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 .
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 1-9 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 claim 1, in line 2, line 8, line 9 and line 11 the phrase "preferably" renders the claim indefinite because it is unclear whether the limitations following the phrase are part of the claimed invention. See MPEP § 2173.05(d).
Regarding claim 2, line 2 the phrase "preferably" renders the claim indefinite because it is unclear whether the limitations following the phrase are part of the claimed invention. See MPEP § 2173.05(d).
Regarding claim 9, line 3 the phrase "preferably" renders the claim indefinite because it is unclear whether the limitations following the phrase are part of the claimed invention. See MPEP § 2173.05(d).
A broad range or limitation together with a narrow range or limitation that falls within the broad range or limitation (in the same claim) may be considered indefinite if the resulting claim does not clearly set forth the metes and bounds of the patent protection desired. See MPEP § 2173.05(c). In the present instance, claim 3, line 3 recites the broad recitation 0.001 and 0.5, and the claim also recites 0.005 and 0.1 which is the narrower statement of the range/limitation. claim 4, line 3 and line 4 recites the broad recitation 0 0C and 80 0C, and the claim also recites 20 0C and 70 0C which is the narrower statement of the range/limitation. Claim 5, line 3 recites the broad recitation 4 and 60 bar, and the claim also recites 10 and 50 bar which is the narrower statement of the range/limitation. Claim 7, line 3 and 4 recites the broad recitation 0.1% and 20%, and the claim also recites 1% and 5% which is the narrower statement of the range/limitation. The claim(s) are considered indefinite because there is a question or doubt as to whether the feature introduced by such narrower language is (a) merely exemplary of the remainder of the claim, and therefore not required, or (b) a required feature of the claims.
Regarding claim 4, line 3 the phrase "for example" renders the claim indefinite because it is unclear whether the limitation(s) following the phrase are part of the claimed invention. See MPEP § 2173.05(d).
Regarding claim 8, line 3, the phrase "such as" renders the claim indefinite because it is unclear whether the limitations following the phrase are part of the claimed invention. See MPEP § 2173.05(d).
Claim Rejections - 35 USC § 103
In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis (i.e., changing from AIA to pre-AIA ) for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status.
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
The factual inquiries for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows:
1. Determining the scope and contents of the prior art.
2. Ascertaining the differences between the prior art and the claims at issue.
3. Resolving the level of ordinary skill in the pertinent art.
4. Considering objective evidence present in the application indicating obviousness or nonobviousness.
Claims 1-9 are rejected under 35 U.S.C. 103 as being unpatentable over Willi et al (DE 19654516 C1 machine translation published October 10, 1998)).
Applicants’ claimed invention is directed to a process for producing methyl mercaptan, comprising the following steps: A) methanol is reacted with hydrogen sulfide to form a stream (M), preferably in gaseous form, comprising methyl mercaptan, unreacted H2S and possibly sulfur byproducts; B) optionally, said stream (M) is condensed; C) at least one step of purification of said stream (M) is performed to obtain a stream enriched in methyl mercaptan; D) the gaseous vents resulting from said at least one purification step are recovered, said gaseous vents comprising at least one sulfur compound, preferably H2S; E) a gas-liquid extraction of said at least one sulfur compound, preferably H2S, is performed with liquid methanol so as to obtain a liquid methanol enriched in sulfur compound(s),preferably in H2S; and F) optionally, said enriched methanol is used as reagent for the reaction of step A).
