Kinetics of (R,S)- and (R)-mandelic acid in an unseeded cooling batch crystallizer

Mao, Shimin; Zhang, Yan; Rohani, Sohrab; Ray, Ajay K.

doi:10.1016/j.jcrysgro.2010.08.027

Cited by 11 publications

(16 citation statements)

References 26 publications

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“…The spectrum of 1-propanol at room temperature was used as the background for each sample. Mao et al [ 20 ] have demonstrated that the relative peak proportionally increased with the solute concentration and was almost insensitive to temperature. In order to reduce the effect of noise, the absorbance intensity at 1251 cm −1 was subtracted from absorbance intensity peak heights at 1400 and 1677 cm −1 .…”

Section: Resultsmentioning

confidence: 99%

In Situ Focused Beam Reflectance Measurement (FBRM), Attenuated Total Reflectance Fourier Transform Infrared (ATR-FTIR) and Raman Characterization of the Polymorphic Transformation of Carbamazepine

et al. 2012

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The objective of this work was to study the polymorphic transformation of carbamazepine from Form II to Form III in 1-propanol during seeded isothermal batch crystallization. First, the pure Form II and Form III were obtained and characterized. Then their solubilities and metastable zone limits were measured by in-situ attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy and focused beam reflectance measurement (FBRM). A transition temperature at about 34.2 °C was deduced suggesting the enantiotropic nature of this compound over the studied temperature range. To quantify the polymorph ratio during the transformation process, a new in-situ quantitative method was developed to measure the fraction of Form II by Raman spectroscopy. Successful tracking of the nucleation of the stable form and the transformation from Form II to Form III during isothermal crystallization was achieved by Raman spectroscopy and FBRM. The results from these three in-situ techniques, FBRM, FTIR and Raman were consistent with each other. The results showed a strong dependency on the amount of seeds added during isothermal crystallization.

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Section: Resultsmentioning

confidence: 99%

In Situ Focused Beam Reflectance Measurement (FBRM), Attenuated Total Reflectance Fourier Transform Infrared (ATR-FTIR) and Raman Characterization of the Polymorphic Transformation of Carbamazepine

et al. 2012

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“…The spectrum of 1-propanol at room temperature was used as the background for each sample. Mao et al 20 have demonstrated that the relative height of chosen characteristic peaks increased proportionally with the solute concentration and was almost insensitive to temperature. With a comparison of all the peaks, …”

Section: Quantitative Methodsmentioning

confidence: 99%

Combined Application of in Situ FBRM, ATR-FTIR, and Raman on Polymorphism Transformation Monitoring During the Cooling Crystallization

Zhao¹,

Yuan²,

Ji³

et al. 2012

Ind. Eng. Chem. Res.

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This study evaluates the potential use of the FBRM, ATR-FTIR, and Raman for on line detection of polymorphic transformation of carbamazepine (CBZ) during the cooling crystallization. Changes in solution concentration as a function of time were quantified from the ATR-FTIR data. A new quantitative method of polymorphs ratio was developed using Raman spectroscopy for in situ monitoring during a solution-mediated transformation of carbamazepine from form II to form III in 1-propanol. The polymorphic forms initially crystallized from solution, in the absence of seeds, could be clearly identified by FBRM and showed good agreement with results of microscopic images. Furthermore, the kinetics of the conversion of carbamazepine from metastable form to the stable form at different cooling rates could be readily followed.

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“…For example, for the R ‐MA case, Ref. studies the unseeded cooling batch crystallizer to evaluate the growth and nucleation. A growth‐only kinetics evaluation of S ‐mandelic acid and the opposite enantiomer effects were investigated by Ref.…”

Section: Batch Crystallizer Model With Fines Dissolution Loopmentioning

confidence: 99%

“…Two major approaches for enantiomeric separation are asymmetric synthesis and chiral resolution. Although the former technology has progressed significantly, it still has limited application, or it may have a prohibitive cost . Thus, chiral resolution methods are in development to achieve cost‐effective, reliable and flexible enantioselective separation processes (for a detailed review of both approaches see Ref.…”

Section: Introductionmentioning

confidence: 99%

Optimal operation of batch enantiomer crystallization: From ternary diagrams to predictive control

et al. 2017

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In this work, the modeling and control of batch crystallization for racemic compound forming systems is addressed in a systematic fashion. Specifically, a batch crystallization process is considered for which the initial solution has been preenriched in the desired enantiomer to enable crystallization of only the preferred enantiomer. A method for determining desired operating conditions (composition of the initial pre-enriched solution and temperature to which the mixture must be cooled for maximum yield) for the batch crystallizer based on a ternary diagram for the enantiomer mixture in a solvent is described. Subsequently, it is shown that the information obtained from the ternary diagram, such as the maximum yield attainable from the process due to thermodynamics, can be used to formulate constraints for an optimization-based control method to achieve desired product characteristics such as a desired yield. The proposed method is demonstrated for the batch crystallization of mandelic acid in a crystallizer with a fines trap that is seeded with crystals of the desired enantiomer. The process is controlled with an optimization-based controller to minimize the ratio of the mass of crystals obtained from nuclei to the mass obtained from seeds while maintaining the desired enantioseparation.

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Kinetics of (R,S)- and (R)-mandelic acid in an unseeded cooling batch crystallizer

Cited by 11 publications

References 26 publications

In Situ Focused Beam Reflectance Measurement (FBRM), Attenuated Total Reflectance Fourier Transform Infrared (ATR-FTIR) and Raman Characterization of the Polymorphic Transformation of Carbamazepine

In Situ Focused Beam Reflectance Measurement (FBRM), Attenuated Total Reflectance Fourier Transform Infrared (ATR-FTIR) and Raman Characterization of the Polymorphic Transformation of Carbamazepine

Combined Application of in Situ FBRM, ATR-FTIR, and Raman on Polymorphism Transformation Monitoring During the Cooling Crystallization

Optimal operation of batch enantiomer crystallization: From ternary diagrams to predictive control

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