Special Issue "Advances in Industrial Crystallization"

A special issue of Crystals (ISSN 2073-4352). This special issue belongs to the section "Industrial Crystallization".

Deadline for manuscript submissions: closed (30 June 2020).

Special Issue Editors

Prof. Dr. Heike Lorenz
Website
Guest Editor
Max Planck Institute for Dynamics of Complex Technical Systems, Sandtorstrasse 1, 39106 Magdeburg, Germany
Interests: phase equilibria; crystallization kinetics; process monitoring & design; separation of fine chemicals, large scale industrial products and renewable resources; innovative crystallization-based separation concepts; enantiomers; natural products; multi-component mixtures
Dr. Erik Temmel

Guest Editor
DSM Nutritional Products AG, Sisseln, Switzerland" to "Sulzer Chemtech Ltd, Basel, Switzerland
Interests: phase equilibria; crystallization kinetics; continuous crystallization; process monitoring; process design; applied population balance and process modelling; process intensification and combination; process optimization; novel measurement techniques

Special Issue Information

Dear Colleagues,

Crystallization is a key technology utilized in many industries for the manufacture of bulk and fine chemicals, such as agrochemicals, pharmaceutical ingredients and food components. There, the objectives of applying crystallization processes are usually twofold: separation and purification of substances on the one hand and, targeted product design on the other hand. The latter refers to the generation of product particles of desired properties, as purity, a particular solid-state form, crystal size (distribution) or morphology. Process-related target variables include, amongst others, yield, productivity, robustness and costs. The overall process, thus, has to fulfill multiple tasks at same time.

According to the industrial importance and wide application field of crystallization, active research is performed on a broad range of subjects covering fundamentals (e.g. phase equilibria, kinetics and crystallography), analytical tools for crystallization monitoring, separation process design and optimization, product development and, addresses integrated process chains and sustainability issues as well. Considering these variety of potential topics, the scope of this Special Issue on “Advances in Industrial Crystallization” is intentionally broad. We invite interdisciplinary contributions concerning both, understanding crystallization processes and crystallization behavior of compounds, and their applications in commodities and fine chemicals industries and sustainability fields.

Some keywords are given as a guide for submissions to this Special Issue, but research papers dealing with other innovative findings in industrial crystallization are also welcome.

Prof. Heike Lorenz
Dr. Erik Temmel
Guest Editors

Manuscript Submission Information

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Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Crystals is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 1600 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • Phase equilibria
  • Measurement of crystallization kinetics
  • Crystallization process monitoring
  • Advances in process and product design
  • Industrial applications
  • Separation of complex mixtures
  • Innovative crystallization process concepts and combinations

Published Papers (12 papers)

