| 摘要 |
A 2-stage process for the removal of residual solvent from crystd. ε -caprolactam(I) was described. Thus, 100 parts I contg. 2% toluene(II) (obtained by II extn. and 2-fold cry -stn. from II of crude I prepd. by the gas phase conversion of cyclohexanone oxime) was mixed with 4 parts water and fed to an evaporator operated at 135≦̸C/300mm. The product from the evaporator (contg. 1.8 % water and traces of toluene, i.e., 100 ppm) was fed to a 2nd evaporator operated at 150≦̸C / 12mm to give pure I.
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