DETAILED ACTION
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Claim Status
Claims 1-9, 11, 13-18, and 20 are amended. Claims 18-20 are withdrawn due to an earlier restriction requirement.
The amendments overcome the previous claim objections and 112(b) rejections.
Claims 1-17 are pending for examination below.
Response to Arguments
Applicant’s arguments and amendments filed 24 December 2025 with respect to the rejection(s) of claim(s) 1-17 under USC 013 over Drobyshev have been fully considered and are persuasive. Drobyshev in view of Song does not teach the claimed process comprising adiabatic reaction of the reactants over the amended catalyst comprising tantalum, niobium, hafnium, or tin, because Song is directed to a different catalyst and thus it is not necessarily obvious to use the adiabatic operation of Song. The secondary reference Huppke does not teach increasing the oxygen content to more than 3 vol% during the first combustion step. Therefore, the rejections have been withdrawn. However, upon further consideration, a new ground(s) of rejection is made in view of newly discovered prior art in view of the amendments.
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.
Claims 1-8 and 11-17 are rejected under 35 U.S.C. 103 as being unpatentable over Drobyshev et al. (WO 2020/126920) in view of Lund (A First Course on Kinetics and Reaction Engineering) and Huang et al. (US 2022/0183403).
US 2022/0048833 is used as the English language version of WO 2020/126920 herein, and all citations are directed thereto.
With regard to claims 1, 2, and 11, Drobyshev teaches a method for producing butadiene from ethanol (paragraph [0001]) comprising the following steps:
a) reacting a mixture of ethanol and acetaldehyde in a reaction zone comprising n fixed bed reactors comprising a catalyst which is preferably tantalum, where n is 4 or a multiple thereof, to produce 1,3-butadiene (paragraphs [0035]). Drobyshev further teaches that the catalyst is a supported catalyst comprising tantalum (instant claims 1 and 2) (paragraph [0053]).
b) regenerating the catalyst in a regeneration step comprising the following phases (paragraph [0036]):
i) a stripping phase comprising a temperature of 300-400°C and contacting the supported catalyst with a flow of inert gas (paragraph [0037]). This is identical to the range of 300-400°C of step b)i. of instant claim 1. Drobyshev only teaches the presence of inert gas in the stripping phase i), where the inert gas can be only nitrogen. Therefore, because Drobyshev teaches a similar stripping step b)i. at the same temperature and comprising the same inert gas, and further because Drobyshev is silent regarding any oxygen content in the inert gas stream for stripping step b)i., one of ordinary skill in the art would reasonably conclude that the inert gas stream of Drobyshev comprises no oxygen, which is within the range of 200 vppm or less oxygen as claimed.
ii) a first combustion phase comprising a temperature of 300-450°C and contacting with a stream having inert gas and an oxygen content of 0.3 to 0.7 vol% (paragraph [0038]). The temperature overlaps the range of 350-400°C of step b)ii. of instant claim 1, rendering the range prima facie obvious. The amount of 0.3 to 7 vol% is within the ranges of 0.2 to 8 vol% of step b)ii. instant claim 1 and less than 1 vol% of instant claim 11.
iii) a second combustion phase comprising a temperature of 390-550°C and contacting with a stream having inert gas and an oxygen content of 4 to 8 vol% (paragraph [0039]). This overlaps the range of 400-550°C, rendering the range prima facie obvious, and is within the range of 0.2 to 8 vol% of step b)iii. of instant claim 1.
iv) a stripping step having a temperature of 550-300°C and contacting with a flow of inert gas (paragraph [0040]). This is identical to the range of 550-300°C of step b)iv. of instant claim 1. Drobyshev only teaches the presence of inert gas in the stripping phase iv), where the inert gas can be only nitrogen (paragraph [0040]). Therefore, because Drobyshev teaches a similar stripping step b)iv. at the same temperature and comprising the same inert gas, and further because Drobyshev is silent regarding any oxygen content in the inert gas stream for stripping step b)iv., one of ordinary skill in the art would reasonably conclude that the inert gas stream of Drobyshev comprises no oxygen, which is within the range of 200 vppm or less oxygen as claimed.
Drobyshev also teaches that the gas flows to the regeneration steps L1, L2, and L3 are heated in a heater F1 before passing to the reactor R1 when it is in the regeneration phase (paragraph [0075] and Figure 2).