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Research

Open AccessArticle
The Steps from Batchwise to Continuous Crystallization for a Fine Chemical: A Case Study
Crystals 2020, 10(6), 542; https://doi.org/10.3390/cryst10060542 - 24 Jun 2020
Abstract
Many processes to produce fine chemicals and precursors of pharmaceuticals are still operated in batchwise mode. However, recently, more producers have taken a change to continuous operation mode into consideration, performing studies and trials on such a change, while some have even already [...] Read more.
Many processes to produce fine chemicals and precursors of pharmaceuticals are still operated in batchwise mode. However, recently, more producers have taken a change to continuous operation mode into consideration, performing studies and trials on such a change, while some have even already exchanged their production mode from batchwise to continuous operation. In this paper, the stepwise development from an initial idea to industrial implementation via laboratory testing and confirmation is revealed through the example of an organic fine chemical from the perspective of a crystallization plant manufacturer. We begin with the definition of the objectives of the project and a brief explanation of the advantages of continuous operation and the associated product properties. The results of the laboratory tests, confirming the assumptions made upfront, are reported and discussed. Finally, the implementation of an industrial plant using a draft tube baffled (DTB) crystallizer and the final product properties are shown. Product properties such as crystal size distribution, crystal shape, related storage stability and flowability have successfully been improved. Full article
(This article belongs to the Special Issue Advances in Industrial Crystallization)
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Open AccessArticle
Systematic Investigations on Continuous Fluidized Bed Crystallization for Chiral Separation
Crystals 2020, 10(5), 394; https://doi.org/10.3390/cryst10050394 - 14 May 2020
Abstract
A recently developed continuous enantioseparation process utilizing two coupled fluidized bed crystallizers is systematically investigated to identify essential correlations between different operation parameters and the corresponding process performance on the example of asparagine monohydrate. Based on liquid phase composition and product crystal size [...] Read more.
A recently developed continuous enantioseparation process utilizing two coupled fluidized bed crystallizers is systematically investigated to identify essential correlations between different operation parameters and the corresponding process performance on the example of asparagine monohydrate. Based on liquid phase composition and product crystal size distribution data, it is proven that steady state operation is achieved reproducibly in a relatively short time. The process outputs at steady state are compared for different feed flow rates, supersaturations, and crystallization temperatures. It is shown that purities >97% are achieved with productivities up to 40 g/L/h. The size distribution, which depends almost exclusively on the liquid flow rate, can be easily adjusted between 260 and 330 µm (mean size) with an almost constant standard deviation of ±55 µm. Full article
(This article belongs to the Special Issue Advances in Industrial Crystallization)
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Open AccessArticle
Concept Study for an Integrated Reactor-Crystallizer Process for the Continuous Biocatalytic Synthesis of (S)-1-(3-Methoxyphenyl)ethylamine
Crystals 2020, 10(5), 345; https://doi.org/10.3390/cryst10050345 - 27 Apr 2020
Abstract
An integrated biocatalysis-crystallization concept was developed for the continuous amine transaminase-catalyzed synthesis of (S)-1-(3-methoxyphenyl)ethylamine, which is a valuable intermediate for the synthesis of rivastigmine, a highly potent drug for the treatment of early stage Alzheimer’s disease. The three-part vessel system developed [...] Read more.
An integrated biocatalysis-crystallization concept was developed for the continuous amine transaminase-catalyzed synthesis of (S)-1-(3-methoxyphenyl)ethylamine, which is a valuable intermediate for the synthesis of rivastigmine, a highly potent drug for the treatment of early stage Alzheimer’s disease. The three-part vessel system developed for this purpose consists of a membrane reactor for the continuous synthesis of the product amine, a saturator vessel for the continuous supply of the amine donor isopropylammonium and the precipitating reagent 3,3-diphenylpropionate and a crystallizer in which the product amine can continuously precipitate as (S)-1-(3-methoxyphenyl)ethylammonium-3,3-diphenylpropionate. Full article
