| 摘要 |
The invention relates to the use of coil tube evaporators for concentrating aqueous extract solutions from the extraction of polyamides based on polyamide (6). A method for the production of polyamides based on polyamide (6) comprises the steps (b) one-phase or two-phase reaction of aqueous extract solutions from the extraction of polyamides based on polyamide (6), which are possibly enriched with caprolactam, aminocapronitrile, aminocaproic acid, or mixtures thereof, in a pre-reactor at pressures in the range of 5 to 40 bar and temperatures in the range of 150 to 300‹C, wherein in the two-phase reaction, the evolved gaseous phase can be separated from the liquid phase, c) discharge of the reaction mixture obtained from step b) by means of a coil tube evaporator at a temperature in the range of 220 to 300‹C with a reduction of pressure to approximately atmospheric pressure and separation of a gaseous phase, producing a liquid phase, d) further reaction of the liquid phase obtained from step c) at temperatures in the range of 240 to 300‹C and pressures in the range of atmospheric pressure to 2 bar, with a separation of a gaseous phase. ® KIPO & WIPO 2009 |
