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 .
Claim Rejections - 35 USC § 103
In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis (i.e., changing from AIA to pre-AIA ) for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status.
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.
Claim(s) 1-10, 15, and 16 is/are rejected under 35 U.S.C. 103 as being unpatentable over De Brouwer et al. (WO 2012/150560) in view of Shaw (US 4,859,803), and Oberholtzer et al. (US 6,448,453).
The claims are drawn to a process for preparing bisphenol A (BPA) isomers by condensing raw phenol and raw acetone in the presence of a catalyst system, wherein the catalyst system comprises an ion exchange resin catalyst and a sulfur-containing co-catalyst, and wherein alpha-methylstyrene is present the condensation step in an amount higher than 1 ppm with respect to the total weight of the raw phenol. Further limitations include the presence of 4-cumylphenol in the condensation step, and a step for separating the mixture obtained after the condensation step into a bisphenol A fraction comprising isomers thereof, and a phenol fraction, wherein the phenol fraction comprises unreacted phenol and at least one impurity formed due to the presence of alpha-methylstyrene.
De Brouwer et al. teach a process for producing bisphenol A by a condensation reaction between phenols and ketones, wherein the reaction is conducted in the presence of an ion exchange resin catalyst having an attached dimethylthiazolidine promoter (abstract). The bisphenol A that is produced may be used to produce polycarbonates by processes such as interfacial polymerization and melt polymerization (0073).
De Brouwer et al. teach that promoter systems used with an ion exchange catalyst may be bulk, wherein the promoter species is disposed in the reaction medium, or attached, wherein the promoter is attached to a portion of the catalyst system (0097). The phenol compound may be phenol itself, and the ketone may be acetone, in which case 2,2-bis-(4-hydroxyphenyl)-propane, i.e., bisphenol A is produced. The phenol starting material may be commercial grade, meaning that it may contain measurable levels of typical impurities, including, inter alia, alpha-methylstyrene (0107, 0109-0110).
The promoter, dimethylthiazolidine, is preferably attached to the ion exchange resin in the process taught by De Brouwer et al. (0120, 0125).
In conventional bisphenol manufacturing processes, a stream of about 10-12% bisphenol A is recycled to the main reactor, i.e., as an educt in the condensation reaction. The recycle stream may contain 10-14 wt.% p,p-BPA, 2 to 4 wt.% o,p-BPA, and 4 to 8 wt.% of other BPA impurities, without reducing the lifetime of the catalyst (0132-0133).
Shaw teaches a process for the preparation of bisphenols by treating a phenol with a ketone in the presence of a cation exchange resin and a mercaptan co-catalyst (abstract). Specifically, Shaw teaches that the addition of a mercaptan, along with the ion exchange resin catalyst, adversely effects the formation of undesirable cyclic dimers. More specifically, Shaw teaches that the resin is not modified to any substantial degree by the mercaptan, i.e., the mercaptan is free in the reaction solution. Suitable mercaptans include those of the formula R-SH, wherein R is hydrogen or an organic group such as aliphatic, cycloaliphatic, aryl, or heterocyclic compounds containing one or more free mercaptan groups. Alkyl mercaptans are preferred (col. 1, line 35 to col. 2, line 43).
Shaw further teaches that the bisphenol A product is passed to a concentrator where acetone, phenol, and free mercaptan are removed (separation step). The crude bisphenol A product is then passed to a crystallization zone to form an adduct of phenol and bisphenol A which separates out as crystals. After washing with phenol, filtering and the like, the bisphenol A is recovered from the adduct. Like De Brouwer et al., Shaw teaches that the recovered product is recycled back to the condensation zone (col. 3, lines 27 to 60).
The instant claims are rendered obvious by the combined reference teachings, since both De Brouwer et al. and Shaw teach the preparation of bisphenol A by condensing phenol and acetone in the presence of an ion exchange resin catalyst and a sulfur-containing co-catalyst. It is preferred by Brouwer et al. that the sulfur-containing co-catalyst is at least partially attached to the ion exchange resin, although it is acknowledged that the promoter system can be bulk, i.e., free from the ion exchange resin. Shaw specifically teaches the use of free co-catalysts, and teaches that their presence in the reaction solution minimizer the formation of undesirable dimers.
Neither Brouwer et al. nor Shaw expressly teaches the presence of at least 1 ppm of alpha-methylstyrene in the condensation reaction of phenol and acetone, or the presence of 4-cumyl alcohol; however, as stated above, De Brouwer et al. teach that the phenol starting material may be commercial grade, meaning that it may contain measurable levels of typical impurities, including, inter alia, alpha-methylstyrene. Both Brouwer et al. and Shaw teach that the presence of the sulfur-containing co-catalyst with the ion exchange resin catalyst allows the condensation reaction to occur in the presence of impurities without reducing the lifetime of the catalyst, and in the case of Shaw, minimizing the formation of undesired dimers.
With regard to the presence of 4-cumylphenol, a person having ordinary skill in the art would recognize that any alpha-methylstyrene present in the raw phenol may react with phenol to form some amount of 4-cumylphenol. To this point, Oberholtzer et al. specifically teaches a process for making cumylphenol, wherein phenol and alpha-methylstyrene are reacted to produce the compound.
Claim(s) 11-14 is/are rejected under 35 U.S.C. 103 as being unpatentable over De Brouwer et al., Shaw, and Oberholtzer et al. as applied to claims 1-10, 15, and 16 above, and further in view of Miyamoto et al. (US 6,750,314)
The instant claims are drawn to a process for preparing a polycarbonate by first obtaining bisphenol A according to the process of claim 1, and then polymerizing the bisphenol A. Further limitations include the process being an interphase phosgenation process using at least one chain terminator.
As stated in the rejection above, De Brouwer et al. teach that that the bisphenol A that is produced may be used to produce polycarbonates by processes such as interfacial polymerization and melt polymerization (0073).
Miyamoto et al. teach a process for the preparation of polycarbonates by first producing bisphenol A by condensation of phenol and acetone, followed by purification (by crystallization). The bisphenol A is then held in a molten state and supplied to a polymerization step, or a bisphenol A is obtained by distillation of phenol from said bisphenol A/phenol molten state and then mixed with a carbonic acid diester (melt method), or mixed with an aqueous alkali solution and phosgene (interfacial method), so as to carry out the polymerization step (col. 2, line 65 to col. 6, line 67). A suitable chain terminator may be added as the case requires, based on the amount of the bisphenol A in the aqueous phase (col. 9, lines 24 to 45; example 13).
The instant claims are rendered obvious by the combined reference teachings, as De Brouwer et al. teach that that the bisphenol A that is produced may be used to produce polycarbonates by processes such as interfacial polymerization and melt polymerization; a person having ordinary skill in the art would have been able to look to Miyamoto et al. for a more detailed teaching of producing polycarbonates from bisphenol A, e.g., using the interfacial method.
Claim 17 is objected to as being dependent upon a rejected base claim, but would be allowable if rewritten in independent form including all of the limitations of the base claim and any intervening claims. The prior art does not teach or suggest conducting the condensation of phenol and acetone in the further presence of a polymerization monomer.
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/SIKARL A WITHERSPOON/Primary Examiner, Art Unit 1692