Drobyshev fails to teach i) that the reactors for step a) are adiabatic reactors, ii) that the first combustion step comprises an increase in oxygen content to at least 3 vol%, or iii) that the regeneration is adiabatic.
With regard to i), Drobyshev is silent on whether the reactors are adiabatic or isothermal reactors.
Lund teaches that there is a spectrum of modes of reactor operations ranging from isothermal to adiabatic, where the space between includes reactors that are neither adiabatic nor isothermal (page 6, first paragraph). Lund then teaches that it takes a lot of effort in most cases to make an industrial reactor run isothermally, and that an adiabatic reactor represents a limiting case of the temperature variations (page 9, last full paragraph). Lund additionally teaches running an endothermic reaction in an adiabatic reactor is known (page 6, third bullet point) and that one of ordinary skill in the art is able to use the known information about kinetics of endothermic reactions to design a suitable reactor system for a reaction (page 17, last full paragraph).
Therefore, performing the reaction of Drobyshev in adiabatic is a selection of a known way of performing endothermic reactions which Lund teaches has a reasonable expectation of success and would not require undue experimentation, because one of ordinary skill in the art knows how to run an endothermic reaction adiabatically (page 6, third bullet point and page 17, last full paragraph).
With regard to ii), Huang teaches a process for regenerating a catalyst by oxygen treatment (Abstract). Huang teaches that the purpose of the oxygen treatment is to remove residual hydrocarbons and/or carbon rich deposits (coke) from the catalyst (paragraph [0035]). Huang also teaches that there are three main methodologies to use the proper combination of O2 flow and temperature to minimize unwanted temperature exotherms and minimize the amount of coke on the treated catalyst, (A) Fixed O2 levels with increased temperature; (B) Fixed temperature with increased O2; and (C) Combination of (A) and (B) (paragraph [0038]). Huang further teaches that (C) involves treating the catalyst at a fixed temperature with an increase in O2 to a specific level, followed by ramping to a higher temperature and then increasing the O2 again (paragraph [0043]). Huang additionally teaches that the O2 is increased from a very low level (less than 1 vol%) to a maximum value (up to 40 vol%) (paragraph [0041]), where up to 40 vol% overlaps the range of at least 3 vol% of instant claim 1 and the range of 3-6 vol% of instant claim 11, rendering the ranges prima facie obvious. Huang also teaches that the approach (C) allows for controlled conditions which minimize exotherms and unwanted temperature excursions (paragraph [0044]).
While Huang does not specifically teach that the described regeneration process is suitable for the catalyst of Drobyshev, Huang generally teaches that the oxygen containing step is suitable for the same purpose as the combustion step of Drobyshev, which is to remove coke from a solid catalyst, and Huang also teaches that the regeneration provides the benefits of minimizing exotherms and unwanted temperature excursions (paragraph [0044], which would be expected to be applicable to all regeneration processes.
Therefore, it would have been obvious to one of ordinary skill in the art at the time of the invention to add the step of increasing the oxygen content in the first combustion step from less than 1 vol% to at least 3 vol%, as claimed, because each of Drobyshev and Huang teach regeneration of catalysts in an oxygen environment to remove coke where the oxygen starts at an amount of less than 1 vol% and increases to an amount of greater than 2 vol% and Huang teaches that increasing the oxygen content during the first combustion phase before increasing it again after a temperature increase as in mode (C) allows for controlled conditions which minimize exotherms and unwanted temperature excursions (paragraph [0044]).
With regard to iii), Drobyshev in view of Huang teaches the same regeneration steps for the same catalyst and using similar conditions, where each feed to each regeneration step is preheated in heater F1, as described above. Therefore, one of ordinary skill in the art would expect that the regeneration of Drobyshev in view of Huang is also adiabatic regeneration, as claimed, absent any evidence to the contrary.
With regard to claim 3, Drobyshev teaches the n reactors, where n is 4 or a multiple of 4, and where the reactors function in parallel (paragraph [0057]). Thus, Drobyshev teaches the first and second adiabatic reaction zones each comprising a catalyst and producing 1,3-butadiene, as claimed.
