Antisolvent crystallization of aqueous ammonium dihydrogen phosphate solutions by addition of acetone at different rates

作者：Sangwal Keshra^*; Mielniczek Brzoska Ewa

来源：CRYSTAL RESEARCH AND TECHNOLOGY, 2016, 51(8): 475-490.

DOI：10.1002/crat.201600071

• antisolvent crystallization
• ammonium dihydrogen phosphate
• metastable zone width
• solution temperature

Results of an investigation of in situ measurements of laser-beam intensity I-s and I-m transmitted through aqueous ammonium dihydrogen phosphate (ADP) solutions saturated at 30 degrees C and water, respectively, and temperature T-s of solution and T-m of water during feeding of antisolvent acetone at different rates R-A, using an indigenously designed experimental setup, are presented and discussed. It was found that: (1) for the measurement of MSZW, defined as the maximum volume fraction of acetone content Delta x(max) in the solution, obtained from temperature measurements are more reliable than transmitted laser-beam intensity measurements for solutions, (2) two minima Delta T-min1 and Delta T-min2 associated with endothermic reactions, separated by a maximum Delta T-max due to exothermic reactions appear in the plots of temperature difference Delta T = T-s-T-m against acetone feeding time t, and (3) in the Delta T(t) plots there are time intervals Delta t of constant rates R-T of increase in Delta T of aqueous ADP solutions, and these values of R-T increase linearly with acetone feeding time rate RA. The experimental data on the observed dependence of MSZW on antisolvent feeding rate R-A, the appearance of minima Delta T-min1 and Delta T-min2 and maximum Delta T-max and their dependence on R-A, and the relationship between R-T and R-A are discussed from consideration of processes of nucleation and growth of crystallites.

• 出版日期2016-8