Optimization of solvent crystallization process in obtaining high purity anthracene and carbazole from crude anthracene

Abstract

Solvent crystallization is the main method used for preparing anthracene and carbazole from the crude anthracene. The key to the optimization of this method is improving the solubility selectivity of the solvent by means of solvent modulating and process optimization. In this study, the solubility of anthracene, phenanthrene, and carbazole in xylene, dimethylformamide (DMF), DMF with amine/amide, isopropanolamine, and chlorobenzene is examined and the solid‐liquid ternary anthracene–carbazole–DMF/(DMF+19.96% isopropanolamine) system phase diagram is determined and applied in the solvent crystallization process. The results showed that the solubility selectivity of xylene increases with increased temperature. Also, selectivity increases with an increase of the amount of isopropanolamine in the mixture of DMF and isopropanolamine, while decreases with increased temperature. Through multiple washings of crude anthracene with xylene, DMF+19.96% isopropanolamine, and chlorobenzene, it was possible to obtain anthracene and carbazole of purity higher than 98 wt %. © 2013 American Institute of Chemical Engineers AIChE J, 60: 275–281, 2014

Solvent Polarity of Cyclic Ketone (Cyclopentanone, Cyclohexanone): Alcohol (Methanol, Ethanol) Renewable Mixed-Solvent Systems for Applications in Pharmaceutical and Chemical Processing

“…KT parameters are used in the first step to identify new potential solvents . According to the expected KT parameters of HBD–HBA solvent-pairs, many solvent mixtures can be used to develop green chemical processes with supercritical fluids and to replace toxic dipolar aprotic solvents (e.g., N -methyl-2-pyrrolidone and N,N -dimethylformamide) being used in the processing of active pharmaceutical ingredient (API), , polymers, and biomass. , Mixed-solvents can also be used in chemical processing to aid in selective separations. , The solubility of anthracene in a methanol–cyclohexanone mixture (HBD–HBA) is close to that in a dipolar aprotic solvent, and the selectivity of the solvent mixture can probably be controlled.…”

“…16,17 Mixedsolvents can also be used in chemical processing to aid in selective separations. 18,19 The solubility of anthracene in a methanol−cyclohexanone mixture (HBD−HBA) 20 that in a dipolar aprotic solvent, 21 and the selectivity of the solvent mixture can probably be controlled. Solvent polarities of pure liquids can be predicted using quantitative structure−property relationships; 22 however, such methods are not applicable to mixed-solvent systems since formation of complex molecules (1−2) occurs and there can be preferential solvation of the solvatochromic indicator.…”

Natural Borneol Recycling from <i>Cinnamomum camphor</i> chvar. <i>Borneol</i> Oil Residue by Fractional Distillation and Recrystallization

“…Solvent amount is another factor affecting recrystallization efficiency [15]. As showed in Table 2, the content of natural borneol increased from 85.9 ± 0.8 % to 94.3 ± 0.6 %, with respect to the n-hexane ratio of 1.2 to 2.2.…”

Highly Efficient Solvent Screening for Separating Carbazole from Crude Anthracene

“…In addition, when the volume percentage of isopropanolamine exceeded 40%, the content of anthracene in refined anthracene decreased gradually from 90.19 wt % by DMF + 50% isopropanolamine to 81.28 wt % by DMF + 90% isopropanolamine and the carbazole impurity increased to 15.87 wt %. The selectivity of the mixed solvent improved with the volume percentage of isopropanolamine . Isopropanolamine has high selectivity for carbazole; however, the viscosity is too high (20 °C and 31 mPa s) for mass transfer and filtration in the crystallization process.…”