Impact of Inequivalent Wetting on the Face-Specific Dissolution Rates for Single Faceted-Crystals Predicted from Solid-State Binding Energies.

A methodology for the prediction of face-specific relative dissolution rates for single-faceted crystals accounting for inequivalent wetting by the solvent is presented. This method is an extended form of a recent binding energy model developed by the authors (Najib et al., Cryst. Growth & Des. 2021, 21(3), 1482-1495) for predicting the face-specific dissolution rates for single-faceted crystals from the solid-state intermolecular binding energies in a vacuum. The principal modification is that the equivalent wetting of the crystal surfaces is no longer assumed, since interactions between the crystal surfaces and the solution-state molecules are incorporated. These surface interactions have been investigated by using a grid-based systematic search method. The face-specific dissolution rates predicted by the extended binding energy model for ibuprofen in a 95% v/v ethanol-water solution and furosemide in an aqueous medium have been validated against the published experimental results and are in excellent agreement. This model is a step forward toward accurate predictions of the relative face-specific dissolution rates for a wide variety of faceted crystals in any dissolution medium.

Development of a Digital Twin for the Prediction and Control of Supersaturation during Batch Cooling Crystallization.

Fine chemicals produced via batch crystallization with properties dependent on the crystal size distribution require precise control of supersaturation, which drives the evolution of crystal size over time. Model predictive control (MPC) of supersaturation using a mechanistic model to represent the behavior of a crystallization process requires less experimental time and resources compared with fully empirical model-based control methods. Experimental characterization of the hexamine-ethanol crystallization system was performed in order to collect the parameters required to build a one-dimensional (1D) population balance model (PBM) in gPROMS FormulatedProducts software (Siemens-PSE Ltd.). Analysis of the metastable zone width (MSZW) and a series of seeded batch cooling crystallizations informed the suitable process conditions selected for supersaturation control experiments. The gPROMS model was integrated with the control software PharmaMV (Perceptive Engineering Ltd.) to create a digital twin of the crystallizer. Simulated batch crystallizations were used to train two statistical MPC blocks, allowing for in silico supersaturation control simulations to develop an effective control strategy. In the supersaturation set-point range of 0.012-0.036, the digital twin displayed excellent performance that would require minimal controller tuning to steady out any instabilities. The MPC strategy was implemented on a physical 500 mL crystallizer, with the simulated solution concentration replaced by in situ measurements from calibrated attenuated total reflection-Fourier transform infrared (ATR-FTIR) spectroscopy. Physical supersaturation control performance was slightly more unstable than the in silico tests, which is consistent with expected disturbances to the heat transfer, which were not specifically modeled in simulations. Overall, the level of supersaturation control in a real crystallizer was found to be accurate and precise enough to consider future adaptations to the MPC strategy for more advanced control objectives, such as the crystal size.

Composition and source apportionment of saccharides in aerosol particles from an agro-industrial zone in the Indo-Gangetic Plain.

The characterization of saccharidic compounds in atmospheric aerosols is important in order to retrieve information about organic carbon sources and their transport pathways through the atmosphere. In this study, composition and sources of saccharides in PM10 were determined in a South Asian megacity (Faisalabad) during the year 2015 - 2016. PM10 sampled on quartz filters was analyzed by anion exchange chromatography for the selected saccharidic compounds. The average PM10 concentration was found to be 744 ± 392 µg m-3, exceeding the daily limits proposed by Pak-EPA (150 µg m-3), US-EPA (150 µg m-3), and WHO (50 µg m-3). The average total saccharidic concentration was found to be 2820 ± 2247 ng m-3. Among the different saccharidic categories, anhydrosugars were the most abundant in concentration followed by primary sugars and sugar alcohols. The correlation and principal component analysis indicated emissions from biomass combustion, soil suspensions from areas such as farmlands having high microorganism activity, and biogenic emissions such as airborne fungal spores and vegetation detritus as major sources of saccharides in the aerosol samples.

Structural investigation of some novel synthesized Schiff base Transition metal complexes derived from drug together with Antimicrobial study.

A new series of copper (II), cobalt (II), zinc (II), nickel (II), manganese (II), iron (II) complexes with a novel Schiff base were synthesized by the condensation of sulphadizine and thiophene-2-carbaldehyde.The ligand and its complexes were characterized by using diverse instrumental procedures like microanalysis, thermo gravimetric examination and spectroscopy. The integrated ligand and its metal complexes were subjected to antibacterial studies. These studies demonstrated the enhanced activity of metal complexes against reported microbes with respect to the Schiff base.

Determination of nitenpyram and 6-chloronicotinic acid in environmental samples by ion chromatography coupled with online photochemically induced fluorescence detector.

A simple, cost-effective, sensitive, and quick method for the determination of nitenpyram and its metabolite 6-chloronicotinic acid in environmental samples was developed by coupling an ion chromatograph with a fluorescence detector and a post-column photochemical reactor. This developed analytical method involved a rapid sample extraction by modified and miniaturized quick, easy, cheap, effective, rugged, and safe method followed by isocratic ion chromatographic separation of nitenpyram and 6-chloronicotinic acid into an IonPac™ AS11-HC column protected by IonPac™ AG11A guard column by running 30 mM NaOH + 10% acetonitrile mobile phase. A homemade post-column photochemical reactor was also integrated with the ion chromatographic system for online transformation of both analytes into their respective highly fluorescent photoproduct in basic media without using an extra pump. The developed method was validated by following SANTE/11945/2015 guidelines on analytical quality control and validation procedures. The method showed a good linear response (r > 0.999), improved limit of detection (0.101-0.132 µg/L), minimum or no matrix effect, excellent recoveries (90.2-100.10%) and relative standard deviations were found to be ≤6.50%.

N-[4-(Phenyl-imino-meth-yl)phen-yl]acetamide 0.67-hydrate.

The title compound, C(15)H(14)N(2)O·0.67H(2)O, was prepared by the reaction of 4-acetoamine-benzaldehyde and aniline. The asymmetric unit contains six organic mol-ecules and four water mol-ecules. The dihedral angles between the aromatic ring planes in each organic mol-ecule vary from 42.4 (2) to 53.8 (2)°. In the crystal, an extensive network of inter-molecular N-H⋯O, O-H⋯N and O-H⋯O hydrogen bonds link the mol-ecules into [010] chains.

Bis(2-chloro-benz-yl)dimethyl-ammonium bromide.

In the title compound, C(16)H(18)Cl(2)N(+)·Br(-), the dihedral angle between the aromatic ring planes is 57.73 (5)°. In the absence of any strong hydrogen bonds, the structure results from a large number of competing weaker inter-actions including Cl⋯Cl [3.4610 (5) Å] and C-H⋯Cl contacts and both (aryl) C-H⋯Br and N(+)-Csp(3)-H⋯Br(-) cation-anion inter-actions.

Tyrosinase-inhibitory long-chain esters from Amberboa ramosa.

Long-chain esters 1 and 2 have been isolated from the chloroform-soluble fraction of Amberboa ramosa and their structures assigned to be methyl 2beta(2S)-hydroxyl-7(E)-tritriacontenoate (1) and methyl 2beta(2S)-O-beta-D-galactopyranosyl-7(E)-tetratriacontenoate (2). In addition, tricontane (3) and apigenin (4) are also reported for the first time from this species. The structures were assigned on the basis of 1D and 2D NMR techniques. Compounds 1 and 2 showed strong to moderate inhibitory activity against tyrosinase.