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
Claims 1-5, 7-11, and 13-24 of J. Stubbs, US 18/121,559 (Mar. 14. 2023) are pending. Claims 2 and 21-24 drawn to the non-elected Groups (II) and (III) are withdrawn from consideration pursuant to 37 CFR 1.142(b). Claims 1, 3-5, 7-11, and 13-20 are under examination on the merits and are rejected.
Election/Restrictions
Applicant elected Group (I), 1, 6-20, 25 and 26, without traverse in the Reply to Restriction Requirement filed on December 1, 2025. Claims 2 and 21-24, to non-elected inventions of Groups (II) and (III), are maintained as withdrawn from consideration pursuant to 37 CFR 1.142(b). Multiply dependent claims 3-5 are examined with respect to the subject matter of Group (I) but are withdrawn with respect to the subject matter relating to Group (II). The restriction/election requirement is maintained as FINAL.
Pursuant to the election of species requirement Applicant elected, without traverse, the species of dimethyl aluminum isopropoxide:
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for prosecution on the merits to which the claims shall be restricted if no generic claim is finally held to be allowable. Claims 1, 3-20, 25 and 26 of elected Group (I) read on the elected species. The elected species was searched and determined to be unpatentable pursuant to §§ 102/103. The search/examination was not further extended. MPEP § 803.02 (III)(C)(2). The provisional election of species requirement is given effect and no claims are withdrawn from consideration as not reading on the elected species. MPEP § 803.02(III)(A).
Claim Interpretation
Examination requires claim terms first be construed in terms in the broadest reasonable manner during prosecution as is reasonably allowed in an effort to establish a clear record of what applicant intends to claim. See, MPEP § 2111; MPEP § 2106(II). Under a broadest reasonable interpretation, words of the claim must be given their plain meaning, unless such meaning is inconsistent with the specification. See MPEP § 2111.01.
The Claimed Invention
The reaction of claim is summarized by the Examiner below:
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Specification working Examiner 1 is summarized by the Examiner below.
Specification Example 1
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Specification at page 8, [0032].
Interpretation of “non-coordinating solvent”
Claim 1 recites “non-coordinating solvent” in the following context.
1 . . . (i) a solution comprising a compound of the formula (R)3Al and a non-coordinating solvent, with
(ii) a solution comprising a compound of the formula Al(OR1)3 and a non-coordinating solvent.
The specification defines “non-coordinating solvent” as follows:
[0013] Non coordinating solvents are those solvents which are not otherwise reactive with either of the starting materials, i.e., the trialkyl aluminum species or aluminum alkoxides, or the product of Formula (I).
In one embodiment, the non-coordinating solvent has a maximum boiling point at atmospheric pressure of about 95°C.
Exemplary non-coordinating solvents include hydrocarbons having from 5 to 8 carbon atoms along with certain aromatic compounds, optionally substituted by C1-C8 alkyl groups.
Exemplary non-coordinating solvents include n-pentane, isopentane, n-hexane, n-heptane, n-octane, cyclohexane, benzene, toluene, xylenes, and mixtures thereof.
Specification at page 3, [0013] (emphasis added). As is well known in the art, alkyl aluminum compounds (such as the instantly claimed staring materials) are Lewis acids that can complex/coordinate with lone-pair-heteroatom-containing compounds (Lewis bases), such as ether solvents. H. Lehmkuhl, 3 Angewandte Chemie International Edition in English, 107-114 (1964) (see page 107, col. 1). This is a chemical reaction. Coordination or a coordinate covalent bond (also known as a dative bond, dipolar bond, or coordinate bond) is two-electron covalent bond in which the two electrons derive from the same atom. See e.g., IUPAC, Compendium of Chemical Terminology, Gold Book, page 344 of 1622, “coordination” (the "Gold Book") (2014).
In view of the forgoing, the term “non-coordinating solvent” is broadly and reasonably interpreted, consistently with the specification, as a solvent that does not coordinate with (e.g., lone-pair heteroatom containing solvents are excluded) or otherwise react with, the claimed (R)3Al or Al(OR1)3 starting materials under the conditions employed to synthesize the claimed reaction product of formula (I).
