Study on Crystal Growth Rate from the Melt of Organic Compounds

Abstract

The mechanisms and rates of growth of m CNB (chloronitrobenzene) and p NT (nitrotoluene) from the binary melt of (m CNB) - (o CNB) and (p NT) - (mNT), respectively, have been investigated using an agitated vessel.
Crystals of both compounds grow by the stepwise mechanism as surface diffusion controlling, and in the case of m CNB the screw dislocation mechanism is confirmed experimentally.
When the overall rate of growth is mainly controlled by the surface integration step, the following empirical equations are obtained :
mCNB dW/Adθ =2.00×10¹¹exp (-2.3×10³/RT) ΔT²
pNT dW/Adθ 5.64× 10⁹exp (-19.3×10³/RT) ΔT