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 .
Response to Amendment
Applicant’s amendment filed on June 5, 2026 has been received and considered. Claims 1-4 are pending.
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.
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 1-4 are rejected under 35 U.S.C. 103 as being unpatentable over Colling et al. (WO 00/17946 A2) in view of Colman (US 6,288,269 A) and Wang et al. (CN 104447315 A).
Regarding claim 1, Colling et al. discloses a fixed-bed multi-tubular reactor for alkenyl acetate production— namely, vinyl acetate production (i.e., a shell-and-tube reactor 10; see FIG. 1-5; see, e.g., page 5, line 1, to page 6, line 21), comprising:
a plurality of reaction tubes (i.e., a plurality of reactor tubes 120 each containing a catalyst for the production of vinyl acetate) which are supplied with a raw material gas (i.e., reactants comprising ethylene, acetic acid, and oxygen) from a top part of the reactor (i.e., the reactants are fed to the top of the reactor 10 and into a head space 140 under pressure; the reactants are then forced to flow through the reactor tubes 120 from the top of each reactor tube to the bottom of each reactor tube; see flow arrows in FIG. 5);
a thermometer protection tube (i.e., a “small diameter tube” that is a thin-walled stainless steel (or other suitable material) tube for containing a thermocouple 150; see page 2, lines 9-13; page 6, lines 11-14) inserted into at least one of the plurality of reaction tubes 120 from a bottom part of the reactor (i.e., the small diameter tube is positioned in the center of a selected reactor tube 120; as shown in FIG. 5, the small diameter tube is inserted into the reactor tube 120 from a lower part of the reactor 10); and
a thermometer (i.e., a thermocouple 150, such as a multi-point thermocouple; see page 6, lines 6-17) which is inserted in the thermometer protection tube (i.e., the thermocouple is positioned within the small diameter tube).
Colling et al. fails to disclose that the fixed-bed multi-tubular reactor 10 is further configured to supply the reaction tubes 120 with “a mist of an aqueous solution of an alkali metal acetate” from the top part of the reactor.
Colman et al. discloses a fixed-bed reactor for alkenyl acetate production— namely, vinyl acetate production (i.e., a fixed bed reactor 12; see FIG. 1; column 3, line 57, to column 4, line 38), wherein the reactor 12 contains a catalyst bed 13 comprising a catalyst for the production of vinyl acetate. Colman et al. discloses that the catalyst bed 13 is supplied with a raw material gas (i.e., reactants comprising ethylene, acetic acid, and oxygen, supplied by a pipe 14 into a reactor head-space 26 for distribution over catalyst bed 13), and, additionally, a mist of an aqueous solution of an alkali metal acetate (i.e., a potassium acetate solution as a catalyst promoter; the solution being introduced into the pipe 14 as liquid droplets generated by a spray nozzle 16, wherein the liquid droplets evaporate while in the pipe 14 and are carried by the flow of the reactants into the reactor head-space 26 for distribution over the catalyst bed 13; see column 1, lines 28-31; column 4, lines 18-38).
It would have been obvious for one of ordinary skill in the art before the effective filing date of the claimed invention to configure the fixed-bed multi-tubular reactor 10 of Colling et al. to further supply the reaction tubes 120 with a mist of an aqueous solution of an alkali metal acetate from the top part of the reactor because the activity of the catalyst contained in the reaction tubes could be enhanced by the addition of the alkali metal acetate (for instance, potassium acetate), which acts as a catalyst promoter during the production of vinyl acetate, as taught by Colman et al. (see column 1, lines 10-13).
With respect to the newly added limitation, Colling et al. discloses that the fixed-bed multi-tubular reactor 10 is used for the production of vinyl acetate, in which the raw material gas comprises ethylene, acetic acid, and oxygen (see page 5, lines 14-15). Colling et al. does not disclose that the fixed-bed multi-tubular reactor 10 is used for the production of other alkenyl acetates, such as allyl acetate, in which the raw material gas comprises propylene, acetic acid, and oxygen. However, Colling et al. (at page 5, lines 2-3) discloses, “Although the present invention will be described relative to production of VA, it is understood to be generally applicable to reactions involving use of shell and tube reactors.” (with emphasis).
Wang et al. (see FIG. 1; translation) additionally discloses a fixed-bed multi-tubular reactor for alkenyl acetate production— namely, allyl acetate production, comprising: a plurality of reaction tubes (i.e., reaction tubes 2a, 2b, 2c within a reactor cylinder body 1, each reaction tube containing a fixed bed of catalyst for the production of ally acetate; e.g., a Pd-containing catalyst promoted by potassium acetate (KAC), see paragraph [0012]); wherein the reaction tubes are supplied with a raw material gas comprising propylene, acetic acid, and oxygen from a top part of the reactor (i.e., via a raw material feeding port 11).