Withdrawal Claim Rejections 35 U.S.C. 112(b)
Rejection of claim 12 under 35 U.S.C. 112(b) as being indefinite for recitation of exemplary claim language “such as” is withdrawn in view of Applicant’s cancellation of this claim.
Withdrawal Claim Rejections - 35 USC § 102 (AIA )
Rejection of claims under 35 U.S.C. 102(a)(1) as being anticipated by E. Brandt et al., 30 Journal of Vacuum Science and Technology A, 1-15 (2012) (“Brandt”) is withdrawn in view of Applicant’s 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.
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 AIA 35 U.S.C. 103(a) 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, 3-5, 7-11, and 13-20 are rejected under 35 U.S.C. 103 as obvious over E. Brandt et al., 30 Journal of Vacuum Science and Technology A, 1-15 (2012) (“Brandt”) and of M. Buschhoff et al., US 3,894,066 (1975) (“Buschhoff”) in view of secondary art W. Koh et al., 304 Thin Solid Films, 222-224 (1997); N. G. Anderson, PRACTICAL PROCESS & RESEARCH DEVELOPMENT, 81-111 (2000) (“Anderson”); Y. Kim et al., US 2005/0271817 (2005) (“Kim”); Paul, Handbook of Industrial Mixing Science and Practice, 301-477 (2004) (“Paul”); and F. Streiff et al., Don't overlook static-mixer reactors, 101 Chemical Engineering 101, 76-82 (1994) (“Streiff”)
E. Brandt et al., 30 Journal of Vacuum Science and Technology A, 1-15 (2012) (“Brandt”)
Brandt teaches a study of aluminum oxide atomic layer deposition (ALD) on polymers using dimethylaluminum isopropoxide and water as reactants. Brandt at Abstract
Brandt teaches the following process for preparing dimethylaluminum isopropoxide (the elected species).
In an inert atmosphere (N2, glove bag), aluminum isopropoxide (22 g, 0.11 mol, Aldrich) was added to a dry three-neck round-bottom flask equipped with a pressure equalizing addition funnel, a reflux condenser mounted with a gas inlet, and a stir bar. The assembly was transferred to an inert (Ar) manifold system. A constant positive pressure of Ar was maintained throughout the reaction.
A solution of trimethylaluminum in hexanes (100 mL, 2.0 M, 0.20 mol, Aldrich) was transferred via cannula to the addition funnel. The solution of trimethylaluminum was then added dropwise over 15 min to the stirred solid aluminum isopropoxide, cooled with a dry ice/methanol bath.
The reaction mixture was allowed to warm to room temperature and subsequently heated to gentle reflux for 30 min. The volatile material was removed by distillation at atmospheric pressure under Ar. The residual liquid was then decanted to a round-bottom flask in an inert atmosphere and distilled in vacuo (90 °C) to afford the title compound as a colorless liquid.
Brandt at paragraph bridging pages 3-4.
This reaction is summarized by the Examiner as follows:
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In sum, Brandt teaches synthesis of dimethylaluminum isopropoxide by adding a solution of trimethylaluminum (Al(CH3)3) in solvent hexanes to solid aluminum isopropoxide (Al(OiPr)3), to form a mixture of the two in the non-coordinating solvent hexanes.
Differences between Brandt and Claim 1
It is first noted that, while Brandt first adds solid aluminum isopropoxide to the reaction flask, Brandt still teaches claim 1 limitations of:
Claim 1 . . . the process comprising mixing, wherein the mixing is conducted within a static mixer,
(i) a solution comprising a compound of the formula (R)3Al and a noncoordinating solvent, with
(ii) a solution comprising a compound of the formula Al(OR1)3 and a non-coordinating solvent.
for the following reasons. Upon Brandt’s addition of a solution of trimethylaluminum (Al(CH3)3) in hexanes to the solid aluminum isopropoxide (Al(OiPr)3), a second cooled (about -72 °C) solution results, which second solution comprises each of the claimed reactants Al(CH3)3 and Al(OiPr)3 in a single hexane phase that is mixed.
Brandt only differs from claim 1 in not teaching the claim 1 limitation of “wherein the mixing is conducted within a static mixer”.
