TY - JOUR
T1 - Solid Forms, Crystal Habits, and Solubility of Danthron
AU - Cheuk, Dominic
AU - Khamar, Dikshitkumar
AU - McArdle, Patrick
AU - Rasmuson, Åke C.
N1 - Publisher Copyright:
© 2015 American Chemical Society.
PY - 2015/7/9
Y1 - 2015/7/9
N2 - The polymorphism, crystal habits, and solubility of 1,8-dihydroxyanthraquinone (danthron) were investigated in acetic acid, acetone, acetonitrile, n-butanol, and toluene. The solubility was determined for the commercially available form (FI) from 293.15 K to 318.15 K by the gravimetric method. The influence of solvents on crystal habit and polymorphic form has been investigated. Three different crystal habits of danthron were obtained from slow evaporation and cooling experiments. By evaporation, thin squares of FI were obtained from n-butanol and toluene solutions while both FI and fine needles of FII were obtained from acetone and acetonitrile solutions. In addition, needle-shaped solvate crystals were obtained from acetic acid solutions and the structure of the solvate was solved by single crystal X-ray diffraction. From cooling crystallization experiments, mixtures of FI and FII were often obtained from various solvents, but FI and FII possess distinct habits which can be easily distinguished by visual comparison. Slurry conversion experiments have established that FI is the thermodynamically stable polymorph of danthron at ambient conditions. Differntial scanning calorimetry (DSC) and high-temperature powder X-ray diffraction (PXRD) have shown that both FI and FII will transform into a high-temperature form (FIV) around 435 K to 439 K before this form melts at 468.5 K. FI, FII, and FIV have been characterized by transmission and high-temperature PXRD, scanning electron microscopy, infrared spectrometry, Raman spectrometry, thermogravimetric analysis, and DSC. The solubility of danthron FI in the pure organic solvents of the present work and in the temperature range investigated is below 4.3 % by weight and decreases in the order toluene, acetone, acetonitrile, and n-butanol.
AB - The polymorphism, crystal habits, and solubility of 1,8-dihydroxyanthraquinone (danthron) were investigated in acetic acid, acetone, acetonitrile, n-butanol, and toluene. The solubility was determined for the commercially available form (FI) from 293.15 K to 318.15 K by the gravimetric method. The influence of solvents on crystal habit and polymorphic form has been investigated. Three different crystal habits of danthron were obtained from slow evaporation and cooling experiments. By evaporation, thin squares of FI were obtained from n-butanol and toluene solutions while both FI and fine needles of FII were obtained from acetone and acetonitrile solutions. In addition, needle-shaped solvate crystals were obtained from acetic acid solutions and the structure of the solvate was solved by single crystal X-ray diffraction. From cooling crystallization experiments, mixtures of FI and FII were often obtained from various solvents, but FI and FII possess distinct habits which can be easily distinguished by visual comparison. Slurry conversion experiments have established that FI is the thermodynamically stable polymorph of danthron at ambient conditions. Differntial scanning calorimetry (DSC) and high-temperature powder X-ray diffraction (PXRD) have shown that both FI and FII will transform into a high-temperature form (FIV) around 435 K to 439 K before this form melts at 468.5 K. FI, FII, and FIV have been characterized by transmission and high-temperature PXRD, scanning electron microscopy, infrared spectrometry, Raman spectrometry, thermogravimetric analysis, and DSC. The solubility of danthron FI in the pure organic solvents of the present work and in the temperature range investigated is below 4.3 % by weight and decreases in the order toluene, acetone, acetonitrile, and n-butanol.
UR - http://www.scopus.com/inward/record.url?scp=84937501252&partnerID=8YFLogxK
U2 - 10.1021/acs.jced.5b00192
DO - 10.1021/acs.jced.5b00192
M3 - Article
AN - SCOPUS:84937501252
SN - 0021-9568
VL - 60
SP - 2110
EP - 2118
JO - Journal of Chemical and Engineering Data
JF - Journal of Chemical and Engineering Data
IS - 7
ER -