Wang et al. discloses that fixed-bed multi-tubular reactors used for the production of vinyl acetate can also be used for the production of ally acetate (i.e., “In the production of allyl acetate, we used fixed bed reactor for synthesizing vinyl acetate fixed bed tubular reactor,” see paragraph [0002]). Wang et al. (see paragraphs [0003]-[0004]) also discloses,
“Propylene gas phase method for producing allyl acetate is exothermic reaction, the reaction heat released timely, it can provide a better reaction condition, so as to achieve high selectivity and yield. And a tubular fixed bed reactor has convenient operation, small catalyst mechanical abrasion in the reaction tube, removing speed is fast and so on, especially suitable for propylene gas phase method of producing allyl acetate acetic reaction system.
In recent years, with the continuous enlargement of the allyl acetate production scale reactor the diameter continuously increases, the key problem of uniformly and rapidly removing problem becomes engineering development. This, in turn, is uniformly distributing problem of the fluid in the reactor. Utilization efficiency if fluid cannot be uniformly distributed, the heat cannot be timely removed, forming runaway, caused by too high local temperature, not only affect the catalyst and reactor, the selectivity and yield of the target product, and may cause the damage of the reactor and finally affects the safe device operation.”
Thus, Wang et al. further recognizes the importance of managing the reaction heat during the production of allyl acetate in order to achieve high selectivity and yield and to also prevent thermal runaway caused by the formation of hot spots in the reactor.
It would have been obvious for one of ordinary skill in the art before the effective filing date of the claimed invention to alternatively employ the modified fixed-bed multi-tubular reactor of Colling et al. for the production of allyl acetate, by supplying a raw material gas comprising propylene, acetic acid, and oxygen to the reactor, because fixed-bed multi-tubular reactors were conventionally employed for the production of alkenyl acetates such as vinyl acetate and allyl acetate, as taught by Wang et al., and the processing advantages attained by using the modified reactor of Colling et al., including improvements in temperature control and prevention of thermal runaway, would have also been considered advantageous in the production of allyl acetate by one of ordinary skill in the art.
Regarding claim 2, Colman et al. further discloses that the alkali metal acetate is potassium acetate (see column 1, lines 10-13; column 4, lines 18-22).
Regarding claim 3, Colling et al. (at page 2, lines 3-8; with emphasis added) discloses,
“Within a vinyl acetate reactor there may be as many as 6,000 or more reaction tubes containing catalyst. In a small percentage of those tubes, thermocouples may be placed to detect, determine and monitor temperatures within each of the selected reaction tubes. Shell and tube reactors vary in size and tubes may exceed 20 feet in length. Accordingly, multiple thermocouples, called multi-point thermocouples, may be placed in a given tube so that thermocouples are positioned inside the selected tube over its entire length.”
Colling et al. (at page 8, lines 1-5; with emphasis added) further discloses,
“As can be seen in Figure 2, there may be a large number of reactor tubes 120 within a shell and tube reactor 10. Indeed, the number of reactor tubes 120 within a shell and tube reactor 10 may exceed 6,000. With so many reactor tubes 120 within a shell and tube reactor 10, operators of such vapor-phase processes as a vinyl acetate production process will seek to determine the temperature of reaction within selected reactor tubes 120.”
For instance, Colling et al. (see EXAMPLES, beginning on page 9) discloses a fixed-bed multi-tubular reactor where the temperature of the reaction tubes was monitored during the production of vinyl acetate. Specifically, Colling et al. (at page 9, line 10) discloses, “Eight tubes with thermocouples were monitored over the course of about 90 days.”
Thus, Colling et al. discloses that the number of the reaction tubes 120 having the thermometer protection tube inserted therein can be between 3 to 10 (i.e., eight).
Additionally, the specific number of the reaction tubes 120 having the thermometer protection tube inserted therein is not considered to confer patentability to the claim since the precise number of reaction tubes would have been considered a result effective variable by one of ordinary skill in the art. Therefore, it would have been obvious for one of ordinary skill in the art before the effective filing date of the claimed invention to select a suitable number of the reaction tubes (i.e., as a “small percentage” of the total number of reactor tubes) to have the thermometer protection tube inserted therein in the modified reactor of Colling et al., based on the size of the reactor and the number of reaction tubes in the reactor, in order to satisfactorily evaluate the reactor for signs of thermal runaway during the production of vinyl acetate (see Colling et al., at page 3, lines 21-30).
Regarding claim 4, Colling et al. discloses that the thermometer is a thermocouple (i.e., a thermocouple 150, such as a multi-point thermocouple; see page 6, lines 6-11).
Response to Arguments
Applicant's arguments filed on June 5, 2026 have been fully considered, but they are not found persuasive. Applicant (at page 4, second paragraph) argues,
“It is submitted that neither Colling nor Colman recognizes the problem unique to the present invention that in the production of allyl acetate, the mist of an aqueous solution of an alkali metal acetate attaches to, or flows down along, the thermometer protection tube, causing the thermometer to lose its representativeness. As such, neither Colling nor Colman teaches or suggests the technical solution achieved by the present invention.” (with emphasis).
The Office respectively disagrees. The fact that the inventor has recognized another advantage which would flow naturally from following the suggestion of the prior art cannot be the basis for patentability when the differences would otherwise be obvious. See Ex parte Obiaya, 227 USPQ 58, 60 (Bd. Pat. App. & Inter. 1985).