M. Buschhoff et al., US 3,894,066 (1975) (“Buschhoff”)
In one embodiment, Buschhoff teaches reaction of “higher alkyl aluminum compounds” of the formula RxAlCl3-x with aluminum alcoholates of the formula Al(OR’)3, to give R2AlOR’ as follows:
RxAlCl3-x (where x is 3) + Al(OR’)3 [Symbol font/0xAE] R2AlOR’
Buschhoff at col.1 line 51 thought col. 2, line 5.
Note that in Buschhoff’s above summarized general method, when x is 3, the first formula becomes R3Al. In working Example 1, Buschhoff teaches synthesis of dioctylaluminum isopropylate by adding, with stirring at a temperature of 85-95°C, aluminum isopropylate (Al(OiPr)3) to trioctyl aluminum (Al(octyl)3), in the absence of solvent. Buschhoff at col. 4, lines 1-11. In Examples 2-10, 12 and 13, Buschhoff teaches similar syntheses with various R (alkyl) groups.
Buschhoff working Examples 1 and 2 are representative and summarized by the Examiner below.
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In Example 1, Buschhoff reports obtaining 1130 g (MW = 312.30, 3.6 moles) of dioctylaluminum isopropylate was obtained. Buschhoff at col. 4, lines 8-9. As Buschhoff generally teaches (see paragraph below), this is essentially a quantitative yield.
That is, both the aluminum isopropylate (Al(OiPr)3) and trioctyl aluminum (Al(octyl)3) starting materials are each completely converted to product dioctylaluminum isopropylate.
Yields are practically quantitative. Technical grade starting materials can also be employed. In this case, the reaction products are usually lightly colored and often contain small amounts of suspended matter. These reaction products nevertheless can be further processed without disadvantage. No purification is necessary.
Buschhoff at col. 3, lines 5-16 (emphasis added). Buschhoff’s working examples do not employ a solvent; however, Buschhoff teaches that an inert solvent may be employed as follows:
The reaction can also take place in the presence of an inert organic solvent. The higher alkyl aluminum alcoholates and alkyl alkoxy aluminum chlorides are, with few exceptions, sensitive to atmospheric oxygen and water.
Buschhoff at col. 3, lines 5-16 (emphasis added).
Paul, Handbook of Industrial Mixing Science and Practice, 301-477 (2004) (“Paul”)
Paul teaches that pipeline mixing is often used in industrial practice and in many cases the pipe, especially when equipped with static mixing internals, is a better place to mix and more economical than a vessel. Paul at page 391. Paul teaches that it is very clear that the value of pipeline mixing technology in the process industry far exceeds the equipment capital cost and investment in pipeline equipment is small compared to that of in-tank dynamic agitators and other mechanical mixing devices, but is increasing. Paul at page 392, 1st paragraph. Paul teaches that this growth results largely from static mixers having proven their capability, not only in bulk blending and mixing, but also in applications involving the dispersion of immiscible fluids, heat transfer, interphase mass transfer, and establishing plug flow in tubular reactors. Paul at page 392, 1st paragraph. Paul teaches that since static mixers have no moving parts, they are low maintenance and sealing problems are nonexistent. Paul at page 392, 2nd paragraph. Paul teaches that:
Static mixers are the dominant design choice for motionless pipeline mixing. They are essential in the laminar flow regime. They are well established in turbulent processes, both single and multiphase, due to their simplicity, compactness, and energy efficiency. Properly designed static mixers offer predictable performance and operate over a broad range of flow conditions with high reliability. Static mixer design options and basic design principles are described in the following sections.
Paul at page 397, 2nd paragraph (emphasis added). Paul further teaches that static mixing devices are readily available and highly engineered for continuous operation. Paul at page 399, 2nd full paragraph. Paul teaches that very many commercial scale applications are efficiently handled with in-line static mixing equipment and suitable for homogeneous chemical reactions. Paul at page 404, 7-4 and 7-4.1.
F. Streiff et al., Don't overlook static-mixer reactors, 101 Chemical Engineering 101, 76-82 (1994) (“Streiff”)
Streiff teaches that a static mixing unit (Figure 1) consists of a series of stationary, motionless guiding elements placed lengthwise in a pipe, duct or column, where fluids are mixed by utilizing flow (pumping) energy. Streiff at page 77, col. 1.
Streiff teaches that static mixers combines the fluids thoroughly but also enhances heat and mass transfer and provides a narrow residence-time distribution and all of these features are desirable in a reactor. Streiff at page 77, col. 1.
