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 Objections
Claims 1 is objected to because of the following informalities: Claim 1 uses the acronym DMS without first identifying the chemical compound as dimethyl sulfide. Appropriate correction is required.
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 1-9 are rejected under 35 U.S.C. 103 as being unpatentable over Ball et al. (US Pat. 2,976,273) in view of Littorin et al. (US Pat. 9,067,959).
Considering Claims 1 and 3: Ball et al. teaches a process for separating lignin and volatile reaction products from black liquor (2:40-3:14) in which the lignin contained in the black liquor is demethylated and dimethyl sulfide is produced (2:60-3:6), and dimethyl sulfide and other volatile components are withdrawn from the reactor (3:8-14; 31-40), the residual black liquor is passed to an two stage acid precipitation step using sulfuric acid (3:23-30, Example 1), followed by a separation step to recover the lignin (Example 1).
Ball et al. does not teach the claimed pressure during the removal of the dimethyl sulfide. However, Ball et al. teaches that the vapor pressure is a result effective variable and should be greater than the vapor pressure of black liquor at the temperature (1:33-44). It would have been obvious to a person of ordinary skill in the art to have optimized the pressure through routine experimentation, and the motivation to do so would have been, as Ball et al. suggests, to control the formation of the dimethyl sulfide during the demethylation reaction.
Ball et al. does not teach that any of the other volatile reaction products are recycled to the process. However, Ball et al. teaches that carbon dioxide is a volatile product produced during the separation step (3:31-40). Littorin et al. teaches recycling waste carbon dioxide streams to the precipitation step (1:47-2:3). Littorin et al. further teaches that the precipitation step produces a carbon dioxide waste stream (1:47-2:3). Ball et al. and Littorin et al. are analogous art as they are concerned with the same field of endeavor, namely lignin precipitation from black liquor. It would have been obvious to a person of ordinary skill in the art to have recycled the carbon dioxide waste streams to the process to use as an acidifying agent during the precipitation step.
Considering Claim 2: Ball et al. teaches the process as being performed continuously (2:56-60).
Considering Claim 4: Littorin et al. teaches withdrawing off gas comprising hydrogen sulfide and carbon dioxide from the second precipitation stage and recycling it back to the first precipitation stage (1:47-2:3). It would have been obvious to a person of ordinary skill in the art to have recycled the waste stream of Ball et al. to the first precipitation stage, as in Littorin et al., and the motivation to do so would have been to reduce the amount of acid needed in the precipitation stage (1:47-2:3).
Considering Claim 5: Ball et al. teaches the demethylation step as occurring at greater than 220 ºC (2:56-59).
Considering Claim 6: Ball et al. does not teach the temperature as continuously rising. 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. "[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." In re Aller, 220 F.2d 454, 456, 105 USPQ 233, 235 (CCPA 1955). See MPEP § 2144.05. It would have been obvious to a person of ordinary skill in the art to have optimized the temperature throughout the process, and the motivation to do so would have been to control the degree of demethylation and dimethyl sulfide formation.
Considering Claim 7: Ball et al. teaches the reaction time as being 1 minute to several hours (3:1-7).
Considering Claim 8: Ball et al. teaches the process as being performed continuously (2:56-60).
Considering Claim 9: Ball et al. does not teach recycling hydrogen sulfide to an oxidation step. However, Littorin et al. teaches supplying hydrogen sulfide removed from a precipitation process to an oxidizer to form sulfuric acid (5:17-45). It would have been obvious to a person of ordinary skill in the art to have sent the hydrogen sulfide of Ball et al. to an oxidizer, as in Littorin et al., and the motivation to do so would have been, as Littorin et al. suggests, to produce sulfuric acid to be used in the precipitation step (5:17-45).
Correspondence
Any inquiry concerning this communication or earlier communications from the examiner should be directed to LIAM J HEINCER whose telephone number is (571)270-3297. The examiner can normally be reached M-F 7:30-5:00.
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/LIAM J HEINCER/Primary Examiner, Art Unit 1767