation of success in using the invention of Wang to convert a caprolactam feed to 6-aminocapronitrile by contact with ammonia and an aluminosilicate feedstock, wherein the caprolactam feed is obtained by depolymerization of PA6, and the obtained 6-aminocapronitrile is further purifying by distillation and then reduced by hydrogenation over Raney nickel to produce hexamethylenediamine, for the following reasons:
It was known in the art how to depolymerize PA6 to prepare caprolactam containing 6-aminocaproic acid, per the disclosure of Kopietz;
It was known in the art how to convert caprolactam to 6-aminocapronitrile by a process comprising contacting caprolactam with ammonia and ZSM-5 solid catalyst, per the disclosure of Wang;
It was known in the art how to further purify 6-aminocapronitrile by preliminary removal of water content from the mixture by adding an inert solvent that forms an azeotrope with water (e.g., benzene) and removing the azeotrope before distillation, per the disclosure of Ottenheym;
And it was known in the art how to form hexamethylenediamine by hydrogenation of 6-aminocapronitrile acid over Raney nickel, per the disclosure of Lasier,
Thus, the invention was prima facie obvious at the time of filing.
Claims 1-3, 5-8, 10-12, 14-15, 18 and 20 are unpatentable over Wang in view of Kopietz and Lasier, and further in view of Monster
Claims 1-3, 5-8, 10-12, 14-15, 18 and 20 are rejected under 35 U.S.C. 103 as being unpatentable over Wang in view of Kopietz and Lasier, and further in view of Monster (WO 2014/179070 A1).
The limitations of claims 1-3, 5-8, 10-12, 14-15 and 18 and the disclosures of Wang, Kopietz and Lasier are discussed in the rejections above and hereby incorporated into the instant rejection.
Claim 20 further limits claim 14 to wherein “subsequent reaction product” formed from 6-aminocapronitrile and/or hexamethylenediamine comprises reacting hexamethylenediamine to form a polyamide other than PA6, for example PA6,6 (polyamide 6,6, also known as Nylon 66).
Wang discloses that hexamethylenediamine is mainly used in the production of Nylon 66 and Nylon 610, and can also be used to synthesize 1,6-hexanediisocyanate, of which more than 85% is used in the production of Nylon 66 (paragraph [0002]). Wang does not provide a process for the production of Nylon 66 from hexamethylenediamine; however, a person of ordinary skill in the art would have a reasonable expectation of success in producing Nylon 66 from hexamethylenediamine, because it was known in the art how to react hexamethylenediamine with adipic acid to form Nylon 66, per the disclosure of Monster.
Monster discloses methods and apparatuses providing uniform polyamide pellets (Abstract). Monster discloses “Example 1”, wherein Nylon 66 is prepared by charging an autoclave with an aqueous solution of adipic acid and hexamethylenediamine and raising the temperature within the autoclave to 280°C and carrying out polymerization according to cyclic processing (page 21, lines 9-19). Monster discloses that cyclic processing refers to conducting the polymerization across 5 steps or “cycles” wherein the pressure inside the reaction vessel rises (cycle 1), is held stable at the elevated pressure (cycle 2), is reduced back to a lower pressure (cycle 3), is held stable at the lower pressure (cycle 4) and then polymer is extruded from the vessel (cycle 5) (pages 7-8, bridging paragraph). Monster further provides diagrams for exemplary autoclaves (Figures 1A and 1B) and the overall equipment setup for the process of forming the polymer, extruding the polymer, and cutting the extruded polymer into regular-sized pellets (Figure 2). Thus, Monster provides the chemical process and physical requirements for making Nylon 66 from hexamethylenediamine.
Applicant’s invention is unpatentable over the disclosure of Wang in view of the disclosures of Kopietz and Lasier, and further in view of the disclosure of Monster, because a person of ordinary skill in the art would have a reasonable expectation of success in using the invention of Wang, wherein the caprolactam feed is obtained by depolymerization of PA6, and the obtained 6-aminocapronitrile is reduced by hydrogenation over Raney nickel to produce hexamethylenediamine, and then subsequently polymerizing the hexamethylenediamine together with adipic acid to form Nylon 66, because it was known in the art how to depolymerize PA6 to prepare caprolactam containing 6-aminocaproic acid, per the disclosure of Kopietz, and it was known in the art how to form hexamethylenediamine by hydrogenation of 6-aminocapronitrile acid over Raney nickel, per the disclosure of Lasier, and it was known in the art how to prepare Nylon 66 from a mixture of hexamethylenediamine and adipic acid, per the disclosure of Monster.
Thus, the invention was prima facie obvious at the time of filing.
Conclusion
Any inquiry concerning this communication or earlier communications from the examiner should be directed to W. JUSTIN YOUNGBLOOD whose telephone number is (703)756-5979. The examiner can normally be reached on Monday-Thursday from 8am to 5pm. The examiner can also be reached on alternate Fridays.
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/W.J.Y./Examiner, Art Unit 1629
/JEFFREY S LUNDGREN/Supervisory Patent Examiner, Art Unit 1629
1 https://www.sigmaaldrich.com/US/en/substance/molecularsieves13x1234563231696, archived by the Internet Wayback Machine on 10/21/2021; accessed by Examiner on 01/05/2025.
2 https://en.wikipedia.org/wiki/ZSM-5, archived by the Internet Wayback Machine on 05/07/2021; accessed by Examiner on 01/05/2025.
3 The Examiner notes that the further reaction of 6-aminocapronitrile to form hexamethylenediamine satisfies both the optional further conversion shown as step “2a” in the outline of the process of claim 14 shown above and the required step “3” of the process.