Streiff teaches that static-mixer reactors are usually employed as continuous tubular reactors operating in plug-flow fashion and offer many advantages over stirred tanks, such as:
• Compactness and low capital cost
• Low energy consumption and other operating expense
• Negligible wear and no moving parts, which minimizes maintenance
• Lack of penetrating rotating shafts and seals, which provides closed-system operation
• Short mixing time, and well-defined mixing behavior
• Narrow residence-time distribution
• Performance independent of pressure and temperature
Streiff at page 77, col. 1.
W. Koh et al., 304 Thin Solid Films, 222-224 (1997)
Koh teaches that dimethylaluminum isopropoxide can be prepared simply by mixing trimethylaluminum (Al(CH3)3) with aluminum isopropoxide (Al(O-iC3H7)3 at room temperature. Koh at page 222, col. 2.
N. G. Anderson, PRACTICAL PROCESS & RESEARCH DEVELOPMENT, 81-111 (2000) (“Anderson”)
Anderson teaches that solvents are selected to increase reaction rates, to increase the reproducibility and ease of running reactions, and to ensure that the desired quality and yield of product is reached and that other important considerations are to decrease waste and allow for efficient solvent recovery and reuse. Anderson at page 81. Anderson teaches routine methods of solvent selection in organic synthesis. See Anderson at page 83 et seq. In Table 4.3, Anderson lists characteristics of many solvents that are useful for scale-up operations. Anderson at pages 85-88. Anderson Table 1 lists toluene, xylenes, heptane, and cyclohexane as suitable for reaction scaleup. Anderson further teaches that recovery and reuse of solvents may have great financial impact for manufacturing operations. Anderson at page 102. Anderson thus teaches that solvent selection is a result-effective variable. MPEP § 2144.05(II)(B).
Y. Kim et al., US 2005/0271817 (2005) (“Kim”)
Kim is cited here as motivating one of ordinary skill to explore synthetic optimization and larger scale production of dimethylaluminum isopropoxide,
Kim teaches that aluminum oxide is useful to form a dielectric layer on a silicon substrate. Kim at page 1, [0002]. Kim teaches a process for fabricating an aluminum oxide film having good uniformity and conformality at a lower temperature using an atomic layer deposition process. Kim at page 1, [0006]. Kim teaches that a preferred aluminum source is dimethylaluminum isopropoxide (the instantly elected species). Kim at page 2, [0020]. In Example 1, Kim teaches atomic layer deposition of dimethylaluminum isopropoxide on a silicon substrate to obtain an aluminum oxide film having a thickness of 3.2 nm. Kim at page 2, [0028].
Obviousness Rationale
Claims 1, 3-5 and 7-8 are obvious because one of ordinary skill is motivated to synthesize dimethylaluminum isopropoxide (the elected species, in view of its utility taught by Kim) whereby a solution comprising a compound of the formula (Me)3Al and a non-coordinating hydrocarbon solvent (for example, any of toluene, xylenes, heptane, and cyclohexane as taught by Anderson or hexane as taught by Brandt) is mixed with a solution comprising a compound of the formula Al(OiPr)3 and the same non-coordinating solvent, using a continuous static mixing process (as taught by Paul or Streiff). One of ordinary skill is so motivated to employ a non-coordinating hydrocarbon solvent, because Brandt teaches adding a solution of trimethylaluminum (Al(CH3)3) in (per claim 8) hexanes to solid aluminum isopropoxide (Al(OiPr)3) and Buschhoff teaches that for such reactants, the reaction can also take place in the presence of an inert organic solvent. Buschhoff at col. 3, lines 5-16 (emphasis added). One of ordinary skill is particularly motivated to employ the Al(OiPr)3 (which is a solid) in a hydrocarbon solvent because Brandt teaches that it is solid and one of ordinary skill would predict that its use as a solution would provide ease of fluid mixing, for example using a continuous static mixing process (as taught by Paul or Streiff).
One of ordinary skill would understand from Buschhoff (essentially teaching that any inert solvent will do and the reaction is essentially quantitative) that solvent choice is not particularly limiting with respect to whether the reaction takes place in high yield. And understand from Brandt’s use of hexane for trimethylaluminum solution addition to solid Al(OiPr)3, that hydrocarbon solvents are generally suitable for the reaction. This is further bolstered by Koh’s teaching that dimethylaluminum isopropoxide can be prepared simply by mixing trimethylaluminum (Al(CH3)3) with aluminum isopropoxide (Al(O-iC3H7)3 at room temperature. Koh at page 222, col. 2.
