MORPHOLOGY OF EPSILON-CAPROLACTAM CRYSTALS DEPENDENT ON THE CRYSTALLIZATION CONDITIONS

The morphology of caprolactam crystals is an important property because it can affect their filterability. This study shows that the morphology of caprolactam crystals depends on the water content of the mother liquor and on the applied growth kinetics. Needle-like crystals were formed during single crystal experiments under two sets of conditions: (1) at high growth rates in a water rich mother liquor and (2) at low growth rates in the absence of water. Experiments were also performed in a lab-scale batch crystallizer and in a pilot-scale continuous crystallizer but did not yield exclusively needle-like crystals.