(This article belongs to the Special Issue Advances in Industrial Crystallization)
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Open AccessArticle
Solvent Effects on Catechol Crystal Habits and Aspect Ratios: A Combination of Experiments and Molecular Dynamics Simulation Study
Crystals 2020, 10(4), 316; https://doi.org/10.3390/cryst10040316 - 18 Apr 2020
Abstract
This work could help to better understand the solvent effects on crystal habits and aspect ratio changes at the molecular level, which provide some guidance for solvent selection in industrial crystallization processes. With the catechol crystal habits acquired using both experimental and simulation [...] Read more.
This work could help to better understand the solvent effects on crystal habits and aspect ratio changes at the molecular level, which provide some guidance for solvent selection in industrial crystallization processes. With the catechol crystal habits acquired using both experimental and simulation methods in isopropanol, methyl acetate and ethyl acetate, solvent effects on crystal morphology were explored based on the modified attachment energy model. Firstly, morphologically dominant crystal faces were obtained with the predicted crystal habit in vacuum. Then, modified attachment energies were calculated by the molecular dynamics simulation to modify the crystal shapes in a real solvent environment, and the simulation results were in agreement with the experimental ones. Meanwhile, the surface properties such as roughness and the diffusion coefficient were introduced to analyze the solvent adsorption behaviors and the radial distribution function curves were generated to distinguish diverse types of interactions like hydrogen bonds and van der Waals forces. Results show that the catechol crystal habits were affected by the combination of the attachment energy, surface structures and molecular interaction types. Moreover, the changing aspect ratios of catechol crystals are closely related to the existence of hydrogen bonds which contribute to growth inhibition on specific faces. Full article
(This article belongs to the Special Issue Advances in Industrial Crystallization)
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Open AccessArticle
Gypsum Crystallization during Reverse Osmosis Desalination of Water with High Sulfate Content in Presence of a Novel Fluorescent-Tagged Polyacrylate
Crystals 2020, 10(4), 309; https://doi.org/10.3390/cryst10040309 - 16 Apr 2020
Abstract
Gypsum scaling in reverse osmosis (RO) desalination process is studied in presence of a novel fluorescent 1,8-naphthalimide-tagged polyacrylate (PAA-F1) by fluorescent microscopy, scanning electron microscopy (SEM), dynamic light scattering (DLS) and a particle counter technique. A comparison of PAA-F1 with a previously reported [...] Read more.
Gypsum scaling in reverse osmosis (RO) desalination process is studied in presence of a novel fluorescent 1,8-naphthalimide-tagged polyacrylate (PAA-F1) by fluorescent microscopy, scanning electron microscopy (SEM), dynamic light scattering (DLS) and a particle counter technique. A comparison of PAA-F1 with a previously reported fluorescent bisphosphonate HEDP-F revealed a better PAA-F1 efficacy, and a similar behavior of polyacrylate and bisphosphonate inhibitors under the same RO experimental conditions. Despite expectations, PAA-F1 does not interact with gypsum. For both reagents, it is found that scaling takes place in the bulk retentate phase via heterogeneous nucleation step. The background “nanodust” plays a key role as a gypsum nucleation center. Contrary to popular belief, an antiscalant interacts with “nanodust” particles, isolating them from calcium and sulfate ions sorption. Therefore, the number of gypsum nucleation centers is reduced, and in turn, the overall scaling rate is diminished. It is also shown that, the scale formation scenario changes from the bulk medium, in the beginning, to the sediment crystals growth on the membrane surface, at the end of the desalination process. It is demonstrated that the fluorescent-tagged antiscalants may become very powerful tools in membrane scaling inhibition studies. Full article
(This article belongs to the Special Issue Advances in Industrial Crystallization)
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Open AccessFeature PaperArticle
Purification of Curcumin from Ternary Extract-Similar Mixtures of Curcuminoids in a Single Crystallization Step
Crystals 2020, 10(3), 206; https://doi.org/10.3390/cryst10030206 - 16 Mar 2020
Cited by 1
Abstract