Here, the proposed mixing of hydrocarbon solutions of (Me)3Al and Al(OiPr)3 is particularly suited for use in a simplistic pipeline reactor, (such as a static mixer as taught by Paul or Streiff) because the reaction is essentially quantitative in yield; that is, both the aluminum isopropylate (Al(OiPr)3) and trioctyl aluminum (Al(octyl)3) starting materials are each completely converted to product dioctylaluminum isopropylate. Buschhoff at col. 3, lines 5-16. Claims 1, 3-5 and 7-8 are obvious, the above-proposed rationale meeting each and every limitation.
Claims 9-11, reciting alternative hydrocarbon solvents:
9. The process of claim 1, wherein the non-coordinating solvent is chosen from benzene, toluene, and xylenes.
10. The process of claim 1, wherein the non-coordinating solvent is chosen from a heavier, high boiling, hydrocarbon having 12 to 18 carbon atoms.
11. The process of claim 10, wherein the non-coordinating solvent is chosen from hydrocarbons n-dodecane, and n-tetradecane, and isomers thereof.
are obvious variations over the cited art. As taught by Anderson solvent selection is a result-effective variable in the art of organic synthesis. MPEP § 2144.05(II)(B). Further, as discussed above, one of ordinary skill would understand from Buschhoff (essentially teaching that any inert solvent will do and the reaction is essentially quantitative) that solvent choice is not particularly limiting with respect to whether the reaction takes place in high yield. And understand from Brandt’s use of hexane for trimethylaluminum solution addition to solid Al(OiPr)3, that hydrocarbon solvents are generally suitable for the reaction. This is further bolstered by Koh’s teaching that dimethylaluminum isopropoxide can be prepared simply by mixing trimethylaluminum (Al(CH3)3) with aluminum isopropoxide (Al(O-iC3H7)3 at room temperature. Koh at page 222, col. 2. Essentially, the art teaches one of ordinary skill that one hydrocarbon solvent is as good as another in the cited reaction of (Me)3Al + Al(OiPr)3 [Symbol font/0xAE] (Me)2AlOiPr. One of ordinary skill is motivated to employ any of the hydrocarbons recited in claims 9-11 as alternatively useable in the cited reaction. For example, one of ordinary skill is motivated to employ hydrocarbon stock solvents on hand or prepared on site or that can otherwise be obtained economically.
Claims 13-15, reciting alternative temperature ranges are obvious for the following reasons. Generally, differences in concentration or temperature will not support the patentability of subject matter encompassed by the prior art unless there is evidence indicating such concentration or temperature is critical. MPEP § 2144.04(II)(A) (citing In re Aller, 220 F.2d 454, 456, 105 USPQ 233, 235 (CCPA 1955) ("[w]here the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation”). Here, Koh’s teaches that dimethylaluminum isopropoxide can be prepared simply by mixing trimethylaluminum (Al(CH3)3) with aluminum isopropoxide (Al(O-iC3H7)3 at room temperature. Koh at page 222, col. 2. Thus, depending upon the equipment and particular hydrocarbon solvent used, one of ordinary skill is motivated to optimize starting from room temperature, which falls within each of the claimed temperature ranges. In the case where the claimed ranges "overlap or lie inside ranges disclosed by the prior art" a prima facie case of obviousness exists. MPEP § 2144.05(I).
Claim 16 is obvious for the following reasons. Claim 16 recites:
16. The process of claim 1, wherein the mixing is conducted within two or more static mixers connected serially.
With regard to serially connected static mixers, the specification teaches that:
[0018] Additionally, in one embodiment, one or more static mixer(s) is(are) utilized. If more than one is utilized, the mixers may be joined in series to facilitate mixing and reaction of the starting materials. Such static mixers are widely available commercially, for example, from McMaster-Carr (www.mcmaster.com).
