Reference

Process for the recovery of caprolactam from waste containing nylon by extraction with alkyl phenols

Process for the recovery of caprolactam from waste containing nylon by extraction with alkyl phenols. Frentzen, Yvonne Helene; Thijert, Marcellinus Plechelmus; Zwart, Rudolf Lambertus (Dsm N.V.; Frentzen, Yvonne Helene; Thijert, Marcellinus Plechelmus Gerhardus; Zwart, Rudolf Lambertus, Neth.). PCT Int. Appl. WO 9703048 A1 30 Jan 1997, 17 pp. DESIGNATED STATES: W: CA, CN, JP, KR, MX, SG, US; RW: AT, BE, CH, DE, DK, ES, FI, FR, GB, GR, IE, IT, LU, MC, NL, PT, SE. (English). (World Intellectual Property Organization). CODEN: PIXXD2. CLASS: ICM: C07D201-12. APPLICATION: WO 1996-NL283 11 Jul 1996. PRIORITY: NL 1995-1000781 12 Jul 1995. DOCUMENT TYPE: Patent CA Section: 35 (Chemistry of Synthetic High Polymers) Section cross-reference(s): 40 The title process comprises (a) depolymg. waste contg. nylon 6 with H2O at ~200-400° to yield a second mixt. comprising depolymd. nylon 6 components, and caprolactam (I) at a concn. ~5-35%; (b) optionally, sepg. insol. material from the second mixt.; (c) extg. the second mixt. with an extn. agent, such as an alkyl phenol having a b.p. higher than that of I, to an aq. raffinate third mixt. and org. phase fourth mixt. comprising I and the extn. agent; (d) recovering I from the org. phase fourth mixt. by distn.; and (e) recycling the aq. raffinate third mixt. to step (a). Nylon 6 carpet fibers were treated as described above in a reactor (300°/100 bar/1 h) to give a slurry of monomer, cyclic and linear oligomers, and water for feed to the extn. step (100°) using dodecyl phenol (b. 190°, 10 mm Hg). The efficiency in the I purifn. with respect to sepn.Except for chemicals metioned above, 616-55-7 and 65152-07-0 are also used. of oligomers is improved. .