DETAILED ACTION
Claim Objections
Claim 21 is objected to because of the following informalities: step (F) should be indented to be in line with step (E) and not sub-steps (a)-(c). Appropriate correction is required.
Claim Rejections - 35 USC § 112
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 1-26 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.
Regarding claims 1, 17 and 21, step (I), (i), and (A), respectively, states “a feed mixture comprising one or more xylene isomers” (emphasis added, thus encompassing an embodiment wherein only one xylene isomer is present in the feed) and step (II), (ii), and (B), respectively, requires separation of the feed mixture into a p-xylene product stream and a raffinate stream comprising o-xylene and/or m-xylene. Therefore, based on step (II), (ii), and (B), it appears that the feed mixture must comprise at least two xylene isomers: (1) p-xylene and (2) o-xylene and/or m-xylene. The discrepancy between the requirements of these two steps makes it unclear the nature of the feed mixture being separated and the resulting streams separated therefrom. For the purposes of examination, the office has interpreted the claims to require a feed mixture comprising p-xylene and at least one of o-xylene and m-xylene.
Regarding claim 17, step (iii) states “conducting liquid-phase isomerization…upon at least a portion of the raffinate stream” and step (v) states “feeding a portion of the raffinate stream to a second side of the divided wall distillation column.” Given that step (v) requires acting on a portion of the raffinate stream, recitation of “at least a portion of the raffinate stream” in step (iii) is unclear, given that it encompasses sending all of the raffinate stream to isomerization.
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.
Claims 1, 3, 4, 8-11, 14, 16, 21-23 and 25 are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Salciccioli et al (US 2018/0002252), as evidenced by Mlinar et al (US 10,703,691).
Regarding claims 1, 4, 8, 10, 11, 16, 21-23, Salciccioli discloses a process comprising (see Fig. 2):
(I)/(A) providing a feed mixture 112 comprising xylene isomers including p-xylene (PX), ethylbenzene (EB), and at least one of o-xylene (OX) and m-xylene (MX) (see [0013]);
(II)/(B) separating the feed mixture in a p-xylene recovery unit 120 using simulated bed chromatography with a desorbent to obtain a product stream 122 rich in p-xylene and a raffinate stream 126 lean in p-xylene, the raffinate stream comprising desorbent, ethylbenzene, and o-xylene, m-xylene, or any combination thereof (see [0013]; [0024]; [0029]);
(IV)/(C) separating at least a portion of the raffinate stream in a distillation column 130 to obtain a desorbent stream 134 and a stream 132 comprising one or more xylene isomers (see [0037]);
(V)/(D) feeding the desorbent stream to the p-xylene recovery unit (see [0037]);
(VI)/(E) conducting liquid-phase isomerization 140 under liquid-phase isomerization conditions in the presence of an isomerization catalyst and obtaining an isomerized recycle stream 142, the liquid-phase isomerization being conducted upon the stream comprising one or more xylene isomers obtained from separation step (IV) (see [0037]-[0041], thus “a portion of the raffinate stream” as in claims 4 and 23); and
(VII)/(F) feeding at least a portion of the isomerized recycle stream to the p-xylene recovery unit (see [0041]).
Salciccioli does not explicitly disclose that separation in step (IV)/(C) results in an overhead stream comprising the desorbent and a lower stream comprising the xylene isomer(s). Rather, the opposite configuration is depicted in Fig. 2.
However, the office notes that locations at which the aforementioned streams are removed from the distillation column depend on their boiling points relative to one another. In this regard, the office notes that Salciccioli discloses toluene as a suitable desorbent (see [0034]). In such embodiment, the distillative separation would result in toluene being removed as the overhead stream and the xylene isomers being removed as a bottom stream, as evidenced by Mlinar:
Mlinar, like Salciccioli, discloses recovery of p-xylene in a process comprising simulated moving bed adsorption 20 followed by distillation 35 to separate desorbent 45, 55 from raffinate 40, 60 comprising xylene isomers. Mlinar discloses that light or heavy desorbents may be employed, where toluene is a light desorbent and results in being separated as an overhead stream in the distillation column, whereas heavy desorbents exit via a bottom stream (see Figs. 1A,B; col. 1, lines 37-42; col. 2, lines 5-25; col. 5, lines 7-8).
Thus, in the embodiment where toluene is used as the desorbent in Salciccioli’s process, the reference is considered to anticipate the claimed process, as evidenced by Mlinar.
Regarding claims 3 and 25, Salciccioli discloses the isomerization catalyst comprising a zeolite having MEL or MFI framework (see [0040], including ZSM-11 and ZSM-5).
Regarding claim 9, Salciccioli discloses wherein the isomerized raffinate 142 is not fed to the distillation column 130 (see Fig. 2).
Regarding claim 14, Salciccioli discloses wherein the feed mixture comprises 20 wt.% or less ethylbenzene (see Tables 2, 4).
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 2 and 26 are rejected under 35 U.S.C. 103 as being unpatentable over Salciccioli, as applied to the claims above, in view of Dreux et al (US 2017/0210682).