Specification at pages 5-6, [0018]. Claim 16 is an obvious variation over the cited art. Streiff teaches that a static mixing unit (Figure 1) consists of a series of stationary, motionless guiding elements placed lengthwise in a pipe, duct or column, where fluids are mixed by utilizing flow (pumping) energy. Streiff at page 77, col. 1. Thus, a static mixture is simply a reaction vessel (e.g., a pipe) with guiding elements that promote mixing. One of ordinary skill is motivated to connect one static mixer (e.g., a pipe) simply to extend the reaction mixture capacity; or, alternatively, connect two shorter pipe mixers together to reach the overall desired length/capacity. See, MPEP § 2144.04 (VI)B (citing In re Harza, 274 F.2d 669, 124 USPQ 378 (CCPA 1960) (although the reference did not disclose a plurality of ribs, the court held that mere duplication of parts has no patentable significance unless a new and unexpected result is produced)).
Claims 17 and 18, directed to concentration ranges of (R)3Al and Al(OR1)3 are obvious for the following reasons. Generally, differences in concentration or temperature will not support the patentability of subject matter encompassed by the prior art unless there is evidence indicating such concentration or temperature is critical. MPEP § 2144.04(II)(A) (citing In re Aller, 220 F.2d 454, 456, 105 USPQ 233, 235 (CCPA 1955). Here, one of ordinary skill is apprised that the specific molar concentrations of (Me)3Al and Al(OiPr)3 are not particularly limiting because Koh teaches that dimethylaluminum isopropoxide can be prepared simply by their solventless mixing at room temperature in a 2:1 ratio. Koh at page 222, col. 2. Further, Brandt teaches “[a] solution of trimethylaluminum in hexanes (100 mL, 2.0 M, 0.20 mol, Aldrich)” was reacted with solid Al(OiPr)3, which falls within the claim 17 concentration range. Brandt at paragraph bridging pages 3-4. One of ordinary skill is motivated to optimize the molar concentrations of (Me)3Al and Al(OiPr)3, depending upon the equipment and hydrocarbon solvent employed (e.g., the capacity of the static mixer, heat of reaction and heat transfer). Towards this end, the starting point of 2.0 M as suggested by Brandt, which falls within the claimed ranges, is a reasonable starting point. In the case where the claimed ranges "overlap or lie inside ranges disclosed by the prior art" a prima facie case of obviousness exists. MPEP § 2144.05(I).
Claims 19 and 20 are obvious because one of ordinary skill is motivated to employ purified (Me)3Al and Al(OiPr)3 to obtain the desired dimethylaluminum isopropoxide ((Me)2AlOiPr). For example, respecting claim 17, one of ordinary skill having colored or otherwise impure (Me)3Al is motivated to purify by distillation before employing it in the above proposed reaction. Similarly, (per claim 20) one of ordinary skill having cloudy Al(OiPr)3 or compromised with foreign particulates is motivated to perform a filtration prior to its use. See, MPEP § 2144.04 (VII).
Applicant’s Argument
Applicant’s Argument
Applicant argues that the claimed invention relates to a flow chemistry process for preparing dialkylaluminum alkoxides using static mixers, non-coordinating solvents, and controlled temperature ranges (10-95°C). This process achieves superior product purity with low trimer/tetramer content (no more than 1200 ppm of trimer or tetramer, and no more than 2500 ppm combined) compared to prior art batch methods. Reply at page 5-6. Applicant argues that the synergistic combination of flow chemistry with static mixers provides critical advantages for the highly exothermic reaction between pyrophoric trimethylaluminum and solid aluminum isopropoxide described in the specification. Reply at page 6. Applicant cites the specification stating that conventional batch reactions encounter poor mixing and localized hot spots even with slow addition of reactants, making scale-up problematic. Reply at page 6 (citing specification at page 1, [0003]. Applicant argues that the claimed flow process with static mixers overcomes these limitations by ensuring rapid, uniform mixing that dissipates reaction heat efficiently. Reply at page 6.
Examiner Response
This argument is not persuasive for the following reasons. Applicant argues that
This process achieves superior product purity with low trimer/tetramer content (no more than 1200 ppm of trimer or tetramer, and no more than 2500 ppm combined) compared to prior art batch methods.