With regard to claim 4, Drobyshev teaches that each of the reactors for conversion of ethanol/acetaldehyde to butadiene are also fed with a supply of acetaldehyde (paragraph [0056]) and that the reactors are functioning in sequence (paragraph [0057]). Thus, Drobyshev teaches feeding acetaldehyde to the reactor after the first adiabatic reactor comprising the catalyst for producing butadiene, as claimed.
With regard to claim 5, Drobyshev teaches that the additional feed also comprises ethanol, such that the mole ratio of ethanol to acetaldehyde is 1 to 5 (paragraph [0056]), which is within the range of 0.1 to 5 of instant claim 5.
With regard to claim 6, Drobyshev teaches that there are n reactors, where n is 4 or a multiple of 4, and the reactors are functioning in sequence (paragraph [0057]). Thus, Drobyshev teaches at least a first and second reactor connected in series, where at least part of the effluent from the first reactor is fed to the second reactor.
With regard to claim 7, Drobyshev teaches that the regeneration stage is carried out for a total time equal to half the catalytic cycle time (time period for which the butadiene reaction is carried out) (paragraph [0036]) which is within the range of 1/6 to ½ of instant claim 7.
With regard to claim 8, Drobyshev teaches that the catalytic cycle time is 1 to 20 days (paragraph [0053]). As such, the regeneration stage is carried out for 12 to 240 hours, which overlaps the range of less than 80 hours of instant claim 8, rendering the range prima facie obvious.
With regard to claim 12, Drobyshev does not specifically teach the combustion iii is carried out until there is no local temperature maximum in the reactor. However, one of ordinary skill in the art would understand that a local temperature maximum indicates that there is catalyst still containing coke. Thus, the absence of the local temperature maximum indicates the absence of coke on the catalyst, and that the combustion reaction is substantially complete.
Therefore, it would have been obvious to one of ordinary skill in the art at the time of the invention to carry out combustion step iii until there is no local temperature maximum, as one of ordinary skill in the art is aware this is an indication the combustion is substantially complete, and stopping the combustion when it is complete saves energy and oxygen gas,
With regard to claim 13, Drobyshev teaches the method above, where the stripping step i. takes place at a temperature of 300-400°C (paragraph [0075]). The instant specification recites that the temperature of the gas during the stripping falls about 50°C due to the endothermic nature of the step (page 14, line 30 to page 15, line 2). Thus the temperature of the gas is expected to be less than 400°C, as claimed.
With regard to claim 14, Drobyshev teaches the method above, where the combustion step ii. takes place at a temperature of 300-450°C (paragraph [0038]). Drobyshev does not explicitly teach that the heated gas flow at the end of the combustion step ii. contacts the catalyst at a temperature of 400°C or less. However, because Drobyshev teaches a maximum temperature of the combustion step is 450°C, one of ordinary skill in the art would reasonably expect the temperature of the oxygen stream to be less than 450°C at the end of the combustion step ii., which overlaps the range of 400°C or less of instant claim 14, rendering the range prima facie obvious.
With regard to claim 15, Drobyshev teaches the method above, where the combustion step iii. takes place at a temperature of 390-550°C (paragraph [0039]). Drobyshev does not explicitly teach that the heated gas flow at the end of the combustion step iii. contacts the catalyst at a temperature of 550°C or less. However, because Drobyshev teaches a maximum temperature of the combustion step is 550°C, one of ordinary skill in the art would reasonably expect the temperature of the oxygen stream to be less than 550°C at the end of the combustion step iii., which is identical to the claimed range of less than 550°C.
With regard to claim 16, Drobyshev teaches the method above, where the stripping step iv. decreases to a temperature of 300-370°C at the end (paragraph [0067]). This is within the range of 450°C or less of instant claim 16.
With regard to claim 17, Drobyshev teaches the process above (instant claim 17 step y). Drobyshev further teaches that the reaction process also comprises a step of converting ethanol into an ethanol/acetaldehyde mixture over a catalyst (Ca) which is on a matrix (support) (instant claim 17 step x) (paragraph [0046]).
Claims 9 and 10 are rejected under 35 U.S.C. 103 as being unpatentable over Drobyshev et al. (WO 2020/126920) in view of Lund (A First Course on Kinetics and Reaction Engineering) and Huang et al. (US 2022/0183403) as applied to claim 1 above, and further in view of Heckelsberg (US 3,586,731).