Crystallization-based separation of curcumin from ternary mixtures of curcuminoids having compositions comparable to commercial extracts was studied experimentally. Based on solubility and supersolubility data of both, pure curcumin and curcumin in presence of the two major impurities demethoxycurcumin (DMC) and bis(demethoxy)curcumin (BDMC), seeded [...] Read more.
Crystallization-based separation of curcumin from ternary mixtures of curcuminoids having compositions comparable to commercial extracts was studied experimentally. Based on solubility and supersolubility data of both, pure curcumin and curcumin in presence of the two major impurities demethoxycurcumin (DMC) and bis(demethoxy)curcumin (BDMC), seeded cooling crystallization procedures were derived using acetone, acetonitrile and 50/50 (wt/wt) mixtures of acetone/2-propanol and acetone/acetonitrile as solvents. Starting from initial curcumin contents of 67–75% in the curcuminoid mixtures single step crystallization processes provided crystalline curcumin free of BDMC at residual DMC contents of 0.6–9.9%. Curcumin at highest purity of 99.4% was obtained from a 50/50 (wt/wt) acetone/2-propanol solution in a single crystallization step. It is demonstrated that the total product yield can be significantly enhanced via addition of water, 2-propanol and acetonitrile as anti-solvents at the end of a cooling crystallization process. Full article
(This article belongs to the Special Issue Advances in Industrial Crystallization)
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Open AccessArticle
TiO2-Seeded Hydrothermal Growth of Spherical BaTiO3 Nanocrystals for Capacitor Energy-Storage Application
Crystals 2020, 10(3), 202; https://doi.org/10.3390/cryst10030202 - 14 Mar 2020
Abstract
Simple but robust growth of spherical BaTiO3 nanoparticles with uniform nanoscale sizes is of great significance for the miniaturization of BaTiO3-based electron devices. This paper reports a TiO2-seeded hydrothermal process to synthesize spherical BaTiO3 nanoparticles with a [...] Read more.
Simple but robust growth of spherical BaTiO3 nanoparticles with uniform nanoscale sizes is of great significance for the miniaturization of BaTiO3-based electron devices. This paper reports a TiO2-seeded hydrothermal process to synthesize spherical BaTiO3 nanoparticles with a size range of 90–100 nm using TiO2 (Degussa) and Ba(NO3)2 as the starting materials under an alkaline (NaOH) condition. Under the optimum conditions ([NaOH] = 2.0 mol L−1, RBa/Ti = 2.0, T = 210 °C and t = 8 h), the spherical BaTiO3 nanoparticles obtained exhibit a narrow size range of 91 ± 14 nm, and the corresponding BaTiO3/polymer/Al film is of a high dielectric constant of 59, a high break strength of 102 kV mm−1, and a low dielectric loss of 0.008. The TiO2-seeded hydrothermal growth has been proved to be an efficient process to synthesize spherical BaTiO3 nanoparticles for potential capacitor energy-storage applications. Full article
(This article belongs to the Special Issue Advances in Industrial Crystallization)
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Open AccessArticle
Stereoselective Crystallization of Chiral 3,4-Dimethylphenyl Glycerol Ether Complicated by Plurality of Crystalline Modifications
Crystals 2020, 10(3), 201; https://doi.org/10.3390/cryst10030201 - 14 Mar 2020
Abstract
Spontaneous resolution of Pasteur’s salt was historically the first way to obtain pure enantiomers from the racemate. The current increase in interest in the direct racemates resolution during crystallization is largely due to the opened prospects for the industrial application of this approach. [...] Read more.
Spontaneous resolution of Pasteur’s salt was historically the first way to obtain pure enantiomers from the racemate. The current increase in interest in the direct racemates resolution during crystallization is largely due to the opened prospects for the industrial application of this approach. The chiral 3-(3,4-dimethylphenoxy) propane-1,2-diol 1 is a synthetic precursor of practically useful amino alcohols, the enantiomers of which exhibit different biological effects. In this work, it was first discovered that racemic diol 1 is prone to spontaneous resolution. However, the crystallization process is complicated by the existence, along with the conglomerate, of two other crystalline forms. Using the differential scanning calorimetry (DSC) approach, methods have been developed to obtain individual metastable phases, and all identified modifications ((R)-1, (R+S)-1, α-rac-1, β-rac-1) were ranked by energy. The IR spectroscopy and powder X-ray diffraction (PXRD) methods demonstrated the identity of the first two forms and their proximity to the third, while β-rac-1 is significantly different from the rest. The crystal structure of the forms (R)-1 and α-rac-1 was established by the single crystal X-ray diffraction (SC-XRD) method. Preliminary information on the structure of β-rac-1 phase was obtained by the PXRD approach. Based on the information received, the experimental conditions for a successful direct resolution of racemic 1 into individual enantiomers by a preferential crystallization procedure were selected. Full article
