Ex Parte WangDownload PDFBoard of Patent Appeals and InterferencesNov 15, 201112290757 (B.P.A.I. Nov. 15, 2011) Copy Citation UNITED STATES PATENT AND TRADEMARK OFFICE __________ BEFORE THE BOARD OF PATENT APPEALS AND INTERFERENCES __________ Ex parte WEI WANG __________ Appeal 2011-007411 Application 12/290,757 Technology Center 1600 __________ Before DEMETRA J. MILLS, ERIC GRIMES, and FRANCISCO C. PRATS, Administrative Patent Judges. GRIMES, Administrative Patent Judge. DECISION ON APPEAL This is an appeal under 35 U.S.C. § 134 involving claims to a process for producing acetic acid. The Examiner has rejected the claims as obvious. We have jurisdiction under 35 U.S.C. § 6(b). We affirm. STATEMENT OF THE CASE The Specification discloses that in known methods, “[a]romatic iodide compounds are removed from acetic acid by palladium-gold acetoxylation catalysts … [which] are expensive” (Spec. 2: 16-17). The Specification Appeal 2011-007411 Application 12/290,757 2 discloses “a method for removing iodobenzene compounds from acetic acid … [by] contacting the acetic acid with palladium supported on a macroreticular ion-exchange resin” (Id. at 2: 22-24). Claims 5-9 are on appeal. Claims 6-9 have not been argued separately and therefore stand or fall with claim 5. 37 C.F.R. § 41.37(c)(1)(vii). Claim 5 reads as follows: 5. A process for producing acetic acid, said process comprising: (a) reacting methanol and carbon monoxide in the presence of a carbonylation catalyst, a triphenylphosphine oxide stabilizer, methyl iodide, water and methyl acetate to produce an acetic acid stream containing an iodobenzene compound; (b) flashing at least a portion of the acetic acid stream into a vapor stream comprising acetic acid, water, methanol, methyl acetate, methyl iodide and the iodobenzene compound, and a liquid stream comprising the catalyst and the catalyst stabilizer; (c) subjecting the vapor stream to a distillation to produce an acetic acid product stream comprising acetic acid and the iodobenzene compound; and (d) contacting the acetic acid product stream with palladium supported on a macroreticular ion-exchange resin to remove the iodobenzene. Issue The Examiner has rejected claims 5-9 under 35 U.S.C. § 103(a) as being obvious in view of Watt1 and in view of Carey,2 or Jones,3 or Fish.4 The Examiner finds that Watt discloses that “triphen[yl]phosphines were commonly used in acetic acid processes” (Answer 4) and that “iodide by- products are also produced in the reaction” (id.). The Examiner finds that 1 Watt, US 6,686,500 B1, Feb. 3, 2004 2 Carey et al., US 6,197,997 B1, Mar. 6, 2001 3 Jones et al., US 5,344,976, Sept. 6, 1994 4 Fish et al., US 5,220,058, June 15, 1993 Appeal 2011-007411 Application 12/290,757 3 Carey discloses a “process for removing iodide compounds from a liquid carboxylic acid … obtained from the Group VIII noble metal catalyzed, alkyl iodide co-catalyzed carbonylation of alcohols and/or their reactive derivatives” (id. at 5). The Examiner finds that Carey discloses that removing the iodide compound “comprises contacting the liquid carboxylic acid … with a metal loaded ion-exchange resin … wherein the metal is one or more of the metals silver, palladium or mercury” and the ion-exchange resin can be a macroreticular ion-exchange resin (id.). The Examiner concludes that “based on the above [cited references], the claimed process step to remove iodide byproducts is known, well within the purview of those of ordinary skill, and thus, prima facie obvious” (id. at 6). The Examiner reasons that although the cited references “do not explicitly teach the removal of iodobenzene, as instantly claimed, the removal of this particular byproduct would be inherent in the process[ ] of Carey” (id.). Appellant argues that the claimed process would not have been obvious because none of the cited references recognize iodobenzene as an impurity and therefore, it would not have been obvious to use palladium supported on a macroreticular ion-exchange resin to remove it (Appeal Br. 3). The issue presented is: Does the evidence of record support the Examiner’s conclusion that it would have obvious to contact an acetic acid product stream from Watt’s carbonylation process with palladium supported on a macroreticular ion-exchange resin and thereby remove iodobenzene? Appeal 2011-007411 Application 12/290,757 4 Findings of Fact 1. Watt discloses “a process for the production of acetic acid by reacting carbon monoxide with methanol … in a liquid reaction composition comprising an iridium carbonylation catalyst, methyl iodide, methyl acetate, water and acetic acid … [and] a monodentate phosphine oxide compound” (Watt, abstract). 2. Watt discloses that a “preferred monodentate phosphine oxide compound … is triphenylphosphine oxide” (id. at col. 3, ll. 23-24). 3. Watt discloses that the “acetic acid product may be recovered from the liquid reaction composition by withdrawing vapour and/or liquid from the carbonylation reactor and recovering acetic acid from the withdrawn material” (id. at col. 5, ll. 23-26). 4. Watt discloses that the “main liquid by-product from carbonylation of methanol to acetic acid is propionic acid. It’s [sic] precursors (ethyl iodide and ethyl acetate) are also formed.” (Id. at col. 6, ll. 15-17.) 