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The production of microcapsules by electrospraying two immiscible liquids from oppositely charged parallel nozzles and the subsequent microcapsule collection constitute an electroencapsulation process influenced by numerous parameters. The electroencapsulation parameters include the liquid properties, e.g. bulk liquid conductivity K , viscosity η , density ρ , and surface tension γ ; the electric field, gravity field, and the electrospraying and collection geometries; and the atmospheric properties. In the present work, NaI-doped glycerol was used as core liquid, with an optional payload of dispersed thermally carbonized porous silicon nanoparticles (PSi). Chloroform with dissolved Eudragit E 100 cationic copolymer and dispersed talc particles as an anti-tacking agent was used as shell liquid. The influence of varying ten electrospraying parameters (liquid flow rates Q i , electrospraying voltages | U i | and polarity, solid concentrations, and temperature T ) within the cone-jet mode regime on the structure and yield of microcapsules produced by parallel nozzle electroencapsulation was investigated simultaneously using the Taguchi robust design method. Of the investigated parameters, the most important were found to be NaI concentration and T , both influencing the core liquid conductivity; and the liquid flow rates. The Taguchi experiment and additional results suggest that optimally, the parameters affecting liquid conductivities should be set for a coarse atomization current balance when using a maximal shell liquid flow rate. Then, the core liquid flow rate can be adjusted for best process efficiency. [ABSTRACT FROM AUTHOR]

The aim of the research was to verify that electrospraying of piroxicam yielded a new polymorphic form of this drug. In the experiments, piroxicam was dissolved in chloroform and the solution was atomised electrostatically. Subsequently, the charged droplets were neutralised and dried. The solid drug particles were collected and analysed by scanning electron microscopy, X-ray diffraction, differential scanning calorimetry, high performance liquid chromatography, and infrared and Raman spectroscopy. The X-ray diffractogram measured for the electrosprayed piroxicam particles did not match with any of the known piroxicam crystal structures ( Cambridge Crystallographic Data Centre ). The variable temperature X-ray diffraction showed that the structure recrystallised completely into piroxicam polymorphic form I during heating. No degradation products or solvate removal was detected by high performance liquid chromatography and thermal analysis. The infrared and Raman spectra of the electrosprayed piroxicam were compared to those of form I, and some notable differences in the peak positions, shapes and intensities were detected. The results indicate that electrospraying leads to piroxicam crystallisation in a currently unknown polymorphic form. [ABSTRACT FROM AUTHOR]

Abstract: The feasibility of electroencapsulation of mesoporous silicon (PSi) micro- and nanoparticles as a method to seal the PSi particles in mechanically processable solid units, and to facilitate time and site specific drug release from the pores of PSi particles, is of interest in the present work. Suitable microcapsules and micromatrix particles were produced in a single-step process using a setup with two electrospraying nozzles kept at high electric potentials of opposite polarities. The structures of the produced particles were analyzed by microscope and X-ray micro- and nanotomography imaging, and optimization of the electroencapsulation process production efficiency is discussed. [Copyright &y& Elsevier]

Graphical abstract Preparation of 16 wt% CeO2 supported on TiO2, SiO2 and Al2O3 catalysts prepared using evaporation impregnation (evimp.) and deposition precipitation (dp.) and their testing in direct synthesis of diethylcarbonate from CO2 and ethanol using butylene oxide as the water trap. Highlights • Ceria—supported on Al 2 O 3 , SiO 2 and TiO 2 catalysts were synthesized and characterized. • 16 wt% CeO 2 -SiO 2 catalyst exhibited the highest activity to diethylcarbonate. • High basicity is required for diethylcarbonate synthesis from CO 2 and ethanol. Abstract The support materials Al 2 O 3 , SiO 2 and TiO 2 were modified with 16 wt% CeO 2 , using two different preparation methods evaporation-impregnation and precipitation-deposition. The synthesized 16 wt% CeO 2 -Al 2 O 3 , 16 wt% CeO 2 -SiO 2 and 16 wt% CeO 2 -TiO 2 materials were characterized by means of X-ray powder diffraction for the phase purity, scanning electron microscopy for the morphology, nitrogen physisorption to determine the specific surface area and X-ray photo electron spectroscopy for the oxidation state of the Ce in the TiO 2 , Al 2 O 3 and SiO 2 matrices. Transmission electron microscopy was used to study the particle size of CeO 2 whereas CO 2 -temperature programmed desorption (TPD) was used to determine the basicity of ceria-modified TiO 2 , Al 2 O 3 and SiO 2 catalysts. Furthermore, the catalytic performance of the as prepared CeO 2 -modified catalysts were compared in the synthesis of diethyl carbonate starting from ethanol and CO 2 using butylene oxide as the dehydrating agent. The physico-chemical characterization results were correlated with the catalytic activity results and discussed in detail. [ABSTRACT FROM AUTHOR]

