| 摘要 |
Method for preparing caprolactam by heating 6-aminocapric acid nitrile in the presence of heterogeneous catalysts ans water under elevated pressure, wherein (a) 6-aminocapric acid nitrile or a mixture containing essentially 6-aminocapric acid nitrile as well as water and a low-boiling or a high-boiling alcohol is heated in the presence of a heterogeneous catalyst in a reactor A to produce a mixture (I); then (b) mixture (I) is distilled, yielding a head fraction, caprolactam and a bottom product, with any ammonia in mixture (I) being removed prior to distillation; and then (c1) the head fraction is fed into the reactor of step (a), with the head fraction optionally being mixed with the alcohol and/or water and/or 6-aminocapric nitrile used in step (a) before being fed into reactor (A); or (c2) the head fraction, optionally with the bottom product from step (b), is fed into a reactor (B), the first fraction optionally being mixed with the alcohol and/or water and/or 6-aminocapric acid nitrile before being fed into reactor (B), and then analogously to step (b) caprolactam is produced by distillation; and either (d1) the bottom product from step (b) is fed into reactor A of step (a); or (d2) optionally water and possibly a low-boiling or a high-boiling alcohol are added to the bottom product which then, analogously to step (a) is heated in a reactor (C) to give a reaction product which is distilled to yield caprolactam; or (d3) water is added to the bottom product which is heated in a reactor (D) without added catalyst to give a reaction product which is distilled to yield caprolactam; or (d4) water and a base are added to the bottom product which is heated in reactor (E) to give a reaction product which is distilled to yield caprolactam. |