Willi teaches a process for the separation of the product gas mixture of the catalytic synthesis of methyl mercaptan from hydrogen sulfide and methanol into the components methyl mercaptan, dimethyl sulfide, polysulfide, water, methanol, hydrogen sulfide and at a temperature of 100 to 150 ° C and a pressure of 6 to 12 bar Inert gas containing the following process steps: a) Separation of the product gas stream into an aqueous condensate containing methanol and water and an organic condensate containing hydrogen sulphide, methyl mercaptan and dimethyl sulphide and a residual gas stream containing hydrogen sulphide and methyl mercaptan by two-stage partial condensation, the aqueous condensate at temperatures between 55 and 65 ° C and the organic condensate is condensed at temperatures between 15 and 30 ° C, b) Absorption of methyl mercaptan and dimethyl sulfide from the residual gas stream in a first wash with methanol and splitting the washed, hydrogen-rich gas stream into a circulating gas stream and a discharge stream in a volume ratio of 5: 1 to 20: 1, c) absorption of hydrogen sulfide from the discharge stream in a second wash with methanol and removal of the cleaned discharge stream from the process sequence, with fresh methanol being used for the second wash, which is used as a detergent for the first wash after loading with hydrogen sulfide, d) Distilling the loaded washing methanol and the aqueous and organic condensate to separate hydrogen sulfide as a gaseous top product from the remaining components of the product gas mixture, which arise as a liquid crude product in the distillation bottom and feed the separated hydrogen sulfide into the circulating gas stream or into the residual gas stream and e) Separating the crude product by means of further distillations into the components methyl mercaptan, dimethyl sulfide, dimethyl ether, polysulfides, methanol and water. See claim 1.
While both the claimed invention and Willi use methanol for gas-liquid extraction of sulfur compounds, a key difference in the claimed invention lies in the specific point of integration back into the overall process flow and the nature of the stream being treated.
Willi uses a two-stage methanol wash to clean a residual gas stream that still contains valuable product components (methyl mercaptan and dimethyl sulfide), followed by a distillation step that yields gaseous H2S which is recycled.
A person of ordinary skill in the art (PHOSITA) of chemical engineering or methyl mercaptan production, reviewing the cited prior art, would recognize that the process described in the prior art already teaches using liquid methanol for gas-liquid extraction (absorption) to capture sulfur compounds (H2S, methyl mercaptan, dimethyl sulfide)
From process gas streams. A PHOSITA, prior to the effective filing date of the claimed invention would find it an obvious design choice or a matter of routine optimization to streamline a known recycling process. Since methanol is already a primary reagent in the synthesis (Step A of the invention, and inherent in the prior art process), using a methanol solution already charged with H2S directly as a reagent feed (Step F) is a logical and efficient process intensification technique. This modification avoids the capital expenditure and energy consumption associated with the distillation column used in the prior art (Step d). The PHOSITA would have a reasonable expectation of success in making this integration, as the raw materials required for the reaction (methanol and H2S) are present in the recycled stream in a readily usable liquid form.
Regarding claim 2, Willi (Step a) explicitly teaches a "two-stage partial condensation" that separates the product gas stream into an "aqueous condensate" and an "organic condensate," which inherently involves creating and managing two separate liquid phases. Decantation is a basic mechanical method used to separate immiscible liquids or liquids from settled solids based on density differences. A Person Having Ordinary Skill in the Art (PHOSITA) managing a complex mixture like crude methyl mercaptan (which involves water, methanol, organic sulfides, etc.) would find it standard practice to use phase separation and decantation whenever two immiscible or partially miscible liquid phases naturally form in the process stream to achieve preliminary separation or remove unwanted byproducts. Applying this known technique within a general "purification" step (Step C) is a matter of routine engineering implementation, not an inventive step (see claim 1).
Regarding claim 3, Willi teaches a person having ordinary skill in the art (PHOSITA) how to absorb H2S and methyl mercaptan into methanol (prior art Steps b and c). Willi also provides specific concentration ranges for the resulting H2S-loated methanol stream 15-20 wt% H2S). see page 5, last two lines through page 6 lines 1-9.
A PHOSITA designing or optimizing an absorption column (which is the equipment used for gas-liquid extraction in Step E) routinely adjusts operational parameters like solvent-to-gas ratios to achieve desired separation efficiency and concentration targets. The specific ranges claimed (0.001 to 0.5 mass ratio, which translates roughly to ensuring the resulting liquid stream falls within industrially relevant concentrations like those cited in the prior art) represent typical engineering operational windows.
Selecting an optimal ratio within a known process to achieve an expected result (efficient absorption of a known quantity of sulfur compounds into a known solvent, methanol) is a matter of routine experimentation and basic chemical engineering principles, and does not rise to the level of an inventive step.
Regarding claim 4, Willi teaches operating conditions relevant to the process components:
Aqueous condensate separation occurs between 55°C and 65°C.
Organic condensate separation occurs between 15°C and 30°C.
