Acta Phys. -Chim. Sin. ›› 2013, Vol. 29 ›› Issue (01): 23-29.doi: 10.3866/PKU.WHXB201210123

• THERMODYNAMICS, KINETICS, AND STRUCTURAL CHEMISTRY • Previous Articles     Next Articles

Molecular Dynamics Simulations on Hydrolysis of Zinc Acetate in Supercritical Water

WANG Xiao-Juan, LI Zhi-Yi, LIU Zhi-Jun   

  1. Institute of Fluid and Powder Engineering, College of Chemical Machinery, Dalian University of Technology, Dalian 116023, Liaoning Province, P. R. China
  • Received:2012-08-09 Revised:2012-10-12 Published:2012-12-14
  • Supported by:

    The project was supported by the Fundamental Research Funds for the Central Universities, China (852001).

Abstract:

Zinc oxide (ZnO) is a multifunctional material with wide applications in chemical engineering.Hydrothermal synthesis of ZnO under supercritical conditions from salt solutions containing zinc ions is an environmentally safe process. Two reaction steps are involved, zinc hydroxide sol formation and dehydration from the sol. However, little is known about the underlying mechanism. In this study, molecular dynamics simulations were performed to investigate the structural and thermodynamic changes in the zinc acetate hydrolysis process, i.e., Zn(CH3COO)2, in supercritical water (SCW). Our results show that Zn(CH3COO)2 is prone to aggregate in SCW. On average, one Zn2+ ion coordinates with five CH3COO- species and one H2O molecule, forming an octahedral configuration. WHowever, more water molecules bind Zn2+ at the SCW interface to form Zn(CH3COO)2 clusters. The total potential energy of each system decreases after the hydrolysis of Zn(CH3COO)2, suggesting that it is a thermally favorable process in SCW. The OH- reaction product incorporates into the amorphous Zn(CH3COO)2 cluster and CH3COOH is in the SCW phase. Our results provide a general theoretical framework for the Zn(CH3COO)2 hydrothermal synthesis in SCW.

Key words: Zinc oxide, Zinc acetate, Supercritical water, Hydrothermal synthesis, Hydrolysis, Molecular dynamics simulation

MSC2000: 

  • O645