Novel synthesis of thick wall coatings of titania supported Bi poisoned Pd catalysts and application in selective hydrogenation of acetylene alcohols in capillary microreactors

Enhanced photocatalytic degradation of amoxicillin using a spinning disc photocatalytic reactor (SDPR) with a novel Fe3O4@void@CuO/ZnO yolk-shell thin film nanostructure

Antibiotics are resistant compounds with low biological degradation that generally cannot be removed by conventional wastewater treatment processes. The use of yolk-shell nanostructures in spinning disc photocatalytic reactor (SDPR) enhances the removal efficiency due to their high surface-to-volume ratio and increased interaction between catalyst particles and reactants. The purpose of this study is to investigate the SDPR equipped to Fe3O4@void@CuO/ZnO yolk-shell thin film nanostructure (FCZ YS) in the presence of visible light illumination in the photocatalytic degradation of amoxicillin (AMX) from aqueous solutions. Stober, co-precipitation, and self-transformation methods were used for the synthesis of FCZ YS thin film nanostructure and the physical and chemical characteristics of the catalyst were analyzed by XRD, VSM,, EDX, FESEM, TEM, AFM, BET, contact angle (CA), and DRS. Then, the effect of different parameters including pH (3-11), initial concentration of AMX (10-50 mg/L), flow rate (10-25 mL/s) and rotational speed (100-400 rpm) at different times in the photocatalytic degradation of AMX were studied. The obtained results indicated that the highest degradation efficiency of 97.6% and constant reaction rate of AMX were obtained under LED visible light illumination and optimal conditions of pH = 5, initial AMX concentration of 30 mg/L, solution flow rate of 15 mL/s, rotational speed of 300 rpm and illumination time of 80 min. The durability and reusability of the nanostructure were tested, that after 5 runs had a suitable degradation rate. Considering the appropriate efficiency of amoxicillin degradation by FCZ YS nanostructure, the use of Fe3O4@void@CuO/ZnO thin film in SDPR is suggested in water and wastewater treatment processes.

Selective Hydrogenation of 2-Methyl-3-butyn-2-ol in Microcapillary Reactor on Supported Intermetallic PdZn Catalyst, Effect of Support Doping on Stability and Kinetic Parameters

The development of active, selective, and stable multicrystalline catalytic coatings on the inner surface of microcapillary reactors addresses environmental problems of fine organic synthesis, in particular by reducing the large quantities of reagents and byproducts. Thin-film nanosized bimetallic catalysts based on mesoporous pure titania and doped with zirconia, ceria, and zinc oxide, for use in microreactors, were developed, and the regularities of their formation were studied. The efficiency of PdZn/TixM1−xO2±y (M = Ce, Zr, Zn) in the hydrogenation of 2-methyl-3-butyn 2-ol was studied with an emphasis on the stability of the catalyst during the reaction. The catalytic parameters depend on the adsorption properties and activity of PdZn and Pd(0) active centers. Under reaction conditions, resistance to the decomposition of PdZn is a factor that affects the stability of the catalyst. The zinc-doped coating proved to be the most selective and stable in the reaction of selective hydrogenation of acetylenic alcohols in a microcapillary reactor. This coating retained a high selectivity of 98.2% during long-term testing up to 168 h. Modification of the morphology and electronic structure of the active component, by doping titania with Ce and Zr, is accompanied by a decrease in stability.

Homogeneous catalyst modifier for alkyne semi-hydrogenation: systematic screening in an automated flow reactor and computational study on mechanisms

21 types of modifiers are screened for palladium catalysed semi-hydrogenation of alkynes with varying catalyst type, reaction time, and target substrate using an automated flow reactor system.

Synthesis of Thin Titania Coatings onto the Inner Surface of Quartz Tubes and Their Photoactivity in Decomposition of Methylene Blue and Rhodamine B

An evaporation-deposition coating method for coating the inner surface of long (>1 m) quartz tubes of small diameter has been studied by the introduction of two-phase (gas-liquid) flow with the gas core flowing in the middle and a thin liquid film of synthesis sol flowing near the hot tube wall. The operational window for the deposition of continuous titania coatings has been obtained. The temperature range for the deposition of continuous titania coatings is limited to 105–120 °C and the gas flow rate is limited to the range of 0.4–1.0 L min−1. The liquid flow rate in the annular flow regime allows to control the coating thickness between 3 and 10 micron and the coating porosity between 10% and 20%. By increasing the liquid flow rate, the coating porosity can be substantially reduced. The coatings were characterized by X-ray diffraction, N2 chemisorption, thermogravimetric analysis, and scanning electron microscopy. The coatings were tested in the photocatalytic decomposition of methylene blue and rhodamine B under UV-light and their activity was similar to that of a commercial P25 titania catalyst.

Selectivity of the Lindlar catalyst in alkyne semi-hydrogenation: a direct liquid-phase adsorption study

Pd catalysts contain active sites that strongly adsorb alkyne and alkene molecules. The presence of the latter, alkene sites, defines the low semi-hydrogenation selectivity.

Continuous one-flow multi-step synthesis of active pharmaceutical ingredients

This review highlights a selection of multistep continuous flow (one-flow) processes leading to the synthesis of active pharmaceutical ingredients (APIs).

Emerging porous materials in confined spaces: from chromatographic applications to flow chemistry

Porous materials confined within capillary columns/microfluidic devices are discussed, and progress in chromatographic and membrane separations and catalysis is reviewed.

Counting bubbles: precision process control of gas–liquid reactions in flow with an optical inline sensor

A 10$ optical liquid sensor allows precise control of reaction conversion in gas-consuming reactions for high selectivity and catalyst utilization.

OpenFlowChem – a platform for quick, robust and flexible automation and self-optimisation of flow chemistry

OpenFlowChem – an open-access platform for automation of process control and monitoring optimised for flexibility.

Ultrasound-assisted selective hydrogenation of C-5 acetylene alcohols with Lindlar catalysts

The selective hydrogenation of 2-methyl-3-butyn-2-ol (MBY) was performed in the presence of Lindlar catalyst, comparing conventional stirring with sonication at different frequencies of 40, 380 and 850 kHz. Under conventional stirring, the reaction rates were limited by intrinsic kinetics, while in the case of sonication, the reaction rates were 50-90% slower. However, the apparent reaction rates were found to be significantly frequency dependent with the highest rate observed at 40 kHz. The original and the recovered catalysts after the hydrogenation reaction were compared using bulk elemental analysis, powder X-ray diffraction and scanning and transmission electron microscopy coupled with energy-dispersive X-ray analysis. The studies showed that sonication led to the frequency-dependent fracturing of polycrystalline support particles with the highest impact caused by 40 kHz sonication, while monocrystals were undamaged. In contrast, the leaching of Pd/Pb particles did not depend on the frequency, which suggests that sonication removed only loosely-bound catalyst particles.