The solubility and nucleation of borax decahydrate in the presence of Cl– and SO42– ions have been studied by two different methods: polythermal crystallization and isothermal crystallization. The results revealed that both anions had a salt-in effect on the solubility. A noticeable widening of the metastable zone was observed after the addition of the two anion impurities. For the isothermal crystallization, two different nucleation mechanisms were obtained. When the supersaturation ratio S > 1.3, the nucleation appears to be homogeneous, whereas at the supersaturation ratio S < 1.25, heterogeneous nucleation predominates. From the prolonged induction period in the presence of the two anions, we conclude that the nucleation of borax decahydrate was suppressed after the addition of impurities. The values of the interfacial energy γ calculated by isothermal method are lower than those obtained by polythermal method due to the underestimated values of ln S.

Effect of Impurities on the Solubility, Metastable Zone Width, and Nucleation Kinetics of Borax

Cocrystallization has been recognized as one of the most successful approaches to address stability problems of active pharmaceutical ingredients (APIs) in the past few decades. However, scant attention has been...

Enhancing the stability of active pharmaceutical ingredients by cocrystal strategy

For the purpose of enhancing the solubility and humidity stability of pymetrozine (PMZ), a highly active but nonbiocidal pesticide, new multicomponent crystals were developed based on the connotati...

New Salts and Cocrystals of Pymetrozine with Improvements on Solubility and Humidity Stability: Experimental and Theoretical Study

Evaluation on Cocrystal Screening Methods and Synthesis of Multicomponent Crystals: A Case Study

Image analysis enables the estimation of critical process properties such as crystal size, morphology, and crystallization kinetics. Despite the rich image information, the lack of a robust image analysis technique has been an obstacle to promote its applications. In this work, an automated image analysis technique that combines the state-of-the-art oriented object detection model, S2A-Net, was developed for in situ estimation of the two-dimensional crystal size distribution (CSD) and the crystal counts. The model was trained to detect and classify both crystals and clusters to enable quantification of the extent of agglomeration and exclude unreliable detections. The effectiveness and robustness of extracting size and aspect ratio at various image complexities were verified by comparing with the focused beam reflective measurement (FBRM) and manually analyzed images in the experimental studies for taurine batch cooling crystallization with different seed loadings. An on-line calibration strategy for solute concentration measurement with Raman spectroscopy was introduced to eliminate the dedicated calibration experiments. The secondary nucleation and growth rate kinetics were evaluated from the on-line measurements and validated by numerical simulation. The proposed method provides a novel PAT strategy that enables accurate two-dimensional size measurement and shape characterization for online monitoring and control of a solution crystallization process.

Deep learning-based oriented object detection for in situ image monitoring and analysis: A process analytical technology (PAT) application for taurine crystallization

Solubility measurement and thermodynamic correlation of (2,4-dichlorophenoxy)acetic acid in fifteen pure solvents

Effect of Sodium Sulfate on Nucleation Behavior and the Crystal Morphology of Taurine

Nicosulfuron (NS) is a widely used sulfonylurea herbicide because of its high selectivity, broad spectrum of herbicide activity, and excellent performance. In this work, nicosulfuron methanol solvate (NS-MeOH) and [[3-[(Dimethylamino)carbonyl]-2-pyridinyl]sulfonyl]carbamic acid methyl ester (PCM) as a product of methanolysis of NS were obtained. Both of their structures were determined by a single crystal X-ray diffraction. A broad range of analytical techniques was applied to characterize the NS-MeOH, such as Powder X-ray diffraction (PXRD), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and hot stage microscopy (HSM). Combined with the analysis of the Independent gradient model (IGM), Atom-in-molecules (AIM), and Hirshfeld surface (HS), direct insights into the role of solvent played in the formation of NS-MeOH and the mechanism of solid-to-solid phase transformation of NS-MeOH could be obtained. In addition, the aqueous solubility of NS was improved through the formation of NS-MeOH. A systematic investigation of herbicidal activity of NS and PCM was carried out. It was found that NS and NS-MeOH had similar herbicidal activities at the experimental concentrations while PCM exhibited significantly lower activity. It was suggested that methanolysis of the sulfonylurea bridge in the NS molecule exerted a great influence on the herbicidal activity.

https://www.mdpi.com/2073-4352/10/3/157/pdf

Bei Zhang

Papers

New Salts and Cocrystals of Pymetrozine with Improvements on Solubility and Humidity Stability: Experimental and Theoretical Study

Evaluation on Cocrystal Screening Methods and Synthesis of Multicomponent Crystals: A Case Study

Solubility measurement and thermodynamic correlation of (2,4-dichlorophenoxy)acetic acid in fifteen pure solvents

Effect of Sodium Sulfate on Nucleation Behavior and the Crystal Morphology of Taurine

Toward an Understanding of the Formation and Desolvation of Methanol Solvate, and Structure of Methanolysis Product: A Case Study of Nicosulfuron