Reply at lines bridging pages 5-6 (emphasis added). Applicant is apparently arguing that the specification’s asserted low trimer/tetramer content is unexpected over prior art batch processes.1 However, Applicant has made no direct comparison with the prior art. Specification Example 4, appears to be a small-scale batch process including one equivalent of ethanol, however, the specification reports no tetramer/trimer content and the solvent mixture is different than Brandt’s single solvent hexanes. As such, Applicant has not made a comparison with the closest prior art. MPEP § 716.02(e) (“[proffered unexpected results] must compare the claimed subject matter with the closest prior art to be effective to rebut a prima facie case of obviousness”).
Furthermore, Streiff teaches this very issue argued by Applicant regarding mixing in exothermic reactions.
And the problem is compounded if the reaction is highly exothermic or endothermic, because there may be a significant temperature difference between the center and the inside tube wall, leading to undesired reactions, lack of product uniformity, and discoloration. This wide residence-time distribution and unfavorable time-temperature distribution in a tubular reactor can be reduced by using static mixers. They enhance radial mixing, and simultaneously increase heat transfer four to ten times due to forced radial convection.
Streiff at page 79 cols. 1-2.2 As such, one of ordinary skill would expect that employing a static mixing process in a highly exothermic reaction would lead to better mixing and avoidance of hot spots and avoidance of undesired reactions.
Applicant’s Argument
Applicant further argues that nothing in the Paul or Streiff references would suggest that reacting (Me)3Al and Al(OiPr)3 would be suited for static mixing. Koh describes chemical vapor deposition of Al2O3 films. Reply at page 6. Applicant argues that Koh simply mentions that dimethylaluminum isoproxide can be synthesized at room temperature by mixing the reactants in a 2: 1 ratio under inert atmosphere and mentions nothing about yields or purity. Id. Applicant argues that neither Brandt nor the secondary references provide any teaching regarding flow chemistry or static mixer technology to produce dimethylaluminum isoproxide; and in fact, Brandt describes a solution of trimethylaluminum added to a solid aluminum isopropoxide, which is not available for static mixer technology. Id.
Examiner Response
One cannot show nonobviousness by attacking references individually where the rejections are based on combinations of references. MPEP § 2145(IV). Here the art as a whole suggests that the proposed exothermic mixing of hydrocarbon solutions of (Me)3Al and Al(OiPr)3 is particularly suited for use in a static mixer as taught by Paul or Streiff because the reaction is essentially quantitative in yield, where no side products are formed; that is, both the aluminum isopropylate (Al(OiPr)3) and trioctyl aluminum (Al(octyl)3) starting materials are each completely converted to product dioctylaluminum isopropylate. Buschhoff at col. 3, lines 5-16. As taught by Streiff, unfavorable time-temperature distribution in a tubular reactor can be reduced by using static mixers because they enhance radial mixing, and simultaneously increase heat transfer four to ten times due to forced radial convection. Streiff at page 79 col. 2
Conclusion
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.
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ALEXANDER R. PAGANO
Examiner
Art Unit 1692
/ALEXANDER R PAGANO/Primary Examiner, Art Unit 1692
1 In specification working Examples 1 and 2, a static mixer was used. Specification at pages 8-9. In Example 1, after distillation, the product’s trimer content was determined to be 400 ppm and the tetramer’s content was determined to be 1200 ppm. Specification at page 8, [0032]. In Example 2, after distillation, the product’s trimer content was determined to be 170 ppm and the tetramer’s content was determined to be 490 ppm. Specification at page 9, [0033].
2 It is readily ascertainable to one of ordinary skill that the claimed reaction is highly exothermic, for example, Grosse teaches such. Grosse teaches synthesis of dimethylaluminum isopropoxide in a simple solventless mixing process as follows:
11. Dimethylaluminum methoxide.—Aluminum methoxide19 (5.80 g., 48 millimoles) was placed in a distilling flask and aluminum trimethyl (6.95 g., 96 millimoles) added portion wise. Considerable heat was evolved during the addition. The mixture was heated for 20 minutes at 100° and finally the temperature was raised to 135°. The mixture became completely liquid and remained liquid at room temperature. It distilled chiefly at 119-122° at 50 mm., leaving a residue of 1.0 g.
A. Grosse, et al., 5 Organoaluminum Compounds: I. Methods of Preparation I, The Journal of Organic Chemistry, 106-121(1940) (“Grosse”) (see Grosse at page 118).
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