With regard to claim 9, Drobyshev teaches regeneration comprising the stripping step i. with a stream comprising an inert gas (paragraph [0037]).
Drobyshev does not teach that steam can be used as the inert gas in the stripping step i.
Heckelsberg teaches a reaction comprising a tantalum catalyst on a support to produce olefins (Abstract). Heckelsberg further teaches that during regeneration, steam can be added to control the regeneration temperature during the regeneration which comprises flushing with an inert gas and then contacting with an oxygen gas for combustion (column 5, lines 1-11). While Heckelsberg does not teach the same reaction as Drobyshev, Heckelsberg teaches a similar catalyst comprising tantalum on a support and a similar regeneration with inert gas and combustion steps. Thus, one of ordinary skill in the art would reasonably conclude that the regeneration of Heckelsberg is related art to the regeneration of Drobyshev.
Therefore, it would have been obvious to one of ordinary skill in the art at the time of the invention to add steam to the stripping step as taught by Heckelsberg, because Drobyshev and Heckelsberg each teach regeneration of a tantalum catalyst on a support with inert gas and oxygen containing gas, and Heckelsberg teaches that adding the steam allows for controlling the regeneration temperature (column 5, lines 10-11).
With regard to claim 10, Drobyshev teaches regeneration comprising the combustion step ii. with a stream comprising an inert gas and oxygen (paragraph [0038]).
Drobyshev does not teach that steam can be used in the combustion step ii.
Heckelsberg teaches a reaction comprising a tantalum catalyst on a support to produce olefins (Abstract). Heckelsberg further teaches that during regeneration, steam can be added to control the regeneration temperature during the regeneration which comprises flushing with an inert gas and then contacting with an oxygen gas for combustion (column 5, lines 1-11). While Heckelsberg does not teach the same reaction as Drobyshev, Heckelsberg teaches a similar catalyst comprising tantalum on a support and a similar regeneration with inert gas and combustion steps. Thus, one of ordinary skill in the art would reasonably conclude that the regeneration of Heckelsberg is related art to the regeneration of Drobyshev.
Therefore, it would have been obvious to one of ordinary skill in the art at the time of the invention to add steam to the combustion step ii. as taught by Heckelsberg, because Drobyshev and Heckelsberg each teach regeneration of a tantalum catalyst on a support with inert gas and oxygen containing gas, and Heckelsberg teaches that adding the steam allows for controlling the regeneration temperature (column 5, lines 10-11).
Drobyshev in view of Heckelsberg does not specifically teach that the amount of steam added may be decreased during the combustion step ii such that the end of the combustion step ii contains no steam. However, because Drobyshev in view of Heckelsberg teaches that the steam is for the purpose of controlling the regeneration temperature, the addition rate of steam is a result-effective variable, and can be optimized. Therefore, it would have been obvious to one having ordinary skill in the art to have determined the optimum rate decreasing the steam such that there is no steam at the end of combustion step ii. as claimed, because it has been held that discovering an optimum value of a result effective variable involves only routine skill in the art. See MPEP 2144.05(II).
Conclusion
Applicant's amendment necessitated the new ground(s) of rejection presented in this Office action. Accordingly, THIS ACTION IS MADE FINAL. See MPEP § 706.07(a). Applicant is reminded of the extension of time policy as set forth in 37 CFR 1.136(a).
A shortened statutory period for reply to this final action is set to expire THREE MONTHS from the mailing date of this action. In the event a first reply is filed within TWO MONTHS of the mailing date of this final action and the advisory action is not mailed until after the end of the THREE-MONTH shortened statutory period, then the shortened statutory period will expire on the date the advisory action is mailed, and any nonprovisional extension fee (37 CFR 1.17(a)) pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event, however, will the statutory period for reply expire later than SIX MONTHS from the mailing date of this final action.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to ALYSSA L CEPLUCH whose telephone number is (571)270-5752. The examiner can normally be reached M-F, 8:30 am-5 pm, EST.
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/Alyssa L Cepluch/Examiner, Art Unit 1772
/IN SUK C BULLOCK/Supervisory Patent Examiner, Art Unit 1772
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