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 .
DETAILED ACTION
1. This application is a 371 of PCT/GB2021/053131 12/01/2021. FOREIGN APPLICATIONS: UNITED KINGDOM 2019393.4 12/09/2020.
Claims 1-7, 9-12, 14-20 are pending.
Response to Amendments and Arguments
2. The rejections of canceled claims are withdrawn. The rejection of claims 1-7, 9-11, 14-20 under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA ), second paragraph, is withdrawn based upon the amendments.
The rejection of claim(s) 1, 3, 5-7, 9-11, 13-14, 16, 19-20 under 35 U.S.C. 103 as being unpatentable over Hale and Kyprianou in view of Luo is maintained, however the rejection of claim 2 is withdrawn. The rejection of claim(s) 4, 15 and 18 under 35 U.S.C. 103 as being unpatentable over Hale and Kyprianou in view of Luo as applied to claims 1, 3, 5-7, 9-11, 13-14, 16, 19-20 above, and further in view of Dunning is maintained. The rejection of claim(s) 15 and 17 under 35 U.S.C. 103 as being unpatentable over Hale and Kyprianou in view of Luo as applied to claims 1, 3, 5-7, 9-11, 13-14, 16, 19-20 above, and further in view of Fischer is maintained.
Applicants’ representative’s arguments submitted July 7, 2026 have been fully considered but are unpersuasive. In response to applicant's arguments against the references individually, one cannot show nonobviousness by attacking references individually where the rejections are based on combinations of references. See In re Keller, 642 F.2d 413, 208 USPQ 871 (CCPA 1981); In re Merck & Co., 800 F.2d 1091, 231 USPQ 375 (Fed. Cir. 1986). According to the arguments, “the claimed ranges are relevant at least because, as discussed on page 6, lines 10-17 of the specification” precipitation is a problem and applicant has discovered concentration ranges that prevent precipitation in the reactor. Process optimization such as changes in temperature, concentration of reagents are routine. Hale shows a clear dependence of the reaction rate on temperature and acid concentration. According to Kyprianou “The influence of key parameters, such as HNO3:DNT molar ratio, residence time, and process temperature were investigated and optimized by applying a design-of-experiments approach.” However as discussed in MPEP 2144.05 III A. “Applicants can rebut a prima facie case of obviousness by showing the criticality of the range. “The law is replete with cases in which the difference between the claimed invention and the prior art is some range or other variable within the claims. . . . In such a situation, the applicant must show that the particular range is critical, generally by showing that the claimed range achieves unexpected results relative to the prior art range.” In reWoodruff, 919 F.2d 1575, 16 USPQ2d 1934 (Fed. Cir. 1990).” However reviewing the five examples in the specification only three concentrations of nitric acid in a saturated hexamine solution were used, which does not support the claimed range. In Experiment 1, the concentration is 99% HNO3 which results in precipitation. In experiment 2, 70% by weight HNO3 is used however, ”It can be concluded that the overall acid concentration for the reaction is too low to produce RDX in sufficient quantities…” In experiment 3 90% HNO3 was used, “however limited product formed”. Experiments 4 and 5 also use 90% HNO3 in addition to sulfuric acid, which appears to be the optimal process. The evidence of unexpected results of a claimed range must be reasonably commensurate with the scope of the claims (See MPEP 716.02(d)). The range in claim 2, 88wt% to 90wt%, is reasonably commensurate in scope with the showing.
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.
3. Claim(s) 1, 3, 5-7, 9-11, 13-14, 16, 19-20 is/are rejected under 35 U.S.C. 103 as being unpatentable over Hale, “Nitration of urotropine using nitric acid”, J. Am. Chem. Soc. 47 (1925) 2754–2757 and Kyprianou “Synthesis of 2,4,6-Trinitrotoluene (TNT) Using Flow Chemistry” Molecules 2020, 25, 3586 1-15, Published: 6 August 2020 in view of Luo “Evaluations of kinetic parameters and critical runaway conditions in the reaction system of hexamine-nitric acid to produce RDX in a non-isothermal batch reactor.” Journal of Loss Prevention in the Process Industries 15 (2002) 119–127. The factual inquiries set forth in Graham v. John Deere Co., 383 U.S. 1, 148 USPQ 459 (1966), that are applied for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows:
Determining the scope and contents of the prior art
Hale teaches the basic reaction of the instant claims used to produce RDX on a large scale on page 2757,
Nitration of Hexamethylenetetramine Nitrate.—Table I gives the results of several representative nitrations in which nitric acid at various concentrations and at different temperatures was used. The nitrations were carried out by adding 5g. of the dried hexamethylenetetramine nitrate, obtained as described above, in small portions to the c. p. acid contained in a lOOcc. beaker. The acid was stirred only gently during the addition of the salt, as it was soon found that vigorous agitation caused a hasty reaction which tended toward a violent fuming of the mass. During the addition of the nitrate and for a short time after, the solution showed slight effervescence and the odor of formaldehyde was evident. As soon as the solution became quiet the charge was poured slowly into ice water, whereupon a white crystalline compound separated.
