The batch cooling crystallization initiated from spontaneous nucleation for aqueous solution of potassium nitrate was studied. The concentration and transmittance data were acquired on line throughout the operation.Ba...The batch cooling crystallization initiated from spontaneous nucleation for aqueous solution of potassium nitrate was studied. The concentration and transmittance data were acquired on line throughout the operation.Based on solute mass transfer in both liquid and solid phases, a kinetic model was deduced by assuming that the late period of primary nucleation resembles the initial period of the secondary nucleation. Nucleation and crystal growth stages were identified. Kinetic parameters were estimated piecewise from online experimental data and compared with those in literature. The estimated kinetic parameters for stages without apparent primary nucleation agreed well with those in literature. Further, a simulated concentration curve was also drawn from the estimated kinetic parameters and it matched well with that in experiment.展开更多
The crystal of aconitine has been obtained through an unexpected spontaneous change of the solid power of aconitine in air and characterized by single-crystal X-ray diffraction analysis and elemental analysis. Crystal...The crystal of aconitine has been obtained through an unexpected spontaneous change of the solid power of aconitine in air and characterized by single-crystal X-ray diffraction analysis and elemental analysis. Crystallographic data： orthorhombic, space group P2_12_12_1 with a = 17.0745（6）, b = 15.5990（6）, c = 12.2443（6） ？, V = 3261.2（2） ？~3, Z = 4, C_（34）H_（47）NO_（11）, M_r = 645.73, D_c = 1.315 g/cm^3, F（000） = 1384, μ（MoKa） = 0.098 mm^（-1）, R = 0.0605 and wR = 0.1311. Aconitine is diester diterpenoid alkaloid, and its main structure is composed of four six-membered and two five-membered rings. The intramolecular and intermolecular O–H···O and C–H···O hydrogen bonds extend the adjacent molecules into a one-dimensional chain and a two-dimensional framework, which may be the essential reason for the change.展开更多
Non-superimposable mirror image crystals of both enantiomers（S/R） of cyclicγ-alkenyl alcohol（2） have been recognized and remarkably identified by the naked eye.More interestingly,both crystals are an outcome of m...Non-superimposable mirror image crystals of both enantiomers（S/R） of cyclicγ-alkenyl alcohol（2） have been recognized and remarkably identified by the naked eye.More interestingly,both crystals are an outcome of most astonishingly H-bond and intermolecularσ/π-πinteractions.They accounted for the relatively rare and less predictable spontaneous resolution with optical purity 〉99%ee from the racemic mixture.The chiral discrimination mechanism of this spontaneous resolution has also been proposed.展开更多
文摘The batch cooling crystallization initiated from spontaneous nucleation for aqueous solution of potassium nitrate was studied. The concentration and transmittance data were acquired on line throughout the operation.Based on solute mass transfer in both liquid and solid phases, a kinetic model was deduced by assuming that the late period of primary nucleation resembles the initial period of the secondary nucleation. Nucleation and crystal growth stages were identified. Kinetic parameters were estimated piecewise from online experimental data and compared with those in literature. The estimated kinetic parameters for stages without apparent primary nucleation agreed well with those in literature. Further, a simulated concentration curve was also drawn from the estimated kinetic parameters and it matched well with that in experiment.
基金Supported by the Scientific Research Project of Education Department of Shaanxi Provincial Government in 2014(No.14JK1045)the key project of Baoji University of Arts and Sciences in 2014(No.ZK14009)
文摘The crystal of aconitine has been obtained through an unexpected spontaneous change of the solid power of aconitine in air and characterized by single-crystal X-ray diffraction analysis and elemental analysis. Crystallographic data： orthorhombic, space group P2_12_12_1 with a = 17.0745（6）, b = 15.5990（6）, c = 12.2443（6） ？, V = 3261.2（2） ？~3, Z = 4, C_（34）H_（47）NO_（11）, M_r = 645.73, D_c = 1.315 g/cm^3, F（000） = 1384, μ（MoKa） = 0.098 mm^（-1）, R = 0.0605 and wR = 0.1311. Aconitine is diester diterpenoid alkaloid, and its main structure is composed of four six-membered and two five-membered rings. The intramolecular and intermolecular O–H···O and C–H···O hydrogen bonds extend the adjacent molecules into a one-dimensional chain and a two-dimensional framework, which may be the essential reason for the change.
基金Financial support from Beijing Institute of Technology(No. 2011CX01008 and others)partially from NSFC(No.20972016)Chinese Scholarship Council(M.Sohail)
文摘Non-superimposable mirror image crystals of both enantiomers（S/R） of cyclicγ-alkenyl alcohol（2） have been recognized and remarkably identified by the naked eye.More interestingly,both crystals are an outcome of most astonishingly H-bond and intermolecularσ/π-πinteractions.They accounted for the relatively rare and less predictable spontaneous resolution with optical purity 〉99%ee from the racemic mixture.The chiral discrimination mechanism of this spontaneous resolution has also been proposed.