(This article belongs to the Special Issue Advances in Industrial Crystallization)
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Open AccessArticle
Impact of the Surface Properties of Cellulose Nanocrystals on the Crystallization Kinetics of Poly(Butylene Succinate)
Crystals 2020, 10(3), 196; https://doi.org/10.3390/cryst10030196 - 13 Mar 2020
Abstract
The hydrophilicity of cellulose nanocrystals (CNCs) is a major challenge for their processing with hydrophobic polymers and matrices. As a result, many surface modifications have been proposed to hydrophobize CNCs. The authors showed in an earlier study that grafting alcohols of different chain [...] Read more.
The hydrophilicity of cellulose nanocrystals (CNCs) is a major challenge for their processing with hydrophobic polymers and matrices. As a result, many surface modifications have been proposed to hydrophobize CNCs. The authors showed in an earlier study that grafting alcohols of different chain lengths onto the surface of CNCs using toluene diisocyanate (TDI) as a linker can systematically hydrophobize CNCs to a water contact angle of up to 120° depending on the alcohol chain length. Then, the hydrophobized CNCs were used to mechanically reinforce poly(butylene succinate) (PBS), which is a hydrophobic polymer. As a result of hydrophobization, PBS/CNCs interfacial adhesion and the composite mechanical properties significantly improved with the increasing CNC contact angle. Continuing on these results, this paper investigates the impact of CNC surface properties on the crystallization behavior of PBS using differential scanning calorimetry (DSC). The results showed that the crystallization temperature of PBS increased from 74.7 °C to up to 86.6 °C as a result of CNC nucleation activity, and its value was proportionally dependent on the contact angle of the CNCs. In agreement, the nucleation activity factor (φ) estimated using Dobreva and Gutzow’s method decreased with the increasing CNC contact angle. Despite the nucleation action of CNCs, the rate constant of PBS crystallization as estimated using the Avrami model decreased in general as a result of a prevailing impeding effect. This decrease was minimized with increasing the contact angle of the CNCs. The impeding effect also increased the average activation energy of crystallization, which was estimated using the Kissinger method. Moreover, the Avrami exponent (n) decreased because of CNC addition, implying a heterogeneous crystallization, which was also apparent in the crystallization thermograms. Overall, the CNC addition facilitated PBS nucleation but retarded its crystallization, and both processes were significantly affected by the surface properties of the CNCs. Full article
(This article belongs to the Special Issue Advances in Industrial Crystallization)
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Open AccessArticle
Freeze Concentration of Aqueous [DBNH][OAc] Ionic Liquid Solution
Crystals 2020, 10(3), 147; https://doi.org/10.3390/cryst10030147 - 26 Feb 2020
Abstract
In the present work, freeze crystallization studies, as a novel concentration method for aqueous 1,5-diazabicyclo[4.3.0]non-5-enium acetate ([DBNH][OAc]) ionic liquid solution, were conducted. In order to find the appropriate temperature and composition range for freeze crystallization, the solid–liquid equilibrium of a binary [DBNH][OAc]–water compound [...] Read more.
In the present work, freeze crystallization studies, as a novel concentration method for aqueous 1,5-diazabicyclo[4.3.0]non-5-enium acetate ([DBNH][OAc]) ionic liquid solution, were conducted. In order to find the appropriate temperature and composition range for freeze crystallization, the solid–liquid equilibrium of a binary [DBNH][OAc]–water compound system was investigated with differential scanning calorimetry (DSC). Results of this analysis showed that the melting temperature of the pure ionic liquid was 58 ℃, whereas the eutectic temperature of the binary compound system was found to be −73 ℃. The activity coefficient of water was determined based on the freezing point depression data obtained in this study. In this study, the lowest freezing point was −1.28 ℃ for the aqueous 6 wt.% [DBNH][OAc] solution. Ice crystal yield and distribution coefficient were obtained for two types of aqueous solutions (3 wt.