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The quenching was performed with ice water to initiate precipitation as in claim 9 which is below 10oC as in claim 10.
Kyprianou demonstrated the feasibility of performing nitration of 2,4-DNT to 2,4,6-TNT using a flow chemistry approach:
In recent years, considerable progress has been made in the synthesis of high-energy materials, especially in the field of military high explosives or propellants. Some of these high-energy materials can be obtained by novel eco-friendly methods of synthesis or techniques [3,4]. Nevertheless, the traditional approach is still applied, and it involves the use of hazardous concentrated acid mixtures (typically nitric and sulfuric acid as a nitrating mixture [5]). Nitration processes carried out especially at a larger scale are particularly prone to runaway exothermic reactions, and thus are of high safety concern [6]…..[page 1]
The objective of this work was to develop a safer process for the manufacturing of high purity TNT (>99%) to be used in the preparation of explosives standards at the European Commission’s Joint Research Centre. These standards are used to verify that various explosives detection devices, like explosives trace detection equipment (ETD) used at airports, perform according to the specifications laid down in the EU Commission Implemented Regulation 2015/1998 [13]. In this regard, flow chemistry was chosen as a safer alternative to the conventional method of preparing TNT. Flow chemistry—also known as continuous flow chemistry—is the process of performing chemical reactions in a reactor, which can be a pipe, tube, or more complex microstructure device. The reagents are pumped to a mixing junction and flow into the temperature-controlled reactor. The large surface area facilitates vigorous mixing due to high rates of mass transfer and fast dissipation of heat, which allows for highly exothermic reactions. Consequently, faster, safer, automated, scalable procedures can be developed, and high purity products can be obtained by applying this form of synthesis [14–16]. In the pharmaceutical sector, several highly exothermic or hazardous nitration reactions were scaled up using flow chemistry processes [17]. Energetic materials have traditionally been prepared in batch reactors. However, on some occasions, flow chemistry was successfully used as an alternative to batch synthesis [18,19]. Among explosive substances, nitroglycerin, which is also a pharmaceutical substance, attracted a significant scientific interest for translating its conventional batch synthesis into flow process [20]. The application of flow chemistry is important for processes associated with large risks. Flow chemistry mainly increases safety with well-controlled pressure, stable temperatures, homogenous mixing, and fast dissipation of heat. Moreover, lesser amounts of energetic materials are present at any time in the reactor due to the continuous flow of reagents and the removal of the synthesis products.[page 2]
The benefits of conducting the nitration of 2,4-DNT to 2,4,6-TNT using a flow chemistry approach were shown by Kyprianou. The main advantages of the flow chemistry approach included the use of safer reagents, shorter reaction times, and minimizing the risk of runaway reactions since the mixing steps take place in the reactor under continuous flow conditions.
Luo explains that the reaction of Hale, sometimes called the Woolrich process, where hexamine is reacted with nitric acid to produce RDX, is dangerous.
Although the RDX has been produced and used by many countries for a long time, its production process is not very safe so far. Numerous thermal runaway incidents and explosion catastrophes have occurred in the past. Unfortunately, its reactive hazard has not been clearly identified. The critical runaway temperature and unstable criterion at its reaction process are still unknown. The industries have to control their operating conditions very carefully to avoid the reaction system becoming a runaway situation. Therefore, we evaluate its reaction kinetic parameters from known production data of RDX in this investigation. Then, we can determine the critical runaway conditions of RDX reaction in a non-isothermal batch reactor using the transient energy and mass balance equations and evaluated kinetic parameters by numerical techniques simultaneously. Consequently, this critical runaway condition can be expressed as a function of kinetic parameters of chemical reaction, physical properties, and ambient temperature etc. Their required heat transfer coefficients in this critical condition can also be estimated. [ Luo Page 119, co. 2]
Evaluation of reaction kinetic parameters from batch reaction of RDX
The chemical reaction rate is very sensitive and affected by the temperature variation in an exothermic reaction system. Runway reaction or thermal explosion occurs in this exothermic hexamine-nitric acid reaction system in its production process. If we consider this reaction system in a batch reactor, when the total generated heat rate of reactive system exceeds removed heat rate of the ambient cooling medium, the whole system is very easy to accumulate energy and raise temperature. Then, this heat increasing system becomes unbalanced and a self-ignition reaction is triggered off. As soon as the temperature in this batch reactor reaches the critical point, the reactive system becomes a runaway situation or even explosion. [page 121 col. 1]
Luo conducts experiments with 98% nitric acid an analyzes the yield of RDX at various times and temperatures in Table 1 on page 121 and determined safe parameters for operating a batch reactor. “The batch reaction system of RDX production being either runaway or safe can be evaluated from the values of f."