The reactor exit temperature is 340°C to 360°C, subsequently cooled to 100°C to 150°C for initial condensation. See claim 1 and page 4, 3rd paragraph.
The claimed ranges (0°C to 80°C) generally fall within or adjacent to these known operational temperatures.
Regarding claim 5, Willi explicitly teaches that the overall process operates at a pressure in the range of 6 to 12 bar. The PHOSITA (Person Having Ordinary Skill in the Art) would understand that the various separation and purification steps occur within this general system pressure envelope. See claim 1.
Regarding claim 6, Willi discloses that the loaded methanol stream contains 15-20 wt% H2S depending on the optimal stoichiometry or operating window of the reactor in Step A, the PHOSITA might need to dilute this concentrated stream with fresh methanol to achieve the optimal feed composition. The specific act of blending the two types of methanol (recycled enriched and fresh) does not introduce a new technical effect or principle, but merely describes a standard method of implementing the already obvious recycling loop described in the main claim. See claim 1 and page 5, last two lines through page 6 lines 1-9.
Regarding claim 7, Willi teaches that the loaded washing methanol stream already contains a significant amount of H2S:
PNG
media_image1.png
1
1
media_image1.png
Greyscale
"...washing methanol: 15-20 wt% H2S; aqueous condensate: 1-2 wt%; organic condensate: approx. 20 wt% H2S…”
PNG
media_image1.png
1
1
media_image1.png
Greyscale
The claimed range of "0.1% to 20%" completely encompasses the "1-2 wt%" found in the aqueous condensate stream of Willi, and overlaps substantially with the "15-20 wt%" found in Willi’s main washing methanol stream. The most preferred ranges (1-10 wt% or 1-5 wt%) fall directly within the range boundaries defined by Willi’s process streams. page 5, last two lines through page 6 lines 1-9.
Regarding claim 8, Willi discloses that the product gas mixture (and subsequent streams like the residual gas and condensates) contains every component listed in Claim 8:
PNG
media_image1.png
1
1
media_image1.png
Greyscale
H2S, methyl mercaptan, and dimethyl sulfide are listed as main components of the organic condensate and residual gas stream in Willi’s process.
Methanol and water are listed in the aqueous condensate.
Polysulfides (which includes dimethyl disulfide) are listed as components separated later in the process (Step e).
Inert compounds are inherent components often found in industrial synthesis loops (e.g., nitrogen, unreacted hydrogen if it's the source for H2S, etc.). The Willi mentions "Inert gas" in its preamble. See claim 1.
A Person Having Ordinary Skill in the Art (PHOSITA) managing this specific chemical process would expect all these components to be present in various equilibrium states throughout the system, including in the final "gaseous vents" that result from purification steps.
Regarding claim 9, Willi (Steps b and c) explicitly describes "washing with methanol," which is the functional definition of an absorption process typically executed in an absorption column (also known as a packed or tray column) in an industrial setting. This equipment is the default apparatus for continuous gas-liquid contact operations. See claim 1.
PNG
media_image1.png
1
1
media_image1.png
Greyscale
Any inquiry concerning this communication or earlier communications from the examiner should be directed to JAFAR F PARSA whose telephone number is (571)272-0643. The examiner can normally be reached M-F 10:00 AM-6:30PM.
Examiner interviews are available via telephone, in-person, and video conferencing using a USPTO supplied web-based collaboration tool. To schedule an interview, applicant is encouraged to use the USPTO Automated Interview Request (AIR) at http://www.uspto.gov/interviewpractice.
If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Scarlett Goon can be reached at 571-270-5241. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
Information regarding the status of published or unpublished applications may be obtained from Patent Center. Unpublished application information in Patent Center is available to registered users. To file and manage patent submissions in Patent Center, visit: https://patentcenter.uspto.gov. Visit https://www.uspto.gov/patents/apply/patent-center for more information about Patent Center and https://www.uspto.gov/patents/docx for information about filing in DOCX format. For additional questions, contact the Electronic Business Center (EBC) at 866-217-9197 (toll-free). If you would like assistance from a USPTO Customer Service Representative, call 800-786-9199 (IN USA OR CANADA) or 571-272-1000.
/JAFAR F PARSA/Primary Examiner, Art Unit 1692