% and 6 wt.% [DBNH][OAc]), and two freezing times (40 min and 60 min) were used as the main parameters to compare the two melt crystallization methods: static layer freeze and suspension freeze crystallization. Single-step suspension freeze crystallization resulted in higher ice crystal yields and higher ice purities when compared with the single-step static layer freeze crystallization. The distribution coefficient values obtained showed that the impurity ratios in ice and in the initial solution for suspension freeze crystallization were between 0.11 and 0.36, whereas for static layer freeze crystallization these were between 0.28 and 0.46. Consequently, suspension freeze crystallization is a more efficient low-energy separation method than layer freeze crystallization for the aqueous-ionic liquid solutions studied and, therefore, this technique can be applied as a concentration method for aqueous-ionic liquid solutions. Full article
(This article belongs to the Special Issue Advances in Industrial Crystallization)
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Open AccessArticle
Numerical Model Study of Multiple Dendrite Motion Behavior in Melt Based on LBM-CA Method
Crystals 2020, 10(2), 70; https://doi.org/10.3390/cryst10020070 - 27 Jan 2020
Abstract
In this paper, a new method is proposed to solve the solute field of moving grains, and a Cellular automaton (CA)-Lattice Boltzmann method (LBM)-Semi rebound format(Ladd) coupling model which can accurately simulate the motion behavior of multiple dendrites is established. The growth process [...] Read more.
In this paper, a new method is proposed to solve the solute field of moving grains, and a Cellular automaton (CA)-Lattice Boltzmann method (LBM)-Semi rebound format(Ladd) coupling model which can accurately simulate the motion behavior of multiple dendrites is established. The growth process of microstructure in the solidification process of Al-4.7% Cu alloy ingot was calculated by Cellular automaton (CA) method, the momentum, heat, and mass transfer processes were calculated by Lattice Boltzmann method (LBM), and the melt-dendrite sharp interface interaction was treated by Ladd method. The reliability of the model is verified, and then the growth and movement of single dendrite and multiple dendrites under the action of gravity field are simulated. The simulation results show that the growth and movement mode of multiple dendrites are quite different from that of single dendrite, which is shown in two aspects: (1) the original motion state of dendrites is changed by the combination of flow field, which slows down the falling speed of dendrites to a certain extent; (2) the fusion of solute field between dendrites changed the original growth mode of boundary dendrites and increased their rotation speed. Full article
(This article belongs to the Special Issue Advances in Industrial Crystallization)
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Open AccessArticle
Effects of Synthesis Parameters on Crystallization Behavior of K-MER Zeolite and Its Morphological Properties on Catalytic Cyanoethylation Reaction
Crystals 2020, 10(2), 64; https://doi.org/10.3390/cryst10020064 - 23 Jan 2020
Cited by 1
Abstract
MER-type zeolite is an interesting microporous material that has been widely used in catalysis and separation. By carefully controlling the synthesis parameters, a procedure to synthesize K-MER zeolite crystals with various morphologies has been developed. The silica, water and mineralizer content in the [...] Read more.
MER-type zeolite is an interesting microporous material that has been widely used in catalysis and separation. By carefully controlling the synthesis parameters, a procedure to synthesize K-MER zeolite crystals with various morphologies has been developed. The silica, water and mineralizer content in the synthesis gel, as well as crystallization time and temperature, have a profound impact on the crystallization kinetics, resulting in zeolite solids with various degrees of crystallinity, crystal sizes and shapes. K-MER zeolite crystals with nanorod, bullet-like, prismatic and wheatsheaf-like morphologies have been successfully obtained. The catalytic performances of the K-MER zeolites in cyanoethylation of methanol, under novel non-microwave instant heating, have been investigated. The zeolite in nanosize form shows the best catalytic performance (94.1% conversion, 100% selectivity) while the bullet-like zeolite gives poorest catalytic performance (44.2% conversion, 100% selectivity). Full article
(This article belongs to the Special Issue Advances in Industrial Crystallization)
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