Applicant (at page 4, third and fourth paragraphs) further argues,
“In addition, it is submitted that Colling's operational principle is incompatible with Colman.
Colling intentionally restricts the flow of reactants through selected reaction tubes containing thermocouples in order to make these selected reaction tubes hotter than other tubes, thereby enabling the early detection of signs of thermal runaway. Colling explains that these restricted-flow thermocouple tubes are more susceptible to changes in reaction conditions and aging of the catalyst, and tend to register hotter than the remainder of the reaction tubes, which serves as a warning of the potential for thermal runaway (see "SUMMARY OF INVENTION," etc.). To achieve this, Colling provides a "flow restricting insert 160" with a narrow "channel 170" at the inlet of the reaction tube containing the thermocouple (FIG. 5).
If liquid droplets of a solution of potassium acetate as taught by Colman were introduced into Colling's reactor from above, there is a high risk that the potassium acetate salt (formed upon evaporation of water) or the liquid droplets themselves would deposit or adhere within the narrow channel 170 of Colling's insert 160. This would completely clog the flow path. If the flow path is clogged, it becomes impossible to distinguish whether a temperature rise is a sign of thermal runaway or a result of the clogging of the flow path. Thus, combining Colman with Colling would defeat Colling's original purpose of detecting thermal runaway. Therefore, one of ordinary skill in the art would not have attempted such modification of Colling since it would destroy the principle of operation of Colling or be contrary to Colling's objectives.” (with emphasis).
The Office respectfully disagrees.
Firstly, applicant has not presented any evidence showing the teachings to be incompatible. Arguments presented by applicant cannot take the place of evidence in the record, where evidence is necessary. See MPEP §2145, I.
Secondly, Colman et al. (see column 2, line 64, to column 3, line 6) discloses,
“… The promoter may evaporate on entering the pipe and is carried by the flow of reactants into the reactor for deposition over the catalyst bed. It has been found that fluid deposits more evenly over the catalyst bed as a vapour rather than a liquid. Thus, in a preferred embodiment, the distance between the nozzle and catalyst bed is adjusted to maximise the residence time of the nozzle fluid in the inlet. This ensures that the a relatively large proportion of the nozzle fluid is evaporated before entering the reactor.” (with emphasis added).
Therefore, it would have been obvious for one of ordinary skill in the art before the effective filing date of the claimed invention to adjust the distance between the nozzle which produces the mist of the aqueous solution of alkali metal acetate (potassium acetate) and the catalyst bed in the fixed-bed multi-tubular reactor of Colling et al. in order to maximize the residence time of the solution in the inlet of the reactor and thereby ensure that the solution was fully evaporated before entering the catalyst bed, given that the fluids will deposit more evenly over the catalyst bed as a vapor rather than a liquid, as taught by Colman et al. Thus, by following the suggestions of the prior art, the clogging of the flow path due to the presence of “liquid droplets of the aqueous solution of alkali metal acetate” at the inlet of the reaction tube would not have been expected by one of ordinary skill in the art.
Thirdly, Colling et al. discloses that the restricted flow through the reaction tube can be achieved in a variety of ways. For instance, while a flow restricting insert 160 has been shown at the inlet end of the reaction tube 120 in FIG. 5, the flow restricting insert can alternatively be located at the outlet end of the reaction tube (see page 7, at lines 12-14 and 27-28). The restricted flow through the reaction tube can also be achieved by providing a smaller diameter support material in a portion of the reaction tube (see page 7, at lines 18-26). In addition, the reduction in the reactant flow through the reaction tube merely amounts to about 5% (see ref. claims 20, 23) or about 10-15% (see page 7, lines 5-8). Therefore, for these additional reasons, the Office asserts that the clogging of the flow path at the inlet of the reaction tube in the modified reactor of Colling et al., due to the presence of liquid droplets of the potassium acetate solution, would not have been expected by one of ordinary skill in the art.
Conclusion
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure:
Roscher et al. (US 2014/0194649 A1) is cited to illustrate the state of the art. In particular, Roscher et al. (at paragraph [0002]) discloses,
“Processes for the acetoxylation of ethylene in the gas phase are of particular industrial interest. It is known from the literature that acetoxylations can be carried out industrially by catalytic gas-phase oxidation of olefins such as ethene or propene in fixed-bed reactors. These reactions are preferably carried out in shell-and-tube reactors. Unsaturated esters such as vinyl acetate, inter alia, are prepared by means of this reaction. In general, this reaction is carried out by passing a gaseous mixture comprising molecular oxygen, an olefin and acetic acid through a reactor. Use is usually made of a shell-and-tube reactor in which a plurality of reaction tubes are arranged in parallel and in each of which a uniform catalyst charge is located. The excess heat of reaction involved is removed by means of a heat transfer medium. An example of such a reactor is a boiling water reactor.” (with emphasis added).
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.
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/JENNIFER A LEUNG/Primary Examiner, Art Unit 1774
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