The Use of in Situ Tools To Monitor the Enantiotropic Transformation of <i>p</i>-Aminobenzoic Acid Polymorphs

Hao, Hongxun; Barrett, Mark; Hu, Yun; Su, Weiyi; Ferguson, Steven; Wood, Barbara; Glennon, Brian

doi:10.1021/op200141z

Cited by 54 publications

(69 citation statements)

References 18 publications

(29 reference statements)

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“…For each chosen supersaturation 120 mL of stock solution was made by dissolving the appropriate amount of PABA in the respective solvents (for toluene / benzoic acid this was reduced to 50mL). Solubility data for and polymorphs has been reported previously (13,16,18,19) but were re-measured in this work at 20°C for each solvent using a gravimetric method (five repeats).…”

Section: Methodsmentioning

confidence: 99%

Revealing the Roles of Desolvation and Molecular Self-Assembly in Crystal Nucleation from Solution: Benzoic and p-Aminobenzoic Acids

Sullivan

Davey

Sadiq

et al. 2014

Crystal Growth & Design

103

183

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Abstract. There has been much recent interest in the role of solution chemistry and in particular the importance of molecular self-assembly in the nucleation of crystalline phases.Techniques such as FTIR and NMR have highlighted the existence of solution phase dimers which in many cases mirror the structural synthons found in the resulting macroscopic crystals. However there are no reported examples in which this new insight into the solution phase has been linked directly to the kinetics of crystal nucleation. Here for the first time, using a combination of solution FTIR, computational chemistry and measured crystal nucleation rate data, such a link is demonstrated for p-aminobenzoic (PABA) and benzoic acids nucleating from polar and nonpolar solvents. Solute dimerization and desolvation are found to be rate determining processes in the overall nucleation pathway.

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Section: Methodsmentioning

confidence: 99%

Revealing the Roles of Desolvation and Molecular Self-Assembly in Crystal Nucleation from Solution: Benzoic and p-Aminobenzoic Acids

Sullivan

Davey

Sadiq

et al. 2014

Crystal Growth & Design

103

183

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“…Figure 1 Chemical structure of para-amino benzoic acid PABA contains carboxylic acid and amino functional groups and as such exhibits some of the molecular scale characteristics of pharmaceuticals and their pre-cursors 26,27,28,29,30,31,32,33 . This work focuses on the crystallisation of the alpha polymorphic form of PABA as crystallised from three solvents; ethanol, acetonitrile and water.…”

mentioning

confidence: 99%

The influence of solution environment on the nucleation kinetics and crystallisability of para-aminobenzoic acid

Turner

Corzo

Toroz

et al. 2016

Phys. Chem. Chem. Phys.

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“…For the sake of completeness, some more unusual techniques for studying catalytic reactions should also be described, which enable monitoring of changes in solid particles such as phase transformations and crystallization [24][25][26]. This could be of interest for heterogeneously catalyzed reactions, too, because coupling with spectroscopic methods, such as Raman, ATR-FTIR, and UV-vis, can provide more detailed structural information.…”

Section: Methods Couplingmentioning

confidence: 99%

“…Hao et al [25] used the same setup, but extended by ATR-FTIR spectroscopy, to study the enantiotropic transformation of p-aminobenzoic acid polymorphs. Raman spectroscopy was used to monitor the solid-phase concentration, whereas the liquid-phase concentration was monitored by ATR-FTIR spectroscopy.…”

Section: Methods Couplingmentioning

confidence: 99%

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Reaction Monitoring in Multiphase Systems: Application of CoupledIn SituSpectroscopic Techniques in Organic Synthesis

Knöpke

Bentrup

2013

Heterogeneous Catalysts for Clean Technology

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In situ spectroscopy is the only approach to obtain reliable information on mechanisms and the role of intermediates in chemical reactions as well as on structure-reactivity relationships in catalysis [1][2][3][4][5]. Especially, in heterogeneous catalysis, the application of a variety of in situ methods has gained a lively development during the recent two decades. But also in homogeneous catalysis, as well as in catalytic multiphase systems, in situ characterization methods are increasingly applied. A survey of techniques, which are most commonly applied in gas/solid and multiphase systems and the method-specific information, is presented in Table 3.1.The vibrational spectroscopies, Raman and Fourier transform infrared spectroscopy (FTIR) provide complementary information. While FTIR spectroscopy requires groups with a permanent dipole moment, Raman spectroscopy needs groups that have polarizable bonds. As a result, certain vibrations of functional groups are active or inactive in the infrared or Raman spectra, respectively. Thus, the spectra of molecules such as water or carbon monoxide show strong bands in the infrared spectra but only very weak bands in the Raman spectra. However, this is advantageous for measurements in aqueous systems. Furthermore, bands resulting from metal-nonmetal vibrations can be observed well with Raman spectroscopy. A disadvantage of Raman spectroscopy is the possible damage or fluorescence of the sample when irradiated with Raman laser light. In particular, the analysis of condensed aromatic systems can be perturbed by fluorescence. Consequently, the combination of both methods provides comprehensive information about the vibrational state of molecules or adsorbed species.Ultraviolet-visible (UV-vis) spectroscopy gives less distinct information about the molecular structure than infrared and Raman spectroscopies. Typically, the bands appearing in UV-vis spectra are rather broad. This is because of the simultaneous excitation of rotational, vibrational, and electronic transitions. The bands appearing in the UV-vis spectra of organic molecules are prominent for chromophores. These chromophores can be small parts of the sample molecule, but in extreme cases also the complete electronic shell of the sample molecule.

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The Use of in Situ Tools To Monitor the Enantiotropic Transformation of p-Aminobenzoic Acid Polymorphs

Cited by 54 publications

References 18 publications

Revealing the Roles of Desolvation and Molecular Self-Assembly in Crystal Nucleation from Solution: Benzoic and p-Aminobenzoic Acids

Revealing the Roles of Desolvation and Molecular Self-Assembly in Crystal Nucleation from Solution: Benzoic and p-Aminobenzoic Acids

The influence of solution environment on the nucleation kinetics and crystallisability of para-aminobenzoic acid

Reaction Monitoring in Multiphase Systems: Application of CoupledIn SituSpectroscopic Techniques in Organic Synthesis

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