Insight into the experiment and extraction mechanism for separating carbazole from anthracene oil with quaternary ammonium-based deep eutectic solvents

Carbazole is an irreplaceable basic organic chemical raw material and intermediate in industry.The separation of carbazole from anthracene oil by environmental benign solvents is important but still a challenge in chemical engineering.Deep eutectic solvents (DESs) as a sustainable green separation solvent have been proposed for the separation of carbazole from model anthracene oil.In this research,three quaternary ammonium-based DESs were prepared using ethylene glycol (EG) as hydrogen bond donor and tetrabutylammonium chloride (TBAC),tetrabutylammonium bromide or choline chloride as hydrogen bond acceptors.To explore their extraction performance of carbazole,the conductor-like screening model for real solvents (COSMO-RS) model was used to predict the activity coefficient at infinite dilution (γ^(∞)) of carbazole in DESs,and the result indicated TBAC:EG (1:2) had the stronger extraction ability for carbazole due to the higher capacity at infinite dilution (C^(∞)) value.Then,the separation performance of these three DESs was evaluated by experiments,and the experimental results were in good agreement with the COSMO-RS prediction results.The TBAC:EG (1:2) was determined as the most promising solvent.Additionally,the extraction conditions of TBAC:EG (1:2) were optimized,and the extraction efficiency,distribution coefficient and selectivity of carbazole could reach up to 85.74%,30.18 and 66.10%,respectively.Moreover,the TBAC:EG (1:2) could be recycled by using environmentally friendly water as antisolvent.In addition,the separation performance of TBAC:EG (1:2) was also evaluated by real crude anthracene,the carbazole was obtained with purity and yield of 85.32%,60.27%,respectively.Lastly,the extraction mechanism was elucidated byσ-profiles and interaction energy analysis.Theoretical calculation results showed that the main driving force for the extraction process was the hydrogen bonding ((N–H...Cl) and van der Waals interactions (C–H...O and C–H...π),which corresponding to the blue and green isosurfaces in IGMH analysis.This work presented a novel method for separating carbazole from crude anthracene oil,and will provide an important reference for the separation of other high value-added products from coal tar.

Synergistic CO_(2) mineralization using coal fly ash and red mud as a composite system

CO_(2) mineralization plays a critical role in the storage and utilization of CO_(2).Coal fly ash(CFA)and red mud(RM)are widely utilized as CO_(2) mineralizers.However,the inert calcium species in CFA limit its carbonation capacity,meanwhile the substantial Ca^(2+)releasing of RM is hindered by a covering layer of calcium carbonate.In this study,CO_(2) mineralization in a composite system of CFA and RM was investigated to enhance the carbonation capacity.Multiple analyzers were employed to characterize the raw materials and resulting mineralization products.The results demonstrated that a synergistic effect existed in the composite system of CFA and RM,resulting in improving CO_(2) mineralization rate and efficiency.The produced calcium carbonate was ectopically attached the surface of CFA in the composite system,thus slowing down its coverage on the surface of RM.This phenomenon facilitated further releasing Ca^(2+)from the internal RM,thereby enhancing CO_(2) mineralization efficiency.Meanwhile,the inclusion of RM significantly improved the alkalinity of the composite system,which not only promoted the dissolution of Ca^(2+)of the inert CaSO_(4)(H_(2)O)_(2) in CFA,but also accelerated CO_(2) mineralization rate.The investigation would be beneficial to CO_(2) mineralization using industrial solid wastes.

Hot deformation behavior and processing map of Mg-2Zn-1Al-0.2RE alloy

In this study,uniaxial hot compression tests were carried out between 200 and 400℃ over strain rates of0.001-1 s-1 to investigate the hot deformation behavior of Mg-2 Zn-1 Al-0.2 RE alloy with coarse grains.The average activation energy was measured to be 174.51 kJ/mol.In addition,a constitutive relation based on the Arrhenius equation was established.Dynamic recrystallization(DRX) kinetics were studied by Avrami equation to characterize the evolution of DRX volume fraction.DRX was favored at high temperatures of 300-400℃ and low strain rates of 0.001-0.01 s-1.According to dynamic material model and Prasad’s instability criterion,a maximum power dissipation of 38% and 32% occurs at 400℃/0.001 s-1 and 400℃/0.01 s-1,respectively.According to the proce ssing map,330-400℃/0.001-0.01 s-1was determined as the optimum deformation parameter range.

Application of dynamic recrystallization model in AZ12 magnesium alloy rolling process

To deeply understand the dynamic recrystallization behavior of as-cast AZ12 magnesium alloy in deformation process,the uniaxial hot compression experiments were implemented through systematic isothermal compression experiments.The true strain of thermal compression experiments was set to 50%with temperatures of 200,250,300,350,400℃and the strain rates of 0.001,0.01,0.1,1 s^(-1).The Dynamic Recrystallization(DRX)kinetic model of AZ12 magnesium alloy was established and the accuracy of this model was verified.The model is used to predict the volume fraction of the sheet obtained by rolling through different rolling passes under the condition of consistent total reduction(50%).And the predicted results are in good agreement with the experimental results.