Partial oxidation of ethanol to acetaldehyde was carried out over gold catalysts supported on various oxides and zeolites by deposition precipitation. The special focus of this work was on the influence of H-Y zeolite surface charge on Au cluster size and loading linking it to activity and selectivity in ethanol oxidation and comparing with other studied catalysts. The catalysts were characterized by nitrogen physisorption, transmission electron microscopy (TEM), scanning electron microscopy/energy dispersive X-ray analysis (SEM/EDXA), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR) and zeta potential measurements. pH of the solution governed the Au NPs size within the range of 5.8–13.2 nm with less negatively charged surfaces leading to formation of smaller clusters. Au loading on H-Y zeolite with silica to alumina ratio of 80 was increased by raising the pH. In fact, H-Y-12 and H-Beta-25 were selective towards diethyl ether while acetaldehyde was the prevalent product on less acidic H-Y-80. The results demonstrated strong dependency of the catalytic activity on the Au cluster size. Namely turn over frequency (TOF) decreased with an increase in metal size from 6.3 to 9.3 nm on H-Y-80. Selectivity towards acetaldehyde and ethyl acetate did not change significantly on H-Y-80 within 6.3–9.3 nm Au particle size range. On Al 2 O 3 support, however, selectivity towards acetaldehyde increased considerably upon diminishing Au average particle size from 3.7 to 2.1 nm. [ABSTRACT FROM AUTHOR]

Sulfur-free Ni supported on H-Y zeolites, γ-Al 2 O 3 and SiO 2 synthesized by the wet impregnation method, and Pd/C were tested in hydrodeoxygenation (HDO) of stearic acid. The catalysts were forming n- heptadecane except Ni/H-Y-80, which was producing n- heptadecane and n- octadecane. Ni/H-Y 80 and Pd/C were tested on HDO of fatty acid methyl esters from chlorella, tall oil fatty acids, and animal fat. The reactions converting the substrates to the final products followed the path from unsaturated esters to acids, with hydrogenation of the latter into alcohols (i.e., stearyl alcohol), and finally formation of hydrocarbons. Ni/H-Y-80 permitted rapid and complete conversion into hydrocarbons, while Pd/C displayed 5–20 times lower turnover frequency, producing saturated intermediates along with hydrocarbons. The catalyst reusability of Ni supported on Y zeolites was studied by recycling and regenerating the spent catalyst from fatty acid HDO. The catalysts demonstrated the possibility of restoring the rates per unit of surface area after regeneration. Catalysts used in HDO of different feedstocks were investigated by thermogravimetric analysis, inductively coupled plasma-optical emission spectroscopy, transmission electron microscopy, surface area measurements, and pore size analysis. [ABSTRACT FROM AUTHOR]

The influence of the size and oxidation state of Au nanoparticles (AuNPs) as electrocatalysts for the electro-oxidation of cellulose was studied. Carbon paper electrodes modified with AuNPs were used as the electrocatalysts for the electro-oxidation of cellulose dissolved in 1.3 m NaOH. The size and oxidation state of the AuNPs were determined by using SEM, TEM, and X-ray photoelectron spectroscopy. Both the size and the oxidation state of the AuNPs were found to influence the electrocatalytic properties of the electrode, as studied by using cyclic voltammetry, square wave voltammetry, and electrochemical impedance spectroscopy. The carbon paper electrodes decorated with AuNPs (less than 25 nm) that consist of metallic Au gave rise to a significantly higher electrocatalytic activity than a bare polycrystalline Au electrode. [ABSTRACT FROM AUTHOR]

A potentiometric acid–base titration method was developed to characterize the acid–base properties of H-Beta-25, H-Beta-300, H-Ferrierite-20 and Si-MCM-48 zeolites in aqueous solutions. The method is based on linearization of the titration curve. The zeolite powders were dispersed in a sodium nitrate solution which was then titrated with a standard solution of sodium hydroxide. Various acid sites were found in the studied zeolites, and both the protonation constants and the concentrations of these acid sites were determined. The chemical composition (aluminum and silicon), distribution of the aluminum sites, crystallinity as well as the acidic properties of the titrated zeolites were compared with those of the pristine zeolites by using Inductively Coupled Plasma Optical Emission Spectrometer (ICP-OES), X-ray Diffraction (XRD), 27 Al NMR spectroscopy and the commonly used gas phase Fourier Transform Infrared spectroscopy (FTIR) of pyridine adsorption method. [ABSTRACT FROM AUTHOR]

Polypyrrole/zeolite composites were synthesized by electrochemical polymerization of pyrrole monomer at ambient temperature (22 ± 1 °C) in aqueous suspension of pure microporous zeolite particles. Electrodeposition was performed by using the method of constant potential. The proton form of Beta zeolites with SiO/AlO ratios of 25 and 300 and Y zeolites with SiO/AlO ratios of 12 and 80 was used in this work. The chemical compositions and the acidic properties of the zeolites were studied by inductively coupled plasma optical emission spectrometer and potentiometric acid-base titration. Polypyrrole/zeolite composite films deposited on platinum and indium tin oxide glass electrodes were characterized by scanning electron microscopy, Fourier transform infrared spectroscopy with attenuated total reflectance, X-ray diffraction, and transmission electron micrographs, and their electrochemical behavior was studied by cyclic voltammetry. These measurements showed that polymerization of pyrrole took place on the outer surfaces of the host zeolite crystals. The oxidized cationic polypyrrole was charge-balanced by the anionic groups present in the zeolite framework. Content of the anionic groups in the zeolites was found to be important for the electrochemical behavior of the polypyrrole/zeolite composites. [ABSTRACT FROM AUTHOR]

Highlights: [•] Transformation of α-pinene oxide to campholenic aldehyde in toluene. [•] Synthesis of Fe Beta-75; ZSM-5, MCM-41 by impregnation and solid-state ion exchange. [•] Extensive characterization of catalysts. [•] Strong influence of acidity on activity and selectivity. [•] The highest selectivity of 66% with Fe-MCM-41. [Copyright &y& Elsevier]