Ascertaining the differences between the prior art and the claims at issue.
The prior art is directed towards a batch process while the instant claims are drawn to a flow chemistry reaction set up.
Resolving the level of ordinary skill in the pertinent art and considering objective evidence present in the application indicating obviousness or nonobviousness
Since the prior art process for making RDX was known to be dangerous in batch mode, the artisan would naturally look to flow chemistry to make the process safer as well as achieving shorter reaction times. The risk of runaway reactions would be minimized since the mixing steps take place in the reactor under continuous flow conditions. This is a so called exemplary rationale discussed in MPEP 2143, “(C) Use of known technique to improve similar devices (methods, or products) in the same way; (D) Applying a known technique to a known device (method, or product) ready for improvement to yield predictable results;” Using flow chemistry was recognized providing improvements in safety in explosives nitration. One of ordinary skill in the art would have been capable of applying this known technique disclosed by to Kyprianou to the known batchwise RDX synthesis that was ready for improvement. The results would have been predictable to one of ordinary skill in the art.
Process optimization such as changes in temperature, concentration of reagents are routine. Hale shows a clear dependence of the reaction rate on temperature and acid concentration. According to Kyprianou “The influence of key parameters, such as HNO3:DNT molar ratio, residence time, and process temperature were investigated and optimized by applying a design-of-experiments approach. We note the possibility of obtaining a high conversion rate from 2,4-DNT to TNT (>99%) in only 20 min. This significant improvement of reaction performance can be attributed to the use of a flow chemistry set up, which includes the rapid mixing in the reactor that facilitates enhanced mass transfer during the course of the reaction. It is possible to safely apply elevated temperatures due to the fast dissipation of heat, which would not be possible with the batch methods due to high risk of a runaway reaction. By comparison, in similar conditions, the conversion rate of 2,4-DNT to TNT in a batch type reaction did not exceed 58%. Although a thorough economic assessment is beyond the scope of this paper, a provisional cost assessment of reagents indicates the flow chemistry approach might be favorable.” Optimizing time, temperature and concentration is especially critical in light of the potential for runaway reactions.
4. Claim(s) 4, 15 and 18 is/are rejected under 35 U.S.C. 103 as being unpatentable over Hale and Kyprianou in view of Luo as applied to claims 1, 3, 5-7, 9-11, 13-14, 16, 19-20 above, and further in view of Dunning “The Heat of Nitrolysis of Hexamine in Nitric Acid.” Journal of the Chemical Society (1950), 2920-4. Claim 4, 15 and 18 are drawn to using 99% nitric acid as one of the flow reagents. The references above Hale and Luo use up to 98% nitric acid. The use of 99% nitric acid in this reaction is also known as shown by Dunning who used 99% acid in various experiments including Figure 3:
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The Table on page 1267 also shows a rapid rate of production of the product (I), RDX, from hexamine with 99% nitric acid.
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The experimental section on page 1268 describes “99% acid (200 g.) was cooled to a predetermined extent below 0" and finely crushed hexamine (2 g.) was added at once to the vigorously stirred acid in a thin-walled flask; the temperature rose rapidly (<30 sec.) to 0oC”
It would be obvious to use 99% nitric acid to increase the reaction rates.
5. Claim(s) 15 and 17 is/are rejected under 35 U.S.C. 103 as being unpatentable over
Hale and Kyprianou in view of Luo as applied to claims 1, 3, 5-7, 9-11, 13-14, 16, 19-20 above, and further in view of Fischer, Dennis; “Synthesis and Characterization of Guanidinium Difluoroiodate, [C(NH2)3]+[IF2O2]- and its Evaluation as an Ingredient in Agent Defeat Weapons” Zeitschrift fuer Anorganische und Allgemeine Chemie (2011), 637(6), 660-665 (abstract only). The prior art of Hale and Kyprianou in view of Luo does not use 70% nitric acid with sodium nitrite. According to Fischer abstract it is effects the same transformation. Combining two things known for the same purpose is prima facie obvious. Such salts can be added to decompose unwanted by-products in a controlled manner.
Objections
6. Claim 2 is objected to for depending from a rejected base claim, but would be allowable in independent format with all the limitations of the base claim and any intervening claim.
Conclusion
7. THIS ACTION IS MADE FINAL. 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 DAVID K O'DELL whose telephone number is (571)272-9071. The examiner can normally be reached on Monday - Friday 9:30 - 7:00 PM.
If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Clinton Brooks can be reached on 571-270-7682. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
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/DAVID K O'DELL/ Primary Examiner, Art Unit 1621