5. Carey discloses that a problem associated with acetic acid produced from the Group VIII noble metal catalysed, alkyl iodide co-catalysed carbonylation of alcohols … [is that] the acetic acid and/or acetic anhydride frequently contains small amounts of iodide impurities.… [T]hese compounds … probably comprise a mixture of methyl iodide and other higher alkyl iodides, HI and iodide salts. (Id. at col. 2, ll. 30-40.) 6. Carey discloses that these impurities are particularly troublesome since they can poison many of the catalysts which are employed in subsequent chemical conversions of the acetic acid and/or acetic anhydride. Appeal 2011-007411 Application 12/290,757 5 A case in point is the catalysts used to prepare vinyl acetate from ethylene and acetic acid which are extremely sensitive to iodide impurities. (Id. at col. 2, ll. 41-46.) 7. Carey discloses a process for removing iodide compounds from a liquid carboxylic acid and/or carboxylic anhydride obtained from the Group VIII noble metal catalysed, alkyl iodide co-catalysed carbonylation of alcohols and/or their reactive derivatives which process comprises contacting the liquid carboxylic acid and/or carboxylic acid anhydride with a metal loaded ion- exchange resin … wherein the metal is one or more of the metals silver, palladium or mercury. (Id. at col. 2, ll. 48-56.) 8. Carey discloses that the “ion-exchange resin may be any suitable resin. It may be, for example, an ion-exchange gel resin, a macroreticular ion-exchange resin or indeed any other resin which experiences a volume change upon changing the nature of its solvent environment.” (Id. at col. 1, ll. 44-47.) Analysis Claim 5 is directed to a process for producing acetic acid that comprises, among other things, (a) reacting methanol and carbon monoxide in the presence of a carbonylation catalyst, a triphenylphosphine oxide stabilizer, methyl iodide, water, and methyl acetate to produce an acetic acid stream containing an iodobenzene compound, (b) flashing part of the acetic acid stream into a vapor stream and a liquid stream, (c) subjecting the vapor stream to a distillation to produce an acetic acid stream, and (d) contacting Appeal 2011-007411 Application 12/290,757 6 the acetic acid stream with palladium supported on a macroreticular ion- exchange resin to remove iodobenzene. The Examiner finds, and Appellant does not dispute, that Watt discloses the claimed process for producing acetic acid, with the exception that Watt does not disclose the presence of iodobenzene in the acetic acid product stream or the use of “palladium supported on a macroreticular ion- exchange resin to remove the iodobenzene.” Since Watt’s carbonylation reaction includes the same reactants as those required for claim 5, however, it is reasonable to conclude that iodobenzene is also produced by Watt’s process, whether or not its presence was recognized or disclosed. Carey discloses the use of palladium-loaded macroreticular ion- exchange resin for removing iodide compounds from product streams of carbonylation reactions. Thus, it would have been obvious to use Carey’s palladium-loaded macroreticular ion-exchange resin for removing iodide compounds from an acetic acid product stream produced using Watt’s process, in order to avoid poisoning catalysts used in subsequent chemical conversions of the acetic acid. It is reasonable to conclude that using Carey’s palladium-loaded macroreticular ion-exchange resin to remove iodide compounds from Watt’s acetic acid product stream would inherently remove iodobenzene (an iodide compound) from Watt’s acetic acid product stream. Appellant argues that the process of claim 5 would not have been obvious in view of the cited references because Carey only discloses the removal of C1-C10 alkyl iodides, not iodobenzene (Appeal Br. 3-4). Appeal 2011-007411 Application 12/290,757 7 This argument is not persuasive. The removal of iodobenzene from an acetic acid product stream reasonably appears to be the inherent result of a prior art process. In accordance with In re Woodruff, “discovering and claiming a new benefit of an old process cannot render the process again patentable.” 919 F. 2d 1575, 1578 (Fed. Cir. 1990). Appellant also argues that Carey discloses that “the ion-exchange resin used for removing alkyl iodide can be any suitable resin … and the metals can be any metals of Groups I to VIII of the Periodic Table” (Appeal Br. 3-4). This argument is also not persuasive. Carey specifically suggests using a “metal loaded ion exchange resin … wherein the metal is one or more of the metals silver, palladium or mercury” (FF 7) and the resin is either an ion-exchange gel resin and a macroreticular ion-exchange resin (FF 8). Thus, the combination of a macroreticular ion-exchange resin with palladium would have been an obvious choice from among the limited preferences expressed by Carey. Conclusion of Law The evidence of record supports the Examiner’s conclusion that it would have obvious to contact an acetic acid product stream from Watt’s carbonylation process with palladium supported on a macroreticular ion- exchange resin and thereby remove iodobenzene. SUMMARY We affirm the rejection of claims 5-9 under 35 U.S.C. § 103(a). Appeal 2011-007411 Application 12/290,757 8 TIME PERIOD FOR RESPONSE No time period for taking any subsequent action in connection with this appeal may be extended under 37 C.F.R. § 1.136(a). AFFIRMED lp Copy with citationCopy as parenthetical citation