Melt crystallization of 2,4-dinitrochlorobenzene: Purification and process parameters evaluation

Jia, Shengzhe; Jing, Bo; Gao, Zhenguo; Gong, Junbo; Wang, Jingkang; Rohani, Sohrab

doi:10.1016/j.seppur.2020.118140

Cited by 23 publications

(17 citation statements)

References 31 publications

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“…The driving force of crystallization is the heat and mass transfer, and the transfer rate increases with the cooling rate. 41 Therefore, the increase of the cooling rate led to the rapid growth of crystals. The crystal growth is a typically dendritic growth, the rate of which is too fast that leading to the imperfect crystal growth.…”

Section: Resultsmentioning

confidence: 99%

Purification of MDI Isomers Using Dynamic Falling Film Melt Crystallization: Experiment and Molecular Simulation

Lian

Wang

et al. 2022

ACS Omega

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In this work, the isomer mixture of 4,4′-diphenylmethane diisocyanate (MDI) and 2,4′-MDI was separated and purified by dynamic falling film melt crystallization, and 99.3% purity and 50.8% yield of 4,4′-MDI could be obtained under optimized conditions. The separation mechanism was simulated by density functional theory (DFT) and molecular dynamics (MD) simulation. Results showed that compared with 2,4′-MDI, 4,4′-MDI molecules could form a more stable and symmetrical crystal structure due to their stronger charge density symmetry and electrostatic potential energy. Furthermore, the separation phenomenon and the formation of the crystal structure were observed according to the radial distribution function (RDF) and orientation correlation function obtained from MD simulation. Finally, the attachment energy (AE) model was used to observe and compare different crystal surfaces; it was proposed that the aggregation of 4,4′-MDI was attributed to the polar attraction between isocyanate groups according to the results of the orientation correlation function. It was also observed that compared with 2,4′-MDI, 4,4′-MDI molecules on the (110) crystal surface were easier to form crystal structures.

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Section: Resultsmentioning

confidence: 99%

Purification of MDI Isomers Using Dynamic Falling Film Melt Crystallization: Experiment and Molecular Simulation

Lian

Wang

et al. 2022

ACS Omega

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“…During the growth of the crystal layer, it is easy to entrain impurities. The purity and purification yield are affected by different operating parameters. , Therefore, it is very important to select the appropriate operating parameters for the crystallization process. The effects of different operating parameters on the yield and purity of 2-P were systemically studied by a single-factor experiment in this work.…”

Section: Resultsmentioning

confidence: 99%

Purification of 2-Pyrrolidone by Falling Film Melt Crystallization

Chen

2021

Ind. Eng. Chem. Res.

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Industrial grade 2-pyrrolidone with a purity of 99.5% is produced by aminolysis of γ-butyrolactone and subsequent fractional distillation, but it still contains trace amounts of γ-butyrolactone and other impurities. Falling film melt crystallization was applied for further purification of 2-pyrrolidone from 99.5% to a very high purity. The effects of the precooling temperature, feed rate, cooling rate, final crystallization temperature, heating rate, and final sweating temperature on the purity and yield of 2-pyrrolidone were studied. 2-Pyrrolidone was purified by falling film melt crystallization to a purity and yield of more than 99.9 and 73.3%, respectively. The mathematical model of falling film crystallization was applied for simulation of the crystal layer growth of 2-pyrrolidone. The simulated average thickness of the crystal layer was in good agreement with the experimental values, demonstrating the applicability of the model to falling film crystallization of 2-pyrrolidone.

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“…Generally, crystallization plays an essential role in crystal nucleation and growth, which is closely related to the purification efficiency. 12,53 However, challenges remain in the melt crystallization process, including i) extremely high supercooling is needed to induce the primary crystal. ii) The initial crystal formed deposits at the bottom of the tube, causing poor crystal packing and pore structure.…”

Section: Process Intensification Approachesmentioning

confidence: 99%

“…Therefore, sweating operation is introduced as a crucial approach to separate the mixtures and purify the products. Isomeric system separation and purification is often achieved by melt crystallization, such as o -, m -, and p -cresol, 169 durene isomers, 40 isomeric aldehydes, 22,41 dinitrochlorobenzene isomers, 53 p -, o -chlorobromobenzene isomers, 12 2,4-, 2,6-dinitrochlorobenzene, 7,53 etc. Melt crystallization is also widely applied in water treatment by considering the freezing process.…”

Section: Applications In Melt Crystallizationmentioning

confidence: 99%

Recent advances in melt crystallization, towards process intensification and technique development

Li-xia

Dang

2022

CrystEngComm

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Melt crystallization of 2,4-dinitrochlorobenzene: Purification and process parameters evaluation

Cited by 23 publications

References 31 publications

Purification of MDI Isomers Using Dynamic Falling Film Melt Crystallization: Experiment and Molecular Simulation

Purification of MDI Isomers Using Dynamic Falling Film Melt Crystallization: Experiment and Molecular Simulation

Purification of 2-Pyrrolidone by Falling Film Melt Crystallization

Recent advances in melt crystallization, towards process intensification and technique development

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