Regarding claims 2 and 26, Salciccioli does not disclose conducting vapor phase isomerization upon at least a portion of the one or more lower streams.
Dreux, like Salciccioli, is directed to the production of p-xylene from a xylenes cut using simulated moving bed separation followed by distillation of raffinate(s). An intermediate raffinate stream obtained from distillation, comprising ethylbenzene, is directed to a vapor phase isomerization reactor operated under vapor-phase isomerization conditions in the presence of a catalyst (see Fig. 2; [0030]-[0038]; [0050]-[0056]; [0094]). Dreux discloses the process being suitable for increasing the quantity of paraxylene produced (see [0173]).
It would have been obvious to a person of ordinary skill in the art at the time of filing the instant claimed invention to modify the process of Salciccioli to include a step of vapor phase isomerization upon at least a portion of a lower stream, e.g., comprising ethylbenzene, as suggested by Dreux, in order to increase the quantity of p-xylene produced.
Claims 5 and 15 are rejected under 35 U.S.C. 103 as being unpatentable over Salciccioli, as applied to the claims above.
Regarding claim 5, Salciccioli differs from the claimed embodiment in that distillation precedes isomerization, instead of the other way around, as claimed. Nevertheless, selection of any order of performing process steps is prima facie obvious in the absence of new or unexpected results. In re Burhans, 154 F.2d 690, 69 USPQ 330 (CCPA 1946).
Regarding claim 15, Salciccioli does not explicitly disclose the concentration of desorbent (toluene) in the raffinate stream. However, the concentration of toluene in the raffinate depends on the amount of desorbent added to the p-xylene recovery unit and the separation efficiency therein. A person of ordinary skill in the art would optimize these conditions in order to achieve the objective of maximizing separation efficiency of p-xylene from the feed mixture. Absent a showing of criticality or unexpected results, the claimed concentration of toluene in the raffinate stream is not considered to patentably distinguish the instant claims over the cited prior art.
Allowable Subject Matter
Claims 6, 7, 12, 13 and 24 would be allowable if rewritten to overcome the rejection(s) under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA ), 2nd paragraph, set forth in this Office action and to include all of the limitations of the base claim and any intervening claims.
Claims 17-20 would be allowable if rewritten or amended to overcome the rejection(s) under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA ), 2nd paragraph, set forth in this Office action.
The following is a statement of reasons for the indication of allowable subject matter:
With respect to claims 6 and 17 (and the claims dependent therefrom), the additional features claimed, considered as a whole with the entirety of the process, are considered to distinguish over the prior art. The prior art of record does not disclose or suggest the claimed configuration wherein the distillation column comprises a divided wall column (DWC) and a first lower stream rich in p-xylene is obtained from a first side of the DWC and a second lower stream lean in p-xylene is obtained from a second side of the DWC and wherein the one or more isomerized recycle streams are obtained as at least a portion of the first lower stream.
The office notes that DWCs have been used in the context of p-xylene recovery. See, e.g., Dreux, cited above (see Fig. 2), and Bender et al (US 2016/0272558).
Bender discloses sending a raffinate stream from PX recovery unit to a DWC 130 where it is separated into an EB rich stream 132 and an EB depleted stream 134 (both overhead streams). The EB-depleted stream is then fed to isomerization unit 140 and the EB-rich stream is fed to isomerization unit 150 (see Fig. 2; [0018]).
The instant claims, however, require sending the raffinate stream to liquid phase isomerization, then feeding isomerized raffinate to a DWC, and obtaining a first lower stream rich in p-xylene from a first side of the DWC and a second lower stream lean in p-xylene from a second side of the DWC. In other words, the claimed flow configuration is distinguished from the prior art references and there do not appear to be any teachings and/or suggestions which would lead a person of ordinary skill in the art to modify the prior art in such a way as to arrive at the instant claimed embodiment.
With respect to claims 12 and 24 (and the claims dependent therefrom), the additional features claimed, considered as a whole with the entirety of the process, are considered to distinguish over the prior art. The prior art of record does not disclose or suggest carrying out liquid-phase isomerization on an intermediate stream obtained from the p-xylene recovery unit, where the intermediate stream comprises p-xylene at a concentration higher than in the raffinate stream and lower than in the product stream, and recycling the obtained isomerate to the p-xylene recovery unit.
Both Salciccioli and Dreux disclose obtaining an intermediate stream from the p-xylene recovery unit. In Salciccioli, an intermediate stream 124 comprising ethylbenzene is sent to a downstream PX recovery unit and not an isomerization reactor (see Fig. 1; [0024]-[0025]). In Dreux, an intermediate stream comprising ethylbenzene is sent to gas-phase isomerization (see Fig. 1). The prior art does not provide adequate teachings and/or suggestions to modify the prior art references in such a way as to arrive at the instant claimed embodiment.
Conclusion
Any inquiry concerning this communication or earlier communications from the examiner should be directed to RENEE ROBINSON whose telephone number is (571)270-7371. The examiner can normally be reached Monday - Thursday 8:00a-5:00p and Friday 8:00a-2:00p.
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/Renee Robinson/Primary Examiner, Art Unit 1772
